From 988f7b5789ccf5cfed14c72e28573a49f0cb4809 Mon Sep 17 00:00:00 2001 From: "venkatesh.pallipadi@intel.com" Date: Tue, 18 Mar 2008 17:00:22 -0700 Subject: x86: PAT export resource_wc in pci sysfs For the ranges with IORESOURCE_PREFETCH, export a new resource_wc interface in pci /sysfs along with resource (which is uncached). Signed-off-by: Venkatesh Pallipadi Signed-off-by: Suresh Siddha Acked-by: Jesse Barnes Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- Documentation/filesystems/sysfs-pci.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation') diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt index 5daa2aaec2c5..68ef48839c04 100644 --- a/Documentation/filesystems/sysfs-pci.txt +++ b/Documentation/filesystems/sysfs-pci.txt @@ -36,6 +36,7 @@ files, each with their own function. local_cpus nearby CPU mask (cpumask, ro) resource PCI resource host addresses (ascii, ro) resource0..N PCI resource N, if present (binary, mmap) + resource0_wc..N_wc PCI WC map resource N, if prefetchable (binary, mmap) rom PCI ROM resource, if present (binary, ro) subsystem_device PCI subsystem device (ascii, ro) subsystem_vendor PCI subsystem vendor (ascii, ro) -- cgit v1.2.3 From c6c67c1afcce71335b18ed8769b1165c468bfb03 Mon Sep 17 00:00:00 2001 From: Pekka Paalanen Date: Mon, 12 May 2008 21:20:59 +0200 Subject: mmiotrace: add user documentation Signed-off-by: Pekka Paalanen Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- Documentation/tracers/mmiotrace.txt | 153 ++++++++++++++++++++++++++++++++++++ 1 file changed, 153 insertions(+) create mode 100644 Documentation/tracers/mmiotrace.txt (limited to 'Documentation') diff --git a/Documentation/tracers/mmiotrace.txt b/Documentation/tracers/mmiotrace.txt new file mode 100644 index 000000000000..84246f703875 --- /dev/null +++ b/Documentation/tracers/mmiotrace.txt @@ -0,0 +1,153 @@ + In-kernel memory-mapped I/O tracing + + +Home page and links to optional user space tools: + + http://nouveau.freedesktop.org/wiki/MmioTrace + +MMIO tracing was originally developed by Intel around 2003 for their Fault +Injection Test Harness. In Dec 2006 - Jan 2007, using the code from Intel, +Jeff Muizelaar created a tool for tracing MMIO accesses with the Nouveau +project in mind. Since then many people have contributed. + +Mmiotrace was built for reverse engineering any memory-mapped IO device with +the Nouveau project as the first real user. Only x86 and x86_64 architectures +are supported. + +Out-of-tree mmiotrace was originally modified for mainline inclusion and +ftrace framework by Pekka Paalanen . + + +Preparation +----------- + +Mmiotrace feature is compiled in by the CONFIG_MMIOTRACE option. Tracing is +disabled by default, so it is safe to have this set to yes. SMP systems are +supported, but tracing is unreliable and may miss events if more than one CPU +is on-line, therefore mmiotrace takes all but one CPU off-line during run-time +activation [not implemented]. + + +Usage Quick Reference +--------------------- + +$ mount -t debugfs debugfs /debug +$ echo mmiotrace > /debug/tracing/current_tracer +$ cat /debug/tracing/trace_pipe > mydump.txt & +Start X or whatever. +$ echo "X is up" > /debug/tracing/marker +$ echo none > /debug/tracing/current_tracer +Check kernel log. + + +Usage +----- + +Make sure debugfs is mounted to /debug. If not, (requires root privileges) +$ mount -t debugfs debugfs /debug + +Check that the driver you are about to trace is not loaded. + +Activate mmiotrace (requires root privileges): +$ echo mmiotrace > /debug/tracing/current_tracer + +Start storing the trace: +$ cat /debug/tracing/trace_pipe > mydump.txt & +The 'cat' process should stay running (sleeping) in the background. + +Load the driver you want to trace and use it. Mmiotrace will only catch MMIO +accesses to areas that are ioremapped while mmiotrace is active. + +[Unimplemented feature:] +During tracing you can place comments (markers) into the trace by +$ echo "X is up" > /debug/tracing/marker +This makes it easier to see which part of the (huge) trace corresponds to +which action. It is recommended to place descriptive markers about what you +do. + +Shut down mmiotrace (requires root privileges): +$ echo none > /debug/tracing/current_tracer +The 'cat' process exits. If it does not, kill it by 'fg' and pressing ctrl+c. + +[This feature is not implemented yet!] +Check your kernel log. If there are messages about mmiotrace losing events, +this is due to buffer overrun, and the trace is incomplete. You should enlarge +the buffers and try again. [How?] + +If you are doing a trace for a driver project, e.g. Nouveau, you should also +do the following before sending your results: +$ lspci -vvv > lspci.txt +$ dmesg > dmesg.txt +$ tar zcf pciid-nick-mmiotrace.tar.gz mydump.txt lspci.txt dmesg.txt +and then send the .tar.gz file. The trace compresses considerably. Replace +"pciid" and "nick" with the PCI ID or model name of your piece of hardware +under investigation and your nick name. + + +How Mmiotrace Works +------------------- + +Access to hardware IO-memory is gained by mapping addresses from PCI bus by +calling one of the ioremap_*() functions. Mmiotrace is hooked into the +__ioremap() function and gets called whenever a mapping is created. Mapping is +an event that is recorded into the trace log. Note, that ISA range mappings +are not caught, since the mapping always exists and is returned directly. + +MMIO accesses are recorded via page faults. Just before __ioremap() returns, +the mapped pages are marked as not present. Any access to the pages causes a +fault. The page fault handler calls mmiotrace to handle the fault. Mmiotrace +marks the page present, sets TF flag to achieve single stepping and exits the +fault handler. The instruction that faulted is executed and debug trap is +entered. Here mmiotrace again marks the page as not present. The instruction +is decoded to get the type of operation (read/write), data width and the value +read or written. These are stored to the trace log. + +Setting the page present in the page fault handler has a race condition on SMP +machines. During the single stepping other CPUs may run freely on that page +and events can be missed without a notice. Re-enabling other CPUs during +tracing is discouraged. + + +Trace Log Format +---------------- + +The raw log is text and easily filtered with e.g. grep and awk. One record is +one line in the log. A record starts with a keyword, followed by keyword +dependant arguments. Arguments are separated by a space, or continue until the +end of line. The format for version 20070824 is as follows: + +Explanation Keyword Space separated arguments +--------------------------------------------------------------------------- + +read event R width, timestamp, map id, physical, value, PC, PID +write event W width, timestamp, map id, physical, value, PC, PID +ioremap event MAP timestamp, map id, physical, virtual, length, PC, PID +iounmap event UNMAP timestamp, map id, PC, PID +marker MARK timestamp, text +version VERSION the string "20070824" +info for reader LSPCI one line from lspci -v +PCI address map PCIDEV space separated /proc/bus/pci/devices data +unk. opcode UNKNOWN timestamp, map id, physical, data, PC, PID + +Timestamp is in seconds with decimals. Physical is a PCI bus address, virtual +is a kernel virtual address. Width is the data width in bytes and value is the +data value. Map id is an arbitrary id number identifying the mapping that was +used in an operation. PC is the program counter and PID is process id. PC is +zero if it is not recorded. PID is always zero as tracing MMIO accesses +originating in user space memory is not yet supported. + +For instance, the following awk filter will pass all 32-bit writes that target +physical addresses in the range [0xfb73ce40, 0xfb800000[ + +$ awk '/W 4 / { adr=strtonum($5); if (adr >= 0xfb73ce40 && +adr < 0xfb800000) print; }' + + +Tools for Developers +-------------------- + +The user space tools include utilities for: +- replacing numeric addresses and values with hardware register names +- replaying MMIO logs, i.e., re-executing the recorded writes + + -- cgit v1.2.3 From 6f6f394d9ca61fcc73ecfd2f2bf58e92dc1ab269 Mon Sep 17 00:00:00 2001 From: Pekka Paalanen Date: Mon, 12 May 2008 21:21:03 +0200 Subject: doc: update mmiotrace doc to current status Signed-off-by: Pekka Paalanen Signed-off-by: Ingo Molnar --- Documentation/tracers/mmiotrace.txt | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) (limited to 'Documentation') diff --git a/Documentation/tracers/mmiotrace.txt b/Documentation/tracers/mmiotrace.txt index 84246f703875..a4afb560a45b 100644 --- a/Documentation/tracers/mmiotrace.txt +++ b/Documentation/tracers/mmiotrace.txt @@ -25,7 +25,8 @@ Mmiotrace feature is compiled in by the CONFIG_MMIOTRACE option. Tracing is disabled by default, so it is safe to have this set to yes. SMP systems are supported, but tracing is unreliable and may miss events if more than one CPU is on-line, therefore mmiotrace takes all but one CPU off-line during run-time -activation [not implemented]. +activation. You can re-enable CPUs by hand, but you have been warned, there +is no way to automatically detect if you are losing events due to CPUs racing. Usage Quick Reference @@ -37,7 +38,7 @@ $ cat /debug/tracing/trace_pipe > mydump.txt & Start X or whatever. $ echo "X is up" > /debug/tracing/marker $ echo none > /debug/tracing/current_tracer -Check kernel log. +Check for lost events. Usage @@ -67,12 +68,22 @@ do. Shut down mmiotrace (requires root privileges): $ echo none > /debug/tracing/current_tracer -The 'cat' process exits. If it does not, kill it by 'fg' and pressing ctrl+c. - -[This feature is not implemented yet!] -Check your kernel log. If there are messages about mmiotrace losing events, -this is due to buffer overrun, and the trace is incomplete. You should enlarge -the buffers and try again. [How?] +The 'cat' process exits. If it does not, kill it by issuing 'fg' command and +pressing ctrl+c. + +Check that mmiotrace did not lose events due to a buffer filling up. Either +$ grep -i lost mydump.txt +which tells you exactly how many events were lost, or use +$ dmesg +to view your kernel log and look for "mmiotrace has lost events" warning. If +events were lost, the trace is incomplete. You should enlarge the buffers and +try again. Buffers are enlarged by first seeing how large the current buffers +are: +$ cat /debug/tracing/trace_entries +gives you a number. Approximately double this number and write it back, for +instance: +$ echo 128000 > /debug/tracing/trace_entries +Then start again from the top. If you are doing a trace for a driver project, e.g. Nouveau, you should also do the following before sending your results: -- cgit v1.2.3 From cca7c0850fa0381639bf84dd06ee900e16346373 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Mon, 12 May 2008 15:43:37 +0200 Subject: x86_64: fix mm.txt documentation Commit 85eb69a16aab5a394ce043c2131319eae35e6493 introduced 512 MiB sized kernel and 1.5 GiB sized module space but omitted to change documentation properly. Fix that. [Wasn't the hole intentional protection hole?] Signed-off-by: Jiri Slaby Cc: Andi Kleen Cc: hpa@zytor.com Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- Documentation/x86_64/mm.txt | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/x86_64/mm.txt b/Documentation/x86_64/mm.txt index b89b6d2bebfa..efce75097369 100644 --- a/Documentation/x86_64/mm.txt +++ b/Documentation/x86_64/mm.txt @@ -11,9 +11,8 @@ ffffc10000000000 - ffffc1ffffffffff (=40 bits) hole ffffc20000000000 - ffffe1ffffffffff (=45 bits) vmalloc/ioremap space ffffe20000000000 - ffffe2ffffffffff (=40 bits) virtual memory map (1TB) ... unused hole ... -ffffffff80000000 - ffffffff82800000 (=40 MB) kernel text mapping, from phys 0 -... unused hole ... -ffffffff88000000 - fffffffffff00000 (=1919 MB) module mapping space +ffffffff80000000 - ffffffffa0000000 (=512 MB) kernel text mapping, from phys 0 +ffffffffa0000000 - fffffffffff00000 (=1536 MB) module mapping space The direct mapping covers all memory in the system up to the highest memory address (this means in some cases it can also include PCI memory -- cgit v1.2.3 From 95ffa2438d0e9c48779f0106b1c0eb36165e759c Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Tue, 29 Apr 2008 03:52:33 -0700 Subject: x86: mtrr cleanup for converting continuous to discrete layout, v8 some BIOS like to use continus MTRR layout, and X driver can not add WB entries for graphical cards when 4g or more RAM installed. the patch will change MTRR to discrete. mtrr_chunk_size= could be used to have smaller continuous block to hold holes. default is 256m, could be set according to size of graphics card memory. mtrr_gran_size= could be used to send smallest mtrr block to avoid run out of MTRRs v2: fix -1 for UC checking v3: default to disable, and need use enable_mtrr_cleanup to enable this feature skip the var state change warning. remove next_basek in range_to_mtrr() v4: correct warning mask. v5: CONFIG_MTRR_SANITIZER v6: fix 1g, 2g, 512 aligment with extra hole v7: gran_sizek to prevent running out of MTRRs. v8: fix hole_basek caculation caused when removing next_basek gran_sizek using when basek is 0. need to apply [PATCH] x86: fix trimming e820 with MTRR holes. right after this one. Signed-off-by: Yinghai Lu Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- Documentation/kernel-parameters.txt | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index e07c432c731f..44427607b7c6 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -599,6 +599,20 @@ and is between 256 and 4096 characters. It is defined in the file See drivers/char/README.epca and Documentation/digiepca.txt. + disable_mtrr_cleanup [X86] + enable_mtrr_cleanup [X86] + The kernel tries to adjust MTRR layout from continuous + to discrete, to make X server driver able to add WB + entry later. This parameter enables/disables that. + + mtrr_chunk_size=nn[KMG] [X86] + used for mtrr cleanup. It is largest continous chunk + that could hold holes aka. UC entries. + + mtrr_gran_size=nn[KMG] [X86] + used for mtrr cleanup. It is granity of mtrr block. + Big value could prevent small alignment use up MTRRs. + disable_mtrr_trim [X86, Intel and AMD only] By default the kernel will trim any uncacheable memory out of your available memory pool based on -- cgit v1.2.3 From 12031a624af7816ec7660b82be648aa3703b4ebe Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Fri, 2 May 2008 02:40:22 -0700 Subject: x86: mtrr cleanup for converting continuous to discrete - auto detect v4 Loop through mtrr chunk_size and gran_size from 1M to 2G to find out the optimal value so user does not need to add mtrr_chunk_size and mtrr_gran_size to the kernel command line. If optimal value is not found, print out all list to help select less optimal value. Add mtrr_spare_reg_nr= so user could set 2 instead of 1, if the card need more entries. v2: find the one with more spare entries v3: fix hole_basek offset v4: tight the compare between range and range_new loop stop with 4g Signed-off-by: Yinghai Lu Cc: Andrew Morton Cc: Gabriel C Cc: Mika Fischer Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- Documentation/kernel-parameters.txt | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 44427607b7c6..2000977af776 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -610,8 +610,17 @@ and is between 256 and 4096 characters. It is defined in the file that could hold holes aka. UC entries. mtrr_gran_size=nn[KMG] [X86] - used for mtrr cleanup. It is granity of mtrr block. - Big value could prevent small alignment use up MTRRs. + Used for mtrr cleanup. It is granularity of mtrr block. + Default is 1. + Large value could prevent small alignment from + using up MTRRs. + + mtrr_spare_reg_nr=n [X86] + Format: + Range: 0,7 : spare reg number + Default : 1 + Used for mtrr cleanup. It is spare mtrr entries number. + Set to 2 or more if your graphical card needs more. disable_mtrr_trim [X86, Intel and AMD only] By default the kernel will trim any uncacheable -- cgit v1.2.3 From 62cf872a8eec1f11aacbec0ac3fe3698bfa9b403 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 20 May 2008 12:15:15 +0200 Subject: [ALSA] Replace CONFIG_SND_DEBUG_DETECT with CONFIG_SND_DEBUG_VERBOSE Replace CONFIG_SND_DEBUG_DETECT with CONFIG_SND_DEBUG_VERBOSE to represent its meaning more better. This config isn't provided only for the detection but for more verbose debug prints in general. Signed-off-by: Takashi Iwai --- Documentation/sound/alsa/ALSA-Configuration.txt | 2 +- Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt index 0bbee38acd26..e59569462cb9 100644 --- a/Documentation/sound/alsa/ALSA-Configuration.txt +++ b/Documentation/sound/alsa/ALSA-Configuration.txt @@ -1091,7 +1091,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. This occurs when the access to non-existing or non-working codec slot (likely a modem one) causes a stall of the communication via HD-audio bus. You can see which codec slots are probed by enabling - CONFIG_SND_DEBUG_DETECT, or simply from the file name of the codec + CONFIG_SND_DEBUG_VERBOSE, or simply from the file name of the codec proc files. Then limit the slots to probe by probe_mask option. For example, probe_mask=1 means to probe only the first slot, and probe_mask=4 means only the third slot. diff --git a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl index b03df4d4795c..e13c4e67029f 100644 --- a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl +++ b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl @@ -6127,8 +6127,8 @@ struct _snd_pcm_runtime { snd_printdd() is compiled in only when - CONFIG_SND_DEBUG_DETECT is set. Please note - that DEBUG_DETECT is not set as default + CONFIG_SND_DEBUG_VERBOSE is set. Please note + that CONFIG_SND_DEBUG_VERBOSE is not set as default even if you configure the alsa-driver with option. You need to give explicitly option instead. -- cgit v1.2.3 From 6dda9f4a95905f2b38e79e3737da5e25397e6acb Mon Sep 17 00:00:00 2001 From: Kailang Yang Date: Tue, 27 May 2008 12:05:31 +0200 Subject: [ALSA] hda - Add ALC663 support Added the support of ALC663 codec, including specific models for ASUS M51VA, ASUS G71V, ASUS H13 and ASUS G50V. Signed-off-by: Kailang Yang Signed-off-by: Takashi Iwai --- Documentation/sound/alsa/ALSA-Configuration.txt | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt index e59569462cb9..f48939e97aba 100644 --- a/Documentation/sound/alsa/ALSA-Configuration.txt +++ b/Documentation/sound/alsa/ALSA-Configuration.txt @@ -845,7 +845,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. ALC269 basic Basic preset - ALC662 + ALC662/663 3stack-dig 3-stack (2-channel) with SPDIF 3stack-6ch 3-stack (6-channel) 3stack-6ch-dig 3-stack (6-channel) with SPDIF @@ -853,6 +853,10 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. lenovo-101e Lenovo laptop eeepc-p701 ASUS Eeepc P701 eeepc-ep20 ASUS Eeepc EP20 + m51va ASUS M51VA + g71v ASUS G71V + h13 ASUS H13 + g50v ASUS G50V auto auto-config reading BIOS (default) ALC882/885 -- cgit v1.2.3 From a93bbaa77ea61c6bad684263a65f812b31bf9791 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 27 May 2008 17:59:24 +0200 Subject: [ALSA] Improve the slots option handling Fix and improve the slots option handling. The sound core tries to find the slot with the given module name first and assign if it's still available. If all pre-given slots are unavailable, then try to find another free slot. Also, when a module name begins with '!', it means the negative match: the slot will be given for any modules but that one. Signed-off-by: Takashi Iwai --- Documentation/sound/alsa/ALSA-Configuration.txt | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'Documentation') diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt index f48939e97aba..529073dea196 100644 --- a/Documentation/sound/alsa/ALSA-Configuration.txt +++ b/Documentation/sound/alsa/ALSA-Configuration.txt @@ -2271,6 +2271,10 @@ case above again, the first two slots are already reserved. If any other driver (e.g. snd-usb-audio) is loaded before snd-interwave or snd-ens1371, it will be assigned to the third or later slot. +When a module name is given with '!', the slot will be given for any +modules but that name. For example, "slots=!snd-pcsp" will reserve +the first slot for any modules but snd-pcsp. + ALSA PCM devices to OSS devices mapping ======================================= -- cgit v1.2.3 From 4039feb5bae72a5fed9ba6bc1a9cfd8dfe0a8613 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Fri, 30 May 2008 17:16:20 -0700 Subject: x86: update Documentation/i386/boot.txt Document QUIET_FLAG, correct the definition of several fields, make it clear this applies to the entire x86 architecture, not just i386. Signed-off-by: H. Peter Anvin --- Documentation/i386/boot.txt | 79 ++++++++++++++++++++++++++------------------- 1 file changed, 46 insertions(+), 33 deletions(-) (limited to 'Documentation') diff --git a/Documentation/i386/boot.txt b/Documentation/i386/boot.txt index 95ad15c3b01f..147bfe511cdd 100644 --- a/Documentation/i386/boot.txt +++ b/Documentation/i386/boot.txt @@ -1,17 +1,14 @@ - THE LINUX/I386 BOOT PROTOCOL - ---------------------------- + THE LINUX/x86 BOOT PROTOCOL + --------------------------- - H. Peter Anvin - Last update 2007-05-23 - -On the i386 platform, the Linux kernel uses a rather complicated boot +On the x86 platform, the Linux kernel uses a rather complicated boot convention. This has evolved partially due to historical aspects, as well as the desire in the early days to have the kernel itself be a bootable image, the complicated PC memory model and due to changed expectations in the PC industry caused by the effective demise of real-mode DOS as a mainstream operating system. -Currently, the following versions of the Linux/i386 boot protocol exist. +Currently, the following versions of the Linux/x86 boot protocol exist. Old kernels: zImage/Image support only. Some very early kernels may not even support a command line. @@ -372,10 +369,17 @@ Protocol: 2.00+ - If 0, the protected-mode code is loaded at 0x10000. - If 1, the protected-mode code is loaded at 0x100000. + Bit 5 (write): QUIET_FLAG + - If 0, print early messages. + - If 1, suppress early messages. + This requests to the kernel (decompressor and early + kernel) to not write early messages that require + accessing the display hardware directly. + Bit 6 (write): KEEP_SEGMENTS Protocol: 2.07+ - - if 0, reload the segment registers in the 32bit entry point. - - if 1, do not reload the segment registers in the 32bit entry point. + - If 0, reload the segment registers in the 32bit entry point. + - If 1, do not reload the segment registers in the 32bit entry point. Assume that %cs %ds %ss %es are all set to flat segments with a base of 0 (or the equivalent for their environment). @@ -504,7 +508,7 @@ Protocol: 2.06+ maximum size was 255. Field name: hardware_subarch -Type: write +Type: write (optional, defaults to x86/PC) Offset/size: 0x23c/4 Protocol: 2.07+ @@ -520,11 +524,13 @@ Protocol: 2.07+ 0x00000002 Xen Field name: hardware_subarch_data -Type: write +Type: write (subarch-dependent) Offset/size: 0x240/8 Protocol: 2.07+ A pointer to data that is specific to hardware subarch + This field is currently unused for the default x86/PC environment, + do not modify. Field name: payload_offset Type: read @@ -545,6 +551,34 @@ Protocol: 2.08+ The length of the payload. +Field name: setup_data +Type: write (special) +Offset/size: 0x250/8 +Protocol: 2.09+ + + The 64-bit physical pointer to NULL terminated single linked list of + struct setup_data. This is used to define a more extensible boot + parameters passing mechanism. The definition of struct setup_data is + as follow: + + struct setup_data { + u64 next; + u32 type; + u32 len; + u8 data[0]; + }; + + Where, the next is a 64-bit physical pointer to the next node of + linked list, the next field of the last node is 0; the type is used + to identify the contents of data; the len is the length of data + field; the data holds the real payload. + + This list may be modified at a number of points during the bootup + process. Therefore, when modifying this list one should always make + sure to consider the case where the linked list already contains + entries. + + **** THE IMAGE CHECKSUM From boot protocol version 2.08 onwards the CRC-32 is calculated over @@ -553,6 +587,7 @@ initial remainder of 0xffffffff. The checksum is appended to the file; therefore the CRC of the file up to the limit specified in the syssize field of the header is always 0. + **** THE KERNEL COMMAND LINE The kernel command line has become an important way for the boot @@ -584,28 +619,6 @@ command line is entered using the following protocol: covered by setup_move_size, so you may need to adjust this field. -Field name: setup_data -Type: write (obligatory) -Offset/size: 0x250/8 -Protocol: 2.09+ - - The 64-bit physical pointer to NULL terminated single linked list of - struct setup_data. This is used to define a more extensible boot - parameters passing mechanism. The definition of struct setup_data is - as follow: - - struct setup_data { - u64 next; - u32 type; - u32 len; - u8 data[0]; - }; - - Where, the next is a 64-bit physical pointer to the next node of - linked list, the next field of the last node is 0; the type is used - to identify the contents of data; the len is the length of data - field; the data holds the real payload. - **** MEMORY LAYOUT OF THE REAL-MODE CODE -- cgit v1.2.3 From 23deb06821442506615f34bd92ccd6a2422629d7 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Fri, 30 May 2008 17:19:03 -0700 Subject: x86: move x86-specific documentation into Documentation/x86 The current organization of the x86 documentation makes it appear as if the "i386" documentation doesn't apply to x86-64, which is does. Thus, move that documentation into Documentation/x86, and move the x86-64-specific stuff into Documentation/x86/x86_64 with the eventual goal to move stuff that isn't actually 64-bit specific back into Documentation/x86. Signed-off-by: H. Peter Anvin --- Documentation/i386/IO-APIC.txt | 119 ---- Documentation/i386/boot.txt | 900 ------------------------- Documentation/i386/usb-legacy-support.txt | 44 -- Documentation/i386/zero-page.txt | 31 - Documentation/x86/i386/IO-APIC.txt | 119 ++++ Documentation/x86/i386/boot.txt | 900 +++++++++++++++++++++++++ Documentation/x86/i386/usb-legacy-support.txt | 44 ++ Documentation/x86/i386/zero-page.txt | 31 + Documentation/x86/x86_64/00-INDEX | 16 + Documentation/x86/x86_64/boot-options.txt | 314 +++++++++ Documentation/x86/x86_64/cpu-hotplug-spec | 21 + Documentation/x86/x86_64/fake-numa-for-cpusets | 66 ++ Documentation/x86/x86_64/kernel-stacks | 99 +++ Documentation/x86/x86_64/machinecheck | 77 +++ Documentation/x86/x86_64/mm.txt | 29 + Documentation/x86/x86_64/uefi.txt | 38 ++ Documentation/x86_64/00-INDEX | 16 - Documentation/x86_64/boot-options.txt | 314 --------- Documentation/x86_64/cpu-hotplug-spec | 21 - Documentation/x86_64/fake-numa-for-cpusets | 66 -- Documentation/x86_64/kernel-stacks | 99 --- Documentation/x86_64/machinecheck | 77 --- Documentation/x86_64/mm.txt | 29 - Documentation/x86_64/uefi.txt | 38 -- 24 files changed, 1754 insertions(+), 1754 deletions(-) delete mode 100644 Documentation/i386/IO-APIC.txt delete mode 100644 Documentation/i386/boot.txt delete mode 100644 Documentation/i386/usb-legacy-support.txt delete mode 100644 Documentation/i386/zero-page.txt create mode 100644 Documentation/x86/i386/IO-APIC.txt create mode 100644 Documentation/x86/i386/boot.txt create mode 100644 Documentation/x86/i386/usb-legacy-support.txt create mode 100644 Documentation/x86/i386/zero-page.txt create mode 100644 Documentation/x86/x86_64/00-INDEX create mode 100644 Documentation/x86/x86_64/boot-options.txt create mode 100644 Documentation/x86/x86_64/cpu-hotplug-spec create mode 100644 Documentation/x86/x86_64/fake-numa-for-cpusets create mode 100644 Documentation/x86/x86_64/kernel-stacks create mode 100644 Documentation/x86/x86_64/machinecheck create mode 100644 Documentation/x86/x86_64/mm.txt create mode 100644 Documentation/x86/x86_64/uefi.txt delete mode 100644 Documentation/x86_64/00-INDEX delete mode 100644 Documentation/x86_64/boot-options.txt delete mode 100644 Documentation/x86_64/cpu-hotplug-spec delete mode 100644 Documentation/x86_64/fake-numa-for-cpusets delete mode 100644 Documentation/x86_64/kernel-stacks delete mode 100644 Documentation/x86_64/machinecheck delete mode 100644 Documentation/x86_64/mm.txt delete mode 100644 Documentation/x86_64/uefi.txt (limited to 'Documentation') diff --git a/Documentation/i386/IO-APIC.txt b/Documentation/i386/IO-APIC.txt deleted file mode 100644 index 30b4c714fbe1..000000000000 --- a/Documentation/i386/IO-APIC.txt +++ /dev/null @@ -1,119 +0,0 @@ -Most (all) Intel-MP compliant SMP boards have the so-called 'IO-APIC', -which is an enhanced interrupt controller. It enables us to route -hardware interrupts to multiple CPUs, or to CPU groups. Without an -IO-APIC, interrupts from hardware will be delivered only to the -CPU which boots the operating system (usually CPU#0). - -Linux supports all variants of compliant SMP boards, including ones with -multiple IO-APICs. Multiple IO-APICs are used in high-end servers to -distribute IRQ load further. - -There are (a few) known breakages in certain older boards, such bugs are -usually worked around by the kernel. If your MP-compliant SMP board does -not boot Linux, then consult the linux-smp mailing list archives first. - -If your box boots fine with enabled IO-APIC IRQs, then your -/proc/interrupts will look like this one: - - ----------------------------> - hell:~> cat /proc/interrupts - CPU0 - 0: 1360293 IO-APIC-edge timer - 1: 4 IO-APIC-edge keyboard - 2: 0 XT-PIC cascade - 13: 1 XT-PIC fpu - 14: 1448 IO-APIC-edge ide0 - 16: 28232 IO-APIC-level Intel EtherExpress Pro 10/100 Ethernet - 17: 51304 IO-APIC-level eth0 - NMI: 0 - ERR: 0 - hell:~> - <---------------------------- - -Some interrupts are still listed as 'XT PIC', but this is not a problem; -none of those IRQ sources is performance-critical. - - -In the unlikely case that your board does not create a working mp-table, -you can use the pirq= boot parameter to 'hand-construct' IRQ entries. This -is non-trivial though and cannot be automated. One sample /etc/lilo.conf -entry: - - append="pirq=15,11,10" - -The actual numbers depend on your system, on your PCI cards and on their -PCI slot position. Usually PCI slots are 'daisy chained' before they are -connected to the PCI chipset IRQ routing facility (the incoming PIRQ1-4 -lines): - - ,-. ,-. ,-. ,-. ,-. - PIRQ4 ----| |-. ,-| |-. ,-| |-. ,-| |--------| | - |S| \ / |S| \ / |S| \ / |S| |S| - PIRQ3 ----|l|-. `/---|l|-. `/---|l|-. `/---|l|--------|l| - |o| \/ |o| \/ |o| \/ |o| |o| - PIRQ2 ----|t|-./`----|t|-./`----|t|-./`----|t|--------|t| - |1| /\ |2| /\ |3| /\ |4| |5| - PIRQ1 ----| |- `----| |- `----| |- `----| |--------| | - `-' `-' `-' `-' `-' - -Every PCI card emits a PCI IRQ, which can be INTA, INTB, INTC or INTD: - - ,-. - INTD--| | - |S| - INTC--|l| - |o| - INTB--|t| - |x| - INTA--| | - `-' - -These INTA-D PCI IRQs are always 'local to the card', their real meaning -depends on which slot they are in. If you look at the daisy chaining diagram, -a card in slot4, issuing INTA IRQ, it will end up as a signal on PIRQ4 of -the PCI chipset. Most cards issue INTA, this creates optimal distribution -between the PIRQ lines. (distributing IRQ sources properly is not a -necessity, PCI IRQs can be shared at will, but it's a good for performance -to have non shared interrupts). Slot5 should be used for videocards, they -do not use interrupts normally, thus they are not daisy chained either. - -so if you have your SCSI card (IRQ11) in Slot1, Tulip card (IRQ9) in -Slot2, then you'll have to specify this pirq= line: - - append="pirq=11,9" - -the following script tries to figure out such a default pirq= line from -your PCI configuration: - - echo -n pirq=; echo `scanpci | grep T_L | cut -c56-` | sed 's/ /,/g' - -note that this script wont work if you have skipped a few slots or if your -board does not do default daisy-chaining. (or the IO-APIC has the PIRQ pins -connected in some strange way). E.g. if in the above case you have your SCSI -card (IRQ11) in Slot3, and have Slot1 empty: - - append="pirq=0,9,11" - -[value '0' is a generic 'placeholder', reserved for empty (or non-IRQ emitting) -slots.] - -Generally, it's always possible to find out the correct pirq= settings, just -permute all IRQ numbers properly ... it will take some time though. An -'incorrect' pirq line will cause the booting process to hang, or a device -won't function properly (e.g. if it's inserted as a module). - -If you have 2 PCI buses, then you can use up to 8 pirq values, although such -boards tend to have a good configuration. - -Be prepared that it might happen that you need some strange pirq line: - - append="pirq=0,0,0,0,0,0,9,11" - -Use smart trial-and-error techniques to find out the correct pirq line ... - -Good luck and mail to linux-smp@vger.kernel.org or -linux-kernel@vger.kernel.org if you have any problems that are not covered -by this document. - --- mingo - diff --git a/Documentation/i386/boot.txt b/Documentation/i386/boot.txt deleted file mode 100644 index 147bfe511cdd..000000000000 --- a/Documentation/i386/boot.txt +++ /dev/null @@ -1,900 +0,0 @@ - THE LINUX/x86 BOOT PROTOCOL - --------------------------- - -On the x86 platform, the Linux kernel uses a rather complicated boot -convention. This has evolved partially due to historical aspects, as -well as the desire in the early days to have the kernel itself be a -bootable image, the complicated PC memory model and due to changed -expectations in the PC industry caused by the effective demise of -real-mode DOS as a mainstream operating system. - -Currently, the following versions of the Linux/x86 boot protocol exist. - -Old kernels: zImage/Image support only. Some very early kernels - may not even support a command line. - -Protocol 2.00: (Kernel 1.3.73) Added bzImage and initrd support, as - well as a formalized way to communicate between the - boot loader and the kernel. setup.S made relocatable, - although the traditional setup area still assumed - writable. - -Protocol 2.01: (Kernel 1.3.76) Added a heap overrun warning. - -Protocol 2.02: (Kernel 2.4.0-test3-pre3) New command line protocol. - Lower the conventional memory ceiling. No overwrite - of the traditional setup area, thus making booting - safe for systems which use the EBDA from SMM or 32-bit - BIOS entry points. zImage deprecated but still - supported. - -Protocol 2.03: (Kernel 2.4.18-pre1) Explicitly makes the highest possible - initrd address available to the bootloader. - -Protocol 2.04: (Kernel 2.6.14) Extend the syssize field to four bytes. - -Protocol 2.05: (Kernel 2.6.20) Make protected mode kernel relocatable. - Introduce relocatable_kernel and kernel_alignment fields. - -Protocol 2.06: (Kernel 2.6.22) Added a field that contains the size of - the boot command line. - -Protocol 2.07: (Kernel 2.6.24) Added paravirtualised boot protocol. - Introduced hardware_subarch and hardware_subarch_data - and KEEP_SEGMENTS flag in load_flags. - -Protocol 2.08: (Kernel 2.6.26) Added crc32 checksum and ELF format - payload. Introduced payload_offset and payload length - fields to aid in locating the payload. - -Protocol 2.09: (Kernel 2.6.26) Added a field of 64-bit physical - pointer to single linked list of struct setup_data. - -**** MEMORY LAYOUT - -The traditional memory map for the kernel loader, used for Image or -zImage kernels, typically looks like: - - | | -0A0000 +------------------------+ - | Reserved for BIOS | Do not use. Reserved for BIOS EBDA. -09A000 +------------------------+ - | Command line | - | Stack/heap | For use by the kernel real-mode code. -098000 +------------------------+ - | Kernel setup | The kernel real-mode code. -090200 +------------------------+ - | Kernel boot sector | The kernel legacy boot sector. -090000 +------------------------+ - | Protected-mode kernel | The bulk of the kernel image. -010000 +------------------------+ - | Boot loader | <- Boot sector entry point 0000:7C00 -001000 +------------------------+ - | Reserved for MBR/BIOS | -000800 +------------------------+ - | Typically used by MBR | -000600 +------------------------+ - | BIOS use only | -000000 +------------------------+ - - -When using bzImage, the protected-mode kernel was relocated to -0x100000 ("high memory"), and the kernel real-mode block (boot sector, -setup, and stack/heap) was made relocatable to any address between -0x10000 and end of low memory. Unfortunately, in protocols 2.00 and -2.01 the 0x90000+ memory range is still used internally by the kernel; -the 2.02 protocol resolves that problem. - -It is desirable to keep the "memory ceiling" -- the highest point in -low memory touched by the boot loader -- as low as possible, since -some newer BIOSes have begun to allocate some rather large amounts of -memory, called the Extended BIOS Data Area, near the top of low -memory. The boot loader should use the "INT 12h" BIOS call to verify -how much low memory is available. - -Unfortunately, if INT 12h reports that the amount of memory is too -low, there is usually nothing the boot loader can do but to report an -error to the user. The boot loader should therefore be designed to -take up as little space in low memory as it reasonably can. For -zImage or old bzImage kernels, which need data written into the -0x90000 segment, the boot loader should make sure not to use memory -above the 0x9A000 point; too many BIOSes will break above that point. - -For a modern bzImage kernel with boot protocol version >= 2.02, a -memory layout like the following is suggested: - - ~ ~ - | Protected-mode kernel | -100000 +------------------------+ - | I/O memory hole | -0A0000 +------------------------+ - | Reserved for BIOS | Leave as much as possible unused - ~ ~ - | Command line | (Can also be below the X+10000 mark) -X+10000 +------------------------+ - | Stack/heap | For use by the kernel real-mode code. -X+08000 +------------------------+ - | Kernel setup | The kernel real-mode code. - | Kernel boot sector | The kernel legacy boot sector. -X +------------------------+ - | Boot loader | <- Boot sector entry point 0000:7C00 -001000 +------------------------+ - | Reserved for MBR/BIOS | -000800 +------------------------+ - | Typically used by MBR | -000600 +------------------------+ - | BIOS use only | -000000 +------------------------+ - -... where the address X is as low as the design of the boot loader -permits. - - -**** THE REAL-MODE KERNEL HEADER - -In the following text, and anywhere in the kernel boot sequence, "a -sector" refers to 512 bytes. It is independent of the actual sector -size of the underlying medium. - -The first step in loading a Linux kernel should be to load the -real-mode code (boot sector and setup code) and then examine the -following header at offset 0x01f1. The real-mode code can total up to -32K, although the boot loader may choose to load only the first two -sectors (1K) and then examine the bootup sector size. - -The header looks like: - -Offset Proto Name Meaning -/Size - -01F1/1 ALL(1 setup_sects The size of the setup in sectors -01F2/2 ALL root_flags If set, the root is mounted readonly -01F4/4 2.04+(2 syssize The size of the 32-bit code in 16-byte paras -01F8/2 ALL ram_size DO NOT USE - for bootsect.S use only -01FA/2 ALL vid_mode Video mode control -01FC/2 ALL root_dev Default root device number -01FE/2 ALL boot_flag 0xAA55 magic number -0200/2 2.00+ jump Jump instruction -0202/4 2.00+ header Magic signature "HdrS" -0206/2 2.00+ version Boot protocol version supported -0208/4 2.00+ realmode_swtch Boot loader hook (see below) -020C/2 2.00+ start_sys The load-low segment (0x1000) (obsolete) -020E/2 2.00+ kernel_version Pointer to kernel version string -0210/1 2.00+ type_of_loader Boot loader identifier -0211/1 2.00+ loadflags Boot protocol option flags -0212/2 2.00+ setup_move_size Move to high memory size (used with hooks) -0214/4 2.00+ code32_start Boot loader hook (see below) -0218/4 2.00+ ramdisk_image initrd load address (set by boot loader) -021C/4 2.00+ ramdisk_size initrd size (set by boot loader) -0220/4 2.00+ bootsect_kludge DO NOT USE - for bootsect.S use only -0224/2 2.01+ heap_end_ptr Free memory after setup end -0226/2 N/A pad1 Unused -0228/4 2.02+ cmd_line_ptr 32-bit pointer to the kernel command line -022C/4 2.03+ initrd_addr_max Highest legal initrd address -0230/4 2.05+ kernel_alignment Physical addr alignment required for kernel -0234/1 2.05+ relocatable_kernel Whether kernel is relocatable or not -0235/3 N/A pad2 Unused -0238/4 2.06+ cmdline_size Maximum size of the kernel command line -023C/4 2.07+ hardware_subarch Hardware subarchitecture -0240/8 2.07+ hardware_subarch_data Subarchitecture-specific data -0248/4 2.08+ payload_offset Offset of kernel payload -024C/4 2.08+ payload_length Length of kernel payload -0250/8 2.09+ setup_data 64-bit physical pointer to linked list - of struct setup_data - -(1) For backwards compatibility, if the setup_sects field contains 0, the - real value is 4. - -(2) For boot protocol prior to 2.04, the upper two bytes of the syssize - field are unusable, which means the size of a bzImage kernel - cannot be determined. - -If the "HdrS" (0x53726448) magic number is not found at offset 0x202, -the boot protocol version is "old". Loading an old kernel, the -following parameters should be assumed: - - Image type = zImage - initrd not supported - Real-mode kernel must be located at 0x90000. - -Otherwise, the "version" field contains the protocol version, -e.g. protocol version 2.01 will contain 0x0201 in this field. When -setting fields in the header, you must make sure only to set fields -supported by the protocol version in use. - - -**** DETAILS OF HEADER FIELDS - -For each field, some are information from the kernel to the bootloader -("read"), some are expected to be filled out by the bootloader -("write"), and some are expected to be read and modified by the -bootloader ("modify"). - -All general purpose boot loaders should write the fields marked -(obligatory). Boot loaders who want to load the kernel at a -nonstandard address should fill in the fields marked (reloc); other -boot loaders can ignore those fields. - -The byte order of all fields is littleendian (this is x86, after all.) - -Field name: setup_sects -Type: read -Offset/size: 0x1f1/1 -Protocol: ALL - - The size of the setup code in 512-byte sectors. If this field is - 0, the real value is 4. The real-mode code consists of the boot - sector (always one 512-byte sector) plus the setup code. - -Field name: root_flags -Type: modify (optional) -Offset/size: 0x1f2/2 -Protocol: ALL - - If this field is nonzero, the root defaults to readonly. The use of - this field is deprecated; use the "ro" or "rw" options on the - command line instead. - -Field name: syssize -Type: read -Offset/size: 0x1f4/4 (protocol 2.04+) 0x1f4/2 (protocol ALL) -Protocol: 2.04+ - - The size of the protected-mode code in units of 16-byte paragraphs. - For protocol versions older than 2.04 this field is only two bytes - wide, and therefore cannot be trusted for the size of a kernel if - the LOAD_HIGH flag is set. - -Field name: ram_size -Type: kernel internal -Offset/size: 0x1f8/2 -Protocol: ALL - - This field is obsolete. - -Field name: vid_mode -Type: modify (obligatory) -Offset/size: 0x1fa/2 - - Please see the section on SPECIAL COMMAND LINE OPTIONS. - -Field name: root_dev -Type: modify (optional) -Offset/size: 0x1fc/2 -Protocol: ALL - - The default root device device number. The use of this field is - deprecated, use the "root=" option on the command line instead. - -Field name: boot_flag -Type: read -Offset/size: 0x1fe/2 -Protocol: ALL - - Contains 0xAA55. This is the closest thing old Linux kernels have - to a magic number. - -Field name: jump -Type: read -Offset/size: 0x200/2 -Protocol: 2.00+ - - Contains an x86 jump instruction, 0xEB followed by a signed offset - relative to byte 0x202. This can be used to determine the size of - the header. - -Field name: header -Type: read -Offset/size: 0x202/4 -Protocol: 2.00+ - - Contains the magic number "HdrS" (0x53726448). - -Field name: version -Type: read -Offset/size: 0x206/2 -Protocol: 2.00+ - - Contains the boot protocol version, in (major << 8)+minor format, - e.g. 0x0204 for version 2.04, and 0x0a11 for a hypothetical version - 10.17. - -Field name: readmode_swtch -Type: modify (optional) -Offset/size: 0x208/4 -Protocol: 2.00+ - - Boot loader hook (see ADVANCED BOOT LOADER HOOKS below.) - -Field name: start_sys -Type: read -Offset/size: 0x20c/4 -Protocol: 2.00+ - - The load low segment (0x1000). Obsolete. - -Field name: kernel_version -Type: read -Offset/size: 0x20e/2 -Protocol: 2.00+ - - If set to a nonzero value, contains a pointer to a NUL-terminated - human-readable kernel version number string, less 0x200. This can - be used to display the kernel version to the user. This value - should be less than (0x200*setup_sects). - - For example, if this value is set to 0x1c00, the kernel version - number string can be found at offset 0x1e00 in the kernel file. - This is a valid value if and only if the "setup_sects" field - contains the value 15 or higher, as: - - 0x1c00 < 15*0x200 (= 0x1e00) but - 0x1c00 >= 14*0x200 (= 0x1c00) - - 0x1c00 >> 9 = 14, so the minimum value for setup_secs is 15. - -Field name: type_of_loader -Type: write (obligatory) -Offset/size: 0x210/1 -Protocol: 2.00+ - - If your boot loader has an assigned id (see table below), enter - 0xTV here, where T is an identifier for the boot loader and V is - a version number. Otherwise, enter 0xFF here. - - Assigned boot loader ids: - 0 LILO (0x00 reserved for pre-2.00 bootloader) - 1 Loadlin - 2 bootsect-loader (0x20, all other values reserved) - 3 SYSLINUX - 4 EtherBoot - 5 ELILO - 7 GRuB - 8 U-BOOT - 9 Xen - A Gujin - B Qemu - - Please contact if you need a bootloader ID - value assigned. - -Field name: loadflags -Type: modify (obligatory) -Offset/size: 0x211/1 -Protocol: 2.00+ - - This field is a bitmask. - - Bit 0 (read): LOADED_HIGH - - If 0, the protected-mode code is loaded at 0x10000. - - If 1, the protected-mode code is loaded at 0x100000. - - Bit 5 (write): QUIET_FLAG - - If 0, print early messages. - - If 1, suppress early messages. - This requests to the kernel (decompressor and early - kernel) to not write early messages that require - accessing the display hardware directly. - - Bit 6 (write): KEEP_SEGMENTS - Protocol: 2.07+ - - If 0, reload the segment registers in the 32bit entry point. - - If 1, do not reload the segment registers in the 32bit entry point. - Assume that %cs %ds %ss %es are all set to flat segments with - a base of 0 (or the equivalent for their environment). - - Bit 7 (write): CAN_USE_HEAP - Set this bit to 1 to indicate that the value entered in the - heap_end_ptr is valid. If this field is clear, some setup code - functionality will be disabled. - -Field name: setup_move_size -Type: modify (obligatory) -Offset/size: 0x212/2 -Protocol: 2.00-2.01 - - When using protocol 2.00 or 2.01, if the real mode kernel is not - loaded at 0x90000, it gets moved there later in the loading - sequence. Fill in this field if you want additional data (such as - the kernel command line) moved in addition to the real-mode kernel - itself. - - The unit is bytes starting with the beginning of the boot sector. - - This field is can be ignored when the protocol is 2.02 or higher, or - if the real-mode code is loaded at 0x90000. - -Field name: code32_start -Type: modify (optional, reloc) -Offset/size: 0x214/4 -Protocol: 2.00+ - - The address to jump to in protected mode. This defaults to the load - address of the kernel, and can be used by the boot loader to - determine the proper load address. - - This field can be modified for two purposes: - - 1. as a boot loader hook (see ADVANCED BOOT LOADER HOOKS below.) - - 2. if a bootloader which does not install a hook loads a - relocatable kernel at a nonstandard address it will have to modify - this field to point to the load address. - -Field name: ramdisk_image -Type: write (obligatory) -Offset/size: 0x218/4 -Protocol: 2.00+ - - The 32-bit linear address of the initial ramdisk or ramfs. Leave at - zero if there is no initial ramdisk/ramfs. - -Field name: ramdisk_size -Type: write (obligatory) -Offset/size: 0x21c/4 -Protocol: 2.00+ - - Size of the initial ramdisk or ramfs. Leave at zero if there is no - initial ramdisk/ramfs. - -Field name: bootsect_kludge -Type: kernel internal -Offset/size: 0x220/4 -Protocol: 2.00+ - - This field is obsolete. - -Field name: heap_end_ptr -Type: write (obligatory) -Offset/size: 0x224/2 -Protocol: 2.01+ - - Set this field to the offset (from the beginning of the real-mode - code) of the end of the setup stack/heap, minus 0x0200. - -Field name: cmd_line_ptr -Type: write (obligatory) -Offset/size: 0x228/4 -Protocol: 2.02+ - - Set this field to the linear address of the kernel command line. - The kernel command line can be located anywhere between the end of - the setup heap and 0xA0000; it does not have to be located in the - same 64K segment as the real-mode code itself. - - Fill in this field even if your boot loader does not support a - command line, in which case you can point this to an empty string - (or better yet, to the string "auto".) If this field is left at - zero, the kernel will assume that your boot loader does not support - the 2.02+ protocol. - -Field name: initrd_addr_max -Type: read -Offset/size: 0x22c/4 -Protocol: 2.03+ - - The maximum address that may be occupied by the initial - ramdisk/ramfs contents. For boot protocols 2.02 or earlier, this - field is not present, and the maximum address is 0x37FFFFFF. (This - address is defined as the address of the highest safe byte, so if - your ramdisk is exactly 131072 bytes long and this field is - 0x37FFFFFF, you can start your ramdisk at 0x37FE0000.) - -Field name: kernel_alignment -Type: read (reloc) -Offset/size: 0x230/4 -Protocol: 2.05+ - - Alignment unit required by the kernel (if relocatable_kernel is true.) - -Field name: relocatable_kernel -Type: read (reloc) -Offset/size: 0x234/1 -Protocol: 2.05+ - - If this field is nonzero, the protected-mode part of the kernel can - be loaded at any address that satisfies the kernel_alignment field. - After loading, the boot loader must set the code32_start field to - point to the loaded code, or to a boot loader hook. - -Field name: cmdline_size -Type: read -Offset/size: 0x238/4 -Protocol: 2.06+ - - The maximum size of the command line without the terminating - zero. This means that the command line can contain at most - cmdline_size characters. With protocol version 2.05 and earlier, the - maximum size was 255. - -Field name: hardware_subarch -Type: write (optional, defaults to x86/PC) -Offset/size: 0x23c/4 -Protocol: 2.07+ - - In a paravirtualized environment the hardware low level architectural - pieces such as interrupt handling, page table handling, and - accessing process control registers needs to be done differently. - - This field allows the bootloader to inform the kernel we are in one - one of those environments. - - 0x00000000 The default x86/PC environment - 0x00000001 lguest - 0x00000002 Xen - -Field name: hardware_subarch_data -Type: write (subarch-dependent) -Offset/size: 0x240/8 -Protocol: 2.07+ - - A pointer to data that is specific to hardware subarch - This field is currently unused for the default x86/PC environment, - do not modify. - -Field name: payload_offset -Type: read -Offset/size: 0x248/4 -Protocol: 2.08+ - - If non-zero then this field contains the offset from the end of the - real-mode code to the payload. - - The payload may be compressed. The format of both the compressed and - uncompressed data should be determined using the standard magic - numbers. Currently only gzip compressed ELF is used. - -Field name: payload_length -Type: read -Offset/size: 0x24c/4 -Protocol: 2.08+ - - The length of the payload. - -Field name: setup_data -Type: write (special) -Offset/size: 0x250/8 -Protocol: 2.09+ - - The 64-bit physical pointer to NULL terminated single linked list of - struct setup_data. This is used to define a more extensible boot - parameters passing mechanism. The definition of struct setup_data is - as follow: - - struct setup_data { - u64 next; - u32 type; - u32 len; - u8 data[0]; - }; - - Where, the next is a 64-bit physical pointer to the next node of - linked list, the next field of the last node is 0; the type is used - to identify the contents of data; the len is the length of data - field; the data holds the real payload. - - This list may be modified at a number of points during the bootup - process. Therefore, when modifying this list one should always make - sure to consider the case where the linked list already contains - entries. - - -**** THE IMAGE CHECKSUM - -From boot protocol version 2.08 onwards the CRC-32 is calculated over -the entire file using the characteristic polynomial 0x04C11DB7 and an -initial remainder of 0xffffffff. The checksum is appended to the -file; therefore the CRC of the file up to the limit specified in the -syssize field of the header is always 0. - - -**** THE KERNEL COMMAND LINE - -The kernel command line has become an important way for the boot -loader to communicate with the kernel. Some of its options are also -relevant to the boot loader itself, see "special command line options" -below. - -The kernel command line is a null-terminated string. The maximum -length can be retrieved from the field cmdline_size. Before protocol -version 2.06, the maximum was 255 characters. A string that is too -long will be automatically truncated by the kernel. - -If the boot protocol version is 2.02 or later, the address of the -kernel command line is given by the header field cmd_line_ptr (see -above.) This address can be anywhere between the end of the setup -heap and 0xA0000. - -If the protocol version is *not* 2.02 or higher, the kernel -command line is entered using the following protocol: - - At offset 0x0020 (word), "cmd_line_magic", enter the magic - number 0xA33F. - - At offset 0x0022 (word), "cmd_line_offset", enter the offset - of the kernel command line (relative to the start of the - real-mode kernel). - - The kernel command line *must* be within the memory region - covered by setup_move_size, so you may need to adjust this - field. - - -**** MEMORY LAYOUT OF THE REAL-MODE CODE - -The real-mode code requires a stack/heap to be set up, as well as -memory allocated for the kernel command line. This needs to be done -in the real-mode accessible memory in bottom megabyte. - -It should be noted that modern machines often have a sizable Extended -BIOS Data Area (EBDA). As a result, it is advisable to use as little -of the low megabyte as possible. - -Unfortunately, under the following circumstances the 0x90000 memory -segment has to be used: - - - When loading a zImage kernel ((loadflags & 0x01) == 0). - - When loading a 2.01 or earlier boot protocol kernel. - - -> For the 2.00 and 2.01 boot protocols, the real-mode code - can be loaded at another address, but it is internally - relocated to 0x90000. For the "old" protocol, the - real-mode code must be loaded at 0x90000. - -When loading at 0x90000, avoid using memory above 0x9a000. - -For boot protocol 2.02 or higher, the command line does not have to be -located in the same 64K segment as the real-mode setup code; it is -thus permitted to give the stack/heap the full 64K segment and locate -the command line above it. - -The kernel command line should not be located below the real-mode -code, nor should it be located in high memory. - - -**** SAMPLE BOOT CONFIGURATION - -As a sample configuration, assume the following layout of the real -mode segment: - - When loading below 0x90000, use the entire segment: - - 0x0000-0x7fff Real mode kernel - 0x8000-0xdfff Stack and heap - 0xe000-0xffff Kernel command line - - When loading at 0x90000 OR the protocol version is 2.01 or earlier: - - 0x0000-0x7fff Real mode kernel - 0x8000-0x97ff Stack and heap - 0x9800-0x9fff Kernel command line - -Such a boot loader should enter the following fields in the header: - - unsigned long base_ptr; /* base address for real-mode segment */ - - if ( setup_sects == 0 ) { - setup_sects = 4; - } - - if ( protocol >= 0x0200 ) { - type_of_loader = ; - if ( loading_initrd ) { - ramdisk_image = ; - ramdisk_size = ; - } - - if ( protocol >= 0x0202 && loadflags & 0x01 ) - heap_end = 0xe000; - else - heap_end = 0x9800; - - if ( protocol >= 0x0201 ) { - heap_end_ptr = heap_end - 0x200; - loadflags |= 0x80; /* CAN_USE_HEAP */ - } - - if ( protocol >= 0x0202 ) { - cmd_line_ptr = base_ptr + heap_end; - strcpy(cmd_line_ptr, cmdline); - } else { - cmd_line_magic = 0xA33F; - cmd_line_offset = heap_end; - setup_move_size = heap_end + strlen(cmdline)+1; - strcpy(base_ptr+cmd_line_offset, cmdline); - } - } else { - /* Very old kernel */ - - heap_end = 0x9800; - - cmd_line_magic = 0xA33F; - cmd_line_offset = heap_end; - - /* A very old kernel MUST have its real-mode code - loaded at 0x90000 */ - - if ( base_ptr != 0x90000 ) { - /* Copy the real-mode kernel */ - memcpy(0x90000, base_ptr, (setup_sects+1)*512); - base_ptr = 0x90000; /* Relocated */ - } - - strcpy(0x90000+cmd_line_offset, cmdline); - - /* It is recommended to clear memory up to the 32K mark */ - memset(0x90000 + (setup_sects+1)*512, 0, - (64-(setup_sects+1))*512); - } - - -**** LOADING THE REST OF THE KERNEL - -The 32-bit (non-real-mode) kernel starts at offset (setup_sects+1)*512 -in the kernel file (again, if setup_sects == 0 the real value is 4.) -It should be loaded at address 0x10000 for Image/zImage kernels and -0x100000 for bzImage kernels. - -The kernel is a bzImage kernel if the protocol >= 2.00 and the 0x01 -bit (LOAD_HIGH) in the loadflags field is set: - - is_bzImage = (protocol >= 0x0200) && (loadflags & 0x01); - load_address = is_bzImage ? 0x100000 : 0x10000; - -Note that Image/zImage kernels can be up to 512K in size, and thus use -the entire 0x10000-0x90000 range of memory. This means it is pretty -much a requirement for these kernels to load the real-mode part at -0x90000. bzImage kernels allow much more flexibility. - - -**** SPECIAL COMMAND LINE OPTIONS - -If the command line provided by the boot loader is entered by the -user, the user may expect the following command line options to work. -They should normally not be deleted from the kernel command line even -though not all of them are actually meaningful to the kernel. Boot -loader authors who need additional command line options for the boot -loader itself should get them registered in -Documentation/kernel-parameters.txt to make sure they will not -conflict with actual kernel options now or in the future. - - vga= - here is either an integer (in C notation, either - decimal, octal, or hexadecimal) or one of the strings - "normal" (meaning 0xFFFF), "ext" (meaning 0xFFFE) or "ask" - (meaning 0xFFFD). This value should be entered into the - vid_mode field, as it is used by the kernel before the command - line is parsed. - - mem= - is an integer in C notation optionally followed by - (case insensitive) K, M, G, T, P or E (meaning << 10, << 20, - << 30, << 40, << 50 or << 60). This specifies the end of - memory to the kernel. This affects the possible placement of - an initrd, since an initrd should be placed near end of - memory. Note that this is an option to *both* the kernel and - the bootloader! - - initrd= - An initrd should be loaded. The meaning of is - obviously bootloader-dependent, and some boot loaders - (e.g. LILO) do not have such a command. - -In addition, some boot loaders add the following options to the -user-specified command line: - - BOOT_IMAGE= - The boot image which was loaded. Again, the meaning of - is obviously bootloader-dependent. - - auto - The kernel was booted without explicit user intervention. - -If these options are added by the boot loader, it is highly -recommended that they are located *first*, before the user-specified -or configuration-specified command line. Otherwise, "init=/bin/sh" -gets confused by the "auto" option. - - -**** RUNNING THE KERNEL - -The kernel is started by jumping to the kernel entry point, which is -located at *segment* offset 0x20 from the start of the real mode -kernel. This means that if you loaded your real-mode kernel code at -0x90000, the kernel entry point is 9020:0000. - -At entry, ds = es = ss should point to the start of the real-mode -kernel code (0x9000 if the code is loaded at 0x90000), sp should be -set up properly, normally pointing to the top of the heap, and -interrupts should be disabled. Furthermore, to guard against bugs in -the kernel, it is recommended that the boot loader sets fs = gs = ds = -es = ss. - -In our example from above, we would do: - - /* Note: in the case of the "old" kernel protocol, base_ptr must - be == 0x90000 at this point; see the previous sample code */ - - seg = base_ptr >> 4; - - cli(); /* Enter with interrupts disabled! */ - - /* Set up the real-mode kernel stack */ - _SS = seg; - _SP = heap_end; - - _DS = _ES = _FS = _GS = seg; - jmp_far(seg+0x20, 0); /* Run the kernel */ - -If your boot sector accesses a floppy drive, it is recommended to -switch off the floppy motor before running the kernel, since the -kernel boot leaves interrupts off and thus the motor will not be -switched off, especially if the loaded kernel has the floppy driver as -a demand-loaded module! - - -**** ADVANCED BOOT LOADER HOOKS - -If the boot loader runs in a particularly hostile environment (such as -LOADLIN, which runs under DOS) it may be impossible to follow the -standard memory location requirements. Such a boot loader may use the -following hooks that, if set, are invoked by the kernel at the -appropriate time. The use of these hooks should probably be -considered an absolutely last resort! - -IMPORTANT: All the hooks are required to preserve %esp, %ebp, %esi and -%edi across invocation. - - realmode_swtch: - A 16-bit real mode far subroutine invoked immediately before - entering protected mode. The default routine disables NMI, so - your routine should probably do so, too. - - code32_start: - A 32-bit flat-mode routine *jumped* to immediately after the - transition to protected mode, but before the kernel is - uncompressed. No segments, except CS, are guaranteed to be - set up (current kernels do, but older ones do not); you should - set them up to BOOT_DS (0x18) yourself. - - After completing your hook, you should jump to the address - that was in this field before your boot loader overwrote it - (relocated, if appropriate.) - - -**** 32-bit BOOT PROTOCOL - -For machine with some new BIOS other than legacy BIOS, such as EFI, -LinuxBIOS, etc, and kexec, the 16-bit real mode setup code in kernel -based on legacy BIOS can not be used, so a 32-bit boot protocol needs -to be defined. - -In 32-bit boot protocol, the first step in loading a Linux kernel -should be to setup the boot parameters (struct boot_params, -traditionally known as "zero page"). The memory for struct boot_params -should be allocated and initialized to all zero. Then the setup header -from offset 0x01f1 of kernel image on should be loaded into struct -boot_params and examined. The end of setup header can be calculated as -follow: - - 0x0202 + byte value at offset 0x0201 - -In addition to read/modify/write the setup header of the struct -boot_params as that of 16-bit boot protocol, the boot loader should -also fill the additional fields of the struct boot_params as that -described in zero-page.txt. - -After setupping the struct boot_params, the boot loader can load the -32/64-bit kernel in the same way as that of 16-bit boot protocol. - -In 32-bit boot protocol, the kernel is started by jumping to the -32-bit kernel entry point, which is the start address of loaded -32/64-bit kernel. - -At entry, the CPU must be in 32-bit protected mode with paging -disabled; a GDT must be loaded with the descriptors for selectors -__BOOT_CS(0x10) and __BOOT_DS(0x18); both descriptors must be 4G flat -segment; __BOOS_CS must have execute/read permission, and __BOOT_DS -must have read/write permission; CS must be __BOOT_CS and DS, ES, SS -must be __BOOT_DS; interrupt must be disabled; %esi must hold the base -address of the struct boot_params; %ebp, %edi and %ebx must be zero. diff --git a/Documentation/i386/usb-legacy-support.txt b/Documentation/i386/usb-legacy-support.txt deleted file mode 100644 index 1894cdfc69d9..000000000000 --- a/Documentation/i386/usb-legacy-support.txt +++ /dev/null @@ -1,44 +0,0 @@ -USB Legacy support -~~~~~~~~~~~~~~~~~~ - -Vojtech Pavlik , January 2004 - - -Also known as "USB Keyboard" or "USB Mouse support" in the BIOS Setup is a -feature that allows one to use the USB mouse and keyboard as if they were -their classic PS/2 counterparts. This means one can use an USB keyboard to -type in LILO for example. - -It has several drawbacks, though: - -1) On some machines, the emulated PS/2 mouse takes over even when no USB - mouse is present and a real PS/2 mouse is present. In that case the extra - features (wheel, extra buttons, touchpad mode) of the real PS/2 mouse may - not be available. - -2) If CONFIG_HIGHMEM64G is enabled, the PS/2 mouse emulation can cause - system crashes, because the SMM BIOS is not expecting to be in PAE mode. - The Intel E7505 is a typical machine where this happens. - -3) If AMD64 64-bit mode is enabled, again system crashes often happen, - because the SMM BIOS isn't expecting the CPU to be in 64-bit mode. The - BIOS manufacturers only test with Windows, and Windows doesn't do 64-bit - yet. - -Solutions: - -Problem 1) can be solved by loading the USB drivers prior to loading the -PS/2 mouse driver. Since the PS/2 mouse driver is in 2.6 compiled into -the kernel unconditionally, this means the USB drivers need to be -compiled-in, too. - -Problem 2) can currently only be solved by either disabling HIGHMEM64G -in the kernel config or USB Legacy support in the BIOS. A BIOS update -could help, but so far no such update exists. - -Problem 3) is usually fixed by a BIOS update. Check the board -manufacturers web site. If an update is not available, disable USB -Legacy support in the BIOS. If this alone doesn't help, try also adding -idle=poll on the kernel command line. The BIOS may be entering the SMM -on the HLT instruction as well. - diff --git a/Documentation/i386/zero-page.txt b/Documentation/i386/zero-page.txt deleted file mode 100644 index 169ad423a3d1..000000000000 --- a/Documentation/i386/zero-page.txt +++ /dev/null @@ -1,31 +0,0 @@ -The additional fields in struct boot_params as a part of 32-bit boot -protocol of kernel. These should be filled by bootloader or 16-bit -real-mode setup code of the kernel. References/settings to it mainly -are in: - - include/asm-x86/bootparam.h - - -Offset Proto Name Meaning -/Size - -000/040 ALL screen_info Text mode or frame buffer information - (struct screen_info) -040/014 ALL apm_bios_info APM BIOS information (struct apm_bios_info) -060/010 ALL ist_info Intel SpeedStep (IST) BIOS support information - (struct ist_info) -080/010 ALL hd0_info hd0 disk parameter, OBSOLETE!! -090/010 ALL hd1_info hd1 disk parameter, OBSOLETE!! -0A0/010 ALL sys_desc_table System description table (struct sys_desc_table) -140/080 ALL edid_info Video mode setup (struct edid_info) -1C0/020 ALL efi_info EFI 32 information (struct efi_info) -1E0/004 ALL alk_mem_k Alternative mem check, in KB -1E4/004 ALL scratch Scratch field for the kernel setup code -1E8/001 ALL e820_entries Number of entries in e820_map (below) -1E9/001 ALL eddbuf_entries Number of entries in eddbuf (below) -1EA/001 ALL edd_mbr_sig_buf_entries Number of entries in edd_mbr_sig_buffer - (below) -290/040 ALL edd_mbr_sig_buffer EDD MBR signatures -2D0/A00 ALL e820_map E820 memory map table - (array of struct e820entry) -D00/1EC ALL eddbuf EDD data (array of struct edd_info) diff --git a/Documentation/x86/i386/IO-APIC.txt b/Documentation/x86/i386/IO-APIC.txt new file mode 100644 index 000000000000..30b4c714fbe1 --- /dev/null +++ b/Documentation/x86/i386/IO-APIC.txt @@ -0,0 +1,119 @@ +Most (all) Intel-MP compliant SMP boards have the so-called 'IO-APIC', +which is an enhanced interrupt controller. It enables us to route +hardware interrupts to multiple CPUs, or to CPU groups. Without an +IO-APIC, interrupts from hardware will be delivered only to the +CPU which boots the operating system (usually CPU#0). + +Linux supports all variants of compliant SMP boards, including ones with +multiple IO-APICs. Multiple IO-APICs are used in high-end servers to +distribute IRQ load further. + +There are (a few) known breakages in certain older boards, such bugs are +usually worked around by the kernel. If your MP-compliant SMP board does +not boot Linux, then consult the linux-smp mailing list archives first. + +If your box boots fine with enabled IO-APIC IRQs, then your +/proc/interrupts will look like this one: + + ----------------------------> + hell:~> cat /proc/interrupts + CPU0 + 0: 1360293 IO-APIC-edge timer + 1: 4 IO-APIC-edge keyboard + 2: 0 XT-PIC cascade + 13: 1 XT-PIC fpu + 14: 1448 IO-APIC-edge ide0 + 16: 28232 IO-APIC-level Intel EtherExpress Pro 10/100 Ethernet + 17: 51304 IO-APIC-level eth0 + NMI: 0 + ERR: 0 + hell:~> + <---------------------------- + +Some interrupts are still listed as 'XT PIC', but this is not a problem; +none of those IRQ sources is performance-critical. + + +In the unlikely case that your board does not create a working mp-table, +you can use the pirq= boot parameter to 'hand-construct' IRQ entries. This +is non-trivial though and cannot be automated. One sample /etc/lilo.conf +entry: + + append="pirq=15,11,10" + +The actual numbers depend on your system, on your PCI cards and on their +PCI slot position. Usually PCI slots are 'daisy chained' before they are +connected to the PCI chipset IRQ routing facility (the incoming PIRQ1-4 +lines): + + ,-. ,-. ,-. ,-. ,-. + PIRQ4 ----| |-. ,-| |-. ,-| |-. ,-| |--------| | + |S| \ / |S| \ / |S| \ / |S| |S| + PIRQ3 ----|l|-. `/---|l|-. `/---|l|-. `/---|l|--------|l| + |o| \/ |o| \/ |o| \/ |o| |o| + PIRQ2 ----|t|-./`----|t|-./`----|t|-./`----|t|--------|t| + |1| /\ |2| /\ |3| /\ |4| |5| + PIRQ1 ----| |- `----| |- `----| |- `----| |--------| | + `-' `-' `-' `-' `-' + +Every PCI card emits a PCI IRQ, which can be INTA, INTB, INTC or INTD: + + ,-. + INTD--| | + |S| + INTC--|l| + |o| + INTB--|t| + |x| + INTA--| | + `-' + +These INTA-D PCI IRQs are always 'local to the card', their real meaning +depends on which slot they are in. If you look at the daisy chaining diagram, +a card in slot4, issuing INTA IRQ, it will end up as a signal on PIRQ4 of +the PCI chipset. Most cards issue INTA, this creates optimal distribution +between the PIRQ lines. (distributing IRQ sources properly is not a +necessity, PCI IRQs can be shared at will, but it's a good for performance +to have non shared interrupts). Slot5 should be used for videocards, they +do not use interrupts normally, thus they are not daisy chained either. + +so if you have your SCSI card (IRQ11) in Slot1, Tulip card (IRQ9) in +Slot2, then you'll have to specify this pirq= line: + + append="pirq=11,9" + +the following script tries to figure out such a default pirq= line from +your PCI configuration: + + echo -n pirq=; echo `scanpci | grep T_L | cut -c56-` | sed 's/ /,/g' + +note that this script wont work if you have skipped a few slots or if your +board does not do default daisy-chaining. (or the IO-APIC has the PIRQ pins +connected in some strange way). E.g. if in the above case you have your SCSI +card (IRQ11) in Slot3, and have Slot1 empty: + + append="pirq=0,9,11" + +[value '0' is a generic 'placeholder', reserved for empty (or non-IRQ emitting) +slots.] + +Generally, it's always possible to find out the correct pirq= settings, just +permute all IRQ numbers properly ... it will take some time though. An +'incorrect' pirq line will cause the booting process to hang, or a device +won't function properly (e.g. if it's inserted as a module). + +If you have 2 PCI buses, then you can use up to 8 pirq values, although such +boards tend to have a good configuration. + +Be prepared that it might happen that you need some strange pirq line: + + append="pirq=0,0,0,0,0,0,9,11" + +Use smart trial-and-error techniques to find out the correct pirq line ... + +Good luck and mail to linux-smp@vger.kernel.org or +linux-kernel@vger.kernel.org if you have any problems that are not covered +by this document. + +-- mingo + diff --git a/Documentation/x86/i386/boot.txt b/Documentation/x86/i386/boot.txt new file mode 100644 index 000000000000..147bfe511cdd --- /dev/null +++ b/Documentation/x86/i386/boot.txt @@ -0,0 +1,900 @@ + THE LINUX/x86 BOOT PROTOCOL + --------------------------- + +On the x86 platform, the Linux kernel uses a rather complicated boot +convention. This has evolved partially due to historical aspects, as +well as the desire in the early days to have the kernel itself be a +bootable image, the complicated PC memory model and due to changed +expectations in the PC industry caused by the effective demise of +real-mode DOS as a mainstream operating system. + +Currently, the following versions of the Linux/x86 boot protocol exist. + +Old kernels: zImage/Image support only. Some very early kernels + may not even support a command line. + +Protocol 2.00: (Kernel 1.3.73) Added bzImage and initrd support, as + well as a formalized way to communicate between the + boot loader and the kernel. setup.S made relocatable, + although the traditional setup area still assumed + writable. + +Protocol 2.01: (Kernel 1.3.76) Added a heap overrun warning. + +Protocol 2.02: (Kernel 2.4.0-test3-pre3) New command line protocol. + Lower the conventional memory ceiling. No overwrite + of the traditional setup area, thus making booting + safe for systems which use the EBDA from SMM or 32-bit + BIOS entry points. zImage deprecated but still + supported. + +Protocol 2.03: (Kernel 2.4.18-pre1) Explicitly makes the highest possible + initrd address available to the bootloader. + +Protocol 2.04: (Kernel 2.6.14) Extend the syssize field to four bytes. + +Protocol 2.05: (Kernel 2.6.20) Make protected mode kernel relocatable. + Introduce relocatable_kernel and kernel_alignment fields. + +Protocol 2.06: (Kernel 2.6.22) Added a field that contains the size of + the boot command line. + +Protocol 2.07: (Kernel 2.6.24) Added paravirtualised boot protocol. + Introduced hardware_subarch and hardware_subarch_data + and KEEP_SEGMENTS flag in load_flags. + +Protocol 2.08: (Kernel 2.6.26) Added crc32 checksum and ELF format + payload. Introduced payload_offset and payload length + fields to aid in locating the payload. + +Protocol 2.09: (Kernel 2.6.26) Added a field of 64-bit physical + pointer to single linked list of struct setup_data. + +**** MEMORY LAYOUT + +The traditional memory map for the kernel loader, used for Image or +zImage kernels, typically looks like: + + | | +0A0000 +------------------------+ + | Reserved for BIOS | Do not use. Reserved for BIOS EBDA. +09A000 +------------------------+ + | Command line | + | Stack/heap | For use by the kernel real-mode code. +098000 +------------------------+ + | Kernel setup | The kernel real-mode code. +090200 +------------------------+ + | Kernel boot sector | The kernel legacy boot sector. +090000 +------------------------+ + | Protected-mode kernel | The bulk of the kernel image. +010000 +------------------------+ + | Boot loader | <- Boot sector entry point 0000:7C00 +001000 +------------------------+ + | Reserved for MBR/BIOS | +000800 +------------------------+ + | Typically used by MBR | +000600 +------------------------+ + | BIOS use only | +000000 +------------------------+ + + +When using bzImage, the protected-mode kernel was relocated to +0x100000 ("high memory"), and the kernel real-mode block (boot sector, +setup, and stack/heap) was made relocatable to any address between +0x10000 and end of low memory. Unfortunately, in protocols 2.00 and +2.01 the 0x90000+ memory range is still used internally by the kernel; +the 2.02 protocol resolves that problem. + +It is desirable to keep the "memory ceiling" -- the highest point in +low memory touched by the boot loader -- as low as possible, since +some newer BIOSes have begun to allocate some rather large amounts of +memory, called the Extended BIOS Data Area, near the top of low +memory. The boot loader should use the "INT 12h" BIOS call to verify +how much low memory is available. + +Unfortunately, if INT 12h reports that the amount of memory is too +low, there is usually nothing the boot loader can do but to report an +error to the user. The boot loader should therefore be designed to +take up as little space in low memory as it reasonably can. For +zImage or old bzImage kernels, which need data written into the +0x90000 segment, the boot loader should make sure not to use memory +above the 0x9A000 point; too many BIOSes will break above that point. + +For a modern bzImage kernel with boot protocol version >= 2.02, a +memory layout like the following is suggested: + + ~ ~ + | Protected-mode kernel | +100000 +------------------------+ + | I/O memory hole | +0A0000 +------------------------+ + | Reserved for BIOS | Leave as much as possible unused + ~ ~ + | Command line | (Can also be below the X+10000 mark) +X+10000 +------------------------+ + | Stack/heap | For use by the kernel real-mode code. +X+08000 +------------------------+ + | Kernel setup | The kernel real-mode code. + | Kernel boot sector | The kernel legacy boot sector. +X +------------------------+ + | Boot loader | <- Boot sector entry point 0000:7C00 +001000 +------------------------+ + | Reserved for MBR/BIOS | +000800 +------------------------+ + | Typically used by MBR | +000600 +------------------------+ + | BIOS use only | +000000 +------------------------+ + +... where the address X is as low as the design of the boot loader +permits. + + +**** THE REAL-MODE KERNEL HEADER + +In the following text, and anywhere in the kernel boot sequence, "a +sector" refers to 512 bytes. It is independent of the actual sector +size of the underlying medium. + +The first step in loading a Linux kernel should be to load the +real-mode code (boot sector and setup code) and then examine the +following header at offset 0x01f1. The real-mode code can total up to +32K, although the boot loader may choose to load only the first two +sectors (1K) and then examine the bootup sector size. + +The header looks like: + +Offset Proto Name Meaning +/Size + +01F1/1 ALL(1 setup_sects The size of the setup in sectors +01F2/2 ALL root_flags If set, the root is mounted readonly +01F4/4 2.04+(2 syssize The size of the 32-bit code in 16-byte paras +01F8/2 ALL ram_size DO NOT USE - for bootsect.S use only +01FA/2 ALL vid_mode Video mode control +01FC/2 ALL root_dev Default root device number +01FE/2 ALL boot_flag 0xAA55 magic number +0200/2 2.00+ jump Jump instruction +0202/4 2.00+ header Magic signature "HdrS" +0206/2 2.00+ version Boot protocol version supported +0208/4 2.00+ realmode_swtch Boot loader hook (see below) +020C/2 2.00+ start_sys The load-low segment (0x1000) (obsolete) +020E/2 2.00+ kernel_version Pointer to kernel version string +0210/1 2.00+ type_of_loader Boot loader identifier +0211/1 2.00+ loadflags Boot protocol option flags +0212/2 2.00+ setup_move_size Move to high memory size (used with hooks) +0214/4 2.00+ code32_start Boot loader hook (see below) +0218/4 2.00+ ramdisk_image initrd load address (set by boot loader) +021C/4 2.00+ ramdisk_size initrd size (set by boot loader) +0220/4 2.00+ bootsect_kludge DO NOT USE - for bootsect.S use only +0224/2 2.01+ heap_end_ptr Free memory after setup end +0226/2 N/A pad1 Unused +0228/4 2.02+ cmd_line_ptr 32-bit pointer to the kernel command line +022C/4 2.03+ initrd_addr_max Highest legal initrd address +0230/4 2.05+ kernel_alignment Physical addr alignment required for kernel +0234/1 2.05+ relocatable_kernel Whether kernel is relocatable or not +0235/3 N/A pad2 Unused +0238/4 2.06+ cmdline_size Maximum size of the kernel command line +023C/4 2.07+ hardware_subarch Hardware subarchitecture +0240/8 2.07+ hardware_subarch_data Subarchitecture-specific data +0248/4 2.08+ payload_offset Offset of kernel payload +024C/4 2.08+ payload_length Length of kernel payload +0250/8 2.09+ setup_data 64-bit physical pointer to linked list + of struct setup_data + +(1) For backwards compatibility, if the setup_sects field contains 0, the + real value is 4. + +(2) For boot protocol prior to 2.04, the upper two bytes of the syssize + field are unusable, which means the size of a bzImage kernel + cannot be determined. + +If the "HdrS" (0x53726448) magic number is not found at offset 0x202, +the boot protocol version is "old". Loading an old kernel, the +following parameters should be assumed: + + Image type = zImage + initrd not supported + Real-mode kernel must be located at 0x90000. + +Otherwise, the "version" field contains the protocol version, +e.g. protocol version 2.01 will contain 0x0201 in this field. When +setting fields in the header, you must make sure only to set fields +supported by the protocol version in use. + + +**** DETAILS OF HEADER FIELDS + +For each field, some are information from the kernel to the bootloader +("read"), some are expected to be filled out by the bootloader +("write"), and some are expected to be read and modified by the +bootloader ("modify"). + +All general purpose boot loaders should write the fields marked +(obligatory). Boot loaders who want to load the kernel at a +nonstandard address should fill in the fields marked (reloc); other +boot loaders can ignore those fields. + +The byte order of all fields is littleendian (this is x86, after all.) + +Field name: setup_sects +Type: read +Offset/size: 0x1f1/1 +Protocol: ALL + + The size of the setup code in 512-byte sectors. If this field is + 0, the real value is 4. The real-mode code consists of the boot + sector (always one 512-byte sector) plus the setup code. + +Field name: root_flags +Type: modify (optional) +Offset/size: 0x1f2/2 +Protocol: ALL + + If this field is nonzero, the root defaults to readonly. The use of + this field is deprecated; use the "ro" or "rw" options on the + command line instead. + +Field name: syssize +Type: read +Offset/size: 0x1f4/4 (protocol 2.04+) 0x1f4/2 (protocol ALL) +Protocol: 2.04+ + + The size of the protected-mode code in units of 16-byte paragraphs. + For protocol versions older than 2.04 this field is only two bytes + wide, and therefore cannot be trusted for the size of a kernel if + the LOAD_HIGH flag is set. + +Field name: ram_size +Type: kernel internal +Offset/size: 0x1f8/2 +Protocol: ALL + + This field is obsolete. + +Field name: vid_mode +Type: modify (obligatory) +Offset/size: 0x1fa/2 + + Please see the section on SPECIAL COMMAND LINE OPTIONS. + +Field name: root_dev +Type: modify (optional) +Offset/size: 0x1fc/2 +Protocol: ALL + + The default root device device number. The use of this field is + deprecated, use the "root=" option on the command line instead. + +Field name: boot_flag +Type: read +Offset/size: 0x1fe/2 +Protocol: ALL + + Contains 0xAA55. This is the closest thing old Linux kernels have + to a magic number. + +Field name: jump +Type: read +Offset/size: 0x200/2 +Protocol: 2.00+ + + Contains an x86 jump instruction, 0xEB followed by a signed offset + relative to byte 0x202. This can be used to determine the size of + the header. + +Field name: header +Type: read +Offset/size: 0x202/4 +Protocol: 2.00+ + + Contains the magic number "HdrS" (0x53726448). + +Field name: version +Type: read +Offset/size: 0x206/2 +Protocol: 2.00+ + + Contains the boot protocol version, in (major << 8)+minor format, + e.g. 0x0204 for version 2.04, and 0x0a11 for a hypothetical version + 10.17. + +Field name: readmode_swtch +Type: modify (optional) +Offset/size: 0x208/4 +Protocol: 2.00+ + + Boot loader hook (see ADVANCED BOOT LOADER HOOKS below.) + +Field name: start_sys +Type: read +Offset/size: 0x20c/4 +Protocol: 2.00+ + + The load low segment (0x1000). Obsolete. + +Field name: kernel_version +Type: read +Offset/size: 0x20e/2 +Protocol: 2.00+ + + If set to a nonzero value, contains a pointer to a NUL-terminated + human-readable kernel version number string, less 0x200. This can + be used to display the kernel version to the user. This value + should be less than (0x200*setup_sects). + + For example, if this value is set to 0x1c00, the kernel version + number string can be found at offset 0x1e00 in the kernel file. + This is a valid value if and only if the "setup_sects" field + contains the value 15 or higher, as: + + 0x1c00 < 15*0x200 (= 0x1e00) but + 0x1c00 >= 14*0x200 (= 0x1c00) + + 0x1c00 >> 9 = 14, so the minimum value for setup_secs is 15. + +Field name: type_of_loader +Type: write (obligatory) +Offset/size: 0x210/1 +Protocol: 2.00+ + + If your boot loader has an assigned id (see table below), enter + 0xTV here, where T is an identifier for the boot loader and V is + a version number. Otherwise, enter 0xFF here. + + Assigned boot loader ids: + 0 LILO (0x00 reserved for pre-2.00 bootloader) + 1 Loadlin + 2 bootsect-loader (0x20, all other values reserved) + 3 SYSLINUX + 4 EtherBoot + 5 ELILO + 7 GRuB + 8 U-BOOT + 9 Xen + A Gujin + B Qemu + + Please contact if you need a bootloader ID + value assigned. + +Field name: loadflags +Type: modify (obligatory) +Offset/size: 0x211/1 +Protocol: 2.00+ + + This field is a bitmask. + + Bit 0 (read): LOADED_HIGH + - If 0, the protected-mode code is loaded at 0x10000. + - If 1, the protected-mode code is loaded at 0x100000. + + Bit 5 (write): QUIET_FLAG + - If 0, print early messages. + - If 1, suppress early messages. + This requests to the kernel (decompressor and early + kernel) to not write early messages that require + accessing the display hardware directly. + + Bit 6 (write): KEEP_SEGMENTS + Protocol: 2.07+ + - If 0, reload the segment registers in the 32bit entry point. + - If 1, do not reload the segment registers in the 32bit entry point. + Assume that %cs %ds %ss %es are all set to flat segments with + a base of 0 (or the equivalent for their environment). + + Bit 7 (write): CAN_USE_HEAP + Set this bit to 1 to indicate that the value entered in the + heap_end_ptr is valid. If this field is clear, some setup code + functionality will be disabled. + +Field name: setup_move_size +Type: modify (obligatory) +Offset/size: 0x212/2 +Protocol: 2.00-2.01 + + When using protocol 2.00 or 2.01, if the real mode kernel is not + loaded at 0x90000, it gets moved there later in the loading + sequence. Fill in this field if you want additional data (such as + the kernel command line) moved in addition to the real-mode kernel + itself. + + The unit is bytes starting with the beginning of the boot sector. + + This field is can be ignored when the protocol is 2.02 or higher, or + if the real-mode code is loaded at 0x90000. + +Field name: code32_start +Type: modify (optional, reloc) +Offset/size: 0x214/4 +Protocol: 2.00+ + + The address to jump to in protected mode. This defaults to the load + address of the kernel, and can be used by the boot loader to + determine the proper load address. + + This field can be modified for two purposes: + + 1. as a boot loader hook (see ADVANCED BOOT LOADER HOOKS below.) + + 2. if a bootloader which does not install a hook loads a + relocatable kernel at a nonstandard address it will have to modify + this field to point to the load address. + +Field name: ramdisk_image +Type: write (obligatory) +Offset/size: 0x218/4 +Protocol: 2.00+ + + The 32-bit linear address of the initial ramdisk or ramfs. Leave at + zero if there is no initial ramdisk/ramfs. + +Field name: ramdisk_size +Type: write (obligatory) +Offset/size: 0x21c/4 +Protocol: 2.00+ + + Size of the initial ramdisk or ramfs. Leave at zero if there is no + initial ramdisk/ramfs. + +Field name: bootsect_kludge +Type: kernel internal +Offset/size: 0x220/4 +Protocol: 2.00+ + + This field is obsolete. + +Field name: heap_end_ptr +Type: write (obligatory) +Offset/size: 0x224/2 +Protocol: 2.01+ + + Set this field to the offset (from the beginning of the real-mode + code) of the end of the setup stack/heap, minus 0x0200. + +Field name: cmd_line_ptr +Type: write (obligatory) +Offset/size: 0x228/4 +Protocol: 2.02+ + + Set this field to the linear address of the kernel command line. + The kernel command line can be located anywhere between the end of + the setup heap and 0xA0000; it does not have to be located in the + same 64K segment as the real-mode code itself. + + Fill in this field even if your boot loader does not support a + command line, in which case you can point this to an empty string + (or better yet, to the string "auto".) If this field is left at + zero, the kernel will assume that your boot loader does not support + the 2.02+ protocol. + +Field name: initrd_addr_max +Type: read +Offset/size: 0x22c/4 +Protocol: 2.03+ + + The maximum address that may be occupied by the initial + ramdisk/ramfs contents. For boot protocols 2.02 or earlier, this + field is not present, and the maximum address is 0x37FFFFFF. (This + address is defined as the address of the highest safe byte, so if + your ramdisk is exactly 131072 bytes long and this field is + 0x37FFFFFF, you can start your ramdisk at 0x37FE0000.) + +Field name: kernel_alignment +Type: read (reloc) +Offset/size: 0x230/4 +Protocol: 2.05+ + + Alignment unit required by the kernel (if relocatable_kernel is true.) + +Field name: relocatable_kernel +Type: read (reloc) +Offset/size: 0x234/1 +Protocol: 2.05+ + + If this field is nonzero, the protected-mode part of the kernel can + be loaded at any address that satisfies the kernel_alignment field. + After loading, the boot loader must set the code32_start field to + point to the loaded code, or to a boot loader hook. + +Field name: cmdline_size +Type: read +Offset/size: 0x238/4 +Protocol: 2.06+ + + The maximum size of the command line without the terminating + zero. This means that the command line can contain at most + cmdline_size characters. With protocol version 2.05 and earlier, the + maximum size was 255. + +Field name: hardware_subarch +Type: write (optional, defaults to x86/PC) +Offset/size: 0x23c/4 +Protocol: 2.07+ + + In a paravirtualized environment the hardware low level architectural + pieces such as interrupt handling, page table handling, and + accessing process control registers needs to be done differently. + + This field allows the bootloader to inform the kernel we are in one + one of those environments. + + 0x00000000 The default x86/PC environment + 0x00000001 lguest + 0x00000002 Xen + +Field name: hardware_subarch_data +Type: write (subarch-dependent) +Offset/size: 0x240/8 +Protocol: 2.07+ + + A pointer to data that is specific to hardware subarch + This field is currently unused for the default x86/PC environment, + do not modify. + +Field name: payload_offset +Type: read +Offset/size: 0x248/4 +Protocol: 2.08+ + + If non-zero then this field contains the offset from the end of the + real-mode code to the payload. + + The payload may be compressed. The format of both the compressed and + uncompressed data should be determined using the standard magic + numbers. Currently only gzip compressed ELF is used. + +Field name: payload_length +Type: read +Offset/size: 0x24c/4 +Protocol: 2.08+ + + The length of the payload. + +Field name: setup_data +Type: write (special) +Offset/size: 0x250/8 +Protocol: 2.09+ + + The 64-bit physical pointer to NULL terminated single linked list of + struct setup_data. This is used to define a more extensible boot + parameters passing mechanism. The definition of struct setup_data is + as follow: + + struct setup_data { + u64 next; + u32 type; + u32 len; + u8 data[0]; + }; + + Where, the next is a 64-bit physical pointer to the next node of + linked list, the next field of the last node is 0; the type is used + to identify the contents of data; the len is the length of data + field; the data holds the real payload. + + This list may be modified at a number of points during the bootup + process. Therefore, when modifying this list one should always make + sure to consider the case where the linked list already contains + entries. + + +**** THE IMAGE CHECKSUM + +From boot protocol version 2.08 onwards the CRC-32 is calculated over +the entire file using the characteristic polynomial 0x04C11DB7 and an +initial remainder of 0xffffffff. The checksum is appended to the +file; therefore the CRC of the file up to the limit specified in the +syssize field of the header is always 0. + + +**** THE KERNEL COMMAND LINE + +The kernel command line has become an important way for the boot +loader to communicate with the kernel. Some of its options are also +relevant to the boot loader itself, see "special command line options" +below. + +The kernel command line is a null-terminated string. The maximum +length can be retrieved from the field cmdline_size. Before protocol +version 2.06, the maximum was 255 characters. A string that is too +long will be automatically truncated by the kernel. + +If the boot protocol version is 2.02 or later, the address of the +kernel command line is given by the header field cmd_line_ptr (see +above.) This address can be anywhere between the end of the setup +heap and 0xA0000. + +If the protocol version is *not* 2.02 or higher, the kernel +command line is entered using the following protocol: + + At offset 0x0020 (word), "cmd_line_magic", enter the magic + number 0xA33F. + + At offset 0x0022 (word), "cmd_line_offset", enter the offset + of the kernel command line (relative to the start of the + real-mode kernel). + + The kernel command line *must* be within the memory region + covered by setup_move_size, so you may need to adjust this + field. + + +**** MEMORY LAYOUT OF THE REAL-MODE CODE + +The real-mode code requires a stack/heap to be set up, as well as +memory allocated for the kernel command line. This needs to be done +in the real-mode accessible memory in bottom megabyte. + +It should be noted that modern machines often have a sizable Extended +BIOS Data Area (EBDA). As a result, it is advisable to use as little +of the low megabyte as possible. + +Unfortunately, under the following circumstances the 0x90000 memory +segment has to be used: + + - When loading a zImage kernel ((loadflags & 0x01) == 0). + - When loading a 2.01 or earlier boot protocol kernel. + + -> For the 2.00 and 2.01 boot protocols, the real-mode code + can be loaded at another address, but it is internally + relocated to 0x90000. For the "old" protocol, the + real-mode code must be loaded at 0x90000. + +When loading at 0x90000, avoid using memory above 0x9a000. + +For boot protocol 2.02 or higher, the command line does not have to be +located in the same 64K segment as the real-mode setup code; it is +thus permitted to give the stack/heap the full 64K segment and locate +the command line above it. + +The kernel command line should not be located below the real-mode +code, nor should it be located in high memory. + + +**** SAMPLE BOOT CONFIGURATION + +As a sample configuration, assume the following layout of the real +mode segment: + + When loading below 0x90000, use the entire segment: + + 0x0000-0x7fff Real mode kernel + 0x8000-0xdfff Stack and heap + 0xe000-0xffff Kernel command line + + When loading at 0x90000 OR the protocol version is 2.01 or earlier: + + 0x0000-0x7fff Real mode kernel + 0x8000-0x97ff Stack and heap + 0x9800-0x9fff Kernel command line + +Such a boot loader should enter the following fields in the header: + + unsigned long base_ptr; /* base address for real-mode segment */ + + if ( setup_sects == 0 ) { + setup_sects = 4; + } + + if ( protocol >= 0x0200 ) { + type_of_loader = ; + if ( loading_initrd ) { + ramdisk_image = ; + ramdisk_size = ; + } + + if ( protocol >= 0x0202 && loadflags & 0x01 ) + heap_end = 0xe000; + else + heap_end = 0x9800; + + if ( protocol >= 0x0201 ) { + heap_end_ptr = heap_end - 0x200; + loadflags |= 0x80; /* CAN_USE_HEAP */ + } + + if ( protocol >= 0x0202 ) { + cmd_line_ptr = base_ptr + heap_end; + strcpy(cmd_line_ptr, cmdline); + } else { + cmd_line_magic = 0xA33F; + cmd_line_offset = heap_end; + setup_move_size = heap_end + strlen(cmdline)+1; + strcpy(base_ptr+cmd_line_offset, cmdline); + } + } else { + /* Very old kernel */ + + heap_end = 0x9800; + + cmd_line_magic = 0xA33F; + cmd_line_offset = heap_end; + + /* A very old kernel MUST have its real-mode code + loaded at 0x90000 */ + + if ( base_ptr != 0x90000 ) { + /* Copy the real-mode kernel */ + memcpy(0x90000, base_ptr, (setup_sects+1)*512); + base_ptr = 0x90000; /* Relocated */ + } + + strcpy(0x90000+cmd_line_offset, cmdline); + + /* It is recommended to clear memory up to the 32K mark */ + memset(0x90000 + (setup_sects+1)*512, 0, + (64-(setup_sects+1))*512); + } + + +**** LOADING THE REST OF THE KERNEL + +The 32-bit (non-real-mode) kernel starts at offset (setup_sects+1)*512 +in the kernel file (again, if setup_sects == 0 the real value is 4.) +It should be loaded at address 0x10000 for Image/zImage kernels and +0x100000 for bzImage kernels. + +The kernel is a bzImage kernel if the protocol >= 2.00 and the 0x01 +bit (LOAD_HIGH) in the loadflags field is set: + + is_bzImage = (protocol >= 0x0200) && (loadflags & 0x01); + load_address = is_bzImage ? 0x100000 : 0x10000; + +Note that Image/zImage kernels can be up to 512K in size, and thus use +the entire 0x10000-0x90000 range of memory. This means it is pretty +much a requirement for these kernels to load the real-mode part at +0x90000. bzImage kernels allow much more flexibility. + + +**** SPECIAL COMMAND LINE OPTIONS + +If the command line provided by the boot loader is entered by the +user, the user may expect the following command line options to work. +They should normally not be deleted from the kernel command line even +though not all of them are actually meaningful to the kernel. Boot +loader authors who need additional command line options for the boot +loader itself should get them registered in +Documentation/kernel-parameters.txt to make sure they will not +conflict with actual kernel options now or in the future. + + vga= + here is either an integer (in C notation, either + decimal, octal, or hexadecimal) or one of the strings + "normal" (meaning 0xFFFF), "ext" (meaning 0xFFFE) or "ask" + (meaning 0xFFFD). This value should be entered into the + vid_mode field, as it is used by the kernel before the command + line is parsed. + + mem= + is an integer in C notation optionally followed by + (case insensitive) K, M, G, T, P or E (meaning << 10, << 20, + << 30, << 40, << 50 or << 60). This specifies the end of + memory to the kernel. This affects the possible placement of + an initrd, since an initrd should be placed near end of + memory. Note that this is an option to *both* the kernel and + the bootloader! + + initrd= + An initrd should be loaded. The meaning of is + obviously bootloader-dependent, and some boot loaders + (e.g. LILO) do not have such a command. + +In addition, some boot loaders add the following options to the +user-specified command line: + + BOOT_IMAGE= + The boot image which was loaded. Again, the meaning of + is obviously bootloader-dependent. + + auto + The kernel was booted without explicit user intervention. + +If these options are added by the boot loader, it is highly +recommended that they are located *first*, before the user-specified +or configuration-specified command line. Otherwise, "init=/bin/sh" +gets confused by the "auto" option. + + +**** RUNNING THE KERNEL + +The kernel is started by jumping to the kernel entry point, which is +located at *segment* offset 0x20 from the start of the real mode +kernel. This means that if you loaded your real-mode kernel code at +0x90000, the kernel entry point is 9020:0000. + +At entry, ds = es = ss should point to the start of the real-mode +kernel code (0x9000 if the code is loaded at 0x90000), sp should be +set up properly, normally pointing to the top of the heap, and +interrupts should be disabled. Furthermore, to guard against bugs in +the kernel, it is recommended that the boot loader sets fs = gs = ds = +es = ss. + +In our example from above, we would do: + + /* Note: in the case of the "old" kernel protocol, base_ptr must + be == 0x90000 at this point; see the previous sample code */ + + seg = base_ptr >> 4; + + cli(); /* Enter with interrupts disabled! */ + + /* Set up the real-mode kernel stack */ + _SS = seg; + _SP = heap_end; + + _DS = _ES = _FS = _GS = seg; + jmp_far(seg+0x20, 0); /* Run the kernel */ + +If your boot sector accesses a floppy drive, it is recommended to +switch off the floppy motor before running the kernel, since the +kernel boot leaves interrupts off and thus the motor will not be +switched off, especially if the loaded kernel has the floppy driver as +a demand-loaded module! + + +**** ADVANCED BOOT LOADER HOOKS + +If the boot loader runs in a particularly hostile environment (such as +LOADLIN, which runs under DOS) it may be impossible to follow the +standard memory location requirements. Such a boot loader may use the +following hooks that, if set, are invoked by the kernel at the +appropriate time. The use of these hooks should probably be +considered an absolutely last resort! + +IMPORTANT: All the hooks are required to preserve %esp, %ebp, %esi and +%edi across invocation. + + realmode_swtch: + A 16-bit real mode far subroutine invoked immediately before + entering protected mode. The default routine disables NMI, so + your routine should probably do so, too. + + code32_start: + A 32-bit flat-mode routine *jumped* to immediately after the + transition to protected mode, but before the kernel is + uncompressed. No segments, except CS, are guaranteed to be + set up (current kernels do, but older ones do not); you should + set them up to BOOT_DS (0x18) yourself. + + After completing your hook, you should jump to the address + that was in this field before your boot loader overwrote it + (relocated, if appropriate.) + + +**** 32-bit BOOT PROTOCOL + +For machine with some new BIOS other than legacy BIOS, such as EFI, +LinuxBIOS, etc, and kexec, the 16-bit real mode setup code in kernel +based on legacy BIOS can not be used, so a 32-bit boot protocol needs +to be defined. + +In 32-bit boot protocol, the first step in loading a Linux kernel +should be to setup the boot parameters (struct boot_params, +traditionally known as "zero page"). The memory for struct boot_params +should be allocated and initialized to all zero. Then the setup header +from offset 0x01f1 of kernel image on should be loaded into struct +boot_params and examined. The end of setup header can be calculated as +follow: + + 0x0202 + byte value at offset 0x0201 + +In addition to read/modify/write the setup header of the struct +boot_params as that of 16-bit boot protocol, the boot loader should +also fill the additional fields of the struct boot_params as that +described in zero-page.txt. + +After setupping the struct boot_params, the boot loader can load the +32/64-bit kernel in the same way as that of 16-bit boot protocol. + +In 32-bit boot protocol, the kernel is started by jumping to the +32-bit kernel entry point, which is the start address of loaded +32/64-bit kernel. + +At entry, the CPU must be in 32-bit protected mode with paging +disabled; a GDT must be loaded with the descriptors for selectors +__BOOT_CS(0x10) and __BOOT_DS(0x18); both descriptors must be 4G flat +segment; __BOOS_CS must have execute/read permission, and __BOOT_DS +must have read/write permission; CS must be __BOOT_CS and DS, ES, SS +must be __BOOT_DS; interrupt must be disabled; %esi must hold the base +address of the struct boot_params; %ebp, %edi and %ebx must be zero. diff --git a/Documentation/x86/i386/usb-legacy-support.txt b/Documentation/x86/i386/usb-legacy-support.txt new file mode 100644 index 000000000000..1894cdfc69d9 --- /dev/null +++ b/Documentation/x86/i386/usb-legacy-support.txt @@ -0,0 +1,44 @@ +USB Legacy support +~~~~~~~~~~~~~~~~~~ + +Vojtech Pavlik , January 2004 + + +Also known as "USB Keyboard" or "USB Mouse support" in the BIOS Setup is a +feature that allows one to use the USB mouse and keyboard as if they were +their classic PS/2 counterparts. This means one can use an USB keyboard to +type in LILO for example. + +It has several drawbacks, though: + +1) On some machines, the emulated PS/2 mouse takes over even when no USB + mouse is present and a real PS/2 mouse is present. In that case the extra + features (wheel, extra buttons, touchpad mode) of the real PS/2 mouse may + not be available. + +2) If CONFIG_HIGHMEM64G is enabled, the PS/2 mouse emulation can cause + system crashes, because the SMM BIOS is not expecting to be in PAE mode. + The Intel E7505 is a typical machine where this happens. + +3) If AMD64 64-bit mode is enabled, again system crashes often happen, + because the SMM BIOS isn't expecting the CPU to be in 64-bit mode. The + BIOS manufacturers only test with Windows, and Windows doesn't do 64-bit + yet. + +Solutions: + +Problem 1) can be solved by loading the USB drivers prior to loading the +PS/2 mouse driver. Since the PS/2 mouse driver is in 2.6 compiled into +the kernel unconditionally, this means the USB drivers need to be +compiled-in, too. + +Problem 2) can currently only be solved by either disabling HIGHMEM64G +in the kernel config or USB Legacy support in the BIOS. A BIOS update +could help, but so far no such update exists. + +Problem 3) is usually fixed by a BIOS update. Check the board +manufacturers web site. If an update is not available, disable USB +Legacy support in the BIOS. If this alone doesn't help, try also adding +idle=poll on the kernel command line. The BIOS may be entering the SMM +on the HLT instruction as well. + diff --git a/Documentation/x86/i386/zero-page.txt b/Documentation/x86/i386/zero-page.txt new file mode 100644 index 000000000000..169ad423a3d1 --- /dev/null +++ b/Documentation/x86/i386/zero-page.txt @@ -0,0 +1,31 @@ +The additional fields in struct boot_params as a part of 32-bit boot +protocol of kernel. These should be filled by bootloader or 16-bit +real-mode setup code of the kernel. References/settings to it mainly +are in: + + include/asm-x86/bootparam.h + + +Offset Proto Name Meaning +/Size + +000/040 ALL screen_info Text mode or frame buffer information + (struct screen_info) +040/014 ALL apm_bios_info APM BIOS information (struct apm_bios_info) +060/010 ALL ist_info Intel SpeedStep (IST) BIOS support information + (struct ist_info) +080/010 ALL hd0_info hd0 disk parameter, OBSOLETE!! +090/010 ALL hd1_info hd1 disk parameter, OBSOLETE!! +0A0/010 ALL sys_desc_table System description table (struct sys_desc_table) +140/080 ALL edid_info Video mode setup (struct edid_info) +1C0/020 ALL efi_info EFI 32 information (struct efi_info) +1E0/004 ALL alk_mem_k Alternative mem check, in KB +1E4/004 ALL scratch Scratch field for the kernel setup code +1E8/001 ALL e820_entries Number of entries in e820_map (below) +1E9/001 ALL eddbuf_entries Number of entries in eddbuf (below) +1EA/001 ALL edd_mbr_sig_buf_entries Number of entries in edd_mbr_sig_buffer + (below) +290/040 ALL edd_mbr_sig_buffer EDD MBR signatures +2D0/A00 ALL e820_map E820 memory map table + (array of struct e820entry) +D00/1EC ALL eddbuf EDD data (array of struct edd_info) diff --git a/Documentation/x86/x86_64/00-INDEX b/Documentation/x86/x86_64/00-INDEX new file mode 100644 index 000000000000..92fc20ab5f0e --- /dev/null +++ b/Documentation/x86/x86_64/00-INDEX @@ -0,0 +1,16 @@ +00-INDEX + - This file +boot-options.txt + - AMD64-specific boot options. +cpu-hotplug-spec + - Firmware support for CPU hotplug under Linux/x86-64 +fake-numa-for-cpusets + - Using numa=fake and CPUSets for Resource Management +kernel-stacks + - Context-specific per-processor interrupt stacks. +machinecheck + - Configurable sysfs parameters for the x86-64 machine check code. +mm.txt + - Memory layout of x86-64 (4 level page tables, 46 bits physical). +uefi.txt + - Booting Linux via Unified Extensible Firmware Interface. diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt new file mode 100644 index 000000000000..b0c7b6c4abda --- /dev/null +++ b/Documentation/x86/x86_64/boot-options.txt @@ -0,0 +1,314 @@ +AMD64 specific boot options + +There are many others (usually documented in driver documentation), but +only the AMD64 specific ones are listed here. + +Machine check + + mce=off disable machine check + mce=bootlog Enable logging of machine checks left over from booting. + Disabled by default on AMD because some BIOS leave bogus ones. + If your BIOS doesn't do that it's a good idea to enable though + to make sure you log even machine check events that result + in a reboot. On Intel systems it is enabled by default. + mce=nobootlog + Disable boot machine check logging. + mce=tolerancelevel (number) + 0: always panic on uncorrected errors, log corrected errors + 1: panic or SIGBUS on uncorrected errors, log corrected errors + 2: SIGBUS or log uncorrected errors, log corrected errors + 3: never panic or SIGBUS, log all errors (for testing only) + Default is 1 + Can be also set using sysfs which is preferable. + + nomce (for compatibility with i386): same as mce=off + + Everything else is in sysfs now. + +APICs + + apic Use IO-APIC. Default + + noapic Don't use the IO-APIC. + + disableapic Don't use the local APIC + + nolapic Don't use the local APIC (alias for i386 compatibility) + + pirq=... See Documentation/i386/IO-APIC.txt + + noapictimer Don't set up the APIC timer + + no_timer_check Don't check the IO-APIC timer. This can work around + problems with incorrect timer initialization on some boards. + + apicmaintimer Run time keeping from the local APIC timer instead + of using the PIT/HPET interrupt for this. This is useful + when the PIT/HPET interrupts are unreliable. + + noapicmaintimer Don't do time keeping using the APIC timer. + Useful when this option was auto selected, but doesn't work. + + apicpmtimer + Do APIC timer calibration using the pmtimer. Implies + apicmaintimer. Useful when your PIT timer is totally + broken. + + disable_8254_timer / enable_8254_timer + Enable interrupt 0 timer routing over the 8254 in addition to over + the IO-APIC. The kernel tries to set a sensible default. + +Early Console + + syntax: earlyprintk=vga + earlyprintk=serial[,ttySn[,baudrate]] + + The early console is useful when the kernel crashes before the + normal console is initialized. It is not enabled by + default because it has some cosmetic problems. + Append ,keep to not disable it when the real console takes over. + Only vga or serial at a time, not both. + Currently only ttyS0 and ttyS1 are supported. + Interaction with the standard serial driver is not very good. + The VGA output is eventually overwritten by the real console. + +Timing + + notsc + Don't use the CPU time stamp counter to read the wall time. + This can be used to work around timing problems on multiprocessor systems + with not properly synchronized CPUs. + + report_lost_ticks + Report when timer interrupts are lost because some code turned off + interrupts for too long. + + nmi_watchdog=NUMBER[,panic] + NUMBER can be: + 0 don't use an NMI watchdog + 1 use the IO-APIC timer for the NMI watchdog + 2 use the local APIC for the NMI watchdog using a performance counter. Note + This will use one performance counter and the local APIC's performance + vector. + When panic is specified panic when an NMI watchdog timeout occurs. + This is useful when you use a panic=... timeout and need the box + quickly up again. + + nohpet + Don't use the HPET timer. + +Idle loop + + idle=poll + Don't do power saving in the idle loop using HLT, but poll for rescheduling + event. This will make the CPUs eat a lot more power, but may be useful + to get slightly better performance in multiprocessor benchmarks. It also + makes some profiling using performance counters more accurate. + Please note that on systems with MONITOR/MWAIT support (like Intel EM64T + CPUs) this option has no performance advantage over the normal idle loop. + It may also interact badly with hyperthreading. + +Rebooting + + reboot=b[ios] | t[riple] | k[bd] | a[cpi] | e[fi] [, [w]arm | [c]old] + bios Use the CPU reboot vector for warm reset + warm Don't set the cold reboot flag + cold Set the cold reboot flag + triple Force a triple fault (init) + kbd Use the keyboard controller. cold reset (default) + acpi Use the ACPI RESET_REG in the FADT. If ACPI is not configured or the + ACPI reset does not work, the reboot path attempts the reset using + the keyboard controller. + efi Use efi reset_system runtime service. If EFI is not configured or the + EFI reset does not work, the reboot path attempts the reset using + the keyboard controller. + + Using warm reset will be much faster especially on big memory + systems because the BIOS will not go through the memory check. + Disadvantage is that not all hardware will be completely reinitialized + on reboot so there may be boot problems on some systems. + + reboot=force + + Don't stop other CPUs on reboot. This can make reboot more reliable + in some cases. + +Non Executable Mappings + + noexec=on|off + + on Enable(default) + off Disable + +SMP + + additional_cpus=NUM Allow NUM more CPUs for hotplug + (defaults are specified by the BIOS, see Documentation/x86_64/cpu-hotplug-spec) + +NUMA + + numa=off Only set up a single NUMA node spanning all memory. + + numa=noacpi Don't parse the SRAT table for NUMA setup + + numa=fake=CMDLINE + If a number, fakes CMDLINE nodes and ignores NUMA setup of the + actual machine. Otherwise, system memory is configured + depending on the sizes and coefficients listed. For example: + numa=fake=2*512,1024,4*256,*128 + gives two 512M nodes, a 1024M node, four 256M nodes, and the + rest split into 128M chunks. If the last character of CMDLINE + is a *, the remaining memory is divided up equally among its + coefficient: + numa=fake=2*512,2* + gives two 512M nodes and the rest split into two nodes. + Otherwise, the remaining system RAM is allocated to an + additional node. + + numa=hotadd=percent + Only allow hotadd memory to preallocate page structures upto + percent of already available memory. + numa=hotadd=0 will disable hotadd memory. + +ACPI + + acpi=off Don't enable ACPI + acpi=ht Use ACPI boot table parsing, but don't enable ACPI + interpreter + acpi=force Force ACPI on (currently not needed) + + acpi=strict Disable out of spec ACPI workarounds. + + acpi_sci={edge,level,high,low} Set up ACPI SCI interrupt. + + acpi=noirq Don't route interrupts + +PCI + + pci=off Don't use PCI + pci=conf1 Use conf1 access. + pci=conf2 Use conf2 access. + pci=rom Assign ROMs. + pci=assign-busses Assign busses + pci=irqmask=MASK Set PCI interrupt mask to MASK + pci=lastbus=NUMBER Scan upto NUMBER busses, no matter what the mptable says. + pci=noacpi Don't use ACPI to set up PCI interrupt routing. + +IOMMU (input/output memory management unit) + + Currently four x86-64 PCI-DMA mapping implementations exist: + + 1. : use no hardware/software IOMMU at all + (e.g. because you have < 3 GB memory). + Kernel boot message: "PCI-DMA: Disabling IOMMU" + + 2. : AMD GART based hardware IOMMU. + Kernel boot message: "PCI-DMA: using GART IOMMU" + + 3. : Software IOMMU implementation. Used + e.g. if there is no hardware IOMMU in the system and it is need because + you have >3GB memory or told the kernel to us it (iommu=soft)) + Kernel boot message: "PCI-DMA: Using software bounce buffering + for IO (SWIOTLB)" + + 4. : IBM Calgary hardware IOMMU. Used in IBM + pSeries and xSeries servers. This hardware IOMMU supports DMA address + mapping with memory protection, etc. + Kernel boot message: "PCI-DMA: Using Calgary IOMMU" + + iommu=[][,noagp][,off][,force][,noforce][,leak[=] + [,memaper[=]][,merge][,forcesac][,fullflush][,nomerge] + [,noaperture][,calgary] + + General iommu options: + off Don't initialize and use any kind of IOMMU. + noforce Don't force hardware IOMMU usage when it is not needed. + (default). + force Force the use of the hardware IOMMU even when it is + not actually needed (e.g. because < 3 GB memory). + soft Use software bounce buffering (SWIOTLB) (default for + Intel machines). This can be used to prevent the usage + of an available hardware IOMMU. + + iommu options only relevant to the AMD GART hardware IOMMU: + Set the size of the remapping area in bytes. + allowed Overwrite iommu off workarounds for specific chipsets. + fullflush Flush IOMMU on each allocation (default). + nofullflush Don't use IOMMU fullflush. + leak Turn on simple iommu leak tracing (only when + CONFIG_IOMMU_LEAK is on). Default number of leak pages + is 20. + memaper[=] Allocate an own aperture over RAM with size 32MB<4GB. + DAC is used with 32-bit PCI to push a 64-bit address in + two cycles. When off all DMA over >4GB is forced through + an IOMMU or software bounce buffering. + nodac Forbid DAC mode, i.e. DMA >4GB. + panic Always panic when IOMMU overflows. + calgary Use the Calgary IOMMU if it is available + + iommu options only relevant to the software bounce buffering (SWIOTLB) IOMMU + implementation: + swiotlb=[,force] + Prereserve that many 128K pages for the software IO + bounce buffering. + force Force all IO through the software TLB. + + Settings for the IBM Calgary hardware IOMMU currently found in IBM + pSeries and xSeries machines: + + calgary=[64k,128k,256k,512k,1M,2M,4M,8M] + calgary=[translate_empty_slots] + calgary=[disable=] + panic Always panic when IOMMU overflows + + 64k,...,8M - Set the size of each PCI slot's translation table + when using the Calgary IOMMU. This is the size of the translation + table itself in main memory. The smallest table, 64k, covers an IO + space of 32MB; the largest, 8MB table, can cover an IO space of + 4GB. Normally the kernel will make the right choice by itself. + + translate_empty_slots - Enable translation even on slots that have + no devices attached to them, in case a device will be hotplugged + in the future. + + disable= - Disable translation on a given PHB. For + example, the built-in graphics adapter resides on the first bridge + (PCI bus number 0); if translation (isolation) is enabled on this + bridge, X servers that access the hardware directly from user + space might stop working. Use this option if you have devices that + are accessed from userspace directly on some PCI host bridge. + +Debugging + + oops=panic Always panic on oopses. Default is to just kill the process, + but there is a small probability of deadlocking the machine. + This will also cause panics on machine check exceptions. + Useful together with panic=30 to trigger a reboot. + + kstack=N Print N words from the kernel stack in oops dumps. + + pagefaulttrace Dump all page faults. Only useful for extreme debugging + and will create a lot of output. + + call_trace=[old|both|newfallback|new] + old: use old inexact backtracer + new: use new exact dwarf2 unwinder + both: print entries from both + newfallback: use new unwinder but fall back to old if it gets + stuck (default) + +Miscellaneous + + nogbpages + Do not use GB pages for kernel direct mappings. + gbpages + Use GB pages for kernel direct mappings. diff --git a/Documentation/x86/x86_64/cpu-hotplug-spec b/Documentation/x86/x86_64/cpu-hotplug-spec new file mode 100644 index 000000000000..3c23e0587db3 --- /dev/null +++ b/Documentation/x86/x86_64/cpu-hotplug-spec @@ -0,0 +1,21 @@ +Firmware support for CPU hotplug under Linux/x86-64 +--------------------------------------------------- + +Linux/x86-64 supports CPU hotplug now. For various reasons Linux wants to +know in advance of boot time the maximum number of CPUs that could be plugged +into the system. ACPI 3.0 currently has no official way to supply +this information from the firmware to the operating system. + +In ACPI each CPU needs an LAPIC object in the MADT table (5.2.11.5 in the +ACPI 3.0 specification). ACPI already has the concept of disabled LAPIC +objects by setting the Enabled bit in the LAPIC object to zero. + +For CPU hotplug Linux/x86-64 expects now that any possible future hotpluggable +CPU is already available in the MADT. If the CPU is not available yet +it should have its LAPIC Enabled bit set to 0. Linux will use the number +of disabled LAPICs to compute the maximum number of future CPUs. + +In the worst case the user can overwrite this choice using a command line +option (additional_cpus=...), but it is recommended to supply the correct +number (or a reasonable approximation of it, with erring towards more not less) +in the MADT to avoid manual configuration. diff --git a/Documentation/x86/x86_64/fake-numa-for-cpusets b/Documentation/x86/x86_64/fake-numa-for-cpusets new file mode 100644 index 000000000000..d1a985c5b00a --- /dev/null +++ b/Documentation/x86/x86_64/fake-numa-for-cpusets @@ -0,0 +1,66 @@ +Using numa=fake and CPUSets for Resource Management +Written by David Rientjes + +This document describes how the numa=fake x86_64 command-line option can be used +in conjunction with cpusets for coarse memory management. Using this feature, +you can create fake NUMA nodes that represent contiguous chunks of memory and +assign them to cpusets and their attached tasks. This is a way of limiting the +amount of system memory that are available to a certain class of tasks. + +For more information on the features of cpusets, see Documentation/cpusets.txt. +There are a number of different configurations you can use for your needs. For +more information on the numa=fake command line option and its various ways of +configuring fake nodes, see Documentation/x86_64/boot-options.txt. + +For the purposes of this introduction, we'll assume a very primitive NUMA +emulation setup of "numa=fake=4*512,". This will split our system memory into +four equal chunks of 512M each that we can now use to assign to cpusets. As +you become more familiar with using this combination for resource control, +you'll determine a better setup to minimize the number of nodes you have to deal +with. + +A machine may be split as follows with "numa=fake=4*512," as reported by dmesg: + + Faking node 0 at 0000000000000000-0000000020000000 (512MB) + Faking node 1 at 0000000020000000-0000000040000000 (512MB) + Faking node 2 at 0000000040000000-0000000060000000 (512MB) + Faking node 3 at 0000000060000000-0000000080000000 (512MB) + ... + On node 0 totalpages: 130975 + On node 1 totalpages: 131072 + On node 2 totalpages: 131072 + On node 3 totalpages: 131072 + +Now following the instructions for mounting the cpusets filesystem from +Documentation/cpusets.txt, you can assign fake nodes (i.e. contiguous memory +address spaces) to individual cpusets: + + [root@xroads /]# mkdir exampleset + [root@xroads /]# mount -t cpuset none exampleset + [root@xroads /]# mkdir exampleset/ddset + [root@xroads /]# cd exampleset/ddset + [root@xroads /exampleset/ddset]# echo 0-1 > cpus + [root@xroads /exampleset/ddset]# echo 0-1 > mems + +Now this cpuset, 'ddset', will only allowed access to fake nodes 0 and 1 for +memory allocations (1G). + +You can now assign tasks to these cpusets to limit the memory resources +available to them according to the fake nodes assigned as mems: + + [root@xroads /exampleset/ddset]# echo $$ > tasks + [root@xroads /exampleset/ddset]# dd if=/dev/zero of=tmp bs=1024 count=1G + [1] 13425 + +Notice the difference between the system memory usage as reported by +/proc/meminfo between the restricted cpuset case above and the unrestricted +case (i.e. running the same 'dd' command without assigning it to a fake NUMA +cpuset): + Unrestricted Restricted + MemTotal: 3091900 kB 3091900 kB + MemFree: 42113 kB 1513236 kB + +This allows for coarse memory management for the tasks you assign to particular +cpusets. Since cpusets can form a hierarchy, you can create some pretty +interesting combinations of use-cases for various classes of tasks for your +memory management needs. diff --git a/Documentation/x86/x86_64/kernel-stacks b/Documentation/x86/x86_64/kernel-stacks new file mode 100644 index 000000000000..5ad65d51fb95 --- /dev/null +++ b/Documentation/x86/x86_64/kernel-stacks @@ -0,0 +1,99 @@ +Most of the text from Keith Owens, hacked by AK + +x86_64 page size (PAGE_SIZE) is 4K. + +Like all other architectures, x86_64 has a kernel stack for every +active thread. These thread stacks are THREAD_SIZE (2*PAGE_SIZE) big. +These stacks contain useful data as long as a thread is alive or a +zombie. While the thread is in user space the kernel stack is empty +except for the thread_info structure at the bottom. + +In addition to the per thread stacks, there are specialized stacks +associated with each CPU. These stacks are only used while the kernel +is in control on that CPU; when a CPU returns to user space the +specialized stacks contain no useful data. The main CPU stacks are: + +* Interrupt stack. IRQSTACKSIZE + + Used for external hardware interrupts. If this is the first external + hardware interrupt (i.e. not a nested hardware interrupt) then the + kernel switches from the current task to the interrupt stack. Like + the split thread and interrupt stacks on i386 (with CONFIG_4KSTACKS), + this gives more room for kernel interrupt processing without having + to increase the size of every per thread stack. + + The interrupt stack is also used when processing a softirq. + +Switching to the kernel interrupt stack is done by software based on a +per CPU interrupt nest counter. This is needed because x86-64 "IST" +hardware stacks cannot nest without races. + +x86_64 also has a feature which is not available on i386, the ability +to automatically switch to a new stack for designated events such as +double fault or NMI, which makes it easier to handle these unusual +events on x86_64. This feature is called the Interrupt Stack Table +(IST). There can be up to 7 IST entries per CPU. The IST code is an +index into the Task State Segment (TSS). The IST entries in the TSS +point to dedicated stacks; each stack can be a different size. + +An IST is selected by a non-zero value in the IST field of an +interrupt-gate descriptor. When an interrupt occurs and the hardware +loads such a descriptor, the hardware automatically sets the new stack +pointer based on the IST value, then invokes the interrupt handler. If +software wants to allow nested IST interrupts then the handler must +adjust the IST values on entry to and exit from the interrupt handler. +(This is occasionally done, e.g. for debug exceptions.) + +Events with different IST codes (i.e. with different stacks) can be +nested. For example, a debug interrupt can safely be interrupted by an +NMI. arch/x86_64/kernel/entry.S::paranoidentry adjusts the stack +pointers on entry to and exit from all IST events, in theory allowing +IST events with the same code to be nested. However in most cases, the +stack size allocated to an IST assumes no nesting for the same code. +If that assumption is ever broken then the stacks will become corrupt. + +The currently assigned IST stacks are :- + +* STACKFAULT_STACK. EXCEPTION_STKSZ (PAGE_SIZE). + + Used for interrupt 12 - Stack Fault Exception (#SS). + + This allows the CPU to recover from invalid stack segments. Rarely + happens. + +* DOUBLEFAULT_STACK. EXCEPTION_STKSZ (PAGE_SIZE). + + Used for interrupt 8 - Double Fault Exception (#DF). + + Invoked when handling one exception causes another exception. Happens + when the kernel is very confused (e.g. kernel stack pointer corrupt). + Using a separate stack allows the kernel to recover from it well enough + in many cases to still output an oops. + +* NMI_STACK. EXCEPTION_STKSZ (PAGE_SIZE). + + Used for non-maskable interrupts (NMI). + + NMI can be delivered at any time, including when the kernel is in the + middle of switching stacks. Using IST for NMI events avoids making + assumptions about the previous state of the kernel stack. + +* DEBUG_STACK. DEBUG_STKSZ + + Used for hardware debug interrupts (interrupt 1) and for software + debug interrupts (INT3). + + When debugging a kernel, debug interrupts (both hardware and + software) can occur at any time. Using IST for these interrupts + avoids making assumptions about the previous state of the kernel + stack. + +* MCE_STACK. EXCEPTION_STKSZ (PAGE_SIZE). + + Used for interrupt 18 - Machine Check Exception (#MC). + + MCE can be delivered at any time, including when the kernel is in the + middle of switching stacks. Using IST for MCE events avoids making + assumptions about the previous state of the kernel stack. + +For more details see the Intel IA32 or AMD AMD64 architecture manuals. diff --git a/Documentation/x86/x86_64/machinecheck b/Documentation/x86/x86_64/machinecheck new file mode 100644 index 000000000000..a05e58e7b159 --- /dev/null +++ b/Documentation/x86/x86_64/machinecheck @@ -0,0 +1,77 @@ + +Configurable sysfs parameters for the x86-64 machine check code. + +Machine checks report internal hardware error conditions detected +by the CPU. Uncorrected errors typically cause a machine check +(often with panic), corrected ones cause a machine check log entry. + +Machine checks are organized in banks (normally associated with +a hardware subsystem) and subevents in a bank. The exact meaning +of the banks and subevent is CPU specific. + +mcelog knows how to decode them. + +When you see the "Machine check errors logged" message in the system +log then mcelog should run to collect and decode machine check entries +from /dev/mcelog. Normally mcelog should be run regularly from a cronjob. + +Each CPU has a directory in /sys/devices/system/machinecheck/machinecheckN +(N = CPU number) + +The directory contains some configurable entries: + +Entries: + +bankNctl +(N bank number) + 64bit Hex bitmask enabling/disabling specific subevents for bank N + When a bit in the bitmask is zero then the respective + subevent will not be reported. + By default all events are enabled. + Note that BIOS maintain another mask to disable specific events + per bank. This is not visible here + +The following entries appear for each CPU, but they are truly shared +between all CPUs. + +check_interval + How often to poll for corrected machine check errors, in seconds + (Note output is hexademical). Default 5 minutes. When the poller + finds MCEs it triggers an exponential speedup (poll more often) on + the polling interval. When the poller stops finding MCEs, it + triggers an exponential backoff (poll less often) on the polling + interval. The check_interval variable is both the initial and + maximum polling interval. + +tolerant + Tolerance level. When a machine check exception occurs for a non + corrected machine check the kernel can take different actions. + Since machine check exceptions can happen any time it is sometimes + risky for the kernel to kill a process because it defies + normal kernel locking rules. The tolerance level configures + how hard the kernel tries to recover even at some risk of + deadlock. Higher tolerant values trade potentially better uptime + with the risk of a crash or even corruption (for tolerant >= 3). + + 0: always panic on uncorrected errors, log corrected errors + 1: panic or SIGBUS on uncorrected errors, log corrected errors + 2: SIGBUS or log uncorrected errors, log corrected errors + 3: never panic or SIGBUS, log all errors (for testing only) + + Default: 1 + + Note this only makes a difference if the CPU allows recovery + from a machine check exception. Current x86 CPUs generally do not. + +trigger + Program to run when a machine check event is detected. + This is an alternative to running mcelog regularly from cron + and allows to detect events faster. + +TBD document entries for AMD threshold interrupt configuration + +For more details about the x86 machine check architecture +see the Intel and AMD architecture manuals from their developer websites. + +For more details about the architecture see +see http://one.firstfloor.org/~andi/mce.pdf diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt new file mode 100644 index 000000000000..b89b6d2bebfa --- /dev/null +++ b/Documentation/x86/x86_64/mm.txt @@ -0,0 +1,29 @@ + + + +Virtual memory map with 4 level page tables: + +0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm +hole caused by [48:63] sign extension +ffff800000000000 - ffff80ffffffffff (=40 bits) guard hole +ffff810000000000 - ffffc0ffffffffff (=46 bits) direct mapping of all phys. memory +ffffc10000000000 - ffffc1ffffffffff (=40 bits) hole +ffffc20000000000 - ffffe1ffffffffff (=45 bits) vmalloc/ioremap space +ffffe20000000000 - ffffe2ffffffffff (=40 bits) virtual memory map (1TB) +... unused hole ... +ffffffff80000000 - ffffffff82800000 (=40 MB) kernel text mapping, from phys 0 +... unused hole ... +ffffffff88000000 - fffffffffff00000 (=1919 MB) module mapping space + +The direct mapping covers all memory in the system up to the highest +memory address (this means in some cases it can also include PCI memory +holes). + +vmalloc space is lazily synchronized into the different PML4 pages of +the processes using the page fault handler, with init_level4_pgt as +reference. + +Current X86-64 implementations only support 40 bits of address space, +but we support up to 46 bits. This expands into MBZ space in the page tables. + +-Andi Kleen, Jul 2004 diff --git a/Documentation/x86/x86_64/uefi.txt b/Documentation/x86/x86_64/uefi.txt new file mode 100644 index 000000000000..7d77120a5184 --- /dev/null +++ b/Documentation/x86/x86_64/uefi.txt @@ -0,0 +1,38 @@ +General note on [U]EFI x86_64 support +------------------------------------- + +The nomenclature EFI and UEFI are used interchangeably in this document. + +Although the tools below are _not_ needed for building the kernel, +the needed bootloader support and associated tools for x86_64 platforms +with EFI firmware and specifications are listed below. + +1. UEFI specification: http://www.uefi.org + +2. Booting Linux kernel on UEFI x86_64 platform requires bootloader + support. Elilo with x86_64 support can be used. + +3. x86_64 platform with EFI/UEFI firmware. + +Mechanics: +--------- +- Build the kernel with the following configuration. + CONFIG_FB_EFI=y + CONFIG_FRAMEBUFFER_CONSOLE=y + If EFI runtime services are expected, the following configuration should + be selected. + CONFIG_EFI=y + CONFIG_EFI_VARS=y or m # optional +- Create a VFAT partition on the disk +- Copy the following to the VFAT partition: + elilo bootloader with x86_64 support, elilo configuration file, + kernel image built in first step and corresponding + initrd. Instructions on building elilo and its dependencies + can be found in the elilo sourceforge project. +- Boot to EFI shell and invoke elilo choosing the kernel image built + in first step. +- If some or all EFI runtime services don't work, you can try following + kernel command line parameters to turn off some or all EFI runtime + services. + noefi turn off all EFI runtime services + reboot_type=k turn off EFI reboot runtime service diff --git a/Documentation/x86_64/00-INDEX b/Documentation/x86_64/00-INDEX deleted file mode 100644 index 92fc20ab5f0e..000000000000 --- a/Documentation/x86_64/00-INDEX +++ /dev/null @@ -1,16 +0,0 @@ -00-INDEX - - This file -boot-options.txt - - AMD64-specific boot options. -cpu-hotplug-spec - - Firmware support for CPU hotplug under Linux/x86-64 -fake-numa-for-cpusets - - Using numa=fake and CPUSets for Resource Management -kernel-stacks - - Context-specific per-processor interrupt stacks. -machinecheck - - Configurable sysfs parameters for the x86-64 machine check code. -mm.txt - - Memory layout of x86-64 (4 level page tables, 46 bits physical). -uefi.txt - - Booting Linux via Unified Extensible Firmware Interface. diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt deleted file mode 100644 index b0c7b6c4abda..000000000000 --- a/Documentation/x86_64/boot-options.txt +++ /dev/null @@ -1,314 +0,0 @@ -AMD64 specific boot options - -There are many others (usually documented in driver documentation), but -only the AMD64 specific ones are listed here. - -Machine check - - mce=off disable machine check - mce=bootlog Enable logging of machine checks left over from booting. - Disabled by default on AMD because some BIOS leave bogus ones. - If your BIOS doesn't do that it's a good idea to enable though - to make sure you log even machine check events that result - in a reboot. On Intel systems it is enabled by default. - mce=nobootlog - Disable boot machine check logging. - mce=tolerancelevel (number) - 0: always panic on uncorrected errors, log corrected errors - 1: panic or SIGBUS on uncorrected errors, log corrected errors - 2: SIGBUS or log uncorrected errors, log corrected errors - 3: never panic or SIGBUS, log all errors (for testing only) - Default is 1 - Can be also set using sysfs which is preferable. - - nomce (for compatibility with i386): same as mce=off - - Everything else is in sysfs now. - -APICs - - apic Use IO-APIC. Default - - noapic Don't use the IO-APIC. - - disableapic Don't use the local APIC - - nolapic Don't use the local APIC (alias for i386 compatibility) - - pirq=... See Documentation/i386/IO-APIC.txt - - noapictimer Don't set up the APIC timer - - no_timer_check Don't check the IO-APIC timer. This can work around - problems with incorrect timer initialization on some boards. - - apicmaintimer Run time keeping from the local APIC timer instead - of using the PIT/HPET interrupt for this. This is useful - when the PIT/HPET interrupts are unreliable. - - noapicmaintimer Don't do time keeping using the APIC timer. - Useful when this option was auto selected, but doesn't work. - - apicpmtimer - Do APIC timer calibration using the pmtimer. Implies - apicmaintimer. Useful when your PIT timer is totally - broken. - - disable_8254_timer / enable_8254_timer - Enable interrupt 0 timer routing over the 8254 in addition to over - the IO-APIC. The kernel tries to set a sensible default. - -Early Console - - syntax: earlyprintk=vga - earlyprintk=serial[,ttySn[,baudrate]] - - The early console is useful when the kernel crashes before the - normal console is initialized. It is not enabled by - default because it has some cosmetic problems. - Append ,keep to not disable it when the real console takes over. - Only vga or serial at a time, not both. - Currently only ttyS0 and ttyS1 are supported. - Interaction with the standard serial driver is not very good. - The VGA output is eventually overwritten by the real console. - -Timing - - notsc - Don't use the CPU time stamp counter to read the wall time. - This can be used to work around timing problems on multiprocessor systems - with not properly synchronized CPUs. - - report_lost_ticks - Report when timer interrupts are lost because some code turned off - interrupts for too long. - - nmi_watchdog=NUMBER[,panic] - NUMBER can be: - 0 don't use an NMI watchdog - 1 use the IO-APIC timer for the NMI watchdog - 2 use the local APIC for the NMI watchdog using a performance counter. Note - This will use one performance counter and the local APIC's performance - vector. - When panic is specified panic when an NMI watchdog timeout occurs. - This is useful when you use a panic=... timeout and need the box - quickly up again. - - nohpet - Don't use the HPET timer. - -Idle loop - - idle=poll - Don't do power saving in the idle loop using HLT, but poll for rescheduling - event. This will make the CPUs eat a lot more power, but may be useful - to get slightly better performance in multiprocessor benchmarks. It also - makes some profiling using performance counters more accurate. - Please note that on systems with MONITOR/MWAIT support (like Intel EM64T - CPUs) this option has no performance advantage over the normal idle loop. - It may also interact badly with hyperthreading. - -Rebooting - - reboot=b[ios] | t[riple] | k[bd] | a[cpi] | e[fi] [, [w]arm | [c]old] - bios Use the CPU reboot vector for warm reset - warm Don't set the cold reboot flag - cold Set the cold reboot flag - triple Force a triple fault (init) - kbd Use the keyboard controller. cold reset (default) - acpi Use the ACPI RESET_REG in the FADT. If ACPI is not configured or the - ACPI reset does not work, the reboot path attempts the reset using - the keyboard controller. - efi Use efi reset_system runtime service. If EFI is not configured or the - EFI reset does not work, the reboot path attempts the reset using - the keyboard controller. - - Using warm reset will be much faster especially on big memory - systems because the BIOS will not go through the memory check. - Disadvantage is that not all hardware will be completely reinitialized - on reboot so there may be boot problems on some systems. - - reboot=force - - Don't stop other CPUs on reboot. This can make reboot more reliable - in some cases. - -Non Executable Mappings - - noexec=on|off - - on Enable(default) - off Disable - -SMP - - additional_cpus=NUM Allow NUM more CPUs for hotplug - (defaults are specified by the BIOS, see Documentation/x86_64/cpu-hotplug-spec) - -NUMA - - numa=off Only set up a single NUMA node spanning all memory. - - numa=noacpi Don't parse the SRAT table for NUMA setup - - numa=fake=CMDLINE - If a number, fakes CMDLINE nodes and ignores NUMA setup of the - actual machine. Otherwise, system memory is configured - depending on the sizes and coefficients listed. For example: - numa=fake=2*512,1024,4*256,*128 - gives two 512M nodes, a 1024M node, four 256M nodes, and the - rest split into 128M chunks. If the last character of CMDLINE - is a *, the remaining memory is divided up equally among its - coefficient: - numa=fake=2*512,2* - gives two 512M nodes and the rest split into two nodes. - Otherwise, the remaining system RAM is allocated to an - additional node. - - numa=hotadd=percent - Only allow hotadd memory to preallocate page structures upto - percent of already available memory. - numa=hotadd=0 will disable hotadd memory. - -ACPI - - acpi=off Don't enable ACPI - acpi=ht Use ACPI boot table parsing, but don't enable ACPI - interpreter - acpi=force Force ACPI on (currently not needed) - - acpi=strict Disable out of spec ACPI workarounds. - - acpi_sci={edge,level,high,low} Set up ACPI SCI interrupt. - - acpi=noirq Don't route interrupts - -PCI - - pci=off Don't use PCI - pci=conf1 Use conf1 access. - pci=conf2 Use conf2 access. - pci=rom Assign ROMs. - pci=assign-busses Assign busses - pci=irqmask=MASK Set PCI interrupt mask to MASK - pci=lastbus=NUMBER Scan upto NUMBER busses, no matter what the mptable says. - pci=noacpi Don't use ACPI to set up PCI interrupt routing. - -IOMMU (input/output memory management unit) - - Currently four x86-64 PCI-DMA mapping implementations exist: - - 1. : use no hardware/software IOMMU at all - (e.g. because you have < 3 GB memory). - Kernel boot message: "PCI-DMA: Disabling IOMMU" - - 2. : AMD GART based hardware IOMMU. - Kernel boot message: "PCI-DMA: using GART IOMMU" - - 3. : Software IOMMU implementation. Used - e.g. if there is no hardware IOMMU in the system and it is need because - you have >3GB memory or told the kernel to us it (iommu=soft)) - Kernel boot message: "PCI-DMA: Using software bounce buffering - for IO (SWIOTLB)" - - 4. : IBM Calgary hardware IOMMU. Used in IBM - pSeries and xSeries servers. This hardware IOMMU supports DMA address - mapping with memory protection, etc. - Kernel boot message: "PCI-DMA: Using Calgary IOMMU" - - iommu=[][,noagp][,off][,force][,noforce][,leak[=] - [,memaper[=]][,merge][,forcesac][,fullflush][,nomerge] - [,noaperture][,calgary] - - General iommu options: - off Don't initialize and use any kind of IOMMU. - noforce Don't force hardware IOMMU usage when it is not needed. - (default). - force Force the use of the hardware IOMMU even when it is - not actually needed (e.g. because < 3 GB memory). - soft Use software bounce buffering (SWIOTLB) (default for - Intel machines). This can be used to prevent the usage - of an available hardware IOMMU. - - iommu options only relevant to the AMD GART hardware IOMMU: - Set the size of the remapping area in bytes. - allowed Overwrite iommu off workarounds for specific chipsets. - fullflush Flush IOMMU on each allocation (default). - nofullflush Don't use IOMMU fullflush. - leak Turn on simple iommu leak tracing (only when - CONFIG_IOMMU_LEAK is on). Default number of leak pages - is 20. - memaper[=] Allocate an own aperture over RAM with size 32MB<4GB. - DAC is used with 32-bit PCI to push a 64-bit address in - two cycles. When off all DMA over >4GB is forced through - an IOMMU or software bounce buffering. - nodac Forbid DAC mode, i.e. DMA >4GB. - panic Always panic when IOMMU overflows. - calgary Use the Calgary IOMMU if it is available - - iommu options only relevant to the software bounce buffering (SWIOTLB) IOMMU - implementation: - swiotlb=[,force] - Prereserve that many 128K pages for the software IO - bounce buffering. - force Force all IO through the software TLB. - - Settings for the IBM Calgary hardware IOMMU currently found in IBM - pSeries and xSeries machines: - - calgary=[64k,128k,256k,512k,1M,2M,4M,8M] - calgary=[translate_empty_slots] - calgary=[disable=] - panic Always panic when IOMMU overflows - - 64k,...,8M - Set the size of each PCI slot's translation table - when using the Calgary IOMMU. This is the size of the translation - table itself in main memory. The smallest table, 64k, covers an IO - space of 32MB; the largest, 8MB table, can cover an IO space of - 4GB. Normally the kernel will make the right choice by itself. - - translate_empty_slots - Enable translation even on slots that have - no devices attached to them, in case a device will be hotplugged - in the future. - - disable= - Disable translation on a given PHB. For - example, the built-in graphics adapter resides on the first bridge - (PCI bus number 0); if translation (isolation) is enabled on this - bridge, X servers that access the hardware directly from user - space might stop working. Use this option if you have devices that - are accessed from userspace directly on some PCI host bridge. - -Debugging - - oops=panic Always panic on oopses. Default is to just kill the process, - but there is a small probability of deadlocking the machine. - This will also cause panics on machine check exceptions. - Useful together with panic=30 to trigger a reboot. - - kstack=N Print N words from the kernel stack in oops dumps. - - pagefaulttrace Dump all page faults. Only useful for extreme debugging - and will create a lot of output. - - call_trace=[old|both|newfallback|new] - old: use old inexact backtracer - new: use new exact dwarf2 unwinder - both: print entries from both - newfallback: use new unwinder but fall back to old if it gets - stuck (default) - -Miscellaneous - - nogbpages - Do not use GB pages for kernel direct mappings. - gbpages - Use GB pages for kernel direct mappings. diff --git a/Documentation/x86_64/cpu-hotplug-spec b/Documentation/x86_64/cpu-hotplug-spec deleted file mode 100644 index 3c23e0587db3..000000000000 --- a/Documentation/x86_64/cpu-hotplug-spec +++ /dev/null @@ -1,21 +0,0 @@ -Firmware support for CPU hotplug under Linux/x86-64 ---------------------------------------------------- - -Linux/x86-64 supports CPU hotplug now. For various reasons Linux wants to -know in advance of boot time the maximum number of CPUs that could be plugged -into the system. ACPI 3.0 currently has no official way to supply -this information from the firmware to the operating system. - -In ACPI each CPU needs an LAPIC object in the MADT table (5.2.11.5 in the -ACPI 3.0 specification). ACPI already has the concept of disabled LAPIC -objects by setting the Enabled bit in the LAPIC object to zero. - -For CPU hotplug Linux/x86-64 expects now that any possible future hotpluggable -CPU is already available in the MADT. If the CPU is not available yet -it should have its LAPIC Enabled bit set to 0. Linux will use the number -of disabled LAPICs to compute the maximum number of future CPUs. - -In the worst case the user can overwrite this choice using a command line -option (additional_cpus=...), but it is recommended to supply the correct -number (or a reasonable approximation of it, with erring towards more not less) -in the MADT to avoid manual configuration. diff --git a/Documentation/x86_64/fake-numa-for-cpusets b/Documentation/x86_64/fake-numa-for-cpusets deleted file mode 100644 index d1a985c5b00a..000000000000 --- a/Documentation/x86_64/fake-numa-for-cpusets +++ /dev/null @@ -1,66 +0,0 @@ -Using numa=fake and CPUSets for Resource Management -Written by David Rientjes - -This document describes how the numa=fake x86_64 command-line option can be used -in conjunction with cpusets for coarse memory management. Using this feature, -you can create fake NUMA nodes that represent contiguous chunks of memory and -assign them to cpusets and their attached tasks. This is a way of limiting the -amount of system memory that are available to a certain class of tasks. - -For more information on the features of cpusets, see Documentation/cpusets.txt. -There are a number of different configurations you can use for your needs. For -more information on the numa=fake command line option and its various ways of -configuring fake nodes, see Documentation/x86_64/boot-options.txt. - -For the purposes of this introduction, we'll assume a very primitive NUMA -emulation setup of "numa=fake=4*512,". This will split our system memory into -four equal chunks of 512M each that we can now use to assign to cpusets. As -you become more familiar with using this combination for resource control, -you'll determine a better setup to minimize the number of nodes you have to deal -with. - -A machine may be split as follows with "numa=fake=4*512," as reported by dmesg: - - Faking node 0 at 0000000000000000-0000000020000000 (512MB) - Faking node 1 at 0000000020000000-0000000040000000 (512MB) - Faking node 2 at 0000000040000000-0000000060000000 (512MB) - Faking node 3 at 0000000060000000-0000000080000000 (512MB) - ... - On node 0 totalpages: 130975 - On node 1 totalpages: 131072 - On node 2 totalpages: 131072 - On node 3 totalpages: 131072 - -Now following the instructions for mounting the cpusets filesystem from -Documentation/cpusets.txt, you can assign fake nodes (i.e. contiguous memory -address spaces) to individual cpusets: - - [root@xroads /]# mkdir exampleset - [root@xroads /]# mount -t cpuset none exampleset - [root@xroads /]# mkdir exampleset/ddset - [root@xroads /]# cd exampleset/ddset - [root@xroads /exampleset/ddset]# echo 0-1 > cpus - [root@xroads /exampleset/ddset]# echo 0-1 > mems - -Now this cpuset, 'ddset', will only allowed access to fake nodes 0 and 1 for -memory allocations (1G). - -You can now assign tasks to these cpusets to limit the memory resources -available to them according to the fake nodes assigned as mems: - - [root@xroads /exampleset/ddset]# echo $$ > tasks - [root@xroads /exampleset/ddset]# dd if=/dev/zero of=tmp bs=1024 count=1G - [1] 13425 - -Notice the difference between the system memory usage as reported by -/proc/meminfo between the restricted cpuset case above and the unrestricted -case (i.e. running the same 'dd' command without assigning it to a fake NUMA -cpuset): - Unrestricted Restricted - MemTotal: 3091900 kB 3091900 kB - MemFree: 42113 kB 1513236 kB - -This allows for coarse memory management for the tasks you assign to particular -cpusets. Since cpusets can form a hierarchy, you can create some pretty -interesting combinations of use-cases for various classes of tasks for your -memory management needs. diff --git a/Documentation/x86_64/kernel-stacks b/Documentation/x86_64/kernel-stacks deleted file mode 100644 index 5ad65d51fb95..000000000000 --- a/Documentation/x86_64/kernel-stacks +++ /dev/null @@ -1,99 +0,0 @@ -Most of the text from Keith Owens, hacked by AK - -x86_64 page size (PAGE_SIZE) is 4K. - -Like all other architectures, x86_64 has a kernel stack for every -active thread. These thread stacks are THREAD_SIZE (2*PAGE_SIZE) big. -These stacks contain useful data as long as a thread is alive or a -zombie. While the thread is in user space the kernel stack is empty -except for the thread_info structure at the bottom. - -In addition to the per thread stacks, there are specialized stacks -associated with each CPU. These stacks are only used while the kernel -is in control on that CPU; when a CPU returns to user space the -specialized stacks contain no useful data. The main CPU stacks are: - -* Interrupt stack. IRQSTACKSIZE - - Used for external hardware interrupts. If this is the first external - hardware interrupt (i.e. not a nested hardware interrupt) then the - kernel switches from the current task to the interrupt stack. Like - the split thread and interrupt stacks on i386 (with CONFIG_4KSTACKS), - this gives more room for kernel interrupt processing without having - to increase the size of every per thread stack. - - The interrupt stack is also used when processing a softirq. - -Switching to the kernel interrupt stack is done by software based on a -per CPU interrupt nest counter. This is needed because x86-64 "IST" -hardware stacks cannot nest without races. - -x86_64 also has a feature which is not available on i386, the ability -to automatically switch to a new stack for designated events such as -double fault or NMI, which makes it easier to handle these unusual -events on x86_64. This feature is called the Interrupt Stack Table -(IST). There can be up to 7 IST entries per CPU. The IST code is an -index into the Task State Segment (TSS). The IST entries in the TSS -point to dedicated stacks; each stack can be a different size. - -An IST is selected by a non-zero value in the IST field of an -interrupt-gate descriptor. When an interrupt occurs and the hardware -loads such a descriptor, the hardware automatically sets the new stack -pointer based on the IST value, then invokes the interrupt handler. If -software wants to allow nested IST interrupts then the handler must -adjust the IST values on entry to and exit from the interrupt handler. -(This is occasionally done, e.g. for debug exceptions.) - -Events with different IST codes (i.e. with different stacks) can be -nested. For example, a debug interrupt can safely be interrupted by an -NMI. arch/x86_64/kernel/entry.S::paranoidentry adjusts the stack -pointers on entry to and exit from all IST events, in theory allowing -IST events with the same code to be nested. However in most cases, the -stack size allocated to an IST assumes no nesting for the same code. -If that assumption is ever broken then the stacks will become corrupt. - -The currently assigned IST stacks are :- - -* STACKFAULT_STACK. EXCEPTION_STKSZ (PAGE_SIZE). - - Used for interrupt 12 - Stack Fault Exception (#SS). - - This allows the CPU to recover from invalid stack segments. Rarely - happens. - -* DOUBLEFAULT_STACK. EXCEPTION_STKSZ (PAGE_SIZE). - - Used for interrupt 8 - Double Fault Exception (#DF). - - Invoked when handling one exception causes another exception. Happens - when the kernel is very confused (e.g. kernel stack pointer corrupt). - Using a separate stack allows the kernel to recover from it well enough - in many cases to still output an oops. - -* NMI_STACK. EXCEPTION_STKSZ (PAGE_SIZE). - - Used for non-maskable interrupts (NMI). - - NMI can be delivered at any time, including when the kernel is in the - middle of switching stacks. Using IST for NMI events avoids making - assumptions about the previous state of the kernel stack. - -* DEBUG_STACK. DEBUG_STKSZ - - Used for hardware debug interrupts (interrupt 1) and for software - debug interrupts (INT3). - - When debugging a kernel, debug interrupts (both hardware and - software) can occur at any time. Using IST for these interrupts - avoids making assumptions about the previous state of the kernel - stack. - -* MCE_STACK. EXCEPTION_STKSZ (PAGE_SIZE). - - Used for interrupt 18 - Machine Check Exception (#MC). - - MCE can be delivered at any time, including when the kernel is in the - middle of switching stacks. Using IST for MCE events avoids making - assumptions about the previous state of the kernel stack. - -For more details see the Intel IA32 or AMD AMD64 architecture manuals. diff --git a/Documentation/x86_64/machinecheck b/Documentation/x86_64/machinecheck deleted file mode 100644 index a05e58e7b159..000000000000 --- a/Documentation/x86_64/machinecheck +++ /dev/null @@ -1,77 +0,0 @@ - -Configurable sysfs parameters for the x86-64 machine check code. - -Machine checks report internal hardware error conditions detected -by the CPU. Uncorrected errors typically cause a machine check -(often with panic), corrected ones cause a machine check log entry. - -Machine checks are organized in banks (normally associated with -a hardware subsystem) and subevents in a bank. The exact meaning -of the banks and subevent is CPU specific. - -mcelog knows how to decode them. - -When you see the "Machine check errors logged" message in the system -log then mcelog should run to collect and decode machine check entries -from /dev/mcelog. Normally mcelog should be run regularly from a cronjob. - -Each CPU has a directory in /sys/devices/system/machinecheck/machinecheckN -(N = CPU number) - -The directory contains some configurable entries: - -Entries: - -bankNctl -(N bank number) - 64bit Hex bitmask enabling/disabling specific subevents for bank N - When a bit in the bitmask is zero then the respective - subevent will not be reported. - By default all events are enabled. - Note that BIOS maintain another mask to disable specific events - per bank. This is not visible here - -The following entries appear for each CPU, but they are truly shared -between all CPUs. - -check_interval - How often to poll for corrected machine check errors, in seconds - (Note output is hexademical). Default 5 minutes. When the poller - finds MCEs it triggers an exponential speedup (poll more often) on - the polling interval. When the poller stops finding MCEs, it - triggers an exponential backoff (poll less often) on the polling - interval. The check_interval variable is both the initial and - maximum polling interval. - -tolerant - Tolerance level. When a machine check exception occurs for a non - corrected machine check the kernel can take different actions. - Since machine check exceptions can happen any time it is sometimes - risky for the kernel to kill a process because it defies - normal kernel locking rules. The tolerance level configures - how hard the kernel tries to recover even at some risk of - deadlock. Higher tolerant values trade potentially better uptime - with the risk of a crash or even corruption (for tolerant >= 3). - - 0: always panic on uncorrected errors, log corrected errors - 1: panic or SIGBUS on uncorrected errors, log corrected errors - 2: SIGBUS or log uncorrected errors, log corrected errors - 3: never panic or SIGBUS, log all errors (for testing only) - - Default: 1 - - Note this only makes a difference if the CPU allows recovery - from a machine check exception. Current x86 CPUs generally do not. - -trigger - Program to run when a machine check event is detected. - This is an alternative to running mcelog regularly from cron - and allows to detect events faster. - -TBD document entries for AMD threshold interrupt configuration - -For more details about the x86 machine check architecture -see the Intel and AMD architecture manuals from their developer websites. - -For more details about the architecture see -see http://one.firstfloor.org/~andi/mce.pdf diff --git a/Documentation/x86_64/mm.txt b/Documentation/x86_64/mm.txt deleted file mode 100644 index b89b6d2bebfa..000000000000 --- a/Documentation/x86_64/mm.txt +++ /dev/null @@ -1,29 +0,0 @@ - - - -Virtual memory map with 4 level page tables: - -0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm -hole caused by [48:63] sign extension -ffff800000000000 - ffff80ffffffffff (=40 bits) guard hole -ffff810000000000 - ffffc0ffffffffff (=46 bits) direct mapping of all phys. memory -ffffc10000000000 - ffffc1ffffffffff (=40 bits) hole -ffffc20000000000 - ffffe1ffffffffff (=45 bits) vmalloc/ioremap space -ffffe20000000000 - ffffe2ffffffffff (=40 bits) virtual memory map (1TB) -... unused hole ... -ffffffff80000000 - ffffffff82800000 (=40 MB) kernel text mapping, from phys 0 -... unused hole ... -ffffffff88000000 - fffffffffff00000 (=1919 MB) module mapping space - -The direct mapping covers all memory in the system up to the highest -memory address (this means in some cases it can also include PCI memory -holes). - -vmalloc space is lazily synchronized into the different PML4 pages of -the processes using the page fault handler, with init_level4_pgt as -reference. - -Current X86-64 implementations only support 40 bits of address space, -but we support up to 46 bits. This expands into MBZ space in the page tables. - --Andi Kleen, Jul 2004 diff --git a/Documentation/x86_64/uefi.txt b/Documentation/x86_64/uefi.txt deleted file mode 100644 index 7d77120a5184..000000000000 --- a/Documentation/x86_64/uefi.txt +++ /dev/null @@ -1,38 +0,0 @@ -General note on [U]EFI x86_64 support -------------------------------------- - -The nomenclature EFI and UEFI are used interchangeably in this document. - -Although the tools below are _not_ needed for building the kernel, -the needed bootloader support and associated tools for x86_64 platforms -with EFI firmware and specifications are listed below. - -1. UEFI specification: http://www.uefi.org - -2. Booting Linux kernel on UEFI x86_64 platform requires bootloader - support. Elilo with x86_64 support can be used. - -3. x86_64 platform with EFI/UEFI firmware. - -Mechanics: ---------- -- Build the kernel with the following configuration. - CONFIG_FB_EFI=y - CONFIG_FRAMEBUFFER_CONSOLE=y - If EFI runtime services are expected, the following configuration should - be selected. - CONFIG_EFI=y - CONFIG_EFI_VARS=y or m # optional -- Create a VFAT partition on the disk -- Copy the following to the VFAT partition: - elilo bootloader with x86_64 support, elilo configuration file, - kernel image built in first step and corresponding - initrd. Instructions on building elilo and its dependencies - can be found in the elilo sourceforge project. -- Boot to EFI shell and invoke elilo choosing the kernel image built - in first step. -- If some or all EFI runtime services don't work, you can try following - kernel command line parameters to turn off some or all EFI runtime - services. - noefi turn off all EFI runtime services - reboot_type=k turn off EFI reboot runtime service -- cgit v1.2.3 From 18404756765c713a0be4eb1082920c04822ce588 Mon Sep 17 00:00:00 2001 From: Max Krasnyansky Date: Thu, 29 May 2008 11:02:52 -0700 Subject: genirq: Expose default irq affinity mask (take 3) Current IRQ affinity interface does not provide a way to set affinity for the IRQs that will be allocated/activated in the future. This patch creates /proc/irq/default_smp_affinity that lets users set default affinity mask for the newly allocated IRQs. Changing the default does not affect affinity masks for the currently active IRQs, they have to be changed explicitly. Updated based on Paul J's comments and added some more documentation. Signed-off-by: Max Krasnyansky Cc: pj@sgi.com Cc: a.p.zijlstra@chello.nl Cc: tglx@linutronix.de Cc: rdunlap@xenotime.net Cc: mingo@elte.hu Signed-off-by: Thomas Gleixner --- Documentation/IRQ-affinity.txt | 37 ++++++++++++++++++++++++++++--------- Documentation/filesystems/proc.txt | 29 ++++++++++++++++++----------- 2 files changed, 46 insertions(+), 20 deletions(-) (limited to 'Documentation') diff --git a/Documentation/IRQ-affinity.txt b/Documentation/IRQ-affinity.txt index 938d7dd05490..b4a615b78403 100644 --- a/Documentation/IRQ-affinity.txt +++ b/Documentation/IRQ-affinity.txt @@ -1,17 +1,26 @@ +ChangeLog: + Started by Ingo Molnar + Update by Max Krasnyansky -SMP IRQ affinity, started by Ingo Molnar - +SMP IRQ affinity /proc/irq/IRQ#/smp_affinity specifies which target CPUs are permitted for a given IRQ source. It's a bitmask of allowed CPUs. It's not allowed to turn off all CPUs, and if an IRQ controller does not support IRQ affinity then the value will not change from the default 0xffffffff. +/proc/irq/default_smp_affinity specifies default affinity mask that applies +to all non-active IRQs. Once IRQ is allocated/activated its affinity bitmask +will be set to the default mask. It can then be changed as described above. +Default mask is 0xffffffff. + Here is an example of restricting IRQ44 (eth1) to CPU0-3 then restricting -the IRQ to CPU4-7 (this is an 8-CPU SMP box): +it to CPU4-7 (this is an 8-CPU SMP box): +[root@moon 44]# cd /proc/irq/44 [root@moon 44]# cat smp_affinity ffffffff + [root@moon 44]# echo 0f > smp_affinity [root@moon 44]# cat smp_affinity 0000000f @@ -21,17 +30,27 @@ PING hell (195.4.7.3): 56 data bytes --- hell ping statistics --- 6029 packets transmitted, 6027 packets received, 0% packet loss round-trip min/avg/max = 0.1/0.1/0.4 ms -[root@moon 44]# cat /proc/interrupts | grep 44: - 44: 0 1785 1785 1783 1783 1 -1 0 IO-APIC-level eth1 +[root@moon 44]# cat /proc/interrupts | grep 'CPU\|44:' + CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7 + 44: 1068 1785 1785 1783 0 0 0 0 IO-APIC-level eth1 + +As can be seen from the line above IRQ44 was delivered only to the first four +processors (0-3). +Now lets restrict that IRQ to CPU(4-7). + [root@moon 44]# echo f0 > smp_affinity +[root@moon 44]# cat smp_affinity +000000f0 [root@moon 44]# ping -f h PING hell (195.4.7.3): 56 data bytes .. --- hell ping statistics --- 2779 packets transmitted, 2777 packets received, 0% packet loss round-trip min/avg/max = 0.1/0.5/585.4 ms -[root@moon 44]# cat /proc/interrupts | grep 44: - 44: 1068 1785 1785 1784 1784 1069 1070 1069 IO-APIC-level eth1 -[root@moon 44]# +[root@moon 44]# cat /proc/interrupts | 'CPU\|44:' + CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7 + 44: 1068 1785 1785 1783 1784 1069 1070 1069 IO-APIC-level eth1 + +This time around IRQ44 was delivered only to the last four processors. +i.e counters for the CPU0-3 did not change. diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index dbc3c6a3650f..7f268f327d75 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -380,28 +380,35 @@ i386 and x86_64 platforms support the new IRQ vector displays. Of some interest is the introduction of the /proc/irq directory to 2.4. It could be used to set IRQ to CPU affinity, this means that you can "hook" an IRQ to only one CPU, or to exclude a CPU of handling IRQs. The contents of the -irq subdir is one subdir for each IRQ, and one file; prof_cpu_mask +irq subdir is one subdir for each IRQ, and two files; default_smp_affinity and +prof_cpu_mask. For example > ls /proc/irq/ 0 10 12 14 16 18 2 4 6 8 prof_cpu_mask - 1 11 13 15 17 19 3 5 7 9 + 1 11 13 15 17 19 3 5 7 9 default_smp_affinity > ls /proc/irq/0/ smp_affinity -The contents of the prof_cpu_mask file and each smp_affinity file for each IRQ -is the same by default: +smp_affinity is a bitmask, in which you can specify which CPUs can handle the +IRQ, you can set it by doing: - > cat /proc/irq/0/smp_affinity - ffffffff + > echo 1 > /proc/irq/10/smp_affinity + +This means that only the first CPU will handle the IRQ, but you can also echo +5 which means that only the first and fourth CPU can handle the IRQ. -It's a bitmask, in which you can specify which CPUs can handle the IRQ, you can -set it by doing: +The contents of each smp_affinity file is the same by default: + + > cat /proc/irq/0/smp_affinity + ffffffff - > echo 1 > /proc/irq/prof_cpu_mask +The default_smp_affinity mask applies to all non-active IRQs, which are the +IRQs which have not yet been allocated/activated, and hence which lack a +/proc/irq/[0-9]* directory. -This means that only the first CPU will handle the IRQ, but you can also echo 5 -which means that only the first and fourth CPU can handle the IRQ. +prof_cpu_mask specifies which CPUs are to be profiled by the system wide +profiler. Default value is ffffffff (all cpus). The way IRQs are routed is handled by the IO-APIC, and it's Round Robin between all the CPUs which are allowed to handle it. As usual the kernel has -- cgit v1.2.3 From e29c98d12b3f02d6ac711c60b4a5f8a46d1cf19b Mon Sep 17 00:00:00 2001 From: Gautham R Shenoy Date: Thu, 29 May 2008 12:36:18 +0530 Subject: sched: update the sched-domains debug documentation SCHED_DOMAIN_DEBUG mentioned in the Documentation for sched-domains for enabling sched-domains debugging doesn't exist anymore. Update the documentation to reflect the correct way of enabling sched-domain debugging. Signed-off-by: Gautham R Shenoy Signed-off-by: Ingo Molnar --- Documentation/scheduler/sched-domains.txt | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) (limited to 'Documentation') diff --git a/Documentation/scheduler/sched-domains.txt b/Documentation/scheduler/sched-domains.txt index a9e990ab980f..373ceacc367e 100644 --- a/Documentation/scheduler/sched-domains.txt +++ b/Documentation/scheduler/sched-domains.txt @@ -61,10 +61,7 @@ builder by #define'ing ARCH_HASH_SCHED_DOMAIN, and exporting your arch_init_sched_domains function. This function will attach domains to all CPUs using cpu_attach_domain. -Implementors should change the line -#undef SCHED_DOMAIN_DEBUG -to -#define SCHED_DOMAIN_DEBUG -in kernel/sched.c as this enables an error checking parse of the sched domains +The sched-domains debugging infrastructure can be enabled by enabling +CONFIG_SCHED_DEBUG. This enables an error checking parse of the sched domains which should catch most possible errors (described above). It also prints out the domain structure in a visual format. -- cgit v1.2.3 From c50cbb05a05cf1f9ca3592272eff053c847727d8 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Wed, 4 Jun 2008 21:47:29 -0700 Subject: cpu topology: always define CPU topology information This can result in an empty topology directory in sysfs, and requires in-kernel users to protect all uses with #ifdef - see . The documentation of CPU topology specifies what the defaults should be if only partial information is available from the hardware. So we can provide these defaults as a fallback. This patch: - Adds default definitions of the 4 topology macros to - Changes drivers/base/topology.c to use the topology macros unconditionally and to cope with definitions that aren't lvalues - Updates documentation accordingly [ From: Andrew Morton - fold now-duplicated code - fix layout ] Signed-off-by: Ben Hutchings Cc: Vegard Nossum Cc: Nick Piggin Cc: Chandra Seetharaman Cc: Suresh Siddha Cc: Mike Travis Cc: Christoph Lameter Cc: John Hawkes Cc: Zhang, Yanmin Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar --- Documentation/cputopology.txt | 26 +++++++++----------------- 1 file changed, 9 insertions(+), 17 deletions(-) (limited to 'Documentation') diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt index b61cb9564023..bd699da24666 100644 --- a/Documentation/cputopology.txt +++ b/Documentation/cputopology.txt @@ -14,9 +14,8 @@ represent the thread siblings to cpu X in the same physical package; To implement it in an architecture-neutral way, a new source file, drivers/base/topology.c, is to export the 4 attributes. -If one architecture wants to support this feature, it just needs to -implement 4 defines, typically in file include/asm-XXX/topology.h. -The 4 defines are: +For an architecture to support this feature, it must define some of +these macros in include/asm-XXX/topology.h: #define topology_physical_package_id(cpu) #define topology_core_id(cpu) #define topology_thread_siblings(cpu) @@ -25,17 +24,10 @@ The 4 defines are: The type of **_id is int. The type of siblings is cpumask_t. -To be consistent on all architectures, the 4 attributes should have -default values if their values are unavailable. Below is the rule. -1) physical_package_id: If cpu has no physical package id, -1 is the -default value. -2) core_id: If cpu doesn't support multi-core, its core id is 0. -3) thread_siblings: Just include itself, if the cpu doesn't support -HT/multi-thread. -4) core_siblings: Just include itself, if the cpu doesn't support -multi-core and HT/Multi-thread. - -So be careful when declaring the 4 defines in include/asm-XXX/topology.h. - -If an attribute isn't defined on an architecture, it won't be exported. - +To be consistent on all architectures, include/linux/topology.h +provides default definitions for any of the above macros that are +not defined by include/asm-XXX/topology.h: +1) physical_package_id: -1 +2) core_id: 0 +3) thread_siblings: just the given CPU +4) core_siblings: just the given CPU -- cgit v1.2.3 From d2e1c97331d37a477ef7e9a272b4de4e53b893be Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 10 Jun 2008 17:53:34 +0200 Subject: ALSA: hda - remove position_fix=3 position_fix=3 is the option to correct the DMA position with the FIFO size. But, it never worked correctly, and we have now more other workarounds for the DMA position fixes. Thus better to remove it. Also, change POS_FIX_NONE to POS_FIX_LPIB to represent its real role better. Signed-off-by: Takashi Iwai Signed-off-by: Jaroslav Kysela --- Documentation/sound/alsa/ALSA-Configuration.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt index 529073dea196..ab28f7b62f29 100644 --- a/Documentation/sound/alsa/ALSA-Configuration.txt +++ b/Documentation/sound/alsa/ALSA-Configuration.txt @@ -753,7 +753,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. [Multiple options for each card instance] model - force the model name - position_fix - Fix DMA pointer (0 = auto, 1 = none, 2 = POSBUF, 3 = FIFO size) + position_fix - Fix DMA pointer (0 = auto, 1 = use LPIB, 2 = POSBUF) probe_mask - Bitmask to probe codecs (default = -1, meaning all slots) [Single (global) options] -- cgit v1.2.3 From 8c53b96f229aa6e27f17855cbbf8e4243868a3a9 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 10 Jun 2008 17:53:35 +0200 Subject: ALSA: hda - Add description of bdl_pos_adj option Added a brief description of the new bdl_pos_adj option to ALSA-Configuration.txt. Signed-off-by: Takashi Iwai Signed-off-by: Jaroslav Kysela --- Documentation/sound/alsa/ALSA-Configuration.txt | 3 +++ 1 file changed, 3 insertions(+) (limited to 'Documentation') diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt index ab28f7b62f29..72aff61e7315 100644 --- a/Documentation/sound/alsa/ALSA-Configuration.txt +++ b/Documentation/sound/alsa/ALSA-Configuration.txt @@ -755,6 +755,9 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. model - force the model name position_fix - Fix DMA pointer (0 = auto, 1 = use LPIB, 2 = POSBUF) probe_mask - Bitmask to probe codecs (default = -1, meaning all slots) + bdl_pos_adj - Specifies the DMA IRQ timing delay in samples. + Passing -1 will make the driver to choose the appropriate + value based on the controller chip. [Single (global) options] single_cmd - Use single immediate commands to communicate with -- cgit v1.2.3 From f7d62364b2cef85cbcd4feffdd3632ef7c3b61c2 Mon Sep 17 00:00:00 2001 From: Hiroshi Shimamoto Date: Tue, 10 Jun 2008 20:29:19 -0700 Subject: sched: fix typo in Documentation/scheduler/sched-rt-group.txt Fix minor typos. Signed-off-by: Hiroshi Shimamoto Signed-off-by: Ingo Molnar --- Documentation/scheduler/sched-rt-group.txt | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/scheduler/sched-rt-group.txt b/Documentation/scheduler/sched-rt-group.txt index 14f901f639ee..3ef339f491e0 100644 --- a/Documentation/scheduler/sched-rt-group.txt +++ b/Documentation/scheduler/sched-rt-group.txt @@ -51,9 +51,9 @@ needs only about 3% CPU time to do so, it can do with a 0.03 * 0.005s = 0.00015s. So this group can be scheduled with a period of 0.005s and a run time of 0.00015s. -The remaining CPU time will be used for user input and other tass. Because +The remaining CPU time will be used for user input and other tasks. Because realtime tasks have explicitly allocated the CPU time they need to perform -their tasks, buffer underruns in the graphocs or audio can be eliminated. +their tasks, buffer underruns in the graphics or audio can be eliminated. NOTE: the above example is not fully implemented as of yet (2.6.25). We still lack an EDF scheduler to make non-uniform periods usable. -- cgit v1.2.3 From 16d752397301b95abaa95cbaf9e785d221872311 Mon Sep 17 00:00:00 2001 From: Rene Herman Date: Tue, 24 Jun 2008 19:38:56 +0200 Subject: thermal: Create CONFIG_THERMAL_HWMON=n A bug in libsensors <= 2.10.6 is exposed when this new hwmon I/F is enabled. Create CONFIG_THERMAL_HWMON=n until some time after libsensors 2.10.7 ships so those users can run the latest kernel. libsensors 3.x is already fixed -- those users can use CONFIG_THERMAL_HWMON=y now. Signed-off-by: Rene Herman Acked-by: Mark M. Hoffman Signed-off-by: Len Brown --- Documentation/feature-removal-schedule.txt | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'Documentation') diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 5b3f31faed56..46ece3fba6f9 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -312,3 +312,12 @@ When: 2.6.26 Why: Implementation became generic; users should now include linux/semaphore.h instead. Who: Matthew Wilcox + +--------------------------- + +What: CONFIG_THERMAL_HWMON +When: January 2009 +Why: This option was introduced just to allow older lm-sensors userspace + to keep working over the upgrade to 2.6.26. At the scheduled time of + removal fixed lm-sensors (2.x or 3.x) should be readily available. +Who: Rene Herman -- cgit v1.2.3 From 104fe9a2d2a56f25fb95800a7ab0f7600dd6879c Mon Sep 17 00:00:00 2001 From: Michael Krufky Date: Fri, 13 Jun 2008 03:29:43 -0300 Subject: V4L/DVB (8043): au0828: add support for additional USB device id's Signed-off-by: Michael Krufky Signed-off-by: Mauro Carvalho Chehab --- Documentation/video4linux/CARDLIST.au0828 | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/video4linux/CARDLIST.au0828 b/Documentation/video4linux/CARDLIST.au0828 index aaae360312e4..86d1c8e7b18f 100644 --- a/Documentation/video4linux/CARDLIST.au0828 +++ b/Documentation/video4linux/CARDLIST.au0828 @@ -1,4 +1,4 @@ 0 -> Unknown board (au0828) - 1 -> Hauppauge HVR950Q (au0828) [2040:7200] + 1 -> Hauppauge HVR950Q (au0828) [2040:7200,2040:7210,2040:7217,2040:721b,2040:721f,2040:7280,0fd9:0008] 2 -> Hauppauge HVR850 (au0828) [2040:7240] 3 -> DViCO FusionHDTV USB (au0828) [0fe9:d620] -- cgit v1.2.3 From f471f92339860c35b561cf45ad563ab1ff07c386 Mon Sep 17 00:00:00 2001 From: Michal Schmidt Date: Thu, 26 Jun 2008 16:06:19 +0200 Subject: s2io: fix documentation about intr_type The documentation for intr_type module parameter of the s2io driver is not consistent with the code. The comments in drivers/net/s2io.c are OK, but Documentation/networking/s2io.txt is wrong. Pointed out by Andrew Hecox. Signed-off-by: Michal Schmidt Signed-off-by: Jeff Garzik --- Documentation/networking/s2io.txt | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/networking/s2io.txt b/Documentation/networking/s2io.txt index 4bde53e85f3f..1e28e2ddb90a 100644 --- a/Documentation/networking/s2io.txt +++ b/Documentation/networking/s2io.txt @@ -83,9 +83,9 @@ Valid range: Limited by memory on system Default: 30 e. intr_type -Specifies interrupt type. Possible values 1(INTA), 2(MSI), 3(MSI-X) -Valid range: 1-3 -Default: 1 +Specifies interrupt type. Possible values 0(INTA), 2(MSI-X) +Valid values: 0, 2 +Default: 2 5. Performance suggestions General: -- cgit v1.2.3 From 54b4cbd26987f84791d6e05863a715ded9f7b3a5 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Thu, 26 Jun 2008 21:28:10 +0200 Subject: x86, AMD IOMMU: add documentation for kernel parameters Add documentation for the kernel parameters introduced with this driver. Signed-off-by: Joerg Roedel Cc: iommu@lists.linux-foundation.org Cc: bhavna.sarathy@amd.com Cc: Sebastian.Biemueller@amd.com Cc: robert.richter@amd.com Cc: joro@8bytes.org Signed-off-by: Ingo Molnar --- Documentation/kernel-parameters.txt | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index e07c432c731f..fc8f93606ec1 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -271,6 +271,18 @@ and is between 256 and 4096 characters. It is defined in the file aic79xx= [HW,SCSI] See Documentation/scsi/aic79xx.txt. + amd_iommu= [HW,X86-84] + Pass parameters to the AMD IOMMU driver in the system. + Possible values are: + off - disable the driver for AMD IOMMU + isolate - enable device isolation (each device, as far + as possible, will get its own protection + domain) + amd_iommu_size= [HW,X86-64] + Define the size of the aperture for the AMD IOMMU + driver. Possible values are: + '32M', '64M' (default), '128M', '256M', '512M', '1G' + amijoy.map= [HW,JOY] Amiga joystick support Map of devices attached to JOY0DAT and JOY1DAT Format: , -- cgit v1.2.3 From 9f1585cb03866452e0df61a83c88302181e50054 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Thu, 26 Jun 2008 08:25:57 +0100 Subject: [GFS2] Glock documentation This patch adds a file describing the internals of GFS2's glock abstraction. Signed-off-by: Steven Whitehouse --- Documentation/filesystems/gfs2-glocks.txt | 114 ++++++++++++++++++++++++++++++ 1 file changed, 114 insertions(+) create mode 100644 Documentation/filesystems/gfs2-glocks.txt (limited to 'Documentation') diff --git a/Documentation/filesystems/gfs2-glocks.txt b/Documentation/filesystems/gfs2-glocks.txt new file mode 100644 index 000000000000..4dae9a3840bf --- /dev/null +++ b/Documentation/filesystems/gfs2-glocks.txt @@ -0,0 +1,114 @@ + Glock internal locking rules + ------------------------------ + +This documents the basic principles of the glock state machine +internals. Each glock (struct gfs2_glock in fs/gfs2/incore.h) +has two main (internal) locks: + + 1. A spinlock (gl_spin) which protects the internal state such + as gl_state, gl_target and the list of holders (gl_holders) + 2. A non-blocking bit lock, GLF_LOCK, which is used to prevent other + threads from making calls to the DLM, etc. at the same time. If a + thread takes this lock, it must then call run_queue (usually via the + workqueue) when it releases it in order to ensure any pending tasks + are completed. + +The gl_holders list contains all the queued lock requests (not +just the holders) associated with the glock. If there are any +held locks, then they will be contiguous entries at the head +of the list. Locks are granted in strictly the order that they +are queued, except for those marked LM_FLAG_PRIORITY which are +used only during recovery, and even then only for journal locks. + +There are three lock states that users of the glock layer can request, +namely shared (SH), deferred (DF) and exclusive (EX). Those translate +to the following DLM lock modes: + +Glock mode | DLM lock mode +------------------------------ + UN | IV/NL Unlocked (no DLM lock associated with glock) or NL + SH | PR (Protected read) + DF | CW (Concurrent write) + EX | EX (Exclusive) + +Thus DF is basically a shared mode which is incompatible with the "normal" +shared lock mode, SH. In GFS2 the DF mode is used exclusively for direct I/O +operations. The glocks are basically a lock plus some routines which deal +with cache management. The following rules apply for the cache: + +Glock mode | Cache data | Cache Metadata | Dirty Data | Dirty Metadata +-------------------------------------------------------------------------- + UN | No | No | No | No + SH | Yes | Yes | No | No + DF | No | Yes | No | No + EX | Yes | Yes | Yes | Yes + +These rules are implemented using the various glock operations which +are defined for each type of glock. Not all types of glocks use +all the modes. Only inode glocks use the DF mode for example. + +Table of glock operations and per type constants: + +Field | Purpose +---------------------------------------------------------------------------- +go_xmote_th | Called before remote state change (e.g. to sync dirty data) +go_xmote_bh | Called after remote state change (e.g. to refill cache) +go_inval | Called if remote state change requires invalidating the cache +go_demote_ok | Returns boolean value of whether its ok to demote a glock + | (e.g. checks timeout, and that there is no cached data) +go_lock | Called for the first local holder of a lock +go_unlock | Called on the final local unlock of a lock +go_dump | Called to print content of object for debugfs file, or on + | error to dump glock to the log. +go_type; | The type of the glock, LM_TYPE_..... +go_min_hold_time | The minimum hold time + +The minimum hold time for each lock is the time after a remote lock +grant for which we ignore remote demote requests. This is in order to +prevent a situation where locks are being bounced around the cluster +from node to node with none of the nodes making any progress. This +tends to show up most with shared mmaped files which are being written +to by multiple nodes. By delaying the demotion in response to a +remote callback, that gives the userspace program time to make +some progress before the pages are unmapped. + +There is a plan to try and remove the go_lock and go_unlock callbacks +if possible, in order to try and speed up the fast path though the locking. +Also, eventually we hope to make the glock "EX" mode locally shared +such that any local locking will be done with the i_mutex as required +rather than via the glock. + +Locking rules for glock operations: + +Operation | GLF_LOCK bit lock held | gl_spin spinlock held +----------------------------------------------------------------- +go_xmote_th | Yes | No +go_xmote_bh | Yes | No +go_inval | Yes | No +go_demote_ok | Sometimes | Yes +go_lock | Yes | No +go_unlock | Yes | No +go_dump | Sometimes | Yes + +N.B. Operations must not drop either the bit lock or the spinlock +if its held on entry. go_dump and do_demote_ok must never block. +Note that go_dump will only be called if the glock's state +indicates that it is caching uptodate data. + +Glock locking order within GFS2: + + 1. i_mutex (if required) + 2. Rename glock (for rename only) + 3. Inode glock(s) + (Parents before children, inodes at "same level" with same parent in + lock number order) + 4. Rgrp glock(s) (for (de)allocation operations) + 5. Transaction glock (via gfs2_trans_begin) for non-read operations + 6. Page lock (always last, very important!) + +There are two glocks per inode. One deals with access to the inode +itself (locking order as above), and the other, known as the iopen +glock is used in conjunction with the i_nlink field in the inode to +determine the lifetime of the inode in question. Locking of inodes +is on a per-inode basis. Locking of rgrps is on a per rgrp basis. + -- cgit v1.2.3 From 2260e63a2f313f416b31af80d02f02ef92d20d78 Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Tue, 1 Jul 2008 22:38:18 +0200 Subject: i2c: Documentation: fix device matching description The matching process described for new style clients in Documentation/i2c/writing-clients is classed as out-of-date as it requires the presence of an .id_table entry in the driver's i2c_driver entry. Signed-off-by: Ben Dooks Signed-off-by: Jean Delvare --- Documentation/i2c/writing-clients | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients index ee75cbace28d..d4cd4126d1ad 100644 --- a/Documentation/i2c/writing-clients +++ b/Documentation/i2c/writing-clients @@ -25,12 +25,23 @@ routines, and should be zero-initialized except for fields with data you provide. A client structure holds device-specific information like the driver model device node, and its I2C address. +/* iff driver uses driver model ("new style") binding model: */ + +static struct i2c_device_id foo_idtable[] = { + { "foo", my_id_for_foo }, + { "bar", my_id_for_bar }, + { } +}; + +MODULE_DEVICE_TABLE(i2c, foo_idtable); + static struct i2c_driver foo_driver = { .driver = { .name = "foo", }, /* iff driver uses driver model ("new style") binding model: */ + .id_table = foo_ids, .probe = foo_probe, .remove = foo_remove, @@ -173,10 +184,9 @@ handle may be used during foo_probe(). If foo_probe() reports success (zero not a negative status code) it may save the handle and use it until foo_remove() returns. That binding model is used by most Linux drivers. -Drivers match devices when i2c_client.driver_name and the driver name are -the same; this approach is used in several other busses that don't have -device typing support in the hardware. The driver and module name should -match, so hotplug/coldplug mechanisms will modprobe the driver. +The probe function is called when an entry in the id_table name field +matches the device's name. It is passed the entry that was matched so +the driver knows which one in the table matched. Device Creation (Standard driver model) -- cgit v1.2.3 From 77a538d5aa25a8866606a1faa4300c9aa2a59dfc Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Tue, 1 Jul 2008 17:22:48 -0700 Subject: ipv4: fix sysctl documentation of time related values These sysctl values are time related and all use the same routine (proc_dointvec_jiffies) that internally converts from seconds to jiffies. The code is fine, the documentation is just wrong. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.txt | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) (limited to 'Documentation') diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 17a6e46fbd43..17f1f91af35c 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -81,23 +81,23 @@ inet_peer_minttl - INTEGER Minimum time-to-live of entries. Should be enough to cover fragment time-to-live on the reassembling side. This minimum time-to-live is guaranteed if the pool size is less than inet_peer_threshold. - Measured in jiffies(1). + Measured in seconds. inet_peer_maxttl - INTEGER Maximum time-to-live of entries. Unused entries will expire after this period of time if there is no memory pressure on the pool (i.e. when the number of entries in the pool is very small). - Measured in jiffies(1). + Measured in seconds. inet_peer_gc_mintime - INTEGER Minimum interval between garbage collection passes. This interval is in effect under high memory pressure on the pool. - Measured in jiffies(1). + Measured in seconds. inet_peer_gc_maxtime - INTEGER Minimum interval between garbage collection passes. This interval is in effect under low (or absent) memory pressure on the pool. - Measured in jiffies(1). + Measured in seconds. TCP variables: @@ -794,10 +794,6 @@ tag - INTEGER Allows you to write a number, which can be used as required. Default value is 0. -(1) Jiffie: internal timeunit for the kernel. On the i386 1/100s, on the -Alpha 1/1024s. See the HZ define in /usr/include/asm/param.h for the exact -value on your system. - Alexey Kuznetsov. kuznet@ms2.inr.ac.ru -- cgit v1.2.3 From c1c72b59941e2f5aad4b02609d7ee7b121734b8d Mon Sep 17 00:00:00 2001 From: "Martin K. Petersen" Date: Tue, 17 Jun 2008 18:59:57 +0200 Subject: block: Data integrity infrastructure documentation Signed-off-by: Martin K. Petersen Signed-off-by: Jens Axboe --- Documentation/ABI/testing/sysfs-block | 34 ++++ Documentation/block/data-integrity.txt | 327 +++++++++++++++++++++++++++++++++ 2 files changed, 361 insertions(+) create mode 100644 Documentation/block/data-integrity.txt (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block index 4bd9ea539129..44f52a4f5903 100644 --- a/Documentation/ABI/testing/sysfs-block +++ b/Documentation/ABI/testing/sysfs-block @@ -26,3 +26,37 @@ Description: I/O statistics of partition . The format is the same as the above-written /sys/block//stat format. + + +What: /sys/block//integrity/format +Date: June 2008 +Contact: Martin K. Petersen +Description: + Metadata format for integrity capable block device. + E.g. T10-DIF-TYPE1-CRC. + + +What: /sys/block//integrity/read_verify +Date: June 2008 +Contact: Martin K. Petersen +Description: + Indicates whether the block layer should verify the + integrity of read requests serviced by devices that + support sending integrity metadata. + + +What: /sys/block//integrity/tag_size +Date: June 2008 +Contact: Martin K. Petersen +Description: + Number of bytes of integrity tag space available per + 512 bytes of data. + + +What: /sys/block//integrity/write_generate +Date: June 2008 +Contact: Martin K. Petersen +Description: + Indicates whether the block layer should automatically + generate checksums for write requests bound for + devices that support receiving integrity metadata. diff --git a/Documentation/block/data-integrity.txt b/Documentation/block/data-integrity.txt new file mode 100644 index 000000000000..e9dc8d86adc7 --- /dev/null +++ b/Documentation/block/data-integrity.txt @@ -0,0 +1,327 @@ +---------------------------------------------------------------------- +1. INTRODUCTION + +Modern filesystems feature checksumming of data and metadata to +protect against data corruption. However, the detection of the +corruption is done at read time which could potentially be months +after the data was written. At that point the original data that the +application tried to write is most likely lost. + +The solution is to ensure that the disk is actually storing what the +application meant it to. Recent additions to both the SCSI family +protocols (SBC Data Integrity Field, SCC protection proposal) as well +as SATA/T13 (External Path Protection) try to remedy this by adding +support for appending integrity metadata to an I/O. The integrity +metadata (or protection information in SCSI terminology) includes a +checksum for each sector as well as an incrementing counter that +ensures the individual sectors are written in the right order. And +for some protection schemes also that the I/O is written to the right +place on disk. + +Current storage controllers and devices implement various protective +measures, for instance checksumming and scrubbing. But these +technologies are working in their own isolated domains or at best +between adjacent nodes in the I/O path. The interesting thing about +DIF and the other integrity extensions is that the protection format +is well defined and every node in the I/O path can verify the +integrity of the I/O and reject it if corruption is detected. This +allows not only corruption prevention but also isolation of the point +of failure. + +---------------------------------------------------------------------- +2. THE DATA INTEGRITY EXTENSIONS + +As written, the protocol extensions only protect the path between +controller and storage device. However, many controllers actually +allow the operating system to interact with the integrity metadata +(IMD). We have been working with several FC/SAS HBA vendors to enable +the protection information to be transferred to and from their +controllers. + +The SCSI Data Integrity Field works by appending 8 bytes of protection +information to each sector. The data + integrity metadata is stored +in 520 byte sectors on disk. Data + IMD are interleaved when +transferred between the controller and target. The T13 proposal is +similar. + +Because it is highly inconvenient for operating systems to deal with +520 (and 4104) byte sectors, we approached several HBA vendors and +encouraged them to allow separation of the data and integrity metadata +scatter-gather lists. + +The controller will interleave the buffers on write and split them on +read. This means that the Linux can DMA the data buffers to and from +host memory without changes to the page cache. + +Also, the 16-bit CRC checksum mandated by both the SCSI and SATA specs +is somewhat heavy to compute in software. Benchmarks found that +calculating this checksum had a significant impact on system +performance for a number of workloads. Some controllers allow a +lighter-weight checksum to be used when interfacing with the operating +system. Emulex, for instance, supports the TCP/IP checksum instead. +The IP checksum received from the OS is converted to the 16-bit CRC +when writing and vice versa. This allows the integrity metadata to be +generated by Linux or the application at very low cost (comparable to +software RAID5). + +The IP checksum is weaker than the CRC in terms of detecting bit +errors. However, the strength is really in the separation of the data +buffers and the integrity metadata. These two distinct buffers much +match up for an I/O to complete. + +The separation of the data and integrity metadata buffers as well as +the choice in checksums is referred to as the Data Integrity +Extensions. As these extensions are outside the scope of the protocol +bodies (T10, T13), Oracle and its partners are trying to standardize +them within the Storage Networking Industry Association. + +---------------------------------------------------------------------- +3. KERNEL CHANGES + +The data integrity framework in Linux enables protection information +to be pinned to I/Os and sent to/received from controllers that +support it. + +The advantage to the integrity extensions in SCSI and SATA is that +they enable us to protect the entire path from application to storage +device. However, at the same time this is also the biggest +disadvantage. It means that the protection information must be in a +format that can be understood by the disk. + +Generally Linux/POSIX applications are agnostic to the intricacies of +the storage devices they are accessing. The virtual filesystem switch +and the block layer make things like hardware sector size and +transport protocols completely transparent to the application. + +However, this level of detail is required when preparing the +protection information to send to a disk. Consequently, the very +concept of an end-to-end protection scheme is a layering violation. +It is completely unreasonable for an application to be aware whether +it is accessing a SCSI or SATA disk. + +The data integrity support implemented in Linux attempts to hide this +from the application. As far as the application (and to some extent +the kernel) is concerned, the integrity metadata is opaque information +that's attached to the I/O. + +The current implementation allows the block layer to automatically +generate the protection information for any I/O. Eventually the +intent is to move the integrity metadata calculation to userspace for +user data. Metadata and other I/O that originates within the kernel +will still use the automatic generation interface. + +Some storage devices allow each hardware sector to be tagged with a +16-bit value. The owner of this tag space is the owner of the block +device. I.e. the filesystem in most cases. The filesystem can use +this extra space to tag sectors as they see fit. Because the tag +space is limited, the block interface allows tagging bigger chunks by +way of interleaving. This way, 8*16 bits of information can be +attached to a typical 4KB filesystem block. + +This also means that applications such as fsck and mkfs will need +access to manipulate the tags from user space. A passthrough +interface for this is being worked on. + + +---------------------------------------------------------------------- +4. BLOCK LAYER IMPLEMENTATION DETAILS + +4.1 BIO + +The data integrity patches add a new field to struct bio when +CONFIG_BLK_DEV_INTEGRITY is enabled. bio->bi_integrity is a pointer +to a struct bip which contains the bio integrity payload. Essentially +a bip is a trimmed down struct bio which holds a bio_vec containing +the integrity metadata and the required housekeeping information (bvec +pool, vector count, etc.) + +A kernel subsystem can enable data integrity protection on a bio by +calling bio_integrity_alloc(bio). This will allocate and attach the +bip to the bio. + +Individual pages containing integrity metadata can subsequently be +attached using bio_integrity_add_page(). + +bio_free() will automatically free the bip. + + +4.2 BLOCK DEVICE + +Because the format of the protection data is tied to the physical +disk, each block device has been extended with a block integrity +profile (struct blk_integrity). This optional profile is registered +with the block layer using blk_integrity_register(). + +The profile contains callback functions for generating and verifying +the protection data, as well as getting and setting application tags. +The profile also contains a few constants to aid in completing, +merging and splitting the integrity metadata. + +Layered block devices will need to pick a profile that's appropriate +for all subdevices. blk_integrity_compare() can help with that. DM +and MD linear, RAID0 and RAID1 are currently supported. RAID4/5/6 +will require extra work due to the application tag. + + +---------------------------------------------------------------------- +5.0 BLOCK LAYER INTEGRITY API + +5.1 NORMAL FILESYSTEM + + The normal filesystem is unaware that the underlying block device + is capable of sending/receiving integrity metadata. The IMD will + be automatically generated by the block layer at submit_bio() time + in case of a WRITE. A READ request will cause the I/O integrity + to be verified upon completion. + + IMD generation and verification can be toggled using the + + /sys/block//integrity/write_generate + + and + + /sys/block//integrity/read_verify + + flags. + + +5.2 INTEGRITY-AWARE FILESYSTEM + + A filesystem that is integrity-aware can prepare I/Os with IMD + attached. It can also use the application tag space if this is + supported by the block device. + + + int bdev_integrity_enabled(block_device, int rw); + + bdev_integrity_enabled() will return 1 if the block device + supports integrity metadata transfer for the data direction + specified in 'rw'. + + bdev_integrity_enabled() honors the write_generate and + read_verify flags in sysfs and will respond accordingly. + + + int bio_integrity_prep(bio); + + To generate IMD for WRITE and to set up buffers for READ, the + filesystem must call bio_integrity_prep(bio). + + Prior to calling this function, the bio data direction and start + sector must be set, and the bio should have all data pages + added. It is up to the caller to ensure that the bio does not + change while I/O is in progress. + + bio_integrity_prep() should only be called if + bio_integrity_enabled() returned 1. + + + int bio_integrity_tag_size(bio); + + If the filesystem wants to use the application tag space it will + first have to find out how much storage space is available. + Because tag space is generally limited (usually 2 bytes per + sector regardless of sector size), the integrity framework + supports interleaving the information between the sectors in an + I/O. + + Filesystems can call bio_integrity_tag_size(bio) to find out how + many bytes of storage are available for that particular bio. + + Another option is bdev_get_tag_size(block_device) which will + return the number of available bytes per hardware sector. + + + int bio_integrity_set_tag(bio, void *tag_buf, len); + + After a successful return from bio_integrity_prep(), + bio_integrity_set_tag() can be used to attach an opaque tag + buffer to a bio. Obviously this only makes sense if the I/O is + a WRITE. + + + int bio_integrity_get_tag(bio, void *tag_buf, len); + + Similarly, at READ I/O completion time the filesystem can + retrieve the tag buffer using bio_integrity_get_tag(). + + +6.3 PASSING EXISTING INTEGRITY METADATA + + Filesystems that either generate their own integrity metadata or + are capable of transferring IMD from user space can use the + following calls: + + + struct bip * bio_integrity_alloc(bio, gfp_mask, nr_pages); + + Allocates the bio integrity payload and hangs it off of the bio. + nr_pages indicate how many pages of protection data need to be + stored in the integrity bio_vec list (similar to bio_alloc()). + + The integrity payload will be freed at bio_free() time. + + + int bio_integrity_add_page(bio, page, len, offset); + + Attaches a page containing integrity metadata to an existing + bio. The bio must have an existing bip, + i.e. bio_integrity_alloc() must have been called. For a WRITE, + the integrity metadata in the pages must be in a format + understood by the target device with the notable exception that + the sector numbers will be remapped as the request traverses the + I/O stack. This implies that the pages added using this call + will be modified during I/O! The first reference tag in the + integrity metadata must have a value of bip->bip_sector. + + Pages can be added using bio_integrity_add_page() as long as + there is room in the bip bio_vec array (nr_pages). + + Upon completion of a READ operation, the attached pages will + contain the integrity metadata received from the storage device. + It is up to the receiver to process them and verify data + integrity upon completion. + + +6.4 REGISTERING A BLOCK DEVICE AS CAPABLE OF EXCHANGING INTEGRITY + METADATA + + To enable integrity exchange on a block device the gendisk must be + registered as capable: + + int blk_integrity_register(gendisk, blk_integrity); + + The blk_integrity struct is a template and should contain the + following: + + static struct blk_integrity my_profile = { + .name = "STANDARDSBODY-TYPE-VARIANT-CSUM", + .generate_fn = my_generate_fn, + .verify_fn = my_verify_fn, + .get_tag_fn = my_get_tag_fn, + .set_tag_fn = my_set_tag_fn, + .tuple_size = sizeof(struct my_tuple_size), + .tag_size = , + }; + + 'name' is a text string which will be visible in sysfs. This is + part of the userland API so chose it carefully and never change + it. The format is standards body-type-variant. + E.g. T10-DIF-TYPE1-IP or T13-EPP-0-CRC. + + 'generate_fn' generates appropriate integrity metadata (for WRITE). + + 'verify_fn' verifies that the data buffer matches the integrity + metadata. + + 'tuple_size' must be set to match the size of the integrity + metadata per sector. I.e. 8 for DIF and EPP. + + 'tag_size' must be set to identify how many bytes of tag space + are available per hardware sector. For DIF this is either 2 or + 0 depending on the value of the Control Mode Page ATO bit. + + See 6.2 for a description of get_tag_fn and set_tag_fn. + +---------------------------------------------------------------------- +2007-12-24 Martin K. Petersen -- cgit v1.2.3 From 9db829f485c553a0e677a165b37f877bf74f36ff Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Thu, 3 Jul 2008 11:24:29 +0100 Subject: [ARM] JIVE: Initial machine support for Logitech Jive This is the base machine support for the Logitech Jive machine. Signed-off-by: Ben Dooks --- Documentation/kernel-parameters.txt | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index e07c432c731f..f1e970acad4c 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1208,6 +1208,11 @@ and is between 256 and 4096 characters. It is defined in the file mtdparts= [MTD] See drivers/mtd/cmdlinepart.c. + mtdset= [ARM] + ARM/S3C2412 JIVE boot control + + See arch/arm/mach-s3c2412/mach-jive.c + mtouchusb.raw_coordinates= [HW] Make the MicroTouch USB driver use raw coordinates ('y', default) or cooked coordinates ('n') -- cgit v1.2.3 From cde53535991fbb5c34a1566f25955297c1487b8d Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Fri, 4 Jul 2008 09:59:22 -0700 Subject: Christoph has moved Remove all clameter@sgi.com addresses from the kernel tree since they will become invalid on June 27th. Change my maintainer email address for the slab allocators to cl@linux-foundation.org (which will be the new email address for the future). Signed-off-by: Christoph Lameter Signed-off-by: Christoph Lameter Cc: Pekka Enberg Cc: Stephen Rothwell Cc: Matt Mackall Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/vm/slabinfo.c | 4 ++-- Documentation/vm/slub.txt | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/vm/slabinfo.c b/Documentation/vm/slabinfo.c index e4230ed16ee7..df3227605d59 100644 --- a/Documentation/vm/slabinfo.c +++ b/Documentation/vm/slabinfo.c @@ -1,7 +1,7 @@ /* * Slabinfo: Tool to get reports about slabs * - * (C) 2007 sgi, Christoph Lameter + * (C) 2007 sgi, Christoph Lameter * * Compile by: * @@ -99,7 +99,7 @@ void fatal(const char *x, ...) void usage(void) { - printf("slabinfo 5/7/2007. (c) 2007 sgi. clameter@sgi.com\n\n" + printf("slabinfo 5/7/2007. (c) 2007 sgi.\n\n" "slabinfo [-ahnpvtsz] [-d debugopts] [slab-regexp]\n" "-a|--aliases Show aliases\n" "-A|--activity Most active slabs first\n" diff --git a/Documentation/vm/slub.txt b/Documentation/vm/slub.txt index 7c13f22a0c9e..bb1f5c6e28b3 100644 --- a/Documentation/vm/slub.txt +++ b/Documentation/vm/slub.txt @@ -266,4 +266,4 @@ of other objects. slub_debug=FZ,dentry -Christoph Lameter, , May 30, 2007 +Christoph Lameter, May 30, 2007 -- cgit v1.2.3 From 450c622e9ff19888818d4e2c4d31adb97a5242b2 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Fri, 4 Jul 2008 09:59:33 -0700 Subject: Miguel Ojeda has moved Signed-off-by: Miguel Ojeda Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/auxdisplay/cfag12864b | 4 ++-- Documentation/auxdisplay/cfag12864b-example.c | 2 +- Documentation/auxdisplay/ks0108 | 4 ++-- 3 files changed, 5 insertions(+), 5 deletions(-) (limited to 'Documentation') diff --git a/Documentation/auxdisplay/cfag12864b b/Documentation/auxdisplay/cfag12864b index b714183d4125..eb7be393a510 100644 --- a/Documentation/auxdisplay/cfag12864b +++ b/Documentation/auxdisplay/cfag12864b @@ -3,7 +3,7 @@ =================================== License: GPLv2 -Author & Maintainer: Miguel Ojeda Sandonis +Author & Maintainer: Miguel Ojeda Sandonis Date: 2006-10-27 @@ -22,7 +22,7 @@ Date: 2006-10-27 1. DRIVER INFORMATION --------------------- -This driver support one cfag12864b display at time. +This driver supports a cfag12864b LCD. --------------------- diff --git a/Documentation/auxdisplay/cfag12864b-example.c b/Documentation/auxdisplay/cfag12864b-example.c index 7bfac354d4c9..2caeea5e4993 100644 --- a/Documentation/auxdisplay/cfag12864b-example.c +++ b/Documentation/auxdisplay/cfag12864b-example.c @@ -4,7 +4,7 @@ * Description: cfag12864b LCD userspace example program * License: GPLv2 * - * Author: Copyright (C) Miguel Ojeda Sandonis + * Author: Copyright (C) Miguel Ojeda Sandonis * Date: 2006-10-31 * * This program is free software; you can redistribute it and/or modify diff --git a/Documentation/auxdisplay/ks0108 b/Documentation/auxdisplay/ks0108 index 92b03b60c613..8ddda0c8ceef 100644 --- a/Documentation/auxdisplay/ks0108 +++ b/Documentation/auxdisplay/ks0108 @@ -3,7 +3,7 @@ ========================================== License: GPLv2 -Author & Maintainer: Miguel Ojeda Sandonis +Author & Maintainer: Miguel Ojeda Sandonis Date: 2006-10-27 @@ -21,7 +21,7 @@ Date: 2006-10-27 1. DRIVER INFORMATION --------------------- -This driver support the ks0108 LCD controller. +This driver supports the ks0108 LCD controller. --------------------- -- cgit v1.2.3 From f93f18cd94626108021c4e681f48d2d99bca5b90 Mon Sep 17 00:00:00 2001 From: Hiroshi Shimamoto Date: Fri, 4 Jul 2008 09:59:39 -0700 Subject: Update taskstats-struct document for scaled time accounting Update Documentation/accounting/taskstats-struct.txt for TASKSTATS_VERSION 6, adding scaled time accounting. Signed-off-by: Hiroshi Shimamoto Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/accounting/taskstats-struct.txt | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'Documentation') diff --git a/Documentation/accounting/taskstats-struct.txt b/Documentation/accounting/taskstats-struct.txt index 8aa7529f8258..cd784f46bf8a 100644 --- a/Documentation/accounting/taskstats-struct.txt +++ b/Documentation/accounting/taskstats-struct.txt @@ -24,6 +24,8 @@ There are three different groups of fields in the struct taskstats: 4) Per-task and per-thread context switch count statistics +5) Time accounting for SMT machines + Future extension should add fields to the end of the taskstats struct, and should not change the relative position of each field within the struct. @@ -164,4 +166,8 @@ struct taskstats { __u64 nvcsw; /* Context voluntary switch counter */ __u64 nivcsw; /* Context involuntary switch counter */ +5) Time accounting for SMT machines + __u64 ac_utimescaled; /* utime scaled on frequency etc */ + __u64 ac_stimescaled; /* stime scaled on frequency etc */ + __u64 cpu_scaled_run_real_total; /* scaled cpu_run_real_total */ } -- cgit v1.2.3 From 71f77055deeab9708c00717352bec05aa125c713 Mon Sep 17 00:00:00 2001 From: Pavel Machek Date: Fri, 4 Jul 2008 09:59:43 -0700 Subject: Doc*/kernel-parameters.txt: fix stale references Fix stale references to source files in kernel-parameters.txt. Signed-off-by: Pavel Machek Acked-by: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/kernel-parameters.txt | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index e07c432c731f..85c6f574e267 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -295,7 +295,7 @@ and is between 256 and 4096 characters. It is defined in the file when initialising the APIC and IO-APIC components. apm= [APM] Advanced Power Management - See header of arch/i386/kernel/apm.c. + See header of arch/x86/kernel/apm_32.c. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards Format: ,, @@ -638,7 +638,7 @@ and is between 256 and 4096 characters. It is defined in the file elanfreq= [X86-32] See comment before function elanfreq_setup() in - arch/i386/kernel/cpu/cpufreq/elanfreq.c. + arch/x86/kernel/cpu/cpufreq/elanfreq.c. elevator= [IOSCHED] Format: {"anticipatory" | "cfq" | "deadline" | "noop"} -- cgit v1.2.3 From bef67c5a7d3a9c45e091e36625c09c0c811e2672 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 4 Jul 2008 09:59:55 -0700 Subject: cgroups: document the effect of attaching PID 0 to a cgroup Document that a pid of zero(0) can be used to refer to the current task when attaching a task to a cgroup, as in the following usage: # echo 0 > /dev/cgroup/tasks This is consistent with existing cpuset behavior. Signed-off-by: Li Zefan Acked-by: Paul Jackson Acked-by: Dhaval Giani Cc: Paul Menage Cc: Balbir Singh Cc: Andrea Righi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/cgroups.txt | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'Documentation') diff --git a/Documentation/cgroups.txt b/Documentation/cgroups.txt index 824fc0274471..d9014aa0eb68 100644 --- a/Documentation/cgroups.txt +++ b/Documentation/cgroups.txt @@ -390,6 +390,10 @@ If you have several tasks to attach, you have to do it one after another: ... # /bin/echo PIDn > tasks +You can attach the current shell task by echoing 0: + +# echo 0 > tasks + 3. Kernel API ============= -- cgit v1.2.3 From 985ee7f224cca8a0d622b24ec399f364c63fc274 Mon Sep 17 00:00:00 2001 From: Paul Jackson Date: Fri, 4 Jul 2008 10:00:01 -0700 Subject: cpusets: document proc status cpus and mems allowed lists Provide a little documentation for the two new fields, Cpus_allowed_list and Mems_allowed_list, that were added to each /proc//status file a while back. Signed-off-by: Paul Jackson Acked-by: Michael Kerrisk Cc: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/cpusets.txt | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/cpusets.txt b/Documentation/cpusets.txt index 353504de3084..894b844153ea 100644 --- a/Documentation/cpusets.txt +++ b/Documentation/cpusets.txt @@ -154,13 +154,15 @@ browsing and modifying the cpusets presently known to the kernel. No new system calls are added for cpusets - all support for querying and modifying cpusets is via this cpuset file system. -The /proc//status file for each task has two added lines, +The /proc//status file for each task has four added lines, displaying the tasks cpus_allowed (on which CPUs it may be scheduled) and mems_allowed (on which Memory Nodes it may obtain memory), -in the format seen in the following example: +in the two formats seen in the following example: Cpus_allowed: ffffffff,ffffffff,ffffffff,ffffffff + Cpus_allowed_list: 0-127 Mems_allowed: ffffffff,ffffffff + Mems_allowed_list: 0-63 Each cpuset is represented by a directory in the cgroup file system containing (on top of the standard cgroup files) the following -- cgit v1.2.3 From d823f6bfec2844493c05961133895de21fa0e02d Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 4 Jul 2008 10:00:07 -0700 Subject: devcgroup: fix odd behaviour when writing 'a' to devices.allow # cat /devcg/devices.list a *:* rwm # echo a > devices.allow # cat /devcg/devices.list a *:* rwm a 0:0 rwm This is odd and maybe confusing. With this patch, writing 'a' to devices.allow will add 'a *:* rwm' to the whitelist. Also a few fixes and updates to the document. Signed-off-by: Li Zefan Cc: Pavel Emelyanov Cc: Serge E. Hallyn Cc: Paul Menage Cc: Balbir Singh Cc: James Morris Cc: Chris Wright Cc: Stephen Smalley Cc: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/controllers/devices.txt | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/controllers/devices.txt b/Documentation/controllers/devices.txt index 4dcea42432c2..7cc6e6a60672 100644 --- a/Documentation/controllers/devices.txt +++ b/Documentation/controllers/devices.txt @@ -13,7 +13,7 @@ either an integer or * for all. Access is a composition of r The root device cgroup starts with rwm to 'all'. A child device cgroup gets a copy of the parent. Administrators can then remove devices from the whitelist or add new entries. A child cgroup can -never receive a device access which is denied its parent. However +never receive a device access which is denied by its parent. However when a device access is removed from a parent it will not also be removed from the child(ren). @@ -29,7 +29,11 @@ allows cgroup 1 to read and mknod the device usually known as echo a > /cgroups/1/devices.deny -will remove the default 'a *:* mrw' entry. +will remove the default 'a *:* rwm' entry. Doing + + echo a > /cgroups/1/devices.allow + +will add the 'a *:* rwm' entry to the whitelist. 3. Security -- cgit v1.2.3 From 46b6d94eb04a718730c73b83db889341aad0515e Mon Sep 17 00:00:00 2001 From: Paul Jackson Date: Fri, 4 Jul 2008 10:00:09 -0700 Subject: doc: document the relax_domain_level kernel boot argument Document the kernel boot parameter: relax_domain_level=. Signed-off-by: Paul Jackson Cc: Michael Kerrisk Reviewed-by: Li Zefan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/cpusets.txt | 3 +++ Documentation/kernel-parameters.txt | 4 ++++ 2 files changed, 7 insertions(+) (limited to 'Documentation') diff --git a/Documentation/cpusets.txt b/Documentation/cpusets.txt index 894b844153ea..1f5a924d1e56 100644 --- a/Documentation/cpusets.txt +++ b/Documentation/cpusets.txt @@ -546,6 +546,9 @@ otherwise initial value -1 that indicates the cpuset has no request. ( 4 : search nodes in a chunk of node [on NUMA system] ) ( 5 : search system wide [on NUMA system] ) +The system default is architecture dependent. The system default +can be changed using the relax_domain_level= boot parameter. + This file is per-cpuset and affect the sched domain where the cpuset belongs to. Therefore if the flag 'sched_load_balance' of a cpuset is disabled, then 'sched_relax_domain_level' have no effect since diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 85c6f574e267..b52f47d588b4 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1679,6 +1679,10 @@ and is between 256 and 4096 characters. It is defined in the file Format: [,[,...]] See arch/*/kernel/reboot.c or arch/*/kernel/process.c + relax_domain_level= + [KNL, SMP] Set scheduler's default relax_domain_level. + See Documentation/cpusets.txt. + reserve= [KNL,BUGS] Force the kernel to ignore some iomem area reservetop= [X86-32] -- cgit v1.2.3 From 8b7fd21511f9b5016665814e03f7fc948bb64a98 Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Mon, 7 Jul 2008 16:40:26 +0900 Subject: x86: clean up amd_iommu documentation amd_iommu=off was replaced with a common parameter, iommu=off. Signed-off-by: FUJITA Tomonori Cc: joerg.roedel@amd.com Cc: iommu@lists.linux-foundation.org Cc: bhavna.sarathy@amd.com Cc: robert.richter@amd.com Cc: rjw@sisk.pl Signed-off-by: Ingo Molnar --- Documentation/kernel-parameters.txt | 1 - 1 file changed, 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index fc8f93606ec1..6b757b468bf1 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -274,7 +274,6 @@ and is between 256 and 4096 characters. It is defined in the file amd_iommu= [HW,X86-84] Pass parameters to the AMD IOMMU driver in the system. Possible values are: - off - disable the driver for AMD IOMMU isolate - enable device isolation (each device, as far as possible, will get its own protection domain) -- cgit v1.2.3 From 200001eb140ea33477965f2050bea0dac801974b Mon Sep 17 00:00:00 2001 From: Paul Jackson Date: Wed, 25 Jun 2008 05:44:46 -0700 Subject: x86 boot: only pick up additional EFI memmap if add_efi_memmap flag Applies on top of the previous patch: x86 boot: add code to add BIOS provided EFI memory entries to kernel Instead of always adding EFI memory map entries (if present) to the memory map after initially finding either E820 BIOS memory map entries and/or kernel command line memmap entries, -instead- only add such additional EFI memory map entries if the kernel boot option: add_efi_memmap is specified. Requiring this 'add_efi_memmap' option is backward compatible with kernels that didn't load such additional EFI memory map entries in the first place, and it doesn't override a configuration that tries to replace all E820 or EFI BIOS memory map entries with ones given entirely on the kernel command line. Signed-off-by: Paul Jackson Cc: "Yinghai Lu" Cc: "Jack Steiner" Cc: "Mike Travis" Cc: "Huang Cc: Ying" Cc: "Andi Kleen" Cc: "Andrew Morton" Cc: Paul Jackson Signed-off-by: Ingo Molnar --- Documentation/kernel-parameters.txt | 3 +++ Documentation/x86/x86_64/uefi.txt | 4 ++++ 2 files changed, 7 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index da13d6d1b2b0..795c487af8e4 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2150,6 +2150,9 @@ and is between 256 and 4096 characters. It is defined in the file usbhid.mousepoll= [USBHID] The interval which mice are to be polled at. + add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in + kernel's map of available physical RAM. + vdso= [X86-32,SH,x86-64] vdso=2: enable compat VDSO (default with COMPAT_VDSO) vdso=1: enable VDSO (default) diff --git a/Documentation/x86/x86_64/uefi.txt b/Documentation/x86/x86_64/uefi.txt index 7d77120a5184..a5e2b4fdb170 100644 --- a/Documentation/x86/x86_64/uefi.txt +++ b/Documentation/x86/x86_64/uefi.txt @@ -36,3 +36,7 @@ Mechanics: services. noefi turn off all EFI runtime services reboot_type=k turn off EFI reboot runtime service +- If the EFI memory map has additional entries not in the E820 map, + you can include those entries in the kernels memory map of available + physical RAM by using the following kernel command line parameter. + add_efi_memmap include EFI memory map of available physical RAM -- cgit v1.2.3 From afda335dc3872ca122842e26720ac6e6ef287aa2 Mon Sep 17 00:00:00 2001 From: Cyrill Gorcunov Date: Fri, 27 Jun 2008 19:43:40 +0400 Subject: x86: nmi_watchdog - documentation fix nmi_watchdog is set to NMI_NONE by default (ie disabled) on _any_ mode so lets fix documentation too. Signed-off-by: Cyrill Gorcunov Cc: "Maciej W. Rozycki" Signed-off-by: Ingo Molnar --- Documentation/nmi_watchdog.txt | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'Documentation') diff --git a/Documentation/nmi_watchdog.txt b/Documentation/nmi_watchdog.txt index 757c729ee42e..101bfcf19c0d 100644 --- a/Documentation/nmi_watchdog.txt +++ b/Documentation/nmi_watchdog.txt @@ -10,7 +10,7 @@ us to generate 'watchdog NMI interrupts'. (NMI: Non Maskable Interrupt which get executed even if the system is otherwise locked up hard). This can be used to debug hard kernel lockups. By executing periodic NMI interrupts, the kernel can monitor whether any CPU has locked up, -and print out debugging messages if so. +and print out debugging messages if so. In order to use the NMI watchdog, you need to have APIC support in your kernel. For SMP kernels, APIC support gets compiled in automatically. For @@ -22,8 +22,7 @@ CONFIG_X86_UP_IOAPIC is for uniprocessor with an IO-APIC. [Note: certain kernel debugging options, such as Kernel Stack Meter or Kernel Tracer, may implicitly disable the NMI watchdog.] -For x86-64, the needed APIC is always compiled in, and the NMI watchdog is -always enabled with I/O-APIC mode (nmi_watchdog=1). +For x86-64, the needed APIC is always compiled in. Using local APIC (nmi_watchdog=2) needs the first performance register, so you can't use it for other purposes (such as high precision performance @@ -63,16 +62,15 @@ when the system is idle), but if your system locks up on anything but the "hlt", then you are out of luck -- the event will not happen at all and the watchdog won't trigger. This is a shortcoming of the local APIC watchdog -- unfortunately there is no "clock ticks" event that would work all the -time. The I/O APIC watchdog is driven externally and has no such shortcoming. +time. The I/O APIC watchdog is driven externally and has no such shortcoming. But its NMI frequency is much higher, resulting in a more significant hit to the overall system performance. -NOTE: starting with 2.4.2-ac18 the NMI-oopser is disabled by default, -you have to enable it with a boot time parameter. Prior to 2.4.2-ac18 -the NMI-oopser is enabled unconditionally on x86 SMP boxes. +On x86 nmi_watchdog is disabled by default so you have to enable it with +a boot time parameter. -On x86-64 the NMI oopser is on by default. On 64bit Intel CPUs -it uses IO-APIC by default and on AMD it uses local APIC. +NOTE: Prior to 2.4.2-ac18 the NMI-oopser is enabled unconditionally +on x86 SMP boxes. [ feel free to send bug reports, suggestions and patches to Ingo Molnar or the Linux SMP mailing -- cgit v1.2.3 From 1bb3a029078d437aa05bda8a8c8f8ecb1265e231 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 30 Jun 2008 08:47:42 +0200 Subject: x86: nmi_watchdog - documentation fix - v2 typo fixes from Randy Dunlap and Alan Cox. Signed-off-by: Cyrill Gorcunov Signed-off-by: Ingo Molnar --- Documentation/nmi_watchdog.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/nmi_watchdog.txt b/Documentation/nmi_watchdog.txt index 101bfcf19c0d..90aa4531cb67 100644 --- a/Documentation/nmi_watchdog.txt +++ b/Documentation/nmi_watchdog.txt @@ -69,7 +69,7 @@ to the overall system performance. On x86 nmi_watchdog is disabled by default so you have to enable it with a boot time parameter. -NOTE: Prior to 2.4.2-ac18 the NMI-oopser is enabled unconditionally +NOTE: In kernels prior to 2.4.2-ac18 the NMI-oopser is enabled unconditionally on x86 SMP boxes. [ feel free to send bug reports, suggestions and patches to -- cgit v1.2.3 From 068b453834c4baf4e878481a9bd5103d54f60710 Mon Sep 17 00:00:00 2001 From: Bernhard Walle Date: Thu, 26 Jun 2008 21:55:18 +0200 Subject: x86: fix documentation bug about relocatability This patch fixes a small bug in documentation: x86_64 also has now the ability to build a relocatable kernel. Signed-off-by: Bernhard Walle Cc: vgoyal@redhat.com Cc: kexec@lists.infradead.org Signed-off-by: Ingo Molnar --- Documentation/kdump/kdump.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt index b8e52c0355d3..9691c7f5166c 100644 --- a/Documentation/kdump/kdump.txt +++ b/Documentation/kdump/kdump.txt @@ -109,7 +109,7 @@ There are two possible methods of using Kdump. 2) Or use the system kernel binary itself as dump-capture kernel and there is no need to build a separate dump-capture kernel. This is possible only with the architecutres which support a relocatable kernel. As - of today i386 and ia64 architectures support relocatable kernel. + of today, i386, x86_64 and ia64 architectures support relocatable kernel. Building a relocatable kernel is advantageous from the point of view that one does not have to build a second kernel for capturing the dump. But -- cgit v1.2.3 From 69ac9cd629ca96e59f34eb4ccd12d00b2c8276a7 Mon Sep 17 00:00:00 2001 From: Bernhard Walle Date: Fri, 27 Jun 2008 13:12:54 +0200 Subject: sysfs: add /sys/firmware/memmap This patch adds /sys/firmware/memmap interface that represents the BIOS (or Firmware) provided memory map. The tree looks like: /sys/firmware/memmap/0/start (hex number) end (hex number) type (string) ... /1/start end type With the following shell snippet one can print the memory map in the same form the kernel prints itself when booting on x86 (the E820 map). --------- 8< -------------------------- #!/bin/sh cd /sys/firmware/memmap for dir in * ; do start=$(cat $dir/start) end=$(cat $dir/end) type=$(cat $dir/type) printf "%016x-%016x (%s)\n" $start $[ $end +1] "$type" done --------- >8 -------------------------- That patch only provides the needed interface: 1. The sysfs interface. 2. The structure and enumeration definition. 3. The function firmware_map_add() and firmware_map_add_early() that should be called from architecture code (E820/EFI, for example) to add the contents to the interface. If the kernel is compiled without CONFIG_FIRMWARE_MEMMAP, the interface does nothing without cluttering the architecture-specific code with #ifdef's. The purpose of the new interface is kexec: While /proc/iomem represents the *used* memory map (e.g. modified via kernel parameters like 'memmap' and 'mem'), the /sys/firmware/memmap tree represents the unmodified memory map provided via the firmware. So kexec can: - use the original memory map for rebooting, - use the /proc/iomem for setting up the ELF core headers for kdump case that should only represent the memory of the system. The patch has been tested on i386 and x86_64. Signed-off-by: Bernhard Walle Acked-by: Greg KH Acked-by: Vivek Goyal Cc: kexec@lists.infradead.org Cc: yhlu.kernel@gmail.com Signed-off-by: Ingo Molnar --- Documentation/ABI/testing/sysfs-firmware-memmap | 71 +++++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-firmware-memmap (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-firmware-memmap b/Documentation/ABI/testing/sysfs-firmware-memmap new file mode 100644 index 000000000000..0d99ee6ae02e --- /dev/null +++ b/Documentation/ABI/testing/sysfs-firmware-memmap @@ -0,0 +1,71 @@ +What: /sys/firmware/memmap/ +Date: June 2008 +Contact: Bernhard Walle +Description: + On all platforms, the firmware provides a memory map which the + kernel reads. The resources from that memory map are registered + in the kernel resource tree and exposed to userspace via + /proc/iomem (together with other resources). + + However, on most architectures that firmware-provided memory + map is modified afterwards by the kernel itself, either because + the kernel merges that memory map with other information or + just because the user overwrites that memory map via command + line. + + kexec needs the raw firmware-provided memory map to setup the + parameter segment of the kernel that should be booted with + kexec. Also, the raw memory map is useful for debugging. For + that reason, /sys/firmware/memmap is an interface that provides + the raw memory map to userspace. + + The structure is as follows: Under /sys/firmware/memmap there + are subdirectories with the number of the entry as their name: + + /sys/firmware/memmap/0 + /sys/firmware/memmap/1 + /sys/firmware/memmap/2 + /sys/firmware/memmap/3 + ... + + The maximum depends on the number of memory map entries provided + by the firmware. The order is just the order that the firmware + provides. + + Each directory contains three files: + + start : The start address (as hexadecimal number with the + '0x' prefix). + end : The end address, inclusive (regardless whether the + firmware provides inclusive or exclusive ranges). + type : Type of the entry as string. See below for a list of + valid types. + + So, for example: + + /sys/firmware/memmap/0/start + /sys/firmware/memmap/0/end + /sys/firmware/memmap/0/type + /sys/firmware/memmap/1/start + ... + + Currently following types exist: + + - System RAM + - ACPI Tables + - ACPI Non-volatile Storage + - reserved + + Following shell snippet can be used to display that memory + map in a human-readable format: + + -------------------- 8< ---------------------------------------- + #!/bin/bash + cd /sys/firmware/memmap + for dir in * ; do + start=$(cat $dir/start) + end=$(cat $dir/end) + type=$(cat $dir/type) + printf "%016x-%016x (%s)\n" $start $[ $end +1] "$type" + done + -------------------- >8 ---------------------------------------- -- cgit v1.2.3 From 32e8d4948bb0b5f3f0ac5cdb71d0ac8e305b29a5 Mon Sep 17 00:00:00 2001 From: Vlad Yasevich Date: Tue, 8 Jul 2008 16:43:29 -0700 Subject: sctp: Add documentation for sctp sysctl variable Signed-off-by: Vlad Yasevich Acked-by: Randy Dunlap Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.txt | 170 +++++++++++++++++++++++++++++++++ 1 file changed, 170 insertions(+) (limited to 'Documentation') diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 17f1f91af35c..277437951e4d 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -1060,6 +1060,176 @@ bridge-nf-filter-pppoe-tagged - BOOLEAN Default: 1 +proc/sys/net/sctp/* Variables: + +addip_enable - BOOLEAN + Enable or disable extension of Dynamic Address Reconfiguration + (ADD-IP) functionality specified in RFC5061. This extension provides + the ability to dynamically add and remove new addresses for the SCTP + associations. + + 1: Enable extension. + + 0: Disable extension. + + Default: 0 + +addip_noauth_enable - BOOLEAN + Dynamic Address Reconfiguration (ADD-IP) requires the use of + authentication to protect the operations of adding or removing new + addresses. This requirement is mandated so that unauthorized hosts + would not be able to hijack associations. However, older + implementations may not have implemented this requirement while + allowing the ADD-IP extension. For reasons of interoperability, + we provide this variable to control the enforcement of the + authentication requirement. + + 1: Allow ADD-IP extension to be used without authentication. This + should only be set in a closed environment for interoperability + with older implementations. + + 0: Enforce the authentication requirement + + Default: 0 + +auth_enable - BOOLEAN + Enable or disable Authenticated Chunks extension. This extension + provides the ability to send and receive authenticated chunks and is + required for secure operation of Dynamic Address Reconfiguration + (ADD-IP) extension. + + 1: Enable this extension. + 0: Disable this extension. + + Default: 0 + +prsctp_enable - BOOLEAN + Enable or disable the Partial Reliability extension (RFC3758) which + is used to notify peers that a given DATA should no longer be expected. + + 1: Enable extension + 0: Disable + + Default: 1 + +max_burst - INTEGER + The limit of the number of new packets that can be initially sent. It + controls how bursty the generated traffic can be. + + Default: 4 + +association_max_retrans - INTEGER + Set the maximum number for retransmissions that an association can + attempt deciding that the remote end is unreachable. If this value + is exceeded, the association is terminated. + + Default: 10 + +max_init_retransmits - INTEGER + The maximum number of retransmissions of INIT and COOKIE-ECHO chunks + that an association will attempt before declaring the destination + unreachable and terminating. + + Default: 8 + +path_max_retrans - INTEGER + The maximum number of retransmissions that will be attempted on a given + path. Once this threshold is exceeded, the path is considered + unreachable, and new traffic will use a different path when the + association is multihomed. + + Default: 5 + +rto_initial - INTEGER + The initial round trip timeout value in milliseconds that will be used + in calculating round trip times. This is the initial time interval + for retransmissions. + + Default: 3000 + +rto_max - INTEGER + The maximum value (in milliseconds) of the round trip timeout. This + is the largest time interval that can elapse between retransmissions. + + Default: 60000 + +rto_min - INTEGER + The minimum value (in milliseconds) of the round trip timeout. This + is the smallest time interval the can elapse between retransmissions. + + Default: 1000 + +hb_interval - INTEGER + The interval (in milliseconds) between HEARTBEAT chunks. These chunks + are sent at the specified interval on idle paths to probe the state of + a given path between 2 associations. + + Default: 30000 + +sack_timeout - INTEGER + The amount of time (in milliseconds) that the implementation will wait + to send a SACK. + + Default: 200 + +valid_cookie_life - INTEGER + The default lifetime of the SCTP cookie (in milliseconds). The cookie + is used during association establishment. + + Default: 60000 + +cookie_preserve_enable - BOOLEAN + Enable or disable the ability to extend the lifetime of the SCTP cookie + that is used during the establishment phase of SCTP association + + 1: Enable cookie lifetime extension. + 0: Disable + + Default: 1 + +rcvbuf_policy - INTEGER + Determines if the receive buffer is attributed to the socket or to + association. SCTP supports the capability to create multiple + associations on a single socket. When using this capability, it is + possible that a single stalled association that's buffering a lot + of data may block other associations from delivering their data by + consuming all of the receive buffer space. To work around this, + the rcvbuf_policy could be set to attribute the receiver buffer space + to each association instead of the socket. This prevents the described + blocking. + + 1: rcvbuf space is per association + 0: recbuf space is per socket + + Default: 0 + +sndbuf_policy - INTEGER + Similar to rcvbuf_policy above, this applies to send buffer space. + + 1: Send buffer is tracked per association + 0: Send buffer is tracked per socket. + + Default: 0 + +sctp_mem - vector of 3 INTEGERs: min, pressure, max + Number of pages allowed for queueing by all SCTP sockets. + + min: Below this number of pages SCTP is not bothered about its + memory appetite. When amount of memory allocated by SCTP exceeds + this number, SCTP starts to moderate memory usage. + + pressure: This value was introduced to follow format of tcp_mem. + + max: Number of pages allowed for queueing by all SCTP sockets. + + Default is calculated at boot time from amount of available memory. + +sctp_rmem - vector of 3 INTEGERs: min, default, max + See tcp_rmem for a description. + +sctp_wmem - vector of 3 INTEGERs: min, default, max + See tcp_wmem for a description. + UNDOCUMENTED: dev_weight FIXME -- cgit v1.2.3 From eb6d42ea17329745d7d712d3aa3bb84ec1da9c85 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 10 Jul 2008 12:46:01 -0400 Subject: ftrace: Documentation This is the long awaited ftrace.txt. It explains in quite detail how to use ftrace and the various tracers. Signed-off-by: Steven Rostedt Signed-off-by: Linus Torvalds --- Documentation/ftrace.txt | 1353 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1353 insertions(+) create mode 100644 Documentation/ftrace.txt (limited to 'Documentation') diff --git a/Documentation/ftrace.txt b/Documentation/ftrace.txt new file mode 100644 index 000000000000..13e4bf054c38 --- /dev/null +++ b/Documentation/ftrace.txt @@ -0,0 +1,1353 @@ + ftrace - Function Tracer + ======================== + +Copyright 2008 Red Hat Inc. +Author: Steven Rostedt + + +Introduction +------------ + +Ftrace is an internal tracer designed to help out developers and +designers of systems to find what is going on inside the kernel. +It can be used for debugging or analyzing latencies and performance +issues that take place outside of user-space. + +Although ftrace is the function tracer, it also includes an +infrastructure that allows for other types of tracing. Some of the +tracers that are currently in ftrace is a tracer to trace +context switches, the time it takes for a high priority task to +run after it was woken up, the time interrupts are disabled, and +more. + + +The File System +--------------- + +Ftrace uses the debugfs file system to hold the control files as well +as the files to display output. + +To mount the debugfs system: + + # mkdir /debug + # mount -t debugfs nodev /debug + + +That's it! (assuming that you have ftrace configured into your kernel) + +After mounting the debugfs, you can see a directory called +"tracing". This directory contains the control and output files +of ftrace. Here is a list of some of the key files: + + + Note: all time values are in microseconds. + + current_tracer : This is used to set or display the current tracer + that is configured. + + available_tracers : This holds the different types of tracers that + has been compiled into the kernel. The tracers + listed here can be configured by echoing in their + name into current_tracer. + + tracing_enabled : This sets or displays whether the current_tracer + is activated and tracing or not. Echo 0 into this + file to disable the tracer or 1 (or non-zero) to + enable it. + + trace : This file holds the output of the trace in a human readable + format. + + latency_trace : This file shows the same trace but the information + is organized more to display possible latencies + in the system. + + trace_pipe : The output is the same as the "trace" file but this + file is meant to be streamed with live tracing. + Reads from this file will block until new data + is retrieved. Unlike the "trace" and "latency_trace" + files, this file is a consumer. This means reading + from this file causes sequential reads to display + more current data. Once data is read from this + file, it is consumed, and will not be read + again with a sequential read. The "trace" and + "latency_trace" files are static, and if the + tracer isn't adding more data, they will display + the same information every time they are read. + + iter_ctrl : This file lets the user control the amount of data + that is displayed in one of the above output + files. + + trace_max_latency : Some of the tracers record the max latency. + For example, the time interrupts are disabled. + This time is saved in this file. The max trace + will also be stored, and displayed by either + "trace" or "latency_trace". A new max trace will + only be recorded if the latency is greater than + the value in this file. (in microseconds) + + trace_entries : This sets or displays the number of trace + entries each CPU buffer can hold. The tracer buffers + are the same size for each CPU, so care must be + taken when modifying the trace_entries. The number + of actually entries will be the number given + times the number of possible CPUS. The buffers + are saved as individual pages, and the actual entries + will always be rounded up to entries per page. + + This can only be updated when the current_tracer + is set to "none". + + NOTE: It is planned on changing the allocated buffers + from being the number of possible CPUS to + the number of online CPUS. + + tracing_cpumask : This is a mask that lets the user only trace + on specified CPUS. The format is a hex string + representing the CPUS. + + set_ftrace_filter : When dynamic ftrace is configured in, the + code is dynamically modified to disable calling + of the function profiler (mcount). This lets + tracing be configured in with practically no overhead + in performance. This also has a side effect of + enabling or disabling specific functions to be + traced. Echoing in names of functions into this + file will limit the trace to only those files. + + set_ftrace_notrace: This has the opposite effect that + set_ftrace_filter has. Any function that is added + here will not be traced. If a function exists + in both set_ftrace_filter and set_ftrace_notrace + the function will _not_ bet traced. + + available_filter_functions : When a function is encountered the first + time by the dynamic tracer, it is recorded and + later the call is converted into a nop. This file + lists the functions that have been recorded + by the dynamic tracer and these functions can + be used to set the ftrace filter by the above + "set_ftrace_filter" file. + + +The Tracers +----------- + +Here are the list of current tracers that can be configured. + + ftrace - function tracer that uses mcount to trace all functions. + It is possible to filter out which functions that are + traced when dynamic ftrace is configured in. + + sched_switch - traces the context switches between tasks. + + irqsoff - traces the areas that disable interrupts and saves off + the trace with the longest max latency. + See tracing_max_latency. When a new max is recorded, + it replaces the old trace. It is best to view this + trace with the latency_trace file. + + preemptoff - Similar to irqsoff but traces and records the time + preemption is disabled. + + preemptirqsoff - Similar to irqsoff and preemptoff, but traces and + records the largest time irqs and/or preemption is + disabled. + + wakeup - Traces and records the max latency that it takes for + the highest priority task to get scheduled after + it has been woken up. + + none - This is not a tracer. To remove all tracers from tracing + simply echo "none" into current_tracer. + + +Examples of using the tracer +---------------------------- + +Here are typical examples of using the tracers with only controlling +them with the debugfs interface (without using any user-land utilities). + +Output format: +-------------- + +Here's an example of the output format of the file "trace" + + -------- +# tracer: ftrace +# +# TASK-PID CPU# TIMESTAMP FUNCTION +# | | | | | + bash-4251 [01] 10152.583854: path_put <-path_walk + bash-4251 [01] 10152.583855: dput <-path_put + bash-4251 [01] 10152.583855: _atomic_dec_and_lock <-dput + -------- + +A header is printed with the trace that is represented. In this case +the tracer is "ftrace". Then a header showing the format. Task name +"bash", the task PID "4251", the CPU that it was running on +"01", the timestamp in . format, the function name that was +traced "path_put" and the parent function that called this function +"path_walk". + +The sched_switch tracer also includes tracing of task wake ups and +context switches. + + ksoftirqd/1-7 [01] 1453.070013: 7:115:R + 2916:115:S + ksoftirqd/1-7 [01] 1453.070013: 7:115:R + 10:115:S + ksoftirqd/1-7 [01] 1453.070013: 7:115:R ==> 10:115:R + events/1-10 [01] 1453.070013: 10:115:S ==> 2916:115:R + kondemand/1-2916 [01] 1453.070013: 2916:115:S ==> 7:115:R + ksoftirqd/1-7 [01] 1453.070013: 7:115:S ==> 0:140:R + +Wake ups are represented by a "+" and the context switches show +"==>". The format is: + + Context switches: + + Previous task Next Task + + :: ==> :: + + Wake ups: + + Current task Task waking up + + :: + :: + +The prio is the internal kernel priority, which is inverse to the +priority that is usually displayed by user-space tools. Zero represents +the highest priority (99). Prio 100 starts the "nice" priorities with +100 being equal to nice -20 and 139 being nice 19. The prio "140" is +reserved for the idle task which is the lowest priority thread (pid 0). + + +Latency trace format +-------------------- + +For traces that display latency times, the latency_trace file gives +a bit more information to see why a latency happened. Here's a typical +trace. + +# tracer: irqsoff +# +irqsoff latency trace v1.1.5 on 2.6.26-rc8 +-------------------------------------------------------------------- + latency: 97 us, #3/3, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) + ----------------- + | task: swapper-0 (uid:0 nice:0 policy:0 rt_prio:0) + ----------------- + => started at: apic_timer_interrupt + => ended at: do_softirq + +# _------=> CPU# +# / _-----=> irqs-off +# | / _----=> need-resched +# || / _---=> hardirq/softirq +# ||| / _--=> preempt-depth +# |||| / +# ||||| delay +# cmd pid ||||| time | caller +# \ / ||||| \ | / + -0 0d..1 0us+: trace_hardirqs_off_thunk (apic_timer_interrupt) + -0 0d.s. 97us : __do_softirq (do_softirq) + -0 0d.s1 98us : trace_hardirqs_on (do_softirq) + + +vim:ft=help + + +This shows that the current tracer is "irqsoff" tracing the time +interrupts are disabled. It gives the trace version and the kernel +this was executed on (2.6.26-rc8). Then it displays the max latency +in microsecs (97 us). The number of trace entries displayed +by the total number recorded (both are three: #3/3). The type of +preemption that was used (PREEMPT). VP, KP, SP, and HP are always zero +and reserved for later use. #P is the number of online CPUS (#P:2). + +The task is the process that was running when the latency happened. +(swapper pid: 0). + +The start and stop that caused the latencies: + + apic_timer_interrupt is where the interrupts were disabled. + do_softirq is where they were enabled again. + +The next lines after the header are the trace itself. The header +explains which is which. + + cmd: The name of the process in the trace. + + pid: The PID of that process. + + CPU#: The CPU that the process was running on. + + irqs-off: 'd' interrupts are disabled. '.' otherwise. + + need-resched: 'N' task need_resched is set, '.' otherwise. + + hardirq/softirq: + 'H' - hard irq happened inside a softirq. + 'h' - hard irq is running + 's' - soft irq is running + '.' - normal context. + + preempt-depth: The level of preempt_disabled + +The above is mostly meaningful for kernel developers. + + time: This differs from the trace output where as the trace output + contained a absolute timestamp. This timestamp is relative + to the start of the first entry in the the trace. + + delay: This is just to help catch your eye a bit better. And + needs to be fixed to be only relative to the same CPU. + The marks is determined by the difference between this + current trace and the next trace. + '!' - greater than preempt_mark_thresh (default 100) + '+' - greater than 1 microsecond + ' ' - less than or equal to 1 microsecond. + + The rest is the same as the 'trace' file. + + +iter_ctrl +--------- + +The iter_ctrl file is used to control what gets printed in the trace +output. To see what is available, simply cat the file: + + cat /debug/tracing/iter_ctrl + print-parent nosym-offset nosym-addr noverbose noraw nohex nobin \ + noblock nostacktrace nosched-tree + +To disable one of the options, echo in the option appended with "no". + + echo noprint-parent > /debug/tracing/iter_ctrl + +To enable an option, leave off the "no". + + echo sym-offest > /debug/tracing/iter_ctrl + +Here are the available options: + + print-parent - On function traces, display the calling function + as well as the function being traced. + + print-parent: + bash-4000 [01] 1477.606694: simple_strtoul <-strict_strtoul + + noprint-parent: + bash-4000 [01] 1477.606694: simple_strtoul + + + sym-offset - Display not only the function name, but also the offset + in the function. For example, instead of seeing just + "ktime_get" you will see "ktime_get+0xb/0x20" + + sym-offset: + bash-4000 [01] 1477.606694: simple_strtoul+0x6/0xa0 + + sym-addr - this will also display the function address as well as + the function name. + + sym-addr: + bash-4000 [01] 1477.606694: simple_strtoul + + verbose - This deals with the latency_trace file. + + bash 4000 1 0 00000000 00010a95 [58127d26] 1720.415ms \ + (+0.000ms): simple_strtoul (strict_strtoul) + + raw - This will display raw numbers. This option is best for use with + user applications that can translate the raw numbers better than + having it done in the kernel. + + hex - similar to raw, but the numbers will be in a hexadecimal format. + + bin - This will print out the formats in raw binary. + + block - TBD (needs update) + + stacktrace - This is one of the options that changes the trace itself. + When a trace is recorded, so is the stack of functions. + This allows for back traces of trace sites. + + sched-tree - TBD (any users??) + + +sched_switch +------------ + +This tracer simply records schedule switches. Here's an example +on how to implement it. + + # echo sched_switch > /debug/tracing/current_tracer + # echo 1 > /debug/tracing/tracing_enabled + # sleep 1 + # echo 0 > /debug/tracing/tracing_enabled + # cat /debug/tracing/trace + +# tracer: sched_switch +# +# TASK-PID CPU# TIMESTAMP FUNCTION +# | | | | | + bash-3997 [01] 240.132281: 3997:120:R + 4055:120:R + bash-3997 [01] 240.132284: 3997:120:R ==> 4055:120:R + sleep-4055 [01] 240.132371: 4055:120:S ==> 3997:120:R + bash-3997 [01] 240.132454: 3997:120:R + 4055:120:S + bash-3997 [01] 240.132457: 3997:120:R ==> 4055:120:R + sleep-4055 [01] 240.132460: 4055:120:D ==> 3997:120:R + bash-3997 [01] 240.132463: 3997:120:R + 4055:120:D + bash-3997 [01] 240.132465: 3997:120:R ==> 4055:120:R + -0 [00] 240.132589: 0:140:R + 4:115:S + -0 [00] 240.132591: 0:140:R ==> 4:115:R + ksoftirqd/0-4 [00] 240.132595: 4:115:S ==> 0:140:R + -0 [00] 240.132598: 0:140:R + 4:115:S + -0 [00] 240.132599: 0:140:R ==> 4:115:R + ksoftirqd/0-4 [00] 240.132603: 4:115:S ==> 0:140:R + sleep-4055 [01] 240.133058: 4055:120:S ==> 3997:120:R + [...] + + +As we have discussed previously about this format, the header shows +the name of the trace and points to the options. The "FUNCTION" +is a misnomer since here it represents the wake ups and context +switches. + +The sched_switch only lists the wake ups (represented with '+') +and context switches ('==>') with the previous task or current +first followed by the next task or task waking up. The format for both +of these is PID:KERNEL-PRIO:TASK-STATE. Remember that the KERNEL-PRIO +is the inverse of the actual priority with zero (0) being the highest +priority and the nice values starting at 100 (nice -20). Below is +a quick chart to map the kernel priority to user land priorities. + + Kernel priority: 0 to 99 ==> user RT priority 99 to 0 + Kernel priority: 100 to 139 ==> user nice -20 to 19 + Kernel priority: 140 ==> idle task priority + +The task states are: + + R - running : wants to run, may not actually be running + S - sleep : process is waiting to be woken up (handles signals) + D - deep sleep : process must be woken up (ignores signals) + T - stopped : process suspended + t - traced : process is being traced (with something like gdb) + Z - zombie : process waiting to be cleaned up + X - unknown + + +ftrace_enabled +-------------- + +The following tracers give different output depending on whether +or not the sysctl ftrace_enabled is set. To set ftrace_enabled, +one can either use the sysctl function or set it via the proc +file system interface. + + sysctl kernel.ftrace_enabled=1 + + or + + echo 1 > /proc/sys/kernel/ftrace_enabled + +To disable ftrace_enabled simply replace the '1' with '0' in +the above commands. + +When ftrace_enabled is set the tracers will also record the functions +that are within the trace. The descriptions of the tracers +will also show an example with ftrace enabled. + + +irqsoff +------- + +When interrupts are disabled, the CPU can not react to any other +external event (besides NMIs and SMIs). This prevents the timer +interrupt from triggering or the mouse interrupt from letting the +kernel know of a new mouse event. The result is a latency with the +reaction time. + +The irqsoff tracer tracks the time interrupts are disabled and when +they are re-enabled. When a new maximum latency is hit, it saves off +the trace so that it may be retrieved at a later time. Every time a +new maximum in reached, the old saved trace is discarded and the new +trace is saved. + +To reset the maximum, echo 0 into tracing_max_latency. Here's an +example: + + # echo irqsoff > /debug/tracing/current_tracer + # echo 0 > /debug/tracing/tracing_max_latency + # echo 1 > /debug/tracing/tracing_enabled + # ls -ltr + [...] + # echo 0 > /debug/tracing/tracing_enabled + # cat /debug/tracing/latency_trace +# tracer: irqsoff +# +irqsoff latency trace v1.1.5 on 2.6.26-rc8 +-------------------------------------------------------------------- + latency: 6 us, #3/3, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) + ----------------- + | task: bash-4269 (uid:0 nice:0 policy:0 rt_prio:0) + ----------------- + => started at: copy_page_range + => ended at: copy_page_range + +# _------=> CPU# +# / _-----=> irqs-off +# | / _----=> need-resched +# || / _---=> hardirq/softirq +# ||| / _--=> preempt-depth +# |||| / +# ||||| delay +# cmd pid ||||| time | caller +# \ / ||||| \ | / + bash-4269 1...1 0us+: _spin_lock (copy_page_range) + bash-4269 1...1 7us : _spin_unlock (copy_page_range) + bash-4269 1...2 7us : trace_preempt_on (copy_page_range) + + +vim:ft=help + +Here we see that that we had a latency of 6 microsecs (which is +very good). The spin_lock in copy_page_range disabled interrupts. +The difference between the 6 and the displayed timestamp 7us is +because the clock must have incremented between the time of recording +the max latency and recording the function that had that latency. + +Note the above had ftrace_enabled not set. If we set the ftrace_enabled +we get a much larger output: + +# tracer: irqsoff +# +irqsoff latency trace v1.1.5 on 2.6.26-rc8 +-------------------------------------------------------------------- + latency: 50 us, #101/101, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) + ----------------- + | task: ls-4339 (uid:0 nice:0 policy:0 rt_prio:0) + ----------------- + => started at: __alloc_pages_internal + => ended at: __alloc_pages_internal + +# _------=> CPU# +# / _-----=> irqs-off +# | / _----=> need-resched +# || / _---=> hardirq/softirq +# ||| / _--=> preempt-depth +# |||| / +# ||||| delay +# cmd pid ||||| time | caller +# \ / ||||| \ | / + ls-4339 0...1 0us+: get_page_from_freelist (__alloc_pages_internal) + ls-4339 0d..1 3us : rmqueue_bulk (get_page_from_freelist) + ls-4339 0d..1 3us : _spin_lock (rmqueue_bulk) + ls-4339 0d..1 4us : add_preempt_count (_spin_lock) + ls-4339 0d..2 4us : __rmqueue (rmqueue_bulk) + ls-4339 0d..2 5us : __rmqueue_smallest (__rmqueue) + ls-4339 0d..2 5us : __mod_zone_page_state (__rmqueue_smallest) + ls-4339 0d..2 6us : __rmqueue (rmqueue_bulk) + ls-4339 0d..2 6us : __rmqueue_smallest (__rmqueue) + ls-4339 0d..2 7us : __mod_zone_page_state (__rmqueue_smallest) + ls-4339 0d..2 7us : __rmqueue (rmqueue_bulk) + ls-4339 0d..2 8us : __rmqueue_smallest (__rmqueue) +[...] + ls-4339 0d..2 46us : __rmqueue_smallest (__rmqueue) + ls-4339 0d..2 47us : __mod_zone_page_state (__rmqueue_smallest) + ls-4339 0d..2 47us : __rmqueue (rmqueue_bulk) + ls-4339 0d..2 48us : __rmqueue_smallest (__rmqueue) + ls-4339 0d..2 48us : __mod_zone_page_state (__rmqueue_smallest) + ls-4339 0d..2 49us : _spin_unlock (rmqueue_bulk) + ls-4339 0d..2 49us : sub_preempt_count (_spin_unlock) + ls-4339 0d..1 50us : get_page_from_freelist (__alloc_pages_internal) + ls-4339 0d..2 51us : trace_hardirqs_on (__alloc_pages_internal) + + +vim:ft=help + + +Here we traced a 50 microsecond latency. But we also see all the +functions that were called during that time. Note that enabling +function tracing we endure an added overhead. This overhead may +extend the latency times. But never the less, this trace has provided +some very helpful debugging. + + +preemptoff +---------- + +When preemption is disabled we may be able to receive interrupts but +the task can not be preempted and a higher priority task must wait +for preemption to be enabled again before it can preempt a lower +priority task. + +The preemptoff tracer traces the places that disables preemption. +Like the irqsoff, it records the maximum latency that preemption +was disabled. The control of preemptoff is much like the irqsoff. + + # echo preemptoff > /debug/tracing/current_tracer + # echo 0 > /debug/tracing/tracing_max_latency + # echo 1 > /debug/tracing/tracing_enabled + # ls -ltr + [...] + # echo 0 > /debug/tracing/tracing_enabled + # cat /debug/tracing/latency_trace +# tracer: preemptoff +# +preemptoff latency trace v1.1.5 on 2.6.26-rc8 +-------------------------------------------------------------------- + latency: 29 us, #3/3, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) + ----------------- + | task: sshd-4261 (uid:0 nice:0 policy:0 rt_prio:0) + ----------------- + => started at: do_IRQ + => ended at: __do_softirq + +# _------=> CPU# +# / _-----=> irqs-off +# | / _----=> need-resched +# || / _---=> hardirq/softirq +# ||| / _--=> preempt-depth +# |||| / +# ||||| delay +# cmd pid ||||| time | caller +# \ / ||||| \ | / + sshd-4261 0d.h. 0us+: irq_enter (do_IRQ) + sshd-4261 0d.s. 29us : _local_bh_enable (__do_softirq) + sshd-4261 0d.s1 30us : trace_preempt_on (__do_softirq) + + +vim:ft=help + +This has some more changes. Preemption was disabled when an interrupt +came in (notice the 'h'), and was enabled while doing a softirq. +(notice the 's'). But we also see that interrupts have been disabled +when entering the preempt off section and leaving it (the 'd'). +We do not know if interrupts were enabled in the mean time. + +# tracer: preemptoff +# +preemptoff latency trace v1.1.5 on 2.6.26-rc8 +-------------------------------------------------------------------- + latency: 63 us, #87/87, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) + ----------------- + | task: sshd-4261 (uid:0 nice:0 policy:0 rt_prio:0) + ----------------- + => started at: remove_wait_queue + => ended at: __do_softirq + +# _------=> CPU# +# / _-----=> irqs-off +# | / _----=> need-resched +# || / _---=> hardirq/softirq +# ||| / _--=> preempt-depth +# |||| / +# ||||| delay +# cmd pid ||||| time | caller +# \ / ||||| \ | / + sshd-4261 0d..1 0us : _spin_lock_irqsave (remove_wait_queue) + sshd-4261 0d..1 1us : _spin_unlock_irqrestore (remove_wait_queue) + sshd-4261 0d..1 2us : do_IRQ (common_interrupt) + sshd-4261 0d..1 2us : irq_enter (do_IRQ) + sshd-4261 0d..1 2us : idle_cpu (irq_enter) + sshd-4261 0d..1 3us : add_preempt_count (irq_enter) + sshd-4261 0d.h1 3us : idle_cpu (irq_enter) + sshd-4261 0d.h. 4us : handle_fasteoi_irq (do_IRQ) +[...] + sshd-4261 0d.h. 12us : add_preempt_count (_spin_lock) + sshd-4261 0d.h1 12us : ack_ioapic_quirk_irq (handle_fasteoi_irq) + sshd-4261 0d.h1 13us : move_native_irq (ack_ioapic_quirk_irq) + sshd-4261 0d.h1 13us : _spin_unlock (handle_fasteoi_irq) + sshd-4261 0d.h1 14us : sub_preempt_count (_spin_unlock) + sshd-4261 0d.h1 14us : irq_exit (do_IRQ) + sshd-4261 0d.h1 15us : sub_preempt_count (irq_exit) + sshd-4261 0d..2 15us : do_softirq (irq_exit) + sshd-4261 0d... 15us : __do_softirq (do_softirq) + sshd-4261 0d... 16us : __local_bh_disable (__do_softirq) + sshd-4261 0d... 16us+: add_preempt_count (__local_bh_disable) + sshd-4261 0d.s4 20us : add_preempt_count (__local_bh_disable) + sshd-4261 0d.s4 21us : sub_preempt_count (local_bh_enable) + sshd-4261 0d.s5 21us : sub_preempt_count (local_bh_enable) +[...] + sshd-4261 0d.s6 41us : add_preempt_count (__local_bh_disable) + sshd-4261 0d.s6 42us : sub_preempt_count (local_bh_enable) + sshd-4261 0d.s7 42us : sub_preempt_count (local_bh_enable) + sshd-4261 0d.s5 43us : add_preempt_count (__local_bh_disable) + sshd-4261 0d.s5 43us : sub_preempt_count (local_bh_enable_ip) + sshd-4261 0d.s6 44us : sub_preempt_count (local_bh_enable_ip) + sshd-4261 0d.s5 44us : add_preempt_count (__local_bh_disable) + sshd-4261 0d.s5 45us : sub_preempt_count (local_bh_enable) +[...] + sshd-4261 0d.s. 63us : _local_bh_enable (__do_softirq) + sshd-4261 0d.s1 64us : trace_preempt_on (__do_softirq) + + +The above is an example of the preemptoff trace with ftrace_enabled +set. Here we see that interrupts were disabled the entire time. +The irq_enter code lets us know that we entered an interrupt 'h'. +Before that, the functions being traced still show that it is not +in an interrupt, but we can see by the functions themselves that +this is not the case. + +Notice that the __do_softirq when called doesn't have a preempt_count. +It may seem that we missed a preempt enabled. What really happened +is that the preempt count is held on the threads stack and we +switched to the softirq stack (4K stacks in effect). The code +does not copy the preempt count, but because interrupts are disabled +we don't need to worry about it. Having a tracer like this is good +to let people know what really happens inside the kernel. + + +preemptirqsoff +-------------- + +Knowing the locations that have interrupts disabled or preemption +disabled for the longest times is helpful. But sometimes we would +like to know when either preemption and/or interrupts are disabled. + +The following code: + + local_irq_disable(); + call_function_with_irqs_off(); + preempt_disable(); + call_function_with_irqs_and_preemption_off(); + local_irq_enable(); + call_function_with_preemption_off(); + preempt_enable(); + +The irqsoff tracer will record the total length of +call_function_with_irqs_off() and +call_function_with_irqs_and_preemption_off(). + +The preemptoff tracer will record the total length of +call_function_with_irqs_and_preemption_off() and +call_function_with_preemption_off(). + +But neither will trace the time that interrupts and/or preemption +is disabled. This total time is the time that we can not schedule. +To record this time, use the preemptirqsoff tracer. + +Again, using this trace is much like the irqsoff and preemptoff tracers. + + # echo preemptoff > /debug/tracing/current_tracer + # echo 0 > /debug/tracing/tracing_max_latency + # echo 1 > /debug/tracing/tracing_enabled + # ls -ltr + [...] + # echo 0 > /debug/tracing/tracing_enabled + # cat /debug/tracing/latency_trace +# tracer: preemptirqsoff +# +preemptirqsoff latency trace v1.1.5 on 2.6.26-rc8 +-------------------------------------------------------------------- + latency: 293 us, #3/3, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) + ----------------- + | task: ls-4860 (uid:0 nice:0 policy:0 rt_prio:0) + ----------------- + => started at: apic_timer_interrupt + => ended at: __do_softirq + +# _------=> CPU# +# / _-----=> irqs-off +# | / _----=> need-resched +# || / _---=> hardirq/softirq +# ||| / _--=> preempt-depth +# |||| / +# ||||| delay +# cmd pid ||||| time | caller +# \ / ||||| \ | / + ls-4860 0d... 0us!: trace_hardirqs_off_thunk (apic_timer_interrupt) + ls-4860 0d.s. 294us : _local_bh_enable (__do_softirq) + ls-4860 0d.s1 294us : trace_preempt_on (__do_softirq) + + +vim:ft=help + + +The trace_hardirqs_off_thunk is called from assembly on x86 when +interrupts are disabled in the assembly code. Without the function +tracing, we don't know if interrupts were enabled within the preemption +points. We do see that it started with preemption enabled. + +Here is a trace with ftrace_enabled set: + + +# tracer: preemptirqsoff +# +preemptirqsoff latency trace v1.1.5 on 2.6.26-rc8 +-------------------------------------------------------------------- + latency: 105 us, #183/183, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) + ----------------- + | task: sshd-4261 (uid:0 nice:0 policy:0 rt_prio:0) + ----------------- + => started at: write_chan + => ended at: __do_softirq + +# _------=> CPU# +# / _-----=> irqs-off +# | / _----=> need-resched +# || / _---=> hardirq/softirq +# ||| / _--=> preempt-depth +# |||| / +# ||||| delay +# cmd pid ||||| time | caller +# \ / ||||| \ | / + ls-4473 0.N.. 0us : preempt_schedule (write_chan) + ls-4473 0dN.1 1us : _spin_lock (schedule) + ls-4473 0dN.1 2us : add_preempt_count (_spin_lock) + ls-4473 0d..2 2us : put_prev_task_fair (schedule) +[...] + ls-4473 0d..2 13us : set_normalized_timespec (ktime_get_ts) + ls-4473 0d..2 13us : __switch_to (schedule) + sshd-4261 0d..2 14us : finish_task_switch (schedule) + sshd-4261 0d..2 14us : _spin_unlock_irq (finish_task_switch) + sshd-4261 0d..1 15us : add_preempt_count (_spin_lock_irqsave) + sshd-4261 0d..2 16us : _spin_unlock_irqrestore (hrtick_set) + sshd-4261 0d..2 16us : do_IRQ (common_interrupt) + sshd-4261 0d..2 17us : irq_enter (do_IRQ) + sshd-4261 0d..2 17us : idle_cpu (irq_enter) + sshd-4261 0d..2 18us : add_preempt_count (irq_enter) + sshd-4261 0d.h2 18us : idle_cpu (irq_enter) + sshd-4261 0d.h. 18us : handle_fasteoi_irq (do_IRQ) + sshd-4261 0d.h. 19us : _spin_lock (handle_fasteoi_irq) + sshd-4261 0d.h. 19us : add_preempt_count (_spin_lock) + sshd-4261 0d.h1 20us : _spin_unlock (handle_fasteoi_irq) + sshd-4261 0d.h1 20us : sub_preempt_count (_spin_unlock) +[...] + sshd-4261 0d.h1 28us : _spin_unlock (handle_fasteoi_irq) + sshd-4261 0d.h1 29us : sub_preempt_count (_spin_unlock) + sshd-4261 0d.h2 29us : irq_exit (do_IRQ) + sshd-4261 0d.h2 29us : sub_preempt_count (irq_exit) + sshd-4261 0d..3 30us : do_softirq (irq_exit) + sshd-4261 0d... 30us : __do_softirq (do_softirq) + sshd-4261 0d... 31us : __local_bh_disable (__do_softirq) + sshd-4261 0d... 31us+: add_preempt_count (__local_bh_disable) + sshd-4261 0d.s4 34us : add_preempt_count (__local_bh_disable) +[...] + sshd-4261 0d.s3 43us : sub_preempt_count (local_bh_enable_ip) + sshd-4261 0d.s4 44us : sub_preempt_count (local_bh_enable_ip) + sshd-4261 0d.s3 44us : smp_apic_timer_interrupt (apic_timer_interrupt) + sshd-4261 0d.s3 45us : irq_enter (smp_apic_timer_interrupt) + sshd-4261 0d.s3 45us : idle_cpu (irq_enter) + sshd-4261 0d.s3 46us : add_preempt_count (irq_enter) + sshd-4261 0d.H3 46us : idle_cpu (irq_enter) + sshd-4261 0d.H3 47us : hrtimer_interrupt (smp_apic_timer_interrupt) + sshd-4261 0d.H3 47us : ktime_get (hrtimer_interrupt) +[...] + sshd-4261 0d.H3 81us : tick_program_event (hrtimer_interrupt) + sshd-4261 0d.H3 82us : ktime_get (tick_program_event) + sshd-4261 0d.H3 82us : ktime_get_ts (ktime_get) + sshd-4261 0d.H3 83us : getnstimeofday (ktime_get_ts) + sshd-4261 0d.H3 83us : set_normalized_timespec (ktime_get_ts) + sshd-4261 0d.H3 84us : clockevents_program_event (tick_program_event) + sshd-4261 0d.H3 84us : lapic_next_event (clockevents_program_event) + sshd-4261 0d.H3 85us : irq_exit (smp_apic_timer_interrupt) + sshd-4261 0d.H3 85us : sub_preempt_count (irq_exit) + sshd-4261 0d.s4 86us : sub_preempt_count (irq_exit) + sshd-4261 0d.s3 86us : add_preempt_count (__local_bh_disable) +[...] + sshd-4261 0d.s1 98us : sub_preempt_count (net_rx_action) + sshd-4261 0d.s. 99us : add_preempt_count (_spin_lock_irq) + sshd-4261 0d.s1 99us+: _spin_unlock_irq (run_timer_softirq) + sshd-4261 0d.s. 104us : _local_bh_enable (__do_softirq) + sshd-4261 0d.s. 104us : sub_preempt_count (_local_bh_enable) + sshd-4261 0d.s. 105us : _local_bh_enable (__do_softirq) + sshd-4261 0d.s1 105us : trace_preempt_on (__do_softirq) + + +This is a very interesting trace. It started with the preemption of +the ls task. We see that the task had the "need_resched" bit set +with the 'N' in the trace. Interrupts are disabled in the spin_lock +and the trace started. We see that a schedule took place to run +sshd. When the interrupts were enabled we took an interrupt. +On return of the interrupt the softirq ran. We took another interrupt +while running the softirq as we see with the capital 'H'. + + +wakeup +------ + +In Real-Time environment it is very important to know the wakeup +time it takes for the highest priority task that wakes up to the +time it executes. This is also known as "schedule latency". +I stress the point that this is about RT tasks. It is also important +to know the scheduling latency of non-RT tasks, but the average +schedule latency is better for non-RT tasks. Tools like +LatencyTop is more appropriate for such measurements. + +Real-Time environments is interested in the worst case latency. +That is the longest latency it takes for something to happen, and +not the average. We can have a very fast scheduler that may only +have a large latency once in a while, but that would not work well +with Real-Time tasks. The wakeup tracer was designed to record +the worst case wakeups of RT tasks. Non-RT tasks are not recorded +because the tracer only records one worst case and tracing non-RT +tasks that are unpredictable will overwrite the worst case latency +of RT tasks. + +Since this tracer only deals with RT tasks, we will run this slightly +different than we did with the previous tracers. Instead of performing +an 'ls' we will run 'sleep 1' under 'chrt' which changes the +priority of the task. + + # echo wakeup > /debug/tracing/current_tracer + # echo 0 > /debug/tracing/tracing_max_latency + # echo 1 > /debug/tracing/tracing_enabled + # chrt -f 5 sleep 1 + # echo 0 > /debug/tracing/tracing_enabled + # cat /debug/tracing/latency_trace +# tracer: wakeup +# +wakeup latency trace v1.1.5 on 2.6.26-rc8 +-------------------------------------------------------------------- + latency: 4 us, #2/2, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) + ----------------- + | task: sleep-4901 (uid:0 nice:0 policy:1 rt_prio:5) + ----------------- + +# _------=> CPU# +# / _-----=> irqs-off +# | / _----=> need-resched +# || / _---=> hardirq/softirq +# ||| / _--=> preempt-depth +# |||| / +# ||||| delay +# cmd pid ||||| time | caller +# \ / ||||| \ | / + -0 1d.h4 0us+: try_to_wake_up (wake_up_process) + -0 1d..4 4us : schedule (cpu_idle) + + +vim:ft=help + + +Running this on an idle system we see that it only took 4 microseconds +to perform the task switch. Note, since the trace marker in the +schedule is before the actual "switch" we stop the tracing when +the recorded task is about to schedule in. This may change if +we add a new marker at the end of the scheduler. + +Notice that the recorded task is 'sleep' with the PID of 4901 and it +has an rt_prio of 5. This priority is user-space priority and not +the internal kernel priority. The policy is 1 for SCHED_FIFO and 2 +for SCHED_RR. + +Doing the same with chrt -r 5 and ftrace_enabled set. + +# tracer: wakeup +# +wakeup latency trace v1.1.5 on 2.6.26-rc8 +-------------------------------------------------------------------- + latency: 50 us, #60/60, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) + ----------------- + | task: sleep-4068 (uid:0 nice:0 policy:2 rt_prio:5) + ----------------- + +# _------=> CPU# +# / _-----=> irqs-off +# | / _----=> need-resched +# || / _---=> hardirq/softirq +# ||| / _--=> preempt-depth +# |||| / +# ||||| delay +# cmd pid ||||| time | caller +# \ / ||||| \ | / +ksoftirq-7 1d.H3 0us : try_to_wake_up (wake_up_process) +ksoftirq-7 1d.H4 1us : sub_preempt_count (marker_probe_cb) +ksoftirq-7 1d.H3 2us : check_preempt_wakeup (try_to_wake_up) +ksoftirq-7 1d.H3 3us : update_curr (check_preempt_wakeup) +ksoftirq-7 1d.H3 4us : calc_delta_mine (update_curr) +ksoftirq-7 1d.H3 5us : __resched_task (check_preempt_wakeup) +ksoftirq-7 1d.H3 6us : task_wake_up_rt (try_to_wake_up) +ksoftirq-7 1d.H3 7us : _spin_unlock_irqrestore (try_to_wake_up) +[...] +ksoftirq-7 1d.H2 17us : irq_exit (smp_apic_timer_interrupt) +ksoftirq-7 1d.H2 18us : sub_preempt_count (irq_exit) +ksoftirq-7 1d.s3 19us : sub_preempt_count (irq_exit) +ksoftirq-7 1..s2 20us : rcu_process_callbacks (__do_softirq) +[...] +ksoftirq-7 1..s2 26us : __rcu_process_callbacks (rcu_process_callbacks) +ksoftirq-7 1d.s2 27us : _local_bh_enable (__do_softirq) +ksoftirq-7 1d.s2 28us : sub_preempt_count (_local_bh_enable) +ksoftirq-7 1.N.3 29us : sub_preempt_count (ksoftirqd) +ksoftirq-7 1.N.2 30us : _cond_resched (ksoftirqd) +ksoftirq-7 1.N.2 31us : __cond_resched (_cond_resched) +ksoftirq-7 1.N.2 32us : add_preempt_count (__cond_resched) +ksoftirq-7 1.N.2 33us : schedule (__cond_resched) +ksoftirq-7 1.N.2 33us : add_preempt_count (schedule) +ksoftirq-7 1.N.3 34us : hrtick_clear (schedule) +ksoftirq-7 1dN.3 35us : _spin_lock (schedule) +ksoftirq-7 1dN.3 36us : add_preempt_count (_spin_lock) +ksoftirq-7 1d..4 37us : put_prev_task_fair (schedule) +ksoftirq-7 1d..4 38us : update_curr (put_prev_task_fair) +[...] +ksoftirq-7 1d..5 47us : _spin_trylock (tracing_record_cmdline) +ksoftirq-7 1d..5 48us : add_preempt_count (_spin_trylock) +ksoftirq-7 1d..6 49us : _spin_unlock (tracing_record_cmdline) +ksoftirq-7 1d..6 49us : sub_preempt_count (_spin_unlock) +ksoftirq-7 1d..4 50us : schedule (__cond_resched) + +The interrupt went off while running ksoftirqd. This task runs at +SCHED_OTHER. Why didn't we see the 'N' set early? This may be +a harmless bug with x86_32 and 4K stacks. The need_reched() function +that tests if we need to reschedule looks on the actual stack. +Where as the setting of the NEED_RESCHED bit happens on the +task's stack. But because we are in a hard interrupt, the test +is with the interrupts stack which has that to be false. We don't +see the 'N' until we switch back to the task's stack. + +ftrace +------ + +ftrace is not only the name of the tracing infrastructure, but it +is also a name of one of the tracers. The tracer is the function +tracer. Enabling the function tracer can be done from the +debug file system. Make sure the ftrace_enabled is set otherwise +this tracer is a nop. + + # sysctl kernel.ftrace_enabled=1 + # echo ftrace > /debug/tracing/current_tracer + # echo 1 > /debug/tracing/tracing_enabled + # usleep 1 + # echo 0 > /debug/tracing/tracing_enabled + # cat /debug/tracing/trace +# tracer: ftrace +# +# TASK-PID CPU# TIMESTAMP FUNCTION +# | | | | | + bash-4003 [00] 123.638713: finish_task_switch <-schedule + bash-4003 [00] 123.638714: _spin_unlock_irq <-finish_task_switch + bash-4003 [00] 123.638714: sub_preempt_count <-_spin_unlock_irq + bash-4003 [00] 123.638715: hrtick_set <-schedule + bash-4003 [00] 123.638715: _spin_lock_irqsave <-hrtick_set + bash-4003 [00] 123.638716: add_preempt_count <-_spin_lock_irqsave + bash-4003 [00] 123.638716: _spin_unlock_irqrestore <-hrtick_set + bash-4003 [00] 123.638717: sub_preempt_count <-_spin_unlock_irqrestore + bash-4003 [00] 123.638717: hrtick_clear <-hrtick_set + bash-4003 [00] 123.638718: sub_preempt_count <-schedule + bash-4003 [00] 123.638718: sub_preempt_count <-preempt_schedule + bash-4003 [00] 123.638719: wait_for_completion <-__stop_machine_run + bash-4003 [00] 123.638719: wait_for_common <-wait_for_completion + bash-4003 [00] 123.638720: _spin_lock_irq <-wait_for_common + bash-4003 [00] 123.638720: add_preempt_count <-_spin_lock_irq +[...] + + +Note: It is sometimes better to enable or disable tracing directly from +a program, because the buffer may be overflowed by the echo commands +before you get to the point you want to trace. It is also easier to +stop the tracing at the point that you hit the part that you are +interested in. Since the ftrace buffer is a ring buffer with the +oldest data being overwritten, usually it is sufficient to start the +tracer with an echo command but have you code stop it. Something +like the following is usually appropriate for this. + +int trace_fd; +[...] +int main(int argc, char *argv[]) { + [...] + trace_fd = open("/debug/tracing/tracing_enabled", O_WRONLY); + [...] + if (condition_hit()) { + write(trace_fd, "0", 1); + } + [...] +} + + +dynamic ftrace +-------------- + +If CONFIG_DYNAMIC_FTRACE is set, then the system will run with +virtually no overhead when function tracing is disabled. The way +this works is the mcount function call (placed at the start of +every kernel function, produced by the -pg switch in gcc), starts +of pointing to a simple return. + +When dynamic ftrace is initialized, it calls kstop_machine to make it +act like a uniprocessor so that it can freely modify code without +worrying about other processors executing that same code. At +initialization, the mcount calls are change to call a "record_ip" +function. After this, the first time a kernel function is called, +it has the calling address saved in a hash table. + +Later on the ftraced kernel thread is awoken and will again call +kstop_machine if new functions have been recorded. The ftraced thread +will change all calls to mcount to "nop". Just calling mcount +and having mcount return has shown a 10% overhead. By converting +it to a nop, there is no recordable overhead to the system. + +One special side-effect to the recording of the functions being +traced, is that we can now selectively choose which functions we +want to trace and which ones we want the mcount calls to remain as +nops. + +Two files that contain to the enabling and disabling of recorded +functions are: + + set_ftrace_filter + +and + + set_ftrace_notrace + +A list of available functions that you can add to this files is listed +in: + + available_filter_functions + + # cat /debug/tracing/available_filter_functions +put_prev_task_idle +kmem_cache_create +pick_next_task_rt +get_online_cpus +pick_next_task_fair +mutex_lock +[...] + +If I'm only interested in sys_nanosleep and hrtimer_interrupt: + + # echo sys_nanosleep hrtimer_interrupt \ + > /debug/tracing/set_ftrace_filter + # echo ftrace > /debug/tracing/current_tracer + # echo 1 > /debug/tracing/tracing_enabled + # usleep 1 + # echo 0 > /debug/tracing/tracing_enabled + # cat /debug/tracing/trace +# tracer: ftrace +# +# TASK-PID CPU# TIMESTAMP FUNCTION +# | | | | | + usleep-4134 [00] 1317.070017: hrtimer_interrupt <-smp_apic_timer_interrupt + usleep-4134 [00] 1317.070111: sys_nanosleep <-syscall_call + -0 [00] 1317.070115: hrtimer_interrupt <-smp_apic_timer_interrupt + +To see what functions are being traced, you can cat the file: + + # cat /debug/tracing/set_ftrace_filter +hrtimer_interrupt +sys_nanosleep + + +Perhaps this isn't enough. The filters also allow simple wild cards. +Only the following is currently available + + * - will match functions that begins with + * - will match functions that end with + ** - will match functions that have in it + +Thats all the wild cards that are allowed. + + * will not work. + + # echo hrtimer_* > /debug/tracing/set_ftrace_filter + +Produces: + +# tracer: ftrace +# +# TASK-PID CPU# TIMESTAMP FUNCTION +# | | | | | + bash-4003 [00] 1480.611794: hrtimer_init <-copy_process + bash-4003 [00] 1480.611941: hrtimer_start <-hrtick_set + bash-4003 [00] 1480.611956: hrtimer_cancel <-hrtick_clear + bash-4003 [00] 1480.611956: hrtimer_try_to_cancel <-hrtimer_cancel + -0 [00] 1480.612019: hrtimer_get_next_event <-get_next_timer_interrupt + -0 [00] 1480.612025: hrtimer_get_next_event <-get_next_timer_interrupt + -0 [00] 1480.612032: hrtimer_get_next_event <-get_next_timer_interrupt + -0 [00] 1480.612037: hrtimer_get_next_event <-get_next_timer_interrupt + -0 [00] 1480.612382: hrtimer_get_next_event <-get_next_timer_interrupt + + +Notice that we lost the sys_nanosleep. + + # cat /debug/tracing/set_ftrace_filter +hrtimer_run_queues +hrtimer_run_pending +hrtimer_init +hrtimer_cancel +hrtimer_try_to_cancel +hrtimer_forward +hrtimer_start +hrtimer_reprogram +hrtimer_force_reprogram +hrtimer_get_next_event +hrtimer_interrupt +hrtimer_nanosleep +hrtimer_wakeup +hrtimer_get_remaining +hrtimer_get_res +hrtimer_init_sleeper + + +This is because the '>' and '>>' act just like they do in bash. +To rewrite the filters, use '>' +To append to the filters, use '>>' + +To clear out a filter so that all functions will be recorded again. + + # echo > /debug/tracing/set_ftrace_filter + # cat /debug/tracing/set_ftrace_filter + # + +Again, now we want to append. + + # echo sys_nanosleep > /debug/tracing/set_ftrace_filter + # cat /debug/tracing/set_ftrace_filter +sys_nanosleep + # echo hrtimer_* >> /debug/tracing/set_ftrace_filter + # cat /debug/tracing/set_ftrace_filter +hrtimer_run_queues +hrtimer_run_pending +hrtimer_init +hrtimer_cancel +hrtimer_try_to_cancel +hrtimer_forward +hrtimer_start +hrtimer_reprogram +hrtimer_force_reprogram +hrtimer_get_next_event +hrtimer_interrupt +sys_nanosleep +hrtimer_nanosleep +hrtimer_wakeup +hrtimer_get_remaining +hrtimer_get_res +hrtimer_init_sleeper + + +The set_ftrace_notrace prevents those functions from being traced. + + # echo '*preempt*' '*lock*' > /debug/tracing/set_ftrace_notrace + +Produces: + +# tracer: ftrace +# +# TASK-PID CPU# TIMESTAMP FUNCTION +# | | | | | + bash-4043 [01] 115.281644: finish_task_switch <-schedule + bash-4043 [01] 115.281645: hrtick_set <-schedule + bash-4043 [01] 115.281645: hrtick_clear <-hrtick_set + bash-4043 [01] 115.281646: wait_for_completion <-__stop_machine_run + bash-4043 [01] 115.281647: wait_for_common <-wait_for_completion + bash-4043 [01] 115.281647: kthread_stop <-stop_machine_run + bash-4043 [01] 115.281648: init_waitqueue_head <-kthread_stop + bash-4043 [01] 115.281648: wake_up_process <-kthread_stop + bash-4043 [01] 115.281649: try_to_wake_up <-wake_up_process + +We can see that there's no more lock or preempt tracing. + +ftraced +------- + +As mentioned above, when dynamic ftrace is configured in, a kernel +thread wakes up once a second and checks to see if there are mcount +calls that need to be converted into nops. If there is not, then +it simply goes back to sleep. But if there is, it will call +kstop_machine to convert the calls to nops. + +There may be a case that you do not want this added latency. +Perhaps you are doing some audio recording and this activity might +cause skips in the playback. There is an interface to disable +and enable the ftraced kernel thread. + + # echo 0 > /debug/tracing/ftraced_enabled + +This will disable the calling of the kstop_machine to update the +mcount calls to nops. Remember that there's a large overhead +to calling mcount. Without this kernel thread, that overhead will +exist. + +Any write to the ftraced_enabled file will cause the kstop_machine +to run if there are recorded calls to mcount. This means that a +user can manually perform the updates when they want to by simply +echoing a '0' into the ftraced_enabled file. + +The updates are also done at the beginning of enabling a tracer +that uses ftrace function recording. + + +trace_pipe +---------- + +The trace_pipe outputs the same as trace, but the effect on the +tracing is different. Every read from trace_pipe is consumed. +This means that subsequent reads will be different. The trace +is live. + + # echo ftrace > /debug/tracing/current_tracer + # cat /debug/tracing/trace_pipe > /tmp/trace.out & +[1] 4153 + # echo 1 > /debug/tracing/tracing_enabled + # usleep 1 + # echo 0 > /debug/tracing/tracing_enabled + # cat /debug/tracing/trace +# tracer: ftrace +# +# TASK-PID CPU# TIMESTAMP FUNCTION +# | | | | | + + # + # cat /tmp/trace.out + bash-4043 [00] 41.267106: finish_task_switch <-schedule + bash-4043 [00] 41.267106: hrtick_set <-schedule + bash-4043 [00] 41.267107: hrtick_clear <-hrtick_set + bash-4043 [00] 41.267108: wait_for_completion <-__stop_machine_run + bash-4043 [00] 41.267108: wait_for_common <-wait_for_completion + bash-4043 [00] 41.267109: kthread_stop <-stop_machine_run + bash-4043 [00] 41.267109: init_waitqueue_head <-kthread_stop + bash-4043 [00] 41.267110: wake_up_process <-kthread_stop + bash-4043 [00] 41.267110: try_to_wake_up <-wake_up_process + bash-4043 [00] 41.267111: select_task_rq_rt <-try_to_wake_up + + +Note, reading the trace_pipe will block until more input is added. +By changing the tracer, trace_pipe will issue an EOF. We needed +to set the ftrace tracer _before_ cating the trace_pipe file. + + +trace entries +------------- + +Having too much or not enough data can be troublesome in diagnosing +some issue in the kernel. The file trace_entries is used to modify +the size of the internal trace buffers. The numbers listed +is the number of entries that can be recorded per CPU. To know +the full size, multiply the number of possible CPUS with the +number of entries. + + # cat /debug/tracing/trace_entries +65620 + +Note, to modify this you must have tracing fulling disabled. To do that, +echo "none" into the current_tracer. + + # echo none > /debug/tracing/current_tracer + # echo 100000 > /debug/tracing/trace_entries + # cat /debug/tracing/trace_entries +100045 + + +Notice that we echoed in 100,000 but the size is 100,045. The entries +are held by individual pages. It allocates the number of pages it takes +to fulfill the request. If more entries may fit on the last page +it will add them. + + # echo 1 > /debug/tracing/trace_entries + # cat /debug/tracing/trace_entries +85 + +This shows us that 85 entries can fit on a single page. + +The number of pages that will be allocated is a percentage of available +memory. Allocating too much will produces an error. + + # echo 1000000000000 > /debug/tracing/trace_entries +-bash: echo: write error: Cannot allocate memory + # cat /debug/tracing/trace_entries +85 + -- cgit v1.2.3 From 53025f5efd5a1c14fca75c479b11d97d9dd958a5 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Thu, 10 Jul 2008 16:47:41 -0700 Subject: Documentation: clarify tcp_{r,w}mem sysctl docs Fix some of the defaults and attempt to clarify some language. Signed-off-by: J. Bruce Fields Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.txt | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) (limited to 'Documentation') diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 277437951e4d..dc04fdd6af34 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -336,7 +336,7 @@ tcp_rmem - vector of 3 INTEGERs: min, default, max pressure. Default: 8K - default: default size of receive buffer used by TCP sockets. + default: initial size of receive buffer used by TCP sockets. This value overrides net.core.rmem_default used by other protocols. Default: 87380 bytes. This value results in window of 65535 with default setting of tcp_adv_win_scale and tcp_app_win:0 and a bit @@ -344,8 +344,10 @@ tcp_rmem - vector of 3 INTEGERs: min, default, max max: maximal size of receive buffer allowed for automatically selected receiver buffers for TCP socket. This value does not override - net.core.rmem_max, "static" selection via SO_RCVBUF does not use this. - Default: 87380*2 bytes. + net.core.rmem_max. Calling setsockopt() with SO_RCVBUF disables + automatic tuning of that socket's receive buffer size, in which + case this value is ignored. + Default: between 87380B and 4MB, depending on RAM size. tcp_sack - BOOLEAN Enable select acknowledgments (SACKS). @@ -419,19 +421,21 @@ tcp_window_scaling - BOOLEAN Enable window scaling as defined in RFC1323. tcp_wmem - vector of 3 INTEGERs: min, default, max - min: Amount of memory reserved for send buffers for TCP socket. + min: Amount of memory reserved for send buffers for TCP sockets. Each TCP socket has rights to use it due to fact of its birth. Default: 4K - default: Amount of memory allowed for send buffers for TCP socket - by default. This value overrides net.core.wmem_default used - by other protocols, it is usually lower than net.core.wmem_default. + default: initial size of send buffer used by TCP sockets. This + value overrides net.core.wmem_default used by other protocols. + It is usually lower than net.core.wmem_default. Default: 16K - max: Maximal amount of memory allowed for automatically selected - send buffers for TCP socket. This value does not override - net.core.wmem_max, "static" selection via SO_SNDBUF does not use this. - Default: 128K + max: Maximal amount of memory allowed for automatically tuned + send buffers for TCP sockets. This value does not override + net.core.wmem_max. Calling setsockopt() with SO_SNDBUF disables + automatic tuning of that socket's send buffer size, in which case + this value is ignored. + Default: between 64K and 4MB, depending on RAM size. tcp_workaround_signed_windows - BOOLEAN If set, assume no receipt of a window scaling option means the -- cgit v1.2.3 From 4edc2f3416438a05b83a677ae7b1a78b3ca22bb9 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Thu, 10 Jul 2008 16:50:26 -0700 Subject: ip: sysctl documentation cleanup Reduced version of the spelling cleanup patch. Take out the confusing language in tcp_frto, and organize the undocumented values. Signed-off-by: Stephen Hemminger Acked-by: Randy Dunlap Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.txt | 60 ++++++++++++++++------------------ 1 file changed, 29 insertions(+), 31 deletions(-) (limited to 'Documentation') diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index dc04fdd6af34..946b66e1b652 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -148,9 +148,9 @@ tcp_available_congestion_control - STRING but not loaded. tcp_base_mss - INTEGER - The initial value of search_low to be used by Packetization Layer - Path MTU Discovery (MTU probing). If MTU probing is enabled, - this is the inital MSS used by the connection. + The initial value of search_low to be used by the packetization layer + Path MTU discovery (MTU probing). If MTU probing is enabled, + this is the initial MSS used by the connection. tcp_congestion_control - STRING Set the congestion control algorithm to be used for new @@ -185,10 +185,9 @@ tcp_frto - INTEGER timeouts. It is particularly beneficial in wireless environments where packet loss is typically due to random radio interference rather than intermediate router congestion. F-RTO is sender-side - only modification. Therefore it does not require any support from - the peer, but in a typical case, however, where wireless link is - the local access link and most of the data flows downlink, the - faraway servers should have F-RTO enabled to take advantage of it. + only modification. Therefore it does not require any support from + the peer. + If set to 1, basic version is enabled. 2 enables SACK enhanced F-RTO if flow uses SACK. The basic version can be used also when SACK is in use though scenario(s) with it exists where F-RTO @@ -276,7 +275,7 @@ tcp_mem - vector of 3 INTEGERs: min, pressure, max memory. tcp_moderate_rcvbuf - BOOLEAN - If set, TCP performs receive buffer autotuning, attempting to + If set, TCP performs receive buffer auto-tuning, attempting to automatically size the buffer (no greater than tcp_rmem[2]) to match the size required by the path for full throughput. Enabled by default. @@ -360,7 +359,7 @@ tcp_slow_start_after_idle - BOOLEAN Default: 1 tcp_stdurg - BOOLEAN - Use the Host requirements interpretation of the TCP urg pointer field. + Use the Host requirements interpretation of the TCP urgent pointer field. Most hosts use the older BSD interpretation, so if you turn this on Linux might not communicate correctly with them. Default: FALSE @@ -373,12 +372,12 @@ tcp_synack_retries - INTEGER tcp_syncookies - BOOLEAN Only valid when the kernel was compiled with CONFIG_SYNCOOKIES Send out syncookies when the syn backlog queue of a socket - overflows. This is to prevent against the common 'syn flood attack' + overflows. This is to prevent against the common 'SYN flood attack' Default: FALSE Note, that syncookies is fallback facility. It MUST NOT be used to help highly loaded servers to stand - against legal connection rate. If you see synflood warnings + against legal connection rate. If you see SYN flood warnings in your logs, but investigation shows that they occur because of overload with legal connections, you should tune another parameters until this warning disappear. @@ -388,7 +387,7 @@ tcp_syncookies - BOOLEAN to use TCP extensions, can result in serious degradation of some services (f.e. SMTP relaying), visible not by you, but your clients and relays, contacting you. While you see - synflood warnings in logs not being really flooded, your server + SYN flood warnings in logs not being really flooded, your server is seriously misconfigured. tcp_syn_retries - INTEGER @@ -1236,22 +1235,21 @@ sctp_wmem - vector of 3 INTEGERs: min, default, max UNDOCUMENTED: -dev_weight FIXME -discovery_slots FIXME -discovery_timeout FIXME -fast_poll_increase FIXME -ip6_queue_maxlen FIXME -lap_keepalive_time FIXME -lo_cong FIXME -max_baud_rate FIXME -max_dgram_qlen FIXME -max_noreply_time FIXME -max_tx_data_size FIXME -max_tx_window FIXME -min_tx_turn_time FIXME -mod_cong FIXME -no_cong FIXME -no_cong_thresh FIXME -slot_timeout FIXME -warn_noreply_time FIXME - +/proc/sys/net/core/* + dev_weight FIXME + +/proc/sys/net/unix/* + max_dgram_qlen FIXME + +/proc/sys/net/irda/* + fast_poll_increase FIXME + warn_noreply_time FIXME + discovery_slots FIXME + slot_timeout FIXME + max_baud_rate FIXME + discovery_timeout FIXME + lap_keepalive_time FIXME + max_noreply_time FIXME + max_tx_data_size FIXME + max_tx_window FIXME + min_tx_turn_time FIXME -- cgit v1.2.3 From 93e3270c87549dc531a0b0e5d06362d998d810cb Mon Sep 17 00:00:00 2001 From: "Jose R. Santos" Date: Fri, 11 Jul 2008 19:27:31 -0400 Subject: ext4: Documentation updates. Some of the information in Documentation/filesystems/ext4.txt is out of date and in need of an update. Signed-off-by: Jose R. Santos Signed-off-by: "Theodore Ts'o" --- Documentation/filesystems/ext4.txt | 106 ++++++++++++++++++++++--------------- 1 file changed, 62 insertions(+), 44 deletions(-) (limited to 'Documentation') diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index 0c5086db8352..7e940c64be47 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt @@ -13,72 +13,89 @@ Mailing list: linux-ext4@vger.kernel.org 1. Quick usage instructions: =========================== - - Grab updated e2fsprogs from - ftp://ftp.kernel.org/pub/linux/kernel/people/tytso/e2fsprogs-interim/ - This is a patchset on top of e2fsprogs-1.39, which can be found at + - Compile and install the latest version of e2fsprogs (as of this + writing version 1.41) from: + + http://sourceforge.net/project/showfiles.php?group_id=2406 + + or + ftp://ftp.kernel.org/pub/linux/kernel/people/tytso/e2fsprogs/ - - It's still mke2fs -j /dev/hda1 + or grab the latest git repository from: + + git://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git + + - Create a new filesystem using the ext4dev filesystem type: + + # mke2fs -t ext4dev /dev/hda1 + + Or configure an existing ext3 filesystem to support extents and set + the test_fs flag to indicate that it's ok for an in-development + filesystem to touch this filesystem: - - mount /dev/hda1 /wherever -t ext4dev + # tune2fs -O extents -E test_fs /dev/hda1 - - To enable extents, + If the filesystem was created with 128 byte inodes, it can be + converted to use 256 byte for greater efficiency via: - mount /dev/hda1 /wherever -t ext4dev -o extents + # tune2fs -I 256 /dev/hda1 - - The filesystem is compatible with the ext3 driver until you add a file - which has extents (ie: `mount -o extents', then create a file). + (Note: we currently do not have tools to convert an ext4dev + filesystem back to ext3; so please do not do try this on production + filesystems.) - NOTE: The "extents" mount flag is temporary. It will soon go away and - extents will be enabled by the "-o extents" flag to mke2fs or tune2fs + - Mounting: + + # mount -t ext4dev /dev/hda1 /wherever - When comparing performance with other filesystems, remember that - ext3/4 by default offers higher data integrity guarantees than most. So - when comparing with a metadata-only journalling filesystem, use `mount -o - data=writeback'. And you might as well use `mount -o nobh' too along - with it. Making the journal larger than the mke2fs default often helps - performance with metadata-intensive workloads. + ext3/4 by default offers higher data integrity guarantees than most. + So when comparing with a metadata-only journalling filesystem, such + as ext3, use `mount -o data=writeback'. And you might as well use + `mount -o nobh' too along with it. Making the journal larger than + the mke2fs default often helps performance with metadata-intensive + workloads. 2. Features =========== 2.1 Currently available -* ability to use filesystems > 16TB +* ability to use filesystems > 16TB (e2fsprogs support not available yet) * extent format reduces metadata overhead (RAM, IO for access, transactions) * extent format more robust in face of on-disk corruption due to magics, * internal redunancy in tree - -2.1 Previously available, soon to be enabled by default by "mkefs.ext4": - -* dir_index and resize inode will be on by default -* large inodes will be used by default for fast EAs, nsec timestamps, etc +* improved file allocation (multi-block alloc, delayed alloc) +* fix 32000 subdirectory limit +* nsec timestamps for mtime, atime, ctime, create time +* inode version field on disk (NFSv4, Lustre) +* reduced e2fsck time via uninit_bg feature +* journal checksumming for robustness, performance +* persistent file preallocation (e.g for streaming media, databases) +* ability to pack bitmaps and inode tables into larger virtual groups via the + flex_bg feature +* large file support +* Inode allocation using large virtual block groups via flex_bg 2.2 Candidate features for future inclusion -There are several under discussion, whether they all make it in is -partly a function of how much time everyone has to work on them: +* Online defrag (patches available but not well tested) +* reduced mke2fs time via lazy itable initialization in conjuction with + the uninit_bg feature (capability to do this is available in e2fsprogs + but a kernel thread to do lazy zeroing of unused inode table blocks + after filesystem is first mounted is required for safety) -* improved file allocation (multi-block alloc, delayed alloc; basically done) -* fix 32000 subdirectory limit (patch exists, needs some e2fsck work) -* nsec timestamps for mtime, atime, ctime, create time (patch exists, - needs some e2fsck work) -* inode version field on disk (NFSv4, Lustre; prototype exists) -* reduced mke2fs/e2fsck time via uninitialized groups (prototype exists) -* journal checksumming for robustness, performance (prototype exists) -* persistent file preallocation (e.g for streaming media, databases) +There are several others under discussion, whether they all make it in is +partly a function of how much time everyone has to work on them. Features like +metadata checksumming have been discussed and planned for a bit but no patches +exist yet so I'm not sure they're in the near-term roadmap. -Features like metadata checksumming have been discussed and planned for -a bit but no patches exist yet so I'm not sure they're in the near-term -roadmap. +The big performance win will come with mballoc, delalloc and flex_bg +grouping of bitmaps and inode tables. Some test results available here: -The big performance win will come with mballoc and delalloc. CFS has -been using mballoc for a few years already with Lustre, and IBM + Bull -did a lot of benchmarking on it. The reason it isn't in the first set of -patches is partly a manageability issue, and partly because it doesn't -directly affect the on-disk format (outside of much better allocation) -so it isn't critical to get into the first round of changes. I believe -Alex is working on a new set of patches right now. + - http://www.bullopensource.org/ext4/20080530/ffsb-write-2.6.26-rc2.html + - http://www.bullopensource.org/ext4/20080530/ffsb-readwrite-2.6.26-rc2.html 3. Options ========== @@ -224,7 +241,7 @@ stripe=n Number of filesystem blocks that mballoc will try disks * RAID chunk size in file system blocks. Data Mode ---------- +========= There are 3 different data modes: * writeback mode @@ -256,7 +273,8 @@ kernel source: programs: http://e2fsprogs.sourceforge.net/ - http://ext2resize.sourceforge.net useful links: http://fedoraproject.org/wiki/ext3-devel http://www.bullopensource.org/ext4/ + http://ext4.wiki.kernel.org/index.php/Main_Page + http://fedoraproject.org/wiki/Features/Ext4 -- cgit v1.2.3 From 49f1487b2e41bd8439ea39a4f15b4064e823cc54 Mon Sep 17 00:00:00 2001 From: Mingming Cao Date: Fri, 11 Jul 2008 19:27:31 -0400 Subject: ext4: Documention update for new ordered mode and delayed allocation Adding some documentations for delayed allocation and new ordered mode. Signed-off-by: Mingming Cao Signed-off-by: "Theodore Ts'o" --- Documentation/filesystems/ext4.txt | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) (limited to 'Documentation') diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index 7e940c64be47..80e193d82e2e 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt @@ -66,7 +66,7 @@ Mailing list: linux-ext4@vger.kernel.org * extent format reduces metadata overhead (RAM, IO for access, transactions) * extent format more robust in face of on-disk corruption due to magics, * internal redunancy in tree -* improved file allocation (multi-block alloc, delayed alloc) +* improved file allocation (multi-block alloc) * fix 32000 subdirectory limit * nsec timestamps for mtime, atime, ctime, create time * inode version field on disk (NFSv4, Lustre) @@ -77,6 +77,10 @@ Mailing list: linux-ext4@vger.kernel.org flex_bg feature * large file support * Inode allocation using large virtual block groups via flex_bg +* delayed allocation +* large block (up to pagesize) support +* efficent new ordered mode in JBD2 and ext4(avoid using buffer head to force + the ordering) 2.2 Candidate features for future inclusion @@ -239,7 +243,9 @@ stripe=n Number of filesystem blocks that mballoc will try to use for allocation size and alignment. For RAID5/6 systems this should be the number of data disks * RAID chunk size in file system blocks. - +delalloc (*) Deferring block allocation until write-out time. +nodelalloc Disable delayed allocation. Blocks are allocation + when data is copied from user to page cache. Data Mode ========= There are 3 different data modes: @@ -253,10 +259,10 @@ typically provide the best ext4 performance. * ordered mode In data=ordered mode, ext4 only officially journals metadata, but it logically -groups metadata and data blocks into a single unit called a transaction. When -it's time to write the new metadata out to disk, the associated data blocks -are written first. In general, this mode performs slightly slower than -writeback but significantly faster than journal mode. +groups metadata information related to data changes with the data blocks into a +single unit called a transaction. When it's time to write the new metadata +out to disk, the associated data blocks are written first. In general, +this mode performs slightly slower than writeback but significantly faster than journal mode. * journal mode data=journal mode provides full data and metadata journaling. All new data is @@ -264,7 +270,8 @@ written to the journal first, and then to its final location. In the event of a crash, the journal can be replayed, bringing both data and metadata into a consistent state. This mode is the slowest except when data needs to be read from and written to disk at the same time where it -outperforms all others modes. +outperforms all others modes. Curently ext4 does not have delayed +allocation support if this data journalling mode is selected. References ========== -- cgit v1.2.3 From de32a2434f7ce4600da90ecb44abcdc365ada1d0 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sat, 12 Jul 2008 05:33:30 +0200 Subject: kernel-paramaters: document pmtmr= command line option Signed-off-by: Thomas Gleixner --- Documentation/kernel-parameters.txt | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index e07c432c731f..356b64ba706a 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1571,6 +1571,10 @@ and is between 256 and 4096 characters. It is defined in the file Format: { parport | timid | 0 } See also Documentation/parport.txt. + pmtmr= [X86] Manual setup of pmtmr I/O Port. + Override pmtimer IOPort with a hex value. + e.g. pmtmr=0x508 + pnpacpi= [ACPI] { off } -- cgit v1.2.3 From 0302c01b4b793cfbc5c7bf8723f6d14bf9bd7cf4 Mon Sep 17 00:00:00 2001 From: Jiri Pirko Date: Sun, 13 Jul 2008 12:13:59 -0700 Subject: Documentation/HOWTO: correct wrong kernel bugzilla FAQ URL Signed-off-by: Jiri Pirko Cc: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/HOWTO | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/HOWTO b/Documentation/HOWTO index 0291ade44c17..619e8caf30db 100644 --- a/Documentation/HOWTO +++ b/Documentation/HOWTO @@ -377,7 +377,7 @@ Bug Reporting bugzilla.kernel.org is where the Linux kernel developers track kernel bugs. Users are encouraged to report all bugs that they find in this tool. For details on how to use the kernel bugzilla, please see: - http://test.kernel.org/bugzilla/faq.html + http://bugzilla.kernel.org/page.cgi?id=faq.html The file REPORTING-BUGS in the main kernel source directory has a good template for how to report a possible kernel bug, and details what kind -- cgit v1.2.3 From 7e9db9eaefdb8798730790214ff1b7746006ec98 Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Mon, 14 Jul 2008 09:58:44 +0200 Subject: [S390] cio: Introduce modalias for css bus. Add modalias and subchannel type attributes for all subchannels. I/O subchannel specific attributes are now created in io_subchannel_probe(). modalias and subchannel type are also added to the uevent for the css bus. Also make the css modalias known. Signed-off-by: Cornelia Huck Signed-off-by: Martin Schwidefsky Signed-off-by: Heiko Carstens --- Documentation/ABI/testing/sysfs-bus-css | 35 +++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-bus-css (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-bus-css b/Documentation/ABI/testing/sysfs-bus-css new file mode 100644 index 000000000000..b585ec258a08 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-css @@ -0,0 +1,35 @@ +What: /sys/bus/css/devices/.../type +Date: March 2008 +Contact: Cornelia Huck + linux-s390@vger.kernel.org +Description: Contains the subchannel type, as reported by the hardware. + This attribute is present for all subchannel types. + +What: /sys/bus/css/devices/.../modalias +Date: March 2008 +Contact: Cornelia Huck + linux-s390@vger.kernel.org +Description: Contains the module alias as reported with uevents. + It is of the format css:t and present for all + subchannel types. + +What: /sys/bus/css/drivers/io_subchannel/.../chpids +Date: December 2002 +Contact: Cornelia Huck + linux-s390@vger.kernel.org +Description: Contains the ids of the channel paths used by this + subchannel, as reported by the channel subsystem + during subchannel recognition. + Note: This is an I/O-subchannel specific attribute. +Users: s390-tools, HAL + +What: /sys/bus/css/drivers/io_subchannel/.../pimpampom +Date: December 2002 +Contact: Cornelia Huck + linux-s390@vger.kernel.org +Description: Contains the PIM/PAM/POM values, as reported by the + channel subsystem when last queried by the common I/O + layer (this implies that this attribute is not neccessarily + in sync with the values current in the channel subsystem). + Note: This is an I/O-subchannel specific attribute. +Users: s390-tools, HAL -- cgit v1.2.3 From 9d92a7e1b0d095c8be96ce5e592c6c5541684631 Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Mon, 14 Jul 2008 09:59:05 +0200 Subject: [S390] cio: Add chsc subchannel driver. This patch adds a driver for subchannels of type chsc. A device /dev/chsc is created which may be used to issue ioctls to: - obtain information about the machine's I/O configuration - dynamically change the machine's I/O configuration via asynchronous chsc commands Signed-off-by: Cornelia Huck Signed-off-by: Martin Schwidefsky Signed-off-by: Heiko Carstens --- Documentation/ioctl-number.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation') diff --git a/Documentation/ioctl-number.txt b/Documentation/ioctl-number.txt index 240ce7a56c40..3bb5f466a90d 100644 --- a/Documentation/ioctl-number.txt +++ b/Documentation/ioctl-number.txt @@ -117,6 +117,7 @@ Code Seq# Include File Comments 'c' 00-7F linux/comstats.h conflict! 'c' 00-7F linux/coda.h conflict! +'c' 80-9F asm-s390/chsc.h 'd' 00-FF linux/char/drm/drm/h conflict! 'd' 00-DF linux/video_decoder.h conflict! 'd' F0-FF linux/digi1.h -- cgit v1.2.3 From 20a9b6e7c303f2a6f9afe17c0997bc9a3c734442 Mon Sep 17 00:00:00 2001 From: Adrian Bunk Date: Mon, 14 Jul 2008 22:38:22 +0200 Subject: i2c: Remove 3 deprecated bus drivers This patch contains the scheduled removal of i2c-i810, i2c-prosavage and i2c-savage4. Signed-off-by: Adrian Bunk Signed-off-by: Jean Delvare --- Documentation/feature-removal-schedule.txt | 7 ----- Documentation/i2c/busses/i2c-i810 | 47 ------------------------------ Documentation/i2c/busses/i2c-prosavage | 23 --------------- Documentation/i2c/busses/i2c-savage4 | 26 ----------------- 4 files changed, 103 deletions(-) delete mode 100644 Documentation/i2c/busses/i2c-i810 delete mode 100644 Documentation/i2c/busses/i2c-prosavage delete mode 100644 Documentation/i2c/busses/i2c-savage4 (limited to 'Documentation') diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 46ece3fba6f9..65a1482457a8 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -222,13 +222,6 @@ Who: Thomas Gleixner --------------------------- -What: i2c-i810, i2c-prosavage and i2c-savage4 -When: May 2008 -Why: These drivers are superseded by i810fb, intelfb and savagefb. -Who: Jean Delvare - ---------------------------- - What (Why): - include/linux/netfilter_ipv4/ipt_TOS.h ipt_tos.h header files (superseded by xt_TOS/xt_tos target & match) diff --git a/Documentation/i2c/busses/i2c-i810 b/Documentation/i2c/busses/i2c-i810 deleted file mode 100644 index 778210ee1583..000000000000 --- a/Documentation/i2c/busses/i2c-i810 +++ /dev/null @@ -1,47 +0,0 @@ -Kernel driver i2c-i810 - -Supported adapters: - * Intel 82810, 82810-DC100, 82810E, and 82815 (GMCH) - * Intel 82845G (GMCH) - -Authors: - Frodo Looijaard , - Philip Edelbrock , - Kyösti Mälkki , - Ralph Metzler , - Mark D. Studebaker - -Main contact: Mark Studebaker - -Description ------------ - -WARNING: If you have an '810' or '815' motherboard, your standard I2C -temperature sensors are most likely on the 801's I2C bus. You want the -i2c-i801 driver for those, not this driver. - -Now for the i2c-i810... - -The GMCH chip contains two I2C interfaces. - -The first interface is used for DDC (Data Display Channel) which is a -serial channel through the VGA monitor connector to a DDC-compliant -monitor. This interface is defined by the Video Electronics Standards -Association (VESA). The standards are available for purchase at -http://www.vesa.org . - -The second interface is a general-purpose I2C bus. It may be connected to a -TV-out chip such as the BT869 or possibly to a digital flat-panel display. - -Features --------- - -Both busses use the i2c-algo-bit driver for 'bit banging' -and support for specific transactions is provided by i2c-algo-bit. - -Issues ------- - -If you enable bus testing in i2c-algo-bit (insmod i2c-algo-bit bit_test=1), -the test may fail; if so, the i2c-i810 driver won't be inserted. However, -we think this has been fixed. diff --git a/Documentation/i2c/busses/i2c-prosavage b/Documentation/i2c/busses/i2c-prosavage deleted file mode 100644 index 703687902511..000000000000 --- a/Documentation/i2c/busses/i2c-prosavage +++ /dev/null @@ -1,23 +0,0 @@ -Kernel driver i2c-prosavage - -Supported adapters: - - S3/VIA KM266/VT8375 aka ProSavage8 - S3/VIA KM133/VT8365 aka Savage4 - -Author: Henk Vergonet - -Description ------------ - -The Savage4 chips contain two I2C interfaces (aka a I2C 'master' or -'host'). - -The first interface is used for DDC (Data Display Channel) which is a -serial channel through the VGA monitor connector to a DDC-compliant -monitor. This interface is defined by the Video Electronics Standards -Association (VESA). The standards are available for purchase at -http://www.vesa.org . The second interface is a general-purpose I2C bus. - -Usefull for gaining access to the TV Encoder chips. - diff --git a/Documentation/i2c/busses/i2c-savage4 b/Documentation/i2c/busses/i2c-savage4 deleted file mode 100644 index 6ecceab618d3..000000000000 --- a/Documentation/i2c/busses/i2c-savage4 +++ /dev/null @@ -1,26 +0,0 @@ -Kernel driver i2c-savage4 - -Supported adapters: - * Savage4 - * Savage2000 - -Authors: - Alexander Wold , - Mark D. Studebaker - -Description ------------ - -The Savage4 chips contain two I2C interfaces (aka a I2C 'master' -or 'host'). - -The first interface is used for DDC (Data Display Channel) which is a -serial channel through the VGA monitor connector to a DDC-compliant -monitor. This interface is defined by the Video Electronics Standards -Association (VESA). The standards are available for purchase at -http://www.vesa.org . The DDC bus is not yet supported because its register -is not directly memory-mapped. - -The second interface is a general-purpose I2C bus. This is the only -interface supported by the driver at the moment. - -- cgit v1.2.3 From 81fded1f79771809059bdfa721ae5ab9114af545 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Mon, 14 Jul 2008 22:38:22 +0200 Subject: i2c: Document standard fault codes Create Documentation/i2c/fault-codes to help standardize fault/error code usage in the I2C stack. It turns out that returning -1 (-EPERM) for everything was not at all helpful. Signed-off-by: David Brownell Signed-off-by: Jean Delvare --- Documentation/i2c/fault-codes | 127 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 127 insertions(+) create mode 100644 Documentation/i2c/fault-codes (limited to 'Documentation') diff --git a/Documentation/i2c/fault-codes b/Documentation/i2c/fault-codes new file mode 100644 index 000000000000..045765c0b9b5 --- /dev/null +++ b/Documentation/i2c/fault-codes @@ -0,0 +1,127 @@ +This is a summary of the most important conventions for use of fault +codes in the I2C/SMBus stack. + + +A "Fault" is not always an "Error" +---------------------------------- +Not all fault reports imply errors; "page faults" should be a familiar +example. Software often retries idempotent operations after transient +faults. There may be fancier recovery schemes that are appropriate in +some cases, such as re-initializing (and maybe resetting). After such +recovery, triggered by a fault report, there is no error. + +In a similar way, sometimes a "fault" code just reports one defined +result for an operation ... it doesn't indicate that anything is wrong +at all, just that the outcome wasn't on the "golden path". + +In short, your I2C driver code may need to know these codes in order +to respond correctly. Other code may need to rely on YOUR code reporting +the right fault code, so that it can (in turn) behave correctly. + + +I2C and SMBus fault codes +------------------------- +These are returned as negative numbers from most calls, with zero or +some positive number indicating a non-fault return. The specific +numbers associated with these symbols differ between architectures, +though most Linux systems use numbering. + +Note that the descriptions here are not exhaustive. There are other +codes that may be returned, and other cases where these codes should +be returned. However, drivers should not return other codes for these +cases (unless the hardware doesn't provide unique fault reports). + +Also, codes returned by adapter probe methods follow rules which are +specific to their host bus (such as PCI, or the platform bus). + + +EAGAIN + Returned by I2C adapters when they lose arbitration in master + transmit mode: some other master was transmitting different + data at the same time. + + Also returned when trying to invoke an I2C operation in an + atomic context, when some task is already using that I2C bus + to execute some other operation. + +EBADMSG + Returned by SMBus logic when an invalid Packet Error Code byte + is received. This code is a CRC covering all bytes in the + transaction, and is sent before the terminating STOP. This + fault is only reported on read transactions; the SMBus slave + may have a way to report PEC mismatches on writes from the + host. Note that even if PECs are in use, you should not rely + on these as the only way to detect incorrect data transfers. + +EBUSY + Returned by SMBus adapters when the bus was busy for longer + than allowed. This usually indicates some device (maybe the + SMBus adapter) needs some fault recovery (such as resetting), + or that the reset was attempted but failed. + +EINVAL + This rather vague error means an invalid parameter has been + detected before any I/O operation was started. Use a more + specific fault code when you can. + + One example would be a driver trying an SMBus Block Write + with block size outside the range of 1-32 bytes. + +EIO + This rather vague error means something went wrong when + performing an I/O operation. Use a more specific fault + code when you can. + +ENODEV + Returned by driver probe() methods. This is a bit more + specific than ENXIO, implying the problem isn't with the + address, but with the device found there. Driver probes + may verify the device returns *correct* responses, and + return this as appropriate. (The driver core will warn + about probe faults other than ENXIO and ENODEV.) + +ENOMEM + Returned by any component that can't allocate memory when + it needs to do so. + +ENXIO + Returned by I2C adapters to indicate that the address phase + of a transfer didn't get an ACK. While it might just mean + an I2C device was temporarily not responding, usually it + means there's nothing listening at that address. + + Returned by driver probe() methods to indicate that they + found no device to bind to. (ENODEV may also be used.) + +EOPNOTSUPP + Returned by an adapter when asked to perform an operation + that it doesn't, or can't, support. + + For example, this would be returned when an adapter that + doesn't support SMBus block transfers is asked to execute + one. In that case, the driver making that request should + have verified that functionality was supported before it + made that block transfer request. + + Similarly, if an I2C adapter can't execute all legal I2C + messages, it should return this when asked to perform a + transaction it can't. (These limitations can't be seen in + the adapter's functionality mask, since the assumption is + that if an adapter supports I2C it supports all of I2C.) + +EPROTO + Returned when slave does not conform to the relevant I2C + or SMBus (or chip-specific) protocol specifications. One + case is when the length of an SMBus block data response + (from the SMBus slave) is outside the range 1-32 bytes. + +ETIMEDOUT + This is returned by drivers when an operation took too much + time, and was aborted before it completed. + + SMBus adapters may return it when an operation took more + time than allowed by the SMBus specification; for example, + when a slave stretches clocks too far. I2C has no such + timeouts, but it's normal for I2C adapters to impose some + arbitrary limits (much longer than SMBus!) too. + -- cgit v1.2.3 From 24a5bb7b1838dc4524dd353224e2aa09c22cac3b Mon Sep 17 00:00:00 2001 From: David Brownell Date: Mon, 14 Jul 2008 22:38:23 +0200 Subject: i2c-core: Return -Errno, not -1 More updates to the I2C stack's fault reporting: make the core stop returning "-1" (usually "-EPERM") for all faults. Instead, pass lower level fault code up the stack, or return some appropriate errno. This patch happens to touch almost exclusively SMBus calls. Signed-off-by: David Brownell Signed-off-by: Jean Delvare --- Documentation/i2c/writing-clients | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients index d4cd4126d1ad..ba5d1971f35f 100644 --- a/Documentation/i2c/writing-clients +++ b/Documentation/i2c/writing-clients @@ -598,10 +598,10 @@ be added back later if needed: u8 command, u8 length, u8 *values) -All these transactions return -1 on failure. The 'write' transactions -return 0 on success; the 'read' transactions return the read value, except -for read_block, which returns the number of values read. The block buffers -need not be longer than 32 bytes. +All these transactions return a negative errno value on failure. The 'write' +transactions return 0 on success; the 'read' transactions return the read +value, except for block transactions, which return the number of values +read. The block buffers need not be longer than 32 bytes. You can read the file `smbus-protocol' for more information about the actual SMBus protocol. -- cgit v1.2.3 From 67c2e66571c383404a5acd08189194da660da942 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Mon, 14 Jul 2008 22:38:23 +0200 Subject: i2c: Delete unused function i2c_smbus_write_quick Function i2c_smbus_write_quick has no users left, so we can delete it. Also update the list of these helper functions which are gone but could be added back if needed. Signed-off-by: Jean Delvare --- Documentation/i2c/smbus-protocol | 4 ++-- Documentation/i2c/writing-clients | 14 +++++++------- 2 files changed, 9 insertions(+), 9 deletions(-) (limited to 'Documentation') diff --git a/Documentation/i2c/smbus-protocol b/Documentation/i2c/smbus-protocol index 03f08fb491cc..24bfb65da17d 100644 --- a/Documentation/i2c/smbus-protocol +++ b/Documentation/i2c/smbus-protocol @@ -42,8 +42,8 @@ Count (8 bits): A data byte containing the length of a block operation. [..]: Data sent by I2C device, as opposed to data sent by the host adapter. -SMBus Quick Command: i2c_smbus_write_quick() -============================================= +SMBus Quick Command +=================== This sends a single bit to the device, at the place of the Rd/Wr bit. diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients index ba5d1971f35f..63722d3c9cdf 100644 --- a/Documentation/i2c/writing-clients +++ b/Documentation/i2c/writing-clients @@ -569,7 +569,6 @@ SMBus communication in terms of it. Never use this function directly! - extern s32 i2c_smbus_write_quick(struct i2c_client * client, u8 value); extern s32 i2c_smbus_read_byte(struct i2c_client * client); extern s32 i2c_smbus_write_byte(struct i2c_client * client, u8 value); extern s32 i2c_smbus_read_byte_data(struct i2c_client * client, u8 command); @@ -578,20 +577,21 @@ SMBus communication extern s32 i2c_smbus_read_word_data(struct i2c_client * client, u8 command); extern s32 i2c_smbus_write_word_data(struct i2c_client * client, u8 command, u16 value); + extern s32 i2c_smbus_read_block_data(struct i2c_client * client, + u8 command, u8 *values); extern s32 i2c_smbus_write_block_data(struct i2c_client * client, u8 command, u8 length, u8 *values); extern s32 i2c_smbus_read_i2c_block_data(struct i2c_client * client, u8 command, u8 length, u8 *values); - -These ones were removed in Linux 2.6.10 because they had no users, but could -be added back later if needed: - - extern s32 i2c_smbus_read_block_data(struct i2c_client * client, - u8 command, u8 *values); extern s32 i2c_smbus_write_i2c_block_data(struct i2c_client * client, u8 command, u8 length, u8 *values); + +These ones were removed from i2c-core because they had no users, but could +be added back later if needed: + + extern s32 i2c_smbus_write_quick(struct i2c_client * client, u8 value); extern s32 i2c_smbus_process_call(struct i2c_client * client, u8 command, u16 value); extern s32 i2c_smbus_block_process_call(struct i2c_client *client, -- cgit v1.2.3 From 4735c98f8447acb1c8977e2b8024640f7bf36dd6 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Mon, 14 Jul 2008 22:38:36 +0200 Subject: i2c: Add detection capability to new-style drivers Add a mechanism to let new-style i2c drivers optionally autodetect devices they would support on selected buses and ask i2c-core to instantiate them. This is a replacement for legacy i2c drivers, much cleaner. Where drivers had to implement both a legacy i2c_driver and a new-style i2c_driver so far, this mechanism makes it possible to get rid of the legacy i2c_driver and implement both enumerated and detected device support with just one (new-style) i2c_driver. Here is a quick conversion guide for these drivers, step by step: * Delete the legacy driver definition, registration and removal. Delete the attach_adapter and detach_client methods of the legacy driver. * Change the prototype of the legacy detect function from static int foo_detect(struct i2c_adapter *adapter, int address, int kind); to static int foo_detect(struct i2c_client *client, int kind, struct i2c_board_info *info); * Set the new-style driver detect callback to this new function, and set its address_data to &addr_data (addr_data is generally provided by I2C_CLIENT_INSMOD.) * Add the appropriate class to the new-style driver. This is typically the class the legacy attach_adapter method was checking for. Class checking is now mandatory (done by i2c-core.) See for the list of available classes. * Remove the i2c_client allocation and freeing from the detect function. A pre-allocated client is now handed to you by i2c-core, and is freed automatically. * Make the detect function fill the type field of the i2c_board_info structure it was passed as a parameter, and return 0, on success. If the detection fails, return -ENODEV. Signed-off-by: Jean Delvare --- Documentation/i2c/writing-clients | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'Documentation') diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients index 63722d3c9cdf..6b61b3a2e90b 100644 --- a/Documentation/i2c/writing-clients +++ b/Documentation/i2c/writing-clients @@ -44,6 +44,10 @@ static struct i2c_driver foo_driver = { .id_table = foo_ids, .probe = foo_probe, .remove = foo_remove, + /* if device autodetection is needed: */ + .class = I2C_CLASS_SOMETHING, + .detect = foo_detect, + .address_data = &addr_data, /* else, driver uses "legacy" binding model: */ .attach_adapter = foo_attach_adapter, @@ -217,6 +221,31 @@ in the I2C bus driver. You may want to save the returned i2c_client reference for later use. +Device Detection (Standard driver model) +---------------------------------------- + +Sometimes you do not know in advance which I2C devices are connected to +a given I2C bus. This is for example the case of hardware monitoring +devices on a PC's SMBus. In that case, you may want to let your driver +detect supported devices automatically. This is how the legacy model +was working, and is now available as an extension to the standard +driver model (so that we can finally get rid of the legacy model.) + +You simply have to define a detect callback which will attempt to +identify supported devices (returning 0 for supported ones and -ENODEV +for unsupported ones), a list of addresses to probe, and a device type +(or class) so that only I2C buses which may have that type of device +connected (and not otherwise enumerated) will be probed. The i2c +core will then call you back as needed and will instantiate a device +for you for every successful detection. + +Note that this mechanism is purely optional and not suitable for all +devices. You need some reliable way to identify the supported devices +(typically using device-specific, dedicated identification registers), +otherwise misdetections are likely to occur and things can get wrong +quickly. + + Device Deletion (Standard driver model) --------------------------------------- -- cgit v1.2.3 From a41eebab7537890409ea9dfe0fcda9b5fbdb090d Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 14 Jul 2008 16:41:12 -0400 Subject: ftrace: document updates The following updates were recommended by Elias Oltmanns and Randy Dunlap. [ updates based on Andrew Morton's comments are still to come. ] Signed-off-by: Steven Rostedt Signed-off-by: Linus Torvalds --- Documentation/ftrace.txt | 134 +++++++++++++++++++++++++---------------------- 1 file changed, 71 insertions(+), 63 deletions(-) (limited to 'Documentation') diff --git a/Documentation/ftrace.txt b/Documentation/ftrace.txt index 13e4bf054c38..77d3faa1a611 100644 --- a/Documentation/ftrace.txt +++ b/Documentation/ftrace.txt @@ -2,8 +2,11 @@ ======================== Copyright 2008 Red Hat Inc. -Author: Steven Rostedt + Author: Steven Rostedt + License: The GNU Free Documentation License, Version 1.2 +Reviewers: Elias Oltmanns and Randy Dunlap +Writen for: 2.6.26-rc8 linux-2.6-tip.git tip/tracing/ftrace branch Introduction ------------ @@ -46,7 +49,7 @@ of ftrace. Here is a list of some of the key files: that is configured. available_tracers : This holds the different types of tracers that - has been compiled into the kernel. The tracers + have been compiled into the kernel. The tracers listed here can be configured by echoing in their name into current_tracer. @@ -90,11 +93,13 @@ of ftrace. Here is a list of some of the key files: trace_entries : This sets or displays the number of trace entries each CPU buffer can hold. The tracer buffers are the same size for each CPU, so care must be - taken when modifying the trace_entries. The number - of actually entries will be the number given - times the number of possible CPUS. The buffers - are saved as individual pages, and the actual entries - will always be rounded up to entries per page. + taken when modifying the trace_entries. The trace + buffers are allocated in pages (blocks of memory that + the kernel uses for allocation, usually 4 KB in size). + Since each entry is smaller than a page, if the last + allocated page has room for more entries than were + requested, the rest of the page is used to allocate + entries. This can only be updated when the current_tracer is set to "none". @@ -114,13 +119,13 @@ of ftrace. Here is a list of some of the key files: in performance. This also has a side effect of enabling or disabling specific functions to be traced. Echoing in names of functions into this - file will limit the trace to only those files. + file will limit the trace to only these functions. set_ftrace_notrace: This has the opposite effect that set_ftrace_filter has. Any function that is added here will not be traced. If a function exists - in both set_ftrace_filter and set_ftrace_notrace - the function will _not_ bet traced. + in both set_ftrace_filter and set_ftrace_notrace, + the function will _not_ be traced. available_filter_functions : When a function is encountered the first time by the dynamic tracer, it is recorded and @@ -138,7 +143,7 @@ Here are the list of current tracers that can be configured. ftrace - function tracer that uses mcount to trace all functions. It is possible to filter out which functions that are - traced when dynamic ftrace is configured in. + to be traced when dynamic ftrace is configured in. sched_switch - traces the context switches between tasks. @@ -297,13 +302,13 @@ explains which is which. The above is mostly meaningful for kernel developers. - time: This differs from the trace output where as the trace output - contained a absolute timestamp. This timestamp is relative - to the start of the first entry in the the trace. + time: This differs from the trace file output. The trace file output + included an absolute timestamp. The timestamp used by the + latency_trace file is relative to the start of the trace. delay: This is just to help catch your eye a bit better. And needs to be fixed to be only relative to the same CPU. - The marks is determined by the difference between this + The marks are determined by the difference between this current trace and the next trace. '!' - greater than preempt_mark_thresh (default 100) '+' - greater than 1 microsecond @@ -322,13 +327,13 @@ output. To see what is available, simply cat the file: print-parent nosym-offset nosym-addr noverbose noraw nohex nobin \ noblock nostacktrace nosched-tree -To disable one of the options, echo in the option appended with "no". +To disable one of the options, echo in the option prepended with "no". echo noprint-parent > /debug/tracing/iter_ctrl To enable an option, leave off the "no". - echo sym-offest > /debug/tracing/iter_ctrl + echo sym-offset > /debug/tracing/iter_ctrl Here are the available options: @@ -344,7 +349,7 @@ Here are the available options: sym-offset - Display not only the function name, but also the offset in the function. For example, instead of seeing just - "ktime_get" you will see "ktime_get+0xb/0x20" + "ktime_get", you will see "ktime_get+0xb/0x20". sym-offset: bash-4000 [01] 1477.606694: simple_strtoul+0x6/0xa0 @@ -364,7 +369,7 @@ Here are the available options: user applications that can translate the raw numbers better than having it done in the kernel. - hex - similar to raw, but the numbers will be in a hexadecimal format. + hex - Similar to raw, but the numbers will be in a hexadecimal format. bin - This will print out the formats in raw binary. @@ -381,7 +386,7 @@ sched_switch ------------ This tracer simply records schedule switches. Here's an example -on how to implement it. +of how to use it. # echo sched_switch > /debug/tracing/current_tracer # echo 1 > /debug/tracing/tracing_enabled @@ -470,7 +475,7 @@ interrupt from triggering or the mouse interrupt from letting the kernel know of a new mouse event. The result is a latency with the reaction time. -The irqsoff tracer tracks the time interrupts are disabled and when +The irqsoff tracer tracks the time interrupts are disabled to the time they are re-enabled. When a new maximum latency is hit, it saves off the trace so that it may be retrieved at a later time. Every time a new maximum in reached, the old saved trace is discarded and the new @@ -519,7 +524,7 @@ The difference between the 6 and the displayed timestamp 7us is because the clock must have incremented between the time of recording the max latency and recording the function that had that latency. -Note the above had ftrace_enabled not set. If we set the ftrace_enabled +Note the above had ftrace_enabled not set. If we set the ftrace_enabled, we get a much larger output: # tracer: irqsoff @@ -570,21 +575,21 @@ vim:ft=help Here we traced a 50 microsecond latency. But we also see all the -functions that were called during that time. Note that enabling -function tracing we endure an added overhead. This overhead may -extend the latency times. But never the less, this trace has provided -some very helpful debugging. +functions that were called during that time. Note that by enabling +function tracing, we endure an added overhead. This overhead may +extend the latency times. But nevertheless, this trace has provided +some very helpful debugging information. preemptoff ---------- -When preemption is disabled we may be able to receive interrupts but -the task can not be preempted and a higher priority task must wait +When preemption is disabled, we may be able to receive interrupts but +the task cannot be preempted and a higher priority task must wait for preemption to be enabled again before it can preempt a lower priority task. -The preemptoff tracer traces the places that disables preemption. +The preemptoff tracer traces the places that disable preemption. Like the irqsoff, it records the maximum latency that preemption was disabled. The control of preemptoff is much like the irqsoff. @@ -696,7 +701,7 @@ Notice that the __do_softirq when called doesn't have a preempt_count. It may seem that we missed a preempt enabled. What really happened is that the preempt count is held on the threads stack and we switched to the softirq stack (4K stacks in effect). The code -does not copy the preempt count, but because interrupts are disabled +does not copy the preempt count, but because interrupts are disabled, we don't need to worry about it. Having a tracer like this is good to let people know what really happens inside the kernel. @@ -732,7 +737,7 @@ To record this time, use the preemptirqsoff tracer. Again, using this trace is much like the irqsoff and preemptoff tracers. - # echo preemptoff > /debug/tracing/current_tracer + # echo preemptirqsoff > /debug/tracing/current_tracer # echo 0 > /debug/tracing/tracing_max_latency # echo 1 > /debug/tracing/tracing_enabled # ls -ltr @@ -862,9 +867,9 @@ This is a very interesting trace. It started with the preemption of the ls task. We see that the task had the "need_resched" bit set with the 'N' in the trace. Interrupts are disabled in the spin_lock and the trace started. We see that a schedule took place to run -sshd. When the interrupts were enabled we took an interrupt. -On return of the interrupt the softirq ran. We took another interrupt -while running the softirq as we see with the capital 'H'. +sshd. When the interrupts were enabled, we took an interrupt. +On return from the interrupt handler, the softirq ran. We took another +interrupt while running the softirq as we see with the capital 'H'. wakeup @@ -876,9 +881,9 @@ time it executes. This is also known as "schedule latency". I stress the point that this is about RT tasks. It is also important to know the scheduling latency of non-RT tasks, but the average schedule latency is better for non-RT tasks. Tools like -LatencyTop is more appropriate for such measurements. +LatencyTop are more appropriate for such measurements. -Real-Time environments is interested in the worst case latency. +Real-Time environments are interested in the worst case latency. That is the longest latency it takes for something to happen, and not the average. We can have a very fast scheduler that may only have a large latency once in a while, but that would not work well @@ -889,8 +894,8 @@ tasks that are unpredictable will overwrite the worst case latency of RT tasks. Since this tracer only deals with RT tasks, we will run this slightly -different than we did with the previous tracers. Instead of performing -an 'ls' we will run 'sleep 1' under 'chrt' which changes the +differently than we did with the previous tracers. Instead of performing +an 'ls', we will run 'sleep 1' under 'chrt' which changes the priority of the task. # echo wakeup > /debug/tracing/current_tracer @@ -924,9 +929,9 @@ wakeup latency trace v1.1.5 on 2.6.26-rc8 vim:ft=help -Running this on an idle system we see that it only took 4 microseconds +Running this on an idle system, we see that it only took 4 microseconds to perform the task switch. Note, since the trace marker in the -schedule is before the actual "switch" we stop the tracing when +schedule is before the actual "switch", we stop the tracing when the recorded task is about to schedule in. This may change if we add a new marker at the end of the scheduler. @@ -992,12 +997,15 @@ ksoftirq-7 1d..4 50us : schedule (__cond_resched) The interrupt went off while running ksoftirqd. This task runs at SCHED_OTHER. Why didn't we see the 'N' set early? This may be -a harmless bug with x86_32 and 4K stacks. The need_reched() function -that tests if we need to reschedule looks on the actual stack. -Where as the setting of the NEED_RESCHED bit happens on the -task's stack. But because we are in a hard interrupt, the test -is with the interrupts stack which has that to be false. We don't -see the 'N' until we switch back to the task's stack. +a harmless bug with x86_32 and 4K stacks. On x86_32 with 4K stacks +configured, the interrupt and softirq runs with their own stack. +Some information is held on the top of the task's stack (need_resched +and preempt_count are both stored there). The setting of the NEED_RESCHED +bit is done directly to the task's stack, but the reading of the +NEED_RESCHED is done by looking at the current stack, which in this case +is the stack for the hard interrupt. This hides the fact that NEED_RESCHED +has been set. We don't see the 'N' until we switch back to the task's +assigned stack. ftrace ------ @@ -1067,10 +1075,10 @@ this works is the mcount function call (placed at the start of every kernel function, produced by the -pg switch in gcc), starts of pointing to a simple return. -When dynamic ftrace is initialized, it calls kstop_machine to make it -act like a uniprocessor so that it can freely modify code without -worrying about other processors executing that same code. At -initialization, the mcount calls are change to call a "record_ip" +When dynamic ftrace is initialized, it calls kstop_machine to make +the machine act like a uniprocessor so that it can freely modify code +without worrying about other processors executing that same code. At +initialization, the mcount calls are changed to call a "record_ip" function. After this, the first time a kernel function is called, it has the calling address saved in a hash table. @@ -1085,8 +1093,8 @@ traced, is that we can now selectively choose which functions we want to trace and which ones we want the mcount calls to remain as nops. -Two files that contain to the enabling and disabling of recorded -functions are: +Two files are used, one for enabling and one for disabling the tracing +of recorded functions. They are: set_ftrace_filter @@ -1094,7 +1102,7 @@ and set_ftrace_notrace -A list of available functions that you can add to this files is listed +A list of available functions that you can add to these files is listed in: available_filter_functions @@ -1133,9 +1141,9 @@ sys_nanosleep Perhaps this isn't enough. The filters also allow simple wild cards. -Only the following is currently available +Only the following are currently available - * - will match functions that begins with + * - will match functions that begin with * - will match functions that end with ** - will match functions that have in it @@ -1187,7 +1195,7 @@ This is because the '>' and '>>' act just like they do in bash. To rewrite the filters, use '>' To append to the filters, use '>>' -To clear out a filter so that all functions will be recorded again. +To clear out a filter so that all functions will be recorded again: # echo > /debug/tracing/set_ftrace_filter # cat /debug/tracing/set_ftrace_filter @@ -1246,8 +1254,8 @@ ftraced As mentioned above, when dynamic ftrace is configured in, a kernel thread wakes up once a second and checks to see if there are mcount -calls that need to be converted into nops. If there is not, then -it simply goes back to sleep. But if there is, it will call +calls that need to be converted into nops. If there are not any, then +it simply goes back to sleep. But if there are some, it will call kstop_machine to convert the calls to nops. There may be a case that you do not want this added latency. @@ -1262,8 +1270,8 @@ mcount calls to nops. Remember that there's a large overhead to calling mcount. Without this kernel thread, that overhead will exist. -Any write to the ftraced_enabled file will cause the kstop_machine -to run if there are recorded calls to mcount. This means that a +If there are recorded calls to mcount, any write to the ftraced_enabled +file will cause the kstop_machine to run. This means that a user can manually perform the updates when they want to by simply echoing a '0' into the ftraced_enabled file. @@ -1315,7 +1323,7 @@ trace entries Having too much or not enough data can be troublesome in diagnosing some issue in the kernel. The file trace_entries is used to modify -the size of the internal trace buffers. The numbers listed +the size of the internal trace buffers. The number listed is the number of entries that can be recorded per CPU. To know the full size, multiply the number of possible CPUS with the number of entries. @@ -1323,7 +1331,7 @@ number of entries. # cat /debug/tracing/trace_entries 65620 -Note, to modify this you must have tracing fulling disabled. To do that, +Note, to modify this, you must have tracing completely disabled. To do that, echo "none" into the current_tracer. # echo none > /debug/tracing/current_tracer @@ -1344,7 +1352,7 @@ it will add them. This shows us that 85 entries can fit on a single page. The number of pages that will be allocated is a percentage of available -memory. Allocating too much will produces an error. +memory. Allocating too much will produce an error. # echo 1000000000000 > /debug/tracing/trace_entries -bash: echo: write error: Cannot allocate memory -- cgit v1.2.3 From d3af01f18bf18e9b2a95711894fc239daeab5e2e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 15 Jul 2008 15:04:56 +0200 Subject: Documentation: document debugpat commandline option Signed-off-by: Thomas Gleixner --- Documentation/kernel-parameters.txt | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index b3a5aad7e629..681d6152e003 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -571,6 +571,8 @@ and is between 256 and 4096 characters. It is defined in the file debug_objects [KNL] Enable object debugging + debugpat [X86] Enable PAT debugging + decnet.addr= [HW,NET] Format: [,] See also Documentation/networking/decnet.txt. -- cgit v1.2.3 From 232595eaff951e96cabe5e85fed35f66b72ff51e Mon Sep 17 00:00:00 2001 From: Bartlomiej Zolnierkiewicz Date: Tue, 15 Jul 2008 21:21:46 +0200 Subject: ide: remove obsoleted "hdx=" kernel parameters * Remove obsoleted "hdx=" kernel parameters. * Remove no longer used stridx() and match_parm(). Signed-off-by: Bartlomiej Zolnierkiewicz --- Documentation/kernel-parameters.txt | 3 --- 1 file changed, 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index b52f47d588b4..faeea507cdca 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -722,9 +722,6 @@ and is between 256 and 4096 characters. It is defined in the file hd= [EIDE] (E)IDE hard drive subsystem geometry Format: ,, - hd?= [HW] (E)IDE subsystem - hd?lun= See Documentation/ide/ide.txt. - highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact size of . This works even on boxes that have no highmem otherwise. This also works to reduce highmem -- cgit v1.2.3