trace doc: convert trace/uprobetracer.txt to rst format

This converts the plain text documentation to reStructuredText format and
add it into Sphinx TOC tree. No essential content change.

Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

1 files changed, 0 insertions, 165 deletions

diff --git a/Documentation/trace/uprobetracer.txt b/Documentation/trace/uprobetracer.txt
deleted file mode 100644
index bf526a7c5559..000000000000
--- a/Documentation/trace/uprobetracer.txt
+++ /dev/null
@@ -1,165 +0,0 @@
-            Uprobe-tracer: Uprobe-based Event Tracing
-            =========================================
-
-           Documentation written by Srikar Dronamraju
-
-
-Overview
---------
-Uprobe based trace events are similar to kprobe based trace events.
-To enable this feature, build your kernel with CONFIG_UPROBE_EVENTS=y.
-
-Similar to the kprobe-event tracer, this doesn't need to be activated via
-current_tracer. Instead of that, add probe points via
-/sys/kernel/debug/tracing/uprobe_events, and enable it via
-/sys/kernel/debug/tracing/events/uprobes/<EVENT>/enabled.
-
-However unlike kprobe-event tracer, the uprobe event interface expects the
-user to calculate the offset of the probepoint in the object.
-
-Synopsis of uprobe_tracer
--------------------------
-  p[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a uprobe
-  r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a return uprobe (uretprobe)
-  -:[GRP/]EVENT                           : Clear uprobe or uretprobe event
-
-  GRP           : Group name. If omitted, "uprobes" is the default value.
-  EVENT         : Event name. If omitted, the event name is generated based
-                  on PATH+OFFSET.
-  PATH          : Path to an executable or a library.
-  OFFSET        : Offset where the probe is inserted.
-
-  FETCHARGS     : Arguments. Each probe can have up to 128 args.
-   %REG         : Fetch register REG
-   @ADDR	: Fetch memory at ADDR (ADDR should be in userspace)
-   @+OFFSET	: Fetch memory at OFFSET (OFFSET from same file as PATH)
-   $stackN	: Fetch Nth entry of stack (N >= 0)
-   $stack	: Fetch stack address.
-   $retval	: Fetch return value.(*)
-   $comm	: Fetch current task comm.
-   +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
-   NAME=FETCHARG     : Set NAME as the argument name of FETCHARG.
-   FETCHARG:TYPE     : Set TYPE as the type of FETCHARG. Currently, basic types
-		       (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types
-		       (x8/x16/x32/x64), "string" and bitfield are supported.
-
-  (*) only for return probe.
-  (**) this is useful for fetching a field of data structures.
-
-Types
------
-Several types are supported for fetch-args. Uprobe tracer will access memory
-by given type. Prefix 's' and 'u' means those types are signed and unsigned
-respectively. 'x' prefix implies it is unsigned. Traced arguments are shown
-in decimal ('s' and 'u') or hexadecimal ('x'). Without type casting, 'x32'
-or 'x64' is used depends on the architecture (e.g. x86-32 uses x32, and
-x86-64 uses x64).
-String type is a special type, which fetches a "null-terminated" string from
-user space.
-Bitfield is another special type, which takes 3 parameters, bit-width, bit-
-offset, and container-size (usually 32). The syntax is;
-
- b<bit-width>@<bit-offset>/<container-size>
-
-For $comm, the default type is "string"; any other type is invalid.
-
-
-Event Profiling
----------------
-You can check the total number of probe hits and probe miss-hits via
-/sys/kernel/debug/tracing/uprobe_profile.
-The first column is event name, the second is the number of probe hits,
-the third is the number of probe miss-hits.
-
-Usage examples
---------------
- * Add a probe as a new uprobe event, write a new definition to uprobe_events
-as below: (sets a uprobe at an offset of 0x4245c0 in the executable /bin/bash)
-
-    echo 'p /bin/bash:0x4245c0' > /sys/kernel/debug/tracing/uprobe_events
-
- * Add a probe as a new uretprobe event:
-
-    echo 'r /bin/bash:0x4245c0' > /sys/kernel/debug/tracing/uprobe_events
-
- * Unset registered event:
-
-    echo '-:p_bash_0x4245c0' >> /sys/kernel/debug/tracing/uprobe_events
-
- * Print out the events that are registered:
-
-    cat /sys/kernel/debug/tracing/uprobe_events
-
- * Clear all events:
-
-    echo > /sys/kernel/debug/tracing/uprobe_events
-
-Following example shows how to dump the instruction pointer and %ax register
-at the probed text address. Probe zfree function in /bin/zsh:
-
-    # cd /sys/kernel/debug/tracing/
-    # cat /proc/`pgrep zsh`/maps | grep /bin/zsh | grep r-xp
-    00400000-0048a000 r-xp 00000000 08:03 130904 /bin/zsh
-    # objdump -T /bin/zsh | grep -w zfree
-    0000000000446420 g    DF .text  0000000000000012  Base        zfree
-
-  0x46420 is the offset of zfree in object /bin/zsh that is loaded at
-  0x00400000. Hence the command to uprobe would be:
-
-    # echo 'p:zfree_entry /bin/zsh:0x46420 %ip %ax' > uprobe_events
-
-  And the same for the uretprobe would be:
-
-    # echo 'r:zfree_exit /bin/zsh:0x46420 %ip %ax' >> uprobe_events
-
-Please note: User has to explicitly calculate the offset of the probe-point
-in the object. We can see the events that are registered by looking at the
-uprobe_events file.
-
-    # cat uprobe_events
-    p:uprobes/zfree_entry /bin/zsh:0x00046420 arg1=%ip arg2=%ax
-    r:uprobes/zfree_exit /bin/zsh:0x00046420 arg1=%ip arg2=%ax
-
-Format of events can be seen by viewing the file events/uprobes/zfree_entry/format
-
-    # cat events/uprobes/zfree_entry/format
-    name: zfree_entry
-    ID: 922
-    format:
-         field:unsigned short common_type;         offset:0;  size:2; signed:0;
-         field:unsigned char common_flags;         offset:2;  size:1; signed:0;
-         field:unsigned char common_preempt_count; offset:3;  size:1; signed:0;
-         field:int common_pid;                     offset:4;  size:4; signed:1;
-         field:int common_padding;                 offset:8;  size:4; signed:1;
-
-         field:unsigned long __probe_ip;           offset:12; size:4; signed:0;
-         field:u32 arg1;                           offset:16; size:4; signed:0;
-         field:u32 arg2;                           offset:20; size:4; signed:0;
-
-    print fmt: "(%lx) arg1=%lx arg2=%lx", REC->__probe_ip, REC->arg1, REC->arg2
-
-Right after definition, each event is disabled by default. For tracing these
-events, you need to enable it by:
-
-    # echo 1 > events/uprobes/enable
-
-Lets disable the event after sleeping for some time.
-
-    # sleep 20
-    # echo 0 > events/uprobes/enable
-
-And you can see the traced information via /sys/kernel/debug/tracing/trace.
-
-    # cat trace
-    # tracer: nop
-    #
-    #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
-    #              | |       |          |         |
-                 zsh-24842 [006] 258544.995456: zfree_entry: (0x446420) arg1=446420 arg2=79
-                 zsh-24842 [007] 258545.000270: zfree_exit:  (0x446540 <- 0x446420) arg1=446540 arg2=0
-                 zsh-24842 [002] 258545.043929: zfree_entry: (0x446420) arg1=446420 arg2=79
-                 zsh-24842 [004] 258547.046129: zfree_exit:  (0x446540 <- 0x446420) arg1=446540 arg2=0
-
-Output shows us uprobe was triggered for a pid 24842 with ip being 0x446420
-and contents of ax register being 79. And uretprobe was triggered with ip at
-0x446540 with counterpart function entry at 0x446420.