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* ftrace: Allow for function tracing to record init functions on boot upSteven Rostedt (VMware)2017-03-241-0/+1
| | | | | | | | | | | | | | | | | | | Adding a hook into free_reserve_area() that informs ftrace that boot up init text is being free, lets ftrace safely remove those init functions from its records, which keeps ftrace from trying to modify text that no longer exists. Note, this still does not allow for tracing .init text of modules, as modules require different work for freeing its init code. Link: http://lkml.kernel.org/r/1488502497.7212.24.camel@linux.intel.com Cc: linux-mm@kvack.org Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Peter Zijlstra <peterz@infradead.org> Requested-by: Todd Brandt <todd.e.brandt@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* recordmcount: arm: Implement make_nopStephen Boyd2016-11-141-0/+65
| | | | | | | | | | | | | In similar spirit to x86 and arm64 support, add a make_nop_arm() to replace calls to mcount with a nop in sections that aren't traced. Link: http://lkml.kernel.org/r/20161018234200.5804-1-sboyd@codeaurora.org Acked-by: Russell King <rmk+kernel@armlinux.org.uk> Acked-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* nmi_backtrace: generate one-line reports for idle cpusChris Metcalf2016-10-071-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | When doing an nmi backtrace of many cores, most of which are idle, the output is a little overwhelming and very uninformative. Suppress messages for cpus that are idling when they are interrupted and just emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN". We do this by grouping all the cpuidle code together into a new .cpuidle.text section, and then checking the address of the interrupted PC to see if it lies within that section. This commit suitably tags x86 and tile idle routines, and only adds in the minimal framework for other architectures. Link: http://lkml.kernel.org/r/1472487169-14923-5-git-send-email-cmetcalf@mellanox.com Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Daniel Thompson <daniel.thompson@linaro.org> [arm] Tested-by: Petr Mladek <pmladek@suse.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* scripts/recordmcount.c: account for .softirqentry.textDmitry Vyukov2016-09-281-0/+1
| | | | | | | | | | | | | | | be7635e7287e ("arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections") added .softirqentry.text section, but it was not added to recordmcount. So functions in the section are untracable. Add the section to scripts/recordmcount.c and scripts/recordmcount.pl. Fixes: be7635e7287e ("arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections") Link: http://lkml.kernel.org/r/1474902626-73468-1-git-send-email-dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Steve Rostedt <rostedt@goodmis.org> Cc: <stable@vger.kernel.org> [4.6+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ftrace/recordmcount: Work around for addition of metag magic but not relocationsLaura Abbott2016-08-021-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | glibc recently did a sync up (94e73c95d9b5 "elf.h: Sync with the gabi webpage") that added a #define for EM_METAG but did not add relocations This triggers build errors: scripts/recordmcount.c: In function 'do_file': scripts/recordmcount.c:466:28: error: 'R_METAG_ADDR32' undeclared (first use in this function) case EM_METAG: reltype = R_METAG_ADDR32; ^~~~~~~~~~~~~~ scripts/recordmcount.c:466:28: note: each undeclared identifier is reported only once for each function it appears in scripts/recordmcount.c:468:20: error: 'R_METAG_NONE' undeclared (first use in this function) rel_type_nop = R_METAG_NONE; ^~~~~~~~~~~~ Work around this change with some more #ifdefery for the relocations. Fedora Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1354034 Link: http://lkml.kernel.org/r/1468005530-14757-1-git-send-email-labbott@redhat.com Cc: stable@vger.kernel.org # v3.9+ Cc: James Hogan <james.hogan@imgtec.com> Fixes: 00512bdd4573 ("metag: ftrace support") Reported-by: Ross Burton <ross.burton@intel.com> Signed-off-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace/scripts: Fix incorrect use of sprintf in recordmcountColin Ian King2016-01-041-1/+1
| | | | | | | | | | | | | | | | | | Fix build warning: scripts/recordmcount.c:589:4: warning: format not a string literal and no format arguments [-Wformat-security] sprintf("%s: failed\n", file); Fixes: a50bd43935586 ("ftrace/scripts: Have recordmcount copy the object file") Link: http://lkml.kernel.org/r/1451516801-16951-1-git-send-email-colin.king@canonical.com Cc: Li Bin <huawei.libin@huawei.com> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Will Deacon <will.deacon@arm.com> Cc: stable@vger.kernel.org # 2.6.37+ Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace/scripts: Have recordmcount copy the object fileSteven Rostedt (Red Hat)2015-12-161-35/+110
| | | | | | | | | | | | | | | | | | Russell King found that he had weird side effects when compiling the kernel with hard linked ccache. The reason was that recordmcount modified the kernel in place via mmap, and when a file gets modified twice by recordmcount, it will complain about it. To fix this issue, Russell wrote a patch that checked if the file was hard linked more than once and would unlink it if it was. Linus Torvalds was not happy with the fact that recordmcount does this in place modification. Instead of doing the unlink only if the file has two or more hard links, it does the unlink all the time. In otherwords, it always does a copy if it changed something. That is, it does the write out if a change was made. Cc: stable@vger.kernel.org # 2.6.37+ Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* scripts: recordmcount: break hardlinksRussell King2015-12-161-0/+14
| | | | | | | | | | | | recordmcount edits the file in-place, which can cause problems when using ccache in hardlink mode. Arrange for recordmcount to break a hardlinked object. Link: http://lkml.kernel.org/r/E1a7MVT-0000et-62@rmk-PC.arm.linux.org.uk Cc: stable@vger.kernel.org # 2.6.37+ Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* recordmcount: arm64: Replace the ignored mcount call into nopLi Bin2015-11-031-1/+23
| | | | | | | | | | | | | | | | | | | | | | | | By now, the recordmcount only records the function that in following sections: .text/.ref.text/.sched.text/.spinlock.text/.irqentry.text/ .kprobes.text/.text.unlikely For the function that not in these sections, the call mcount will be in place and not be replaced when kernel boot up. And it will bring performance overhead, such as do_mem_abort (in .exception.text section). This patch make the call mcount to nop for this case in recordmcount. Link: http://lkml.kernel.org/r/1446019445-14421-1-git-send-email-huawei.libin@huawei.com Link: http://lkml.kernel.org/r/1446193864-24593-4-git-send-email-huawei.libin@huawei.com Cc: <lkp@intel.com> Cc: <catalin.marinas@arm.com> Cc: <takahiro.akashi@linaro.org> Cc: <stable@vger.kernel.org> # 3.18+ Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Li Bin <huawei.libin@huawei.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* recordmcount: x86: Assign a meaningful value to rel_type_nopLi Bin2015-11-021-0/+2
| | | | | | | | | | | | | | Although, the default value of rel_type_nop is zero, and the value of R_386_NONE/R_X86_64_NONE is zero too, but it should be assigned a meaningful value explicitly, otherwise it looks confused. Assign R_386_NONE to rel_type_nop for 386, assign R_X86_64_NONE to rel_type_nop for x86_64. Link: http://lkml.kernel.org/r/1446020606-16352-1-git-send-email-huawei.libin@huawei.com Signed-off-by: Li Bin <huawei.libin@huawei.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* s390/ftrace,kprobes: allow to patch first instructionHeiko Carstens2014-10-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the function tracer is enabled, allow to set kprobes on the first instruction of a function (which is the function trace caller): If no kprobe is set handling of enabling and disabling function tracing of a function simply patches the first instruction. Either it is a nop (right now it's an unconditional branch, which skips the mcount block), or it's a branch to the ftrace_caller() function. If a kprobe is being placed on a function tracer calling instruction we encode if we actually have a nop or branch in the remaining bytes after the breakpoint instruction (illegal opcode). This is possible, since the size of the instruction used for the nop and branch is six bytes, while the size of the breakpoint is only two bytes. Therefore the first two bytes contain the illegal opcode and the last four bytes contain either "0" for nop or "1" for branch. The kprobes code will then execute/simulate the correct instruction. Instruction patching for kprobes and function tracer is always done with stop_machine(). Therefore we don't have any races where an instruction is patched concurrently on a different cpu. Besides that also the program check handler which executes the function trace caller instruction won't be executed concurrently to any stop_machine() execution. This allows to keep full fault based kprobes handling which generates correct pt_regs contents automatically. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/ftrace: remove 31 bit ftrace supportHeiko Carstens2014-10-091-4/+0
| | | | | | | | | | 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* Merge branch 'misc' of ↵Linus Torvalds2014-06-121-2/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild Pull kbuild misc updates from Michal Marek: "This is the non-critical part of kbuild for v3.16-rc1: - make deb-pkg can do s390x and arm64 - new patterns in scripts/tags.sh - scripts/tags.sh skips userspace tools' sources (which sometimes have copies of kernel structures) and symlinks - improvements to the objdiff tool - two new coccinelle patches - other minor fixes" * 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: scripts: objdiff: support directories for the augument of record command scripts: objdiff: fix a comment scripts: objdiff: change the extension of disassembly from .o to .dis scripts: objdiff: improve path flexibility for record command scripts: objdiff: remove unnecessary code scripts: objdiff: direct error messages to stderr scripts: objdiff: get the path to .tmp_objdiff more simply deb-pkg: Add automatic support for s390x architecture coccicheck: Add unneeded return variable test kbuild: Fix a typo in documentation kbuild: trivial - use tabs for code indent where possible kbuild: trivial - remove trailing empty lines coccinelle: Check for missing NULL terminators in of_device_id tables scripts/tags.sh: ignore symlink'ed source files scripts/tags.sh: add regular expression replacement pattern for memcg builddeb: add arm64 in the supported architectures builddeb: use $OBJCOPY variable instead of objcopy scripts/tags.sh: ignore code of user space tools scripts/tags.sh: add pattern for DEFINE_HASHTABLE .gitignore: ignore Module.symvers in all directories
| * kbuild: trivial - remove trailing empty linesMasahiro Yamada2014-06-101-2/+0
| | | | | | | | Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
* | ftrace: Add arm64 support to recordmcountAKASHI Takahiro2014-05-291-0/+7
|/ | | | | | | | | | | | | | | | | | | | | | Recordmcount utility under scripts is run, after compiling each object, to find out all the locations of calling _mcount() and put them into specific seciton named __mcount_loc. Then linker collects all such information into a table in the kernel image (between __start_mcount_loc and __stop_mcount_loc) for later use by ftrace. This patch adds arm64 specific definitions to identify such locations. There are two types of implementation, C and Perl. On arm64, only C version is used to build the kernel now that CONFIG_HAVE_C_RECORDMCOUNT is on. But Perl version is also maintained. This patch also contains a workaround just in case where a header file, elf.h, on host machine doesn't have definitions of EM_AARCH64 nor R_AARCH64_ABS64. Without them, compiling C version of recordmcount will fail. Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
* metag: ftrace supportJames Hogan2013-03-021-0/+13
| | | | | | | | | Add ftrace support for metag. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace/s390: mcount offset calculationMartin Schwidefsky2011-05-161-2/+6
| | | | | | | | Do the mcount offset adjustment in the recordmcount.pl/recordmcount.[ch] at compile time and not in ftrace_call_adjust at run time. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace/x86: mcount offset calculationMartin Schwidefsky2011-05-161-0/+2
| | | | | | | | Do the mcount offset adjustment in the recordmcount.pl/recordmcount.[ch] at compile time and not in ftrace_call_adjust at run time. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace/recordmcount: Add warning logic to warn on mcount not recordedSteven Rostedt2011-05-161-8/+24
| | | | | | | | | | | | | | | | There's some sections that should not have mcount recorded and should not have modifications to the that code. But currently they waste some time by calling mcount anyway (which simply returns). As the real answer should be to either whitelist the section or have gcc ignore it fully. This change adds a option to recordmcount to warn when it finds a section that is ignored by ftrace but still contains mcount callers. This is not on by default as developers may not know if the section should be completely ignored or added to the whitelist. Cc: John Reiser <jreiser@bitwagon.com> Link: http://lkml.kernel.org/r/20110421023738.476989377@goodmis.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace/recordmcount: Make ignored mcount calls into nops at compile timeSteven Rostedt2011-05-161-2/+38
| | | | | | | | | | | | | | | | | | | | | | | There are sections that are ignored by ftrace for the function tracing because the text is in a section that can be removed without notice. The mcount calls in these sections are ignored and ftrace never sees them. The downside of this is that the functions in these sections still call mcount. Although the mcount function is defined in assembly simply as a return, this added overhead is unnecessary. The solution is to convert these callers into nops at compile time. A better solution is to add 'notrace' to the section markers, but as new sections come up all the time, it would be nice that they are delt with when they are created. Later patches will deal with finding these sections and doing the proper solution. Thanks to H. Peter Anvin for giving me the right nops to use for x86. Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: John Reiser <jreiser@bitwagon.com> Link: http://lkml.kernel.org/r/20110421023738.237101176@goodmis.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace: Add .kprobe.text section to whitelist for recordmcount.cSteven Rostedt2011-05-161-0/+1
| | | | | | | | | | The .kprobe.text section is safe to modify mcount to nop and tracing. Add it to the whitelist in recordmcount.c and recordmcount.pl. Cc: John Reiser <jreiser@bitwagon.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Link: http://lkml.kernel.org/r/20110421023737.743350547@goodmis.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace/trivial: Clean up record mcount to use Linux switch styleSteven Rostedt2011-05-161-21/+22
| | | | | | | | | | | | | | | | | | | | The Linux style for switch statements is: switch (var) { case x: [...] break; } Not: switch (var) { case x: { [...] } break; Cc: John Reiser <jreiser@bitwagon.com> Link: http://lkml.kernel.org/r/20110421023737.523968644@goodmis.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace/trivial: Clean up recordmcount.c to use Linux style comparisonsSteven Rostedt2011-05-161-24/+24
| | | | | | | | | | | | | | | | | | | | | | The Linux ftrace subsystem style for comparing is: var == 1 var > 0 and not: 1 == var 0 < var It is considered that Linux developers are smart enough not to do the if (var = 1) mistake. Cc: John Reiser <jreiser@bitwagon.com> Link: http://lkml.kernel.org/r/20110421023737.290712238@goodmis.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace: Add .ref.text as one of the safe areas to traceSteven Rostedt2011-03-101-1/+2
| | | | | | | | The section .ref.text will not go away unexpectedly and is safe to trace. Add it to the safe list of sections to allow tracing. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ARM: 6511/1: ftrace: add ARM support for C version of recordmcountRabin Vincent2010-12-041-1/+4
| | | | | | | | | Depending on the compiler version, ARM GCC calls the mcount function either __gnu_mcount_nc or mcount. Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: 6509/1: ftrace: ignore any ftrace.o in C version of recordmcountRabin Vincent2010-12-041-1/+1
| | | | | | | | | arch/arm/kernel/ftrace.c references mcount like kernel/tracing/ftrace.c, so change the exclusion filter to match any ftrace.o. Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ftrace/MIPS: Add module support for C version of recordmcountWu Zhangjin2010-10-291-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since MIPS modules' address space differs from the core kernel space, to access the _mcount in the core kernel, the kernel functions in modules must use long call (-mlong-calls): load the _mcount address into one register and jump to the address stored by the register: c: 3c030000 lui v1,0x0 <--------> b label c: R_MIPS_HI16 _mcount c: R_MIPS_NONE *ABS* c: R_MIPS_NONE *ABS* 10: 64630000 daddiu v1,v1,0 10: R_MIPS_LO16 _mcount 10: R_MIPS_NONE *ABS* 10: R_MIPS_NONE *ABS* 14: 03e0082d move at,ra 18: 0060f809 jalr v1 label: In the old Perl version of recordmcount, we only need to record the position of the 1st R_MIPS_HI16 type of _mcount, and later, in ftrace_make_nop(), replace the instruction in this position by a "b label" and in ftrace_make_call(), replace it back. But, the default C version of recordmcount records all of the _mcount symbols, so, we must filter the 2nd _mcount like the Perl version of recordmcount does. The C version of recordmcount copes with the symbols before they are linked, So It doesn't know the type of the symbols and therefore can not filter the symbols as the Perl version of recordmcount does. But as we can see above, the 2nd _mcount symbols of the long call alawys follows the 1st _mcount symbol of the same long call, which means the offset from the 1st to the 2nd is fixed, it is 0x10-0xc = 4 here, 4 is the length of the 1st load instruciton, for MIPS has fixed length of instructions, this offset is always 4. And as we know, the _mcount is inserted into the entry of every kernel function, the offset between the other _mcount's is expected to be always bigger than 4. So, to filter the 2ns _mcount symbol of the long call, we can simply check the offset between two _mcount symbols, If it is 4, then, filter the 2nd _mcount symbol. To avoid touching too much code, an 'empty' function fn_is_fake_mcount() is added for all of the archs, and the specific archs can override it via chaning the function pointer: is_fake_mcount in do_file() with the e_machine. e.g. This patch adds MIPS_is_fake_mcount() to override the default fn_is_fake_mcount() pointed by is_fake_mcount. This fn_is_fake_mcount() checks if the _mcount symbol is fake, e.g. the 2nd _mcount symbol of the long call is fake, for there are 2 _mcount symbols mapped to one real mcount call, so, one of them is fake and must be filtered. This fn_is_fake_mcount() is called in sift_rel_mcount() after finding the _mcount symbols and before adding the _mcount symbol into mrelp, so, it can prevent the fake mcount symbol going into the last __mcount_loc table. Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> LKML-Reference: <b866f0138224340a132d31861fa3f9300dee30ac.1288176026.git.wuzhangjin@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* ftrace/MIPS: Add MIPS64 support for C version of recordmcountJohn Reiser2010-10-291-0/+41
| | | | | | | | | | | | | | | | | | | | | MIPS64 has 'weird' Elf64_Rel.r_info[1,2], which must be used instead of the generic Elf64_Rel.r_info, otherwise, the C version of recordmcount will not work for "segmentation fault". Usage of "union mips_r_info" and the functions MIPS64_r_sym() and MIPS64_r_info() written by Maciej W. Rozycki <macro@linux-mips.org> ---- [1] http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf [2] arch/mips/include/asm/module.h Tested-by: Wu Zhangjin <wuzhangjin@gmail.com> Signed-off-by: John Reiser <jreiser@BitWagon.com> Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> LKML-Reference: <AANLkTinwXjLAYACUfhLYaocHD_vBbiErLN3NjwN8JqSy@mail.gmail.com> LKML-Reference: <910dc2d5ae1ed042df4f96815fe4a433078d1c2a.1288176026.git.wuzhangjin@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* ftrace: Do not process kernel/trace/ftrace.o with C recordmcount programSteven Rostedt2010-10-151-2/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The file kernel/trace/ftrace.c references the mcount() call to convert the mcount() callers to nops. But because it references mcount(), the mcount() address is placed in the relocation table. The C version of recordmcount reads the relocation table of all object files, and it will add all references to mcount to the __mcount_loc table that is used to find the places that call mcount() and change the call to a nop. When recordmcount finds the mcount reference in kernel/trace/ftrace.o, it saves that location even though the code is not a call, but references mcount as data. On boot up, when all calls are converted to nops, the code has a safety check to determine what op code it is actually replacing before it replaces it. If that op code at the address does not match, then a warning is printed and the function tracer is disabled. The reference to mcount in ftrace.c, causes this warning to trigger, since the reference is not a call to mcount(). The ftrace.c file is not compiled with the -pg flag, so no calls to mcount() should be expected. This patch simply makes recordmcount.c skip the kernel/trace/ftrace.c file. This was the same solution used by the perl version of recordmcount. Reported-by: Ingo Molnar <mingo@elte.hu> Cc: John Reiser <jreiser@bitwagon.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace: Remove duplicate code for 64 and 32 bit in recordmcount.cSteven Rostedt2010-10-141-544/+4
| | | | | | | | | | | | | | | The elf reader for recordmcount.c had duplicate functions for both 32 bit and 64 bit elf handling. This was due to the need of using the 32 and 64 bit elf structures. This patch consolidates the two by using macros to define the 32 and 64 bit names in a recordmcount.h file, and then by just defining a RECORD_MCOUNT_64 macro and including recordmcount.h twice we create the funtions for both the 32 bit version as well as the 64 bit version using one code source. Cc: John Reiser <jreiser@bitwagon.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace: Add C version of recordmcount compile time codeJohn Reiser2010-10-141-0/+885
Currently, the mcount callers are found with a perl script that does an objdump on every file in the kernel. This is a C version of that same code which should increase the performance time of compiling the kernel with dynamic ftrace enabled. Signed-off-by: John Reiser <jreiser@bitwagon.com> [ Updated the code to include .text.unlikely section as well as changing the format to follow Linux coding style. ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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