user/sven/linux.git/scripts/recordmcount.c, branch v4.0

s390/ftrace,kprobes: allow to patch first instruction

2014-10-27T12:27:27Z

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 Signed-off-by: Martin Schwidefsky

s390/ftrace: remove 31 bit ftrace support

2014-10-09T07:14:18Z

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 Signed-off-by: Martin Schwidefsky

Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild

2014-06-13T04:29:20Z

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 lines

2014-06-09T22:04:06Z

Signed-off-by: Masahiro Yamada

ftrace: Add arm64 support to recordmcount

2014-05-29T08:04:31Z

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 Signed-off-by: AKASHI Takahiro Signed-off-by: Will Deacon

metag: ftrace support

2013-03-02T20:09:55Z

Add ftrace support for metag. Signed-off-by: James Hogan Cc: Frederic Weisbecker Cc: Ingo Molnar Reviewed-by: Steven Rostedt

ftrace/s390: mcount offset calculation

2011-05-16T19:05:06Z

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 Signed-off-by: Steven Rostedt

ftrace/x86: mcount offset calculation

2011-05-16T18:55:57Z

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 Signed-off-by: Steven Rostedt

ftrace/recordmcount: Add warning logic to warn on mcount not recorded

2011-05-16T18:44:20Z

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 Link: http://lkml.kernel.org/r/20110421023738.476989377@goodmis.org Signed-off-by: Steven Rostedt

ftrace/recordmcount: Make ignored mcount calls into nops at compile time

2011-05-16T18:43:32Z

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" Cc: John Reiser Link: http://lkml.kernel.org/r/20110421023738.237101176@goodmis.org Signed-off-by: Steven Rostedt