talos-obmc-linux/tools/perf/util/jitdump.c, branch dev-4.10

perf jit: Check JITHEADER_VERSION

2016-10-24T14:07:40+00:00

Check the version number when opening a jitdump file. Accept older versions, but not newer ones. Signed-off-by: Stefano Sanfilippo Signed-off-by: Ross McIlroy Reviewed-by: Stephane Eranian Cc: Anton Blanchard Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1476356383-30100-9-git-send-email-eranian@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf jit: Generate .eh_frame/.eh_frame_hdr in DSO

2016-10-24T14:07:40+00:00

When the jit_buf_desc contains unwinding information, it is emitted as eh_frame unwinding sections in the DSOs generated by perf inject. The unwinding information is required to unwind of JITed code which do not maintain the frame pointer register during function calls. It can be emitted by V8 / Chromium when the --perf_prof_unwinding_info is passed to V8. The eh_frame and eh_frame_hdr sections are emitted immediately after the .text. The .eh_frame is aligned at a 8-byte boundary, and .eh_frame_hdr at a 4-byte one. Since size of the .eh_frame is required to be a multiple of the word size, which means there will never be additional padding between it and the .eh_frame_hdr on machines where the word size is 4 or 8 bytes. However, additional padding might be inserted between .text and .eh_frame to reach the correct alignment, which will always be 8 bytes, also on 32bit machines. The reasoning behind this choice is that 4 extra bytes of padding worst case are not a large cost for the advantage of removing word-size dependent offset calculations when emitting the jitdump. Signed-off-by: Stefano Sanfilippo Signed-off-by: Ross McIlroy Reviewed-by: Stephane Eranian Cc: Anton Blanchard Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1476356383-30100-8-git-send-email-eranian@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf jit: Add unwinding support

2016-10-24T14:07:39+00:00

This record is intended to provide unwinding information in the eh_frame format. This is required to unwind JITed code which does not maintain the frame pointer register during function calls. The eh_frame unwinding information can be emitted by V8 / Chromium when the --perf_prof_unwinding_info is passed. A record of type jr_code_unwinding_info comes before the jr_code_load it referred to and contains both the .eh_frame and .eh_frame_hdr. The fields in the header have the following meaning: * unwinding_size: size of the eh_frame and eh_frame_hdr, necessary for distinguishing the content from the padding. * eh_frame_hdr_size: as the name says. * mapped_size: size of the payload that was in memory at runtime. typically unwinding_size if the .eh_frame_hdr and .eh_frame were mapped, or 0 if they weren't. It should always be the former case, since the .eh_frame is guaranteed to be mapped in memory. However, certain JITs might want to inject an .eh_frame_hdr with an empty LUT to trigger fp-based unwinding fallback in libunwind. The only part of the .eh_frame_hdr that libunwind reads from remote memory is the LUT, and since there is none, mapping the unwinding info in memory is not necessary, and 0 in this field signifies that it wasn't. This practical hack allows to save bytes in code memory for those JIT compilers that might or might not maintain a valid frame pointer. The payload that follows is assumed to contain first the .eh_frame and then the .eh_header_hdr, with no padding between the two. Signed-off-by: Stefano Sanfilippo Signed-off-by: Ross McIlroy Reviewed-by: Stephane Eranian Cc: Anton Blanchard Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1476356383-30100-7-git-send-email-eranian@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf jit: Make perf skip unknown records

2016-10-24T14:07:38+00:00

The behavior before this commit was to skip the remaining portion of the jitdump in case an unknown record was found, including those records that perf could handle. With this change, parsing a record with an unknown id will cause a warning to be emitted, the record will be skipped and parsing will resume from the next (valid) one. The patch aims at making perf more future proof, by extracting as much information as possible from jitdumps. Signed-off-by: Stefano Sanfilippo Signed-off-by: Ross McIlroy Reviewed-by: Stephane Eranian Cc: Anton Blanchard Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1476356383-30100-5-git-send-email-eranian@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf jit: Avoid returning garbage for a ret variable

2016-10-24T14:07:36+00:00

When the loop body isn't executed at all, then the 'ret' local variable, that is uninitialized will be used as the return value. This triggers this error on Alpine Linux: CC /tmp/build/perf/util/demangle-java.o CC /tmp/build/perf/util/demangle-rust.o CC /tmp/build/perf/util/jitdump.o CC /tmp/build/perf/util/genelf.o util/jitdump.c: In function 'jit_process': util/jitdump.c:622:3: error: 'ret' may be used uninitialized in this function [-Werror=maybe-uninitialized] fprintf(stderr, "injected: %s (%d)\n", path, ret); ^ util/jitdump.c:584:6: note: 'ret' was declared here int ret; ^ FLEX /tmp/build/perf/util/parse-events-flex.c / $ gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-alpine-linux-musl/5.3.0/lto-wrapper Target: x86_64-alpine-linux-musl Configured with: /home/buildozer/aports/main/gcc/src/gcc-5.3.0/configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info +--build=x86_64-alpine-linux-musl --host=x86_64-alpine-linux-musl --target=x86_64-alpine-linux-musl --with-pkgversion='Alpine 5.3.0' --enable-checking=release +--disable-fixed-point --disable-libstdcxx-pch --disable-multilib --disable-nls --disable-werror --disable-symvers --enable-__cxa_atexit --enable-esp +--enable-cloog-backend --enable-languages=c,c++,objc,java,fortran,ada --disable-libssp --disable-libmudflap --disable-libsanitizer --enable-shared +--enable-threads --enable-tls --with-system-zlib Thread model: posix gcc version 5.3.0 (Alpine 5.3.0) But this so far got under the radar, not causing any build problem, till the "perf jit: enable jitdump support without dwarf" gets applied, when the above problem takes place, some combination of inlining or whatever, the problem is real, so fix it by initializing the variable to zero. Cc: Anton Blanchard Cc: Jiri Olsa Cc: Maciej Debski Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian Link: https://lkml.kernel.org/r/20161013200437.GA12815@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf jitdump: Add the right header to get the major()/minor() definitions

2016-08-15T16:10:28+00:00

Noticed on Fedora Rawhide: $ gcc --version gcc (GCC) 6.1.1 20160721 (Red Hat 6.1.1-4) $ rpm -q glibc glibc-2.24.90-1.fc26.x86_64 $ CC /tmp/build/perf/util/jitdump.o util/jitdump.c: In function 'jit_repipe_code_load': util/jitdump.c:428:2: error: '__major_from_sys_types' is deprecated: In the GNU C Library, `major' is defined by . For historical compatibility, it is currently defined by as well, but we plan to remove this soon. To use `major', include directly. If you did not intend to use a system-defined macro `major', you should #undef it after including . [-Werror=deprecated-declarations] event->mmap2.maj = major(st.st_dev); ^~~~~ In file included from /usr/include/features.h:397:0, from /usr/include/sys/types.h:25, from util/jitdump.c:1: /usr/include/sys/sysmacros.h:87:1: note: declared here __SYSMACROS_DEFINE_MAJOR (__SYSMACROS_FST_IMPL_TEMPL) Fix it following that recomendation. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Stephane Eranian Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-3majvd0adhfr25rvx4v5e9te@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf evlist: Rename for_each() macros to for_each_entry()

2016-06-23T14:26:15+00:00

To match the semantics for list.h in the kernel, that are used to implement those macros. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Milian Wolff Cc: Namhyung Kim Cc: Taeung Song Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-qbcjlgj0ffxquxscahbpddi3@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf jit: memset() variable 'st' using the correct size

2016-04-19T15:37:01+00:00

The current code is memsetting the 'struct stat' variable 'st' with the size of 'stat' (which turns out to be 1 byte) rather than the size of variable 'sz'. Committer notes: sizeof(function) isn't valid, the result depends on the compiler used, with gcc, enabling pedantic warnings we get: $ cat sizeof_function.c #include #include #include #include int main(void) { printf("sizeof(stat)=%zd, stat=%p\n", sizeof(stat), stat); return 0; } $ readelf -sW sizeof_function | grep -w stat 49: 0000000000400630 16 FUNC WEAK HIDDEN 13 stat $ cc -pedantic sizeof_function.c -o sizeof_function sizeof_function.c: In function ‘main’: sizeof_function.c:8:46: warning: invalid application of ‘sizeof’ to a function type [-Wpointer-arith] printf("sizeof(stat)=%zd, stat=%p\n", sizeof(stat), stat); ^ $ ./sizeof_function sizeof(stat)=1, stat=0x400630 $ Standard C, section 6.5.3.4: "The sizeof operator shall not be applied to an expression that has function type or an incomplete type, to the parenthesized name of such a type, or to an expression that designates a bit-field member." http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf Signed-off-by: Colin Ian King Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Peter Zijlstra Cc: Stephane Eranian Fixes: 9b07e27f88b9 ("perf inject: Add jitdump mmap injection support") Link: http://lkml.kernel.org/r/1461020838-9260-1-git-send-email-colin.king@canonical.com Signed-off-by: Arnaldo Carvalho de Melo

perf jit: Add support for using TSC as a timestamp

2016-04-01T21:42:55+00:00

Intel PT uses TSC as a timestamp, so add support for using TSC instead of the monotonic clock. Use of TSC is selected by an environment variable "JITDUMP_USE_ARCH_TIMESTAMP" and flagged in the jitdump file with flag JITDUMP_FLAGS_ARCH_TIMESTAMP. Signed-off-by: Adrian Hunter Cc: Alexander Shishkin Cc: He Kuang Cc: Jiri Olsa Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Sukadev Bhattiprolu Cc: Wang Nan Link: http://lkml.kernel.org/r/1457426330-30226-1-git-send-email-adrian.hunter@intel.com [ Added the fixup from He Kuang to make it build on other arches, ] [ such as aarch64, to avoid inserting this bisectiong breakage upstream ] Link: http://lkml.kernel.org/r/1459482572-129494-1-git-send-email-hekuang@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add missing initialization of perf_sample.cpumode in synthesized samples

2016-03-29T23:03:56+00:00

In 473398a21d28 ("perf tools: Add cpumode to struct perf_sample"), I missed some places where perf_sample fields are directly initialized in addition to what is done in perf_evsel__parse_sample(), namely when synthesizing PERF_RECORD_{MMAP*,COMM,FORK,EXIT} for pre-existing threads and also in intel_pt and intel_bts when synthesizing events from processor trace, the jitdump code also was affected, fix it. The problem was noticed with running: # perf record -e intel_pt//u true # perf script Where the samples wouldn't get resolved because perf_sample.cpumode would be left as zero, i.e. PERF_RECORD_MISC_CPUMODE_UNKNOWN, not resolving as kernel, hypervisor or user cpu modes. Cc: Alexander Shishkin Cc: Andi Kleen Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Fixes: 473398a21d28 ("perf tools: Add cpumode to struct perf_sample") Link: http://lkml.kernel.org/n/tip-n5sdauxgk24d5nun8kuuu2mh@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo