From d64ec10ec8b43a519f132e7c33c1815a4e86949e Mon Sep 17 00:00:00 2001 From: He Kuang Date: Fri, 3 Jun 2016 03:33:19 +0000 Subject: perf unwind: Check the target platform before assigning unwind methods Currently, 'perf script' uses host unwind methods to parse perf.data callchain info without taking the target architecture into account, i.e. assuming the perf.data file was generated on the same machine where the analysis is being performed. So we get wrong result without any warnings when unwinding callchains of x86(32-bit) on x86(64-bit) machine. This patch adds an extra step that checks the target platform before assigning unwind methods. In later patches in this series, we can use this info to assign the right unwind methods for supported platforms. Committer note: After fixing it to register the local unwinder for live mode tools ('perf trace', 'perf top'), i.e. tools that don't use a perf.data file, it works as intended and passes the 'perf test unwind' test: # perf trace -e nanosleep --call dwarf usleep 1 0.328 ( 0.058 ms): usleep/11115 nanosleep(rqtp: 0x7fff083fa480) = 0 __nanosleep_nocancel+0x7 (/usr/lib64/libc-2.22.so) usleep+0x34 (/usr/lib64/libc-2.22.so) main+0x1eb (/usr/bin/usleep) __libc_start_main+0xf0 (/usr/lib64/libc-2.22.so) _start+0x29 (/usr/bin/usleep) # perf test 48 48: Test dwarf unwind : Ok # Signed-off-by: He Kuang Acked-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: David Ahern Cc: Ekaterina Tumanova Cc: Josh Poimboeuf Cc: Kan Liang Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Pekka Enberg Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Sukadev Bhattiprolu Cc: Wang Nan Link: http://lkml.kernel.org/r/1464924803-22214-11-git-send-email-hekuang@huawei.com [ Fixed exit path for 'live' mode tools, where we need to default to local unwinding ] Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/unwind.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'tools/perf/util/unwind.h') diff --git a/tools/perf/util/unwind.h b/tools/perf/util/unwind.h index bbd73d9bea45..bf9f5937caee 100644 --- a/tools/perf/util/unwind.h +++ b/tools/perf/util/unwind.h @@ -30,11 +30,12 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg, /* libunwind specific */ #ifdef HAVE_LIBUNWIND_SUPPORT int libunwind__arch_reg_id(int regnum); -int unwind__prepare_access(struct thread *thread); +int unwind__prepare_access(struct thread *thread, struct map *map); void unwind__flush_access(struct thread *thread); void unwind__finish_access(struct thread *thread); #else -static inline int unwind__prepare_access(struct thread *thread __maybe_unused) +static inline int unwind__prepare_access(struct thread *thread __maybe_unused, + struct map *map __maybe_unused) { return 0; } @@ -53,7 +54,8 @@ unwind__get_entries(unwind_entry_cb_t cb __maybe_unused, return 0; } -static inline int unwind__prepare_access(struct thread *thread __maybe_unused) +static inline int unwind__prepare_access(struct thread *thread __maybe_unused, + struct map *map __maybe_unused) { return 0; } -- cgit v1.2.3-59-g8ed1b