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perf/x86: Store user space frame-pointer value on a sample

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Store user space frame-pointer value (BP register) into the perf trace
on a sample for a process so the value becomes available when
unwinding call stacks for functions gaining event samples.

Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/311d4a34-f81b-5535-3385-01427ac73b41@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Alexey Budankov 2018-05-24 17:11:54 +03:00 committed by Ingo Molnar
parent 82489c5fe5
commit 10b1105004
1 changed files with 6 additions and 4 deletions
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10
arch/x86/kernel/perf_regs.c
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@ -151,17 +151,19 @@ void perf_get_regs_user(struct perf_regs *regs_user,
regs_user_copy->sp = user_regs->sp;
regs_user_copy->cs = user_regs->cs;
regs_user_copy->ss = user_regs->ss;
/*
* Most system calls don't save these registers, don't report them.
* Store user space frame-pointer value on sample
* to facilitate stack unwinding for cases when
* user space executable code has such support
* enabled at compile time:
*/
regs_user_copy->bp = user_regs->bp;
regs_user_copy->bx = -1;
regs_user_copy->bp = -1;
regs_user_copy->r12 = -1;
regs_user_copy->r13 = -1;
regs_user_copy->r14 = -1;
regs_user_copy->r15 = -1;
/*
* For this to be at all useful, we need a reasonable guess for
* the ABI. Be careful: we're in NMI context, and we're