| From | Ben Hutchings <> | Date | Wed, 24 Jul 2013 15:02:45 +0100 | Subject | [34/85] ARM: 7765/1: perf: Record the user-mode PC in the call chain. |
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3.2.49-rc1 review patch. If anyone has any objections, please let me know.
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From: Jed Davis <jld@mozilla.com>
commit c5f927a6f62196226915f12194c9d0df4e2210d7 upstream.
With this change, we no longer lose the innermost entry in the user-mode part of the call chain. See also the x86 port, which includes the ip.
It's possible to partially work around this problem by post-processing the data to use the PERF_SAMPLE_IP value, but this works only if the CPU wasn't in the kernel when the sample was taken.
Signed-off-by: Jed Davis <jld@mozilla.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- arch/arm/kernel/perf_event.c | 1 + 1 file changed, 1 insertion(+)
--- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -795,6 +795,7 @@ perf_callchain_user(struct perf_callchai struct frame_tail __user *tail; + perf_callchain_store(entry, regs->ARM_pc); tail = (struct frame_tail __user *)regs->ARM_fp - 1; while ((entry->nr < PERF_MAX_STACK_DEPTH) &&
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