From: Jed Davis <jld@mozilla.com>
Date: Thu, 20 Jun 2013 09:16:29 +0000 (+0100)
Subject: ARM: 7765/1: perf: Record the user-mode PC in the call chain.
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=c5f927a6f62196226915f12194c9d0df4e2210d7;p=deliverable%2Flinux.git

ARM: 7765/1: perf: Record the user-mode PC in the call chain.

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.

Cc: <stable@vger.kernel.org>
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>
---

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index 8c3094d0f7b7..d9f5cd4e533f 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -569,6 +569,7 @@ perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
 		return;
 	}
 
+	perf_callchain_store(entry, regs->ARM_pc);
 	tail = (struct frame_tail __user *)regs->ARM_fp - 1;
 
 	while ((entry->nr < PERF_MAX_STACK_DEPTH) &&