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From: tip-bot for Frederic Weisbecker on 17 Mar 2010 05:50
Commit-ID: a6b84574eed7e4fd8cb8dac2d0926fe2cf34b941
Gitweb: http://git.kernel.org/tip/a6b84574eed7e4fd8cb8dac2d0926fe2cf34b941
Author: Frederic Weisbecker <fweisbec(a)gmail.com>
AuthorDate: Tue, 16 Mar 2010 01:05:02 +0100
Committer: Ingo Molnar <mingo(a)elte.hu>
CommitDate: Wed, 17 Mar 2010 10:44:42 +0100

perf: Fix unexported generic perf_arch_fetch_caller_regs

perf_arch_fetch_caller_regs() is exported for the overriden x86
version, but not for the generic weak version.

As a general rule, weak functions should not have their symbol
exported in the same file they are defined.

So let's export it on trace_event_perf.c as it is used by trace
events only.

This fixes:

ERROR: ".perf_arch_fetch_caller_regs" [fs/xfs/xfs.ko] undefined!
ERROR: ".perf_arch_fetch_caller_regs" [arch/powerpc/platforms/cell/spufs/spufs.ko] undefined!

-v2: And also only build it if trace events are enabled.
-v3: Fix changelog mistake

Reported-by: Stephen Rothwell <sfr(a)canb.auug.org.au>
Signed-off-by: Frederic Weisbecker <fweisbec(a)gmail.com>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Xiao Guangrong <xiaoguangrong(a)cn.fujitsu.com>
Cc: Paul Mackerras <paulus(a)samba.org>
LKML-Reference: <1268697902-9518-1-git-send-regression-fweisbec(a)gmail.com>
Signed-off-by: Ingo Molnar <mingo(a)elte.hu>
---
arch/x86/kernel/cpu/perf_event.c | 3 ++-
kernel/perf_event.c | 2 ++
kernel/trace/trace_event_perf.c | 2 ++
3 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 7645fae..60398a0 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1702,6 +1702,7 @@ struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
return entry;
}

+#ifdef CONFIG_EVENT_TRACING
void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip)
{
regs->ip = ip;
@@ -1713,4 +1714,4 @@ void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int ski
regs->cs = __KERNEL_CS;
local_save_flags(regs->flags);
}
-EXPORT_SYMBOL_GPL(perf_arch_fetch_caller_regs);
+#endif
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index fb3031c..574ee58 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -2786,10 +2786,12 @@ __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
return NULL;
}

+#ifdef CONFIG_EVENT_TRACING
__weak
void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip)
{
}
+#endif

/*
* Output
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 0709e4f..7d79a10 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -12,6 +12,8 @@
DEFINE_PER_CPU(struct pt_regs, perf_trace_regs);
EXPORT_PER_CPU_SYMBOL_GPL(perf_trace_regs);

+EXPORT_SYMBOL_GPL(perf_arch_fetch_caller_regs);
+
static char *perf_trace_buf;
static char *perf_trace_buf_nmi;

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Prev: [PATCH 2/4] stop_machine: reimplement using cpuhog
Next: [tip:perf/core] perf, x86: Report error code that returned from x86_pmu.hw_config()