powerpc/perf: Move code to select SIAR or pt_regs into perf_read_regs
The logic to choose whether to use the SIAR or get the information
out of pt_regs is going to get more complicated, so do it once in
perf_read_regs.
We overload regs->result which is gross but we are already doing it
with regs->dsisr.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/perf_event.h b/arch/powerpc/include/asm/perf_event.h
index 5c16b89..0bb2372 100644
--- a/arch/powerpc/include/asm/perf_event.h
+++ b/arch/powerpc/include/asm/perf_event.h
@@ -26,8 +26,13 @@
#include <asm/ptrace.h>
#include <asm/reg.h>
+/*
+ * Overload regs->result to specify whether we should use the MSR (result
+ * is zero) or the SIAR (result is non zero).
+ */
#define perf_arch_fetch_caller_regs(regs, __ip) \
do { \
+ (regs)->result = 0; \
(regs)->nip = __ip; \
(regs)->gpr[1] = *(unsigned long *)__get_SP(); \
asm volatile("mfmsr %0" : "=r" ((regs)->msr)); \