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 <an...@samba.org>
---
Other architectures appear to be playing similar overloading tricks
so we should probably solve this in a nicer way.
Index: linux-build/arch/powerpc/include/asm/perf_event.h
===================================================================
--- linux-build.orig/arch/powerpc/include/asm/perf_event.h 2012-06-26
10:26:40.000000000 +1000
+++ linux-build/arch/powerpc/include/asm/perf_event.h 2012-06-26
10:31:02.132149613 +1000
@@ -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)); \
Index: linux-build/arch/powerpc/perf/core-book3s.c
===================================================================
--- linux-build.orig/arch/powerpc/perf/core-book3s.c 2012-06-26
10:28:53.000000000 +1000
+++ linux-build/arch/powerpc/perf/core-book3s.c 2012-06-26 10:35:40.560886839
+1000
@@ -73,7 +73,10 @@ static inline u32 perf_get_misc_flags(st
{
return 0;
}
-static inline void perf_read_regs(struct pt_regs *regs) { }
+static inline void perf_read_regs(struct pt_regs *regs)
+{
+ regs->result = 0;
+}
static inline int perf_intr_is_nmi(struct pt_regs *regs)
{
return 0;
@@ -148,17 +151,9 @@ static inline u32 perf_flags_from_msr(st
static inline u32 perf_get_misc_flags(struct pt_regs *regs)
{
unsigned long mmcra = regs->dsisr;
+ unsigned long use_siar = regs->result;
- /* Not a PMU interrupt: Make up flags from regs->msr */
- if (TRAP(regs) != 0xf00)
- return perf_flags_from_msr(regs);
-
- /*
- * If we don't support continuous sampling and this
- * is not a marked event, same deal
- */
- if ((ppmu->flags & PPMU_NO_CONT_SAMPLING) &&
- !(mmcra & MMCRA_SAMPLE_ENABLE))
+ if (!use_siar)
return perf_flags_from_msr(regs);
/*
@@ -185,10 +180,24 @@ static inline u32 perf_get_misc_flags(st
/*
* Overload regs->dsisr to store MMCRA so we only need to read it once
* on each interrupt.
+ * Overload regs->result to specify whether we should use the MSR (result
+ * is zero) or the SIAR (result is non zero).
*/
static inline void perf_read_regs(struct pt_regs *regs)
{
- regs->dsisr = mfspr(SPRN_MMCRA);
+ unsigned long mmcra = mfspr(SPRN_MMCRA);
+ int marked = mmcra & MMCRA_SAMPLE_ENABLE;
+ int use_siar;
+
+ if (TRAP(regs) != 0xf00)
+ use_siar = 0;
+ else if ((ppmu->flags & PPMU_NO_CONT_SAMPLING) && !marked)
+ use_siar = 0;
+ else
+ use_siar = 1;
+
+ regs->dsisr = mmcra;
+ regs->result = use_siar;
}
/*
@@ -1342,18 +1351,12 @@ unsigned long perf_misc_flags(struct pt_
*/
unsigned long perf_instruction_pointer(struct pt_regs *regs)
{
- unsigned long mmcra = regs->dsisr;
+ unsigned long use_siar = regs->result;
- /* Not a PMU interrupt */
- if (TRAP(regs) != 0xf00)
- return regs->nip;
-
- /* Processor doesn't support sampling non marked events */
- if ((ppmu->flags & PPMU_NO_CONT_SAMPLING) &&
- !(mmcra & MMCRA_SAMPLE_ENABLE))
+ if (use_siar)
+ return mfspr(SPRN_SIAR) + perf_ip_adjust(regs);
+ else
return regs->nip;
-
- return mfspr(SPRN_SIAR) + perf_ip_adjust(regs);
}
static bool pmc_overflow(unsigned long val)
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