powerpc/perf: Sample only if SIAR-Valid bit is set in P7+
powerpc/perf: Sample only if SIAR-Valid bit is set in P7+
On POWER7+ two new bits (mmcra[35] and mmcra[36]) indicate whether the
contents of SIAR and SDAR are valid.
For marked instructions on P7+, we must save the contents of SIAR and
SDAR registers only if these new bits are set.
This code/check for the SIAR-Valid bit is specific to P7+, so rather than
waste a CPU-feature bit use the PVR flag.
Note that Carl Love proposed a similar change for oprofile:
https://lkml.org/lkml/2012/6/22/309
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index a1096fb..d24c141 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -606,6 +606,10 @@
#define POWER6_MMCRA_SIPR 0x0000020000000000ULL
#define POWER6_MMCRA_THRM 0x00000020UL
#define POWER6_MMCRA_OTHER 0x0000000EUL
+
+#define POWER7P_MMCRA_SIAR_VALID 0x10000000 /* P7+ SIAR contents valid */
+#define POWER7P_MMCRA_SDAR_VALID 0x08000000 /* P7+ SDAR contents valid */
+
#define SPRN_PMC1 787
#define SPRN_PMC2 788
#define SPRN_PMC3 789