From e6878835ac4794f25385522d29c634b7bbb7cca9 Mon Sep 17 00:00:00 2001
From: "sukadev@linux.vnet.ibm.com" <sukadev@linux.vnet.ibm.com>
Date: Tue, 18 Sep 2012 20:56:11 +0000
Subject: 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>
---
 arch/powerpc/include/asm/perf_event_server.h | 1 +
 arch/powerpc/include/asm/reg.h               | 4 ++++
 2 files changed, 5 insertions(+)

(limited to 'arch/powerpc/include/asm')

diff --git a/arch/powerpc/include/asm/perf_event_server.h b/arch/powerpc/include/asm/perf_event_server.h
index 078019b..9710be3 100644
--- a/arch/powerpc/include/asm/perf_event_server.h
+++ b/arch/powerpc/include/asm/perf_event_server.h
@@ -49,6 +49,7 @@ struct power_pmu {
 #define PPMU_ALT_SIPR		2	/* uses alternate posn for SIPR/HV */
 #define PPMU_NO_SIPR		4	/* no SIPR/HV in MMCRA at all */
 #define PPMU_NO_CONT_SAMPLING	8	/* no continuous sampling */
+#define PPMU_SIAR_VALID		16	/* Processor has SIAR Valid bit */
 
 /*
  * Values for flags to get_alternatives()
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
-- 
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