[tip:perf/pebs] perf, x86: Fix silly bug in intel_pmu_pebs_{enable,disable}

[tip-bot for Peter Zijlstra]

Commit-ID:  ad0e6cfe2a2a61d7b5530188e571d508146cb43b
Gitweb:     http://git.kernel.org/tip/ad0e6cfe2a2a61d7b5530188e571d508146cb43b
Author:     Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Sat, 6 Mar 2010 19:49:06 +0100
Committer:  Ingo Molnar <mingo@xxxxxxx>
CommitDate: Wed, 10 Mar 2010 13:23:38 +0100

perf, x86: Fix silly bug in intel_pmu_pebs_{enable,disable}

We need to use the actual cpuc->pebs_enabled value, not a local copy for
the changes to take effect.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxx>
Cc: paulus@xxxxxxxxx
Cc: eranian@xxxxxxxxxx
Cc: robert.richter@xxxxxxx
Cc: fweisbec@xxxxxxxxx
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
 arch/x86/kernel/cpu/perf_event_intel_ds.c |    8 +++-----
 1 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index b4680da..2423694 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -333,11 +333,10 @@ static void intel_pmu_pebs_enable(struct perf_event *event)
 {
 	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
 	struct hw_perf_event *hwc = &event->hw;
-	u64 val = cpuc->pebs_enabled;
 
 	hwc->config &= ~ARCH_PERFMON_EVENTSEL_INT;
 
-	val |= 1ULL << hwc->idx;
+	cpuc->pebs_enabled |= 1ULL << hwc->idx;
 	WARN_ON_ONCE(cpuc->enabled);
 
 	if (x86_pmu.intel_cap.pebs_trap)
@@ -348,11 +347,10 @@ static void intel_pmu_pebs_disable(struct perf_event *event)
 {
 	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
 	struct hw_perf_event *hwc = &event->hw;
-	u64 val = cpuc->pebs_enabled;
 
-	val &= ~(1ULL << hwc->idx);
+	cpuc->pebs_enabled &= ~(1ULL << hwc->idx);
 	if (cpuc->enabled)
-		wrmsrl(MSR_IA32_PEBS_ENABLE, val);
+		wrmsrl(MSR_IA32_PEBS_ENABLE, cpuc->pebs_enabled);
 
 	hwc->config |= ARCH_PERFMON_EVENTSEL_INT;
 
--
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