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@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: paulus@samba.org
Cc: eranian@google.com
Cc: robert.richter@amd.com
Cc: fweisbec@gmail.com
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

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 (file)
--- 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;