[tip:perf/pebs] perf, x86: Fix PEBS enable/disable vs cpuc->enabled

tip-bot for Peter Zijlstra
2010-03-10T13:23:28Z

Commit-ID: 4807e3d5dc7bb7057dd6ca3abb09f3da2eb8c323
Gitweb: http://git.kernel.org/tip/4807e3d5dc7bb7057dd6ca3abb09f3da2eb8c323
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Sat, 6 Mar 2010 13:47:07 +0100
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 10 Mar 2010 13:23:36 +0100

perf, x86: Fix PEBS enable/disable vs cpuc->enabled

We should never call ->enable with the pmu enabled, and we _can_ have
->disable called with the pmu enabled.

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>
---
arch/x86/kernel/cpu/perf_event_intel_ds.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 66c6962..9ad0e67 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -338,7 +338,7 @@ static void intel_pmu_pebs_enable(struct perf_event *event)
hwc->config &= ~ARCH_PERFMON_EVENTSEL_INT;

val |= 1ULL << hwc->idx;
- wrmsrl(MSR_IA32_PEBS_ENABLE, val);
+ WARN_ON_ONCE(cpuc->enabled);

if (x86_pmu.intel_cap.pebs_trap)
intel_pmu_lbr_enable(event);
@@ -351,7 +351,8 @@ static void intel_pmu_pebs_disable(struct perf_event *event)
u64 val = cpuc->pebs_enabled;

val &= ~(1ULL << hwc->idx);
- wrmsrl(MSR_IA32_PEBS_ENABLE, val);
+ if (cpuc->enabled)
+ wrmsrl(MSR_IA32_PEBS_ENABLE, val);

hwc->config |= ARCH_PERFMON_EVENTSEL_INT;