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authorLinus Torvalds <torvalds@linux-foundation.org>2013-03-17 15:44:43 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-03-20 12:58:52 -0700
commitfe204aa40cedb6c34c5865be223da8f77d6a1545 (patch)
tree5647c84f0f024d6d4cf6c39498e8989a3b4a1373 /arch
parent87a42f27adef5e88b8907edbc168de1380e7129e (diff)
perf,x86: fix wrmsr_on_cpu() warning on suspend/resume
commit 2a6e06b2aed6995af401dcd4feb5e79a0c7ea554 upstream. Commit 1d9d8639c063 ("perf,x86: fix kernel crash with PEBS/BTS after suspend/resume") fixed a crash when doing PEBS performance profiling after resuming, but in using init_debug_store_on_cpu() to restore the DS_AREA mtrr it also resulted in a new WARN_ON() triggering. init_debug_store_on_cpu() uses "wrmsr_on_cpu()", which in turn uses CPU cross-calls to do the MSR update. Which is not really valid at the early resume stage, and the warning is quite reasonable. Now, it all happens to _work_, for the simple reason that smp_call_function_single() ends up just doing the call directly on the CPU when the CPU number matches, but we really should just do the wrmsr() directly instead. This duplicates the wrmsr() logic, but hopefully we can just remove the wrmsr_on_cpu() version eventually. Reported-and-tested-by: Parag Warudkar <parag.lkml@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/perf_event_intel_ds.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index cf82ee55ef4b..c81d1f89df0a 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -756,10 +756,12 @@ static void intel_ds_init(void)
void perf_restore_debug_store(void)
{
+ struct debug_store *ds = __this_cpu_read(cpu_hw_events.ds);
+
if (!x86_pmu.bts && !x86_pmu.pebs)
return;
- init_debug_store_on_cpu(smp_processor_id());
+ wrmsrl(MSR_IA32_DS_AREA, (unsigned long)ds);
}
#else /* CONFIG_CPU_SUP_INTEL */