diff options
| author | Stephane Eranian <eranian@google.com> | 2013-03-15 14:26:07 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-03-15 09:26:35 -0700 |
| commit | 1d9d8639c063caf6efc2447f5f26aa637f844ff6 (patch) | |
| tree | ab9c24ccfd8b464211b393ac8ae9cd6b964e9df3 /arch/x86 | |
| parent | a2362d24764a4e9a3187fc46b14e1d2cd0657700 (diff) | |
perf,x86: fix kernel crash with PEBS/BTS after suspend/resume
This patch fixes a kernel crash when using precise sampling (PEBS)
after a suspend/resume. Turns out the CPU notifier code is not invoked
on CPU0 (BP). Therefore, the DS_AREA (used by PEBS) is not restored properly
by the kernel and keeps it power-on/resume value of 0 causing any PEBS
measurement to crash when running on CPU0.
The workaround is to add a hook in the actual resume code to restore
the DS Area MSR value. It is invoked for all CPUS. So for all but CPU0,
the DS_AREA will be restored twice but this is harmless.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel_ds.c | 8 | ||||
| -rw-r--r-- | arch/x86/power/cpu.c | 2 |
2 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c index 826054a4f2ee..0e9bdd3cb01e 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_ds.c +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c @@ -729,3 +729,11 @@ void intel_ds_init(void) } } } + +void perf_restore_debug_store(void) +{ + if (!x86_pmu.bts && !x86_pmu.pebs) + return; + + init_debug_store_on_cpu(smp_processor_id()); +} diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c index 120cee1c3f8d..3c68768d7a75 100644 --- a/arch/x86/power/cpu.c +++ b/arch/x86/power/cpu.c @@ -11,6 +11,7 @@ #include <linux/suspend.h> #include <linux/export.h> #include <linux/smp.h> +#include <linux/perf_event.h> #include <asm/pgtable.h> #include <asm/proto.h> @@ -228,6 +229,7 @@ static void __restore_processor_state(struct saved_context *ctxt) do_fpu_end(); x86_platform.restore_sched_clock_state(); mtrr_bp_restore(); + perf_restore_debug_store(); } /* Needed by apm.c */ |