diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2012-06-08 14:50:50 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-07-05 21:55:57 +0200 |
| commit | c93dc84cbe32435be3ffa2fbde355eff94955c32 (patch) | |
| tree | b650cfcea486aa0dd1612f187156c7b84fb97661 /arch/x86/kernel/cpu/perf_event_intel.c | |
| parent | f285f92f7e4c9af20149130c8fd5027131b39b0e (diff) | |
perf/x86: Add a microcode revision check for SNB-PEBS
Recent Intel microcode resolved the SNB-PEBS issues, so conditionally
enable PEBS on SNB hardware depending on the microcode revision.
Thanks to Stephane for figuring out the various microcode revisions.
Suggested-by: Stephane Eranian <eranian@google.com>
Acked-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-v3672ziwh9damwqwh1uz3krm@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/cpu/perf_event_intel.c')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel.c | 51 |
1 files changed, 48 insertions, 3 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c index 2e9444c8014..5fdedb4bc3f 100644 --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -1712,11 +1712,56 @@ static __init void intel_clovertown_quirk(void) x86_pmu.pebs_constraints = NULL; } +static int intel_snb_pebs_broken(int cpu) +{ + u32 rev = UINT_MAX; /* default to broken for unknown models */ + + switch (cpu_data(cpu).x86_model) { + case 42: /* SNB */ + rev = 0x28; + break; + + case 45: /* SNB-EP */ + switch (cpu_data(cpu).x86_mask) { + case 6: rev = 0x618; break; + case 7: rev = 0x70c; break; + } + } + + return (cpu_data(cpu).microcode < rev); +} + +static void intel_snb_check_microcode(void) +{ + int pebs_broken = 0; + int cpu; + + get_online_cpus(); + for_each_online_cpu(cpu) { + if ((pebs_broken = intel_snb_pebs_broken(cpu))) + break; + } + put_online_cpus(); + + if (pebs_broken == x86_pmu.pebs_broken) + return; + + /* + * Serialized by the microcode lock.. + */ + if (x86_pmu.pebs_broken) { + pr_info("PEBS enabled due to microcode update\n"); + x86_pmu.pebs_broken = 0; + } else { + pr_info("PEBS disabled due to CPU errata, please upgrade microcode\n"); + x86_pmu.pebs_broken = 1; + } +} + static __init void intel_sandybridge_quirk(void) { - printk(KERN_WARNING "PEBS disabled due to CPU errata.\n"); - x86_pmu.pebs = 0; - x86_pmu.pebs_constraints = NULL; + x86_pmu.check_microcode = intel_snb_check_microcode; + intel_snb_check_microcode(); } static const struct { int id; char *name; } intel_arch_events_map[] __initconst = { |