From a3ef2229c94ff70998724cb64b9cb4c77db9e950 Mon Sep 17 00:00:00 2001 From: Markus Metzger Date: Fri, 14 Feb 2014 16:44:08 -0800 Subject: perf, nmi: Fix unknown NMI warning When using BTS on Core i7-4*, I get the below kernel warning. $ perf record -c 1 -e branches:u ls Message from syslogd@labpc1501 at Nov 11 15:49:25 ... kernel:[ 438.317893] Uhhuh. NMI received for unknown reason 31 on CPU 2. Message from syslogd@labpc1501 at Nov 11 15:49:25 ... kernel:[ 438.317920] Do you have a strange power saving mode enabled? Message from syslogd@labpc1501 at Nov 11 15:49:25 ... kernel:[ 438.317945] Dazed and confused, but trying to continue Make intel_pmu_handle_irq() take the full exit path when returning early. Cc: eranian@google.com Cc: peterz@infradead.org Cc: mingo@kernel.org Signed-off-by: Markus Metzger Signed-off-by: Andi Kleen Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1392425048-5309-1-git-send-email-andi@firstfloor.org Signed-off-by: Thomas Gleixner --- arch/x86/kernel/cpu/perf_event_intel.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'arch/x86/kernel/cpu/perf_event_intel.c') diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c index 0fa4f242f05..698ae77d6f1 100644 --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -1361,10 +1361,8 @@ static int intel_pmu_handle_irq(struct pt_regs *regs) intel_pmu_disable_all(); handled = intel_pmu_drain_bts_buffer(); status = intel_pmu_get_status(); - if (!status) { - intel_pmu_enable_all(0); - return handled; - } + if (!status) + goto done; loops = 0; again: -- cgit v1.2.3-70-g09d2 From c9b08884c9c98929ec2d8abafd78e89062d01ee7 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 3 Feb 2014 14:29:03 +0100 Subject: perf/x86: Correctly use FEATURE_PDCM The current code simply assumes Intel Arch PerfMon v2+ to have the IA32_PERF_CAPABILITIES MSR; the SDM specifies that we should check CPUID[1].ECX[15] (aka, FEATURE_PDCM) instead. This was found by KVM which implements v2+ but didn't provide the capabilities MSR. Change the code to DTRT; KVM will also implement the MSR and return 0. Cc: pbonzini@redhat.com Reported-by: "Michael S. Tsirkin" Suggested-by: Eduardo Habkost Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20140203132903.GI8874@twins.programming.kicks-ass.net Signed-off-by: Thomas Gleixner --- arch/x86/kernel/cpu/perf_event_intel.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'arch/x86/kernel/cpu/perf_event_intel.c') diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c index 698ae77d6f1..aa333d96688 100644 --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -2308,10 +2308,7 @@ __init int intel_pmu_init(void) if (version > 1) x86_pmu.num_counters_fixed = max((int)edx.split.num_counters_fixed, 3); - /* - * v2 and above have a perf capabilities MSR - */ - if (version > 1) { + if (boot_cpu_has(X86_FEATURE_PDCM)) { u64 capabilities; rdmsrl(MSR_IA32_PERF_CAPABILITIES, capabilities); -- cgit v1.2.3-70-g09d2