From 24cc12b17679f8e9046746f92fd377f589efc163 Mon Sep 17 00:00:00 2001 From: Takao Indoh Date: Wed, 4 Nov 2015 14:22:32 +0900 Subject: [PATCH] perf/x86/intel/pt: Add interface to stop Intel PT logging This patch add a function for external components to stop Intel PT. Basically this function is used when kernel panic occurs. When it is called, the intel_pt driver disables Intel PT and saves its registers using pt_event_stop(), which is also used by pmu.stop handler. This function stops Intel PT on the CPU where it is working, therefore users of it need to call it for each CPU to stop all logging. Signed-off-by: Takao Indoh Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: H.Peter Anvin Cc: Jiri Olsa Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: Vivek Goyal Link: http://lkml.kernel.org/r/1446614553-6072-2-git-send-email-indou.takao@jp.fujitsu.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/intel_pt.h | 10 ++++++++++ arch/x86/kernel/cpu/perf_event_intel_pt.c | 9 +++++++++ 2 files changed, 19 insertions(+) create mode 100644 arch/x86/include/asm/intel_pt.h diff --git a/arch/x86/include/asm/intel_pt.h b/arch/x86/include/asm/intel_pt.h new file mode 100644 index 0000000..e1a4117 --- /dev/null +++ b/arch/x86/include/asm/intel_pt.h @@ -0,0 +1,10 @@ +#ifndef _ASM_X86_INTEL_PT_H +#define _ASM_X86_INTEL_PT_H + +#if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_INTEL) +void cpu_emergency_stop_pt(void); +#else +static inline void cpu_emergency_stop_pt(void) {} +#endif + +#endif /* _ASM_X86_INTEL_PT_H */ diff --git a/arch/x86/kernel/cpu/perf_event_intel_pt.c b/arch/x86/kernel/cpu/perf_event_intel_pt.c index 868e119..c0bbd10 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_pt.c +++ b/arch/x86/kernel/cpu/perf_event_intel_pt.c @@ -27,6 +27,7 @@ #include #include #include +#include #include "perf_event.h" #include "intel_pt.h" @@ -1122,6 +1123,14 @@ static int pt_event_init(struct perf_event *event) return 0; } +void cpu_emergency_stop_pt(void) +{ + struct pt *pt = this_cpu_ptr(&pt_ctx); + + if (pt->handle.event) + pt_event_stop(pt->handle.event, PERF_EF_UPDATE); +} + static __init int pt_init(void) { int ret, cpu, prior_warn = 0; -- 2.7.4