From 53b25335dd60981ad608da7890420898a34469a6 Mon Sep 17 00:00:00 2001 From: Vince Weaver Date: Fri, 16 May 2014 17:12:12 -0400 Subject: [PATCH] perf: Disable sampled events if no PMU interrupt Add common code to generate -ENOTSUPP at event creation time if an architecture attempts to create a sampled event and PERF_PMU_NO_INTERRUPT is set. This adds a new pmu->capabilities flag. Initially we only support PERF_PMU_NO_INTERRUPT (to indicate a PMU has no support for generating hardware interrupts) but there are other capabilities that can be added later. Signed-off-by: Vince Weaver Acked-by: Will Deacon [peterz: rename to PERF_PMU_CAP_* and moved the pmu::capabilities word into a hole] Signed-off-by: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Linus Torvalds Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1405161708060.11099@vincent-weaver-1.umelst.maine.edu Signed-off-by: Ingo Molnar Signed-off-by: Ingo Molnar --- include/linux/perf_event.h | 10 ++++++++++ kernel/events/core.c | 7 +++++++ 2 files changed, 17 insertions(+) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index af6dcf1d9e47..267c8f37012c 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -166,6 +166,11 @@ struct perf_event; */ #define PERF_EVENT_TXN 0x1 +/** + * pmu::capabilities flags + */ +#define PERF_PMU_CAP_NO_INTERRUPT 0x01 + /** * struct pmu - generic performance monitoring unit */ @@ -178,6 +183,11 @@ struct pmu { const char *name; int type; + /* + * various common per-pmu feature flags + */ + int capabilities; + int * __percpu pmu_disable_count; struct perf_cpu_context * __percpu pmu_cpu_context; int task_ctx_nr; diff --git a/kernel/events/core.c b/kernel/events/core.c index a62d142ad498..e9ef0c6646af 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7120,6 +7120,13 @@ SYSCALL_DEFINE5(perf_event_open, } } + if (is_sampling_event(event)) { + if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) { + err = -ENOTSUPP; + goto err_alloc; + } + } + account_event(event); /*