arm: perf: treat PMUs as CPU affine

[sfrench/cifs-2.6.git] / arch / arm / kernel / perf_event.c

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index 4a86a0133ac30cab95b9a461636b7961f6bd86e2..9b536be74f7bbb731cb1c8c56681ca774d8d1f7d 100644 (file)
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -11,6 +11,7 @@
  */
 #define pr_fmt(fmt) "hw perfevents: " fmt
 
+#include <linux/cpumask.h>
 #include <linux/kernel.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
@@ -229,6 +230,10 @@ armpmu_add(struct perf_event *event, int flags)
        int idx;
        int err = 0;
 
+       /* An event following a process won't be stopped earlier */
+       if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
+               return -ENOENT;
+
        perf_pmu_disable(event->pmu);
 
        /* If we don't have a space for the counter then finish early. */
@@ -454,6 +459,17 @@ static int armpmu_event_init(struct perf_event *event)
        int err = 0;
        atomic_t *active_events = &armpmu->active_events;
 
+       /*
+        * Reject CPU-affine events for CPUs that are of a different class to
+        * that which this PMU handles. Process-following events (where
+        * event->cpu == -1) can be migrated between CPUs, and thus we have to
+        * reject them later (in armpmu_add) if they're scheduled on a
+        * different class of CPU.
+        */
+       if (event->cpu != -1 &&
+               !cpumask_test_cpu(event->cpu, &armpmu->supported_cpus))
+               return -ENOENT;
+
        /* does not support taken branch sampling */
        if (has_branch_stack(event))
                return -EOPNOTSUPP;
@@ -489,6 +505,10 @@ static void armpmu_enable(struct pmu *pmu)
        struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
        int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events);
 
+       /* For task-bound events we may be called on other CPUs */
+       if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
+               return;
+
        if (enabled)
                armpmu->start(armpmu);
 }
@@ -496,6 +516,11 @@ static void armpmu_enable(struct pmu *pmu)
 static void armpmu_disable(struct pmu *pmu)
 {
        struct arm_pmu *armpmu = to_arm_pmu(pmu);
+
+       /* For task-bound events we may be called on other CPUs */
+       if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
+               return;
+
        armpmu->stop(armpmu);
 }