3 files changed, 38 insertions, 3 deletions

diff --git a/arch/arm/include/asm/pmu.h b/arch/arm/include/asm/pmu.h
index 675e4ab79f68..ecad26e7a68f 100644
--- a/arch/arm/include/asm/pmu.h
+++ b/arch/arm/include/asm/pmu.h
@@ -92,6 +92,7 @@ struct pmu_hw_events {
 struct arm_pmu {
         struct pmu      pmu;
         cpumask_t       active_irqs;
+        cpumask_t       supported_cpus;
         int             *irq_affinity;
         char            *name;
         irqreturn_t     (*handle_irq)(int irq_num, void *dev);
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index 4a86a0133ac3..9b536be74f7b 100644
--- 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);
 }
 
diff --git a/arch/arm/kernel/perf_event_cpu.c b/arch/arm/kernel/perf_event_cpu.c
index 2a9003ef6db3..9602d31aae03 100644
--- a/arch/arm/kernel/perf_event_cpu.c
+++ b/arch/arm/kernel/perf_event_cpu.c
@@ -179,11 +179,15 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
 static int cpu_pmu_notify(struct notifier_block *b, unsigned long action,
                           void *hcpu)
 {
+        int cpu = (unsigned long)hcpu;
         struct arm_pmu *pmu = container_of(b, struct arm_pmu, hotplug_nb);
 
         if ((action & ~CPU_TASKS_FROZEN) != CPU_STARTING)
                 return NOTIFY_DONE;
 
+        if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
+                return NOTIFY_DONE;
+
         if (pmu->reset)
                 pmu->reset(pmu);
         else
@@ -219,7 +223,8 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
 
         /* Ensure the PMU has sane values out of reset. */
         if (cpu_pmu->reset)
-                on_each_cpu(cpu_pmu->reset, cpu_pmu, 1);
+                on_each_cpu_mask(&cpu_pmu->supported_cpus, cpu_pmu->reset,
+                         cpu_pmu, 1);
 
         /* If no interrupts available, set the corresponding capability flag */
         if (!platform_get_irq(cpu_pmu->plat_device, 0))
@@ -334,12 +339,15 @@ static int of_pmu_irq_cfg(struct arm_pmu *pmu)
                 }
 
                 irqs[i] = cpu;
+                cpumask_set_cpu(cpu, &pmu->supported_cpus);
         }
 
-        if (i == pdev->num_resources)
+        if (i == pdev->num_resources) {
                 pmu->irq_affinity = irqs;
-        else
+        } else {
                 kfree(irqs);
+                cpumask_setall(&pmu->supported_cpus);
+        }
 
         return 0;
 }
@@ -374,6 +382,7 @@ static int cpu_pmu_device_probe(struct platform_device *pdev)
                         ret = init_fn(pmu);
         } else {
                 ret = probe_current_pmu(pmu);
+                cpumask_setall(&pmu->supported_cpus);
         }
 
         if (ret) {