1 files changed, 50 insertions, 103 deletions

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index e984653b93aa..a1dfe895cb1d 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -352,37 +352,6 @@ static irqreturn_t armpmu_dispatch_irq(int irq, void *dev)
 	return ret;
 }
 
-static void
-armpmu_release_hardware(struct arm_pmu *armpmu)
-{
-	armpmu->free_irq(armpmu);
-}
-
-static int
-armpmu_reserve_hardware(struct arm_pmu *armpmu)
-{
-	int err = armpmu->request_irq(armpmu, armpmu_dispatch_irq);
-	if (err) {
-		armpmu_release_hardware(armpmu);
-		return err;
-	}
-
-	return 0;
-}
-
-static void
-hw_perf_event_destroy(struct perf_event *event)
-{
-	struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
-	atomic_t *active_events	 = &armpmu->active_events;
-	struct mutex *pmu_reserve_mutex = &armpmu->reserve_mutex;
-
-	if (atomic_dec_and_mutex_lock(active_events, pmu_reserve_mutex)) {
-		armpmu_release_hardware(armpmu);
-		mutex_unlock(pmu_reserve_mutex);
-	}
-}
-
 static int
 event_requires_mode_exclusion(struct perf_event_attr *attr)
 {
@@ -455,8 +424,6 @@ __hw_perf_event_init(struct perf_event *event)
 static int armpmu_event_init(struct perf_event *event)
 {
 	struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
-	int err = 0;
-	atomic_t *active_events = &armpmu->active_events;
 
 	/*
 	 * Reject CPU-affine events for CPUs that are of a different class to
@@ -476,26 +443,7 @@ static int armpmu_event_init(struct perf_event *event)
 	if (armpmu->map_event(event) == -ENOENT)
 		return -ENOENT;
 
-	event->destroy = hw_perf_event_destroy;
-
-	if (!atomic_inc_not_zero(active_events)) {
-		mutex_lock(&armpmu->reserve_mutex);
-		if (atomic_read(active_events) == 0)
-			err = armpmu_reserve_hardware(armpmu);
-
-		if (!err)
-			atomic_inc(active_events);
-		mutex_unlock(&armpmu->reserve_mutex);
-	}
-
-	if (err)
-		return err;
-
-	err = __hw_perf_event_init(event);
-	if (err)
-		hw_perf_event_destroy(event);
-
-	return err;
+	return __hw_perf_event_init(event);
 }
 
 static void armpmu_enable(struct pmu *pmu)
@@ -555,9 +503,6 @@ static struct attribute_group armpmu_common_attr_group = {
 
 static void armpmu_init(struct arm_pmu *armpmu)
 {
-	atomic_set(&armpmu->active_events, 0);
-	mutex_init(&armpmu->reserve_mutex);
-
 	armpmu->pmu = (struct pmu) {
 		.pmu_enable	= armpmu_enable,
 		.pmu_disable	= armpmu_disable,
@@ -601,21 +546,7 @@ int perf_num_counters(void)
 }
 EXPORT_SYMBOL_GPL(perf_num_counters);
 
-static void cpu_pmu_enable_percpu_irq(void *data)
-{
-	int irq = *(int *)data;
-
-	enable_percpu_irq(irq, IRQ_TYPE_NONE);
-}
-
-static void cpu_pmu_disable_percpu_irq(void *data)
-{
-	int irq = *(int *)data;
-
-	disable_percpu_irq(irq);
-}
-
-static void cpu_pmu_free_irq(struct arm_pmu *cpu_pmu)
+static void cpu_pmu_free_irqs(struct arm_pmu *cpu_pmu)
 {
 	int cpu;
 	struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;
@@ -626,10 +557,7 @@ static void cpu_pmu_free_irq(struct arm_pmu *cpu_pmu)
 			continue;
 
 		if (irq_is_percpu(irq)) {
-			on_each_cpu_mask(&cpu_pmu->supported_cpus,
-					 cpu_pmu_disable_percpu_irq, &irq, 1);
 			free_percpu_irq(irq, &hw_events->percpu_pmu);
-
 			break;
 		}
 
@@ -640,7 +568,7 @@ static void cpu_pmu_free_irq(struct arm_pmu *cpu_pmu)
 	}
 }
 
-static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
+static int cpu_pmu_request_irqs(struct arm_pmu *cpu_pmu, irq_handler_t handler)
 {
 	int cpu, err;
 	struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;
@@ -656,25 +584,9 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
 			if (err) {
 				pr_err("unable to request IRQ%d for ARM PMU counters\n",
 					irq);
-				return err;
 			}
 
-			on_each_cpu_mask(&cpu_pmu->supported_cpus,
-					 cpu_pmu_enable_percpu_irq, &irq, 1);
-
-			break;
-		}
-
-		/*
-		 * If we have a single PMU interrupt that we can't shift,
-		 * assume that we're running on a uniprocessor machine and
-		 * continue. Otherwise, continue without this interrupt.
-		 */
-		if (irq_set_affinity(irq, cpumask_of(cpu)) &&
-		    num_possible_cpus() > 1) {
-			pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",
-				irq, cpu);
-			continue;
+			return err;
 		}
 
 		err = request_irq(irq, handler,
@@ -692,6 +604,12 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
 	return 0;
 }
 
+static int armpmu_get_cpu_irq(struct arm_pmu *pmu, int cpu)
+{
+	struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
+	return per_cpu(hw_events->irq, cpu);
+}
+
 /*
  * PMU hardware loses all context when a CPU goes offline.
  * When a CPU is hotplugged back in, since some hardware registers are
@@ -701,11 +619,42 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
 static int arm_perf_starting_cpu(unsigned int cpu, struct hlist_node *node)
 {
 	struct arm_pmu *pmu = hlist_entry_safe(node, struct arm_pmu, node);
+	int irq;
 
 	if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
 		return 0;
 	if (pmu->reset)
 		pmu->reset(pmu);
+
+	irq = armpmu_get_cpu_irq(pmu, cpu);
+	if (irq) {
+		if (irq_is_percpu(irq)) {
+			enable_percpu_irq(irq, IRQ_TYPE_NONE);
+			return 0;
+		}
+
+		if (irq_force_affinity(irq, cpumask_of(cpu)) &&
+		    num_possible_cpus() > 1) {
+			pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",
+				irq, cpu);
+		}
+	}
+
+	return 0;
+}
+
+static int arm_perf_teardown_cpu(unsigned int cpu, struct hlist_node *node)
+{
+	struct arm_pmu *pmu = hlist_entry_safe(node, struct arm_pmu, node);
+	int irq;
+
+	if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
+		return 0;
+
+	irq = armpmu_get_cpu_irq(pmu, cpu);
+	if (irq && irq_is_percpu(irq))
+		disable_percpu_irq(irq);
+
 	return 0;
 }
 
@@ -811,8 +760,12 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
 {
 	int err;
 
-	err = cpuhp_state_add_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
-					       &cpu_pmu->node);
+	err = cpu_pmu_request_irqs(cpu_pmu, armpmu_dispatch_irq);
+	if (err)
+		goto out;
+
+	err = cpuhp_state_add_instance(CPUHP_AP_PERF_ARM_STARTING,
+				       &cpu_pmu->node);
 	if (err)
 		goto out;
 
@@ -820,14 +773,6 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
 	if (err)
 		goto out_unregister;
 
-	cpu_pmu->request_irq	= cpu_pmu_request_irq;
-	cpu_pmu->free_irq	= cpu_pmu_free_irq;
-
-	/* Ensure the PMU has sane values out of reset. */
-	if (cpu_pmu->reset)
-		on_each_cpu_mask(&cpu_pmu->supported_cpus, cpu_pmu->reset,
-			 cpu_pmu, 1);
-
 	/*
 	 * This is a CPU PMU potentially in a heterogeneous configuration (e.g.
 	 * big.LITTLE). This is not an uncore PMU, and we have taken ctx
@@ -842,6 +787,7 @@ out_unregister:
 	cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
 					    &cpu_pmu->node);
 out:
+	cpu_pmu_free_irqs(cpu_pmu);
 	return err;
 }
 
@@ -1122,7 +1068,8 @@ static int arm_pmu_hp_init(void)
 
 	ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_STARTING,
 				      "perf/arm/pmu:starting",
-				      arm_perf_starting_cpu, NULL);
+				      arm_perf_starting_cpu,
+				      arm_perf_teardown_cpu);
 	if (ret)
 		pr_err("CPU hotplug notifier for ARM PMU could not be registered: %d\n",
 		       ret);