arm64: perf: add support for percpu pmu interrupt

Add support for irq registration when pmu interrupt is percpu.
Signed-off-by: Vinayak Kale <vkale@apm.com>
Signed-off-by: Tuan Phan <tphan@apm.com>
[will: tidied up cross-calling to pass &irq]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/kernel/perf_event.c

@@ -22,6 +22,7 @@
 
 #include <linux/bitmap.h>
 #include <linux/interrupt.h>
+#include <linux/irq.h>
 #include <linux/kernel.h>
 #include <linux/export.h>
 #include <linux/perf_event.h>
@@ -362,27 +363,54 @@ validate_group(struct perf_event *event)
 	return 0;
 }
 
+static void
+armpmu_disable_percpu_irq(void *data)
+{
+	unsigned int irq = *(unsigned int *)data;
+	disable_percpu_irq(irq);
+}
+
 static void
 armpmu_release_hardware(struct arm_pmu *armpmu)
 {
-	int i, irq, irqs;
+	int irq;
+	unsigned int i, irqs;
 	struct platform_device *pmu_device = armpmu->plat_device;
 
 	irqs = min(pmu_device->num_resources, num_possible_cpus());
+	if (!irqs)
+		return;
+
+	irq = platform_get_irq(pmu_device, 0);
+	if (irq <= 0)
+		return;
 
+	if (irq_is_percpu(irq)) {
+		on_each_cpu(armpmu_disable_percpu_irq, &irq, 1);
+		free_percpu_irq(irq, &cpu_hw_events);
+	} else {
 		for (i = 0; i < irqs; ++i) {
 			if (!cpumask_test_and_clear_cpu(i, &armpmu->active_irqs))
 				continue;
 			irq = platform_get_irq(pmu_device, i);
-		if (irq >= 0)
+			if (irq > 0)
 				free_irq(irq, armpmu);
 		}
+	}
+}
+
+static void
+armpmu_enable_percpu_irq(void *data)
+{
+	unsigned int irq = *(unsigned int *)data;
+	enable_percpu_irq(irq, IRQ_TYPE_NONE);
 }
 
 static int
 armpmu_reserve_hardware(struct arm_pmu *armpmu)
 {
-	int i, err, irq, irqs;
+	int err, irq;
+	unsigned int i, irqs;
 	struct platform_device *pmu_device = armpmu->plat_device;
 
 	if (!pmu_device) {
@@ -391,15 +419,34 @@ armpmu_reserve_hardware(struct arm_pmu *armpmu)
 	}
 
 	irqs = min(pmu_device->num_resources, num_possible_cpus());
-	if (irqs < 1) {
+	if (!irqs) {
 		pr_err("no irqs for PMUs defined\n");
 		return -ENODEV;
 	}
 
+	irq = platform_get_irq(pmu_device, 0);
+	if (irq <= 0) {
+		pr_err("failed to get valid irq for PMU device\n");
+		return -ENODEV;
+	}
+
+	if (irq_is_percpu(irq)) {
+		err = request_percpu_irq(irq, armpmu->handle_irq,
+				"arm-pmu", &cpu_hw_events);
+
+		if (err) {
+			pr_err("unable to request percpu IRQ%d for ARM PMU counters\n",
+					irq);
+			armpmu_release_hardware(armpmu);
+			return err;
+		}
+
+		on_each_cpu(armpmu_enable_percpu_irq, &irq, 1);
+	} else {
 		for (i = 0; i < irqs; ++i) {
 			err = 0;
 			irq = platform_get_irq(pmu_device, i);
-		if (irq < 0)
+			if (irq <= 0)
 				continue;
 
 			/*
@@ -425,6 +472,7 @@ armpmu_reserve_hardware(struct arm_pmu *armpmu)
 
 			cpumask_set_cpu(i, &armpmu->active_irqs);
 		}
+	}
 
 	return 0;
 }