Merge branch 'for-rmk/perf' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux into devel-stable

There's quite a lot here, most of it from Mark Rutland, who has been
working on big.LITTLE PMU support for a while now. His work also brings
us significantly closer to moving the bulk of the CPU PMU driver out
into drivers/, where it can be shared with arm64.

As part of this work, there is a small patch to perf/core, which has
been Acked-by PeterZ and doesn't conflict with tip/perf/core at present.
I've kept that patch on a separate branch, merged in here, so that the
tip guys can pull it too if any unexpected issues crop up.

Please note that there is a conflict with mainline, since we remove
perf_event_cpu.c. The correct resolution is also to remove the file,
since the changes there are already reflected in the rework (and this
resolution is already included in linux-next).

arch/arm/include/asm/perf_event.h

···
 #define perf_misc_flags(regs)	perf_misc_flags(regs)
 #endif
 
+#define perf_arch_fetch_caller_regs(regs, __ip) { \
+	(regs)->ARM_pc = (__ip); \
+	(regs)->ARM_fp = (unsigned long) __builtin_frame_address(0); \
+	(regs)->ARM_sp = current_stack_pointer; \
+	(regs)->ARM_cpsr = SVC_MODE; \
+}
+
 #endif /* __ARM_PERF_EVENT_H__ */

arch/arm/include/asm/pmu.h

···
  *	interrupt and passed the address of the low level handler,
  *	and can be used to implement any platform specific handling
  *	before or after calling it.
- * @runtime_resume: an optional handler which will be called by the
- *	runtime PM framework following a call to pm_runtime_get().
- *	Note that if pm_runtime_get() is called more than once in
- *	succession this handler will only be called once.
- * @runtime_suspend: an optional handler which will be called by the
- *	runtime PM framework following a call to pm_runtime_put().
- *	Note that if pm_runtime_get() is called more than once in
- *	succession this handler will only be called following the
- *	final call to pm_runtime_put() that actually disables the
- *	hardware.
  */
 struct arm_pmu_platdata {
 	irqreturn_t (*handle_irq)(int irq, void *dev,
 				  irq_handler_t pmu_handler);
-	int (*runtime_resume)(struct device *dev);
-	int (*runtime_suspend)(struct device *dev);
 };
 
 #ifdef CONFIG_HW_PERF_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);
···
 };
 
 #define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu))
-
-extern const struct dev_pm_ops armpmu_dev_pm_ops;
 
 int armpmu_register(struct arm_pmu *armpmu, int type);
 
···
 
 #define XSCALE_PMU_PROBE(_version, _fn) \
 	PMU_PROBE(ARM_CPU_IMP_INTEL << 24 | _version, ARM_PMU_XSCALE_MASK, _fn)
+
+int arm_pmu_device_probe(struct platform_device *pdev,
+			 const struct of_device_id *of_table,
+			 const struct pmu_probe_info *probe_table);
 
 #endif /* CONFIG_HW_PERF_EVENTS */
 

arch/arm/kernel/Makefile

···
 obj-$(CONFIG_CPU_PJ4B)		+= pj4-cp0.o
 obj-$(CONFIG_IWMMXT)		+= iwmmxt.o
 obj-$(CONFIG_PERF_EVENTS)	+= perf_regs.o perf_callchain.o
-obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event.o perf_event_cpu.o
+obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event.o \
+				   perf_event_xscale.o perf_event_v6.o \
+				   perf_event_v7.o
 CFLAGS_pj4-cp0.o		:= -marm
 AFLAGS_iwmmxt.o			:= -Wa,-mcpu=iwmmxt
 obj-$(CONFIG_ARM_CPU_TOPOLOGY)  += topology.o

arch/arm/kernel/perf_event.c

···
  */
 #define pr_fmt(fmt) "hw perfevents: " fmt
 
+#include <linux/bitmap.h>
+#include <linux/cpumask.h>
+#include <linux/export.h>
 #include <linux/kernel.h>
+#include <linux/of.h>
 #include <linux/platform_device.h>
-#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
 #include <linux/irq.h>
 #include <linux/irqdesc.h>
 
+#include <asm/cputype.h>
 #include <asm/irq_regs.h>
 #include <asm/pmu.h>
 
···
 	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. */
···
 armpmu_release_hardware(struct arm_pmu *armpmu)
 {
 	armpmu->free_irq(armpmu);
-	pm_runtime_put_sync(&armpmu->plat_device->dev);
 }
 
 static int
 armpmu_reserve_hardware(struct arm_pmu *armpmu)
 {
-	int err;
-	struct platform_device *pmu_device = armpmu->plat_device;
-
-	if (!pmu_device)
-		return -ENODEV;
-
-	pm_runtime_get_sync(&pmu_device->dev);
-	err = armpmu->request_irq(armpmu, armpmu_dispatch_irq);
+	int err = armpmu->request_irq(armpmu, armpmu_dispatch_irq);
 	if (err) {
 		armpmu_release_hardware(armpmu);
 		return err;
···
 	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;
···
 	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);
 }
···
 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);
 }
 
-#ifdef CONFIG_PM
-static int armpmu_runtime_resume(struct device *dev)
+/*
+ * In heterogeneous systems, events are specific to a particular
+ * microarchitecture, and aren't suitable for another. Thus, only match CPUs of
+ * the same microarchitecture.
+ */
+static int armpmu_filter_match(struct perf_event *event)
 {
-	struct arm_pmu_platdata *plat = dev_get_platdata(dev);
-
-	if (plat && plat->runtime_resume)
-		return plat->runtime_resume(dev);
-
-	return 0;
+	struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
+	unsigned int cpu = smp_processor_id();
+	return cpumask_test_cpu(cpu, &armpmu->supported_cpus);
 }
-
-static int armpmu_runtime_suspend(struct device *dev)
-{
-	struct arm_pmu_platdata *plat = dev_get_platdata(dev);
-
-	if (plat && plat->runtime_suspend)
-		return plat->runtime_suspend(dev);
-
-	return 0;
-}
-#endif
-
-const struct dev_pm_ops armpmu_dev_pm_ops = {
-	SET_RUNTIME_PM_OPS(armpmu_runtime_suspend, armpmu_runtime_resume, NULL)
-};
 
 static void armpmu_init(struct arm_pmu *armpmu)
 {
···
 		.start		= armpmu_start,
 		.stop		= armpmu_stop,
 		.read		= armpmu_read,
+		.filter_match	= armpmu_filter_match,
 	};
 }
 
 int armpmu_register(struct arm_pmu *armpmu, int type)
 {
 	armpmu_init(armpmu);
-	pm_runtime_enable(&armpmu->plat_device->dev);
 	pr_info("enabled with %s PMU driver, %d counters available\n",
 			armpmu->name, armpmu->num_events);
 	return perf_pmu_register(&armpmu->pmu, armpmu->name, type);
 }
 
+/* Set at runtime when we know what CPU type we are. */
+static struct arm_pmu *__oprofile_cpu_pmu;
+
+/*
+ * Despite the names, these two functions are CPU-specific and are used
+ * by the OProfile/perf code.
+ */
+const char *perf_pmu_name(void)
+{
+	if (!__oprofile_cpu_pmu)
+		return NULL;
+
+	return __oprofile_cpu_pmu->name;
+}
+EXPORT_SYMBOL_GPL(perf_pmu_name);
+
+int perf_num_counters(void)
+{
+	int max_events = 0;
+
+	if (__oprofile_cpu_pmu != NULL)
+		max_events = __oprofile_cpu_pmu->num_events;
+
+	return max_events;
+}
+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)
+{
+	int i, irq, irqs;
+	struct platform_device *pmu_device = cpu_pmu->plat_device;
+	struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;
+
+	irqs = min(pmu_device->num_resources, num_possible_cpus());
+
+	irq = platform_get_irq(pmu_device, 0);
+	if (irq >= 0 && irq_is_percpu(irq)) {
+		on_each_cpu(cpu_pmu_disable_percpu_irq, &irq, 1);
+		free_percpu_irq(irq, &hw_events->percpu_pmu);
+	} else {
+		for (i = 0; i < irqs; ++i) {
+			int cpu = i;
+
+			if (cpu_pmu->irq_affinity)
+				cpu = cpu_pmu->irq_affinity[i];
+
+			if (!cpumask_test_and_clear_cpu(cpu, &cpu_pmu->active_irqs))
+				continue;
+			irq = platform_get_irq(pmu_device, i);
+			if (irq >= 0)
+				free_irq(irq, per_cpu_ptr(&hw_events->percpu_pmu, cpu));
+		}
+	}
+}
+
+static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
+{
+	int i, err, irq, irqs;
+	struct platform_device *pmu_device = cpu_pmu->plat_device;
+	struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;
+
+	if (!pmu_device)
+		return -ENODEV;
+
+	irqs = min(pmu_device->num_resources, num_possible_cpus());
+	if (irqs < 1) {
+		pr_warn_once("perf/ARM: No irqs for PMU defined, sampling events not supported\n");
+		return 0;
+	}
+
+	irq = platform_get_irq(pmu_device, 0);
+	if (irq >= 0 && irq_is_percpu(irq)) {
+		err = request_percpu_irq(irq, handler, "arm-pmu",
+					 &hw_events->percpu_pmu);
+		if (err) {
+			pr_err("unable to request IRQ%d for ARM PMU counters\n",
+				irq);
+			return err;
+		}
+		on_each_cpu(cpu_pmu_enable_percpu_irq, &irq, 1);
+	} else {
+		for (i = 0; i < irqs; ++i) {
+			int cpu = i;
+
+			err = 0;
+			irq = platform_get_irq(pmu_device, i);
+			if (irq < 0)
+				continue;
+
+			if (cpu_pmu->irq_affinity)
+				cpu = cpu_pmu->irq_affinity[i];
+
+			/*
+			 * 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)) && irqs > 1) {
+				pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",
+					irq, cpu);
+				continue;
+			}
+
+			err = request_irq(irq, handler,
+					  IRQF_NOBALANCING | IRQF_NO_THREAD, "arm-pmu",
+					  per_cpu_ptr(&hw_events->percpu_pmu, cpu));
+			if (err) {
+				pr_err("unable to request IRQ%d for ARM PMU counters\n",
+					irq);
+				return err;
+			}
+
+			cpumask_set_cpu(cpu, &cpu_pmu->active_irqs);
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * PMU hardware loses all context when a CPU goes offline.
+ * When a CPU is hotplugged back in, since some hardware registers are
+ * UNKNOWN at reset, the PMU must be explicitly reset to avoid reading
+ * junk values out of them.
+ */
+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
+		return NOTIFY_DONE;
+
+	return NOTIFY_OK;
+}
+
+static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
+{
+	int err;
+	int cpu;
+	struct pmu_hw_events __percpu *cpu_hw_events;
+
+	cpu_hw_events = alloc_percpu(struct pmu_hw_events);
+	if (!cpu_hw_events)
+		return -ENOMEM;
+
+	cpu_pmu->hotplug_nb.notifier_call = cpu_pmu_notify;
+	err = register_cpu_notifier(&cpu_pmu->hotplug_nb);
+	if (err)
+		goto out_hw_events;
+
+	for_each_possible_cpu(cpu) {
+		struct pmu_hw_events *events = per_cpu_ptr(cpu_hw_events, cpu);
+		raw_spin_lock_init(&events->pmu_lock);
+		events->percpu_pmu = cpu_pmu;
+	}
+
+	cpu_pmu->hw_events	= cpu_hw_events;
+	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);
+
+	/* If no interrupts available, set the corresponding capability flag */
+	if (!platform_get_irq(cpu_pmu->plat_device, 0))
+		cpu_pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
+
+	return 0;
+
+out_hw_events:
+	free_percpu(cpu_hw_events);
+	return err;
+}
+
+static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
+{
+	unregister_cpu_notifier(&cpu_pmu->hotplug_nb);
+	free_percpu(cpu_pmu->hw_events);
+}
+
+/*
+ * CPU PMU identification and probing.
+ */
+static int probe_current_pmu(struct arm_pmu *pmu,
+			     const struct pmu_probe_info *info)
+{
+	int cpu = get_cpu();
+	unsigned int cpuid = read_cpuid_id();
+	int ret = -ENODEV;
+
+	pr_info("probing PMU on CPU %d\n", cpu);
+
+	for (; info->init != NULL; info++) {
+		if ((cpuid & info->mask) != info->cpuid)
+			continue;
+		ret = info->init(pmu);
+		break;
+	}
+
+	put_cpu();
+	return ret;
+}
+
+static int of_pmu_irq_cfg(struct arm_pmu *pmu)
+{
+	int i, irq, *irqs;
+	struct platform_device *pdev = pmu->plat_device;
+
+	/* Don't bother with PPIs; they're already affine */
+	irq = platform_get_irq(pdev, 0);
+	if (irq >= 0 && irq_is_percpu(irq))
+		return 0;
+
+	irqs = kcalloc(pdev->num_resources, sizeof(*irqs), GFP_KERNEL);
+	if (!irqs)
+		return -ENOMEM;
+
+	for (i = 0; i < pdev->num_resources; ++i) {
+		struct device_node *dn;
+		int cpu;
+
+		dn = of_parse_phandle(pdev->dev.of_node, "interrupt-affinity",
+				      i);
+		if (!dn) {
+			pr_warn("Failed to parse %s/interrupt-affinity[%d]\n",
+				of_node_full_name(pdev->dev.of_node), i);
+			break;
+		}
+
+		for_each_possible_cpu(cpu)
+			if (arch_find_n_match_cpu_physical_id(dn, cpu, NULL))
+				break;
+
+		of_node_put(dn);
+		if (cpu >= nr_cpu_ids) {
+			pr_warn("Failed to find logical CPU for %s\n",
+				dn->name);
+			break;
+		}
+
+		irqs[i] = cpu;
+		cpumask_set_cpu(cpu, &pmu->supported_cpus);
+	}
+
+	if (i == pdev->num_resources) {
+		pmu->irq_affinity = irqs;
+	} else {
+		kfree(irqs);
+		cpumask_setall(&pmu->supported_cpus);
+	}
+
+	return 0;
+}
+
+int arm_pmu_device_probe(struct platform_device *pdev,
+			 const struct of_device_id *of_table,
+			 const struct pmu_probe_info *probe_table)
+{
+	const struct of_device_id *of_id;
+	const int (*init_fn)(struct arm_pmu *);
+	struct device_node *node = pdev->dev.of_node;
+	struct arm_pmu *pmu;
+	int ret = -ENODEV;
+
+	pmu = kzalloc(sizeof(struct arm_pmu), GFP_KERNEL);
+	if (!pmu) {
+		pr_info("failed to allocate PMU device!\n");
+		return -ENOMEM;
+	}
+
+	if (!__oprofile_cpu_pmu)
+		__oprofile_cpu_pmu = pmu;
+
+	pmu->plat_device = pdev;
+
+	if (node && (of_id = of_match_node(of_table, pdev->dev.of_node))) {
+		init_fn = of_id->data;
+
+		ret = of_pmu_irq_cfg(pmu);
+		if (!ret)
+			ret = init_fn(pmu);
+	} else {
+		ret = probe_current_pmu(pmu, probe_table);
+		cpumask_setall(&pmu->supported_cpus);
+	}
+
+	if (ret) {
+		pr_info("failed to probe PMU!\n");
+		goto out_free;
+	}
+
+	ret = cpu_pmu_init(pmu);
+	if (ret)
+		goto out_free;
+
+	ret = armpmu_register(pmu, -1);
+	if (ret)
+		goto out_destroy;
+
+	return 0;
+
+out_destroy:
+	cpu_pmu_destroy(pmu);
+out_free:
+	pr_info("failed to register PMU devices!\n");
+	kfree(pmu);
+	return ret;
+}

arch/arm/kernel/perf_event_cpu.c

···
-/*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright (C) 2012 ARM Limited
- *
- * Author: Will Deacon <[e-mail]>
- */
-#define pr_fmt(fmt) "CPU PMU: " fmt
-
-#include <linux/bitmap.h>
-#include <linux/export.h>
-#include <linux/kernel.h>
-#include <linux/of.h>
-#include <linux/platform_device.h>
-#include <linux/slab.h>
-#include <linux/spinlock.h>
-#include <linux/irq.h>
-#include <linux/irqdesc.h>
-
-#include <asm/cputype.h>
-#include <asm/irq_regs.h>
-#include <asm/pmu.h>
-
-/* Set at runtime when we know what CPU type we are. */
-static struct arm_pmu *cpu_pmu;
-
-/*
- * Despite the names, these two functions are CPU-specific and are used
- * by the OProfile/perf code.
- */
-const char *perf_pmu_name(void)
-{
-	if (!cpu_pmu)
-		return NULL;
-
-	return cpu_pmu->name;
-}
-EXPORT_SYMBOL_GPL(perf_pmu_name);
-
-int perf_num_counters(void)
-{
-	int max_events = 0;
-
-	if (cpu_pmu != NULL)
-		max_events = cpu_pmu->num_events;
-
-	return max_events;
-}
-EXPORT_SYMBOL_GPL(perf_num_counters);
-
-/* Include the PMU-specific implementations. */
-#include "perf_event_xscale.c"
-#include "perf_event_v6.c"
-#include "perf_event_v7.c"
-
-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)
-{
-	int i, irq, irqs;
-	struct platform_device *pmu_device = cpu_pmu->plat_device;
-	struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;
-
-	irqs = min(pmu_device->num_resources, num_possible_cpus());
-
-	irq = platform_get_irq(pmu_device, 0);
-	if (irq >= 0 && irq_is_percpu(irq)) {
-		on_each_cpu(cpu_pmu_disable_percpu_irq, &irq, 1);
-		free_percpu_irq(irq, &hw_events->percpu_pmu);
-	} else {
-		for (i = 0; i < irqs; ++i) {
-			int cpu = i;
-
-			if (cpu_pmu->irq_affinity)
-				cpu = cpu_pmu->irq_affinity[i];
-
-			if (!cpumask_test_and_clear_cpu(cpu, &cpu_pmu->active_irqs))
-				continue;
-			irq = platform_get_irq(pmu_device, i);
-			if (irq >= 0)
-				free_irq(irq, per_cpu_ptr(&hw_events->percpu_pmu, cpu));
-		}
-	}
-}
-
-static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
-{
-	int i, err, irq, irqs;
-	struct platform_device *pmu_device = cpu_pmu->plat_device;
-	struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;
-
-	if (!pmu_device)
-		return -ENODEV;
-
-	irqs = min(pmu_device->num_resources, num_possible_cpus());
-	if (irqs < 1) {
-		pr_warn_once("perf/ARM: No irqs for PMU defined, sampling events not supported\n");
-		return 0;
-	}
-
-	irq = platform_get_irq(pmu_device, 0);
-	if (irq >= 0 && irq_is_percpu(irq)) {
-		err = request_percpu_irq(irq, handler, "arm-pmu",
-					 &hw_events->percpu_pmu);
-		if (err) {
-			pr_err("unable to request IRQ%d for ARM PMU counters\n",
-				irq);
-			return err;
-		}
-		on_each_cpu(cpu_pmu_enable_percpu_irq, &irq, 1);
-	} else {
-		for (i = 0; i < irqs; ++i) {
-			int cpu = i;
-
-			err = 0;
-			irq = platform_get_irq(pmu_device, i);
-			if (irq < 0)
-				continue;
-
-			if (cpu_pmu->irq_affinity)
-				cpu = cpu_pmu->irq_affinity[i];
-
-			/*
-			 * 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)) && irqs > 1) {
-				pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",
-					irq, cpu);
-				continue;
-			}
-
-			err = request_irq(irq, handler,
-					  IRQF_NOBALANCING | IRQF_NO_THREAD, "arm-pmu",
-					  per_cpu_ptr(&hw_events->percpu_pmu, cpu));
-			if (err) {
-				pr_err("unable to request IRQ%d for ARM PMU counters\n",
-					irq);
-				return err;
-			}
-
-			cpumask_set_cpu(cpu, &cpu_pmu->active_irqs);
-		}
-	}
-
-	return 0;
-}
-
-/*
- * PMU hardware loses all context when a CPU goes offline.
- * When a CPU is hotplugged back in, since some hardware registers are
- * UNKNOWN at reset, the PMU must be explicitly reset to avoid reading
- * junk values out of them.
- */
-static int cpu_pmu_notify(struct notifier_block *b, unsigned long action,
-			  void *hcpu)
-{
-	struct arm_pmu *pmu = container_of(b, struct arm_pmu, hotplug_nb);
-
-	if ((action & ~CPU_TASKS_FROZEN) != CPU_STARTING)
-		return NOTIFY_DONE;
-
-	if (pmu->reset)
-		pmu->reset(pmu);
-	else
-		return NOTIFY_DONE;
-
-	return NOTIFY_OK;
-}
-
-static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
-{
-	int err;
-	int cpu;
-	struct pmu_hw_events __percpu *cpu_hw_events;
-
-	cpu_hw_events = alloc_percpu(struct pmu_hw_events);
-	if (!cpu_hw_events)
-		return -ENOMEM;
-
-	cpu_pmu->hotplug_nb.notifier_call = cpu_pmu_notify;
-	err = register_cpu_notifier(&cpu_pmu->hotplug_nb);
-	if (err)
-		goto out_hw_events;
-
-	for_each_possible_cpu(cpu) {
-		struct pmu_hw_events *events = per_cpu_ptr(cpu_hw_events, cpu);
-		raw_spin_lock_init(&events->pmu_lock);
-		events->percpu_pmu = cpu_pmu;
-	}
-
-	cpu_pmu->hw_events	= cpu_hw_events;
-	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(cpu_pmu->reset, cpu_pmu, 1);
-
-	/* If no interrupts available, set the corresponding capability flag */
-	if (!platform_get_irq(cpu_pmu->plat_device, 0))
-		cpu_pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
-
-	return 0;
-
-out_hw_events:
-	free_percpu(cpu_hw_events);
-	return err;
-}
-
-static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
-{
-	unregister_cpu_notifier(&cpu_pmu->hotplug_nb);
-	free_percpu(cpu_pmu->hw_events);
-}
-
-/*
- * PMU platform driver and devicetree bindings.
- */
-static const struct of_device_id cpu_pmu_of_device_ids[] = {
-	{.compatible = "arm,cortex-a17-pmu",	.data = armv7_a17_pmu_init},
-	{.compatible = "arm,cortex-a15-pmu",	.data = armv7_a15_pmu_init},
-	{.compatible = "arm,cortex-a12-pmu",	.data = armv7_a12_pmu_init},
-	{.compatible = "arm,cortex-a9-pmu",	.data = armv7_a9_pmu_init},
-	{.compatible = "arm,cortex-a8-pmu",	.data = armv7_a8_pmu_init},
-	{.compatible = "arm,cortex-a7-pmu",	.data = armv7_a7_pmu_init},
-	{.compatible = "arm,cortex-a5-pmu",	.data = armv7_a5_pmu_init},
-	{.compatible = "arm,arm11mpcore-pmu",	.data = armv6mpcore_pmu_init},
-	{.compatible = "arm,arm1176-pmu",	.data = armv6_1176_pmu_init},
-	{.compatible = "arm,arm1136-pmu",	.data = armv6_1136_pmu_init},
-	{.compatible = "qcom,krait-pmu",	.data = krait_pmu_init},
-	{.compatible = "qcom,scorpion-pmu",	.data = scorpion_pmu_init},
-	{.compatible = "qcom,scorpion-mp-pmu",	.data = scorpion_mp_pmu_init},
-	{},
-};
-
-static struct platform_device_id cpu_pmu_plat_device_ids[] = {
-	{.name = "arm-pmu"},
-	{.name = "armv6-pmu"},
-	{.name = "armv7-pmu"},
-	{.name = "xscale-pmu"},
-	{},
-};
-
-static const struct pmu_probe_info pmu_probe_table[] = {
-	ARM_PMU_PROBE(ARM_CPU_PART_ARM1136, armv6_1136_pmu_init),
-	ARM_PMU_PROBE(ARM_CPU_PART_ARM1156, armv6_1156_pmu_init),
-	ARM_PMU_PROBE(ARM_CPU_PART_ARM1176, armv6_1176_pmu_init),
-	ARM_PMU_PROBE(ARM_CPU_PART_ARM11MPCORE, armv6mpcore_pmu_init),
-	ARM_PMU_PROBE(ARM_CPU_PART_CORTEX_A8, armv7_a8_pmu_init),
-	ARM_PMU_PROBE(ARM_CPU_PART_CORTEX_A9, armv7_a9_pmu_init),
-	XSCALE_PMU_PROBE(ARM_CPU_XSCALE_ARCH_V1, xscale1pmu_init),
-	XSCALE_PMU_PROBE(ARM_CPU_XSCALE_ARCH_V2, xscale2pmu_init),
-	{ /* sentinel value */ }
-};
-
-/*
- * CPU PMU identification and probing.
- */
-static int probe_current_pmu(struct arm_pmu *pmu)
-{
-	int cpu = get_cpu();
-	unsigned int cpuid = read_cpuid_id();
-	int ret = -ENODEV;
-	const struct pmu_probe_info *info;
-
-	pr_info("probing PMU on CPU %d\n", cpu);
-
-	for (info = pmu_probe_table; info->init != NULL; info++) {
-		if ((cpuid & info->mask) != info->cpuid)
-			continue;
-		ret = info->init(pmu);
-		break;
-	}
-
-	put_cpu();
-	return ret;
-}
-
-static int of_pmu_irq_cfg(struct platform_device *pdev)
-{
-	int i;
-	int *irqs = kcalloc(pdev->num_resources, sizeof(*irqs), GFP_KERNEL);
-
-	if (!irqs)
-		return -ENOMEM;
-
-	for (i = 0; i < pdev->num_resources; ++i) {
-		struct device_node *dn;
-		int cpu;
-
-		dn = of_parse_phandle(pdev->dev.of_node, "interrupt-affinity",
-				      i);
-		if (!dn) {
-			pr_warn("Failed to parse %s/interrupt-affinity[%d]\n",
-				of_node_full_name(dn), i);
-			break;
-		}
-
-		for_each_possible_cpu(cpu)
-			if (arch_find_n_match_cpu_physical_id(dn, cpu, NULL))
-				break;
-
-		of_node_put(dn);
-		if (cpu >= nr_cpu_ids) {
-			pr_warn("Failed to find logical CPU for %s\n",
-				dn->name);
-			break;
-		}
-
-		irqs[i] = cpu;
-	}
-
-	if (i == pdev->num_resources)
-		cpu_pmu->irq_affinity = irqs;
-	else
-		kfree(irqs);
-
-	return 0;
-}
-
-static int cpu_pmu_device_probe(struct platform_device *pdev)
-{
-	const struct of_device_id *of_id;
-	const int (*init_fn)(struct arm_pmu *);
-	struct device_node *node = pdev->dev.of_node;
-	struct arm_pmu *pmu;
-	int ret = -ENODEV;
-
-	if (cpu_pmu) {
-		pr_info("attempt to register multiple PMU devices!\n");
-		return -ENOSPC;
-	}
-
-	pmu = kzalloc(sizeof(struct arm_pmu), GFP_KERNEL);
-	if (!pmu) {
-		pr_info("failed to allocate PMU device!\n");
-		return -ENOMEM;
-	}
-
-	cpu_pmu = pmu;
-	cpu_pmu->plat_device = pdev;
-
-	if (node && (of_id = of_match_node(cpu_pmu_of_device_ids, pdev->dev.of_node))) {
-		init_fn = of_id->data;
-
-		ret = of_pmu_irq_cfg(pdev);
-		if (!ret)
-			ret = init_fn(pmu);
-	} else {
-		ret = probe_current_pmu(pmu);
-	}
-
-	if (ret) {
-		pr_info("failed to probe PMU!\n");
-		goto out_free;
-	}
-
-	ret = cpu_pmu_init(cpu_pmu);
-	if (ret)
-		goto out_free;
-
-	ret = armpmu_register(cpu_pmu, -1);
-	if (ret)
-		goto out_destroy;
-
-	return 0;
-
-out_destroy:
-	cpu_pmu_destroy(cpu_pmu);
-out_free:
-	pr_info("failed to register PMU devices!\n");
-	kfree(pmu);
-	return ret;
-}
-
-static struct platform_driver cpu_pmu_driver = {
-	.driver		= {
-		.name	= "arm-pmu",
-		.pm	= &armpmu_dev_pm_ops,
-		.of_match_table = cpu_pmu_of_device_ids,
-	},
-	.probe		= cpu_pmu_device_probe,
-	.id_table	= cpu_pmu_plat_device_ids,
-};
-
-static int __init register_pmu_driver(void)
-{
-	return platform_driver_register(&cpu_pmu_driver);
-}
-device_initcall(register_pmu_driver);

arch/arm/kernel/perf_event_v6.c

···
  */
 
 #if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_V6K)
+
+#include <asm/cputype.h>
+#include <asm/irq_regs.h>
+#include <asm/pmu.h>
+
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
 enum armv6_perf_types {
 	ARMV6_PERFCTR_ICACHE_MISS	    = 0x0,
 	ARMV6_PERFCTR_IBUF_STALL	    = 0x1,
···
 
 	return 0;
 }
-#else
-static int armv6_1136_pmu_init(struct arm_pmu *cpu_pmu)
+
+static struct of_device_id armv6_pmu_of_device_ids[] = {
+	{.compatible = "arm,arm11mpcore-pmu",	.data = armv6mpcore_pmu_init},
+	{.compatible = "arm,arm1176-pmu",	.data = armv6_1176_pmu_init},
+	{.compatible = "arm,arm1136-pmu",	.data = armv6_1136_pmu_init},
+	{ /* sentinel value */ }
+};
+
+static const struct pmu_probe_info armv6_pmu_probe_table[] = {
+	ARM_PMU_PROBE(ARM_CPU_PART_ARM1136, armv6_1136_pmu_init),
+	ARM_PMU_PROBE(ARM_CPU_PART_ARM1156, armv6_1156_pmu_init),
+	ARM_PMU_PROBE(ARM_CPU_PART_ARM1176, armv6_1176_pmu_init),
+	ARM_PMU_PROBE(ARM_CPU_PART_ARM11MPCORE, armv6mpcore_pmu_init),
+	{ /* sentinel value */ }
+};
+
+static int armv6_pmu_device_probe(struct platform_device *pdev)
 {
-	return -ENODEV;
+	return arm_pmu_device_probe(pdev, armv6_pmu_of_device_ids,
+				    armv6_pmu_probe_table);
 }
 
-static int armv6_1156_pmu_init(struct arm_pmu *cpu_pmu)
-{
-	return -ENODEV;
-}
+static struct platform_driver armv6_pmu_driver = {
+	.driver		= {
+		.name	= "armv6-pmu",
+		.of_match_table = armv6_pmu_of_device_ids,
+	},
+	.probe		= armv6_pmu_device_probe,
+};
 
-static int armv6_1176_pmu_init(struct arm_pmu *cpu_pmu)
+static int __init register_armv6_pmu_driver(void)
 {
-	return -ENODEV;
+	return platform_driver_register(&armv6_pmu_driver);
 }
-
-static int armv6mpcore_pmu_init(struct arm_pmu *cpu_pmu)
-{
-	return -ENODEV;
-}
+device_initcall(register_armv6_pmu_driver);
 #endif	/* CONFIG_CPU_V6 || CONFIG_CPU_V6K */

arch/arm/kernel/perf_event_v7.c

···
 #ifdef CONFIG_CPU_V7
 
 #include <asm/cp15.h>
+#include <asm/cputype.h>
+#include <asm/irq_regs.h>
+#include <asm/pmu.h>
 #include <asm/vfp.h>
 #include "../vfp/vfpinstr.h"
+
+#include <linux/of.h>
+#include <linux/platform_device.h>
 
 /*
  * Common ARMv7 event types
···
 	cpu_pmu->max_period	= (1LLU << 32) - 1;
 };
 
-static u32 armv7_read_num_pmnc_events(void)
+static void armv7_read_num_pmnc_events(void *info)
 {
-	u32 nb_cnt;
+	int *nb_cnt = info;
 
 	/* Read the nb of CNTx counters supported from PMNC */
-	nb_cnt = (armv7_pmnc_read() >> ARMV7_PMNC_N_SHIFT) & ARMV7_PMNC_N_MASK;
+	*nb_cnt = (armv7_pmnc_read() >> ARMV7_PMNC_N_SHIFT) & ARMV7_PMNC_N_MASK;
 
-	/* Add the CPU cycles counter and return */
-	return nb_cnt + 1;
+	/* Add the CPU cycles counter */
+	*nb_cnt += 1;
+}
+
+static int armv7_probe_num_events(struct arm_pmu *arm_pmu)
+{
+	return smp_call_function_any(&arm_pmu->supported_cpus,
+				     armv7_read_num_pmnc_events,
+				     &arm_pmu->num_events, 1);
 }
 
 static int armv7_a8_pmu_init(struct arm_pmu *cpu_pmu)
···
 	armv7pmu_init(cpu_pmu);
 	cpu_pmu->name		= "armv7_cortex_a8";
 	cpu_pmu->map_event	= armv7_a8_map_event;
-	cpu_pmu->num_events	= armv7_read_num_pmnc_events();
-	return 0;
+	return armv7_probe_num_events(cpu_pmu);
 }
 
 static int armv7_a9_pmu_init(struct arm_pmu *cpu_pmu)
···
 	armv7pmu_init(cpu_pmu);
 	cpu_pmu->name		= "armv7_cortex_a9";
 	cpu_pmu->map_event	= armv7_a9_map_event;
-	cpu_pmu->num_events	= armv7_read_num_pmnc_events();
-	return 0;
+	return armv7_probe_num_events(cpu_pmu);
 }
 
 static int armv7_a5_pmu_init(struct arm_pmu *cpu_pmu)
···
 	armv7pmu_init(cpu_pmu);
 	cpu_pmu->name		= "armv7_cortex_a5";
 	cpu_pmu->map_event	= armv7_a5_map_event;
-	cpu_pmu->num_events	= armv7_read_num_pmnc_events();
-	return 0;
+	return armv7_probe_num_events(cpu_pmu);
 }
 
 static int armv7_a15_pmu_init(struct arm_pmu *cpu_pmu)
···
 	armv7pmu_init(cpu_pmu);
 	cpu_pmu->name		= "armv7_cortex_a15";
 	cpu_pmu->map_event	= armv7_a15_map_event;
-	cpu_pmu->num_events	= armv7_read_num_pmnc_events();
 	cpu_pmu->set_event_filter = armv7pmu_set_event_filter;
-	return 0;
+	return armv7_probe_num_events(cpu_pmu);
 }
 
 static int armv7_a7_pmu_init(struct arm_pmu *cpu_pmu)
···
 	armv7pmu_init(cpu_pmu);
 	cpu_pmu->name		= "armv7_cortex_a7";
 	cpu_pmu->map_event	= armv7_a7_map_event;
-	cpu_pmu->num_events	= armv7_read_num_pmnc_events();
 	cpu_pmu->set_event_filter = armv7pmu_set_event_filter;
-	return 0;
+	return armv7_probe_num_events(cpu_pmu);
 }
 
 static int armv7_a12_pmu_init(struct arm_pmu *cpu_pmu)
···
 	armv7pmu_init(cpu_pmu);
 	cpu_pmu->name		= "armv7_cortex_a12";
 	cpu_pmu->map_event	= armv7_a12_map_event;
-	cpu_pmu->num_events	= armv7_read_num_pmnc_events();
 	cpu_pmu->set_event_filter = armv7pmu_set_event_filter;
-	return 0;
+	return armv7_probe_num_events(cpu_pmu);
 }
 
 static int armv7_a17_pmu_init(struct arm_pmu *cpu_pmu)
 {
-	armv7_a12_pmu_init(cpu_pmu);
+	int ret = armv7_a12_pmu_init(cpu_pmu);
 	cpu_pmu->name = "armv7_cortex_a17";
-	return 0;
+	return ret;
 }
 
 /*
···
 		cpu_pmu->map_event = krait_map_event_no_branch;
 	else
 		cpu_pmu->map_event = krait_map_event;
-	cpu_pmu->num_events	= armv7_read_num_pmnc_events();
 	cpu_pmu->set_event_filter = armv7pmu_set_event_filter;
 	cpu_pmu->reset		= krait_pmu_reset;
 	cpu_pmu->enable		= krait_pmu_enable_event;
 	cpu_pmu->disable	= krait_pmu_disable_event;
 	cpu_pmu->get_event_idx	= krait_pmu_get_event_idx;
 	cpu_pmu->clear_event_idx = krait_pmu_clear_event_idx;
-	return 0;
+	return armv7_probe_num_events(cpu_pmu);
 }
 
 /*
···
 	armv7pmu_init(cpu_pmu);
 	cpu_pmu->name		= "armv7_scorpion";
 	cpu_pmu->map_event	= scorpion_map_event;
-	cpu_pmu->num_events	= armv7_read_num_pmnc_events();
 	cpu_pmu->reset		= scorpion_pmu_reset;
 	cpu_pmu->enable		= scorpion_pmu_enable_event;
 	cpu_pmu->disable	= scorpion_pmu_disable_event;
 	cpu_pmu->get_event_idx	= scorpion_pmu_get_event_idx;
 	cpu_pmu->clear_event_idx = scorpion_pmu_clear_event_idx;
-	return 0;
+	return armv7_probe_num_events(cpu_pmu);
 }
 
 static int scorpion_mp_pmu_init(struct arm_pmu *cpu_pmu)
···
 	armv7pmu_init(cpu_pmu);
 	cpu_pmu->name		= "armv7_scorpion_mp";
 	cpu_pmu->map_event	= scorpion_map_event;
-	cpu_pmu->num_events	= armv7_read_num_pmnc_events();
 	cpu_pmu->reset		= scorpion_pmu_reset;
 	cpu_pmu->enable		= scorpion_pmu_enable_event;
 	cpu_pmu->disable	= scorpion_pmu_disable_event;
 	cpu_pmu->get_event_idx	= scorpion_pmu_get_event_idx;
 	cpu_pmu->clear_event_idx = scorpion_pmu_clear_event_idx;
-	return 0;
-}
-#else
-static inline int armv7_a8_pmu_init(struct arm_pmu *cpu_pmu)
-{
-	return -ENODEV;
+	return armv7_probe_num_events(cpu_pmu);
 }
 
-static inline int armv7_a9_pmu_init(struct arm_pmu *cpu_pmu)
+static const struct of_device_id armv7_pmu_of_device_ids[] = {
+	{.compatible = "arm,cortex-a17-pmu",	.data = armv7_a17_pmu_init},
+	{.compatible = "arm,cortex-a15-pmu",	.data = armv7_a15_pmu_init},
+	{.compatible = "arm,cortex-a12-pmu",	.data = armv7_a12_pmu_init},
+	{.compatible = "arm,cortex-a9-pmu",	.data = armv7_a9_pmu_init},
+	{.compatible = "arm,cortex-a8-pmu",	.data = armv7_a8_pmu_init},
+	{.compatible = "arm,cortex-a7-pmu",	.data = armv7_a7_pmu_init},
+	{.compatible = "arm,cortex-a5-pmu",	.data = armv7_a5_pmu_init},
+	{.compatible = "qcom,krait-pmu",	.data = krait_pmu_init},
+	{.compatible = "qcom,scorpion-pmu",	.data = scorpion_pmu_init},
+	{.compatible = "qcom,scorpion-mp-pmu",	.data = scorpion_mp_pmu_init},
+	{},
+};
+
+static const struct pmu_probe_info armv7_pmu_probe_table[] = {
+	ARM_PMU_PROBE(ARM_CPU_PART_CORTEX_A8, armv7_a8_pmu_init),
+	ARM_PMU_PROBE(ARM_CPU_PART_CORTEX_A9, armv7_a9_pmu_init),
+	{ /* sentinel value */ }
+};
+
+
+static int armv7_pmu_device_probe(struct platform_device *pdev)
 {
-	return -ENODEV;
+	return arm_pmu_device_probe(pdev, armv7_pmu_of_device_ids,
+				    armv7_pmu_probe_table);
 }
 
-static inline int armv7_a5_pmu_init(struct arm_pmu *cpu_pmu)
-{
-	return -ENODEV;
-}
+static struct platform_driver armv7_pmu_driver = {
+	.driver		= {
+		.name	= "armv7-pmu",
+		.of_match_table = armv7_pmu_of_device_ids,
+	},
+	.probe		= armv7_pmu_device_probe,
+};
 
-static inline int armv7_a15_pmu_init(struct arm_pmu *cpu_pmu)
+static int __init register_armv7_pmu_driver(void)
 {
-	return -ENODEV;
+	return platform_driver_register(&armv7_pmu_driver);
 }
-
-static inline int armv7_a7_pmu_init(struct arm_pmu *cpu_pmu)
-{
-	return -ENODEV;
-}
-
-static inline int armv7_a12_pmu_init(struct arm_pmu *cpu_pmu)
-{
-	return -ENODEV;
-}
-
-static inline int armv7_a17_pmu_init(struct arm_pmu *cpu_pmu)
-{
-	return -ENODEV;
-}
-
-static inline int krait_pmu_init(struct arm_pmu *cpu_pmu)
-{
-	return -ENODEV;
-}
-
-static inline int scorpion_pmu_init(struct arm_pmu *cpu_pmu)
-{
-	return -ENODEV;
-}
-
-static inline int scorpion_mp_pmu_init(struct arm_pmu *cpu_pmu)
-{
-	return -ENODEV;
-}
+device_initcall(register_armv7_pmu_driver);
 #endif	/* CONFIG_CPU_V7 */

arch/arm/kernel/perf_event_xscale.c

···
  */
 
 #ifdef CONFIG_CPU_XSCALE
+
+#include <asm/cputype.h>
+#include <asm/irq_regs.h>
+#include <asm/pmu.h>
+
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
 enum xscale_perf_types {
 	XSCALE_PERFCTR_ICACHE_MISS		= 0x00,
 	XSCALE_PERFCTR_ICACHE_NO_DELIVER	= 0x01,
···
 
 	return 0;
 }
-#else
-static inline int xscale1pmu_init(struct arm_pmu *cpu_pmu)
+
+static const struct pmu_probe_info xscale_pmu_probe_table[] = {
+	XSCALE_PMU_PROBE(ARM_CPU_XSCALE_ARCH_V1, xscale1pmu_init),
+	XSCALE_PMU_PROBE(ARM_CPU_XSCALE_ARCH_V2, xscale2pmu_init),
+	{ /* sentinel value */ }
+};
+
+static int xscale_pmu_device_probe(struct platform_device *pdev)
 {
-	return -ENODEV;
+	return arm_pmu_device_probe(pdev, NULL, xscale_pmu_probe_table);
 }
 
-static inline int xscale2pmu_init(struct arm_pmu *cpu_pmu)
+static struct platform_driver xscale_pmu_driver = {
+	.driver		= {
+		.name	= "xscale-pmu",
+	},
+	.probe		= xscale_pmu_device_probe,
+};
+
+static int __init register_xscale_pmu_driver(void)
 {
-	return -ENODEV;
+	return platform_driver_register(&xscale_pmu_driver);
 }
+device_initcall(register_xscale_pmu_driver);
 #endif	/* CONFIG_CPU_XSCALE */

include/linux/perf_event.h

···
 	 * Free pmu-private AUX data structures
 	 */
 	void (*free_aux)		(void *aux); /* optional */
+
+	/*
+	 * Filter events for PMU-specific reasons.
+	 */
+	int (*filter_match)		(struct perf_event *event); /* optional */
 };
 
 /**

kernel/events/core.c

···
 
 core_initcall(perf_workqueue_init);
 
+static inline int pmu_filter_match(struct perf_event *event)
+{
+	struct pmu *pmu = event->pmu;
+	return pmu->filter_match ? pmu->filter_match(event) : 1;
+}
+
 static inline int
 event_filter_match(struct perf_event *event)
 {
 	return (event->cpu == -1 || event->cpu == smp_processor_id())
-	    && perf_cgroup_match(event);
+	    && perf_cgroup_match(event) && pmu_filter_match(event);
 }
 
 static void