summaryrefslogtreecommitdiff
path: root/arch/arm/kernel/perf_event.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/kernel/perf_event.c')
-rw-r--r--arch/arm/kernel/perf_event.c408
1 files changed, 375 insertions, 33 deletions
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index 4a86a0133ac3..357f57ea83f4 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -11,12 +11,18 @@
*/
#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>
@@ -229,6 +235,10 @@ 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. */
@@ -344,20 +354,12 @@ static void
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;
@@ -454,6 +456,17 @@ 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 +502,10 @@ 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);
}
@@ -496,34 +513,25 @@ static void armpmu_enable(struct pmu *pmu)
static void armpmu_disable(struct pmu *pmu)
{
struct arm_pmu *armpmu = to_arm_pmu(pmu);
- armpmu->stop(armpmu);
-}
-
-#ifdef CONFIG_PM
-static int armpmu_runtime_resume(struct device *dev)
-{
- struct arm_pmu_platdata *plat = dev_get_platdata(dev);
- if (plat && plat->runtime_resume)
- return plat->runtime_resume(dev);
+ /* For task-bound events we may be called on other CPUs */
+ if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
+ return;
- return 0;
+ armpmu->stop(armpmu);
}
-static int armpmu_runtime_suspend(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_suspend)
- return plat->runtime_suspend(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);
}
-#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)
{
@@ -539,15 +547,349 @@ 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;
+}