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-rw-r--r--arch/arm/kernel/perf_event.c553
1 files changed, 553 insertions, 0 deletions
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
new file mode 100644
index 000000000..4a86a0133
--- /dev/null
+++ b/arch/arm/kernel/perf_event.c
@@ -0,0 +1,553 @@
+#undef DEBUG
+
+/*
+ * ARM performance counter support.
+ *
+ * Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
+ * Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com>
+ *
+ * This code is based on the sparc64 perf event code, which is in turn based
+ * on the x86 code.
+ */
+#define pr_fmt(fmt) "hw perfevents: " fmt
+
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/irq.h>
+#include <linux/irqdesc.h>
+
+#include <asm/irq_regs.h>
+#include <asm/pmu.h>
+
+static int
+armpmu_map_cache_event(const unsigned (*cache_map)
+ [PERF_COUNT_HW_CACHE_MAX]
+ [PERF_COUNT_HW_CACHE_OP_MAX]
+ [PERF_COUNT_HW_CACHE_RESULT_MAX],
+ u64 config)
+{
+ unsigned int cache_type, cache_op, cache_result, ret;
+
+ cache_type = (config >> 0) & 0xff;
+ if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
+ return -EINVAL;
+
+ cache_op = (config >> 8) & 0xff;
+ if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
+ return -EINVAL;
+
+ cache_result = (config >> 16) & 0xff;
+ if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
+ return -EINVAL;
+
+ ret = (int)(*cache_map)[cache_type][cache_op][cache_result];
+
+ if (ret == CACHE_OP_UNSUPPORTED)
+ return -ENOENT;
+
+ return ret;
+}
+
+static int
+armpmu_map_hw_event(const unsigned (*event_map)[PERF_COUNT_HW_MAX], u64 config)
+{
+ int mapping;
+
+ if (config >= PERF_COUNT_HW_MAX)
+ return -EINVAL;
+
+ mapping = (*event_map)[config];
+ return mapping == HW_OP_UNSUPPORTED ? -ENOENT : mapping;
+}
+
+static int
+armpmu_map_raw_event(u32 raw_event_mask, u64 config)
+{
+ return (int)(config & raw_event_mask);
+}
+
+int
+armpmu_map_event(struct perf_event *event,
+ const unsigned (*event_map)[PERF_COUNT_HW_MAX],
+ const unsigned (*cache_map)
+ [PERF_COUNT_HW_CACHE_MAX]
+ [PERF_COUNT_HW_CACHE_OP_MAX]
+ [PERF_COUNT_HW_CACHE_RESULT_MAX],
+ u32 raw_event_mask)
+{
+ u64 config = event->attr.config;
+ int type = event->attr.type;
+
+ if (type == event->pmu->type)
+ return armpmu_map_raw_event(raw_event_mask, config);
+
+ switch (type) {
+ case PERF_TYPE_HARDWARE:
+ return armpmu_map_hw_event(event_map, config);
+ case PERF_TYPE_HW_CACHE:
+ return armpmu_map_cache_event(cache_map, config);
+ case PERF_TYPE_RAW:
+ return armpmu_map_raw_event(raw_event_mask, config);
+ }
+
+ return -ENOENT;
+}
+
+int armpmu_event_set_period(struct perf_event *event)
+{
+ struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
+ struct hw_perf_event *hwc = &event->hw;
+ s64 left = local64_read(&hwc->period_left);
+ s64 period = hwc->sample_period;
+ int ret = 0;
+
+ if (unlikely(left <= -period)) {
+ left = period;
+ local64_set(&hwc->period_left, left);
+ hwc->last_period = period;
+ ret = 1;
+ }
+
+ if (unlikely(left <= 0)) {
+ left += period;
+ local64_set(&hwc->period_left, left);
+ hwc->last_period = period;
+ ret = 1;
+ }
+
+ /*
+ * Limit the maximum period to prevent the counter value
+ * from overtaking the one we are about to program. In
+ * effect we are reducing max_period to account for
+ * interrupt latency (and we are being very conservative).
+ */
+ if (left > (armpmu->max_period >> 1))
+ left = armpmu->max_period >> 1;
+
+ local64_set(&hwc->prev_count, (u64)-left);
+
+ armpmu->write_counter(event, (u64)(-left) & 0xffffffff);
+
+ perf_event_update_userpage(event);
+
+ return ret;
+}
+
+u64 armpmu_event_update(struct perf_event *event)
+{
+ struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
+ struct hw_perf_event *hwc = &event->hw;
+ u64 delta, prev_raw_count, new_raw_count;
+
+again:
+ prev_raw_count = local64_read(&hwc->prev_count);
+ new_raw_count = armpmu->read_counter(event);
+
+ if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
+ new_raw_count) != prev_raw_count)
+ goto again;
+
+ delta = (new_raw_count - prev_raw_count) & armpmu->max_period;
+
+ local64_add(delta, &event->count);
+ local64_sub(delta, &hwc->period_left);
+
+ return new_raw_count;
+}
+
+static void
+armpmu_read(struct perf_event *event)
+{
+ armpmu_event_update(event);
+}
+
+static void
+armpmu_stop(struct perf_event *event, int flags)
+{
+ struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
+ struct hw_perf_event *hwc = &event->hw;
+
+ /*
+ * ARM pmu always has to update the counter, so ignore
+ * PERF_EF_UPDATE, see comments in armpmu_start().
+ */
+ if (!(hwc->state & PERF_HES_STOPPED)) {
+ armpmu->disable(event);
+ armpmu_event_update(event);
+ hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
+ }
+}
+
+static void armpmu_start(struct perf_event *event, int flags)
+{
+ struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
+ struct hw_perf_event *hwc = &event->hw;
+
+ /*
+ * ARM pmu always has to reprogram the period, so ignore
+ * PERF_EF_RELOAD, see the comment below.
+ */
+ if (flags & PERF_EF_RELOAD)
+ WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
+
+ hwc->state = 0;
+ /*
+ * Set the period again. Some counters can't be stopped, so when we
+ * were stopped we simply disabled the IRQ source and the counter
+ * may have been left counting. If we don't do this step then we may
+ * get an interrupt too soon or *way* too late if the overflow has
+ * happened since disabling.
+ */
+ armpmu_event_set_period(event);
+ armpmu->enable(event);
+}
+
+static void
+armpmu_del(struct perf_event *event, int flags)
+{
+ struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
+ struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
+ struct hw_perf_event *hwc = &event->hw;
+ int idx = hwc->idx;
+
+ armpmu_stop(event, PERF_EF_UPDATE);
+ hw_events->events[idx] = NULL;
+ clear_bit(idx, hw_events->used_mask);
+ if (armpmu->clear_event_idx)
+ armpmu->clear_event_idx(hw_events, event);
+
+ perf_event_update_userpage(event);
+}
+
+static int
+armpmu_add(struct perf_event *event, int flags)
+{
+ struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
+ struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
+ struct hw_perf_event *hwc = &event->hw;
+ int idx;
+ int err = 0;
+
+ perf_pmu_disable(event->pmu);
+
+ /* If we don't have a space for the counter then finish early. */
+ idx = armpmu->get_event_idx(hw_events, event);
+ if (idx < 0) {
+ err = idx;
+ goto out;
+ }
+
+ /*
+ * If there is an event in the counter we are going to use then make
+ * sure it is disabled.
+ */
+ event->hw.idx = idx;
+ armpmu->disable(event);
+ hw_events->events[idx] = event;
+
+ hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
+ if (flags & PERF_EF_START)
+ armpmu_start(event, PERF_EF_RELOAD);
+
+ /* Propagate our changes to the userspace mapping. */
+ perf_event_update_userpage(event);
+
+out:
+ perf_pmu_enable(event->pmu);
+ return err;
+}
+
+static int
+validate_event(struct pmu *pmu, struct pmu_hw_events *hw_events,
+ struct perf_event *event)
+{
+ struct arm_pmu *armpmu;
+
+ if (is_software_event(event))
+ return 1;
+
+ /*
+ * Reject groups spanning multiple HW PMUs (e.g. CPU + CCI). The
+ * core perf code won't check that the pmu->ctx == leader->ctx
+ * until after pmu->event_init(event).
+ */
+ if (event->pmu != pmu)
+ return 0;
+
+ if (event->state < PERF_EVENT_STATE_OFF)
+ return 1;
+
+ if (event->state == PERF_EVENT_STATE_OFF && !event->attr.enable_on_exec)
+ return 1;
+
+ armpmu = to_arm_pmu(event->pmu);
+ return armpmu->get_event_idx(hw_events, event) >= 0;
+}
+
+static int
+validate_group(struct perf_event *event)
+{
+ struct perf_event *sibling, *leader = event->group_leader;
+ struct pmu_hw_events fake_pmu;
+
+ /*
+ * Initialise the fake PMU. We only need to populate the
+ * used_mask for the purposes of validation.
+ */
+ memset(&fake_pmu.used_mask, 0, sizeof(fake_pmu.used_mask));
+
+ if (!validate_event(event->pmu, &fake_pmu, leader))
+ return -EINVAL;
+
+ list_for_each_entry(sibling, &leader->sibling_list, group_entry) {
+ if (!validate_event(event->pmu, &fake_pmu, sibling))
+ return -EINVAL;
+ }
+
+ if (!validate_event(event->pmu, &fake_pmu, event))
+ return -EINVAL;
+
+ return 0;
+}
+
+static irqreturn_t armpmu_dispatch_irq(int irq, void *dev)
+{
+ struct arm_pmu *armpmu;
+ struct platform_device *plat_device;
+ struct arm_pmu_platdata *plat;
+ int ret;
+ u64 start_clock, finish_clock;
+
+ /*
+ * we request the IRQ with a (possibly percpu) struct arm_pmu**, but
+ * the handlers expect a struct arm_pmu*. The percpu_irq framework will
+ * do any necessary shifting, we just need to perform the first
+ * dereference.
+ */
+ armpmu = *(void **)dev;
+ plat_device = armpmu->plat_device;
+ plat = dev_get_platdata(&plat_device->dev);
+
+ start_clock = sched_clock();
+ if (plat && plat->handle_irq)
+ ret = plat->handle_irq(irq, armpmu, armpmu->handle_irq);
+ else
+ ret = armpmu->handle_irq(irq, armpmu);
+ finish_clock = sched_clock();
+
+ perf_sample_event_took(finish_clock - start_clock);
+ return ret;
+}
+
+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);
+ 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)
+{
+ return attr->exclude_idle || attr->exclude_user ||
+ attr->exclude_kernel || attr->exclude_hv;
+}
+
+static int
+__hw_perf_event_init(struct perf_event *event)
+{
+ struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
+ struct hw_perf_event *hwc = &event->hw;
+ int mapping;
+
+ mapping = armpmu->map_event(event);
+
+ if (mapping < 0) {
+ pr_debug("event %x:%llx not supported\n", event->attr.type,
+ event->attr.config);
+ return mapping;
+ }
+
+ /*
+ * We don't assign an index until we actually place the event onto
+ * hardware. Use -1 to signify that we haven't decided where to put it
+ * yet. For SMP systems, each core has it's own PMU so we can't do any
+ * clever allocation or constraints checking at this point.
+ */
+ hwc->idx = -1;
+ hwc->config_base = 0;
+ hwc->config = 0;
+ hwc->event_base = 0;
+
+ /*
+ * Check whether we need to exclude the counter from certain modes.
+ */
+ if ((!armpmu->set_event_filter ||
+ armpmu->set_event_filter(hwc, &event->attr)) &&
+ event_requires_mode_exclusion(&event->attr)) {
+ pr_debug("ARM performance counters do not support "
+ "mode exclusion\n");
+ return -EOPNOTSUPP;
+ }
+
+ /*
+ * Store the event encoding into the config_base field.
+ */
+ hwc->config_base |= (unsigned long)mapping;
+
+ if (!is_sampling_event(event)) {
+ /*
+ * For non-sampling runs, limit the sample_period to half
+ * of the counter width. That way, the new counter value
+ * is far less likely to overtake the previous one unless
+ * you have some serious IRQ latency issues.
+ */
+ hwc->sample_period = armpmu->max_period >> 1;
+ hwc->last_period = hwc->sample_period;
+ local64_set(&hwc->period_left, hwc->sample_period);
+ }
+
+ if (event->group_leader != event) {
+ if (validate_group(event) != 0)
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+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;
+
+ /* does not support taken branch sampling */
+ if (has_branch_stack(event))
+ return -EOPNOTSUPP;
+
+ 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;
+}
+
+static void armpmu_enable(struct pmu *pmu)
+{
+ struct arm_pmu *armpmu = to_arm_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);
+
+ if (enabled)
+ armpmu->start(armpmu);
+}
+
+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);
+
+ return 0;
+}
+
+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)
+{
+ atomic_set(&armpmu->active_events, 0);
+ mutex_init(&armpmu->reserve_mutex);
+
+ armpmu->pmu = (struct pmu) {
+ .pmu_enable = armpmu_enable,
+ .pmu_disable = armpmu_disable,
+ .event_init = armpmu_event_init,
+ .add = armpmu_add,
+ .del = armpmu_del,
+ .start = armpmu_start,
+ .stop = armpmu_stop,
+ .read = armpmu_read,
+ };
+}
+
+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);
+}
+