1 files changed, 775 insertions, 0 deletions

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
new file mode 100644
index 00000000..2b5b1421
--- /dev/null
+++ b/arch/arm/kernel/perf_event.c
@@ -0,0 +1,775 @@
+#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. Callchain code is based on the ARM OProfile backtrace
+ * code.
+ */
+#define pr_fmt(fmt) "hw perfevents: " fmt
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/perf_event.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+
+#include <asm/cputype.h>
+#include <asm/irq.h>
+#include <asm/irq_regs.h>
+#include <asm/pmu.h>
+#include <asm/stacktrace.h>
+
+static struct platform_device *pmu_device;
+
+/*
+ * Hardware lock to serialize accesses to PMU registers. Needed for the
+ * read/modify/write sequences.
+ */
+static DEFINE_RAW_SPINLOCK(pmu_lock);
+
+/*
+ * ARMv6 supports a maximum of 3 events, starting from index 1. If we add
+ * another platform that supports more, we need to increase this to be the
+ * largest of all platforms.
+ *
+ * ARMv7 supports up to 32 events:
+ *  cycle counter CCNT + 31 events counters CNT0..30.
+ *  Cortex-A8 has 1+4 counters, Cortex-A9 has 1+6 counters.
+ */
+#define ARMPMU_MAX_HWEVENTS		33
+
+/* The events for a given CPU. */
+struct cpu_hw_events {
+	/*
+	 * The events that are active on the CPU for the given index. Index 0
+	 * is reserved.
+	 */
+	struct perf_event	*events[ARMPMU_MAX_HWEVENTS];
+
+	/*
+	 * A 1 bit for an index indicates that the counter is being used for
+	 * an event. A 0 means that the counter can be used.
+	 */
+	unsigned long		used_mask[BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)];
+
+	/*
+	 * A 1 bit for an index indicates that the counter is actively being
+	 * used.
+	 */
+	unsigned long		active_mask[BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)];
+};
+static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
+
+struct arm_pmu {
+	enum arm_perf_pmu_ids id;
+	const char	*name;
+	irqreturn_t	(*handle_irq)(int irq_num, void *dev);
+	void		(*enable)(struct hw_perf_event *evt, int idx);
+	void		(*disable)(struct hw_perf_event *evt, int idx);
+	int		(*get_event_idx)(struct cpu_hw_events *cpuc,
+					 struct hw_perf_event *hwc);
+	u32		(*read_counter)(int idx);
+	void		(*write_counter)(int idx, u32 val);
+	void		(*start)(void);
+	void		(*stop)(void);
+	void		(*reset)(void *);
+	const unsigned	(*cache_map)[PERF_COUNT_HW_CACHE_MAX]
+				    [PERF_COUNT_HW_CACHE_OP_MAX]
+				    [PERF_COUNT_HW_CACHE_RESULT_MAX];
+	const unsigned	(*event_map)[PERF_COUNT_HW_MAX];
+	u32		raw_event_mask;
+	int		num_events;
+	u64		max_period;
+};
+
+/* Set at runtime when we know what CPU type we are. */
+static const struct arm_pmu *armpmu;
+
+enum arm_perf_pmu_ids
+armpmu_get_pmu_id(void)
+{
+	int id = -ENODEV;
+
+	if (armpmu != NULL)
+		id = armpmu->id;
+
+	return id;
+}
+EXPORT_SYMBOL_GPL(armpmu_get_pmu_id);
+
+int
+armpmu_get_max_events(void)
+{
+	int max_events = 0;
+
+	if (armpmu != NULL)
+		max_events = armpmu->num_events;
+
+	return max_events;
+}
+EXPORT_SYMBOL_GPL(armpmu_get_max_events);
+
+int perf_num_counters(void)
+{
+	return armpmu_get_max_events();
+}
+EXPORT_SYMBOL_GPL(perf_num_counters);
+
+#define HW_OP_UNSUPPORTED		0xFFFF
+
+#define C(_x) \
+	PERF_COUNT_HW_CACHE_##_x
+
+#define CACHE_OP_UNSUPPORTED		0xFFFF
+
+static int
+armpmu_map_cache_event(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)(*armpmu->cache_map)[cache_type][cache_op][cache_result];
+
+	if (ret == CACHE_OP_UNSUPPORTED)
+		return -ENOENT;
+
+	return ret;
+}
+
+static int
+armpmu_map_event(u64 config)
+{
+	int mapping = (*armpmu->event_map)[config];
+	return mapping == HW_OP_UNSUPPORTED ? -EOPNOTSUPP : mapping;
+}
+
+static int
+armpmu_map_raw_event(u64 config)
+{
+	return (int)(config & armpmu->raw_event_mask);
+}
+
+static int
+armpmu_event_set_period(struct perf_event *event,
+			struct hw_perf_event *hwc,
+			int idx)
+{
+	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;
+	}
+
+	if (left > (s64)armpmu->max_period)
+		left = armpmu->max_period;
+
+	local64_set(&hwc->prev_count, (u64)-left);
+
+	armpmu->write_counter(idx, (u64)(-left) & 0xffffffff);
+
+	perf_event_update_userpage(event);
+
+	return ret;
+}
+
+static u64
+armpmu_event_update(struct perf_event *event,
+		    struct hw_perf_event *hwc,
+		    int idx, int overflow)
+{
+	u64 delta, prev_raw_count, new_raw_count;
+
+again:
+	prev_raw_count = local64_read(&hwc->prev_count);
+	new_raw_count = armpmu->read_counter(idx);
+
+	if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
+			     new_raw_count) != prev_raw_count)
+		goto again;
+
+	new_raw_count &= armpmu->max_period;
+	prev_raw_count &= armpmu->max_period;
+
+	if (overflow)
+		delta = armpmu->max_period - prev_raw_count + new_raw_count + 1;
+	else
+		delta = new_raw_count - prev_raw_count;
+
+	local64_add(delta, &event->count);
+	local64_sub(delta, &hwc->period_left);
+
+	return new_raw_count;
+}
+
+static void
+armpmu_read(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+
+	/* Don't read disabled counters! */
+	if (hwc->idx < 0)
+		return;
+
+	armpmu_event_update(event, hwc, hwc->idx, 0);
+}
+
+static void
+armpmu_stop(struct perf_event *event, int flags)
+{
+	struct hw_perf_event *hwc = &event->hw;
+
+	if (!armpmu)
+		return;
+
+	/*
+	 * 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(hwc, hwc->idx);
+		barrier(); /* why? */
+		armpmu_event_update(event, hwc, hwc->idx, 0);
+		hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
+	}
+}
+
+static void
+armpmu_start(struct perf_event *event, int flags)
+{
+	struct hw_perf_event *hwc = &event->hw;
+
+	if (!armpmu)
+		return;
+
+	/*
+	 * 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, hwc, hwc->idx);
+	armpmu->enable(hwc, hwc->idx);
+}
+
+static void
+armpmu_del(struct perf_event *event, int flags)
+{
+	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+	struct hw_perf_event *hwc = &event->hw;
+	int idx = hwc->idx;
+
+	WARN_ON(idx < 0);
+
+	clear_bit(idx, cpuc->active_mask);
+	armpmu_stop(event, PERF_EF_UPDATE);
+	cpuc->events[idx] = NULL;
+	clear_bit(idx, cpuc->used_mask);
+
+	perf_event_update_userpage(event);
+}
+
+static int
+armpmu_add(struct perf_event *event, int flags)
+{
+	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_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(cpuc, hwc);
+	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(hwc, idx);
+	cpuc->events[idx] = event;
+	set_bit(idx, cpuc->active_mask);
+
+	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 struct pmu pmu;
+
+static int
+validate_event(struct cpu_hw_events *cpuc,
+	       struct perf_event *event)
+{
+	struct hw_perf_event fake_event = event->hw;
+
+	if (event->pmu != &pmu || event->state <= PERF_EVENT_STATE_OFF)
+		return 1;
+
+	return armpmu->get_event_idx(cpuc, &fake_event) >= 0;
+}
+
+static int
+validate_group(struct perf_event *event)
+{
+	struct perf_event *sibling, *leader = event->group_leader;
+	struct cpu_hw_events fake_pmu;
+
+	memset(&fake_pmu, 0, sizeof(fake_pmu));
+
+	if (!validate_event(&fake_pmu, leader))
+		return -ENOSPC;
+
+	list_for_each_entry(sibling, &leader->sibling_list, group_entry) {
+		if (!validate_event(&fake_pmu, sibling))
+			return -ENOSPC;
+	}
+
+	if (!validate_event(&fake_pmu, event))
+		return -ENOSPC;
+
+	return 0;
+}
+
+static irqreturn_t armpmu_platform_irq(int irq, void *dev)
+{
+	struct arm_pmu_platdata *plat = dev_get_platdata(&pmu_device->dev);
+
+	return plat->handle_irq(irq, dev, armpmu->handle_irq);
+}
+
+static int
+armpmu_reserve_hardware(void)
+{
+	struct arm_pmu_platdata *plat;
+	irq_handler_t handle_irq;
+	int i, err = -ENODEV, irq;
+
+	pmu_device = reserve_pmu(ARM_PMU_DEVICE_CPU);
+	if (IS_ERR(pmu_device)) {
+		pr_warning("unable to reserve pmu\n");
+		return PTR_ERR(pmu_device);
+	}
+
+	init_pmu(ARM_PMU_DEVICE_CPU);
+
+	plat = dev_get_platdata(&pmu_device->dev);
+	if (plat && plat->handle_irq)
+		handle_irq = armpmu_platform_irq;
+	else
+		handle_irq = armpmu->handle_irq;
+
+	if (pmu_device->num_resources < 1) {
+		pr_err("no irqs for PMUs defined\n");
+		return -ENODEV;
+	}
+
+	for (i = 0; i < pmu_device->num_resources; ++i) {
+		irq = platform_get_irq(pmu_device, i);
+		if (irq < 0)
+			continue;
+
+		err = request_irq(irq, handle_irq,
+				  IRQF_DISABLED | IRQF_NOBALANCING,
+				  "armpmu", NULL);
+		if (err) {
+			pr_warning("unable to request IRQ%d for ARM perf "
+				"counters\n", irq);
+			break;
+		}
+	}
+
+	if (err) {
+		for (i = i - 1; i >= 0; --i) {
+			irq = platform_get_irq(pmu_device, i);
+			if (irq >= 0)
+				free_irq(irq, NULL);
+		}
+		release_pmu(pmu_device);
+		pmu_device = NULL;
+	}
+
+	return err;
+}
+
+static void
+armpmu_release_hardware(void)
+{
+	int i, irq;
+
+	for (i = pmu_device->num_resources - 1; i >= 0; --i) {
+		irq = platform_get_irq(pmu_device, i);
+		if (irq >= 0)
+			free_irq(irq, NULL);
+	}
+	armpmu->stop();
+
+	release_pmu(pmu_device);
+	pmu_device = NULL;
+}
+
+static atomic_t active_events = ATOMIC_INIT(0);
+static DEFINE_MUTEX(pmu_reserve_mutex);
+
+static void
+hw_perf_event_destroy(struct perf_event *event)
+{
+	if (atomic_dec_and_mutex_lock(&active_events, &pmu_reserve_mutex)) {
+		armpmu_release_hardware();
+		mutex_unlock(&pmu_reserve_mutex);
+	}
+}
+
+static int
+__hw_perf_event_init(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	int mapping, err;
+
+	/* Decode the generic type into an ARM event identifier. */
+	if (PERF_TYPE_HARDWARE == event->attr.type) {
+		mapping = armpmu_map_event(event->attr.config);
+	} else if (PERF_TYPE_HW_CACHE == event->attr.type) {
+		mapping = armpmu_map_cache_event(event->attr.config);
+	} else if (PERF_TYPE_RAW == event->attr.type) {
+		mapping = armpmu_map_raw_event(event->attr.config);
+	} else {
+		pr_debug("event type %x not supported\n", event->attr.type);
+		return -EOPNOTSUPP;
+	}
+
+	if (mapping < 0) {
+		pr_debug("event %x:%llx not supported\n", event->attr.type,
+			 event->attr.config);
+		return mapping;
+	}
+
+	/*
+	 * Check whether we need to exclude the counter from certain modes.
+	 * The ARM performance counters are on all of the time so if someone
+	 * has asked us for some excludes then we have to fail.
+	 */
+	if (event->attr.exclude_kernel || event->attr.exclude_user ||
+	    event->attr.exclude_hv || event->attr.exclude_idle) {
+		pr_debug("ARM performance counters do not support "
+			 "mode exclusion\n");
+		return -EPERM;
+	}
+
+	/*
+	 * 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;
+
+	/*
+	 * Store the event encoding into the config_base field. config and
+	 * event_base are unused as the only 2 things we need to know are
+	 * the event mapping and the counter to use. The counter to use is
+	 * also the indx and the config_base is the event type.
+	 */
+	hwc->config_base	    = (unsigned long)mapping;
+	hwc->config		    = 0;
+	hwc->event_base		    = 0;
+
+	if (!hwc->sample_period) {
+		hwc->sample_period  = armpmu->max_period;
+		hwc->last_period    = hwc->sample_period;
+		local64_set(&hwc->period_left, hwc->sample_period);
+	}
+
+	err = 0;
+	if (event->group_leader != event) {
+		err = validate_group(event);
+		if (err)
+			return -EINVAL;
+	}
+
+	return err;
+}
+
+static int armpmu_event_init(struct perf_event *event)
+{
+	int err = 0;
+
+	switch (event->attr.type) {
+	case PERF_TYPE_RAW:
+	case PERF_TYPE_HARDWARE:
+	case PERF_TYPE_HW_CACHE:
+		break;
+
+	default:
+		return -ENOENT;
+	}
+
+	if (!armpmu)
+		return -ENODEV;
+
+	event->destroy = hw_perf_event_destroy;
+
+	if (!atomic_inc_not_zero(&active_events)) {
+		mutex_lock(&pmu_reserve_mutex);
+		if (atomic_read(&active_events) == 0) {
+			err = armpmu_reserve_hardware();
+		}
+
+		if (!err)
+			atomic_inc(&active_events);
+		mutex_unlock(&pmu_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)
+{
+	/* Enable all of the perf events on hardware. */
+	int idx, enabled = 0;
+	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+
+	if (!armpmu)
+		return;
+
+	for (idx = 0; idx <= armpmu->num_events; ++idx) {
+		struct perf_event *event = cpuc->events[idx];
+
+		if (!event)
+			continue;
+
+		armpmu->enable(&event->hw, idx);
+		enabled = 1;
+	}
+
+	if (enabled)
+		armpmu->start();
+}
+
+static void armpmu_disable(struct pmu *pmu)
+{
+	if (armpmu)
+		armpmu->stop();
+}
+
+static struct pmu 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,
+};
+
+/* Include the PMU-specific implementations. */
+#include "perf_event_xscale.c"
+#include "perf_event_v6.c"
+#include "perf_event_v7.c"
+
+/*
+ * Ensure the PMU has sane values out of reset.
+ * This requires SMP to be available, so exists as a separate initcall.
+ */
+static int __init
+armpmu_reset(void)
+{
+	if (armpmu && armpmu->reset)
+		return on_each_cpu(armpmu->reset, NULL, 1);
+	return 0;
+}
+arch_initcall(armpmu_reset);
+
+static int __init
+init_hw_perf_events(void)
+{
+	unsigned long cpuid = read_cpuid_id();
+	unsigned long implementor = (cpuid & 0xFF000000) >> 24;
+	unsigned long part_number = (cpuid & 0xFFF0);
+
+	/* ARM Ltd CPUs. */
+	if (0x41 == implementor) {
+		switch (part_number) {
+		case 0xB360:	/* ARM1136 */
+		case 0xB560:	/* ARM1156 */
+		case 0xB760:	/* ARM1176 */
+			armpmu = armv6pmu_init();
+			break;
+		case 0xB020:	/* ARM11mpcore */
+			armpmu = armv6mpcore_pmu_init();
+			break;
+		case 0xC080:	/* Cortex-A8 */
+			armpmu = armv7_a8_pmu_init();
+			break;
+		case 0xC090:	/* Cortex-A9 */
+			armpmu = armv7_a9_pmu_init();
+			break;
+		}
+	/* Intel CPUs [xscale]. */
+	} else if (0x69 == implementor) {
+		part_number = (cpuid >> 13) & 0x7;
+		switch (part_number) {
+		case 1:
+			armpmu = xscale1pmu_init();
+			break;
+		case 2:
+			armpmu = xscale2pmu_init();
+			break;
+		}
+	}
+
+	if (armpmu) {
+		pr_info("enabled with %s PMU driver, %d counters available\n",
+			armpmu->name, armpmu->num_events);
+	} else {
+		pr_info("no hardware support available\n");
+	}
+
+	perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
+
+	return 0;
+}
+early_initcall(init_hw_perf_events);
+
+/*
+ * Callchain handling code.
+ */
+
+/*
+ * The registers we're interested in are at the end of the variable
+ * length saved register structure. The fp points at the end of this
+ * structure so the address of this struct is:
+ * (struct frame_tail *)(xxx->fp)-1
+ *
+ * This code has been adapted from the ARM OProfile support.
+ */
+struct frame_tail {
+	struct frame_tail __user *fp;
+	unsigned long sp;
+	unsigned long lr;
+} __attribute__((packed));
+
+/*
+ * Get the return address for a single stackframe and return a pointer to the
+ * next frame tail.
+ */
+static struct frame_tail __user *
+user_backtrace(struct frame_tail __user *tail,
+	       struct perf_callchain_entry *entry)
+{
+	struct frame_tail buftail;
+
+	/* Also check accessibility of one struct frame_tail beyond */
+	if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
+		return NULL;
+	if (__copy_from_user_inatomic(&buftail, tail, sizeof(buftail)))
+		return NULL;
+
+	perf_callchain_store(entry, buftail.lr);
+
+	/*
+	 * Frame pointers should strictly progress back up the stack
+	 * (towards higher addresses).
+	 */
+	if (tail + 1 >= buftail.fp)
+		return NULL;
+
+	return buftail.fp - 1;
+}
+
+void
+perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
+{
+	struct frame_tail __user *tail;
+
+
+	tail = (struct frame_tail __user *)regs->ARM_fp - 1;
+
+	while ((entry->nr < PERF_MAX_STACK_DEPTH) &&
+	       tail && !((unsigned long)tail & 0x3))
+		tail = user_backtrace(tail, entry);
+}
+
+/*
+ * Gets called by walk_stackframe() for every stackframe. This will be called
+ * whist unwinding the stackframe and is like a subroutine return so we use
+ * the PC.
+ */
+static int
+callchain_trace(struct stackframe *fr,
+		void *data)
+{
+	struct perf_callchain_entry *entry = data;
+	perf_callchain_store(entry, fr->pc);
+	return 0;
+}
+
+void
+perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
+{
+	struct stackframe fr;
+
+	fr.fp = regs->ARM_fp;
+	fr.sp = regs->ARM_sp;
+	fr.lr = regs->ARM_lr;
+	fr.pc = regs->ARM_pc;
+	walk_stackframe(&fr, callchain_trace, entry);
+}