- 根目录:
- arch
- arm
- kernel
- perf_event.c
#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/bitmap.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/export.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>
/*
* ARMv6 supports a maximum of 3 events, starting from index 0. 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 32
static DEFINE_PER_CPU(struct perf_event * [ARMPMU_MAX_HWEVENTS], hw_events);
static DEFINE_PER_CPU(unsigned long [BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)], used_mask);
static DEFINE_PER_CPU(struct pmu_hw_events, cpu_hw_events);
#define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu))
/* Set at runtime when we know what CPU type we are. */
static struct arm_pmu *cpu_pmu;
enum arm_perf_pmu_ids
armpmu_get_pmu_id(void)
{
int id = -ENODEV;
if (cpu_pmu != NULL)
id = cpu_pmu->id;
return id;
}
EXPORT_SYMBOL_GPL(armpmu_get_pmu_id);
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);
#define HW_OP_UNSUPPORTED 0xFFFF
#define C(_x) \
PERF_COUNT_HW_CACHE_##_x
#define CACHE_OP_UNSUPPORTED 0xFFFF
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_event(const unsigned (*event_map)[PERF_COUNT_HW_MAX], u64 config)
{
int mapping;
if (config >= PERF_COUNT_HW_MAX)
return -ENOENT;
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);
}
static int map_cpu_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;
switch (event->attr.type) {
case PERF_TYPE_HARDWARE:
return armpmu_map_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 hw_perf_event *hwc,
int idx)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
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;
}
u64
armpmu_event_update(struct perf_event *event,
struct hw_perf_event *hwc,
int idx)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
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;
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)
{
struct hw_perf_event *hwc = &event->hw;
/* Don't read disabled counters! */
if (hwc->idx < 0)
return;
armpmu_event_update(event, hwc, hwc->idx);
}
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(hwc, hwc->idx);
barrier(); /* why? */
armpmu_event_update(event, hwc, hwc->idx);
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, hwc, hwc->idx);
armpmu->enable(hwc, hwc->idx);
}
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 = armpmu->get_hw_events();
struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
WARN_ON(idx < 0);
armpmu_stop(event, PERF_EF_UPDATE);
hw_events->events[idx] = NULL;
clear_bit(idx, hw_events->used_mask);
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 = armpmu->get_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, 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);
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_hw_events *hw_events,
struct perf_event *event)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
struct hw_perf_event fake_event = event->hw;
struct pmu *leader_pmu = event->group_leader->pmu;
if (is_software_event(event))
return 1;
if (event->pmu != leader_pmu || event->state < PERF_EVENT_STATE_OFF)
return 1;
if (event->state == PERF_EVENT_STATE_OFF && !event->attr.enable_on_exec)
return 1;
return armpmu->get_event_idx(hw_events, &fake_event) >= 0;
}
static int
validate_group(struct perf_event *event)
{
struct perf_event *sibling, *leader = event->group_leader;
struct pmu_hw_events fake_pmu;
DECLARE_BITMAP(fake_used_mask, ARMPMU_MAX_HWEVENTS);
/*
* Initialise the fake PMU. We only need to populate the
* used_mask for the purposes of validation.
*/
memset(fake_used_mask, 0, sizeof(fake_used_mask));
fake_pmu.used_mask = fake_used_mask;
if (!validate_event(&fake_pmu, leader))
return -EINVAL;
list_for_each_entry(sibling, &leader->sibling_list, group_entry) {
if (!validate_event(&fake_pmu, sibling))
return -EINVAL;
}
if (!validate_event(&fake_pmu, event))
return -EINVAL;
return 0;
}
static irqreturn_t armpmu_platform_irq(int irq, void *dev)
{
struct arm_pmu *armpmu = (struct arm_pmu *) dev;
struct platform_device *plat_device = armpmu->plat_device;
struct arm_pmu_platdata *plat = dev_get_platdata(&plat_device->dev);
return plat->handle_irq(irq, dev, armpmu->handle_irq);
}
static void
armpmu_release_hardware(struct arm_pmu *armpmu)
{
int i, irq, irqs;
struct platform_device *pmu_device = armpmu->plat_device;
struct arm_pmu_platdata *plat =
dev_get_platdata(&pmu_device->dev);
irqs = min(pmu_device->num_resources, num_possible_cpus());
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 (plat && plat->disable_irq)
plat->disable_irq(irq);
free_irq(irq, armpmu);
}
}
release_pmu(armpmu->type);
}
static int
armpmu_reserve_hardware(struct arm_pmu *armpmu)
{
struct arm_pmu_platdata *plat;
irq_handler_t handle_irq;
int i, err, irq, irqs;
struct platform_device *pmu_device = armpmu->plat_device;
if (!pmu_device)
return -ENODEV;
err = reserve_pmu(armpmu->type);
if (err) {
pr_warning("unable to reserve pmu\n");
return err;
}
plat = dev_get_platdata(&pmu_device->dev);
if (plat && plat->handle_irq)
handle_irq = armpmu_platform_irq;
else
handle_irq = armpmu->handle_irq;
irqs = min(pmu_device->num_resources, num_possible_cpus());
if (irqs < 1) {
pr_err("no irqs for PMUs defined\n");
return -ENODEV;
}
for (i = 0; i < irqs; ++i) {
err = 0;
irq = platform_get_irq(pmu_device, i);
if (irq < 0)
continue;
/*
* 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(i)) && irqs > 1) {
pr_warning("unable to set irq affinity (irq=%d, cpu=%u)\n",
irq, i);
continue;
}
err = request_irq(irq, handle_irq,
IRQF_DISABLED | IRQF_NOBALANCING,
"arm-pmu", armpmu);
if (err) {
pr_err("unable to request IRQ%d for ARM PMU counters\n",
irq);
armpmu_release_hardware(armpmu);
return err;
} else if (plat && plat->enable_irq)
plat->enable_irq(irq);
cpumask_set_cpu(i, &armpmu->active_irqs);
}
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, err;
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 -EPERM;
}
/*
* Store the event encoding into the config_base field.
*/
hwc->config_base |= (unsigned long)mapping;
if (!hwc->sample_period) {
/*
* 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);
}
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)
{
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 = armpmu->get_hw_events();
int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events);
if (enabled)
armpmu->start();
}
static void armpmu_disable(struct pmu *pmu)
{
struct arm_pmu *armpmu = to_arm_pmu(pmu);
armpmu->stop();
}
static void __init 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 __init armpmu_register(struct arm_pmu *armpmu, char *name, int type)
{
armpmu_init(armpmu);
return perf_pmu_register(&armpmu->pmu, name, type);
}
/* 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
cpu_pmu_reset(void)
{
if (cpu_pmu && cpu_pmu->reset)
return on_each_cpu(cpu_pmu->reset, NULL, 1);
return 0;
}
arch_initcall(cpu_pmu_reset);
/*
* PMU platform driver and devicetree bindings.
*/
static struct of_device_id armpmu_of_device_ids[] = {
{.compatible = "arm,cortex-a9-pmu"},
{.compatible = "arm,cortex-a8-pmu"},
{.compatible = "arm,arm1136-pmu"},
{.compatible = "arm,arm1176-pmu"},
{},
};
static struct platform_device_id armpmu_plat_device_ids[] = {
{.name = "arm-pmu"},
{},
};
static int __devinit armpmu_device_probe(struct platform_device *pdev)
{
if (!cpu_pmu)
return -ENODEV;
cpu_pmu->plat_device = pdev;
return 0;
}
static struct platform_driver armpmu_driver = {
.driver = {
.name = "arm-pmu",
.of_match_table = armpmu_of_device_ids,
},
.probe = armpmu_device_probe,
.id_table = armpmu_plat_device_ids,
};
static int __init register_pmu_driver(void)
{
return platform_driver_register(&armpmu_driver);
}
device_initcall(register_pmu_driver);
static struct pmu_hw_events *armpmu_get_cpu_events(void)
{
return &__get_cpu_var(cpu_hw_events);
}
static void __init cpu_pmu_init(struct arm_pmu *armpmu)
{
int cpu;
for_each_possible_cpu(cpu) {
struct pmu_hw_events *events = &per_cpu(cpu_hw_events, cpu);
events->events = per_cpu(hw_events, cpu);
events->used_mask = per_cpu(used_mask, cpu);
raw_spin_lock_init(&events->pmu_lock);
}
armpmu->get_hw_events = armpmu_get_cpu_events;
armpmu->type = ARM_PMU_DEVICE_CPU;
}
/*
* 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 __cpuinit pmu_cpu_notify(struct notifier_block *b,
unsigned long action, void *hcpu)
{
if ((action & ~CPU_TASKS_FROZEN) != CPU_STARTING)
return NOTIFY_DONE;
if (cpu_pmu && cpu_pmu->reset)
cpu_pmu->reset(NULL);
return NOTIFY_OK;
}
static struct notifier_block __cpuinitdata pmu_cpu_notifier = {
.notifier_call = pmu_cpu_notify,
};
/*
* CPU PMU identification and registration.
*/
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 */
cpu_pmu = armv6pmu_init();
break;
case 0xB020: /* ARM11mpcore */
cpu_pmu = armv6mpcore_pmu_init();
break;
case 0xC080: /* Cortex-A8 */
cpu_pmu = armv7_a8_pmu_init();
break;
case 0xC090: /* Cortex-A9 */
cpu_pmu = armv7_a9_pmu_init();
break;
case 0xC050: /* Cortex-A5 */
cpu_pmu = armv7_a5_pmu_init();
break;
case 0xC0F0: /* Cortex-A15 */
cpu_pmu = armv7_a15_pmu_init();
break;
case 0xC070: /* Cortex-A7 */
cpu_pmu = armv7_a7_pmu_init();
break;
}
/* Intel CPUs [xscale]. */
} else if (0x69 == implementor) {
part_number = (cpuid >> 13) & 0x7;
switch (part_number) {
case 1:
cpu_pmu = xscale1pmu_init();
break;
case 2:
cpu_pmu = xscale2pmu_init();
break;
}
}
if (cpu_pmu) {
pr_info("enabled with %s PMU driver, %d counters available\n",
cpu_pmu->name, cpu_pmu->num_events);
cpu_pmu_init(cpu_pmu);
register_cpu_notifier(&pmu_cpu_notifier);
armpmu_register(cpu_pmu, "cpu", PERF_TYPE_RAW);
} else {
pr_info("no hardware support available\n");
}
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;
perf_callchain_store(entry, regs->ARM_pc);
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);
}