- 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/kernel.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/uaccess.h>
#include <asm/irq_regs.h>
#include <asm/pmu.h>
#include <asm/stacktrace.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;
switch (event->attr.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;
}
if (left > (s64)armpmu->max_period)
left = armpmu->max_period;
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 = armpmu->get_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);
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, 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_hw_events *hw_events,
struct perf_event *event)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
if (is_software_event(event))
return 1;
if (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, 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_dispatch_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);
if (plat && plat->handle_irq)
return plat->handle_irq(irq, dev, armpmu->handle_irq);
else
return armpmu->handle_irq(irq, dev);
}
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 (!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);
}
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 = armpmu->get_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_RUNTIME
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);
}
/*
* 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;
if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
/* We don't support guest os callchain now */
return;
}
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;
if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
/* We don't support guest os callchain now */
return;
}
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);
}
unsigned long perf_instruction_pointer(struct pt_regs *regs)
{
if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
return perf_guest_cbs->get_guest_ip();
return instruction_pointer(regs);
}
unsigned long perf_misc_flags(struct pt_regs *regs)
{
int misc = 0;
if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
if (perf_guest_cbs->is_user_mode())
misc |= PERF_RECORD_MISC_GUEST_USER;
else
misc |= PERF_RECORD_MISC_GUEST_KERNEL;
} else {
if (user_mode(regs))
misc |= PERF_RECORD_MISC_USER;
else
misc |= PERF_RECORD_MISC_KERNEL;
}
return misc;
}