- 根目录:
- arch
- arc
- kernel
- perf_event.c
/*
* Linux performance counter support for ARC700 series
*
* Copyright (C) 2013-2015 Synopsys, Inc. (www.synopsys.com)
*
* This code is inspired by the perf support of various other architectures.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/perf_event.h>
#include <linux/platform_device.h>
#include <asm/arcregs.h>
#include <asm/stacktrace.h>
struct arc_pmu {
struct pmu pmu;
unsigned int irq;
int n_counters;
u64 max_period;
int ev_hw_idx[PERF_COUNT_ARC_HW_MAX];
};
struct arc_pmu_cpu {
/*
* 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(ARC_PERF_MAX_COUNTERS)];
/*
* The events that are active on the PMU for the given index.
*/
struct perf_event *act_counter[ARC_PERF_MAX_COUNTERS];
};
struct arc_callchain_trace {
int depth;
void *perf_stuff;
};
static int callchain_trace(unsigned int addr, void *data)
{
struct arc_callchain_trace *ctrl = data;
struct perf_callchain_entry *entry = ctrl->perf_stuff;
perf_callchain_store(entry, addr);
if (ctrl->depth++ < 3)
return 0;
return -1;
}
void
perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
{
struct arc_callchain_trace ctrl = {
.depth = 0,
.perf_stuff = entry,
};
arc_unwind_core(NULL, regs, callchain_trace, &ctrl);
}
void
perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
{
/*
* User stack can't be unwound trivially with kernel dwarf unwinder
* So for now just record the user PC
*/
perf_callchain_store(entry, instruction_pointer(regs));
}
static struct arc_pmu *arc_pmu;
static DEFINE_PER_CPU(struct arc_pmu_cpu, arc_pmu_cpu);
/* read counter #idx; note that counter# != event# on ARC! */
static uint64_t arc_pmu_read_counter(int idx)
{
uint32_t tmp;
uint64_t result;
/*
* ARC supports making 'snapshots' of the counters, so we don't
* need to care about counters wrapping to 0 underneath our feet
*/
write_aux_reg(ARC_REG_PCT_INDEX, idx);
tmp = read_aux_reg(ARC_REG_PCT_CONTROL);
write_aux_reg(ARC_REG_PCT_CONTROL, tmp | ARC_REG_PCT_CONTROL_SN);
result = (uint64_t) (read_aux_reg(ARC_REG_PCT_SNAPH)) << 32;
result |= read_aux_reg(ARC_REG_PCT_SNAPL);
return result;
}
static void arc_perf_event_update(struct perf_event *event,
struct hw_perf_event *hwc, int idx)
{
uint64_t prev_raw_count = local64_read(&hwc->prev_count);
uint64_t new_raw_count = arc_pmu_read_counter(idx);
int64_t delta = new_raw_count - prev_raw_count;
/*
* We don't afaraid of hwc->prev_count changing beneath our feet
* because there's no way for us to re-enter this function anytime.
*/
local64_set(&hwc->prev_count, new_raw_count);
local64_add(delta, &event->count);
local64_sub(delta, &hwc->period_left);
}
static void arc_pmu_read(struct perf_event *event)
{
arc_perf_event_update(event, &event->hw, event->hw.idx);
}
static int arc_pmu_cache_event(u64 config)
{
unsigned int cache_type, cache_op, cache_result;
int ret;
cache_type = (config >> 0) & 0xff;
cache_op = (config >> 8) & 0xff;
cache_result = (config >> 16) & 0xff;
if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
return -EINVAL;
if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
return -EINVAL;
if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
return -EINVAL;
ret = arc_pmu_cache_map[cache_type][cache_op][cache_result];
if (ret == CACHE_OP_UNSUPPORTED)
return -ENOENT;
pr_debug("init cache event: type/op/result %d/%d/%d with h/w %d \'%s\'\n",
cache_type, cache_op, cache_result, ret,
arc_pmu_ev_hw_map[ret]);
return ret;
}
/* initializes hw_perf_event structure if event is supported */
static int arc_pmu_event_init(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
int ret;
if (!is_sampling_event(event)) {
hwc->sample_period = arc_pmu->max_period;
hwc->last_period = hwc->sample_period;
local64_set(&hwc->period_left, hwc->sample_period);
}
hwc->config = 0;
if (is_isa_arcv2()) {
/* "exclude user" means "count only kernel" */
if (event->attr.exclude_user)
hwc->config |= ARC_REG_PCT_CONFIG_KERN;
/* "exclude kernel" means "count only user" */
if (event->attr.exclude_kernel)
hwc->config |= ARC_REG_PCT_CONFIG_USER;
}
switch (event->attr.type) {
case PERF_TYPE_HARDWARE:
if (event->attr.config >= PERF_COUNT_HW_MAX)
return -ENOENT;
if (arc_pmu->ev_hw_idx[event->attr.config] < 0)
return -ENOENT;
hwc->config |= arc_pmu->ev_hw_idx[event->attr.config];
pr_debug("init event %d with h/w %d \'%s\'\n",
(int) event->attr.config, (int) hwc->config,
arc_pmu_ev_hw_map[event->attr.config]);
return 0;
case PERF_TYPE_HW_CACHE:
ret = arc_pmu_cache_event(event->attr.config);
if (ret < 0)
return ret;
hwc->config |= arc_pmu->ev_hw_idx[ret];
return 0;
default:
return -ENOENT;
}
}
/* starts all counters */
static void arc_pmu_enable(struct pmu *pmu)
{
uint32_t tmp;
tmp = read_aux_reg(ARC_REG_PCT_CONTROL);
write_aux_reg(ARC_REG_PCT_CONTROL, (tmp & 0xffff0000) | 0x1);
}
/* stops all counters */
static void arc_pmu_disable(struct pmu *pmu)
{
uint32_t tmp;
tmp = read_aux_reg(ARC_REG_PCT_CONTROL);
write_aux_reg(ARC_REG_PCT_CONTROL, (tmp & 0xffff0000) | 0x0);
}
static int arc_pmu_event_set_period(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
s64 left = local64_read(&hwc->period_left);
s64 period = hwc->sample_period;
int idx = hwc->idx;
int overflow = 0;
u64 value;
if (unlikely(left <= -period)) {
/* left underflowed by more than period. */
left = period;
local64_set(&hwc->period_left, left);
hwc->last_period = period;
overflow = 1;
} else if (unlikely(left <= 0)) {
/* left underflowed by less than period. */
left += period;
local64_set(&hwc->period_left, left);
hwc->last_period = period;
overflow = 1;
}
if (left > arc_pmu->max_period)
left = arc_pmu->max_period;
value = arc_pmu->max_period - left;
local64_set(&hwc->prev_count, value);
/* Select counter */
write_aux_reg(ARC_REG_PCT_INDEX, idx);
/* Write value */
write_aux_reg(ARC_REG_PCT_COUNTL, (u32)value);
write_aux_reg(ARC_REG_PCT_COUNTH, (value >> 32));
perf_event_update_userpage(event);
return overflow;
}
/*
* Assigns hardware counter to hardware condition.
* Note that there is no separate start/stop mechanism;
* stopping is achieved by assigning the 'never' condition
*/
static void arc_pmu_start(struct perf_event *event, int flags)
{
struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
if (WARN_ON_ONCE(idx == -1))
return;
if (flags & PERF_EF_RELOAD)
WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
hwc->state = 0;
arc_pmu_event_set_period(event);
/* Enable interrupt for this counter */
if (is_sampling_event(event))
write_aux_reg(ARC_REG_PCT_INT_CTRL,
read_aux_reg(ARC_REG_PCT_INT_CTRL) | (1 << idx));
/* enable ARC pmu here */
write_aux_reg(ARC_REG_PCT_INDEX, idx); /* counter # */
write_aux_reg(ARC_REG_PCT_CONFIG, hwc->config); /* condition */
}
static void arc_pmu_stop(struct perf_event *event, int flags)
{
struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
/* Disable interrupt for this counter */
if (is_sampling_event(event)) {
/*
* Reset interrupt flag by writing of 1. This is required
* to make sure pending interrupt was not left.
*/
write_aux_reg(ARC_REG_PCT_INT_ACT, 1 << idx);
write_aux_reg(ARC_REG_PCT_INT_CTRL,
read_aux_reg(ARC_REG_PCT_INT_CTRL) & ~(1 << idx));
}
if (!(event->hw.state & PERF_HES_STOPPED)) {
/* stop ARC pmu here */
write_aux_reg(ARC_REG_PCT_INDEX, idx);
/* condition code #0 is always "never" */
write_aux_reg(ARC_REG_PCT_CONFIG, 0);
event->hw.state |= PERF_HES_STOPPED;
}
if ((flags & PERF_EF_UPDATE) &&
!(event->hw.state & PERF_HES_UPTODATE)) {
arc_perf_event_update(event, &event->hw, idx);
event->hw.state |= PERF_HES_UPTODATE;
}
}
static void arc_pmu_del(struct perf_event *event, int flags)
{
struct arc_pmu_cpu *pmu_cpu = this_cpu_ptr(&arc_pmu_cpu);
arc_pmu_stop(event, PERF_EF_UPDATE);
__clear_bit(event->hw.idx, pmu_cpu->used_mask);
pmu_cpu->act_counter[event->hw.idx] = 0;
perf_event_update_userpage(event);
}
/* allocate hardware counter and optionally start counting */
static int arc_pmu_add(struct perf_event *event, int flags)
{
struct arc_pmu_cpu *pmu_cpu = this_cpu_ptr(&arc_pmu_cpu);
struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
if (__test_and_set_bit(idx, pmu_cpu->used_mask)) {
idx = find_first_zero_bit(pmu_cpu->used_mask,
arc_pmu->n_counters);
if (idx == arc_pmu->n_counters)
return -EAGAIN;
__set_bit(idx, pmu_cpu->used_mask);
hwc->idx = idx;
}
write_aux_reg(ARC_REG_PCT_INDEX, idx);
pmu_cpu->act_counter[idx] = event;
if (is_sampling_event(event)) {
/* Mimic full counter overflow as other arches do */
write_aux_reg(ARC_REG_PCT_INT_CNTL, (u32)arc_pmu->max_period);
write_aux_reg(ARC_REG_PCT_INT_CNTH,
(arc_pmu->max_period >> 32));
}
write_aux_reg(ARC_REG_PCT_CONFIG, 0);
write_aux_reg(ARC_REG_PCT_COUNTL, 0);
write_aux_reg(ARC_REG_PCT_COUNTH, 0);
local64_set(&hwc->prev_count, 0);
hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
if (flags & PERF_EF_START)
arc_pmu_start(event, PERF_EF_RELOAD);
perf_event_update_userpage(event);
return 0;
}
#ifdef CONFIG_ISA_ARCV2
static irqreturn_t arc_pmu_intr(int irq, void *dev)
{
struct perf_sample_data data;
struct arc_pmu_cpu *pmu_cpu = this_cpu_ptr(&arc_pmu_cpu);
struct pt_regs *regs;
int active_ints;
int idx;
arc_pmu_disable(&arc_pmu->pmu);
active_ints = read_aux_reg(ARC_REG_PCT_INT_ACT);
regs = get_irq_regs();
for (idx = 0; idx < arc_pmu->n_counters; idx++) {
struct perf_event *event = pmu_cpu->act_counter[idx];
struct hw_perf_event *hwc;
if (!(active_ints & (1 << idx)))
continue;
/* Reset interrupt flag by writing of 1 */
write_aux_reg(ARC_REG_PCT_INT_ACT, 1 << idx);
/*
* On reset of "interrupt active" bit corresponding
* "interrupt enable" bit gets automatically reset as well.
* Now we need to re-enable interrupt for the counter.
*/
write_aux_reg(ARC_REG_PCT_INT_CTRL,
read_aux_reg(ARC_REG_PCT_INT_CTRL) | (1 << idx));
hwc = &event->hw;
WARN_ON_ONCE(hwc->idx != idx);
arc_perf_event_update(event, &event->hw, event->hw.idx);
perf_sample_data_init(&data, 0, hwc->last_period);
if (!arc_pmu_event_set_period(event))
continue;
if (perf_event_overflow(event, &data, regs))
arc_pmu_stop(event, 0);
}
arc_pmu_enable(&arc_pmu->pmu);
return IRQ_HANDLED;
}
#else
static irqreturn_t arc_pmu_intr(int irq, void *dev)
{
return IRQ_NONE;
}
#endif /* CONFIG_ISA_ARCV2 */
static void arc_cpu_pmu_irq_init(void *data)
{
int irq = *(int *)data;
enable_percpu_irq(irq, IRQ_TYPE_NONE);
/* Clear all pending interrupt flags */
write_aux_reg(ARC_REG_PCT_INT_ACT, 0xffffffff);
}
static int arc_pmu_device_probe(struct platform_device *pdev)
{
struct arc_reg_pct_build pct_bcr;
struct arc_reg_cc_build cc_bcr;
int i, j, has_interrupts;
int counter_size; /* in bits */
union cc_name {
struct {
uint32_t word0, word1;
char sentinel;
} indiv;
char str[9];
} cc_name;
READ_BCR(ARC_REG_PCT_BUILD, pct_bcr);
if (!pct_bcr.v) {
pr_err("This core does not have performance counters!\n");
return -ENODEV;
}
BUG_ON(pct_bcr.c > ARC_PERF_MAX_COUNTERS);
READ_BCR(ARC_REG_CC_BUILD, cc_bcr);
BUG_ON(!cc_bcr.v); /* Counters exist but No countable conditions ? */
arc_pmu = devm_kzalloc(&pdev->dev, sizeof(struct arc_pmu), GFP_KERNEL);
if (!arc_pmu)
return -ENOMEM;
has_interrupts = is_isa_arcv2() ? pct_bcr.i : 0;
arc_pmu->n_counters = pct_bcr.c;
counter_size = 32 + (pct_bcr.s << 4);
arc_pmu->max_period = (1ULL << counter_size) / 2 - 1ULL;
pr_info("ARC perf\t: %d counters (%d bits), %d conditions%s\n",
arc_pmu->n_counters, counter_size, cc_bcr.c,
has_interrupts ? ", [overflow IRQ support]":"");
cc_name.str[8] = 0;
for (i = 0; i < PERF_COUNT_ARC_HW_MAX; i++)
arc_pmu->ev_hw_idx[i] = -1;
/* loop thru all available h/w condition indexes */
for (j = 0; j < cc_bcr.c; j++) {
write_aux_reg(ARC_REG_CC_INDEX, j);
cc_name.indiv.word0 = read_aux_reg(ARC_REG_CC_NAME0);
cc_name.indiv.word1 = read_aux_reg(ARC_REG_CC_NAME1);
/* See if it has been mapped to a perf event_id */
for (i = 0; i < ARRAY_SIZE(arc_pmu_ev_hw_map); i++) {
if (arc_pmu_ev_hw_map[i] &&
!strcmp(arc_pmu_ev_hw_map[i], cc_name.str) &&
strlen(arc_pmu_ev_hw_map[i])) {
pr_debug("mapping perf event %2d to h/w event \'%8s\' (idx %d)\n",
i, cc_name.str, j);
arc_pmu->ev_hw_idx[i] = j;
}
}
}
arc_pmu->pmu = (struct pmu) {
.pmu_enable = arc_pmu_enable,
.pmu_disable = arc_pmu_disable,
.event_init = arc_pmu_event_init,
.add = arc_pmu_add,
.del = arc_pmu_del,
.start = arc_pmu_start,
.stop = arc_pmu_stop,
.read = arc_pmu_read,
};
if (has_interrupts) {
int irq = platform_get_irq(pdev, 0);
if (irq < 0) {
pr_err("Cannot get IRQ number for the platform\n");
return -ENODEV;
}
arc_pmu->irq = irq;
/* intc map function ensures irq_set_percpu_devid() called */
request_percpu_irq(irq, arc_pmu_intr, "ARC perf counters",
this_cpu_ptr(&arc_pmu_cpu));
on_each_cpu(arc_cpu_pmu_irq_init, &irq, 1);
} else
arc_pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
return perf_pmu_register(&arc_pmu->pmu, pdev->name, PERF_TYPE_RAW);
}
#ifdef CONFIG_OF
static const struct of_device_id arc_pmu_match[] = {
{ .compatible = "snps,arc700-pct" },
{ .compatible = "snps,archs-pct" },
{},
};
MODULE_DEVICE_TABLE(of, arc_pmu_match);
#endif
static struct platform_driver arc_pmu_driver = {
.driver = {
.name = "arc-pct",
.of_match_table = of_match_ptr(arc_pmu_match),
},
.probe = arc_pmu_device_probe,
};
module_platform_driver(arc_pmu_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mischa Jonker <mjonker@synopsys.com>");
MODULE_DESCRIPTION("ARC PMU driver");