swh:1:snp:49cd9498d6cccc5e78252c27dcb645bcf7bf0c91
Tip revision: 46cf053efec6a3a5f343fead837777efe8252a46 authored by Linus Torvalds on 23 December 2019, 01:02:23 UTC
Linux 5.5-rc3
Linux 5.5-rc3
Tip revision: 46cf053
oprofile_perf.c
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2010 ARM Ltd.
* Copyright 2012 Advanced Micro Devices, Inc., Robert Richter
*
* Perf-events backend for OProfile.
*/
#include <linux/perf_event.h>
#include <linux/platform_device.h>
#include <linux/oprofile.h>
#include <linux/slab.h>
/*
* Per performance monitor configuration as set via oprofilefs.
*/
struct op_counter_config {
unsigned long count;
unsigned long enabled;
unsigned long event;
unsigned long unit_mask;
unsigned long kernel;
unsigned long user;
struct perf_event_attr attr;
};
static int oprofile_perf_enabled;
static DEFINE_MUTEX(oprofile_perf_mutex);
static struct op_counter_config *counter_config;
static DEFINE_PER_CPU(struct perf_event **, perf_events);
static int num_counters;
/*
* Overflow callback for oprofile.
*/
static void op_overflow_handler(struct perf_event *event,
struct perf_sample_data *data, struct pt_regs *regs)
{
int id;
u32 cpu = smp_processor_id();
for (id = 0; id < num_counters; ++id)
if (per_cpu(perf_events, cpu)[id] == event)
break;
if (id != num_counters)
oprofile_add_sample(regs, id);
else
pr_warn("oprofile: ignoring spurious overflow on cpu %u\n",
cpu);
}
/*
* Called by oprofile_perf_setup to create perf attributes to mirror the oprofile
* settings in counter_config. Attributes are created as `pinned' events and
* so are permanently scheduled on the PMU.
*/
static void op_perf_setup(void)
{
int i;
u32 size = sizeof(struct perf_event_attr);
struct perf_event_attr *attr;
for (i = 0; i < num_counters; ++i) {
attr = &counter_config[i].attr;
memset(attr, 0, size);
attr->type = PERF_TYPE_RAW;
attr->size = size;
attr->config = counter_config[i].event;
attr->sample_period = counter_config[i].count;
attr->pinned = 1;
}
}
static int op_create_counter(int cpu, int event)
{
struct perf_event *pevent;
if (!counter_config[event].enabled || per_cpu(perf_events, cpu)[event])
return 0;
pevent = perf_event_create_kernel_counter(&counter_config[event].attr,
cpu, NULL,
op_overflow_handler, NULL);
if (IS_ERR(pevent))
return PTR_ERR(pevent);
if (pevent->state != PERF_EVENT_STATE_ACTIVE) {
perf_event_release_kernel(pevent);
pr_warn("oprofile: failed to enable event %d on CPU %d\n",
event, cpu);
return -EBUSY;
}
per_cpu(perf_events, cpu)[event] = pevent;
return 0;
}
static void op_destroy_counter(int cpu, int event)
{
struct perf_event *pevent = per_cpu(perf_events, cpu)[event];
if (pevent) {
perf_event_release_kernel(pevent);
per_cpu(perf_events, cpu)[event] = NULL;
}
}
/*
* Called by oprofile_perf_start to create active perf events based on the
* perviously configured attributes.
*/
static int op_perf_start(void)
{
int cpu, event, ret = 0;
for_each_online_cpu(cpu) {
for (event = 0; event < num_counters; ++event) {
ret = op_create_counter(cpu, event);
if (ret)
return ret;
}
}
return ret;
}
/*
* Called by oprofile_perf_stop at the end of a profiling run.
*/
static void op_perf_stop(void)
{
int cpu, event;
for_each_online_cpu(cpu)
for (event = 0; event < num_counters; ++event)
op_destroy_counter(cpu, event);
}
static int oprofile_perf_create_files(struct dentry *root)
{
unsigned int i;
for (i = 0; i < num_counters; i++) {
struct dentry *dir;
char buf[4];
snprintf(buf, sizeof buf, "%d", i);
dir = oprofilefs_mkdir(root, buf);
oprofilefs_create_ulong(dir, "enabled", &counter_config[i].enabled);
oprofilefs_create_ulong(dir, "event", &counter_config[i].event);
oprofilefs_create_ulong(dir, "count", &counter_config[i].count);
oprofilefs_create_ulong(dir, "unit_mask", &counter_config[i].unit_mask);
oprofilefs_create_ulong(dir, "kernel", &counter_config[i].kernel);
oprofilefs_create_ulong(dir, "user", &counter_config[i].user);
}
return 0;
}
static int oprofile_perf_setup(void)
{
raw_spin_lock(&oprofilefs_lock);
op_perf_setup();
raw_spin_unlock(&oprofilefs_lock);
return 0;
}
static int oprofile_perf_start(void)
{
int ret = -EBUSY;
mutex_lock(&oprofile_perf_mutex);
if (!oprofile_perf_enabled) {
ret = 0;
op_perf_start();
oprofile_perf_enabled = 1;
}
mutex_unlock(&oprofile_perf_mutex);
return ret;
}
static void oprofile_perf_stop(void)
{
mutex_lock(&oprofile_perf_mutex);
if (oprofile_perf_enabled)
op_perf_stop();
oprofile_perf_enabled = 0;
mutex_unlock(&oprofile_perf_mutex);
}
#ifdef CONFIG_PM
static int oprofile_perf_suspend(struct platform_device *dev, pm_message_t state)
{
mutex_lock(&oprofile_perf_mutex);
if (oprofile_perf_enabled)
op_perf_stop();
mutex_unlock(&oprofile_perf_mutex);
return 0;
}
static int oprofile_perf_resume(struct platform_device *dev)
{
mutex_lock(&oprofile_perf_mutex);
if (oprofile_perf_enabled && op_perf_start())
oprofile_perf_enabled = 0;
mutex_unlock(&oprofile_perf_mutex);
return 0;
}
static struct platform_driver oprofile_driver = {
.driver = {
.name = "oprofile-perf",
},
.resume = oprofile_perf_resume,
.suspend = oprofile_perf_suspend,
};
static struct platform_device *oprofile_pdev;
static int __init init_driverfs(void)
{
int ret;
ret = platform_driver_register(&oprofile_driver);
if (ret)
return ret;
oprofile_pdev = platform_device_register_simple(
oprofile_driver.driver.name, 0, NULL, 0);
if (IS_ERR(oprofile_pdev)) {
ret = PTR_ERR(oprofile_pdev);
platform_driver_unregister(&oprofile_driver);
}
return ret;
}
static void exit_driverfs(void)
{
platform_device_unregister(oprofile_pdev);
platform_driver_unregister(&oprofile_driver);
}
#else
static inline int init_driverfs(void) { return 0; }
static inline void exit_driverfs(void) { }
#endif /* CONFIG_PM */
void oprofile_perf_exit(void)
{
int cpu, id;
struct perf_event *event;
for_each_possible_cpu(cpu) {
for (id = 0; id < num_counters; ++id) {
event = per_cpu(perf_events, cpu)[id];
if (event)
perf_event_release_kernel(event);
}
kfree(per_cpu(perf_events, cpu));
}
kfree(counter_config);
exit_driverfs();
}
int __init oprofile_perf_init(struct oprofile_operations *ops)
{
int cpu, ret = 0;
ret = init_driverfs();
if (ret)
return ret;
num_counters = perf_num_counters();
if (num_counters <= 0) {
pr_info("oprofile: no performance counters\n");
ret = -ENODEV;
goto out;
}
counter_config = kcalloc(num_counters,
sizeof(struct op_counter_config), GFP_KERNEL);
if (!counter_config) {
pr_info("oprofile: failed to allocate %d "
"counters\n", num_counters);
ret = -ENOMEM;
num_counters = 0;
goto out;
}
for_each_possible_cpu(cpu) {
per_cpu(perf_events, cpu) = kcalloc(num_counters,
sizeof(struct perf_event *), GFP_KERNEL);
if (!per_cpu(perf_events, cpu)) {
pr_info("oprofile: failed to allocate %d perf events "
"for cpu %d\n", num_counters, cpu);
ret = -ENOMEM;
goto out;
}
}
ops->create_files = oprofile_perf_create_files;
ops->setup = oprofile_perf_setup;
ops->start = oprofile_perf_start;
ops->stop = oprofile_perf_stop;
ops->shutdown = oprofile_perf_stop;
ops->cpu_type = op_name_from_perf_id();
if (!ops->cpu_type)
ret = -ENODEV;
else
pr_info("oprofile: using %s\n", ops->cpu_type);
out:
if (ret)
oprofile_perf_exit();
return ret;
}