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