2 * Copyright 2010 ARM Ltd.
3 * Copyright 2012 Advanced Micro Devices, Inc., Robert Richter
5 * Perf-events backend for OProfile.
7 #include <linux/perf_event.h>
8 #include <linux/platform_device.h>
9 #include <linux/oprofile.h>
10 #include <linux/slab.h>
13 * Per performance monitor configuration as set via oprofilefs.
15 struct op_counter_config {
17 unsigned long enabled;
19 unsigned long unit_mask;
22 struct perf_event_attr attr;
25 static int oprofile_perf_enabled;
26 static DEFINE_MUTEX(oprofile_perf_mutex);
28 static struct op_counter_config *counter_config;
29 static DEFINE_PER_CPU(struct perf_event **, perf_events);
30 static int num_counters;
33 * Overflow callback for oprofile.
35 static void op_overflow_handler(struct perf_event *event,
36 struct perf_sample_data *data, struct pt_regs *regs)
39 u32 cpu = smp_processor_id();
41 for (id = 0; id < num_counters; ++id)
42 if (per_cpu(perf_events, cpu)[id] == event)
45 if (id != num_counters)
46 oprofile_add_sample(regs, id);
48 pr_warning("oprofile: ignoring spurious overflow "
53 * Called by oprofile_perf_setup to create perf attributes to mirror the oprofile
54 * settings in counter_config. Attributes are created as `pinned' events and
55 * so are permanently scheduled on the PMU.
57 static void op_perf_setup(void)
60 u32 size = sizeof(struct perf_event_attr);
61 struct perf_event_attr *attr;
63 for (i = 0; i < num_counters; ++i) {
64 attr = &counter_config[i].attr;
65 memset(attr, 0, size);
66 attr->type = PERF_TYPE_RAW;
68 attr->config = counter_config[i].event;
69 attr->sample_period = counter_config[i].count;
74 static int op_create_counter(int cpu, int event)
76 struct perf_event *pevent;
78 if (!counter_config[event].enabled || per_cpu(perf_events, cpu)[event])
81 pevent = perf_event_create_kernel_counter(&counter_config[event].attr,
83 op_overflow_handler, NULL);
86 return PTR_ERR(pevent);
88 if (pevent->state != PERF_EVENT_STATE_ACTIVE) {
89 perf_event_release_kernel(pevent);
90 pr_warning("oprofile: failed to enable event %d "
91 "on CPU %d\n", event, cpu);
95 per_cpu(perf_events, cpu)[event] = pevent;
100 static void op_destroy_counter(int cpu, int event)
102 struct perf_event *pevent = per_cpu(perf_events, cpu)[event];
105 perf_event_release_kernel(pevent);
106 per_cpu(perf_events, cpu)[event] = NULL;
111 * Called by oprofile_perf_start to create active perf events based on the
112 * perviously configured attributes.
114 static int op_perf_start(void)
116 int cpu, event, ret = 0;
118 for_each_online_cpu(cpu) {
119 for (event = 0; event < num_counters; ++event) {
120 ret = op_create_counter(cpu, event);
130 * Called by oprofile_perf_stop at the end of a profiling run.
132 static void op_perf_stop(void)
136 for_each_online_cpu(cpu)
137 for (event = 0; event < num_counters; ++event)
138 op_destroy_counter(cpu, event);
141 static int oprofile_perf_create_files(struct dentry *root)
145 for (i = 0; i < num_counters; i++) {
149 snprintf(buf, sizeof buf, "%d", i);
150 dir = oprofilefs_mkdir(root, buf);
151 oprofilefs_create_ulong(dir, "enabled", &counter_config[i].enabled);
152 oprofilefs_create_ulong(dir, "event", &counter_config[i].event);
153 oprofilefs_create_ulong(dir, "count", &counter_config[i].count);
154 oprofilefs_create_ulong(dir, "unit_mask", &counter_config[i].unit_mask);
155 oprofilefs_create_ulong(dir, "kernel", &counter_config[i].kernel);
156 oprofilefs_create_ulong(dir, "user", &counter_config[i].user);
162 static int oprofile_perf_setup(void)
164 raw_spin_lock(&oprofilefs_lock);
166 raw_spin_unlock(&oprofilefs_lock);
170 static int oprofile_perf_start(void)
174 mutex_lock(&oprofile_perf_mutex);
175 if (!oprofile_perf_enabled) {
178 oprofile_perf_enabled = 1;
180 mutex_unlock(&oprofile_perf_mutex);
184 static void oprofile_perf_stop(void)
186 mutex_lock(&oprofile_perf_mutex);
187 if (oprofile_perf_enabled)
189 oprofile_perf_enabled = 0;
190 mutex_unlock(&oprofile_perf_mutex);
195 static int oprofile_perf_suspend(struct platform_device *dev, pm_message_t state)
197 mutex_lock(&oprofile_perf_mutex);
198 if (oprofile_perf_enabled)
200 mutex_unlock(&oprofile_perf_mutex);
204 static int oprofile_perf_resume(struct platform_device *dev)
206 mutex_lock(&oprofile_perf_mutex);
207 if (oprofile_perf_enabled && op_perf_start())
208 oprofile_perf_enabled = 0;
209 mutex_unlock(&oprofile_perf_mutex);
213 static struct platform_driver oprofile_driver = {
215 .name = "oprofile-perf",
217 .resume = oprofile_perf_resume,
218 .suspend = oprofile_perf_suspend,
221 static struct platform_device *oprofile_pdev;
223 static int __init init_driverfs(void)
227 ret = platform_driver_register(&oprofile_driver);
231 oprofile_pdev = platform_device_register_simple(
232 oprofile_driver.driver.name, 0, NULL, 0);
233 if (IS_ERR(oprofile_pdev)) {
234 ret = PTR_ERR(oprofile_pdev);
235 platform_driver_unregister(&oprofile_driver);
241 static void exit_driverfs(void)
243 platform_device_unregister(oprofile_pdev);
244 platform_driver_unregister(&oprofile_driver);
249 static inline int init_driverfs(void) { return 0; }
250 static inline void exit_driverfs(void) { }
252 #endif /* CONFIG_PM */
254 void oprofile_perf_exit(void)
257 struct perf_event *event;
259 for_each_possible_cpu(cpu) {
260 for (id = 0; id < num_counters; ++id) {
261 event = per_cpu(perf_events, cpu)[id];
263 perf_event_release_kernel(event);
266 kfree(per_cpu(perf_events, cpu));
269 kfree(counter_config);
273 int __init oprofile_perf_init(struct oprofile_operations *ops)
277 ret = init_driverfs();
281 num_counters = perf_num_counters();
282 if (num_counters <= 0) {
283 pr_info("oprofile: no performance counters\n");
288 counter_config = kcalloc(num_counters,
289 sizeof(struct op_counter_config), GFP_KERNEL);
291 if (!counter_config) {
292 pr_info("oprofile: failed to allocate %d "
293 "counters\n", num_counters);
299 for_each_possible_cpu(cpu) {
300 per_cpu(perf_events, cpu) = kcalloc(num_counters,
301 sizeof(struct perf_event *), GFP_KERNEL);
302 if (!per_cpu(perf_events, cpu)) {
303 pr_info("oprofile: failed to allocate %d perf events "
304 "for cpu %d\n", num_counters, cpu);
310 ops->create_files = oprofile_perf_create_files;
311 ops->setup = oprofile_perf_setup;
312 ops->start = oprofile_perf_start;
313 ops->stop = oprofile_perf_stop;
314 ops->shutdown = oprofile_perf_stop;
315 ops->cpu_type = op_name_from_perf_id();
320 pr_info("oprofile: using %s\n", ops->cpu_type);
324 oprofile_perf_exit();