blob: a34137f2e26c1d40985c2f4bb14de27eea5ab761 [file] [log] [blame]
Matt Fleming3d90a002010-09-27 20:45:08 +01001/*
2 * Copyright 2010 ARM Ltd.
3 *
4 * Perf-events backend for OProfile.
5 */
6#include <linux/perf_event.h>
7#include <linux/oprofile.h>
8#include <linux/slab.h>
9
10/*
11 * Per performance monitor configuration as set via oprofilefs.
12 */
13struct op_counter_config {
14 unsigned long count;
15 unsigned long enabled;
16 unsigned long event;
17 unsigned long unit_mask;
18 unsigned long kernel;
19 unsigned long user;
20 struct perf_event_attr attr;
21};
22
23static int oprofile_perf_enabled;
24static DEFINE_MUTEX(oprofile_perf_mutex);
25
26static struct op_counter_config *counter_config;
27static struct perf_event **perf_events[nr_cpumask_bits];
28static int num_counters;
29
30/*
31 * Overflow callback for oprofile.
32 */
33static void op_overflow_handler(struct perf_event *event, int unused,
34 struct perf_sample_data *data, struct pt_regs *regs)
35{
36 int id;
37 u32 cpu = smp_processor_id();
38
39 for (id = 0; id < num_counters; ++id)
40 if (perf_events[cpu][id] == event)
41 break;
42
43 if (id != num_counters)
44 oprofile_add_sample(regs, id);
45 else
46 pr_warning("oprofile: ignoring spurious overflow "
47 "on cpu %u\n", cpu);
48}
49
50/*
51 * Called by oprofile_perf_setup to create perf attributes to mirror the oprofile
52 * settings in counter_config. Attributes are created as `pinned' events and
53 * so are permanently scheduled on the PMU.
54 */
55static void op_perf_setup(void)
56{
57 int i;
58 u32 size = sizeof(struct perf_event_attr);
59 struct perf_event_attr *attr;
60
61 for (i = 0; i < num_counters; ++i) {
62 attr = &counter_config[i].attr;
63 memset(attr, 0, size);
64 attr->type = PERF_TYPE_RAW;
65 attr->size = size;
66 attr->config = counter_config[i].event;
67 attr->sample_period = counter_config[i].count;
68 attr->pinned = 1;
69 }
70}
71
72static int op_create_counter(int cpu, int event)
73{
Matt Fleming3d90a002010-09-27 20:45:08 +010074 struct perf_event *pevent;
75
Robert Richter2bcb2b62010-09-29 14:43:29 +020076 if (!counter_config[event].enabled || perf_events[cpu][event])
77 return 0;
Matt Fleming3d90a002010-09-27 20:45:08 +010078
79 pevent = perf_event_create_kernel_counter(&counter_config[event].attr,
80 cpu, -1,
81 op_overflow_handler);
82
Robert Richter2bcb2b62010-09-29 14:43:29 +020083 if (IS_ERR(pevent))
84 return PTR_ERR(pevent);
85
86 if (pevent->state != PERF_EVENT_STATE_ACTIVE) {
Robert Richter81771972010-09-29 16:52:25 +020087 perf_event_release_kernel(pevent);
Matt Fleming3d90a002010-09-27 20:45:08 +010088 pr_warning("oprofile: failed to enable event %d "
89 "on CPU %d\n", event, cpu);
Robert Richter2bcb2b62010-09-29 14:43:29 +020090 return -EBUSY;
Matt Fleming3d90a002010-09-27 20:45:08 +010091 }
92
Robert Richter2bcb2b62010-09-29 14:43:29 +020093 perf_events[cpu][event] = pevent;
94
95 return 0;
Matt Fleming3d90a002010-09-27 20:45:08 +010096}
97
98static void op_destroy_counter(int cpu, int event)
99{
100 struct perf_event *pevent = perf_events[cpu][event];
101
102 if (pevent) {
103 perf_event_release_kernel(pevent);
104 perf_events[cpu][event] = NULL;
105 }
106}
107
108/*
109 * Called by oprofile_perf_start to create active perf events based on the
110 * perviously configured attributes.
111 */
112static int op_perf_start(void)
113{
114 int cpu, event, ret = 0;
115
116 for_each_online_cpu(cpu) {
117 for (event = 0; event < num_counters; ++event) {
118 ret = op_create_counter(cpu, event);
119 if (ret)
Robert Richter9c912832010-08-27 14:32:41 +0200120 return ret;
Matt Fleming3d90a002010-09-27 20:45:08 +0100121 }
122 }
123
Matt Fleming3d90a002010-09-27 20:45:08 +0100124 return ret;
125}
126
127/*
128 * Called by oprofile_perf_stop at the end of a profiling run.
129 */
130static void op_perf_stop(void)
131{
132 int cpu, event;
133
134 for_each_online_cpu(cpu)
135 for (event = 0; event < num_counters; ++event)
136 op_destroy_counter(cpu, event);
137}
138
139static int oprofile_perf_create_files(struct super_block *sb, struct dentry *root)
140{
141 unsigned int i;
142
143 for (i = 0; i < num_counters; i++) {
144 struct dentry *dir;
145 char buf[4];
146
147 snprintf(buf, sizeof buf, "%d", i);
148 dir = oprofilefs_mkdir(sb, root, buf);
149 oprofilefs_create_ulong(sb, dir, "enabled", &counter_config[i].enabled);
150 oprofilefs_create_ulong(sb, dir, "event", &counter_config[i].event);
151 oprofilefs_create_ulong(sb, dir, "count", &counter_config[i].count);
152 oprofilefs_create_ulong(sb, dir, "unit_mask", &counter_config[i].unit_mask);
153 oprofilefs_create_ulong(sb, dir, "kernel", &counter_config[i].kernel);
154 oprofilefs_create_ulong(sb, dir, "user", &counter_config[i].user);
155 }
156
157 return 0;
158}
159
160static int oprofile_perf_setup(void)
161{
162 spin_lock(&oprofilefs_lock);
163 op_perf_setup();
164 spin_unlock(&oprofilefs_lock);
165 return 0;
166}
167
168static int oprofile_perf_start(void)
169{
170 int ret = -EBUSY;
171
172 mutex_lock(&oprofile_perf_mutex);
173 if (!oprofile_perf_enabled) {
174 ret = 0;
175 op_perf_start();
176 oprofile_perf_enabled = 1;
177 }
178 mutex_unlock(&oprofile_perf_mutex);
179 return ret;
180}
181
182static void oprofile_perf_stop(void)
183{
184 mutex_lock(&oprofile_perf_mutex);
185 if (oprofile_perf_enabled)
186 op_perf_stop();
187 oprofile_perf_enabled = 0;
188 mutex_unlock(&oprofile_perf_mutex);
189}
190
191#ifdef CONFIG_PM
192static int oprofile_perf_suspend(struct platform_device *dev, pm_message_t state)
193{
194 mutex_lock(&oprofile_perf_mutex);
195 if (oprofile_perf_enabled)
196 op_perf_stop();
197 mutex_unlock(&oprofile_perf_mutex);
198 return 0;
199}
200
201static int oprofile_perf_resume(struct platform_device *dev)
202{
203 mutex_lock(&oprofile_perf_mutex);
204 if (oprofile_perf_enabled && op_perf_start())
205 oprofile_perf_enabled = 0;
206 mutex_unlock(&oprofile_perf_mutex);
207 return 0;
208}
209
210static struct platform_driver oprofile_driver = {
211 .driver = {
212 .name = "oprofile-perf",
213 },
214 .resume = oprofile_perf_resume,
215 .suspend = oprofile_perf_suspend,
216};
217
218static struct platform_device *oprofile_pdev;
219
220static int __init init_driverfs(void)
221{
222 int ret;
223
224 ret = platform_driver_register(&oprofile_driver);
225 if (ret)
Robert Richter9c912832010-08-27 14:32:41 +0200226 return ret;
Matt Fleming3d90a002010-09-27 20:45:08 +0100227
228 oprofile_pdev = platform_device_register_simple(
229 oprofile_driver.driver.name, 0, NULL, 0);
230 if (IS_ERR(oprofile_pdev)) {
231 ret = PTR_ERR(oprofile_pdev);
232 platform_driver_unregister(&oprofile_driver);
233 }
234
Matt Fleming3d90a002010-09-27 20:45:08 +0100235 return ret;
236}
237
238static void __exit exit_driverfs(void)
239{
240 platform_device_unregister(oprofile_pdev);
241 platform_driver_unregister(&oprofile_driver);
242}
243#else
244static int __init init_driverfs(void) { return 0; }
245#define exit_driverfs() do { } while (0)
246#endif /* CONFIG_PM */
247
248int __init oprofile_perf_init(struct oprofile_operations *ops)
249{
250 int cpu, ret = 0;
251
252 memset(&perf_events, 0, sizeof(perf_events));
253
254 num_counters = perf_num_counters();
255 if (num_counters <= 0) {
256 pr_info("oprofile: no performance counters\n");
257 ret = -ENODEV;
258 goto out;
259 }
260
261 counter_config = kcalloc(num_counters,
262 sizeof(struct op_counter_config), GFP_KERNEL);
263
264 if (!counter_config) {
265 pr_info("oprofile: failed to allocate %d "
266 "counters\n", num_counters);
267 ret = -ENOMEM;
268 goto out;
269 }
270
271 ret = init_driverfs();
272 if (ret)
273 goto out;
274
275 for_each_possible_cpu(cpu) {
276 perf_events[cpu] = kcalloc(num_counters,
277 sizeof(struct perf_event *), GFP_KERNEL);
278 if (!perf_events[cpu]) {
279 pr_info("oprofile: failed to allocate %d perf events "
280 "for cpu %d\n", num_counters, cpu);
281 ret = -ENOMEM;
282 goto out;
283 }
284 }
285
286 ops->create_files = oprofile_perf_create_files;
287 ops->setup = oprofile_perf_setup;
288 ops->start = oprofile_perf_start;
289 ops->stop = oprofile_perf_stop;
290 ops->shutdown = oprofile_perf_stop;
291 ops->cpu_type = op_name_from_perf_id();
292
293 if (!ops->cpu_type)
294 ret = -ENODEV;
295 else
296 pr_info("oprofile: using %s\n", ops->cpu_type);
297
298out:
299 if (ret) {
300 for_each_possible_cpu(cpu)
301 kfree(perf_events[cpu]);
302 kfree(counter_config);
303 }
304
305 return ret;
306}
307
308void __exit oprofile_perf_exit(void)
309{
310 int cpu, id;
311 struct perf_event *event;
312
313 for_each_possible_cpu(cpu) {
314 for (id = 0; id < num_counters; ++id) {
315 event = perf_events[cpu][id];
316 if (event)
317 perf_event_release_kernel(event);
318 }
319
320 kfree(perf_events[cpu]);
321 }
322
323 kfree(counter_config);
324 exit_driverfs();
325}