oprofile: Abstract the perf-events backend
[linux-3.10.git] / drivers / oprofile / oprofile_perf.c
1 /*
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  */
13 struct 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
23 static int oprofile_perf_enabled;
24 static DEFINE_MUTEX(oprofile_perf_mutex);
25
26 static struct op_counter_config *counter_config;
27 static struct perf_event **perf_events[nr_cpumask_bits];
28 static int num_counters;
29
30 /*
31  * Overflow callback for oprofile.
32  */
33 static 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  */
55 static 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
72 static int op_create_counter(int cpu, int event)
73 {
74         int ret = 0;
75         struct perf_event *pevent;
76
77         if (!counter_config[event].enabled || (perf_events[cpu][event] != NULL))
78                 return ret;
79
80         pevent = perf_event_create_kernel_counter(&counter_config[event].attr,
81                                                   cpu, -1,
82                                                   op_overflow_handler);
83
84         if (IS_ERR(pevent)) {
85                 ret = PTR_ERR(pevent);
86         } else if (pevent->state != PERF_EVENT_STATE_ACTIVE) {
87                 pr_warning("oprofile: failed to enable event %d "
88                                 "on CPU %d\n", event, cpu);
89                 ret = -EBUSY;
90         } else {
91                 perf_events[cpu][event] = pevent;
92         }
93
94         return ret;
95 }
96
97 static void op_destroy_counter(int cpu, int event)
98 {
99         struct perf_event *pevent = perf_events[cpu][event];
100
101         if (pevent) {
102                 perf_event_release_kernel(pevent);
103                 perf_events[cpu][event] = NULL;
104         }
105 }
106
107 /*
108  * Called by oprofile_perf_start to create active perf events based on the
109  * perviously configured attributes.
110  */
111 static int op_perf_start(void)
112 {
113         int cpu, event, ret = 0;
114
115         for_each_online_cpu(cpu) {
116                 for (event = 0; event < num_counters; ++event) {
117                         ret = op_create_counter(cpu, event);
118                         if (ret)
119                                 goto out;
120                 }
121         }
122
123 out:
124         return ret;
125 }
126
127 /*
128  * Called by oprofile_perf_stop at the end of a profiling run.
129  */
130 static 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
139 static 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
160 static 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
168 static 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
182 static 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
192 static 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
201 static 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
210 static struct platform_driver oprofile_driver = {
211         .driver         = {
212                 .name           = "oprofile-perf",
213         },
214         .resume         = oprofile_perf_resume,
215         .suspend        = oprofile_perf_suspend,
216 };
217
218 static struct platform_device *oprofile_pdev;
219
220 static int __init init_driverfs(void)
221 {
222         int ret;
223
224         ret = platform_driver_register(&oprofile_driver);
225         if (ret)
226                 goto out;
227
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
235 out:
236         return ret;
237 }
238
239 static void __exit exit_driverfs(void)
240 {
241         platform_device_unregister(oprofile_pdev);
242         platform_driver_unregister(&oprofile_driver);
243 }
244 #else
245 static int __init init_driverfs(void) { return 0; }
246 #define exit_driverfs() do { } while (0)
247 #endif /* CONFIG_PM */
248
249 int __init oprofile_perf_init(struct oprofile_operations *ops)
250 {
251         int cpu, ret = 0;
252
253         memset(&perf_events, 0, sizeof(perf_events));
254
255         num_counters = perf_num_counters();
256         if (num_counters <= 0) {
257                 pr_info("oprofile: no performance counters\n");
258                 ret = -ENODEV;
259                 goto out;
260         }
261
262         counter_config = kcalloc(num_counters,
263                         sizeof(struct op_counter_config), GFP_KERNEL);
264
265         if (!counter_config) {
266                 pr_info("oprofile: failed to allocate %d "
267                                 "counters\n", num_counters);
268                 ret = -ENOMEM;
269                 goto out;
270         }
271
272         ret = init_driverfs();
273         if (ret)
274                 goto out;
275
276         for_each_possible_cpu(cpu) {
277                 perf_events[cpu] = kcalloc(num_counters,
278                                 sizeof(struct perf_event *), GFP_KERNEL);
279                 if (!perf_events[cpu]) {
280                         pr_info("oprofile: failed to allocate %d perf events "
281                                         "for cpu %d\n", num_counters, cpu);
282                         ret = -ENOMEM;
283                         goto out;
284                 }
285         }
286
287         ops->create_files       = oprofile_perf_create_files;
288         ops->setup              = oprofile_perf_setup;
289         ops->start              = oprofile_perf_start;
290         ops->stop               = oprofile_perf_stop;
291         ops->shutdown           = oprofile_perf_stop;
292         ops->cpu_type           = op_name_from_perf_id();
293
294         if (!ops->cpu_type)
295                 ret = -ENODEV;
296         else
297                 pr_info("oprofile: using %s\n", ops->cpu_type);
298
299 out:
300         if (ret) {
301                 for_each_possible_cpu(cpu)
302                         kfree(perf_events[cpu]);
303                 kfree(counter_config);
304         }
305
306         return ret;
307 }
308
309 void __exit oprofile_perf_exit(void)
310 {
311         int cpu, id;
312         struct perf_event *event;
313
314         for_each_possible_cpu(cpu) {
315                 for (id = 0; id < num_counters; ++id) {
316                         event = perf_events[cpu][id];
317                         if (event)
318                                 perf_event_release_kernel(event);
319                 }
320
321                 kfree(perf_events[cpu]);
322         }
323
324         kfree(counter_config);
325         exit_driverfs();
326 }