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3d90a007 MF |
1 | /* |
2 | * Copyright 2010 ARM Ltd. | |
3 | * | |
4 | * Perf-events backend for OProfile. | |
5 | */ | |
6 | #include <linux/perf_event.h> | |
277dd984 | 7 | #include <linux/platform_device.h> |
3d90a007 MF |
8 | #include <linux/oprofile.h> |
9 | #include <linux/slab.h> | |
10 | ||
11 | /* | |
12 | * Per performance monitor configuration as set via oprofilefs. | |
13 | */ | |
14 | struct op_counter_config { | |
15 | unsigned long count; | |
16 | unsigned long enabled; | |
17 | unsigned long event; | |
18 | unsigned long unit_mask; | |
19 | unsigned long kernel; | |
20 | unsigned long user; | |
21 | struct perf_event_attr attr; | |
22 | }; | |
23 | ||
24 | static int oprofile_perf_enabled; | |
25 | static DEFINE_MUTEX(oprofile_perf_mutex); | |
26 | ||
27 | static struct op_counter_config *counter_config; | |
e734568b | 28 | static struct perf_event **perf_events[NR_CPUS]; |
3d90a007 MF |
29 | static int num_counters; |
30 | ||
31 | /* | |
32 | * Overflow callback for oprofile. | |
33 | */ | |
7fcfd1ab | 34 | static void op_overflow_handler(struct perf_event *event, |
3d90a007 MF |
35 | struct perf_sample_data *data, struct pt_regs *regs) |
36 | { | |
37 | int id; | |
38 | u32 cpu = smp_processor_id(); | |
39 | ||
40 | for (id = 0; id < num_counters; ++id) | |
41 | if (perf_events[cpu][id] == event) | |
42 | break; | |
43 | ||
44 | if (id != num_counters) | |
45 | oprofile_add_sample(regs, id); | |
46 | else | |
47 | pr_warning("oprofile: ignoring spurious overflow " | |
48 | "on cpu %u\n", cpu); | |
49 | } | |
50 | ||
51 | /* | |
52 | * Called by oprofile_perf_setup to create perf attributes to mirror the oprofile | |
53 | * settings in counter_config. Attributes are created as `pinned' events and | |
54 | * so are permanently scheduled on the PMU. | |
55 | */ | |
56 | static void op_perf_setup(void) | |
57 | { | |
58 | int i; | |
59 | u32 size = sizeof(struct perf_event_attr); | |
60 | struct perf_event_attr *attr; | |
61 | ||
62 | for (i = 0; i < num_counters; ++i) { | |
63 | attr = &counter_config[i].attr; | |
64 | memset(attr, 0, size); | |
65 | attr->type = PERF_TYPE_RAW; | |
66 | attr->size = size; | |
67 | attr->config = counter_config[i].event; | |
68 | attr->sample_period = counter_config[i].count; | |
69 | attr->pinned = 1; | |
70 | } | |
71 | } | |
72 | ||
73 | static int op_create_counter(int cpu, int event) | |
74 | { | |
3d90a007 MF |
75 | struct perf_event *pevent; |
76 | ||
2bcb2b64 RR |
77 | if (!counter_config[event].enabled || perf_events[cpu][event]) |
78 | return 0; | |
3d90a007 MF |
79 | |
80 | pevent = perf_event_create_kernel_counter(&counter_config[event].attr, | |
6268464b | 81 | cpu, NULL, |
4dc0da86 | 82 | op_overflow_handler, NULL); |
3d90a007 | 83 | |
2bcb2b64 RR |
84 | if (IS_ERR(pevent)) |
85 | return PTR_ERR(pevent); | |
86 | ||
87 | if (pevent->state != PERF_EVENT_STATE_ACTIVE) { | |
81771974 | 88 | perf_event_release_kernel(pevent); |
3d90a007 MF |
89 | pr_warning("oprofile: failed to enable event %d " |
90 | "on CPU %d\n", event, cpu); | |
2bcb2b64 | 91 | return -EBUSY; |
3d90a007 MF |
92 | } |
93 | ||
2bcb2b64 RR |
94 | perf_events[cpu][event] = pevent; |
95 | ||
96 | return 0; | |
3d90a007 MF |
97 | } |
98 | ||
99 | static void op_destroy_counter(int cpu, int event) | |
100 | { | |
101 | struct perf_event *pevent = perf_events[cpu][event]; | |
102 | ||
103 | if (pevent) { | |
104 | perf_event_release_kernel(pevent); | |
105 | perf_events[cpu][event] = NULL; | |
106 | } | |
107 | } | |
108 | ||
109 | /* | |
110 | * Called by oprofile_perf_start to create active perf events based on the | |
111 | * perviously configured attributes. | |
112 | */ | |
113 | static int op_perf_start(void) | |
114 | { | |
115 | int cpu, event, ret = 0; | |
116 | ||
117 | for_each_online_cpu(cpu) { | |
118 | for (event = 0; event < num_counters; ++event) { | |
119 | ret = op_create_counter(cpu, event); | |
120 | if (ret) | |
9c91283a | 121 | return ret; |
3d90a007 MF |
122 | } |
123 | } | |
124 | ||
3d90a007 MF |
125 | return ret; |
126 | } | |
127 | ||
128 | /* | |
129 | * Called by oprofile_perf_stop at the end of a profiling run. | |
130 | */ | |
131 | static void op_perf_stop(void) | |
132 | { | |
133 | int cpu, event; | |
134 | ||
135 | for_each_online_cpu(cpu) | |
136 | for (event = 0; event < num_counters; ++event) | |
137 | op_destroy_counter(cpu, event); | |
138 | } | |
139 | ||
140 | static int oprofile_perf_create_files(struct super_block *sb, struct dentry *root) | |
141 | { | |
142 | unsigned int i; | |
143 | ||
144 | for (i = 0; i < num_counters; i++) { | |
145 | struct dentry *dir; | |
146 | char buf[4]; | |
147 | ||
148 | snprintf(buf, sizeof buf, "%d", i); | |
149 | dir = oprofilefs_mkdir(sb, root, buf); | |
150 | oprofilefs_create_ulong(sb, dir, "enabled", &counter_config[i].enabled); | |
151 | oprofilefs_create_ulong(sb, dir, "event", &counter_config[i].event); | |
152 | oprofilefs_create_ulong(sb, dir, "count", &counter_config[i].count); | |
153 | oprofilefs_create_ulong(sb, dir, "unit_mask", &counter_config[i].unit_mask); | |
154 | oprofilefs_create_ulong(sb, dir, "kernel", &counter_config[i].kernel); | |
155 | oprofilefs_create_ulong(sb, dir, "user", &counter_config[i].user); | |
156 | } | |
157 | ||
158 | return 0; | |
159 | } | |
160 | ||
161 | static int oprofile_perf_setup(void) | |
162 | { | |
2d21a29f | 163 | raw_spin_lock(&oprofilefs_lock); |
3d90a007 | 164 | op_perf_setup(); |
2d21a29f | 165 | raw_spin_unlock(&oprofilefs_lock); |
3d90a007 MF |
166 | return 0; |
167 | } | |
168 | ||
169 | static int oprofile_perf_start(void) | |
170 | { | |
171 | int ret = -EBUSY; | |
172 | ||
173 | mutex_lock(&oprofile_perf_mutex); | |
174 | if (!oprofile_perf_enabled) { | |
175 | ret = 0; | |
176 | op_perf_start(); | |
177 | oprofile_perf_enabled = 1; | |
178 | } | |
179 | mutex_unlock(&oprofile_perf_mutex); | |
180 | return ret; | |
181 | } | |
182 | ||
183 | static void oprofile_perf_stop(void) | |
184 | { | |
185 | mutex_lock(&oprofile_perf_mutex); | |
186 | if (oprofile_perf_enabled) | |
187 | op_perf_stop(); | |
188 | oprofile_perf_enabled = 0; | |
189 | mutex_unlock(&oprofile_perf_mutex); | |
190 | } | |
191 | ||
192 | #ifdef CONFIG_PM | |
cd254f29 | 193 | |
3d90a007 MF |
194 | static int oprofile_perf_suspend(struct platform_device *dev, pm_message_t state) |
195 | { | |
196 | mutex_lock(&oprofile_perf_mutex); | |
197 | if (oprofile_perf_enabled) | |
198 | op_perf_stop(); | |
199 | mutex_unlock(&oprofile_perf_mutex); | |
200 | return 0; | |
201 | } | |
202 | ||
203 | static int oprofile_perf_resume(struct platform_device *dev) | |
204 | { | |
205 | mutex_lock(&oprofile_perf_mutex); | |
206 | if (oprofile_perf_enabled && op_perf_start()) | |
207 | oprofile_perf_enabled = 0; | |
208 | mutex_unlock(&oprofile_perf_mutex); | |
209 | return 0; | |
210 | } | |
211 | ||
212 | static struct platform_driver oprofile_driver = { | |
213 | .driver = { | |
214 | .name = "oprofile-perf", | |
215 | }, | |
216 | .resume = oprofile_perf_resume, | |
217 | .suspend = oprofile_perf_suspend, | |
218 | }; | |
219 | ||
220 | static struct platform_device *oprofile_pdev; | |
221 | ||
222 | static int __init init_driverfs(void) | |
223 | { | |
224 | int ret; | |
225 | ||
226 | ret = platform_driver_register(&oprofile_driver); | |
227 | if (ret) | |
9c91283a | 228 | return ret; |
3d90a007 MF |
229 | |
230 | oprofile_pdev = platform_device_register_simple( | |
231 | oprofile_driver.driver.name, 0, NULL, 0); | |
232 | if (IS_ERR(oprofile_pdev)) { | |
233 | ret = PTR_ERR(oprofile_pdev); | |
234 | platform_driver_unregister(&oprofile_driver); | |
235 | } | |
236 | ||
3d90a007 MF |
237 | return ret; |
238 | } | |
239 | ||
b3b3a9b6 | 240 | static void exit_driverfs(void) |
3d90a007 MF |
241 | { |
242 | platform_device_unregister(oprofile_pdev); | |
243 | platform_driver_unregister(&oprofile_driver); | |
244 | } | |
cd254f29 | 245 | |
3d90a007 | 246 | #else |
cd254f29 RR |
247 | |
248 | static inline int init_driverfs(void) { return 0; } | |
249 | static inline void exit_driverfs(void) { } | |
250 | ||
3d90a007 MF |
251 | #endif /* CONFIG_PM */ |
252 | ||
e9677b3c RR |
253 | void oprofile_perf_exit(void) |
254 | { | |
255 | int cpu, id; | |
256 | struct perf_event *event; | |
257 | ||
258 | for_each_possible_cpu(cpu) { | |
259 | for (id = 0; id < num_counters; ++id) { | |
260 | event = perf_events[cpu][id]; | |
261 | if (event) | |
262 | perf_event_release_kernel(event); | |
263 | } | |
264 | ||
265 | kfree(perf_events[cpu]); | |
266 | } | |
267 | ||
268 | kfree(counter_config); | |
269 | exit_driverfs(); | |
270 | } | |
271 | ||
3d90a007 MF |
272 | int __init oprofile_perf_init(struct oprofile_operations *ops) |
273 | { | |
274 | int cpu, ret = 0; | |
275 | ||
e9677b3c RR |
276 | ret = init_driverfs(); |
277 | if (ret) | |
278 | return ret; | |
279 | ||
3d90a007 MF |
280 | memset(&perf_events, 0, sizeof(perf_events)); |
281 | ||
282 | num_counters = perf_num_counters(); | |
283 | if (num_counters <= 0) { | |
284 | pr_info("oprofile: no performance counters\n"); | |
285 | ret = -ENODEV; | |
286 | goto out; | |
287 | } | |
288 | ||
289 | counter_config = kcalloc(num_counters, | |
290 | sizeof(struct op_counter_config), GFP_KERNEL); | |
291 | ||
292 | if (!counter_config) { | |
293 | pr_info("oprofile: failed to allocate %d " | |
294 | "counters\n", num_counters); | |
295 | ret = -ENOMEM; | |
e9677b3c | 296 | num_counters = 0; |
3d90a007 MF |
297 | goto out; |
298 | } | |
299 | ||
3d90a007 MF |
300 | for_each_possible_cpu(cpu) { |
301 | perf_events[cpu] = kcalloc(num_counters, | |
302 | sizeof(struct perf_event *), GFP_KERNEL); | |
303 | if (!perf_events[cpu]) { | |
304 | pr_info("oprofile: failed to allocate %d perf events " | |
305 | "for cpu %d\n", num_counters, cpu); | |
306 | ret = -ENOMEM; | |
307 | goto out; | |
308 | } | |
309 | } | |
310 | ||
311 | ops->create_files = oprofile_perf_create_files; | |
312 | ops->setup = oprofile_perf_setup; | |
313 | ops->start = oprofile_perf_start; | |
314 | ops->stop = oprofile_perf_stop; | |
315 | ops->shutdown = oprofile_perf_stop; | |
316 | ops->cpu_type = op_name_from_perf_id(); | |
317 | ||
318 | if (!ops->cpu_type) | |
319 | ret = -ENODEV; | |
320 | else | |
321 | pr_info("oprofile: using %s\n", ops->cpu_type); | |
322 | ||
323 | out: | |
e9677b3c RR |
324 | if (ret) |
325 | oprofile_perf_exit(); | |
3d90a007 MF |
326 | |
327 | return ret; | |
328 | } |