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Commit | Line | Data |
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b77e38aa SR |
1 | /* |
2 | * event tracer | |
3 | * | |
4 | * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com> | |
5 | * | |
6 | */ | |
7 | ||
8 | #include <linux/debugfs.h> | |
9 | #include <linux/uaccess.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/ctype.h> | |
12 | ||
c32e827b | 13 | #include "trace.h" |
b77e38aa | 14 | |
b628b3e6 SR |
15 | #define TRACE_SYSTEM "TRACE_SYSTEM" |
16 | ||
1473e441 SR |
17 | #define events_for_each(event) \ |
18 | for (event = __start_ftrace_events; \ | |
19 | (unsigned long)event < (unsigned long)__stop_ftrace_events; \ | |
20 | event++) | |
21 | ||
b77e38aa SR |
22 | void event_trace_printk(unsigned long ip, const char *fmt, ...) |
23 | { | |
24 | va_list ap; | |
25 | ||
26 | va_start(ap, fmt); | |
27 | tracing_record_cmdline(current); | |
28 | trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap); | |
29 | va_end(ap); | |
30 | } | |
31 | ||
32 | static void ftrace_clear_events(void) | |
33 | { | |
34 | struct ftrace_event_call *call = (void *)__start_ftrace_events; | |
35 | ||
36 | ||
37 | while ((unsigned long)call < (unsigned long)__stop_ftrace_events) { | |
38 | ||
39 | if (call->enabled) { | |
40 | call->enabled = 0; | |
41 | call->unregfunc(); | |
42 | } | |
43 | call++; | |
44 | } | |
45 | } | |
46 | ||
47 | static int ftrace_set_clr_event(char *buf, int set) | |
48 | { | |
1473e441 | 49 | struct ftrace_event_call *call = __start_ftrace_events; |
b628b3e6 SR |
50 | char *event = NULL, *sub = NULL, *match; |
51 | int ret = -EINVAL; | |
52 | ||
53 | /* | |
54 | * The buf format can be <subsystem>:<event-name> | |
55 | * *:<event-name> means any event by that name. | |
56 | * :<event-name> is the same. | |
57 | * | |
58 | * <subsystem>:* means all events in that subsystem | |
59 | * <subsystem>: means the same. | |
60 | * | |
61 | * <name> (no ':') means all events in a subsystem with | |
62 | * the name <name> or any event that matches <name> | |
63 | */ | |
64 | ||
65 | match = strsep(&buf, ":"); | |
66 | if (buf) { | |
67 | sub = match; | |
68 | event = buf; | |
69 | match = NULL; | |
70 | ||
71 | if (!strlen(sub) || strcmp(sub, "*") == 0) | |
72 | sub = NULL; | |
73 | if (!strlen(event) || strcmp(event, "*") == 0) | |
74 | event = NULL; | |
75 | } | |
b77e38aa | 76 | |
1473e441 | 77 | events_for_each(call) { |
b77e38aa | 78 | |
1473e441 SR |
79 | if (!call->name) |
80 | continue; | |
81 | ||
b628b3e6 SR |
82 | if (match && |
83 | strcmp(match, call->name) != 0 && | |
84 | strcmp(match, call->system) != 0) | |
85 | continue; | |
86 | ||
87 | if (sub && strcmp(sub, call->system) != 0) | |
88 | continue; | |
89 | ||
90 | if (event && strcmp(event, call->name) != 0) | |
b77e38aa | 91 | continue; |
b77e38aa SR |
92 | |
93 | if (set) { | |
94 | /* Already set? */ | |
95 | if (call->enabled) | |
96 | return 0; | |
97 | call->enabled = 1; | |
98 | call->regfunc(); | |
99 | } else { | |
100 | /* Already cleared? */ | |
101 | if (!call->enabled) | |
102 | return 0; | |
103 | call->enabled = 0; | |
104 | call->unregfunc(); | |
105 | } | |
b628b3e6 | 106 | ret = 0; |
b77e38aa | 107 | } |
b628b3e6 | 108 | return ret; |
b77e38aa SR |
109 | } |
110 | ||
111 | /* 128 should be much more than enough */ | |
112 | #define EVENT_BUF_SIZE 127 | |
113 | ||
114 | static ssize_t | |
115 | ftrace_event_write(struct file *file, const char __user *ubuf, | |
116 | size_t cnt, loff_t *ppos) | |
117 | { | |
118 | size_t read = 0; | |
119 | int i, set = 1; | |
120 | ssize_t ret; | |
121 | char *buf; | |
122 | char ch; | |
123 | ||
124 | if (!cnt || cnt < 0) | |
125 | return 0; | |
126 | ||
127 | ret = get_user(ch, ubuf++); | |
128 | if (ret) | |
129 | return ret; | |
130 | read++; | |
131 | cnt--; | |
132 | ||
133 | /* skip white space */ | |
134 | while (cnt && isspace(ch)) { | |
135 | ret = get_user(ch, ubuf++); | |
136 | if (ret) | |
137 | return ret; | |
138 | read++; | |
139 | cnt--; | |
140 | } | |
141 | ||
142 | /* Only white space found? */ | |
143 | if (isspace(ch)) { | |
144 | file->f_pos += read; | |
145 | ret = read; | |
146 | return ret; | |
147 | } | |
148 | ||
149 | buf = kmalloc(EVENT_BUF_SIZE+1, GFP_KERNEL); | |
150 | if (!buf) | |
151 | return -ENOMEM; | |
152 | ||
153 | if (cnt > EVENT_BUF_SIZE) | |
154 | cnt = EVENT_BUF_SIZE; | |
155 | ||
156 | i = 0; | |
157 | while (cnt && !isspace(ch)) { | |
158 | if (!i && ch == '!') | |
159 | set = 0; | |
160 | else | |
161 | buf[i++] = ch; | |
162 | ||
163 | ret = get_user(ch, ubuf++); | |
164 | if (ret) | |
165 | goto out_free; | |
166 | read++; | |
167 | cnt--; | |
168 | } | |
169 | buf[i] = 0; | |
170 | ||
171 | file->f_pos += read; | |
172 | ||
173 | ret = ftrace_set_clr_event(buf, set); | |
174 | if (ret) | |
175 | goto out_free; | |
176 | ||
177 | ret = read; | |
178 | ||
179 | out_free: | |
180 | kfree(buf); | |
181 | ||
182 | return ret; | |
183 | } | |
184 | ||
185 | static void * | |
186 | t_next(struct seq_file *m, void *v, loff_t *pos) | |
187 | { | |
188 | struct ftrace_event_call *call = m->private; | |
189 | struct ftrace_event_call *next = call; | |
190 | ||
191 | (*pos)++; | |
192 | ||
193 | if ((unsigned long)call >= (unsigned long)__stop_ftrace_events) | |
194 | return NULL; | |
195 | ||
196 | m->private = ++next; | |
197 | ||
198 | return call; | |
199 | } | |
200 | ||
201 | static void *t_start(struct seq_file *m, loff_t *pos) | |
202 | { | |
203 | return t_next(m, NULL, pos); | |
204 | } | |
205 | ||
206 | static void * | |
207 | s_next(struct seq_file *m, void *v, loff_t *pos) | |
208 | { | |
209 | struct ftrace_event_call *call = m->private; | |
210 | struct ftrace_event_call *next; | |
211 | ||
212 | (*pos)++; | |
213 | ||
214 | retry: | |
215 | if ((unsigned long)call >= (unsigned long)__stop_ftrace_events) | |
216 | return NULL; | |
217 | ||
218 | if (!call->enabled) { | |
219 | call++; | |
220 | goto retry; | |
221 | } | |
222 | ||
223 | next = call; | |
224 | m->private = ++next; | |
225 | ||
226 | return call; | |
227 | } | |
228 | ||
229 | static void *s_start(struct seq_file *m, loff_t *pos) | |
230 | { | |
231 | return s_next(m, NULL, pos); | |
232 | } | |
233 | ||
234 | static int t_show(struct seq_file *m, void *v) | |
235 | { | |
236 | struct ftrace_event_call *call = v; | |
237 | ||
b628b3e6 SR |
238 | if (strcmp(call->system, TRACE_SYSTEM) != 0) |
239 | seq_printf(m, "%s:", call->system); | |
b77e38aa SR |
240 | seq_printf(m, "%s\n", call->name); |
241 | ||
242 | return 0; | |
243 | } | |
244 | ||
245 | static void t_stop(struct seq_file *m, void *p) | |
246 | { | |
247 | } | |
248 | ||
249 | static int | |
250 | ftrace_event_seq_open(struct inode *inode, struct file *file) | |
251 | { | |
252 | int ret; | |
253 | const struct seq_operations *seq_ops; | |
254 | ||
255 | if ((file->f_mode & FMODE_WRITE) && | |
256 | !(file->f_flags & O_APPEND)) | |
257 | ftrace_clear_events(); | |
258 | ||
259 | seq_ops = inode->i_private; | |
260 | ret = seq_open(file, seq_ops); | |
261 | if (!ret) { | |
262 | struct seq_file *m = file->private_data; | |
263 | ||
264 | m->private = __start_ftrace_events; | |
265 | } | |
266 | return ret; | |
267 | } | |
268 | ||
1473e441 SR |
269 | static ssize_t |
270 | event_enable_read(struct file *filp, char __user *ubuf, size_t cnt, | |
271 | loff_t *ppos) | |
272 | { | |
273 | struct ftrace_event_call *call = filp->private_data; | |
274 | char *buf; | |
275 | ||
276 | if (call->enabled) | |
277 | buf = "1\n"; | |
278 | else | |
279 | buf = "0\n"; | |
280 | ||
281 | return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2); | |
282 | } | |
283 | ||
284 | static ssize_t | |
285 | event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt, | |
286 | loff_t *ppos) | |
287 | { | |
288 | struct ftrace_event_call *call = filp->private_data; | |
289 | char buf[64]; | |
290 | unsigned long val; | |
291 | int ret; | |
292 | ||
293 | if (cnt >= sizeof(buf)) | |
294 | return -EINVAL; | |
295 | ||
296 | if (copy_from_user(&buf, ubuf, cnt)) | |
297 | return -EFAULT; | |
298 | ||
299 | buf[cnt] = 0; | |
300 | ||
301 | ret = strict_strtoul(buf, 10, &val); | |
302 | if (ret < 0) | |
303 | return ret; | |
304 | ||
305 | switch (val) { | |
306 | case 0: | |
307 | if (!call->enabled) | |
308 | break; | |
309 | ||
310 | call->enabled = 0; | |
311 | call->unregfunc(); | |
312 | break; | |
313 | case 1: | |
314 | if (call->enabled) | |
315 | break; | |
316 | ||
317 | call->enabled = 1; | |
318 | call->regfunc(); | |
319 | break; | |
320 | ||
321 | default: | |
322 | return -EINVAL; | |
323 | } | |
324 | ||
325 | *ppos += cnt; | |
326 | ||
327 | return cnt; | |
328 | } | |
329 | ||
b77e38aa SR |
330 | static const struct seq_operations show_event_seq_ops = { |
331 | .start = t_start, | |
332 | .next = t_next, | |
333 | .show = t_show, | |
334 | .stop = t_stop, | |
335 | }; | |
336 | ||
337 | static const struct seq_operations show_set_event_seq_ops = { | |
338 | .start = s_start, | |
339 | .next = s_next, | |
340 | .show = t_show, | |
341 | .stop = t_stop, | |
342 | }; | |
343 | ||
344 | static const struct file_operations ftrace_avail_fops = { | |
345 | .open = ftrace_event_seq_open, | |
346 | .read = seq_read, | |
347 | .llseek = seq_lseek, | |
348 | .release = seq_release, | |
349 | }; | |
350 | ||
351 | static const struct file_operations ftrace_set_event_fops = { | |
352 | .open = ftrace_event_seq_open, | |
353 | .read = seq_read, | |
354 | .write = ftrace_event_write, | |
355 | .llseek = seq_lseek, | |
356 | .release = seq_release, | |
357 | }; | |
358 | ||
1473e441 SR |
359 | static const struct file_operations ftrace_enable_fops = { |
360 | .open = tracing_open_generic, | |
361 | .read = event_enable_read, | |
362 | .write = event_enable_write, | |
363 | }; | |
364 | ||
365 | static struct dentry *event_trace_events_dir(void) | |
366 | { | |
367 | static struct dentry *d_tracer; | |
368 | static struct dentry *d_events; | |
369 | ||
370 | if (d_events) | |
371 | return d_events; | |
372 | ||
373 | d_tracer = tracing_init_dentry(); | |
374 | if (!d_tracer) | |
375 | return NULL; | |
376 | ||
377 | d_events = debugfs_create_dir("events", d_tracer); | |
378 | if (!d_events) | |
379 | pr_warning("Could not create debugfs " | |
380 | "'events' directory\n"); | |
381 | ||
382 | return d_events; | |
383 | } | |
384 | ||
6ecc2d1c SR |
385 | struct event_subsystem { |
386 | struct list_head list; | |
387 | const char *name; | |
388 | struct dentry *entry; | |
389 | }; | |
390 | ||
391 | static LIST_HEAD(event_subsystems); | |
392 | ||
393 | static struct dentry * | |
394 | event_subsystem_dir(const char *name, struct dentry *d_events) | |
395 | { | |
396 | struct event_subsystem *system; | |
397 | ||
398 | /* First see if we did not already create this dir */ | |
399 | list_for_each_entry(system, &event_subsystems, list) { | |
400 | if (strcmp(system->name, name) == 0) | |
401 | return system->entry; | |
402 | } | |
403 | ||
404 | /* need to create new entry */ | |
405 | system = kmalloc(sizeof(*system), GFP_KERNEL); | |
406 | if (!system) { | |
407 | pr_warning("No memory to create event subsystem %s\n", | |
408 | name); | |
409 | return d_events; | |
410 | } | |
411 | ||
412 | system->entry = debugfs_create_dir(name, d_events); | |
413 | if (!system->entry) { | |
414 | pr_warning("Could not create event subsystem %s\n", | |
415 | name); | |
416 | kfree(system); | |
417 | return d_events; | |
418 | } | |
419 | ||
420 | system->name = name; | |
421 | list_add(&system->list, &event_subsystems); | |
422 | ||
423 | return system->entry; | |
424 | } | |
425 | ||
1473e441 SR |
426 | static int |
427 | event_create_dir(struct ftrace_event_call *call, struct dentry *d_events) | |
428 | { | |
429 | struct dentry *entry; | |
430 | ||
6ecc2d1c SR |
431 | /* |
432 | * If the trace point header did not define TRACE_SYSTEM | |
433 | * then the system would be called "TRACE_SYSTEM". | |
434 | */ | |
435 | if (strcmp(call->system, "TRACE_SYSTEM") != 0) | |
436 | d_events = event_subsystem_dir(call->system, d_events); | |
437 | ||
1473e441 SR |
438 | call->dir = debugfs_create_dir(call->name, d_events); |
439 | if (!call->dir) { | |
440 | pr_warning("Could not create debugfs " | |
441 | "'%s' directory\n", call->name); | |
442 | return -1; | |
443 | } | |
444 | ||
445 | entry = debugfs_create_file("enable", 0644, call->dir, call, | |
446 | &ftrace_enable_fops); | |
447 | if (!entry) | |
448 | pr_warning("Could not create debugfs " | |
449 | "'%s/enable' entry\n", call->name); | |
450 | ||
451 | return 0; | |
452 | } | |
453 | ||
b77e38aa SR |
454 | static __init int event_trace_init(void) |
455 | { | |
1473e441 | 456 | struct ftrace_event_call *call = __start_ftrace_events; |
b77e38aa SR |
457 | struct dentry *d_tracer; |
458 | struct dentry *entry; | |
1473e441 | 459 | struct dentry *d_events; |
b77e38aa SR |
460 | |
461 | d_tracer = tracing_init_dentry(); | |
462 | if (!d_tracer) | |
463 | return 0; | |
464 | ||
465 | entry = debugfs_create_file("available_events", 0444, d_tracer, | |
466 | (void *)&show_event_seq_ops, | |
467 | &ftrace_avail_fops); | |
468 | if (!entry) | |
469 | pr_warning("Could not create debugfs " | |
470 | "'available_events' entry\n"); | |
471 | ||
472 | entry = debugfs_create_file("set_event", 0644, d_tracer, | |
473 | (void *)&show_set_event_seq_ops, | |
474 | &ftrace_set_event_fops); | |
475 | if (!entry) | |
476 | pr_warning("Could not create debugfs " | |
477 | "'set_event' entry\n"); | |
478 | ||
1473e441 SR |
479 | d_events = event_trace_events_dir(); |
480 | if (!d_events) | |
481 | return 0; | |
482 | ||
483 | events_for_each(call) { | |
484 | /* The linker may leave blanks */ | |
485 | if (!call->name) | |
486 | continue; | |
487 | event_create_dir(call, d_events); | |
488 | } | |
489 | ||
b77e38aa SR |
490 | return 0; |
491 | } | |
492 | fs_initcall(event_trace_init); |