]>
Commit | Line | Data |
---|---|---|
16444a8a ACM |
1 | /* |
2 | * Infrastructure for profiling code inserted by 'gcc -pg'. | |
3 | * | |
4 | * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> | |
5 | * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com> | |
6 | * | |
7 | * Originally ported from the -rt patch by: | |
8 | * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com> | |
9 | * | |
10 | * Based on code in the latency_tracer, that is: | |
11 | * | |
12 | * Copyright (C) 2004-2006 Ingo Molnar | |
13 | * Copyright (C) 2004 William Lee Irwin III | |
14 | */ | |
15 | ||
3d083395 SR |
16 | #include <linux/stop_machine.h> |
17 | #include <linux/clocksource.h> | |
18 | #include <linux/kallsyms.h> | |
5072c59f SR |
19 | #include <linux/seq_file.h> |
20 | #include <linux/debugfs.h> | |
3d083395 SR |
21 | #include <linux/kthread.h> |
22 | #include <linux/hardirq.h> | |
16444a8a | 23 | #include <linux/ftrace.h> |
5072c59f | 24 | #include <linux/uaccess.h> |
b0fc494f | 25 | #include <linux/sysctl.h> |
3d083395 | 26 | #include <linux/hash.h> |
5072c59f | 27 | #include <linux/ctype.h> |
3d083395 SR |
28 | #include <linux/list.h> |
29 | ||
30 | #include "trace.h" | |
16444a8a | 31 | |
4eebcc81 SR |
32 | /* ftrace_enabled is a method to turn ftrace on or off */ |
33 | int ftrace_enabled __read_mostly; | |
d61f82d0 | 34 | static int last_ftrace_enabled; |
b0fc494f | 35 | |
4eebcc81 SR |
36 | /* |
37 | * ftrace_disabled is set when an anomaly is discovered. | |
38 | * ftrace_disabled is much stronger than ftrace_enabled. | |
39 | */ | |
40 | static int ftrace_disabled __read_mostly; | |
41 | ||
3d083395 | 42 | static DEFINE_SPINLOCK(ftrace_lock); |
b0fc494f SR |
43 | static DEFINE_MUTEX(ftrace_sysctl_lock); |
44 | ||
16444a8a ACM |
45 | static struct ftrace_ops ftrace_list_end __read_mostly = |
46 | { | |
47 | .func = ftrace_stub, | |
48 | }; | |
49 | ||
50 | static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end; | |
51 | ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; | |
52 | ||
53 | /* mcount is defined per arch in assembly */ | |
54 | EXPORT_SYMBOL(mcount); | |
55 | ||
e309b41d | 56 | void ftrace_list_func(unsigned long ip, unsigned long parent_ip) |
16444a8a ACM |
57 | { |
58 | struct ftrace_ops *op = ftrace_list; | |
59 | ||
60 | /* in case someone actually ports this to alpha! */ | |
61 | read_barrier_depends(); | |
62 | ||
63 | while (op != &ftrace_list_end) { | |
64 | /* silly alpha */ | |
65 | read_barrier_depends(); | |
66 | op->func(ip, parent_ip); | |
67 | op = op->next; | |
68 | }; | |
69 | } | |
70 | ||
71 | /** | |
3d083395 | 72 | * clear_ftrace_function - reset the ftrace function |
16444a8a | 73 | * |
3d083395 SR |
74 | * This NULLs the ftrace function and in essence stops |
75 | * tracing. There may be lag | |
16444a8a | 76 | */ |
3d083395 | 77 | void clear_ftrace_function(void) |
16444a8a | 78 | { |
3d083395 SR |
79 | ftrace_trace_function = ftrace_stub; |
80 | } | |
81 | ||
e309b41d | 82 | static int __register_ftrace_function(struct ftrace_ops *ops) |
3d083395 SR |
83 | { |
84 | /* Should never be called by interrupts */ | |
85 | spin_lock(&ftrace_lock); | |
16444a8a | 86 | |
16444a8a ACM |
87 | ops->next = ftrace_list; |
88 | /* | |
89 | * We are entering ops into the ftrace_list but another | |
90 | * CPU might be walking that list. We need to make sure | |
91 | * the ops->next pointer is valid before another CPU sees | |
92 | * the ops pointer included into the ftrace_list. | |
93 | */ | |
94 | smp_wmb(); | |
95 | ftrace_list = ops; | |
3d083395 | 96 | |
b0fc494f SR |
97 | if (ftrace_enabled) { |
98 | /* | |
99 | * For one func, simply call it directly. | |
100 | * For more than one func, call the chain. | |
101 | */ | |
102 | if (ops->next == &ftrace_list_end) | |
103 | ftrace_trace_function = ops->func; | |
104 | else | |
105 | ftrace_trace_function = ftrace_list_func; | |
106 | } | |
3d083395 SR |
107 | |
108 | spin_unlock(&ftrace_lock); | |
16444a8a ACM |
109 | |
110 | return 0; | |
111 | } | |
112 | ||
e309b41d | 113 | static int __unregister_ftrace_function(struct ftrace_ops *ops) |
16444a8a | 114 | { |
16444a8a ACM |
115 | struct ftrace_ops **p; |
116 | int ret = 0; | |
117 | ||
3d083395 | 118 | spin_lock(&ftrace_lock); |
16444a8a ACM |
119 | |
120 | /* | |
3d083395 SR |
121 | * If we are removing the last function, then simply point |
122 | * to the ftrace_stub. | |
16444a8a ACM |
123 | */ |
124 | if (ftrace_list == ops && ops->next == &ftrace_list_end) { | |
125 | ftrace_trace_function = ftrace_stub; | |
126 | ftrace_list = &ftrace_list_end; | |
127 | goto out; | |
128 | } | |
129 | ||
130 | for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next) | |
131 | if (*p == ops) | |
132 | break; | |
133 | ||
134 | if (*p != ops) { | |
135 | ret = -1; | |
136 | goto out; | |
137 | } | |
138 | ||
139 | *p = (*p)->next; | |
140 | ||
b0fc494f SR |
141 | if (ftrace_enabled) { |
142 | /* If we only have one func left, then call that directly */ | |
143 | if (ftrace_list == &ftrace_list_end || | |
144 | ftrace_list->next == &ftrace_list_end) | |
145 | ftrace_trace_function = ftrace_list->func; | |
146 | } | |
16444a8a ACM |
147 | |
148 | out: | |
3d083395 SR |
149 | spin_unlock(&ftrace_lock); |
150 | ||
151 | return ret; | |
152 | } | |
153 | ||
154 | #ifdef CONFIG_DYNAMIC_FTRACE | |
155 | ||
e1c08bdd SR |
156 | static struct task_struct *ftraced_task; |
157 | static DECLARE_WAIT_QUEUE_HEAD(ftraced_waiters); | |
158 | static unsigned long ftraced_iteration_counter; | |
159 | ||
d61f82d0 SR |
160 | enum { |
161 | FTRACE_ENABLE_CALLS = (1 << 0), | |
162 | FTRACE_DISABLE_CALLS = (1 << 1), | |
163 | FTRACE_UPDATE_TRACE_FUNC = (1 << 2), | |
164 | FTRACE_ENABLE_MCOUNT = (1 << 3), | |
165 | FTRACE_DISABLE_MCOUNT = (1 << 4), | |
166 | }; | |
167 | ||
5072c59f SR |
168 | static int ftrace_filtered; |
169 | ||
3d083395 SR |
170 | static struct hlist_head ftrace_hash[FTRACE_HASHSIZE]; |
171 | ||
172 | static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu); | |
173 | ||
174 | static DEFINE_SPINLOCK(ftrace_shutdown_lock); | |
175 | static DEFINE_MUTEX(ftraced_lock); | |
5072c59f | 176 | static DEFINE_MUTEX(ftrace_filter_lock); |
3d083395 | 177 | |
3c1720f0 SR |
178 | struct ftrace_page { |
179 | struct ftrace_page *next; | |
180 | int index; | |
181 | struct dyn_ftrace records[]; | |
182 | } __attribute__((packed)); | |
183 | ||
184 | #define ENTRIES_PER_PAGE \ | |
185 | ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace)) | |
186 | ||
187 | /* estimate from running different kernels */ | |
188 | #define NR_TO_INIT 10000 | |
189 | ||
190 | static struct ftrace_page *ftrace_pages_start; | |
191 | static struct ftrace_page *ftrace_pages; | |
192 | ||
3d083395 SR |
193 | static int ftraced_trigger; |
194 | static int ftraced_suspend; | |
195 | ||
196 | static int ftrace_record_suspend; | |
197 | ||
37ad5084 SR |
198 | static struct dyn_ftrace *ftrace_free_records; |
199 | ||
e309b41d | 200 | static inline int |
9ff9cdb2 | 201 | ftrace_ip_in_hash(unsigned long ip, unsigned long key) |
3d083395 SR |
202 | { |
203 | struct dyn_ftrace *p; | |
204 | struct hlist_node *t; | |
205 | int found = 0; | |
206 | ||
207 | hlist_for_each_entry(p, t, &ftrace_hash[key], node) { | |
208 | if (p->ip == ip) { | |
209 | found = 1; | |
210 | break; | |
211 | } | |
212 | } | |
213 | ||
214 | return found; | |
215 | } | |
216 | ||
e309b41d | 217 | static inline void |
3d083395 SR |
218 | ftrace_add_hash(struct dyn_ftrace *node, unsigned long key) |
219 | { | |
220 | hlist_add_head(&node->node, &ftrace_hash[key]); | |
221 | } | |
222 | ||
e309b41d | 223 | static void ftrace_free_rec(struct dyn_ftrace *rec) |
37ad5084 SR |
224 | { |
225 | /* no locking, only called from kstop_machine */ | |
226 | ||
227 | rec->ip = (unsigned long)ftrace_free_records; | |
228 | ftrace_free_records = rec; | |
229 | rec->flags |= FTRACE_FL_FREE; | |
230 | } | |
231 | ||
e309b41d | 232 | static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip) |
3c1720f0 | 233 | { |
37ad5084 SR |
234 | struct dyn_ftrace *rec; |
235 | ||
236 | /* First check for freed records */ | |
237 | if (ftrace_free_records) { | |
238 | rec = ftrace_free_records; | |
239 | ||
37ad5084 SR |
240 | if (unlikely(!(rec->flags & FTRACE_FL_FREE))) { |
241 | WARN_ON_ONCE(1); | |
242 | ftrace_free_records = NULL; | |
4eebcc81 SR |
243 | ftrace_disabled = 1; |
244 | ftrace_enabled = 0; | |
37ad5084 SR |
245 | return NULL; |
246 | } | |
247 | ||
248 | ftrace_free_records = (void *)rec->ip; | |
249 | memset(rec, 0, sizeof(*rec)); | |
250 | return rec; | |
251 | } | |
252 | ||
3c1720f0 SR |
253 | if (ftrace_pages->index == ENTRIES_PER_PAGE) { |
254 | if (!ftrace_pages->next) | |
255 | return NULL; | |
256 | ftrace_pages = ftrace_pages->next; | |
257 | } | |
258 | ||
259 | return &ftrace_pages->records[ftrace_pages->index++]; | |
260 | } | |
261 | ||
e309b41d | 262 | static void |
d61f82d0 | 263 | ftrace_record_ip(unsigned long ip) |
3d083395 SR |
264 | { |
265 | struct dyn_ftrace *node; | |
266 | unsigned long flags; | |
267 | unsigned long key; | |
268 | int resched; | |
269 | int atomic; | |
2bb6f8d6 | 270 | int cpu; |
3d083395 | 271 | |
4eebcc81 | 272 | if (!ftrace_enabled || ftrace_disabled) |
d61f82d0 SR |
273 | return; |
274 | ||
3d083395 SR |
275 | resched = need_resched(); |
276 | preempt_disable_notrace(); | |
277 | ||
2bb6f8d6 SR |
278 | /* |
279 | * We simply need to protect against recursion. | |
280 | * Use the the raw version of smp_processor_id and not | |
281 | * __get_cpu_var which can call debug hooks that can | |
282 | * cause a recursive crash here. | |
283 | */ | |
284 | cpu = raw_smp_processor_id(); | |
285 | per_cpu(ftrace_shutdown_disable_cpu, cpu)++; | |
286 | if (per_cpu(ftrace_shutdown_disable_cpu, cpu) != 1) | |
3d083395 SR |
287 | goto out; |
288 | ||
289 | if (unlikely(ftrace_record_suspend)) | |
290 | goto out; | |
291 | ||
292 | key = hash_long(ip, FTRACE_HASHBITS); | |
293 | ||
294 | WARN_ON_ONCE(key >= FTRACE_HASHSIZE); | |
295 | ||
296 | if (ftrace_ip_in_hash(ip, key)) | |
297 | goto out; | |
298 | ||
299 | atomic = irqs_disabled(); | |
300 | ||
301 | spin_lock_irqsave(&ftrace_shutdown_lock, flags); | |
302 | ||
303 | /* This ip may have hit the hash before the lock */ | |
304 | if (ftrace_ip_in_hash(ip, key)) | |
305 | goto out_unlock; | |
306 | ||
307 | /* | |
308 | * There's a slight race that the ftraced will update the | |
d61f82d0 | 309 | * hash and reset here. If it is already converted, skip it. |
3d083395 | 310 | */ |
d61f82d0 SR |
311 | if (ftrace_ip_converted(ip)) |
312 | goto out_unlock; | |
313 | ||
314 | node = ftrace_alloc_dyn_node(ip); | |
3d083395 SR |
315 | if (!node) |
316 | goto out_unlock; | |
317 | ||
318 | node->ip = ip; | |
319 | ||
320 | ftrace_add_hash(node, key); | |
321 | ||
322 | ftraced_trigger = 1; | |
323 | ||
324 | out_unlock: | |
325 | spin_unlock_irqrestore(&ftrace_shutdown_lock, flags); | |
326 | out: | |
2bb6f8d6 | 327 | per_cpu(ftrace_shutdown_disable_cpu, cpu)--; |
3d083395 SR |
328 | |
329 | /* prevent recursion with scheduler */ | |
330 | if (resched) | |
331 | preempt_enable_no_resched_notrace(); | |
332 | else | |
333 | preempt_enable_notrace(); | |
334 | } | |
335 | ||
caf8cdeb SR |
336 | #define FTRACE_ADDR ((long)(ftrace_caller)) |
337 | #define MCOUNT_ADDR ((long)(mcount)) | |
3c1720f0 | 338 | |
e309b41d | 339 | static void |
5072c59f SR |
340 | __ftrace_replace_code(struct dyn_ftrace *rec, |
341 | unsigned char *old, unsigned char *new, int enable) | |
342 | { | |
343 | unsigned long ip; | |
344 | int failed; | |
345 | ||
346 | ip = rec->ip; | |
347 | ||
348 | if (ftrace_filtered && enable) { | |
349 | unsigned long fl; | |
350 | /* | |
351 | * If filtering is on: | |
352 | * | |
353 | * If this record is set to be filtered and | |
354 | * is enabled then do nothing. | |
355 | * | |
356 | * If this record is set to be filtered and | |
357 | * it is not enabled, enable it. | |
358 | * | |
359 | * If this record is not set to be filtered | |
360 | * and it is not enabled do nothing. | |
361 | * | |
362 | * If this record is not set to be filtered and | |
363 | * it is enabled, disable it. | |
364 | */ | |
365 | fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED); | |
366 | ||
367 | if ((fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) || | |
368 | (fl == 0)) | |
369 | return; | |
370 | ||
371 | /* | |
372 | * If it is enabled disable it, | |
373 | * otherwise enable it! | |
374 | */ | |
375 | if (fl == FTRACE_FL_ENABLED) { | |
376 | /* swap new and old */ | |
377 | new = old; | |
378 | old = ftrace_call_replace(ip, FTRACE_ADDR); | |
379 | rec->flags &= ~FTRACE_FL_ENABLED; | |
380 | } else { | |
381 | new = ftrace_call_replace(ip, FTRACE_ADDR); | |
382 | rec->flags |= FTRACE_FL_ENABLED; | |
383 | } | |
384 | } else { | |
385 | ||
386 | if (enable) | |
387 | new = ftrace_call_replace(ip, FTRACE_ADDR); | |
388 | else | |
389 | old = ftrace_call_replace(ip, FTRACE_ADDR); | |
390 | ||
391 | if (enable) { | |
392 | if (rec->flags & FTRACE_FL_ENABLED) | |
393 | return; | |
394 | rec->flags |= FTRACE_FL_ENABLED; | |
395 | } else { | |
396 | if (!(rec->flags & FTRACE_FL_ENABLED)) | |
397 | return; | |
398 | rec->flags &= ~FTRACE_FL_ENABLED; | |
399 | } | |
400 | } | |
401 | ||
402 | failed = ftrace_modify_code(ip, old, new); | |
37ad5084 SR |
403 | if (failed) { |
404 | unsigned long key; | |
405 | /* It is possible that the function hasn't been converted yet */ | |
406 | key = hash_long(ip, FTRACE_HASHBITS); | |
407 | if (!ftrace_ip_in_hash(ip, key)) { | |
408 | rec->flags |= FTRACE_FL_FAILED; | |
409 | ftrace_free_rec(rec); | |
410 | } | |
411 | ||
412 | } | |
5072c59f SR |
413 | } |
414 | ||
e309b41d | 415 | static void ftrace_replace_code(int enable) |
3c1720f0 SR |
416 | { |
417 | unsigned char *new = NULL, *old = NULL; | |
418 | struct dyn_ftrace *rec; | |
419 | struct ftrace_page *pg; | |
3c1720f0 SR |
420 | int i; |
421 | ||
5072c59f | 422 | if (enable) |
3c1720f0 SR |
423 | old = ftrace_nop_replace(); |
424 | else | |
425 | new = ftrace_nop_replace(); | |
426 | ||
427 | for (pg = ftrace_pages_start; pg; pg = pg->next) { | |
428 | for (i = 0; i < pg->index; i++) { | |
429 | rec = &pg->records[i]; | |
430 | ||
431 | /* don't modify code that has already faulted */ | |
432 | if (rec->flags & FTRACE_FL_FAILED) | |
433 | continue; | |
434 | ||
5072c59f | 435 | __ftrace_replace_code(rec, old, new, enable); |
3c1720f0 SR |
436 | } |
437 | } | |
438 | } | |
439 | ||
e309b41d | 440 | static void ftrace_shutdown_replenish(void) |
3c1720f0 SR |
441 | { |
442 | if (ftrace_pages->next) | |
443 | return; | |
444 | ||
445 | /* allocate another page */ | |
446 | ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL); | |
447 | } | |
3d083395 | 448 | |
e309b41d | 449 | static void |
d61f82d0 | 450 | ftrace_code_disable(struct dyn_ftrace *rec) |
3c1720f0 SR |
451 | { |
452 | unsigned long ip; | |
453 | unsigned char *nop, *call; | |
454 | int failed; | |
455 | ||
456 | ip = rec->ip; | |
457 | ||
458 | nop = ftrace_nop_replace(); | |
d61f82d0 | 459 | call = ftrace_call_replace(ip, MCOUNT_ADDR); |
3c1720f0 SR |
460 | |
461 | failed = ftrace_modify_code(ip, call, nop); | |
37ad5084 | 462 | if (failed) { |
3c1720f0 | 463 | rec->flags |= FTRACE_FL_FAILED; |
37ad5084 SR |
464 | ftrace_free_rec(rec); |
465 | } | |
3c1720f0 SR |
466 | } |
467 | ||
e309b41d | 468 | static int __ftrace_modify_code(void *data) |
3d083395 | 469 | { |
d61f82d0 SR |
470 | unsigned long addr; |
471 | int *command = data; | |
472 | ||
473 | if (*command & FTRACE_ENABLE_CALLS) | |
474 | ftrace_replace_code(1); | |
475 | else if (*command & FTRACE_DISABLE_CALLS) | |
476 | ftrace_replace_code(0); | |
477 | ||
478 | if (*command & FTRACE_UPDATE_TRACE_FUNC) | |
479 | ftrace_update_ftrace_func(ftrace_trace_function); | |
480 | ||
481 | if (*command & FTRACE_ENABLE_MCOUNT) { | |
482 | addr = (unsigned long)ftrace_record_ip; | |
483 | ftrace_mcount_set(&addr); | |
484 | } else if (*command & FTRACE_DISABLE_MCOUNT) { | |
485 | addr = (unsigned long)ftrace_stub; | |
486 | ftrace_mcount_set(&addr); | |
487 | } | |
488 | ||
489 | return 0; | |
3d083395 SR |
490 | } |
491 | ||
e309b41d | 492 | static void ftrace_run_update_code(int command) |
3d083395 | 493 | { |
d61f82d0 | 494 | stop_machine_run(__ftrace_modify_code, &command, NR_CPUS); |
3d083395 SR |
495 | } |
496 | ||
d61f82d0 SR |
497 | static ftrace_func_t saved_ftrace_func; |
498 | ||
e309b41d | 499 | static void ftrace_startup(void) |
3d083395 | 500 | { |
d61f82d0 SR |
501 | int command = 0; |
502 | ||
4eebcc81 SR |
503 | if (unlikely(ftrace_disabled)) |
504 | return; | |
505 | ||
3d083395 SR |
506 | mutex_lock(&ftraced_lock); |
507 | ftraced_suspend++; | |
d61f82d0 SR |
508 | if (ftraced_suspend == 1) |
509 | command |= FTRACE_ENABLE_CALLS; | |
510 | ||
511 | if (saved_ftrace_func != ftrace_trace_function) { | |
512 | saved_ftrace_func = ftrace_trace_function; | |
513 | command |= FTRACE_UPDATE_TRACE_FUNC; | |
514 | } | |
515 | ||
516 | if (!command || !ftrace_enabled) | |
3d083395 | 517 | goto out; |
3d083395 | 518 | |
d61f82d0 | 519 | ftrace_run_update_code(command); |
3d083395 SR |
520 | out: |
521 | mutex_unlock(&ftraced_lock); | |
522 | } | |
523 | ||
e309b41d | 524 | static void ftrace_shutdown(void) |
3d083395 | 525 | { |
d61f82d0 SR |
526 | int command = 0; |
527 | ||
4eebcc81 SR |
528 | if (unlikely(ftrace_disabled)) |
529 | return; | |
530 | ||
3d083395 SR |
531 | mutex_lock(&ftraced_lock); |
532 | ftraced_suspend--; | |
d61f82d0 SR |
533 | if (!ftraced_suspend) |
534 | command |= FTRACE_DISABLE_CALLS; | |
3d083395 | 535 | |
d61f82d0 SR |
536 | if (saved_ftrace_func != ftrace_trace_function) { |
537 | saved_ftrace_func = ftrace_trace_function; | |
538 | command |= FTRACE_UPDATE_TRACE_FUNC; | |
539 | } | |
3d083395 | 540 | |
d61f82d0 SR |
541 | if (!command || !ftrace_enabled) |
542 | goto out; | |
543 | ||
544 | ftrace_run_update_code(command); | |
3d083395 SR |
545 | out: |
546 | mutex_unlock(&ftraced_lock); | |
547 | } | |
548 | ||
e309b41d | 549 | static void ftrace_startup_sysctl(void) |
b0fc494f | 550 | { |
d61f82d0 SR |
551 | int command = FTRACE_ENABLE_MCOUNT; |
552 | ||
4eebcc81 SR |
553 | if (unlikely(ftrace_disabled)) |
554 | return; | |
555 | ||
b0fc494f | 556 | mutex_lock(&ftraced_lock); |
d61f82d0 SR |
557 | /* Force update next time */ |
558 | saved_ftrace_func = NULL; | |
b0fc494f SR |
559 | /* ftraced_suspend is true if we want ftrace running */ |
560 | if (ftraced_suspend) | |
d61f82d0 SR |
561 | command |= FTRACE_ENABLE_CALLS; |
562 | ||
563 | ftrace_run_update_code(command); | |
b0fc494f SR |
564 | mutex_unlock(&ftraced_lock); |
565 | } | |
566 | ||
e309b41d | 567 | static void ftrace_shutdown_sysctl(void) |
b0fc494f | 568 | { |
d61f82d0 SR |
569 | int command = FTRACE_DISABLE_MCOUNT; |
570 | ||
4eebcc81 SR |
571 | if (unlikely(ftrace_disabled)) |
572 | return; | |
573 | ||
b0fc494f SR |
574 | mutex_lock(&ftraced_lock); |
575 | /* ftraced_suspend is true if ftrace is running */ | |
576 | if (ftraced_suspend) | |
d61f82d0 SR |
577 | command |= FTRACE_DISABLE_CALLS; |
578 | ||
579 | ftrace_run_update_code(command); | |
b0fc494f SR |
580 | mutex_unlock(&ftraced_lock); |
581 | } | |
582 | ||
3d083395 SR |
583 | static cycle_t ftrace_update_time; |
584 | static unsigned long ftrace_update_cnt; | |
585 | unsigned long ftrace_update_tot_cnt; | |
586 | ||
e309b41d | 587 | static int __ftrace_update_code(void *ignore) |
3d083395 SR |
588 | { |
589 | struct dyn_ftrace *p; | |
590 | struct hlist_head head; | |
591 | struct hlist_node *t; | |
d61f82d0 | 592 | int save_ftrace_enabled; |
3d083395 SR |
593 | cycle_t start, stop; |
594 | int i; | |
595 | ||
d61f82d0 SR |
596 | /* Don't be recording funcs now */ |
597 | save_ftrace_enabled = ftrace_enabled; | |
598 | ftrace_enabled = 0; | |
3d083395 | 599 | |
750ed1a4 | 600 | start = ftrace_now(raw_smp_processor_id()); |
3d083395 SR |
601 | ftrace_update_cnt = 0; |
602 | ||
603 | /* No locks needed, the machine is stopped! */ | |
604 | for (i = 0; i < FTRACE_HASHSIZE; i++) { | |
605 | if (hlist_empty(&ftrace_hash[i])) | |
606 | continue; | |
607 | ||
608 | head = ftrace_hash[i]; | |
609 | INIT_HLIST_HEAD(&ftrace_hash[i]); | |
610 | ||
611 | /* all CPUS are stopped, we are safe to modify code */ | |
612 | hlist_for_each_entry(p, t, &head, node) { | |
d61f82d0 | 613 | ftrace_code_disable(p); |
3d083395 SR |
614 | ftrace_update_cnt++; |
615 | } | |
616 | ||
617 | } | |
618 | ||
750ed1a4 | 619 | stop = ftrace_now(raw_smp_processor_id()); |
3d083395 SR |
620 | ftrace_update_time = stop - start; |
621 | ftrace_update_tot_cnt += ftrace_update_cnt; | |
622 | ||
d61f82d0 | 623 | ftrace_enabled = save_ftrace_enabled; |
16444a8a ACM |
624 | |
625 | return 0; | |
626 | } | |
627 | ||
e309b41d | 628 | static void ftrace_update_code(void) |
3d083395 | 629 | { |
4eebcc81 SR |
630 | if (unlikely(ftrace_disabled)) |
631 | return; | |
632 | ||
3d083395 SR |
633 | stop_machine_run(__ftrace_update_code, NULL, NR_CPUS); |
634 | } | |
635 | ||
e309b41d | 636 | static int ftraced(void *ignore) |
3d083395 SR |
637 | { |
638 | unsigned long usecs; | |
639 | ||
3d083395 SR |
640 | while (!kthread_should_stop()) { |
641 | ||
07a267cd SR |
642 | set_current_state(TASK_INTERRUPTIBLE); |
643 | ||
3d083395 SR |
644 | /* check once a second */ |
645 | schedule_timeout(HZ); | |
646 | ||
4eebcc81 SR |
647 | if (unlikely(ftrace_disabled)) |
648 | continue; | |
649 | ||
b0fc494f | 650 | mutex_lock(&ftrace_sysctl_lock); |
3d083395 | 651 | mutex_lock(&ftraced_lock); |
b0fc494f | 652 | if (ftrace_enabled && ftraced_trigger && !ftraced_suspend) { |
3d083395 SR |
653 | ftrace_record_suspend++; |
654 | ftrace_update_code(); | |
655 | usecs = nsecs_to_usecs(ftrace_update_time); | |
656 | if (ftrace_update_tot_cnt > 100000) { | |
657 | ftrace_update_tot_cnt = 0; | |
658 | pr_info("hm, dftrace overflow: %lu change%s" | |
659 | " (%lu total) in %lu usec%s\n", | |
660 | ftrace_update_cnt, | |
661 | ftrace_update_cnt != 1 ? "s" : "", | |
662 | ftrace_update_tot_cnt, | |
663 | usecs, usecs != 1 ? "s" : ""); | |
4eebcc81 | 664 | ftrace_disabled = 1; |
3d083395 SR |
665 | WARN_ON_ONCE(1); |
666 | } | |
667 | ftraced_trigger = 0; | |
668 | ftrace_record_suspend--; | |
669 | } | |
e1c08bdd | 670 | ftraced_iteration_counter++; |
3d083395 | 671 | mutex_unlock(&ftraced_lock); |
b0fc494f | 672 | mutex_unlock(&ftrace_sysctl_lock); |
3d083395 | 673 | |
e1c08bdd SR |
674 | wake_up_interruptible(&ftraced_waiters); |
675 | ||
3d083395 | 676 | ftrace_shutdown_replenish(); |
3d083395 SR |
677 | } |
678 | __set_current_state(TASK_RUNNING); | |
679 | return 0; | |
680 | } | |
681 | ||
3c1720f0 SR |
682 | static int __init ftrace_dyn_table_alloc(void) |
683 | { | |
684 | struct ftrace_page *pg; | |
685 | int cnt; | |
686 | int i; | |
3c1720f0 SR |
687 | |
688 | /* allocate a few pages */ | |
689 | ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL); | |
690 | if (!ftrace_pages_start) | |
691 | return -1; | |
692 | ||
693 | /* | |
694 | * Allocate a few more pages. | |
695 | * | |
696 | * TODO: have some parser search vmlinux before | |
697 | * final linking to find all calls to ftrace. | |
698 | * Then we can: | |
699 | * a) know how many pages to allocate. | |
700 | * and/or | |
701 | * b) set up the table then. | |
702 | * | |
703 | * The dynamic code is still necessary for | |
704 | * modules. | |
705 | */ | |
706 | ||
707 | pg = ftrace_pages = ftrace_pages_start; | |
708 | ||
709 | cnt = NR_TO_INIT / ENTRIES_PER_PAGE; | |
710 | ||
711 | for (i = 0; i < cnt; i++) { | |
712 | pg->next = (void *)get_zeroed_page(GFP_KERNEL); | |
713 | ||
714 | /* If we fail, we'll try later anyway */ | |
715 | if (!pg->next) | |
716 | break; | |
717 | ||
718 | pg = pg->next; | |
719 | } | |
720 | ||
721 | return 0; | |
722 | } | |
723 | ||
5072c59f SR |
724 | enum { |
725 | FTRACE_ITER_FILTER = (1 << 0), | |
726 | FTRACE_ITER_CONT = (1 << 1), | |
727 | }; | |
728 | ||
729 | #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */ | |
730 | ||
731 | struct ftrace_iterator { | |
732 | loff_t pos; | |
733 | struct ftrace_page *pg; | |
734 | unsigned idx; | |
735 | unsigned flags; | |
736 | unsigned char buffer[FTRACE_BUFF_MAX+1]; | |
737 | unsigned buffer_idx; | |
738 | unsigned filtered; | |
739 | }; | |
740 | ||
e309b41d | 741 | static void * |
5072c59f SR |
742 | t_next(struct seq_file *m, void *v, loff_t *pos) |
743 | { | |
744 | struct ftrace_iterator *iter = m->private; | |
745 | struct dyn_ftrace *rec = NULL; | |
746 | ||
747 | (*pos)++; | |
748 | ||
749 | retry: | |
750 | if (iter->idx >= iter->pg->index) { | |
751 | if (iter->pg->next) { | |
752 | iter->pg = iter->pg->next; | |
753 | iter->idx = 0; | |
754 | goto retry; | |
755 | } | |
756 | } else { | |
757 | rec = &iter->pg->records[iter->idx++]; | |
758 | if ((rec->flags & FTRACE_FL_FAILED) || | |
759 | ((iter->flags & FTRACE_ITER_FILTER) && | |
760 | !(rec->flags & FTRACE_FL_FILTER))) { | |
761 | rec = NULL; | |
762 | goto retry; | |
763 | } | |
764 | } | |
765 | ||
766 | iter->pos = *pos; | |
767 | ||
768 | return rec; | |
769 | } | |
770 | ||
771 | static void *t_start(struct seq_file *m, loff_t *pos) | |
772 | { | |
773 | struct ftrace_iterator *iter = m->private; | |
774 | void *p = NULL; | |
775 | loff_t l = -1; | |
776 | ||
777 | if (*pos != iter->pos) { | |
778 | for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l)) | |
779 | ; | |
780 | } else { | |
781 | l = *pos; | |
782 | p = t_next(m, p, &l); | |
783 | } | |
784 | ||
785 | return p; | |
786 | } | |
787 | ||
788 | static void t_stop(struct seq_file *m, void *p) | |
789 | { | |
790 | } | |
791 | ||
792 | static int t_show(struct seq_file *m, void *v) | |
793 | { | |
794 | struct dyn_ftrace *rec = v; | |
795 | char str[KSYM_SYMBOL_LEN]; | |
796 | ||
797 | if (!rec) | |
798 | return 0; | |
799 | ||
800 | kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); | |
801 | ||
802 | seq_printf(m, "%s\n", str); | |
803 | ||
804 | return 0; | |
805 | } | |
806 | ||
807 | static struct seq_operations show_ftrace_seq_ops = { | |
808 | .start = t_start, | |
809 | .next = t_next, | |
810 | .stop = t_stop, | |
811 | .show = t_show, | |
812 | }; | |
813 | ||
e309b41d | 814 | static int |
5072c59f SR |
815 | ftrace_avail_open(struct inode *inode, struct file *file) |
816 | { | |
817 | struct ftrace_iterator *iter; | |
818 | int ret; | |
819 | ||
4eebcc81 SR |
820 | if (unlikely(ftrace_disabled)) |
821 | return -ENODEV; | |
822 | ||
5072c59f SR |
823 | iter = kzalloc(sizeof(*iter), GFP_KERNEL); |
824 | if (!iter) | |
825 | return -ENOMEM; | |
826 | ||
827 | iter->pg = ftrace_pages_start; | |
828 | iter->pos = -1; | |
829 | ||
830 | ret = seq_open(file, &show_ftrace_seq_ops); | |
831 | if (!ret) { | |
832 | struct seq_file *m = file->private_data; | |
4bf39a94 | 833 | |
5072c59f | 834 | m->private = iter; |
4bf39a94 | 835 | } else { |
5072c59f | 836 | kfree(iter); |
4bf39a94 | 837 | } |
5072c59f SR |
838 | |
839 | return ret; | |
840 | } | |
841 | ||
842 | int ftrace_avail_release(struct inode *inode, struct file *file) | |
843 | { | |
844 | struct seq_file *m = (struct seq_file *)file->private_data; | |
845 | struct ftrace_iterator *iter = m->private; | |
846 | ||
847 | seq_release(inode, file); | |
848 | kfree(iter); | |
4bf39a94 | 849 | |
5072c59f SR |
850 | return 0; |
851 | } | |
852 | ||
e309b41d | 853 | static void ftrace_filter_reset(void) |
5072c59f SR |
854 | { |
855 | struct ftrace_page *pg; | |
856 | struct dyn_ftrace *rec; | |
857 | unsigned i; | |
858 | ||
859 | /* keep kstop machine from running */ | |
860 | preempt_disable(); | |
861 | ftrace_filtered = 0; | |
862 | pg = ftrace_pages_start; | |
863 | while (pg) { | |
864 | for (i = 0; i < pg->index; i++) { | |
865 | rec = &pg->records[i]; | |
866 | if (rec->flags & FTRACE_FL_FAILED) | |
867 | continue; | |
868 | rec->flags &= ~FTRACE_FL_FILTER; | |
869 | } | |
870 | pg = pg->next; | |
871 | } | |
872 | preempt_enable(); | |
873 | } | |
874 | ||
e309b41d | 875 | static int |
5072c59f SR |
876 | ftrace_filter_open(struct inode *inode, struct file *file) |
877 | { | |
878 | struct ftrace_iterator *iter; | |
879 | int ret = 0; | |
880 | ||
4eebcc81 SR |
881 | if (unlikely(ftrace_disabled)) |
882 | return -ENODEV; | |
883 | ||
5072c59f SR |
884 | iter = kzalloc(sizeof(*iter), GFP_KERNEL); |
885 | if (!iter) | |
886 | return -ENOMEM; | |
887 | ||
888 | mutex_lock(&ftrace_filter_lock); | |
889 | if ((file->f_mode & FMODE_WRITE) && | |
890 | !(file->f_flags & O_APPEND)) | |
891 | ftrace_filter_reset(); | |
892 | ||
893 | if (file->f_mode & FMODE_READ) { | |
894 | iter->pg = ftrace_pages_start; | |
895 | iter->pos = -1; | |
896 | iter->flags = FTRACE_ITER_FILTER; | |
897 | ||
898 | ret = seq_open(file, &show_ftrace_seq_ops); | |
899 | if (!ret) { | |
900 | struct seq_file *m = file->private_data; | |
901 | m->private = iter; | |
902 | } else | |
903 | kfree(iter); | |
904 | } else | |
905 | file->private_data = iter; | |
906 | mutex_unlock(&ftrace_filter_lock); | |
907 | ||
908 | return ret; | |
909 | } | |
910 | ||
e309b41d | 911 | static ssize_t |
5072c59f SR |
912 | ftrace_filter_read(struct file *file, char __user *ubuf, |
913 | size_t cnt, loff_t *ppos) | |
914 | { | |
915 | if (file->f_mode & FMODE_READ) | |
916 | return seq_read(file, ubuf, cnt, ppos); | |
917 | else | |
918 | return -EPERM; | |
919 | } | |
920 | ||
e309b41d | 921 | static loff_t |
5072c59f SR |
922 | ftrace_filter_lseek(struct file *file, loff_t offset, int origin) |
923 | { | |
924 | loff_t ret; | |
925 | ||
926 | if (file->f_mode & FMODE_READ) | |
927 | ret = seq_lseek(file, offset, origin); | |
928 | else | |
929 | file->f_pos = ret = 1; | |
930 | ||
931 | return ret; | |
932 | } | |
933 | ||
934 | enum { | |
935 | MATCH_FULL, | |
936 | MATCH_FRONT_ONLY, | |
937 | MATCH_MIDDLE_ONLY, | |
938 | MATCH_END_ONLY, | |
939 | }; | |
940 | ||
e309b41d | 941 | static void |
5072c59f SR |
942 | ftrace_match(unsigned char *buff, int len) |
943 | { | |
944 | char str[KSYM_SYMBOL_LEN]; | |
945 | char *search = NULL; | |
946 | struct ftrace_page *pg; | |
947 | struct dyn_ftrace *rec; | |
948 | int type = MATCH_FULL; | |
949 | unsigned i, match = 0, search_len = 0; | |
950 | ||
951 | for (i = 0; i < len; i++) { | |
952 | if (buff[i] == '*') { | |
953 | if (!i) { | |
954 | search = buff + i + 1; | |
955 | type = MATCH_END_ONLY; | |
956 | search_len = len - (i + 1); | |
957 | } else { | |
958 | if (type == MATCH_END_ONLY) { | |
959 | type = MATCH_MIDDLE_ONLY; | |
960 | } else { | |
961 | match = i; | |
962 | type = MATCH_FRONT_ONLY; | |
963 | } | |
964 | buff[i] = 0; | |
965 | break; | |
966 | } | |
967 | } | |
968 | } | |
969 | ||
970 | /* keep kstop machine from running */ | |
971 | preempt_disable(); | |
972 | ftrace_filtered = 1; | |
973 | pg = ftrace_pages_start; | |
974 | while (pg) { | |
975 | for (i = 0; i < pg->index; i++) { | |
976 | int matched = 0; | |
977 | char *ptr; | |
978 | ||
979 | rec = &pg->records[i]; | |
980 | if (rec->flags & FTRACE_FL_FAILED) | |
981 | continue; | |
982 | kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); | |
983 | switch (type) { | |
984 | case MATCH_FULL: | |
985 | if (strcmp(str, buff) == 0) | |
986 | matched = 1; | |
987 | break; | |
988 | case MATCH_FRONT_ONLY: | |
989 | if (memcmp(str, buff, match) == 0) | |
990 | matched = 1; | |
991 | break; | |
992 | case MATCH_MIDDLE_ONLY: | |
993 | if (strstr(str, search)) | |
994 | matched = 1; | |
995 | break; | |
996 | case MATCH_END_ONLY: | |
997 | ptr = strstr(str, search); | |
998 | if (ptr && (ptr[search_len] == 0)) | |
999 | matched = 1; | |
1000 | break; | |
1001 | } | |
1002 | if (matched) | |
1003 | rec->flags |= FTRACE_FL_FILTER; | |
1004 | } | |
1005 | pg = pg->next; | |
1006 | } | |
1007 | preempt_enable(); | |
1008 | } | |
1009 | ||
e309b41d | 1010 | static ssize_t |
5072c59f SR |
1011 | ftrace_filter_write(struct file *file, const char __user *ubuf, |
1012 | size_t cnt, loff_t *ppos) | |
1013 | { | |
1014 | struct ftrace_iterator *iter; | |
1015 | char ch; | |
1016 | size_t read = 0; | |
1017 | ssize_t ret; | |
1018 | ||
1019 | if (!cnt || cnt < 0) | |
1020 | return 0; | |
1021 | ||
1022 | mutex_lock(&ftrace_filter_lock); | |
1023 | ||
1024 | if (file->f_mode & FMODE_READ) { | |
1025 | struct seq_file *m = file->private_data; | |
1026 | iter = m->private; | |
1027 | } else | |
1028 | iter = file->private_data; | |
1029 | ||
1030 | if (!*ppos) { | |
1031 | iter->flags &= ~FTRACE_ITER_CONT; | |
1032 | iter->buffer_idx = 0; | |
1033 | } | |
1034 | ||
1035 | ret = get_user(ch, ubuf++); | |
1036 | if (ret) | |
1037 | goto out; | |
1038 | read++; | |
1039 | cnt--; | |
1040 | ||
1041 | if (!(iter->flags & ~FTRACE_ITER_CONT)) { | |
1042 | /* skip white space */ | |
1043 | while (cnt && isspace(ch)) { | |
1044 | ret = get_user(ch, ubuf++); | |
1045 | if (ret) | |
1046 | goto out; | |
1047 | read++; | |
1048 | cnt--; | |
1049 | } | |
1050 | ||
1051 | ||
1052 | if (isspace(ch)) { | |
1053 | file->f_pos += read; | |
1054 | ret = read; | |
1055 | goto out; | |
1056 | } | |
1057 | ||
1058 | iter->buffer_idx = 0; | |
1059 | } | |
1060 | ||
1061 | while (cnt && !isspace(ch)) { | |
1062 | if (iter->buffer_idx < FTRACE_BUFF_MAX) | |
1063 | iter->buffer[iter->buffer_idx++] = ch; | |
1064 | else { | |
1065 | ret = -EINVAL; | |
1066 | goto out; | |
1067 | } | |
1068 | ret = get_user(ch, ubuf++); | |
1069 | if (ret) | |
1070 | goto out; | |
1071 | read++; | |
1072 | cnt--; | |
1073 | } | |
1074 | ||
1075 | if (isspace(ch)) { | |
1076 | iter->filtered++; | |
1077 | iter->buffer[iter->buffer_idx] = 0; | |
1078 | ftrace_match(iter->buffer, iter->buffer_idx); | |
1079 | iter->buffer_idx = 0; | |
1080 | } else | |
1081 | iter->flags |= FTRACE_ITER_CONT; | |
1082 | ||
1083 | ||
1084 | file->f_pos += read; | |
1085 | ||
1086 | ret = read; | |
1087 | out: | |
1088 | mutex_unlock(&ftrace_filter_lock); | |
1089 | ||
1090 | return ret; | |
1091 | } | |
1092 | ||
77a2b37d SR |
1093 | /** |
1094 | * ftrace_set_filter - set a function to filter on in ftrace | |
1095 | * @buf - the string that holds the function filter text. | |
1096 | * @len - the length of the string. | |
1097 | * @reset - non zero to reset all filters before applying this filter. | |
1098 | * | |
1099 | * Filters denote which functions should be enabled when tracing is enabled. | |
1100 | * If @buf is NULL and reset is set, all functions will be enabled for tracing. | |
1101 | */ | |
e309b41d | 1102 | void ftrace_set_filter(unsigned char *buf, int len, int reset) |
77a2b37d | 1103 | { |
4eebcc81 SR |
1104 | if (unlikely(ftrace_disabled)) |
1105 | return; | |
1106 | ||
77a2b37d SR |
1107 | mutex_lock(&ftrace_filter_lock); |
1108 | if (reset) | |
1109 | ftrace_filter_reset(); | |
1110 | if (buf) | |
1111 | ftrace_match(buf, len); | |
1112 | mutex_unlock(&ftrace_filter_lock); | |
1113 | } | |
1114 | ||
e309b41d | 1115 | static int |
5072c59f SR |
1116 | ftrace_filter_release(struct inode *inode, struct file *file) |
1117 | { | |
1118 | struct seq_file *m = (struct seq_file *)file->private_data; | |
1119 | struct ftrace_iterator *iter; | |
1120 | ||
1121 | mutex_lock(&ftrace_filter_lock); | |
1122 | if (file->f_mode & FMODE_READ) { | |
1123 | iter = m->private; | |
1124 | ||
1125 | seq_release(inode, file); | |
1126 | } else | |
1127 | iter = file->private_data; | |
1128 | ||
1129 | if (iter->buffer_idx) { | |
1130 | iter->filtered++; | |
1131 | iter->buffer[iter->buffer_idx] = 0; | |
1132 | ftrace_match(iter->buffer, iter->buffer_idx); | |
1133 | } | |
1134 | ||
1135 | mutex_lock(&ftrace_sysctl_lock); | |
1136 | mutex_lock(&ftraced_lock); | |
1137 | if (iter->filtered && ftraced_suspend && ftrace_enabled) | |
1138 | ftrace_run_update_code(FTRACE_ENABLE_CALLS); | |
1139 | mutex_unlock(&ftraced_lock); | |
1140 | mutex_unlock(&ftrace_sysctl_lock); | |
1141 | ||
1142 | kfree(iter); | |
1143 | mutex_unlock(&ftrace_filter_lock); | |
1144 | return 0; | |
1145 | } | |
1146 | ||
1147 | static struct file_operations ftrace_avail_fops = { | |
1148 | .open = ftrace_avail_open, | |
1149 | .read = seq_read, | |
1150 | .llseek = seq_lseek, | |
1151 | .release = ftrace_avail_release, | |
1152 | }; | |
1153 | ||
1154 | static struct file_operations ftrace_filter_fops = { | |
1155 | .open = ftrace_filter_open, | |
1156 | .read = ftrace_filter_read, | |
1157 | .write = ftrace_filter_write, | |
1158 | .llseek = ftrace_filter_lseek, | |
1159 | .release = ftrace_filter_release, | |
1160 | }; | |
1161 | ||
e1c08bdd SR |
1162 | /** |
1163 | * ftrace_force_update - force an update to all recording ftrace functions | |
1164 | * | |
1165 | * The ftrace dynamic update daemon only wakes up once a second. | |
1166 | * There may be cases where an update needs to be done immediately | |
1167 | * for tests or internal kernel tracing to begin. This function | |
1168 | * wakes the daemon to do an update and will not return until the | |
1169 | * update is complete. | |
1170 | */ | |
1171 | int ftrace_force_update(void) | |
1172 | { | |
1173 | unsigned long last_counter; | |
1174 | DECLARE_WAITQUEUE(wait, current); | |
1175 | int ret = 0; | |
1176 | ||
4eebcc81 | 1177 | if (unlikely(ftrace_disabled)) |
e1c08bdd SR |
1178 | return -ENODEV; |
1179 | ||
1180 | mutex_lock(&ftraced_lock); | |
1181 | last_counter = ftraced_iteration_counter; | |
1182 | ||
1183 | set_current_state(TASK_INTERRUPTIBLE); | |
1184 | add_wait_queue(&ftraced_waiters, &wait); | |
1185 | ||
4eebcc81 SR |
1186 | if (unlikely(!ftraced_task)) { |
1187 | ret = -ENODEV; | |
1188 | goto out; | |
1189 | } | |
1190 | ||
e1c08bdd SR |
1191 | do { |
1192 | mutex_unlock(&ftraced_lock); | |
1193 | wake_up_process(ftraced_task); | |
1194 | schedule(); | |
1195 | mutex_lock(&ftraced_lock); | |
1196 | if (signal_pending(current)) { | |
1197 | ret = -EINTR; | |
1198 | break; | |
1199 | } | |
1200 | set_current_state(TASK_INTERRUPTIBLE); | |
1201 | } while (last_counter == ftraced_iteration_counter); | |
1202 | ||
4eebcc81 | 1203 | out: |
e1c08bdd SR |
1204 | mutex_unlock(&ftraced_lock); |
1205 | remove_wait_queue(&ftraced_waiters, &wait); | |
1206 | set_current_state(TASK_RUNNING); | |
1207 | ||
1208 | return ret; | |
1209 | } | |
1210 | ||
4eebcc81 SR |
1211 | static void ftrace_force_shutdown(void) |
1212 | { | |
1213 | struct task_struct *task; | |
1214 | int command = FTRACE_DISABLE_CALLS | FTRACE_UPDATE_TRACE_FUNC; | |
1215 | ||
1216 | mutex_lock(&ftraced_lock); | |
1217 | task = ftraced_task; | |
1218 | ftraced_task = NULL; | |
1219 | ftraced_suspend = -1; | |
1220 | ftrace_run_update_code(command); | |
1221 | mutex_unlock(&ftraced_lock); | |
1222 | ||
1223 | if (task) | |
1224 | kthread_stop(task); | |
1225 | } | |
1226 | ||
5072c59f SR |
1227 | static __init int ftrace_init_debugfs(void) |
1228 | { | |
1229 | struct dentry *d_tracer; | |
1230 | struct dentry *entry; | |
1231 | ||
1232 | d_tracer = tracing_init_dentry(); | |
1233 | ||
1234 | entry = debugfs_create_file("available_filter_functions", 0444, | |
1235 | d_tracer, NULL, &ftrace_avail_fops); | |
1236 | if (!entry) | |
1237 | pr_warning("Could not create debugfs " | |
1238 | "'available_filter_functions' entry\n"); | |
1239 | ||
1240 | entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer, | |
1241 | NULL, &ftrace_filter_fops); | |
1242 | if (!entry) | |
1243 | pr_warning("Could not create debugfs " | |
1244 | "'set_ftrace_filter' entry\n"); | |
1245 | return 0; | |
1246 | } | |
1247 | ||
1248 | fs_initcall(ftrace_init_debugfs); | |
1249 | ||
e309b41d | 1250 | static int __init ftrace_dynamic_init(void) |
3d083395 SR |
1251 | { |
1252 | struct task_struct *p; | |
d61f82d0 | 1253 | unsigned long addr; |
3d083395 SR |
1254 | int ret; |
1255 | ||
d61f82d0 | 1256 | addr = (unsigned long)ftrace_record_ip; |
9ff9cdb2 | 1257 | |
d61f82d0 SR |
1258 | stop_machine_run(ftrace_dyn_arch_init, &addr, NR_CPUS); |
1259 | ||
1260 | /* ftrace_dyn_arch_init places the return code in addr */ | |
4eebcc81 SR |
1261 | if (addr) { |
1262 | ret = (int)addr; | |
1263 | goto failed; | |
1264 | } | |
d61f82d0 | 1265 | |
3c1720f0 | 1266 | ret = ftrace_dyn_table_alloc(); |
3d083395 | 1267 | if (ret) |
4eebcc81 | 1268 | goto failed; |
3d083395 SR |
1269 | |
1270 | p = kthread_run(ftraced, NULL, "ftraced"); | |
4eebcc81 SR |
1271 | if (IS_ERR(p)) { |
1272 | ret = -1; | |
1273 | goto failed; | |
1274 | } | |
3d083395 | 1275 | |
d61f82d0 | 1276 | last_ftrace_enabled = ftrace_enabled = 1; |
e1c08bdd | 1277 | ftraced_task = p; |
3d083395 SR |
1278 | |
1279 | return 0; | |
4eebcc81 SR |
1280 | |
1281 | failed: | |
1282 | ftrace_disabled = 1; | |
1283 | return ret; | |
3d083395 SR |
1284 | } |
1285 | ||
d61f82d0 | 1286 | core_initcall(ftrace_dynamic_init); |
3d083395 | 1287 | #else |
c7aafc54 IM |
1288 | # define ftrace_startup() do { } while (0) |
1289 | # define ftrace_shutdown() do { } while (0) | |
1290 | # define ftrace_startup_sysctl() do { } while (0) | |
1291 | # define ftrace_shutdown_sysctl() do { } while (0) | |
4eebcc81 | 1292 | # define ftrace_force_shutdown() do { } while (0) |
3d083395 SR |
1293 | #endif /* CONFIG_DYNAMIC_FTRACE */ |
1294 | ||
4eebcc81 SR |
1295 | /** |
1296 | * ftrace_kill - totally shutdown ftrace | |
1297 | * | |
1298 | * This is a safety measure. If something was detected that seems | |
1299 | * wrong, calling this function will keep ftrace from doing | |
1300 | * any more modifications, and updates. | |
1301 | * used when something went wrong. | |
1302 | */ | |
1303 | void ftrace_kill(void) | |
1304 | { | |
1305 | mutex_lock(&ftrace_sysctl_lock); | |
1306 | ftrace_disabled = 1; | |
1307 | ftrace_enabled = 0; | |
1308 | ||
1309 | clear_ftrace_function(); | |
1310 | mutex_unlock(&ftrace_sysctl_lock); | |
1311 | ||
1312 | /* Try to totally disable ftrace */ | |
1313 | ftrace_force_shutdown(); | |
1314 | } | |
1315 | ||
16444a8a | 1316 | /** |
3d083395 SR |
1317 | * register_ftrace_function - register a function for profiling |
1318 | * @ops - ops structure that holds the function for profiling. | |
16444a8a | 1319 | * |
3d083395 SR |
1320 | * Register a function to be called by all functions in the |
1321 | * kernel. | |
1322 | * | |
1323 | * Note: @ops->func and all the functions it calls must be labeled | |
1324 | * with "notrace", otherwise it will go into a | |
1325 | * recursive loop. | |
16444a8a | 1326 | */ |
3d083395 | 1327 | int register_ftrace_function(struct ftrace_ops *ops) |
16444a8a | 1328 | { |
b0fc494f SR |
1329 | int ret; |
1330 | ||
4eebcc81 SR |
1331 | if (unlikely(ftrace_disabled)) |
1332 | return -1; | |
1333 | ||
b0fc494f | 1334 | mutex_lock(&ftrace_sysctl_lock); |
b0fc494f | 1335 | ret = __register_ftrace_function(ops); |
d61f82d0 | 1336 | ftrace_startup(); |
b0fc494f SR |
1337 | mutex_unlock(&ftrace_sysctl_lock); |
1338 | ||
1339 | return ret; | |
3d083395 SR |
1340 | } |
1341 | ||
1342 | /** | |
1343 | * unregister_ftrace_function - unresgister a function for profiling. | |
1344 | * @ops - ops structure that holds the function to unregister | |
1345 | * | |
1346 | * Unregister a function that was added to be called by ftrace profiling. | |
1347 | */ | |
1348 | int unregister_ftrace_function(struct ftrace_ops *ops) | |
1349 | { | |
1350 | int ret; | |
1351 | ||
b0fc494f | 1352 | mutex_lock(&ftrace_sysctl_lock); |
3d083395 | 1353 | ret = __unregister_ftrace_function(ops); |
d61f82d0 | 1354 | ftrace_shutdown(); |
b0fc494f SR |
1355 | mutex_unlock(&ftrace_sysctl_lock); |
1356 | ||
1357 | return ret; | |
1358 | } | |
1359 | ||
e309b41d | 1360 | int |
b0fc494f | 1361 | ftrace_enable_sysctl(struct ctl_table *table, int write, |
5072c59f | 1362 | struct file *file, void __user *buffer, size_t *lenp, |
b0fc494f SR |
1363 | loff_t *ppos) |
1364 | { | |
1365 | int ret; | |
1366 | ||
4eebcc81 SR |
1367 | if (unlikely(ftrace_disabled)) |
1368 | return -ENODEV; | |
1369 | ||
b0fc494f SR |
1370 | mutex_lock(&ftrace_sysctl_lock); |
1371 | ||
5072c59f | 1372 | ret = proc_dointvec(table, write, file, buffer, lenp, ppos); |
b0fc494f SR |
1373 | |
1374 | if (ret || !write || (last_ftrace_enabled == ftrace_enabled)) | |
1375 | goto out; | |
1376 | ||
1377 | last_ftrace_enabled = ftrace_enabled; | |
1378 | ||
1379 | if (ftrace_enabled) { | |
1380 | ||
1381 | ftrace_startup_sysctl(); | |
1382 | ||
1383 | /* we are starting ftrace again */ | |
1384 | if (ftrace_list != &ftrace_list_end) { | |
1385 | if (ftrace_list->next == &ftrace_list_end) | |
1386 | ftrace_trace_function = ftrace_list->func; | |
1387 | else | |
1388 | ftrace_trace_function = ftrace_list_func; | |
1389 | } | |
1390 | ||
1391 | } else { | |
1392 | /* stopping ftrace calls (just send to ftrace_stub) */ | |
1393 | ftrace_trace_function = ftrace_stub; | |
1394 | ||
1395 | ftrace_shutdown_sysctl(); | |
1396 | } | |
1397 | ||
1398 | out: | |
1399 | mutex_unlock(&ftrace_sysctl_lock); | |
3d083395 | 1400 | return ret; |
16444a8a | 1401 | } |