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 | 21 | #include <linux/hardirq.h> |
2d8b820b | 22 | #include <linux/kthread.h> |
5072c59f | 23 | #include <linux/uaccess.h> |
2d8b820b | 24 | #include <linux/ftrace.h> |
b0fc494f | 25 | #include <linux/sysctl.h> |
5072c59f | 26 | #include <linux/ctype.h> |
2d8b820b | 27 | #include <linux/hash.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 | ||
e309b41d | 53 | void ftrace_list_func(unsigned long ip, unsigned long parent_ip) |
16444a8a ACM |
54 | { |
55 | struct ftrace_ops *op = ftrace_list; | |
56 | ||
57 | /* in case someone actually ports this to alpha! */ | |
58 | read_barrier_depends(); | |
59 | ||
60 | while (op != &ftrace_list_end) { | |
61 | /* silly alpha */ | |
62 | read_barrier_depends(); | |
63 | op->func(ip, parent_ip); | |
64 | op = op->next; | |
65 | }; | |
66 | } | |
67 | ||
68 | /** | |
3d083395 | 69 | * clear_ftrace_function - reset the ftrace function |
16444a8a | 70 | * |
3d083395 SR |
71 | * This NULLs the ftrace function and in essence stops |
72 | * tracing. There may be lag | |
16444a8a | 73 | */ |
3d083395 | 74 | void clear_ftrace_function(void) |
16444a8a | 75 | { |
3d083395 SR |
76 | ftrace_trace_function = ftrace_stub; |
77 | } | |
78 | ||
e309b41d | 79 | static int __register_ftrace_function(struct ftrace_ops *ops) |
3d083395 SR |
80 | { |
81 | /* Should never be called by interrupts */ | |
82 | spin_lock(&ftrace_lock); | |
16444a8a | 83 | |
16444a8a ACM |
84 | ops->next = ftrace_list; |
85 | /* | |
86 | * We are entering ops into the ftrace_list but another | |
87 | * CPU might be walking that list. We need to make sure | |
88 | * the ops->next pointer is valid before another CPU sees | |
89 | * the ops pointer included into the ftrace_list. | |
90 | */ | |
91 | smp_wmb(); | |
92 | ftrace_list = ops; | |
3d083395 | 93 | |
b0fc494f SR |
94 | if (ftrace_enabled) { |
95 | /* | |
96 | * For one func, simply call it directly. | |
97 | * For more than one func, call the chain. | |
98 | */ | |
99 | if (ops->next == &ftrace_list_end) | |
100 | ftrace_trace_function = ops->func; | |
101 | else | |
102 | ftrace_trace_function = ftrace_list_func; | |
103 | } | |
3d083395 SR |
104 | |
105 | spin_unlock(&ftrace_lock); | |
16444a8a ACM |
106 | |
107 | return 0; | |
108 | } | |
109 | ||
e309b41d | 110 | static int __unregister_ftrace_function(struct ftrace_ops *ops) |
16444a8a | 111 | { |
16444a8a ACM |
112 | struct ftrace_ops **p; |
113 | int ret = 0; | |
114 | ||
3d083395 | 115 | spin_lock(&ftrace_lock); |
16444a8a ACM |
116 | |
117 | /* | |
3d083395 SR |
118 | * If we are removing the last function, then simply point |
119 | * to the ftrace_stub. | |
16444a8a ACM |
120 | */ |
121 | if (ftrace_list == ops && ops->next == &ftrace_list_end) { | |
122 | ftrace_trace_function = ftrace_stub; | |
123 | ftrace_list = &ftrace_list_end; | |
124 | goto out; | |
125 | } | |
126 | ||
127 | for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next) | |
128 | if (*p == ops) | |
129 | break; | |
130 | ||
131 | if (*p != ops) { | |
132 | ret = -1; | |
133 | goto out; | |
134 | } | |
135 | ||
136 | *p = (*p)->next; | |
137 | ||
b0fc494f SR |
138 | if (ftrace_enabled) { |
139 | /* If we only have one func left, then call that directly */ | |
140 | if (ftrace_list == &ftrace_list_end || | |
141 | ftrace_list->next == &ftrace_list_end) | |
142 | ftrace_trace_function = ftrace_list->func; | |
143 | } | |
16444a8a ACM |
144 | |
145 | out: | |
3d083395 SR |
146 | spin_unlock(&ftrace_lock); |
147 | ||
148 | return ret; | |
149 | } | |
150 | ||
151 | #ifdef CONFIG_DYNAMIC_FTRACE | |
152 | ||
e1c08bdd SR |
153 | static struct task_struct *ftraced_task; |
154 | static DECLARE_WAIT_QUEUE_HEAD(ftraced_waiters); | |
155 | static unsigned long ftraced_iteration_counter; | |
156 | ||
d61f82d0 SR |
157 | enum { |
158 | FTRACE_ENABLE_CALLS = (1 << 0), | |
159 | FTRACE_DISABLE_CALLS = (1 << 1), | |
160 | FTRACE_UPDATE_TRACE_FUNC = (1 << 2), | |
161 | FTRACE_ENABLE_MCOUNT = (1 << 3), | |
162 | FTRACE_DISABLE_MCOUNT = (1 << 4), | |
163 | }; | |
164 | ||
5072c59f SR |
165 | static int ftrace_filtered; |
166 | ||
3d083395 SR |
167 | static struct hlist_head ftrace_hash[FTRACE_HASHSIZE]; |
168 | ||
169 | static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu); | |
170 | ||
171 | static DEFINE_SPINLOCK(ftrace_shutdown_lock); | |
172 | static DEFINE_MUTEX(ftraced_lock); | |
5072c59f | 173 | static DEFINE_MUTEX(ftrace_filter_lock); |
3d083395 | 174 | |
3c1720f0 SR |
175 | struct ftrace_page { |
176 | struct ftrace_page *next; | |
aa5e5cea | 177 | unsigned long index; |
3c1720f0 | 178 | struct dyn_ftrace records[]; |
aa5e5cea | 179 | }; |
3c1720f0 SR |
180 | |
181 | #define ENTRIES_PER_PAGE \ | |
182 | ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace)) | |
183 | ||
184 | /* estimate from running different kernels */ | |
185 | #define NR_TO_INIT 10000 | |
186 | ||
187 | static struct ftrace_page *ftrace_pages_start; | |
188 | static struct ftrace_page *ftrace_pages; | |
189 | ||
3d083395 SR |
190 | static int ftraced_trigger; |
191 | static int ftraced_suspend; | |
192 | ||
193 | static int ftrace_record_suspend; | |
194 | ||
37ad5084 SR |
195 | static struct dyn_ftrace *ftrace_free_records; |
196 | ||
e309b41d | 197 | static inline int |
9ff9cdb2 | 198 | ftrace_ip_in_hash(unsigned long ip, unsigned long key) |
3d083395 SR |
199 | { |
200 | struct dyn_ftrace *p; | |
201 | struct hlist_node *t; | |
202 | int found = 0; | |
203 | ||
204 | hlist_for_each_entry(p, t, &ftrace_hash[key], node) { | |
205 | if (p->ip == ip) { | |
206 | found = 1; | |
207 | break; | |
208 | } | |
209 | } | |
210 | ||
211 | return found; | |
212 | } | |
213 | ||
e309b41d | 214 | static inline void |
3d083395 SR |
215 | ftrace_add_hash(struct dyn_ftrace *node, unsigned long key) |
216 | { | |
217 | hlist_add_head(&node->node, &ftrace_hash[key]); | |
218 | } | |
219 | ||
e309b41d | 220 | static void ftrace_free_rec(struct dyn_ftrace *rec) |
37ad5084 SR |
221 | { |
222 | /* no locking, only called from kstop_machine */ | |
223 | ||
224 | rec->ip = (unsigned long)ftrace_free_records; | |
225 | ftrace_free_records = rec; | |
226 | rec->flags |= FTRACE_FL_FREE; | |
227 | } | |
228 | ||
e309b41d | 229 | static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip) |
3c1720f0 | 230 | { |
37ad5084 SR |
231 | struct dyn_ftrace *rec; |
232 | ||
233 | /* First check for freed records */ | |
234 | if (ftrace_free_records) { | |
235 | rec = ftrace_free_records; | |
236 | ||
37ad5084 SR |
237 | if (unlikely(!(rec->flags & FTRACE_FL_FREE))) { |
238 | WARN_ON_ONCE(1); | |
239 | ftrace_free_records = NULL; | |
4eebcc81 SR |
240 | ftrace_disabled = 1; |
241 | ftrace_enabled = 0; | |
37ad5084 SR |
242 | return NULL; |
243 | } | |
244 | ||
245 | ftrace_free_records = (void *)rec->ip; | |
246 | memset(rec, 0, sizeof(*rec)); | |
247 | return rec; | |
248 | } | |
249 | ||
3c1720f0 SR |
250 | if (ftrace_pages->index == ENTRIES_PER_PAGE) { |
251 | if (!ftrace_pages->next) | |
252 | return NULL; | |
253 | ftrace_pages = ftrace_pages->next; | |
254 | } | |
255 | ||
256 | return &ftrace_pages->records[ftrace_pages->index++]; | |
257 | } | |
258 | ||
e309b41d | 259 | static void |
d61f82d0 | 260 | ftrace_record_ip(unsigned long ip) |
3d083395 SR |
261 | { |
262 | struct dyn_ftrace *node; | |
263 | unsigned long flags; | |
264 | unsigned long key; | |
265 | int resched; | |
266 | int atomic; | |
2bb6f8d6 | 267 | int cpu; |
3d083395 | 268 | |
4eebcc81 | 269 | if (!ftrace_enabled || ftrace_disabled) |
d61f82d0 SR |
270 | return; |
271 | ||
3d083395 SR |
272 | resched = need_resched(); |
273 | preempt_disable_notrace(); | |
274 | ||
2bb6f8d6 SR |
275 | /* |
276 | * We simply need to protect against recursion. | |
277 | * Use the the raw version of smp_processor_id and not | |
278 | * __get_cpu_var which can call debug hooks that can | |
279 | * cause a recursive crash here. | |
280 | */ | |
281 | cpu = raw_smp_processor_id(); | |
282 | per_cpu(ftrace_shutdown_disable_cpu, cpu)++; | |
283 | if (per_cpu(ftrace_shutdown_disable_cpu, cpu) != 1) | |
3d083395 SR |
284 | goto out; |
285 | ||
286 | if (unlikely(ftrace_record_suspend)) | |
287 | goto out; | |
288 | ||
289 | key = hash_long(ip, FTRACE_HASHBITS); | |
290 | ||
291 | WARN_ON_ONCE(key >= FTRACE_HASHSIZE); | |
292 | ||
293 | if (ftrace_ip_in_hash(ip, key)) | |
294 | goto out; | |
295 | ||
296 | atomic = irqs_disabled(); | |
297 | ||
298 | spin_lock_irqsave(&ftrace_shutdown_lock, flags); | |
299 | ||
300 | /* This ip may have hit the hash before the lock */ | |
301 | if (ftrace_ip_in_hash(ip, key)) | |
302 | goto out_unlock; | |
303 | ||
304 | /* | |
305 | * There's a slight race that the ftraced will update the | |
d61f82d0 | 306 | * hash and reset here. If it is already converted, skip it. |
3d083395 | 307 | */ |
d61f82d0 SR |
308 | if (ftrace_ip_converted(ip)) |
309 | goto out_unlock; | |
310 | ||
311 | node = ftrace_alloc_dyn_node(ip); | |
3d083395 SR |
312 | if (!node) |
313 | goto out_unlock; | |
314 | ||
315 | node->ip = ip; | |
316 | ||
317 | ftrace_add_hash(node, key); | |
318 | ||
319 | ftraced_trigger = 1; | |
320 | ||
321 | out_unlock: | |
322 | spin_unlock_irqrestore(&ftrace_shutdown_lock, flags); | |
323 | out: | |
2bb6f8d6 | 324 | per_cpu(ftrace_shutdown_disable_cpu, cpu)--; |
3d083395 SR |
325 | |
326 | /* prevent recursion with scheduler */ | |
327 | if (resched) | |
328 | preempt_enable_no_resched_notrace(); | |
329 | else | |
330 | preempt_enable_notrace(); | |
331 | } | |
332 | ||
caf8cdeb SR |
333 | #define FTRACE_ADDR ((long)(ftrace_caller)) |
334 | #define MCOUNT_ADDR ((long)(mcount)) | |
3c1720f0 | 335 | |
e309b41d | 336 | static void |
5072c59f SR |
337 | __ftrace_replace_code(struct dyn_ftrace *rec, |
338 | unsigned char *old, unsigned char *new, int enable) | |
339 | { | |
340 | unsigned long ip; | |
341 | int failed; | |
342 | ||
343 | ip = rec->ip; | |
344 | ||
345 | if (ftrace_filtered && enable) { | |
346 | unsigned long fl; | |
347 | /* | |
348 | * If filtering is on: | |
349 | * | |
350 | * If this record is set to be filtered and | |
351 | * is enabled then do nothing. | |
352 | * | |
353 | * If this record is set to be filtered and | |
354 | * it is not enabled, enable it. | |
355 | * | |
356 | * If this record is not set to be filtered | |
357 | * and it is not enabled do nothing. | |
358 | * | |
359 | * If this record is not set to be filtered and | |
360 | * it is enabled, disable it. | |
361 | */ | |
362 | fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED); | |
363 | ||
364 | if ((fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) || | |
365 | (fl == 0)) | |
366 | return; | |
367 | ||
368 | /* | |
369 | * If it is enabled disable it, | |
370 | * otherwise enable it! | |
371 | */ | |
372 | if (fl == FTRACE_FL_ENABLED) { | |
373 | /* swap new and old */ | |
374 | new = old; | |
375 | old = ftrace_call_replace(ip, FTRACE_ADDR); | |
376 | rec->flags &= ~FTRACE_FL_ENABLED; | |
377 | } else { | |
378 | new = ftrace_call_replace(ip, FTRACE_ADDR); | |
379 | rec->flags |= FTRACE_FL_ENABLED; | |
380 | } | |
381 | } else { | |
382 | ||
383 | if (enable) | |
384 | new = ftrace_call_replace(ip, FTRACE_ADDR); | |
385 | else | |
386 | old = ftrace_call_replace(ip, FTRACE_ADDR); | |
387 | ||
388 | if (enable) { | |
389 | if (rec->flags & FTRACE_FL_ENABLED) | |
390 | return; | |
391 | rec->flags |= FTRACE_FL_ENABLED; | |
392 | } else { | |
393 | if (!(rec->flags & FTRACE_FL_ENABLED)) | |
394 | return; | |
395 | rec->flags &= ~FTRACE_FL_ENABLED; | |
396 | } | |
397 | } | |
398 | ||
399 | failed = ftrace_modify_code(ip, old, new); | |
37ad5084 SR |
400 | if (failed) { |
401 | unsigned long key; | |
402 | /* It is possible that the function hasn't been converted yet */ | |
403 | key = hash_long(ip, FTRACE_HASHBITS); | |
404 | if (!ftrace_ip_in_hash(ip, key)) { | |
405 | rec->flags |= FTRACE_FL_FAILED; | |
406 | ftrace_free_rec(rec); | |
407 | } | |
408 | ||
409 | } | |
5072c59f SR |
410 | } |
411 | ||
e309b41d | 412 | static void ftrace_replace_code(int enable) |
3c1720f0 SR |
413 | { |
414 | unsigned char *new = NULL, *old = NULL; | |
415 | struct dyn_ftrace *rec; | |
416 | struct ftrace_page *pg; | |
3c1720f0 SR |
417 | int i; |
418 | ||
5072c59f | 419 | if (enable) |
3c1720f0 SR |
420 | old = ftrace_nop_replace(); |
421 | else | |
422 | new = ftrace_nop_replace(); | |
423 | ||
424 | for (pg = ftrace_pages_start; pg; pg = pg->next) { | |
425 | for (i = 0; i < pg->index; i++) { | |
426 | rec = &pg->records[i]; | |
427 | ||
428 | /* don't modify code that has already faulted */ | |
429 | if (rec->flags & FTRACE_FL_FAILED) | |
430 | continue; | |
431 | ||
5072c59f | 432 | __ftrace_replace_code(rec, old, new, enable); |
3c1720f0 SR |
433 | } |
434 | } | |
435 | } | |
436 | ||
e309b41d | 437 | static void ftrace_shutdown_replenish(void) |
3c1720f0 SR |
438 | { |
439 | if (ftrace_pages->next) | |
440 | return; | |
441 | ||
442 | /* allocate another page */ | |
443 | ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL); | |
444 | } | |
3d083395 | 445 | |
e309b41d | 446 | static void |
d61f82d0 | 447 | ftrace_code_disable(struct dyn_ftrace *rec) |
3c1720f0 SR |
448 | { |
449 | unsigned long ip; | |
450 | unsigned char *nop, *call; | |
451 | int failed; | |
452 | ||
453 | ip = rec->ip; | |
454 | ||
455 | nop = ftrace_nop_replace(); | |
d61f82d0 | 456 | call = ftrace_call_replace(ip, MCOUNT_ADDR); |
3c1720f0 SR |
457 | |
458 | failed = ftrace_modify_code(ip, call, nop); | |
37ad5084 | 459 | if (failed) { |
3c1720f0 | 460 | rec->flags |= FTRACE_FL_FAILED; |
37ad5084 SR |
461 | ftrace_free_rec(rec); |
462 | } | |
3c1720f0 SR |
463 | } |
464 | ||
e309b41d | 465 | static int __ftrace_modify_code(void *data) |
3d083395 | 466 | { |
d61f82d0 SR |
467 | unsigned long addr; |
468 | int *command = data; | |
469 | ||
470 | if (*command & FTRACE_ENABLE_CALLS) | |
471 | ftrace_replace_code(1); | |
472 | else if (*command & FTRACE_DISABLE_CALLS) | |
473 | ftrace_replace_code(0); | |
474 | ||
475 | if (*command & FTRACE_UPDATE_TRACE_FUNC) | |
476 | ftrace_update_ftrace_func(ftrace_trace_function); | |
477 | ||
478 | if (*command & FTRACE_ENABLE_MCOUNT) { | |
479 | addr = (unsigned long)ftrace_record_ip; | |
480 | ftrace_mcount_set(&addr); | |
481 | } else if (*command & FTRACE_DISABLE_MCOUNT) { | |
482 | addr = (unsigned long)ftrace_stub; | |
483 | ftrace_mcount_set(&addr); | |
484 | } | |
485 | ||
486 | return 0; | |
3d083395 SR |
487 | } |
488 | ||
e309b41d | 489 | static void ftrace_run_update_code(int command) |
3d083395 | 490 | { |
d61f82d0 | 491 | stop_machine_run(__ftrace_modify_code, &command, NR_CPUS); |
3d083395 SR |
492 | } |
493 | ||
d61f82d0 SR |
494 | static ftrace_func_t saved_ftrace_func; |
495 | ||
e309b41d | 496 | static void ftrace_startup(void) |
3d083395 | 497 | { |
d61f82d0 SR |
498 | int command = 0; |
499 | ||
4eebcc81 SR |
500 | if (unlikely(ftrace_disabled)) |
501 | return; | |
502 | ||
3d083395 SR |
503 | mutex_lock(&ftraced_lock); |
504 | ftraced_suspend++; | |
d61f82d0 SR |
505 | if (ftraced_suspend == 1) |
506 | command |= FTRACE_ENABLE_CALLS; | |
507 | ||
508 | if (saved_ftrace_func != ftrace_trace_function) { | |
509 | saved_ftrace_func = ftrace_trace_function; | |
510 | command |= FTRACE_UPDATE_TRACE_FUNC; | |
511 | } | |
512 | ||
513 | if (!command || !ftrace_enabled) | |
3d083395 | 514 | goto out; |
3d083395 | 515 | |
d61f82d0 | 516 | ftrace_run_update_code(command); |
3d083395 SR |
517 | out: |
518 | mutex_unlock(&ftraced_lock); | |
519 | } | |
520 | ||
e309b41d | 521 | static void ftrace_shutdown(void) |
3d083395 | 522 | { |
d61f82d0 SR |
523 | int command = 0; |
524 | ||
4eebcc81 SR |
525 | if (unlikely(ftrace_disabled)) |
526 | return; | |
527 | ||
3d083395 SR |
528 | mutex_lock(&ftraced_lock); |
529 | ftraced_suspend--; | |
d61f82d0 SR |
530 | if (!ftraced_suspend) |
531 | command |= FTRACE_DISABLE_CALLS; | |
3d083395 | 532 | |
d61f82d0 SR |
533 | if (saved_ftrace_func != ftrace_trace_function) { |
534 | saved_ftrace_func = ftrace_trace_function; | |
535 | command |= FTRACE_UPDATE_TRACE_FUNC; | |
536 | } | |
3d083395 | 537 | |
d61f82d0 SR |
538 | if (!command || !ftrace_enabled) |
539 | goto out; | |
540 | ||
541 | ftrace_run_update_code(command); | |
3d083395 SR |
542 | out: |
543 | mutex_unlock(&ftraced_lock); | |
544 | } | |
545 | ||
e309b41d | 546 | static void ftrace_startup_sysctl(void) |
b0fc494f | 547 | { |
d61f82d0 SR |
548 | int command = FTRACE_ENABLE_MCOUNT; |
549 | ||
4eebcc81 SR |
550 | if (unlikely(ftrace_disabled)) |
551 | return; | |
552 | ||
b0fc494f | 553 | mutex_lock(&ftraced_lock); |
d61f82d0 SR |
554 | /* Force update next time */ |
555 | saved_ftrace_func = NULL; | |
b0fc494f SR |
556 | /* ftraced_suspend is true if we want ftrace running */ |
557 | if (ftraced_suspend) | |
d61f82d0 SR |
558 | command |= FTRACE_ENABLE_CALLS; |
559 | ||
560 | ftrace_run_update_code(command); | |
b0fc494f SR |
561 | mutex_unlock(&ftraced_lock); |
562 | } | |
563 | ||
e309b41d | 564 | static void ftrace_shutdown_sysctl(void) |
b0fc494f | 565 | { |
d61f82d0 SR |
566 | int command = FTRACE_DISABLE_MCOUNT; |
567 | ||
4eebcc81 SR |
568 | if (unlikely(ftrace_disabled)) |
569 | return; | |
570 | ||
b0fc494f SR |
571 | mutex_lock(&ftraced_lock); |
572 | /* ftraced_suspend is true if ftrace is running */ | |
573 | if (ftraced_suspend) | |
d61f82d0 SR |
574 | command |= FTRACE_DISABLE_CALLS; |
575 | ||
576 | ftrace_run_update_code(command); | |
b0fc494f SR |
577 | mutex_unlock(&ftraced_lock); |
578 | } | |
579 | ||
3d083395 SR |
580 | static cycle_t ftrace_update_time; |
581 | static unsigned long ftrace_update_cnt; | |
582 | unsigned long ftrace_update_tot_cnt; | |
583 | ||
e309b41d | 584 | static int __ftrace_update_code(void *ignore) |
3d083395 SR |
585 | { |
586 | struct dyn_ftrace *p; | |
587 | struct hlist_head head; | |
588 | struct hlist_node *t; | |
d61f82d0 | 589 | int save_ftrace_enabled; |
3d083395 SR |
590 | cycle_t start, stop; |
591 | int i; | |
592 | ||
d61f82d0 SR |
593 | /* Don't be recording funcs now */ |
594 | save_ftrace_enabled = ftrace_enabled; | |
595 | ftrace_enabled = 0; | |
3d083395 | 596 | |
750ed1a4 | 597 | start = ftrace_now(raw_smp_processor_id()); |
3d083395 SR |
598 | ftrace_update_cnt = 0; |
599 | ||
600 | /* No locks needed, the machine is stopped! */ | |
601 | for (i = 0; i < FTRACE_HASHSIZE; i++) { | |
602 | if (hlist_empty(&ftrace_hash[i])) | |
603 | continue; | |
604 | ||
605 | head = ftrace_hash[i]; | |
606 | INIT_HLIST_HEAD(&ftrace_hash[i]); | |
607 | ||
608 | /* all CPUS are stopped, we are safe to modify code */ | |
609 | hlist_for_each_entry(p, t, &head, node) { | |
d61f82d0 | 610 | ftrace_code_disable(p); |
3d083395 SR |
611 | ftrace_update_cnt++; |
612 | } | |
613 | ||
614 | } | |
615 | ||
750ed1a4 | 616 | stop = ftrace_now(raw_smp_processor_id()); |
3d083395 SR |
617 | ftrace_update_time = stop - start; |
618 | ftrace_update_tot_cnt += ftrace_update_cnt; | |
619 | ||
d61f82d0 | 620 | ftrace_enabled = save_ftrace_enabled; |
16444a8a ACM |
621 | |
622 | return 0; | |
623 | } | |
624 | ||
e309b41d | 625 | static void ftrace_update_code(void) |
3d083395 | 626 | { |
4eebcc81 SR |
627 | if (unlikely(ftrace_disabled)) |
628 | return; | |
629 | ||
3d083395 SR |
630 | stop_machine_run(__ftrace_update_code, NULL, NR_CPUS); |
631 | } | |
632 | ||
e309b41d | 633 | static int ftraced(void *ignore) |
3d083395 SR |
634 | { |
635 | unsigned long usecs; | |
636 | ||
3d083395 SR |
637 | while (!kthread_should_stop()) { |
638 | ||
07a267cd SR |
639 | set_current_state(TASK_INTERRUPTIBLE); |
640 | ||
3d083395 SR |
641 | /* check once a second */ |
642 | schedule_timeout(HZ); | |
643 | ||
4eebcc81 SR |
644 | if (unlikely(ftrace_disabled)) |
645 | continue; | |
646 | ||
b0fc494f | 647 | mutex_lock(&ftrace_sysctl_lock); |
3d083395 | 648 | mutex_lock(&ftraced_lock); |
b0fc494f | 649 | if (ftrace_enabled && ftraced_trigger && !ftraced_suspend) { |
3d083395 SR |
650 | ftrace_record_suspend++; |
651 | ftrace_update_code(); | |
652 | usecs = nsecs_to_usecs(ftrace_update_time); | |
653 | if (ftrace_update_tot_cnt > 100000) { | |
654 | ftrace_update_tot_cnt = 0; | |
655 | pr_info("hm, dftrace overflow: %lu change%s" | |
656 | " (%lu total) in %lu usec%s\n", | |
657 | ftrace_update_cnt, | |
658 | ftrace_update_cnt != 1 ? "s" : "", | |
659 | ftrace_update_tot_cnt, | |
660 | usecs, usecs != 1 ? "s" : ""); | |
4eebcc81 | 661 | ftrace_disabled = 1; |
3d083395 SR |
662 | WARN_ON_ONCE(1); |
663 | } | |
664 | ftraced_trigger = 0; | |
665 | ftrace_record_suspend--; | |
666 | } | |
e1c08bdd | 667 | ftraced_iteration_counter++; |
3d083395 | 668 | mutex_unlock(&ftraced_lock); |
b0fc494f | 669 | mutex_unlock(&ftrace_sysctl_lock); |
3d083395 | 670 | |
e1c08bdd SR |
671 | wake_up_interruptible(&ftraced_waiters); |
672 | ||
3d083395 | 673 | ftrace_shutdown_replenish(); |
3d083395 SR |
674 | } |
675 | __set_current_state(TASK_RUNNING); | |
676 | return 0; | |
677 | } | |
678 | ||
3c1720f0 SR |
679 | static int __init ftrace_dyn_table_alloc(void) |
680 | { | |
681 | struct ftrace_page *pg; | |
682 | int cnt; | |
683 | int i; | |
3c1720f0 SR |
684 | |
685 | /* allocate a few pages */ | |
686 | ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL); | |
687 | if (!ftrace_pages_start) | |
688 | return -1; | |
689 | ||
690 | /* | |
691 | * Allocate a few more pages. | |
692 | * | |
693 | * TODO: have some parser search vmlinux before | |
694 | * final linking to find all calls to ftrace. | |
695 | * Then we can: | |
696 | * a) know how many pages to allocate. | |
697 | * and/or | |
698 | * b) set up the table then. | |
699 | * | |
700 | * The dynamic code is still necessary for | |
701 | * modules. | |
702 | */ | |
703 | ||
704 | pg = ftrace_pages = ftrace_pages_start; | |
705 | ||
706 | cnt = NR_TO_INIT / ENTRIES_PER_PAGE; | |
707 | ||
708 | for (i = 0; i < cnt; i++) { | |
709 | pg->next = (void *)get_zeroed_page(GFP_KERNEL); | |
710 | ||
711 | /* If we fail, we'll try later anyway */ | |
712 | if (!pg->next) | |
713 | break; | |
714 | ||
715 | pg = pg->next; | |
716 | } | |
717 | ||
718 | return 0; | |
719 | } | |
720 | ||
5072c59f SR |
721 | enum { |
722 | FTRACE_ITER_FILTER = (1 << 0), | |
723 | FTRACE_ITER_CONT = (1 << 1), | |
724 | }; | |
725 | ||
726 | #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */ | |
727 | ||
728 | struct ftrace_iterator { | |
729 | loff_t pos; | |
730 | struct ftrace_page *pg; | |
731 | unsigned idx; | |
732 | unsigned flags; | |
733 | unsigned char buffer[FTRACE_BUFF_MAX+1]; | |
734 | unsigned buffer_idx; | |
735 | unsigned filtered; | |
736 | }; | |
737 | ||
e309b41d | 738 | static void * |
5072c59f SR |
739 | t_next(struct seq_file *m, void *v, loff_t *pos) |
740 | { | |
741 | struct ftrace_iterator *iter = m->private; | |
742 | struct dyn_ftrace *rec = NULL; | |
743 | ||
744 | (*pos)++; | |
745 | ||
746 | retry: | |
747 | if (iter->idx >= iter->pg->index) { | |
748 | if (iter->pg->next) { | |
749 | iter->pg = iter->pg->next; | |
750 | iter->idx = 0; | |
751 | goto retry; | |
752 | } | |
753 | } else { | |
754 | rec = &iter->pg->records[iter->idx++]; | |
755 | if ((rec->flags & FTRACE_FL_FAILED) || | |
756 | ((iter->flags & FTRACE_ITER_FILTER) && | |
757 | !(rec->flags & FTRACE_FL_FILTER))) { | |
758 | rec = NULL; | |
759 | goto retry; | |
760 | } | |
761 | } | |
762 | ||
763 | iter->pos = *pos; | |
764 | ||
765 | return rec; | |
766 | } | |
767 | ||
768 | static void *t_start(struct seq_file *m, loff_t *pos) | |
769 | { | |
770 | struct ftrace_iterator *iter = m->private; | |
771 | void *p = NULL; | |
772 | loff_t l = -1; | |
773 | ||
774 | if (*pos != iter->pos) { | |
775 | for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l)) | |
776 | ; | |
777 | } else { | |
778 | l = *pos; | |
779 | p = t_next(m, p, &l); | |
780 | } | |
781 | ||
782 | return p; | |
783 | } | |
784 | ||
785 | static void t_stop(struct seq_file *m, void *p) | |
786 | { | |
787 | } | |
788 | ||
789 | static int t_show(struct seq_file *m, void *v) | |
790 | { | |
791 | struct dyn_ftrace *rec = v; | |
792 | char str[KSYM_SYMBOL_LEN]; | |
793 | ||
794 | if (!rec) | |
795 | return 0; | |
796 | ||
797 | kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); | |
798 | ||
799 | seq_printf(m, "%s\n", str); | |
800 | ||
801 | return 0; | |
802 | } | |
803 | ||
804 | static struct seq_operations show_ftrace_seq_ops = { | |
805 | .start = t_start, | |
806 | .next = t_next, | |
807 | .stop = t_stop, | |
808 | .show = t_show, | |
809 | }; | |
810 | ||
e309b41d | 811 | static int |
5072c59f SR |
812 | ftrace_avail_open(struct inode *inode, struct file *file) |
813 | { | |
814 | struct ftrace_iterator *iter; | |
815 | int ret; | |
816 | ||
4eebcc81 SR |
817 | if (unlikely(ftrace_disabled)) |
818 | return -ENODEV; | |
819 | ||
5072c59f SR |
820 | iter = kzalloc(sizeof(*iter), GFP_KERNEL); |
821 | if (!iter) | |
822 | return -ENOMEM; | |
823 | ||
824 | iter->pg = ftrace_pages_start; | |
825 | iter->pos = -1; | |
826 | ||
827 | ret = seq_open(file, &show_ftrace_seq_ops); | |
828 | if (!ret) { | |
829 | struct seq_file *m = file->private_data; | |
4bf39a94 | 830 | |
5072c59f | 831 | m->private = iter; |
4bf39a94 | 832 | } else { |
5072c59f | 833 | kfree(iter); |
4bf39a94 | 834 | } |
5072c59f SR |
835 | |
836 | return ret; | |
837 | } | |
838 | ||
839 | int ftrace_avail_release(struct inode *inode, struct file *file) | |
840 | { | |
841 | struct seq_file *m = (struct seq_file *)file->private_data; | |
842 | struct ftrace_iterator *iter = m->private; | |
843 | ||
844 | seq_release(inode, file); | |
845 | kfree(iter); | |
4bf39a94 | 846 | |
5072c59f SR |
847 | return 0; |
848 | } | |
849 | ||
e309b41d | 850 | static void ftrace_filter_reset(void) |
5072c59f SR |
851 | { |
852 | struct ftrace_page *pg; | |
853 | struct dyn_ftrace *rec; | |
854 | unsigned i; | |
855 | ||
856 | /* keep kstop machine from running */ | |
857 | preempt_disable(); | |
858 | ftrace_filtered = 0; | |
859 | pg = ftrace_pages_start; | |
860 | while (pg) { | |
861 | for (i = 0; i < pg->index; i++) { | |
862 | rec = &pg->records[i]; | |
863 | if (rec->flags & FTRACE_FL_FAILED) | |
864 | continue; | |
865 | rec->flags &= ~FTRACE_FL_FILTER; | |
866 | } | |
867 | pg = pg->next; | |
868 | } | |
869 | preempt_enable(); | |
870 | } | |
871 | ||
e309b41d | 872 | static int |
5072c59f SR |
873 | ftrace_filter_open(struct inode *inode, struct file *file) |
874 | { | |
875 | struct ftrace_iterator *iter; | |
876 | int ret = 0; | |
877 | ||
4eebcc81 SR |
878 | if (unlikely(ftrace_disabled)) |
879 | return -ENODEV; | |
880 | ||
5072c59f SR |
881 | iter = kzalloc(sizeof(*iter), GFP_KERNEL); |
882 | if (!iter) | |
883 | return -ENOMEM; | |
884 | ||
885 | mutex_lock(&ftrace_filter_lock); | |
886 | if ((file->f_mode & FMODE_WRITE) && | |
887 | !(file->f_flags & O_APPEND)) | |
888 | ftrace_filter_reset(); | |
889 | ||
890 | if (file->f_mode & FMODE_READ) { | |
891 | iter->pg = ftrace_pages_start; | |
892 | iter->pos = -1; | |
893 | iter->flags = FTRACE_ITER_FILTER; | |
894 | ||
895 | ret = seq_open(file, &show_ftrace_seq_ops); | |
896 | if (!ret) { | |
897 | struct seq_file *m = file->private_data; | |
898 | m->private = iter; | |
899 | } else | |
900 | kfree(iter); | |
901 | } else | |
902 | file->private_data = iter; | |
903 | mutex_unlock(&ftrace_filter_lock); | |
904 | ||
905 | return ret; | |
906 | } | |
907 | ||
e309b41d | 908 | static ssize_t |
5072c59f SR |
909 | ftrace_filter_read(struct file *file, char __user *ubuf, |
910 | size_t cnt, loff_t *ppos) | |
911 | { | |
912 | if (file->f_mode & FMODE_READ) | |
913 | return seq_read(file, ubuf, cnt, ppos); | |
914 | else | |
915 | return -EPERM; | |
916 | } | |
917 | ||
e309b41d | 918 | static loff_t |
5072c59f SR |
919 | ftrace_filter_lseek(struct file *file, loff_t offset, int origin) |
920 | { | |
921 | loff_t ret; | |
922 | ||
923 | if (file->f_mode & FMODE_READ) | |
924 | ret = seq_lseek(file, offset, origin); | |
925 | else | |
926 | file->f_pos = ret = 1; | |
927 | ||
928 | return ret; | |
929 | } | |
930 | ||
931 | enum { | |
932 | MATCH_FULL, | |
933 | MATCH_FRONT_ONLY, | |
934 | MATCH_MIDDLE_ONLY, | |
935 | MATCH_END_ONLY, | |
936 | }; | |
937 | ||
e309b41d | 938 | static void |
5072c59f SR |
939 | ftrace_match(unsigned char *buff, int len) |
940 | { | |
941 | char str[KSYM_SYMBOL_LEN]; | |
942 | char *search = NULL; | |
943 | struct ftrace_page *pg; | |
944 | struct dyn_ftrace *rec; | |
945 | int type = MATCH_FULL; | |
946 | unsigned i, match = 0, search_len = 0; | |
947 | ||
948 | for (i = 0; i < len; i++) { | |
949 | if (buff[i] == '*') { | |
950 | if (!i) { | |
951 | search = buff + i + 1; | |
952 | type = MATCH_END_ONLY; | |
953 | search_len = len - (i + 1); | |
954 | } else { | |
955 | if (type == MATCH_END_ONLY) { | |
956 | type = MATCH_MIDDLE_ONLY; | |
957 | } else { | |
958 | match = i; | |
959 | type = MATCH_FRONT_ONLY; | |
960 | } | |
961 | buff[i] = 0; | |
962 | break; | |
963 | } | |
964 | } | |
965 | } | |
966 | ||
967 | /* keep kstop machine from running */ | |
968 | preempt_disable(); | |
969 | ftrace_filtered = 1; | |
970 | pg = ftrace_pages_start; | |
971 | while (pg) { | |
972 | for (i = 0; i < pg->index; i++) { | |
973 | int matched = 0; | |
974 | char *ptr; | |
975 | ||
976 | rec = &pg->records[i]; | |
977 | if (rec->flags & FTRACE_FL_FAILED) | |
978 | continue; | |
979 | kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); | |
980 | switch (type) { | |
981 | case MATCH_FULL: | |
982 | if (strcmp(str, buff) == 0) | |
983 | matched = 1; | |
984 | break; | |
985 | case MATCH_FRONT_ONLY: | |
986 | if (memcmp(str, buff, match) == 0) | |
987 | matched = 1; | |
988 | break; | |
989 | case MATCH_MIDDLE_ONLY: | |
990 | if (strstr(str, search)) | |
991 | matched = 1; | |
992 | break; | |
993 | case MATCH_END_ONLY: | |
994 | ptr = strstr(str, search); | |
995 | if (ptr && (ptr[search_len] == 0)) | |
996 | matched = 1; | |
997 | break; | |
998 | } | |
999 | if (matched) | |
1000 | rec->flags |= FTRACE_FL_FILTER; | |
1001 | } | |
1002 | pg = pg->next; | |
1003 | } | |
1004 | preempt_enable(); | |
1005 | } | |
1006 | ||
e309b41d | 1007 | static ssize_t |
5072c59f SR |
1008 | ftrace_filter_write(struct file *file, const char __user *ubuf, |
1009 | size_t cnt, loff_t *ppos) | |
1010 | { | |
1011 | struct ftrace_iterator *iter; | |
1012 | char ch; | |
1013 | size_t read = 0; | |
1014 | ssize_t ret; | |
1015 | ||
1016 | if (!cnt || cnt < 0) | |
1017 | return 0; | |
1018 | ||
1019 | mutex_lock(&ftrace_filter_lock); | |
1020 | ||
1021 | if (file->f_mode & FMODE_READ) { | |
1022 | struct seq_file *m = file->private_data; | |
1023 | iter = m->private; | |
1024 | } else | |
1025 | iter = file->private_data; | |
1026 | ||
1027 | if (!*ppos) { | |
1028 | iter->flags &= ~FTRACE_ITER_CONT; | |
1029 | iter->buffer_idx = 0; | |
1030 | } | |
1031 | ||
1032 | ret = get_user(ch, ubuf++); | |
1033 | if (ret) | |
1034 | goto out; | |
1035 | read++; | |
1036 | cnt--; | |
1037 | ||
1038 | if (!(iter->flags & ~FTRACE_ITER_CONT)) { | |
1039 | /* skip white space */ | |
1040 | while (cnt && isspace(ch)) { | |
1041 | ret = get_user(ch, ubuf++); | |
1042 | if (ret) | |
1043 | goto out; | |
1044 | read++; | |
1045 | cnt--; | |
1046 | } | |
1047 | ||
1048 | ||
1049 | if (isspace(ch)) { | |
1050 | file->f_pos += read; | |
1051 | ret = read; | |
1052 | goto out; | |
1053 | } | |
1054 | ||
1055 | iter->buffer_idx = 0; | |
1056 | } | |
1057 | ||
1058 | while (cnt && !isspace(ch)) { | |
1059 | if (iter->buffer_idx < FTRACE_BUFF_MAX) | |
1060 | iter->buffer[iter->buffer_idx++] = ch; | |
1061 | else { | |
1062 | ret = -EINVAL; | |
1063 | goto out; | |
1064 | } | |
1065 | ret = get_user(ch, ubuf++); | |
1066 | if (ret) | |
1067 | goto out; | |
1068 | read++; | |
1069 | cnt--; | |
1070 | } | |
1071 | ||
1072 | if (isspace(ch)) { | |
1073 | iter->filtered++; | |
1074 | iter->buffer[iter->buffer_idx] = 0; | |
1075 | ftrace_match(iter->buffer, iter->buffer_idx); | |
1076 | iter->buffer_idx = 0; | |
1077 | } else | |
1078 | iter->flags |= FTRACE_ITER_CONT; | |
1079 | ||
1080 | ||
1081 | file->f_pos += read; | |
1082 | ||
1083 | ret = read; | |
1084 | out: | |
1085 | mutex_unlock(&ftrace_filter_lock); | |
1086 | ||
1087 | return ret; | |
1088 | } | |
1089 | ||
77a2b37d SR |
1090 | /** |
1091 | * ftrace_set_filter - set a function to filter on in ftrace | |
1092 | * @buf - the string that holds the function filter text. | |
1093 | * @len - the length of the string. | |
1094 | * @reset - non zero to reset all filters before applying this filter. | |
1095 | * | |
1096 | * Filters denote which functions should be enabled when tracing is enabled. | |
1097 | * If @buf is NULL and reset is set, all functions will be enabled for tracing. | |
1098 | */ | |
e309b41d | 1099 | void ftrace_set_filter(unsigned char *buf, int len, int reset) |
77a2b37d | 1100 | { |
4eebcc81 SR |
1101 | if (unlikely(ftrace_disabled)) |
1102 | return; | |
1103 | ||
77a2b37d SR |
1104 | mutex_lock(&ftrace_filter_lock); |
1105 | if (reset) | |
1106 | ftrace_filter_reset(); | |
1107 | if (buf) | |
1108 | ftrace_match(buf, len); | |
1109 | mutex_unlock(&ftrace_filter_lock); | |
1110 | } | |
1111 | ||
e309b41d | 1112 | static int |
5072c59f SR |
1113 | ftrace_filter_release(struct inode *inode, struct file *file) |
1114 | { | |
1115 | struct seq_file *m = (struct seq_file *)file->private_data; | |
1116 | struct ftrace_iterator *iter; | |
1117 | ||
1118 | mutex_lock(&ftrace_filter_lock); | |
1119 | if (file->f_mode & FMODE_READ) { | |
1120 | iter = m->private; | |
1121 | ||
1122 | seq_release(inode, file); | |
1123 | } else | |
1124 | iter = file->private_data; | |
1125 | ||
1126 | if (iter->buffer_idx) { | |
1127 | iter->filtered++; | |
1128 | iter->buffer[iter->buffer_idx] = 0; | |
1129 | ftrace_match(iter->buffer, iter->buffer_idx); | |
1130 | } | |
1131 | ||
1132 | mutex_lock(&ftrace_sysctl_lock); | |
1133 | mutex_lock(&ftraced_lock); | |
1134 | if (iter->filtered && ftraced_suspend && ftrace_enabled) | |
1135 | ftrace_run_update_code(FTRACE_ENABLE_CALLS); | |
1136 | mutex_unlock(&ftraced_lock); | |
1137 | mutex_unlock(&ftrace_sysctl_lock); | |
1138 | ||
1139 | kfree(iter); | |
1140 | mutex_unlock(&ftrace_filter_lock); | |
1141 | return 0; | |
1142 | } | |
1143 | ||
1144 | static struct file_operations ftrace_avail_fops = { | |
1145 | .open = ftrace_avail_open, | |
1146 | .read = seq_read, | |
1147 | .llseek = seq_lseek, | |
1148 | .release = ftrace_avail_release, | |
1149 | }; | |
1150 | ||
1151 | static struct file_operations ftrace_filter_fops = { | |
1152 | .open = ftrace_filter_open, | |
1153 | .read = ftrace_filter_read, | |
1154 | .write = ftrace_filter_write, | |
1155 | .llseek = ftrace_filter_lseek, | |
1156 | .release = ftrace_filter_release, | |
1157 | }; | |
1158 | ||
e1c08bdd SR |
1159 | /** |
1160 | * ftrace_force_update - force an update to all recording ftrace functions | |
1161 | * | |
1162 | * The ftrace dynamic update daemon only wakes up once a second. | |
1163 | * There may be cases where an update needs to be done immediately | |
1164 | * for tests or internal kernel tracing to begin. This function | |
1165 | * wakes the daemon to do an update and will not return until the | |
1166 | * update is complete. | |
1167 | */ | |
1168 | int ftrace_force_update(void) | |
1169 | { | |
1170 | unsigned long last_counter; | |
1171 | DECLARE_WAITQUEUE(wait, current); | |
1172 | int ret = 0; | |
1173 | ||
4eebcc81 | 1174 | if (unlikely(ftrace_disabled)) |
e1c08bdd SR |
1175 | return -ENODEV; |
1176 | ||
1177 | mutex_lock(&ftraced_lock); | |
1178 | last_counter = ftraced_iteration_counter; | |
1179 | ||
1180 | set_current_state(TASK_INTERRUPTIBLE); | |
1181 | add_wait_queue(&ftraced_waiters, &wait); | |
1182 | ||
4eebcc81 SR |
1183 | if (unlikely(!ftraced_task)) { |
1184 | ret = -ENODEV; | |
1185 | goto out; | |
1186 | } | |
1187 | ||
e1c08bdd SR |
1188 | do { |
1189 | mutex_unlock(&ftraced_lock); | |
1190 | wake_up_process(ftraced_task); | |
1191 | schedule(); | |
1192 | mutex_lock(&ftraced_lock); | |
1193 | if (signal_pending(current)) { | |
1194 | ret = -EINTR; | |
1195 | break; | |
1196 | } | |
1197 | set_current_state(TASK_INTERRUPTIBLE); | |
1198 | } while (last_counter == ftraced_iteration_counter); | |
1199 | ||
4eebcc81 | 1200 | out: |
e1c08bdd SR |
1201 | mutex_unlock(&ftraced_lock); |
1202 | remove_wait_queue(&ftraced_waiters, &wait); | |
1203 | set_current_state(TASK_RUNNING); | |
1204 | ||
1205 | return ret; | |
1206 | } | |
1207 | ||
4eebcc81 SR |
1208 | static void ftrace_force_shutdown(void) |
1209 | { | |
1210 | struct task_struct *task; | |
1211 | int command = FTRACE_DISABLE_CALLS | FTRACE_UPDATE_TRACE_FUNC; | |
1212 | ||
1213 | mutex_lock(&ftraced_lock); | |
1214 | task = ftraced_task; | |
1215 | ftraced_task = NULL; | |
1216 | ftraced_suspend = -1; | |
1217 | ftrace_run_update_code(command); | |
1218 | mutex_unlock(&ftraced_lock); | |
1219 | ||
1220 | if (task) | |
1221 | kthread_stop(task); | |
1222 | } | |
1223 | ||
5072c59f SR |
1224 | static __init int ftrace_init_debugfs(void) |
1225 | { | |
1226 | struct dentry *d_tracer; | |
1227 | struct dentry *entry; | |
1228 | ||
1229 | d_tracer = tracing_init_dentry(); | |
1230 | ||
1231 | entry = debugfs_create_file("available_filter_functions", 0444, | |
1232 | d_tracer, NULL, &ftrace_avail_fops); | |
1233 | if (!entry) | |
1234 | pr_warning("Could not create debugfs " | |
1235 | "'available_filter_functions' entry\n"); | |
1236 | ||
1237 | entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer, | |
1238 | NULL, &ftrace_filter_fops); | |
1239 | if (!entry) | |
1240 | pr_warning("Could not create debugfs " | |
1241 | "'set_ftrace_filter' entry\n"); | |
1242 | return 0; | |
1243 | } | |
1244 | ||
1245 | fs_initcall(ftrace_init_debugfs); | |
1246 | ||
e309b41d | 1247 | static int __init ftrace_dynamic_init(void) |
3d083395 SR |
1248 | { |
1249 | struct task_struct *p; | |
d61f82d0 | 1250 | unsigned long addr; |
3d083395 SR |
1251 | int ret; |
1252 | ||
d61f82d0 | 1253 | addr = (unsigned long)ftrace_record_ip; |
9ff9cdb2 | 1254 | |
d61f82d0 SR |
1255 | stop_machine_run(ftrace_dyn_arch_init, &addr, NR_CPUS); |
1256 | ||
1257 | /* ftrace_dyn_arch_init places the return code in addr */ | |
4eebcc81 SR |
1258 | if (addr) { |
1259 | ret = (int)addr; | |
1260 | goto failed; | |
1261 | } | |
d61f82d0 | 1262 | |
3c1720f0 | 1263 | ret = ftrace_dyn_table_alloc(); |
3d083395 | 1264 | if (ret) |
4eebcc81 | 1265 | goto failed; |
3d083395 SR |
1266 | |
1267 | p = kthread_run(ftraced, NULL, "ftraced"); | |
4eebcc81 SR |
1268 | if (IS_ERR(p)) { |
1269 | ret = -1; | |
1270 | goto failed; | |
1271 | } | |
3d083395 | 1272 | |
d61f82d0 | 1273 | last_ftrace_enabled = ftrace_enabled = 1; |
e1c08bdd | 1274 | ftraced_task = p; |
3d083395 SR |
1275 | |
1276 | return 0; | |
4eebcc81 SR |
1277 | |
1278 | failed: | |
1279 | ftrace_disabled = 1; | |
1280 | return ret; | |
3d083395 SR |
1281 | } |
1282 | ||
d61f82d0 | 1283 | core_initcall(ftrace_dynamic_init); |
3d083395 | 1284 | #else |
c7aafc54 IM |
1285 | # define ftrace_startup() do { } while (0) |
1286 | # define ftrace_shutdown() do { } while (0) | |
1287 | # define ftrace_startup_sysctl() do { } while (0) | |
1288 | # define ftrace_shutdown_sysctl() do { } while (0) | |
4eebcc81 | 1289 | # define ftrace_force_shutdown() do { } while (0) |
3d083395 SR |
1290 | #endif /* CONFIG_DYNAMIC_FTRACE */ |
1291 | ||
4eebcc81 SR |
1292 | /** |
1293 | * ftrace_kill - totally shutdown ftrace | |
1294 | * | |
1295 | * This is a safety measure. If something was detected that seems | |
1296 | * wrong, calling this function will keep ftrace from doing | |
1297 | * any more modifications, and updates. | |
1298 | * used when something went wrong. | |
1299 | */ | |
1300 | void ftrace_kill(void) | |
1301 | { | |
1302 | mutex_lock(&ftrace_sysctl_lock); | |
1303 | ftrace_disabled = 1; | |
1304 | ftrace_enabled = 0; | |
1305 | ||
1306 | clear_ftrace_function(); | |
1307 | mutex_unlock(&ftrace_sysctl_lock); | |
1308 | ||
1309 | /* Try to totally disable ftrace */ | |
1310 | ftrace_force_shutdown(); | |
1311 | } | |
1312 | ||
16444a8a | 1313 | /** |
3d083395 SR |
1314 | * register_ftrace_function - register a function for profiling |
1315 | * @ops - ops structure that holds the function for profiling. | |
16444a8a | 1316 | * |
3d083395 SR |
1317 | * Register a function to be called by all functions in the |
1318 | * kernel. | |
1319 | * | |
1320 | * Note: @ops->func and all the functions it calls must be labeled | |
1321 | * with "notrace", otherwise it will go into a | |
1322 | * recursive loop. | |
16444a8a | 1323 | */ |
3d083395 | 1324 | int register_ftrace_function(struct ftrace_ops *ops) |
16444a8a | 1325 | { |
b0fc494f SR |
1326 | int ret; |
1327 | ||
4eebcc81 SR |
1328 | if (unlikely(ftrace_disabled)) |
1329 | return -1; | |
1330 | ||
b0fc494f | 1331 | mutex_lock(&ftrace_sysctl_lock); |
b0fc494f | 1332 | ret = __register_ftrace_function(ops); |
d61f82d0 | 1333 | ftrace_startup(); |
b0fc494f SR |
1334 | mutex_unlock(&ftrace_sysctl_lock); |
1335 | ||
1336 | return ret; | |
3d083395 SR |
1337 | } |
1338 | ||
1339 | /** | |
1340 | * unregister_ftrace_function - unresgister a function for profiling. | |
1341 | * @ops - ops structure that holds the function to unregister | |
1342 | * | |
1343 | * Unregister a function that was added to be called by ftrace profiling. | |
1344 | */ | |
1345 | int unregister_ftrace_function(struct ftrace_ops *ops) | |
1346 | { | |
1347 | int ret; | |
1348 | ||
b0fc494f | 1349 | mutex_lock(&ftrace_sysctl_lock); |
3d083395 | 1350 | ret = __unregister_ftrace_function(ops); |
d61f82d0 | 1351 | ftrace_shutdown(); |
b0fc494f SR |
1352 | mutex_unlock(&ftrace_sysctl_lock); |
1353 | ||
1354 | return ret; | |
1355 | } | |
1356 | ||
e309b41d | 1357 | int |
b0fc494f | 1358 | ftrace_enable_sysctl(struct ctl_table *table, int write, |
5072c59f | 1359 | struct file *file, void __user *buffer, size_t *lenp, |
b0fc494f SR |
1360 | loff_t *ppos) |
1361 | { | |
1362 | int ret; | |
1363 | ||
4eebcc81 SR |
1364 | if (unlikely(ftrace_disabled)) |
1365 | return -ENODEV; | |
1366 | ||
b0fc494f SR |
1367 | mutex_lock(&ftrace_sysctl_lock); |
1368 | ||
5072c59f | 1369 | ret = proc_dointvec(table, write, file, buffer, lenp, ppos); |
b0fc494f SR |
1370 | |
1371 | if (ret || !write || (last_ftrace_enabled == ftrace_enabled)) | |
1372 | goto out; | |
1373 | ||
1374 | last_ftrace_enabled = ftrace_enabled; | |
1375 | ||
1376 | if (ftrace_enabled) { | |
1377 | ||
1378 | ftrace_startup_sysctl(); | |
1379 | ||
1380 | /* we are starting ftrace again */ | |
1381 | if (ftrace_list != &ftrace_list_end) { | |
1382 | if (ftrace_list->next == &ftrace_list_end) | |
1383 | ftrace_trace_function = ftrace_list->func; | |
1384 | else | |
1385 | ftrace_trace_function = ftrace_list_func; | |
1386 | } | |
1387 | ||
1388 | } else { | |
1389 | /* stopping ftrace calls (just send to ftrace_stub) */ | |
1390 | ftrace_trace_function = ftrace_stub; | |
1391 | ||
1392 | ftrace_shutdown_sysctl(); | |
1393 | } | |
1394 | ||
1395 | out: | |
1396 | mutex_unlock(&ftrace_sysctl_lock); | |
3d083395 | 1397 | return ret; |
16444a8a | 1398 | } |