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> | |
19 | #include <linux/kthread.h> | |
20 | #include <linux/hardirq.h> | |
16444a8a | 21 | #include <linux/ftrace.h> |
3d083395 | 22 | #include <linux/module.h> |
b0fc494f | 23 | #include <linux/sysctl.h> |
3d083395 SR |
24 | #include <linux/hash.h> |
25 | #include <linux/list.h> | |
26 | ||
27 | #include "trace.h" | |
16444a8a | 28 | |
b0fc494f SR |
29 | #ifdef CONFIG_DYNAMIC_FTRACE |
30 | # define FTRACE_ENABLED_INIT 1 | |
31 | #else | |
32 | # define FTRACE_ENABLED_INIT 0 | |
33 | #endif | |
34 | ||
35 | int ftrace_enabled = FTRACE_ENABLED_INIT; | |
36 | static int last_ftrace_enabled = FTRACE_ENABLED_INIT; | |
37 | ||
3d083395 | 38 | static DEFINE_SPINLOCK(ftrace_lock); |
b0fc494f SR |
39 | static DEFINE_MUTEX(ftrace_sysctl_lock); |
40 | ||
16444a8a ACM |
41 | static struct ftrace_ops ftrace_list_end __read_mostly = |
42 | { | |
43 | .func = ftrace_stub, | |
44 | }; | |
45 | ||
46 | static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end; | |
47 | ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; | |
48 | ||
49 | /* mcount is defined per arch in assembly */ | |
50 | EXPORT_SYMBOL(mcount); | |
51 | ||
52 | notrace void ftrace_list_func(unsigned long ip, unsigned long parent_ip) | |
53 | { | |
54 | struct ftrace_ops *op = ftrace_list; | |
55 | ||
56 | /* in case someone actually ports this to alpha! */ | |
57 | read_barrier_depends(); | |
58 | ||
59 | while (op != &ftrace_list_end) { | |
60 | /* silly alpha */ | |
61 | read_barrier_depends(); | |
62 | op->func(ip, parent_ip); | |
63 | op = op->next; | |
64 | }; | |
65 | } | |
66 | ||
67 | /** | |
3d083395 | 68 | * clear_ftrace_function - reset the ftrace function |
16444a8a | 69 | * |
3d083395 SR |
70 | * This NULLs the ftrace function and in essence stops |
71 | * tracing. There may be lag | |
16444a8a | 72 | */ |
3d083395 | 73 | void clear_ftrace_function(void) |
16444a8a | 74 | { |
3d083395 SR |
75 | ftrace_trace_function = ftrace_stub; |
76 | } | |
77 | ||
78 | static int notrace __register_ftrace_function(struct ftrace_ops *ops) | |
79 | { | |
80 | /* Should never be called by interrupts */ | |
81 | spin_lock(&ftrace_lock); | |
16444a8a | 82 | |
16444a8a ACM |
83 | ops->next = ftrace_list; |
84 | /* | |
85 | * We are entering ops into the ftrace_list but another | |
86 | * CPU might be walking that list. We need to make sure | |
87 | * the ops->next pointer is valid before another CPU sees | |
88 | * the ops pointer included into the ftrace_list. | |
89 | */ | |
90 | smp_wmb(); | |
91 | ftrace_list = ops; | |
3d083395 | 92 | |
b0fc494f SR |
93 | if (ftrace_enabled) { |
94 | /* | |
95 | * For one func, simply call it directly. | |
96 | * For more than one func, call the chain. | |
97 | */ | |
98 | if (ops->next == &ftrace_list_end) | |
99 | ftrace_trace_function = ops->func; | |
100 | else | |
101 | ftrace_trace_function = ftrace_list_func; | |
102 | } | |
3d083395 SR |
103 | |
104 | spin_unlock(&ftrace_lock); | |
16444a8a ACM |
105 | |
106 | return 0; | |
107 | } | |
108 | ||
3d083395 | 109 | static int notrace __unregister_ftrace_function(struct ftrace_ops *ops) |
16444a8a | 110 | { |
16444a8a ACM |
111 | struct ftrace_ops **p; |
112 | int ret = 0; | |
113 | ||
3d083395 | 114 | spin_lock(&ftrace_lock); |
16444a8a ACM |
115 | |
116 | /* | |
3d083395 SR |
117 | * If we are removing the last function, then simply point |
118 | * to the ftrace_stub. | |
16444a8a ACM |
119 | */ |
120 | if (ftrace_list == ops && ops->next == &ftrace_list_end) { | |
121 | ftrace_trace_function = ftrace_stub; | |
122 | ftrace_list = &ftrace_list_end; | |
123 | goto out; | |
124 | } | |
125 | ||
126 | for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next) | |
127 | if (*p == ops) | |
128 | break; | |
129 | ||
130 | if (*p != ops) { | |
131 | ret = -1; | |
132 | goto out; | |
133 | } | |
134 | ||
135 | *p = (*p)->next; | |
136 | ||
b0fc494f SR |
137 | if (ftrace_enabled) { |
138 | /* If we only have one func left, then call that directly */ | |
139 | if (ftrace_list == &ftrace_list_end || | |
140 | ftrace_list->next == &ftrace_list_end) | |
141 | ftrace_trace_function = ftrace_list->func; | |
142 | } | |
16444a8a ACM |
143 | |
144 | out: | |
3d083395 SR |
145 | spin_unlock(&ftrace_lock); |
146 | ||
147 | return ret; | |
148 | } | |
149 | ||
150 | #ifdef CONFIG_DYNAMIC_FTRACE | |
151 | ||
152 | static struct hlist_head ftrace_hash[FTRACE_HASHSIZE]; | |
153 | ||
154 | static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu); | |
155 | ||
156 | static DEFINE_SPINLOCK(ftrace_shutdown_lock); | |
157 | static DEFINE_MUTEX(ftraced_lock); | |
158 | ||
3c1720f0 SR |
159 | struct ftrace_page { |
160 | struct ftrace_page *next; | |
161 | int index; | |
162 | struct dyn_ftrace records[]; | |
163 | } __attribute__((packed)); | |
164 | ||
165 | #define ENTRIES_PER_PAGE \ | |
166 | ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace)) | |
167 | ||
168 | /* estimate from running different kernels */ | |
169 | #define NR_TO_INIT 10000 | |
170 | ||
171 | static struct ftrace_page *ftrace_pages_start; | |
172 | static struct ftrace_page *ftrace_pages; | |
173 | ||
3d083395 SR |
174 | static int ftraced_trigger; |
175 | static int ftraced_suspend; | |
176 | ||
177 | static int ftrace_record_suspend; | |
178 | ||
179 | static inline int | |
180 | notrace ftrace_ip_in_hash(unsigned long ip, unsigned long key) | |
181 | { | |
182 | struct dyn_ftrace *p; | |
183 | struct hlist_node *t; | |
184 | int found = 0; | |
185 | ||
186 | hlist_for_each_entry(p, t, &ftrace_hash[key], node) { | |
187 | if (p->ip == ip) { | |
188 | found = 1; | |
189 | break; | |
190 | } | |
191 | } | |
192 | ||
193 | return found; | |
194 | } | |
195 | ||
196 | static inline void notrace | |
197 | ftrace_add_hash(struct dyn_ftrace *node, unsigned long key) | |
198 | { | |
199 | hlist_add_head(&node->node, &ftrace_hash[key]); | |
200 | } | |
201 | ||
3c1720f0 SR |
202 | static notrace struct dyn_ftrace *ftrace_alloc_shutdown_node(unsigned long ip) |
203 | { | |
204 | /* If this was already converted, skip it */ | |
205 | if (ftrace_ip_converted(ip)) | |
206 | return NULL; | |
207 | ||
208 | if (ftrace_pages->index == ENTRIES_PER_PAGE) { | |
209 | if (!ftrace_pages->next) | |
210 | return NULL; | |
211 | ftrace_pages = ftrace_pages->next; | |
212 | } | |
213 | ||
214 | return &ftrace_pages->records[ftrace_pages->index++]; | |
215 | } | |
216 | ||
3d083395 SR |
217 | static void notrace |
218 | ftrace_record_ip(unsigned long ip, unsigned long parent_ip) | |
219 | { | |
220 | struct dyn_ftrace *node; | |
221 | unsigned long flags; | |
222 | unsigned long key; | |
223 | int resched; | |
224 | int atomic; | |
225 | ||
226 | resched = need_resched(); | |
227 | preempt_disable_notrace(); | |
228 | ||
229 | /* We simply need to protect against recursion */ | |
230 | __get_cpu_var(ftrace_shutdown_disable_cpu)++; | |
231 | if (__get_cpu_var(ftrace_shutdown_disable_cpu) != 1) | |
232 | goto out; | |
233 | ||
234 | if (unlikely(ftrace_record_suspend)) | |
235 | goto out; | |
236 | ||
237 | key = hash_long(ip, FTRACE_HASHBITS); | |
238 | ||
239 | WARN_ON_ONCE(key >= FTRACE_HASHSIZE); | |
240 | ||
241 | if (ftrace_ip_in_hash(ip, key)) | |
242 | goto out; | |
243 | ||
244 | atomic = irqs_disabled(); | |
245 | ||
246 | spin_lock_irqsave(&ftrace_shutdown_lock, flags); | |
247 | ||
248 | /* This ip may have hit the hash before the lock */ | |
249 | if (ftrace_ip_in_hash(ip, key)) | |
250 | goto out_unlock; | |
251 | ||
252 | /* | |
253 | * There's a slight race that the ftraced will update the | |
254 | * hash and reset here. The arch alloc is responsible | |
255 | * for seeing if the IP has already changed, and if | |
256 | * it has, the alloc will fail. | |
257 | */ | |
258 | node = ftrace_alloc_shutdown_node(ip); | |
259 | if (!node) | |
260 | goto out_unlock; | |
261 | ||
262 | node->ip = ip; | |
263 | ||
264 | ftrace_add_hash(node, key); | |
265 | ||
266 | ftraced_trigger = 1; | |
267 | ||
268 | out_unlock: | |
269 | spin_unlock_irqrestore(&ftrace_shutdown_lock, flags); | |
270 | out: | |
271 | __get_cpu_var(ftrace_shutdown_disable_cpu)--; | |
272 | ||
273 | /* prevent recursion with scheduler */ | |
274 | if (resched) | |
275 | preempt_enable_no_resched_notrace(); | |
276 | else | |
277 | preempt_enable_notrace(); | |
278 | } | |
279 | ||
280 | static struct ftrace_ops ftrace_shutdown_ops __read_mostly = | |
281 | { | |
282 | .func = ftrace_record_ip, | |
283 | }; | |
284 | ||
3c1720f0 SR |
285 | #define MCOUNT_ADDR ((long)(&mcount)) |
286 | ||
287 | static void notrace ftrace_replace_code(int saved) | |
288 | { | |
289 | unsigned char *new = NULL, *old = NULL; | |
290 | struct dyn_ftrace *rec; | |
291 | struct ftrace_page *pg; | |
292 | unsigned long ip; | |
293 | int failed; | |
294 | int i; | |
295 | ||
296 | if (saved) | |
297 | old = ftrace_nop_replace(); | |
298 | else | |
299 | new = ftrace_nop_replace(); | |
300 | ||
301 | for (pg = ftrace_pages_start; pg; pg = pg->next) { | |
302 | for (i = 0; i < pg->index; i++) { | |
303 | rec = &pg->records[i]; | |
304 | ||
305 | /* don't modify code that has already faulted */ | |
306 | if (rec->flags & FTRACE_FL_FAILED) | |
307 | continue; | |
308 | ||
309 | ip = rec->ip; | |
310 | ||
311 | if (saved) | |
312 | new = ftrace_call_replace(ip, MCOUNT_ADDR); | |
313 | else | |
314 | old = ftrace_call_replace(ip, MCOUNT_ADDR); | |
315 | ||
316 | failed = ftrace_modify_code(ip, old, new); | |
317 | if (failed) | |
318 | rec->flags |= FTRACE_FL_FAILED; | |
319 | } | |
320 | } | |
321 | } | |
322 | ||
323 | static notrace void ftrace_startup_code(void) | |
324 | { | |
325 | ftrace_replace_code(1); | |
326 | } | |
327 | ||
328 | static notrace void ftrace_shutdown_code(void) | |
329 | { | |
330 | ftrace_replace_code(0); | |
331 | } | |
332 | ||
333 | static notrace void ftrace_shutdown_replenish(void) | |
334 | { | |
335 | if (ftrace_pages->next) | |
336 | return; | |
337 | ||
338 | /* allocate another page */ | |
339 | ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL); | |
340 | } | |
3d083395 SR |
341 | |
342 | static int notrace __ftrace_modify_code(void *data) | |
343 | { | |
344 | void (*func)(void) = data; | |
345 | ||
346 | func(); | |
347 | return 0; | |
348 | } | |
349 | ||
3c1720f0 SR |
350 | static notrace void |
351 | ftrace_code_disable(struct dyn_ftrace *rec, unsigned long addr) | |
352 | { | |
353 | unsigned long ip; | |
354 | unsigned char *nop, *call; | |
355 | int failed; | |
356 | ||
357 | ip = rec->ip; | |
358 | ||
359 | nop = ftrace_nop_replace(); | |
360 | call = ftrace_call_replace(ip, addr); | |
361 | ||
362 | failed = ftrace_modify_code(ip, call, nop); | |
363 | if (failed) | |
364 | rec->flags |= FTRACE_FL_FAILED; | |
365 | } | |
366 | ||
3d083395 SR |
367 | static void notrace ftrace_run_startup_code(void) |
368 | { | |
369 | stop_machine_run(__ftrace_modify_code, ftrace_startup_code, NR_CPUS); | |
370 | } | |
371 | ||
372 | static void notrace ftrace_run_shutdown_code(void) | |
373 | { | |
374 | stop_machine_run(__ftrace_modify_code, ftrace_shutdown_code, NR_CPUS); | |
375 | } | |
376 | ||
377 | static void notrace ftrace_startup(void) | |
378 | { | |
379 | mutex_lock(&ftraced_lock); | |
380 | ftraced_suspend++; | |
381 | if (ftraced_suspend != 1) | |
382 | goto out; | |
383 | __unregister_ftrace_function(&ftrace_shutdown_ops); | |
384 | ||
b0fc494f SR |
385 | if (ftrace_enabled) |
386 | ftrace_run_startup_code(); | |
3d083395 SR |
387 | out: |
388 | mutex_unlock(&ftraced_lock); | |
389 | } | |
390 | ||
391 | static void notrace ftrace_shutdown(void) | |
392 | { | |
393 | mutex_lock(&ftraced_lock); | |
394 | ftraced_suspend--; | |
395 | if (ftraced_suspend) | |
396 | goto out; | |
397 | ||
b0fc494f SR |
398 | if (ftrace_enabled) |
399 | ftrace_run_shutdown_code(); | |
3d083395 SR |
400 | |
401 | __register_ftrace_function(&ftrace_shutdown_ops); | |
402 | out: | |
403 | mutex_unlock(&ftraced_lock); | |
404 | } | |
405 | ||
b0fc494f SR |
406 | static void notrace ftrace_startup_sysctl(void) |
407 | { | |
408 | mutex_lock(&ftraced_lock); | |
409 | /* ftraced_suspend is true if we want ftrace running */ | |
410 | if (ftraced_suspend) | |
411 | ftrace_run_startup_code(); | |
412 | mutex_unlock(&ftraced_lock); | |
413 | } | |
414 | ||
415 | static void notrace ftrace_shutdown_sysctl(void) | |
416 | { | |
417 | mutex_lock(&ftraced_lock); | |
418 | /* ftraced_suspend is true if ftrace is running */ | |
419 | if (ftraced_suspend) | |
420 | ftrace_run_shutdown_code(); | |
421 | mutex_unlock(&ftraced_lock); | |
422 | } | |
423 | ||
3d083395 SR |
424 | static cycle_t ftrace_update_time; |
425 | static unsigned long ftrace_update_cnt; | |
426 | unsigned long ftrace_update_tot_cnt; | |
427 | ||
428 | static int notrace __ftrace_update_code(void *ignore) | |
429 | { | |
430 | struct dyn_ftrace *p; | |
431 | struct hlist_head head; | |
432 | struct hlist_node *t; | |
433 | cycle_t start, stop; | |
434 | int i; | |
435 | ||
436 | /* Don't be calling ftrace ops now */ | |
437 | __unregister_ftrace_function(&ftrace_shutdown_ops); | |
438 | ||
439 | start = now(raw_smp_processor_id()); | |
440 | ftrace_update_cnt = 0; | |
441 | ||
442 | /* No locks needed, the machine is stopped! */ | |
443 | for (i = 0; i < FTRACE_HASHSIZE; i++) { | |
444 | if (hlist_empty(&ftrace_hash[i])) | |
445 | continue; | |
446 | ||
447 | head = ftrace_hash[i]; | |
448 | INIT_HLIST_HEAD(&ftrace_hash[i]); | |
449 | ||
450 | /* all CPUS are stopped, we are safe to modify code */ | |
451 | hlist_for_each_entry(p, t, &head, node) { | |
3c1720f0 | 452 | ftrace_code_disable(p, MCOUNT_ADDR); |
3d083395 SR |
453 | ftrace_update_cnt++; |
454 | } | |
455 | ||
456 | } | |
457 | ||
458 | stop = now(raw_smp_processor_id()); | |
459 | ftrace_update_time = stop - start; | |
460 | ftrace_update_tot_cnt += ftrace_update_cnt; | |
461 | ||
462 | __register_ftrace_function(&ftrace_shutdown_ops); | |
16444a8a ACM |
463 | |
464 | return 0; | |
465 | } | |
466 | ||
3d083395 SR |
467 | static void notrace ftrace_update_code(void) |
468 | { | |
469 | stop_machine_run(__ftrace_update_code, NULL, NR_CPUS); | |
470 | } | |
471 | ||
472 | static int notrace ftraced(void *ignore) | |
473 | { | |
474 | unsigned long usecs; | |
475 | ||
476 | set_current_state(TASK_INTERRUPTIBLE); | |
477 | ||
478 | while (!kthread_should_stop()) { | |
479 | ||
480 | /* check once a second */ | |
481 | schedule_timeout(HZ); | |
482 | ||
b0fc494f | 483 | mutex_lock(&ftrace_sysctl_lock); |
3d083395 | 484 | mutex_lock(&ftraced_lock); |
b0fc494f | 485 | if (ftrace_enabled && ftraced_trigger && !ftraced_suspend) { |
3d083395 SR |
486 | ftrace_record_suspend++; |
487 | ftrace_update_code(); | |
488 | usecs = nsecs_to_usecs(ftrace_update_time); | |
489 | if (ftrace_update_tot_cnt > 100000) { | |
490 | ftrace_update_tot_cnt = 0; | |
491 | pr_info("hm, dftrace overflow: %lu change%s" | |
492 | " (%lu total) in %lu usec%s\n", | |
493 | ftrace_update_cnt, | |
494 | ftrace_update_cnt != 1 ? "s" : "", | |
495 | ftrace_update_tot_cnt, | |
496 | usecs, usecs != 1 ? "s" : ""); | |
497 | WARN_ON_ONCE(1); | |
498 | } | |
499 | ftraced_trigger = 0; | |
500 | ftrace_record_suspend--; | |
501 | } | |
502 | mutex_unlock(&ftraced_lock); | |
b0fc494f | 503 | mutex_unlock(&ftrace_sysctl_lock); |
3d083395 SR |
504 | |
505 | ftrace_shutdown_replenish(); | |
506 | ||
507 | set_current_state(TASK_INTERRUPTIBLE); | |
508 | } | |
509 | __set_current_state(TASK_RUNNING); | |
510 | return 0; | |
511 | } | |
512 | ||
3c1720f0 SR |
513 | static int __init ftrace_dyn_table_alloc(void) |
514 | { | |
515 | struct ftrace_page *pg; | |
516 | int cnt; | |
517 | int i; | |
518 | int ret; | |
519 | ||
520 | ret = ftrace_dyn_arch_init(); | |
521 | if (ret) | |
522 | return ret; | |
523 | ||
524 | /* allocate a few pages */ | |
525 | ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL); | |
526 | if (!ftrace_pages_start) | |
527 | return -1; | |
528 | ||
529 | /* | |
530 | * Allocate a few more pages. | |
531 | * | |
532 | * TODO: have some parser search vmlinux before | |
533 | * final linking to find all calls to ftrace. | |
534 | * Then we can: | |
535 | * a) know how many pages to allocate. | |
536 | * and/or | |
537 | * b) set up the table then. | |
538 | * | |
539 | * The dynamic code is still necessary for | |
540 | * modules. | |
541 | */ | |
542 | ||
543 | pg = ftrace_pages = ftrace_pages_start; | |
544 | ||
545 | cnt = NR_TO_INIT / ENTRIES_PER_PAGE; | |
546 | ||
547 | for (i = 0; i < cnt; i++) { | |
548 | pg->next = (void *)get_zeroed_page(GFP_KERNEL); | |
549 | ||
550 | /* If we fail, we'll try later anyway */ | |
551 | if (!pg->next) | |
552 | break; | |
553 | ||
554 | pg = pg->next; | |
555 | } | |
556 | ||
557 | return 0; | |
558 | } | |
559 | ||
3d083395 SR |
560 | static int __init notrace ftrace_shutdown_init(void) |
561 | { | |
562 | struct task_struct *p; | |
563 | int ret; | |
564 | ||
3c1720f0 | 565 | ret = ftrace_dyn_table_alloc(); |
3d083395 SR |
566 | if (ret) |
567 | return ret; | |
568 | ||
569 | p = kthread_run(ftraced, NULL, "ftraced"); | |
570 | if (IS_ERR(p)) | |
571 | return -1; | |
572 | ||
573 | __register_ftrace_function(&ftrace_shutdown_ops); | |
574 | ||
575 | return 0; | |
576 | } | |
577 | ||
578 | core_initcall(ftrace_shutdown_init); | |
579 | #else | |
b0fc494f SR |
580 | # define ftrace_startup() do { } while (0) |
581 | # define ftrace_shutdown() do { } while (0) | |
582 | # define ftrace_startup_sysctl() do { } while (0) | |
583 | # define ftrace_shutdown_sysctl() do { } while (0) | |
3d083395 SR |
584 | #endif /* CONFIG_DYNAMIC_FTRACE */ |
585 | ||
16444a8a | 586 | /** |
3d083395 SR |
587 | * register_ftrace_function - register a function for profiling |
588 | * @ops - ops structure that holds the function for profiling. | |
16444a8a | 589 | * |
3d083395 SR |
590 | * Register a function to be called by all functions in the |
591 | * kernel. | |
592 | * | |
593 | * Note: @ops->func and all the functions it calls must be labeled | |
594 | * with "notrace", otherwise it will go into a | |
595 | * recursive loop. | |
16444a8a | 596 | */ |
3d083395 | 597 | int register_ftrace_function(struct ftrace_ops *ops) |
16444a8a | 598 | { |
b0fc494f SR |
599 | int ret; |
600 | ||
601 | mutex_lock(&ftrace_sysctl_lock); | |
3d083395 SR |
602 | ftrace_startup(); |
603 | ||
b0fc494f SR |
604 | ret = __register_ftrace_function(ops); |
605 | mutex_unlock(&ftrace_sysctl_lock); | |
606 | ||
607 | return ret; | |
3d083395 SR |
608 | } |
609 | ||
610 | /** | |
611 | * unregister_ftrace_function - unresgister a function for profiling. | |
612 | * @ops - ops structure that holds the function to unregister | |
613 | * | |
614 | * Unregister a function that was added to be called by ftrace profiling. | |
615 | */ | |
616 | int unregister_ftrace_function(struct ftrace_ops *ops) | |
617 | { | |
618 | int ret; | |
619 | ||
b0fc494f | 620 | mutex_lock(&ftrace_sysctl_lock); |
3d083395 SR |
621 | ret = __unregister_ftrace_function(ops); |
622 | ||
623 | if (ftrace_list == &ftrace_list_end) | |
624 | ftrace_shutdown(); | |
625 | ||
b0fc494f SR |
626 | mutex_unlock(&ftrace_sysctl_lock); |
627 | ||
628 | return ret; | |
629 | } | |
630 | ||
631 | notrace int | |
632 | ftrace_enable_sysctl(struct ctl_table *table, int write, | |
633 | struct file *filp, void __user *buffer, size_t *lenp, | |
634 | loff_t *ppos) | |
635 | { | |
636 | int ret; | |
637 | ||
638 | mutex_lock(&ftrace_sysctl_lock); | |
639 | ||
640 | ret = proc_dointvec(table, write, filp, buffer, lenp, ppos); | |
641 | ||
642 | if (ret || !write || (last_ftrace_enabled == ftrace_enabled)) | |
643 | goto out; | |
644 | ||
645 | last_ftrace_enabled = ftrace_enabled; | |
646 | ||
647 | if (ftrace_enabled) { | |
648 | ||
649 | ftrace_startup_sysctl(); | |
650 | ||
651 | /* we are starting ftrace again */ | |
652 | if (ftrace_list != &ftrace_list_end) { | |
653 | if (ftrace_list->next == &ftrace_list_end) | |
654 | ftrace_trace_function = ftrace_list->func; | |
655 | else | |
656 | ftrace_trace_function = ftrace_list_func; | |
657 | } | |
658 | ||
659 | } else { | |
660 | /* stopping ftrace calls (just send to ftrace_stub) */ | |
661 | ftrace_trace_function = ftrace_stub; | |
662 | ||
663 | ftrace_shutdown_sysctl(); | |
664 | } | |
665 | ||
666 | out: | |
667 | mutex_unlock(&ftrace_sysctl_lock); | |
3d083395 | 668 | return ret; |
16444a8a | 669 | } |