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97e1c18e MD |
1 | /* |
2 | * Copyright (C) 2008 Mathieu Desnoyers | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
17 | */ | |
18 | #include <linux/module.h> | |
19 | #include <linux/mutex.h> | |
20 | #include <linux/types.h> | |
21 | #include <linux/jhash.h> | |
22 | #include <linux/list.h> | |
23 | #include <linux/rcupdate.h> | |
24 | #include <linux/tracepoint.h> | |
25 | #include <linux/err.h> | |
26 | #include <linux/slab.h> | |
27 | ||
28 | extern struct tracepoint __start___tracepoints[]; | |
29 | extern struct tracepoint __stop___tracepoints[]; | |
30 | ||
31 | /* Set to 1 to enable tracepoint debug output */ | |
32 | static const int tracepoint_debug; | |
33 | ||
34 | /* | |
35 | * tracepoints_mutex nests inside module_mutex. Tracepoints mutex protects the | |
36 | * builtin and module tracepoints and the hash table. | |
37 | */ | |
38 | static DEFINE_MUTEX(tracepoints_mutex); | |
39 | ||
40 | /* | |
41 | * Tracepoint hash table, containing the active tracepoints. | |
42 | * Protected by tracepoints_mutex. | |
43 | */ | |
44 | #define TRACEPOINT_HASH_BITS 6 | |
45 | #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) | |
19dba33c | 46 | static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; |
97e1c18e MD |
47 | |
48 | /* | |
49 | * Note about RCU : | |
50 | * It is used to to delay the free of multiple probes array until a quiescent | |
51 | * state is reached. | |
52 | * Tracepoint entries modifications are protected by the tracepoints_mutex. | |
53 | */ | |
54 | struct tracepoint_entry { | |
55 | struct hlist_node hlist; | |
56 | void **funcs; | |
57 | int refcount; /* Number of times armed. 0 if disarmed. */ | |
97e1c18e MD |
58 | char name[0]; |
59 | }; | |
60 | ||
19dba33c | 61 | struct tp_probes { |
127cafbb LJ |
62 | union { |
63 | struct rcu_head rcu; | |
64 | struct list_head list; | |
65 | } u; | |
19dba33c LJ |
66 | void *probes[0]; |
67 | }; | |
97e1c18e | 68 | |
19dba33c | 69 | static inline void *allocate_probes(int count) |
97e1c18e | 70 | { |
19dba33c LJ |
71 | struct tp_probes *p = kmalloc(count * sizeof(void *) |
72 | + sizeof(struct tp_probes), GFP_KERNEL); | |
73 | return p == NULL ? NULL : p->probes; | |
97e1c18e MD |
74 | } |
75 | ||
19dba33c | 76 | static void rcu_free_old_probes(struct rcu_head *head) |
97e1c18e | 77 | { |
127cafbb | 78 | kfree(container_of(head, struct tp_probes, u.rcu)); |
19dba33c LJ |
79 | } |
80 | ||
81 | static inline void release_probes(void *old) | |
82 | { | |
83 | if (old) { | |
84 | struct tp_probes *tp_probes = container_of(old, | |
85 | struct tp_probes, probes[0]); | |
127cafbb | 86 | call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes); |
19dba33c | 87 | } |
97e1c18e MD |
88 | } |
89 | ||
90 | static void debug_print_probes(struct tracepoint_entry *entry) | |
91 | { | |
92 | int i; | |
93 | ||
19dba33c | 94 | if (!tracepoint_debug || !entry->funcs) |
97e1c18e MD |
95 | return; |
96 | ||
97 | for (i = 0; entry->funcs[i]; i++) | |
98 | printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i]); | |
99 | } | |
100 | ||
101 | static void * | |
102 | tracepoint_entry_add_probe(struct tracepoint_entry *entry, void *probe) | |
103 | { | |
104 | int nr_probes = 0; | |
105 | void **old, **new; | |
106 | ||
107 | WARN_ON(!probe); | |
108 | ||
109 | debug_print_probes(entry); | |
110 | old = entry->funcs; | |
111 | if (old) { | |
112 | /* (N -> N+1), (N != 0, 1) probes */ | |
113 | for (nr_probes = 0; old[nr_probes]; nr_probes++) | |
114 | if (old[nr_probes] == probe) | |
115 | return ERR_PTR(-EEXIST); | |
116 | } | |
117 | /* + 2 : one for new probe, one for NULL func */ | |
19dba33c | 118 | new = allocate_probes(nr_probes + 2); |
97e1c18e MD |
119 | if (new == NULL) |
120 | return ERR_PTR(-ENOMEM); | |
121 | if (old) | |
122 | memcpy(new, old, nr_probes * sizeof(void *)); | |
123 | new[nr_probes] = probe; | |
19dba33c | 124 | new[nr_probes + 1] = NULL; |
97e1c18e MD |
125 | entry->refcount = nr_probes + 1; |
126 | entry->funcs = new; | |
127 | debug_print_probes(entry); | |
128 | return old; | |
129 | } | |
130 | ||
131 | static void * | |
132 | tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe) | |
133 | { | |
134 | int nr_probes = 0, nr_del = 0, i; | |
135 | void **old, **new; | |
136 | ||
137 | old = entry->funcs; | |
138 | ||
f66af459 | 139 | if (!old) |
19dba33c | 140 | return ERR_PTR(-ENOENT); |
f66af459 | 141 | |
97e1c18e MD |
142 | debug_print_probes(entry); |
143 | /* (N -> M), (N > 1, M >= 0) probes */ | |
144 | for (nr_probes = 0; old[nr_probes]; nr_probes++) { | |
145 | if ((!probe || old[nr_probes] == probe)) | |
146 | nr_del++; | |
147 | } | |
148 | ||
149 | if (nr_probes - nr_del == 0) { | |
150 | /* N -> 0, (N > 1) */ | |
151 | entry->funcs = NULL; | |
152 | entry->refcount = 0; | |
153 | debug_print_probes(entry); | |
154 | return old; | |
155 | } else { | |
156 | int j = 0; | |
157 | /* N -> M, (N > 1, M > 0) */ | |
158 | /* + 1 for NULL */ | |
19dba33c | 159 | new = allocate_probes(nr_probes - nr_del + 1); |
97e1c18e MD |
160 | if (new == NULL) |
161 | return ERR_PTR(-ENOMEM); | |
162 | for (i = 0; old[i]; i++) | |
163 | if ((probe && old[i] != probe)) | |
164 | new[j++] = old[i]; | |
19dba33c | 165 | new[nr_probes - nr_del] = NULL; |
97e1c18e MD |
166 | entry->refcount = nr_probes - nr_del; |
167 | entry->funcs = new; | |
168 | } | |
169 | debug_print_probes(entry); | |
170 | return old; | |
171 | } | |
172 | ||
173 | /* | |
174 | * Get tracepoint if the tracepoint is present in the tracepoint hash table. | |
175 | * Must be called with tracepoints_mutex held. | |
176 | * Returns NULL if not present. | |
177 | */ | |
178 | static struct tracepoint_entry *get_tracepoint(const char *name) | |
179 | { | |
180 | struct hlist_head *head; | |
181 | struct hlist_node *node; | |
182 | struct tracepoint_entry *e; | |
183 | u32 hash = jhash(name, strlen(name), 0); | |
184 | ||
9795302a | 185 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
97e1c18e MD |
186 | hlist_for_each_entry(e, node, head, hlist) { |
187 | if (!strcmp(name, e->name)) | |
188 | return e; | |
189 | } | |
190 | return NULL; | |
191 | } | |
192 | ||
193 | /* | |
194 | * Add the tracepoint to the tracepoint hash table. Must be called with | |
195 | * tracepoints_mutex held. | |
196 | */ | |
197 | static struct tracepoint_entry *add_tracepoint(const char *name) | |
198 | { | |
199 | struct hlist_head *head; | |
200 | struct hlist_node *node; | |
201 | struct tracepoint_entry *e; | |
202 | size_t name_len = strlen(name) + 1; | |
203 | u32 hash = jhash(name, name_len-1, 0); | |
204 | ||
9795302a | 205 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
97e1c18e MD |
206 | hlist_for_each_entry(e, node, head, hlist) { |
207 | if (!strcmp(name, e->name)) { | |
208 | printk(KERN_NOTICE | |
209 | "tracepoint %s busy\n", name); | |
210 | return ERR_PTR(-EEXIST); /* Already there */ | |
211 | } | |
212 | } | |
213 | /* | |
214 | * Using kmalloc here to allocate a variable length element. Could | |
215 | * cause some memory fragmentation if overused. | |
216 | */ | |
217 | e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL); | |
218 | if (!e) | |
219 | return ERR_PTR(-ENOMEM); | |
220 | memcpy(&e->name[0], name, name_len); | |
221 | e->funcs = NULL; | |
222 | e->refcount = 0; | |
97e1c18e MD |
223 | hlist_add_head(&e->hlist, head); |
224 | return e; | |
225 | } | |
226 | ||
227 | /* | |
228 | * Remove the tracepoint from the tracepoint hash table. Must be called with | |
229 | * mutex_lock held. | |
230 | */ | |
19dba33c | 231 | static inline void remove_tracepoint(struct tracepoint_entry *e) |
97e1c18e | 232 | { |
97e1c18e | 233 | hlist_del(&e->hlist); |
97e1c18e | 234 | kfree(e); |
97e1c18e MD |
235 | } |
236 | ||
237 | /* | |
238 | * Sets the probe callback corresponding to one tracepoint. | |
239 | */ | |
240 | static void set_tracepoint(struct tracepoint_entry **entry, | |
241 | struct tracepoint *elem, int active) | |
242 | { | |
243 | WARN_ON(strcmp((*entry)->name, elem->name) != 0); | |
244 | ||
245 | /* | |
246 | * rcu_assign_pointer has a smp_wmb() which makes sure that the new | |
247 | * probe callbacks array is consistent before setting a pointer to it. | |
248 | * This array is referenced by __DO_TRACE from | |
249 | * include/linux/tracepoints.h. A matching smp_read_barrier_depends() | |
250 | * is used. | |
251 | */ | |
252 | rcu_assign_pointer(elem->funcs, (*entry)->funcs); | |
253 | elem->state = active; | |
254 | } | |
255 | ||
256 | /* | |
257 | * Disable a tracepoint and its probe callback. | |
258 | * Note: only waiting an RCU period after setting elem->call to the empty | |
259 | * function insures that the original callback is not used anymore. This insured | |
260 | * by preempt_disable around the call site. | |
261 | */ | |
262 | static void disable_tracepoint(struct tracepoint *elem) | |
263 | { | |
264 | elem->state = 0; | |
de0baf9a | 265 | rcu_assign_pointer(elem->funcs, NULL); |
97e1c18e MD |
266 | } |
267 | ||
268 | /** | |
269 | * tracepoint_update_probe_range - Update a probe range | |
270 | * @begin: beginning of the range | |
271 | * @end: end of the range | |
272 | * | |
273 | * Updates the probe callback corresponding to a range of tracepoints. | |
274 | */ | |
09933a10 JSR |
275 | void |
276 | tracepoint_update_probe_range(struct tracepoint *begin, struct tracepoint *end) | |
97e1c18e MD |
277 | { |
278 | struct tracepoint *iter; | |
279 | struct tracepoint_entry *mark_entry; | |
280 | ||
09933a10 JSR |
281 | if (!begin) { |
282 | WARN_ON_ONCE(1); | |
283 | return; | |
284 | } | |
285 | ||
97e1c18e MD |
286 | mutex_lock(&tracepoints_mutex); |
287 | for (iter = begin; iter < end; iter++) { | |
288 | mark_entry = get_tracepoint(iter->name); | |
289 | if (mark_entry) { | |
290 | set_tracepoint(&mark_entry, iter, | |
291 | !!mark_entry->refcount); | |
292 | } else { | |
293 | disable_tracepoint(iter); | |
294 | } | |
295 | } | |
296 | mutex_unlock(&tracepoints_mutex); | |
297 | } | |
298 | ||
299 | /* | |
300 | * Update probes, removing the faulty probes. | |
301 | */ | |
302 | static void tracepoint_update_probes(void) | |
303 | { | |
304 | /* Core kernel tracepoints */ | |
305 | tracepoint_update_probe_range(__start___tracepoints, | |
306 | __stop___tracepoints); | |
307 | /* tracepoints in modules. */ | |
308 | module_update_tracepoints(); | |
309 | } | |
310 | ||
127cafbb LJ |
311 | static void *tracepoint_add_probe(const char *name, void *probe) |
312 | { | |
313 | struct tracepoint_entry *entry; | |
314 | void *old; | |
315 | ||
316 | entry = get_tracepoint(name); | |
317 | if (!entry) { | |
318 | entry = add_tracepoint(name); | |
319 | if (IS_ERR(entry)) | |
320 | return entry; | |
321 | } | |
322 | old = tracepoint_entry_add_probe(entry, probe); | |
323 | if (IS_ERR(old) && !entry->refcount) | |
324 | remove_tracepoint(entry); | |
325 | return old; | |
326 | } | |
327 | ||
97e1c18e MD |
328 | /** |
329 | * tracepoint_probe_register - Connect a probe to a tracepoint | |
330 | * @name: tracepoint name | |
331 | * @probe: probe handler | |
332 | * | |
333 | * Returns 0 if ok, error value on error. | |
334 | * The probe address must at least be aligned on the architecture pointer size. | |
335 | */ | |
336 | int tracepoint_probe_register(const char *name, void *probe) | |
337 | { | |
97e1c18e MD |
338 | void *old; |
339 | ||
340 | mutex_lock(&tracepoints_mutex); | |
127cafbb | 341 | old = tracepoint_add_probe(name, probe); |
97e1c18e | 342 | mutex_unlock(&tracepoints_mutex); |
127cafbb LJ |
343 | if (IS_ERR(old)) |
344 | return PTR_ERR(old); | |
345 | ||
97e1c18e | 346 | tracepoint_update_probes(); /* may update entry */ |
19dba33c LJ |
347 | release_probes(old); |
348 | return 0; | |
97e1c18e MD |
349 | } |
350 | EXPORT_SYMBOL_GPL(tracepoint_probe_register); | |
351 | ||
127cafbb LJ |
352 | static void *tracepoint_remove_probe(const char *name, void *probe) |
353 | { | |
354 | struct tracepoint_entry *entry; | |
355 | void *old; | |
356 | ||
357 | entry = get_tracepoint(name); | |
358 | if (!entry) | |
359 | return ERR_PTR(-ENOENT); | |
360 | old = tracepoint_entry_remove_probe(entry, probe); | |
361 | if (IS_ERR(old)) | |
362 | return old; | |
363 | if (!entry->refcount) | |
364 | remove_tracepoint(entry); | |
365 | return old; | |
366 | } | |
367 | ||
97e1c18e MD |
368 | /** |
369 | * tracepoint_probe_unregister - Disconnect a probe from a tracepoint | |
370 | * @name: tracepoint name | |
371 | * @probe: probe function pointer | |
372 | * | |
373 | * We do not need to call a synchronize_sched to make sure the probes have | |
374 | * finished running before doing a module unload, because the module unload | |
375 | * itself uses stop_machine(), which insures that every preempt disabled section | |
376 | * have finished. | |
377 | */ | |
378 | int tracepoint_probe_unregister(const char *name, void *probe) | |
379 | { | |
97e1c18e | 380 | void *old; |
97e1c18e MD |
381 | |
382 | mutex_lock(&tracepoints_mutex); | |
127cafbb | 383 | old = tracepoint_remove_probe(name, probe); |
97e1c18e | 384 | mutex_unlock(&tracepoints_mutex); |
127cafbb LJ |
385 | if (IS_ERR(old)) |
386 | return PTR_ERR(old); | |
387 | ||
97e1c18e | 388 | tracepoint_update_probes(); /* may update entry */ |
19dba33c LJ |
389 | release_probes(old); |
390 | return 0; | |
97e1c18e MD |
391 | } |
392 | EXPORT_SYMBOL_GPL(tracepoint_probe_unregister); | |
393 | ||
127cafbb LJ |
394 | static LIST_HEAD(old_probes); |
395 | static int need_update; | |
396 | ||
397 | static void tracepoint_add_old_probes(void *old) | |
398 | { | |
399 | need_update = 1; | |
400 | if (old) { | |
401 | struct tp_probes *tp_probes = container_of(old, | |
402 | struct tp_probes, probes[0]); | |
403 | list_add(&tp_probes->u.list, &old_probes); | |
404 | } | |
405 | } | |
406 | ||
407 | /** | |
408 | * tracepoint_probe_register_noupdate - register a probe but not connect | |
409 | * @name: tracepoint name | |
410 | * @probe: probe handler | |
411 | * | |
412 | * caller must call tracepoint_probe_update_all() | |
413 | */ | |
414 | int tracepoint_probe_register_noupdate(const char *name, void *probe) | |
415 | { | |
416 | void *old; | |
417 | ||
418 | mutex_lock(&tracepoints_mutex); | |
419 | old = tracepoint_add_probe(name, probe); | |
420 | if (IS_ERR(old)) { | |
421 | mutex_unlock(&tracepoints_mutex); | |
422 | return PTR_ERR(old); | |
423 | } | |
424 | tracepoint_add_old_probes(old); | |
425 | mutex_unlock(&tracepoints_mutex); | |
426 | return 0; | |
427 | } | |
428 | EXPORT_SYMBOL_GPL(tracepoint_probe_register_noupdate); | |
429 | ||
430 | /** | |
431 | * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect | |
432 | * @name: tracepoint name | |
433 | * @probe: probe function pointer | |
434 | * | |
435 | * caller must call tracepoint_probe_update_all() | |
436 | */ | |
437 | int tracepoint_probe_unregister_noupdate(const char *name, void *probe) | |
438 | { | |
439 | void *old; | |
440 | ||
441 | mutex_lock(&tracepoints_mutex); | |
442 | old = tracepoint_remove_probe(name, probe); | |
443 | if (IS_ERR(old)) { | |
444 | mutex_unlock(&tracepoints_mutex); | |
445 | return PTR_ERR(old); | |
446 | } | |
447 | tracepoint_add_old_probes(old); | |
448 | mutex_unlock(&tracepoints_mutex); | |
449 | return 0; | |
450 | } | |
451 | EXPORT_SYMBOL_GPL(tracepoint_probe_unregister_noupdate); | |
452 | ||
453 | /** | |
454 | * tracepoint_probe_update_all - update tracepoints | |
455 | */ | |
456 | void tracepoint_probe_update_all(void) | |
457 | { | |
458 | LIST_HEAD(release_probes); | |
459 | struct tp_probes *pos, *next; | |
460 | ||
461 | mutex_lock(&tracepoints_mutex); | |
462 | if (!need_update) { | |
463 | mutex_unlock(&tracepoints_mutex); | |
464 | return; | |
465 | } | |
466 | if (!list_empty(&old_probes)) | |
467 | list_replace_init(&old_probes, &release_probes); | |
468 | need_update = 0; | |
469 | mutex_unlock(&tracepoints_mutex); | |
470 | ||
471 | tracepoint_update_probes(); | |
472 | list_for_each_entry_safe(pos, next, &release_probes, u.list) { | |
473 | list_del(&pos->u.list); | |
474 | call_rcu_sched(&pos->u.rcu, rcu_free_old_probes); | |
475 | } | |
476 | } | |
477 | EXPORT_SYMBOL_GPL(tracepoint_probe_update_all); | |
478 | ||
97e1c18e MD |
479 | /** |
480 | * tracepoint_get_iter_range - Get a next tracepoint iterator given a range. | |
481 | * @tracepoint: current tracepoints (in), next tracepoint (out) | |
482 | * @begin: beginning of the range | |
483 | * @end: end of the range | |
484 | * | |
485 | * Returns whether a next tracepoint has been found (1) or not (0). | |
486 | * Will return the first tracepoint in the range if the input tracepoint is | |
487 | * NULL. | |
488 | */ | |
489 | int tracepoint_get_iter_range(struct tracepoint **tracepoint, | |
490 | struct tracepoint *begin, struct tracepoint *end) | |
491 | { | |
492 | if (!*tracepoint && begin != end) { | |
493 | *tracepoint = begin; | |
494 | return 1; | |
495 | } | |
496 | if (*tracepoint >= begin && *tracepoint < end) | |
497 | return 1; | |
498 | return 0; | |
499 | } | |
500 | EXPORT_SYMBOL_GPL(tracepoint_get_iter_range); | |
501 | ||
502 | static void tracepoint_get_iter(struct tracepoint_iter *iter) | |
503 | { | |
504 | int found = 0; | |
505 | ||
506 | /* Core kernel tracepoints */ | |
507 | if (!iter->module) { | |
508 | found = tracepoint_get_iter_range(&iter->tracepoint, | |
509 | __start___tracepoints, __stop___tracepoints); | |
510 | if (found) | |
511 | goto end; | |
512 | } | |
513 | /* tracepoints in modules. */ | |
514 | found = module_get_iter_tracepoints(iter); | |
515 | end: | |
516 | if (!found) | |
517 | tracepoint_iter_reset(iter); | |
518 | } | |
519 | ||
520 | void tracepoint_iter_start(struct tracepoint_iter *iter) | |
521 | { | |
522 | tracepoint_get_iter(iter); | |
523 | } | |
524 | EXPORT_SYMBOL_GPL(tracepoint_iter_start); | |
525 | ||
526 | void tracepoint_iter_next(struct tracepoint_iter *iter) | |
527 | { | |
528 | iter->tracepoint++; | |
529 | /* | |
530 | * iter->tracepoint may be invalid because we blindly incremented it. | |
531 | * Make sure it is valid by marshalling on the tracepoints, getting the | |
532 | * tracepoints from following modules if necessary. | |
533 | */ | |
534 | tracepoint_get_iter(iter); | |
535 | } | |
536 | EXPORT_SYMBOL_GPL(tracepoint_iter_next); | |
537 | ||
538 | void tracepoint_iter_stop(struct tracepoint_iter *iter) | |
539 | { | |
540 | } | |
541 | EXPORT_SYMBOL_GPL(tracepoint_iter_stop); | |
542 | ||
543 | void tracepoint_iter_reset(struct tracepoint_iter *iter) | |
544 | { | |
545 | iter->module = NULL; | |
546 | iter->tracepoint = NULL; | |
547 | } | |
548 | EXPORT_SYMBOL_GPL(tracepoint_iter_reset); | |
32f85742 | 549 | |
227a8375 IM |
550 | #ifdef CONFIG_MODULES |
551 | ||
32f85742 MD |
552 | int tracepoint_module_notify(struct notifier_block *self, |
553 | unsigned long val, void *data) | |
554 | { | |
555 | struct module *mod = data; | |
556 | ||
557 | switch (val) { | |
558 | case MODULE_STATE_COMING: | |
559 | tracepoint_update_probe_range(mod->tracepoints, | |
560 | mod->tracepoints + mod->num_tracepoints); | |
561 | break; | |
562 | case MODULE_STATE_GOING: | |
563 | tracepoint_update_probe_range(mod->tracepoints, | |
564 | mod->tracepoints + mod->num_tracepoints); | |
565 | break; | |
566 | } | |
567 | return 0; | |
568 | } | |
569 | ||
570 | struct notifier_block tracepoint_module_nb = { | |
571 | .notifier_call = tracepoint_module_notify, | |
572 | .priority = 0, | |
573 | }; | |
574 | ||
575 | static int init_tracepoints(void) | |
576 | { | |
577 | return register_module_notifier(&tracepoint_module_nb); | |
578 | } | |
579 | __initcall(init_tracepoints); | |
227a8375 IM |
580 | |
581 | #endif /* CONFIG_MODULES */ |