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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
fe9d4f57 AD |
2 | #include <linux/kdebug.h> |
3 | #include <linux/kprobes.h> | |
9984de1a | 4 | #include <linux/export.h> |
fe9d4f57 AD |
5 | #include <linux/notifier.h> |
6 | #include <linux/rcupdate.h> | |
7 | #include <linux/vmalloc.h> | |
c166f23c | 8 | #include <linux/reboot.h> |
fe9d4f57 AD |
9 | |
10 | /* | |
11 | * Notifier list for kernel code which wants to be called | |
12 | * at shutdown. This is used to stop any idling DMA operations | |
13 | * and the like. | |
14 | */ | |
15 | BLOCKING_NOTIFIER_HEAD(reboot_notifier_list); | |
16 | ||
17 | /* | |
18 | * Notifier chain core routines. The exported routines below | |
19 | * are layered on top of these, with appropriate locking added. | |
20 | */ | |
21 | ||
22 | static int notifier_chain_register(struct notifier_block **nl, | |
5abb065d | 23 | struct notifier_block *n) |
fe9d4f57 AD |
24 | { |
25 | while ((*nl) != NULL) { | |
1a50cb80 | 26 | if (unlikely((*nl) == n)) { |
5abb065d BP |
27 | WARN(1, "notifier callback %ps already registered", |
28 | n->notifier_call); | |
29 | return -EEXIST; | |
1a50cb80 | 30 | } |
fe9d4f57 AD |
31 | if (n->priority > (*nl)->priority) |
32 | break; | |
33 | nl = &((*nl)->next); | |
34 | } | |
35 | n->next = *nl; | |
36 | rcu_assign_pointer(*nl, n); | |
37 | return 0; | |
38 | } | |
39 | ||
40 | static int notifier_chain_unregister(struct notifier_block **nl, | |
41 | struct notifier_block *n) | |
42 | { | |
43 | while ((*nl) != NULL) { | |
44 | if ((*nl) == n) { | |
45 | rcu_assign_pointer(*nl, n->next); | |
46 | return 0; | |
47 | } | |
48 | nl = &((*nl)->next); | |
49 | } | |
50 | return -ENOENT; | |
51 | } | |
52 | ||
53 | /** | |
54 | * notifier_call_chain - Informs the registered notifiers about an event. | |
55 | * @nl: Pointer to head of the blocking notifier chain | |
56 | * @val: Value passed unmodified to notifier function | |
57 | * @v: Pointer passed unmodified to notifier function | |
58 | * @nr_to_call: Number of notifier functions to be called. Don't care | |
59 | * value of this parameter is -1. | |
60 | * @nr_calls: Records the number of notifications sent. Don't care | |
61 | * value of this field is NULL. | |
62 | * @returns: notifier_call_chain returns the value returned by the | |
63 | * last notifier function called. | |
64 | */ | |
b40a2cb6 MH |
65 | static int notifier_call_chain(struct notifier_block **nl, |
66 | unsigned long val, void *v, | |
67 | int nr_to_call, int *nr_calls) | |
fe9d4f57 AD |
68 | { |
69 | int ret = NOTIFY_DONE; | |
70 | struct notifier_block *nb, *next_nb; | |
71 | ||
d11c563d | 72 | nb = rcu_dereference_raw(*nl); |
fe9d4f57 AD |
73 | |
74 | while (nb && nr_to_call) { | |
d11c563d | 75 | next_nb = rcu_dereference_raw(nb->next); |
1b2439db AV |
76 | |
77 | #ifdef CONFIG_DEBUG_NOTIFIERS | |
ab7476cf | 78 | if (unlikely(!func_ptr_is_kernel_text(nb->notifier_call))) { |
1b2439db AV |
79 | WARN(1, "Invalid notifier called!"); |
80 | nb = next_nb; | |
81 | continue; | |
82 | } | |
83 | #endif | |
fe9d4f57 AD |
84 | ret = nb->notifier_call(nb, val, v); |
85 | ||
86 | if (nr_calls) | |
87 | (*nr_calls)++; | |
88 | ||
3e6daded | 89 | if (ret & NOTIFY_STOP_MASK) |
fe9d4f57 AD |
90 | break; |
91 | nb = next_nb; | |
92 | nr_to_call--; | |
93 | } | |
94 | return ret; | |
95 | } | |
b40a2cb6 | 96 | NOKPROBE_SYMBOL(notifier_call_chain); |
fe9d4f57 | 97 | |
70d93298 PZ |
98 | /** |
99 | * notifier_call_chain_robust - Inform the registered notifiers about an event | |
100 | * and rollback on error. | |
101 | * @nl: Pointer to head of the blocking notifier chain | |
102 | * @val_up: Value passed unmodified to the notifier function | |
103 | * @val_down: Value passed unmodified to the notifier function when recovering | |
104 | * from an error on @val_up | |
105 | * @v Pointer passed unmodified to the notifier function | |
106 | * | |
107 | * NOTE: It is important the @nl chain doesn't change between the two | |
108 | * invocations of notifier_call_chain() such that we visit the | |
109 | * exact same notifier callbacks; this rules out any RCU usage. | |
110 | * | |
111 | * Returns: the return value of the @val_up call. | |
112 | */ | |
113 | static int notifier_call_chain_robust(struct notifier_block **nl, | |
114 | unsigned long val_up, unsigned long val_down, | |
115 | void *v) | |
116 | { | |
117 | int ret, nr = 0; | |
118 | ||
119 | ret = notifier_call_chain(nl, val_up, v, -1, &nr); | |
120 | if (ret & NOTIFY_STOP_MASK) | |
121 | notifier_call_chain(nl, val_down, v, nr-1, NULL); | |
122 | ||
123 | return ret; | |
124 | } | |
125 | ||
fe9d4f57 AD |
126 | /* |
127 | * Atomic notifier chain routines. Registration and unregistration | |
128 | * use a spinlock, and call_chain is synchronized by RCU (no locks). | |
129 | */ | |
130 | ||
131 | /** | |
132 | * atomic_notifier_chain_register - Add notifier to an atomic notifier chain | |
133 | * @nh: Pointer to head of the atomic notifier chain | |
134 | * @n: New entry in notifier chain | |
135 | * | |
136 | * Adds a notifier to an atomic notifier chain. | |
137 | * | |
5abb065d | 138 | * Returns 0 on success, %-EEXIST on error. |
fe9d4f57 AD |
139 | */ |
140 | int atomic_notifier_chain_register(struct atomic_notifier_head *nh, | |
141 | struct notifier_block *n) | |
142 | { | |
143 | unsigned long flags; | |
144 | int ret; | |
145 | ||
146 | spin_lock_irqsave(&nh->lock, flags); | |
147 | ret = notifier_chain_register(&nh->head, n); | |
148 | spin_unlock_irqrestore(&nh->lock, flags); | |
149 | return ret; | |
150 | } | |
151 | EXPORT_SYMBOL_GPL(atomic_notifier_chain_register); | |
152 | ||
153 | /** | |
154 | * atomic_notifier_chain_unregister - Remove notifier from an atomic notifier chain | |
155 | * @nh: Pointer to head of the atomic notifier chain | |
156 | * @n: Entry to remove from notifier chain | |
157 | * | |
158 | * Removes a notifier from an atomic notifier chain. | |
159 | * | |
160 | * Returns zero on success or %-ENOENT on failure. | |
161 | */ | |
162 | int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh, | |
163 | struct notifier_block *n) | |
164 | { | |
165 | unsigned long flags; | |
166 | int ret; | |
167 | ||
168 | spin_lock_irqsave(&nh->lock, flags); | |
169 | ret = notifier_chain_unregister(&nh->head, n); | |
170 | spin_unlock_irqrestore(&nh->lock, flags); | |
171 | synchronize_rcu(); | |
172 | return ret; | |
173 | } | |
174 | EXPORT_SYMBOL_GPL(atomic_notifier_chain_unregister); | |
175 | ||
176 | /** | |
70d93298 | 177 | * atomic_notifier_call_chain - Call functions in an atomic notifier chain |
fe9d4f57 AD |
178 | * @nh: Pointer to head of the atomic notifier chain |
179 | * @val: Value passed unmodified to notifier function | |
180 | * @v: Pointer passed unmodified to notifier function | |
fe9d4f57 AD |
181 | * |
182 | * Calls each function in a notifier chain in turn. The functions | |
183 | * run in an atomic context, so they must not block. | |
184 | * This routine uses RCU to synchronize with changes to the chain. | |
185 | * | |
186 | * If the return value of the notifier can be and'ed | |
187 | * with %NOTIFY_STOP_MASK then atomic_notifier_call_chain() | |
188 | * will return immediately, with the return value of | |
189 | * the notifier function which halted execution. | |
190 | * Otherwise the return value is the return value | |
191 | * of the last notifier function called. | |
192 | */ | |
70d93298 PZ |
193 | int atomic_notifier_call_chain(struct atomic_notifier_head *nh, |
194 | unsigned long val, void *v) | |
fe9d4f57 AD |
195 | { |
196 | int ret; | |
197 | ||
198 | rcu_read_lock(); | |
70d93298 | 199 | ret = notifier_call_chain(&nh->head, val, v, -1, NULL); |
fe9d4f57 | 200 | rcu_read_unlock(); |
fe9d4f57 | 201 | |
70d93298 | 202 | return ret; |
fe9d4f57 AD |
203 | } |
204 | EXPORT_SYMBOL_GPL(atomic_notifier_call_chain); | |
b40a2cb6 | 205 | NOKPROBE_SYMBOL(atomic_notifier_call_chain); |
fe9d4f57 AD |
206 | |
207 | /* | |
208 | * Blocking notifier chain routines. All access to the chain is | |
209 | * synchronized by an rwsem. | |
210 | */ | |
211 | ||
212 | /** | |
213 | * blocking_notifier_chain_register - Add notifier to a blocking notifier chain | |
214 | * @nh: Pointer to head of the blocking notifier chain | |
215 | * @n: New entry in notifier chain | |
216 | * | |
217 | * Adds a notifier to a blocking notifier chain. | |
218 | * Must be called in process context. | |
219 | * | |
5abb065d | 220 | * Returns 0 on success, %-EEXIST on error. |
fe9d4f57 AD |
221 | */ |
222 | int blocking_notifier_chain_register(struct blocking_notifier_head *nh, | |
223 | struct notifier_block *n) | |
224 | { | |
225 | int ret; | |
226 | ||
227 | /* | |
228 | * This code gets used during boot-up, when task switching is | |
229 | * not yet working and interrupts must remain disabled. At | |
230 | * such times we must not call down_write(). | |
231 | */ | |
232 | if (unlikely(system_state == SYSTEM_BOOTING)) | |
233 | return notifier_chain_register(&nh->head, n); | |
234 | ||
235 | down_write(&nh->rwsem); | |
236 | ret = notifier_chain_register(&nh->head, n); | |
237 | up_write(&nh->rwsem); | |
238 | return ret; | |
239 | } | |
240 | EXPORT_SYMBOL_GPL(blocking_notifier_chain_register); | |
241 | ||
242 | /** | |
243 | * blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain | |
244 | * @nh: Pointer to head of the blocking notifier chain | |
245 | * @n: Entry to remove from notifier chain | |
246 | * | |
247 | * Removes a notifier from a blocking notifier chain. | |
248 | * Must be called from process context. | |
249 | * | |
250 | * Returns zero on success or %-ENOENT on failure. | |
251 | */ | |
252 | int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh, | |
253 | struct notifier_block *n) | |
254 | { | |
255 | int ret; | |
256 | ||
257 | /* | |
258 | * This code gets used during boot-up, when task switching is | |
259 | * not yet working and interrupts must remain disabled. At | |
260 | * such times we must not call down_write(). | |
261 | */ | |
262 | if (unlikely(system_state == SYSTEM_BOOTING)) | |
263 | return notifier_chain_unregister(&nh->head, n); | |
264 | ||
265 | down_write(&nh->rwsem); | |
266 | ret = notifier_chain_unregister(&nh->head, n); | |
267 | up_write(&nh->rwsem); | |
268 | return ret; | |
269 | } | |
270 | EXPORT_SYMBOL_GPL(blocking_notifier_chain_unregister); | |
271 | ||
70d93298 PZ |
272 | int blocking_notifier_call_chain_robust(struct blocking_notifier_head *nh, |
273 | unsigned long val_up, unsigned long val_down, void *v) | |
274 | { | |
275 | int ret = NOTIFY_DONE; | |
276 | ||
277 | /* | |
278 | * We check the head outside the lock, but if this access is | |
279 | * racy then it does not matter what the result of the test | |
280 | * is, we re-check the list after having taken the lock anyway: | |
281 | */ | |
282 | if (rcu_access_pointer(nh->head)) { | |
283 | down_read(&nh->rwsem); | |
284 | ret = notifier_call_chain_robust(&nh->head, val_up, val_down, v); | |
285 | up_read(&nh->rwsem); | |
286 | } | |
287 | return ret; | |
288 | } | |
289 | EXPORT_SYMBOL_GPL(blocking_notifier_call_chain_robust); | |
290 | ||
fe9d4f57 | 291 | /** |
70d93298 | 292 | * blocking_notifier_call_chain - Call functions in a blocking notifier chain |
fe9d4f57 AD |
293 | * @nh: Pointer to head of the blocking notifier chain |
294 | * @val: Value passed unmodified to notifier function | |
295 | * @v: Pointer passed unmodified to notifier function | |
fe9d4f57 AD |
296 | * |
297 | * Calls each function in a notifier chain in turn. The functions | |
298 | * run in a process context, so they are allowed to block. | |
299 | * | |
300 | * If the return value of the notifier can be and'ed | |
301 | * with %NOTIFY_STOP_MASK then blocking_notifier_call_chain() | |
302 | * will return immediately, with the return value of | |
303 | * the notifier function which halted execution. | |
304 | * Otherwise the return value is the return value | |
305 | * of the last notifier function called. | |
306 | */ | |
70d93298 PZ |
307 | int blocking_notifier_call_chain(struct blocking_notifier_head *nh, |
308 | unsigned long val, void *v) | |
fe9d4f57 AD |
309 | { |
310 | int ret = NOTIFY_DONE; | |
311 | ||
312 | /* | |
313 | * We check the head outside the lock, but if this access is | |
314 | * racy then it does not matter what the result of the test | |
315 | * is, we re-check the list after having taken the lock anyway: | |
316 | */ | |
8857563b | 317 | if (rcu_access_pointer(nh->head)) { |
fe9d4f57 | 318 | down_read(&nh->rwsem); |
70d93298 | 319 | ret = notifier_call_chain(&nh->head, val, v, -1, NULL); |
fe9d4f57 AD |
320 | up_read(&nh->rwsem); |
321 | } | |
322 | return ret; | |
323 | } | |
fe9d4f57 AD |
324 | EXPORT_SYMBOL_GPL(blocking_notifier_call_chain); |
325 | ||
326 | /* | |
327 | * Raw notifier chain routines. There is no protection; | |
328 | * the caller must provide it. Use at your own risk! | |
329 | */ | |
330 | ||
331 | /** | |
332 | * raw_notifier_chain_register - Add notifier to a raw notifier chain | |
333 | * @nh: Pointer to head of the raw notifier chain | |
334 | * @n: New entry in notifier chain | |
335 | * | |
336 | * Adds a notifier to a raw notifier chain. | |
337 | * All locking must be provided by the caller. | |
338 | * | |
5abb065d | 339 | * Returns 0 on success, %-EEXIST on error. |
fe9d4f57 AD |
340 | */ |
341 | int raw_notifier_chain_register(struct raw_notifier_head *nh, | |
342 | struct notifier_block *n) | |
343 | { | |
344 | return notifier_chain_register(&nh->head, n); | |
345 | } | |
346 | EXPORT_SYMBOL_GPL(raw_notifier_chain_register); | |
347 | ||
348 | /** | |
349 | * raw_notifier_chain_unregister - Remove notifier from a raw notifier chain | |
350 | * @nh: Pointer to head of the raw notifier chain | |
351 | * @n: Entry to remove from notifier chain | |
352 | * | |
353 | * Removes a notifier from a raw notifier chain. | |
354 | * All locking must be provided by the caller. | |
355 | * | |
356 | * Returns zero on success or %-ENOENT on failure. | |
357 | */ | |
358 | int raw_notifier_chain_unregister(struct raw_notifier_head *nh, | |
359 | struct notifier_block *n) | |
360 | { | |
361 | return notifier_chain_unregister(&nh->head, n); | |
362 | } | |
363 | EXPORT_SYMBOL_GPL(raw_notifier_chain_unregister); | |
364 | ||
70d93298 PZ |
365 | int raw_notifier_call_chain_robust(struct raw_notifier_head *nh, |
366 | unsigned long val_up, unsigned long val_down, void *v) | |
367 | { | |
368 | return notifier_call_chain_robust(&nh->head, val_up, val_down, v); | |
369 | } | |
370 | EXPORT_SYMBOL_GPL(raw_notifier_call_chain_robust); | |
371 | ||
fe9d4f57 | 372 | /** |
70d93298 | 373 | * raw_notifier_call_chain - Call functions in a raw notifier chain |
fe9d4f57 AD |
374 | * @nh: Pointer to head of the raw notifier chain |
375 | * @val: Value passed unmodified to notifier function | |
376 | * @v: Pointer passed unmodified to notifier function | |
fe9d4f57 AD |
377 | * |
378 | * Calls each function in a notifier chain in turn. The functions | |
379 | * run in an undefined context. | |
380 | * All locking must be provided by the caller. | |
381 | * | |
382 | * If the return value of the notifier can be and'ed | |
383 | * with %NOTIFY_STOP_MASK then raw_notifier_call_chain() | |
384 | * will return immediately, with the return value of | |
385 | * the notifier function which halted execution. | |
386 | * Otherwise the return value is the return value | |
387 | * of the last notifier function called. | |
388 | */ | |
fe9d4f57 AD |
389 | int raw_notifier_call_chain(struct raw_notifier_head *nh, |
390 | unsigned long val, void *v) | |
391 | { | |
70d93298 | 392 | return notifier_call_chain(&nh->head, val, v, -1, NULL); |
fe9d4f57 AD |
393 | } |
394 | EXPORT_SYMBOL_GPL(raw_notifier_call_chain); | |
395 | ||
83fe27ea | 396 | #ifdef CONFIG_SRCU |
fe9d4f57 AD |
397 | /* |
398 | * SRCU notifier chain routines. Registration and unregistration | |
399 | * use a mutex, and call_chain is synchronized by SRCU (no locks). | |
400 | */ | |
401 | ||
402 | /** | |
403 | * srcu_notifier_chain_register - Add notifier to an SRCU notifier chain | |
404 | * @nh: Pointer to head of the SRCU notifier chain | |
405 | * @n: New entry in notifier chain | |
406 | * | |
407 | * Adds a notifier to an SRCU notifier chain. | |
408 | * Must be called in process context. | |
409 | * | |
5abb065d | 410 | * Returns 0 on success, %-EEXIST on error. |
fe9d4f57 AD |
411 | */ |
412 | int srcu_notifier_chain_register(struct srcu_notifier_head *nh, | |
413 | struct notifier_block *n) | |
414 | { | |
415 | int ret; | |
416 | ||
417 | /* | |
418 | * This code gets used during boot-up, when task switching is | |
419 | * not yet working and interrupts must remain disabled. At | |
420 | * such times we must not call mutex_lock(). | |
421 | */ | |
422 | if (unlikely(system_state == SYSTEM_BOOTING)) | |
423 | return notifier_chain_register(&nh->head, n); | |
424 | ||
425 | mutex_lock(&nh->mutex); | |
426 | ret = notifier_chain_register(&nh->head, n); | |
427 | mutex_unlock(&nh->mutex); | |
428 | return ret; | |
429 | } | |
430 | EXPORT_SYMBOL_GPL(srcu_notifier_chain_register); | |
431 | ||
432 | /** | |
433 | * srcu_notifier_chain_unregister - Remove notifier from an SRCU notifier chain | |
434 | * @nh: Pointer to head of the SRCU notifier chain | |
435 | * @n: Entry to remove from notifier chain | |
436 | * | |
437 | * Removes a notifier from an SRCU notifier chain. | |
438 | * Must be called from process context. | |
439 | * | |
440 | * Returns zero on success or %-ENOENT on failure. | |
441 | */ | |
442 | int srcu_notifier_chain_unregister(struct srcu_notifier_head *nh, | |
443 | struct notifier_block *n) | |
444 | { | |
445 | int ret; | |
446 | ||
447 | /* | |
448 | * This code gets used during boot-up, when task switching is | |
449 | * not yet working and interrupts must remain disabled. At | |
450 | * such times we must not call mutex_lock(). | |
451 | */ | |
452 | if (unlikely(system_state == SYSTEM_BOOTING)) | |
453 | return notifier_chain_unregister(&nh->head, n); | |
454 | ||
455 | mutex_lock(&nh->mutex); | |
456 | ret = notifier_chain_unregister(&nh->head, n); | |
457 | mutex_unlock(&nh->mutex); | |
458 | synchronize_srcu(&nh->srcu); | |
459 | return ret; | |
460 | } | |
461 | EXPORT_SYMBOL_GPL(srcu_notifier_chain_unregister); | |
462 | ||
463 | /** | |
70d93298 | 464 | * srcu_notifier_call_chain - Call functions in an SRCU notifier chain |
fe9d4f57 AD |
465 | * @nh: Pointer to head of the SRCU notifier chain |
466 | * @val: Value passed unmodified to notifier function | |
467 | * @v: Pointer passed unmodified to notifier function | |
fe9d4f57 AD |
468 | * |
469 | * Calls each function in a notifier chain in turn. The functions | |
470 | * run in a process context, so they are allowed to block. | |
471 | * | |
472 | * If the return value of the notifier can be and'ed | |
473 | * with %NOTIFY_STOP_MASK then srcu_notifier_call_chain() | |
474 | * will return immediately, with the return value of | |
475 | * the notifier function which halted execution. | |
476 | * Otherwise the return value is the return value | |
477 | * of the last notifier function called. | |
478 | */ | |
70d93298 PZ |
479 | int srcu_notifier_call_chain(struct srcu_notifier_head *nh, |
480 | unsigned long val, void *v) | |
fe9d4f57 AD |
481 | { |
482 | int ret; | |
483 | int idx; | |
484 | ||
485 | idx = srcu_read_lock(&nh->srcu); | |
70d93298 | 486 | ret = notifier_call_chain(&nh->head, val, v, -1, NULL); |
fe9d4f57 AD |
487 | srcu_read_unlock(&nh->srcu, idx); |
488 | return ret; | |
489 | } | |
fe9d4f57 AD |
490 | EXPORT_SYMBOL_GPL(srcu_notifier_call_chain); |
491 | ||
492 | /** | |
493 | * srcu_init_notifier_head - Initialize an SRCU notifier head | |
494 | * @nh: Pointer to head of the srcu notifier chain | |
495 | * | |
496 | * Unlike other sorts of notifier heads, SRCU notifier heads require | |
497 | * dynamic initialization. Be sure to call this routine before | |
498 | * calling any of the other SRCU notifier routines for this head. | |
499 | * | |
500 | * If an SRCU notifier head is deallocated, it must first be cleaned | |
501 | * up by calling srcu_cleanup_notifier_head(). Otherwise the head's | |
502 | * per-cpu data (used by the SRCU mechanism) will leak. | |
503 | */ | |
504 | void srcu_init_notifier_head(struct srcu_notifier_head *nh) | |
505 | { | |
506 | mutex_init(&nh->mutex); | |
507 | if (init_srcu_struct(&nh->srcu) < 0) | |
508 | BUG(); | |
509 | nh->head = NULL; | |
510 | } | |
511 | EXPORT_SYMBOL_GPL(srcu_init_notifier_head); | |
512 | ||
83fe27ea PK |
513 | #endif /* CONFIG_SRCU */ |
514 | ||
fe9d4f57 AD |
515 | static ATOMIC_NOTIFIER_HEAD(die_chain); |
516 | ||
b40a2cb6 | 517 | int notrace notify_die(enum die_val val, const char *str, |
fe9d4f57 AD |
518 | struct pt_regs *regs, long err, int trap, int sig) |
519 | { | |
520 | struct die_args args = { | |
521 | .regs = regs, | |
522 | .str = str, | |
523 | .err = err, | |
524 | .trapnr = trap, | |
525 | .signr = sig, | |
526 | ||
527 | }; | |
5778077d | 528 | RCU_LOCKDEP_WARN(!rcu_is_watching(), |
e727c7d7 | 529 | "notify_die called but RCU thinks we're quiescent"); |
fe9d4f57 AD |
530 | return atomic_notifier_call_chain(&die_chain, val, &args); |
531 | } | |
b40a2cb6 | 532 | NOKPROBE_SYMBOL(notify_die); |
fe9d4f57 AD |
533 | |
534 | int register_die_notifier(struct notifier_block *nb) | |
535 | { | |
fe9d4f57 AD |
536 | return atomic_notifier_chain_register(&die_chain, nb); |
537 | } | |
538 | EXPORT_SYMBOL_GPL(register_die_notifier); | |
539 | ||
540 | int unregister_die_notifier(struct notifier_block *nb) | |
541 | { | |
542 | return atomic_notifier_chain_unregister(&die_chain, nb); | |
543 | } | |
544 | EXPORT_SYMBOL_GPL(unregister_die_notifier); |