Alexey Dobriyan | fe9d4f5 | 2007-10-18 23:39:16 -0700 | [diff] [blame] | 1 | #include <linux/kdebug.h> |
| 2 | #include <linux/kprobes.h> |
| 3 | #include <linux/module.h> |
| 4 | #include <linux/notifier.h> |
| 5 | #include <linux/rcupdate.h> |
| 6 | #include <linux/vmalloc.h> |
Adrian Bunk | c166f23 | 2008-02-06 01:36:46 -0800 | [diff] [blame] | 7 | #include <linux/reboot.h> |
Alexey Dobriyan | fe9d4f5 | 2007-10-18 23:39:16 -0700 | [diff] [blame] | 8 | |
| 9 | /* |
| 10 | * Notifier list for kernel code which wants to be called |
| 11 | * at shutdown. This is used to stop any idling DMA operations |
| 12 | * and the like. |
| 13 | */ |
| 14 | BLOCKING_NOTIFIER_HEAD(reboot_notifier_list); |
| 15 | |
| 16 | /* |
| 17 | * Notifier chain core routines. The exported routines below |
| 18 | * are layered on top of these, with appropriate locking added. |
| 19 | */ |
| 20 | |
| 21 | static int notifier_chain_register(struct notifier_block **nl, |
| 22 | struct notifier_block *n) |
| 23 | { |
| 24 | while ((*nl) != NULL) { |
| 25 | if (n->priority > (*nl)->priority) |
| 26 | break; |
| 27 | nl = &((*nl)->next); |
| 28 | } |
| 29 | n->next = *nl; |
| 30 | rcu_assign_pointer(*nl, n); |
| 31 | return 0; |
| 32 | } |
| 33 | |
Nadia Derbey | 6546bc4 | 2008-04-29 01:00:45 -0700 | [diff] [blame] | 34 | static int notifier_chain_cond_register(struct notifier_block **nl, |
| 35 | struct notifier_block *n) |
| 36 | { |
| 37 | while ((*nl) != NULL) { |
| 38 | if ((*nl) == n) |
| 39 | return 0; |
| 40 | if (n->priority > (*nl)->priority) |
| 41 | break; |
| 42 | nl = &((*nl)->next); |
| 43 | } |
| 44 | n->next = *nl; |
| 45 | rcu_assign_pointer(*nl, n); |
| 46 | return 0; |
| 47 | } |
| 48 | |
Alexey Dobriyan | fe9d4f5 | 2007-10-18 23:39:16 -0700 | [diff] [blame] | 49 | static int notifier_chain_unregister(struct notifier_block **nl, |
| 50 | struct notifier_block *n) |
| 51 | { |
| 52 | while ((*nl) != NULL) { |
| 53 | if ((*nl) == n) { |
| 54 | rcu_assign_pointer(*nl, n->next); |
| 55 | return 0; |
| 56 | } |
| 57 | nl = &((*nl)->next); |
| 58 | } |
| 59 | return -ENOENT; |
| 60 | } |
| 61 | |
| 62 | /** |
| 63 | * notifier_call_chain - Informs the registered notifiers about an event. |
| 64 | * @nl: Pointer to head of the blocking notifier chain |
| 65 | * @val: Value passed unmodified to notifier function |
| 66 | * @v: Pointer passed unmodified to notifier function |
| 67 | * @nr_to_call: Number of notifier functions to be called. Don't care |
| 68 | * value of this parameter is -1. |
| 69 | * @nr_calls: Records the number of notifications sent. Don't care |
| 70 | * value of this field is NULL. |
| 71 | * @returns: notifier_call_chain returns the value returned by the |
| 72 | * last notifier function called. |
| 73 | */ |
| 74 | static int __kprobes notifier_call_chain(struct notifier_block **nl, |
| 75 | unsigned long val, void *v, |
| 76 | int nr_to_call, int *nr_calls) |
| 77 | { |
| 78 | int ret = NOTIFY_DONE; |
| 79 | struct notifier_block *nb, *next_nb; |
| 80 | |
| 81 | nb = rcu_dereference(*nl); |
| 82 | |
| 83 | while (nb && nr_to_call) { |
| 84 | next_nb = rcu_dereference(nb->next); |
| 85 | ret = nb->notifier_call(nb, val, v); |
| 86 | |
| 87 | if (nr_calls) |
| 88 | (*nr_calls)++; |
| 89 | |
| 90 | if ((ret & NOTIFY_STOP_MASK) == NOTIFY_STOP_MASK) |
| 91 | break; |
| 92 | nb = next_nb; |
| 93 | nr_to_call--; |
| 94 | } |
| 95 | return ret; |
| 96 | } |
| 97 | |
| 98 | /* |
| 99 | * Atomic notifier chain routines. Registration and unregistration |
| 100 | * use a spinlock, and call_chain is synchronized by RCU (no locks). |
| 101 | */ |
| 102 | |
| 103 | /** |
| 104 | * atomic_notifier_chain_register - Add notifier to an atomic notifier chain |
| 105 | * @nh: Pointer to head of the atomic notifier chain |
| 106 | * @n: New entry in notifier chain |
| 107 | * |
| 108 | * Adds a notifier to an atomic notifier chain. |
| 109 | * |
| 110 | * Currently always returns zero. |
| 111 | */ |
| 112 | int atomic_notifier_chain_register(struct atomic_notifier_head *nh, |
| 113 | struct notifier_block *n) |
| 114 | { |
| 115 | unsigned long flags; |
| 116 | int ret; |
| 117 | |
| 118 | spin_lock_irqsave(&nh->lock, flags); |
| 119 | ret = notifier_chain_register(&nh->head, n); |
| 120 | spin_unlock_irqrestore(&nh->lock, flags); |
| 121 | return ret; |
| 122 | } |
| 123 | EXPORT_SYMBOL_GPL(atomic_notifier_chain_register); |
| 124 | |
| 125 | /** |
| 126 | * atomic_notifier_chain_unregister - Remove notifier from an atomic notifier chain |
| 127 | * @nh: Pointer to head of the atomic notifier chain |
| 128 | * @n: Entry to remove from notifier chain |
| 129 | * |
| 130 | * Removes a notifier from an atomic notifier chain. |
| 131 | * |
| 132 | * Returns zero on success or %-ENOENT on failure. |
| 133 | */ |
| 134 | int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh, |
| 135 | struct notifier_block *n) |
| 136 | { |
| 137 | unsigned long flags; |
| 138 | int ret; |
| 139 | |
| 140 | spin_lock_irqsave(&nh->lock, flags); |
| 141 | ret = notifier_chain_unregister(&nh->head, n); |
| 142 | spin_unlock_irqrestore(&nh->lock, flags); |
| 143 | synchronize_rcu(); |
| 144 | return ret; |
| 145 | } |
| 146 | EXPORT_SYMBOL_GPL(atomic_notifier_chain_unregister); |
| 147 | |
| 148 | /** |
| 149 | * __atomic_notifier_call_chain - Call functions in an atomic notifier chain |
| 150 | * @nh: Pointer to head of the atomic notifier chain |
| 151 | * @val: Value passed unmodified to notifier function |
| 152 | * @v: Pointer passed unmodified to notifier function |
| 153 | * @nr_to_call: See the comment for notifier_call_chain. |
| 154 | * @nr_calls: See the comment for notifier_call_chain. |
| 155 | * |
| 156 | * Calls each function in a notifier chain in turn. The functions |
| 157 | * run in an atomic context, so they must not block. |
| 158 | * This routine uses RCU to synchronize with changes to the chain. |
| 159 | * |
| 160 | * If the return value of the notifier can be and'ed |
| 161 | * with %NOTIFY_STOP_MASK then atomic_notifier_call_chain() |
| 162 | * will return immediately, with the return value of |
| 163 | * the notifier function which halted execution. |
| 164 | * Otherwise the return value is the return value |
| 165 | * of the last notifier function called. |
| 166 | */ |
| 167 | int __kprobes __atomic_notifier_call_chain(struct atomic_notifier_head *nh, |
| 168 | unsigned long val, void *v, |
| 169 | int nr_to_call, int *nr_calls) |
| 170 | { |
| 171 | int ret; |
| 172 | |
| 173 | rcu_read_lock(); |
| 174 | ret = notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls); |
| 175 | rcu_read_unlock(); |
| 176 | return ret; |
| 177 | } |
| 178 | EXPORT_SYMBOL_GPL(__atomic_notifier_call_chain); |
| 179 | |
| 180 | int __kprobes atomic_notifier_call_chain(struct atomic_notifier_head *nh, |
| 181 | unsigned long val, void *v) |
| 182 | { |
| 183 | return __atomic_notifier_call_chain(nh, val, v, -1, NULL); |
| 184 | } |
| 185 | EXPORT_SYMBOL_GPL(atomic_notifier_call_chain); |
| 186 | |
| 187 | /* |
| 188 | * Blocking notifier chain routines. All access to the chain is |
| 189 | * synchronized by an rwsem. |
| 190 | */ |
| 191 | |
| 192 | /** |
| 193 | * blocking_notifier_chain_register - Add notifier to a blocking notifier chain |
| 194 | * @nh: Pointer to head of the blocking notifier chain |
| 195 | * @n: New entry in notifier chain |
| 196 | * |
| 197 | * Adds a notifier to a blocking notifier chain. |
| 198 | * Must be called in process context. |
| 199 | * |
| 200 | * Currently always returns zero. |
| 201 | */ |
| 202 | int blocking_notifier_chain_register(struct blocking_notifier_head *nh, |
| 203 | struct notifier_block *n) |
| 204 | { |
| 205 | int ret; |
| 206 | |
| 207 | /* |
| 208 | * This code gets used during boot-up, when task switching is |
| 209 | * not yet working and interrupts must remain disabled. At |
| 210 | * such times we must not call down_write(). |
| 211 | */ |
| 212 | if (unlikely(system_state == SYSTEM_BOOTING)) |
| 213 | return notifier_chain_register(&nh->head, n); |
| 214 | |
| 215 | down_write(&nh->rwsem); |
| 216 | ret = notifier_chain_register(&nh->head, n); |
| 217 | up_write(&nh->rwsem); |
| 218 | return ret; |
| 219 | } |
| 220 | EXPORT_SYMBOL_GPL(blocking_notifier_chain_register); |
| 221 | |
| 222 | /** |
Nadia Derbey | 6546bc4 | 2008-04-29 01:00:45 -0700 | [diff] [blame] | 223 | * blocking_notifier_chain_cond_register - Cond add notifier to a blocking notifier chain |
| 224 | * @nh: Pointer to head of the blocking notifier chain |
| 225 | * @n: New entry in notifier chain |
| 226 | * |
| 227 | * Adds a notifier to a blocking notifier chain, only if not already |
| 228 | * present in the chain. |
| 229 | * Must be called in process context. |
| 230 | * |
| 231 | * Currently always returns zero. |
| 232 | */ |
| 233 | int blocking_notifier_chain_cond_register(struct blocking_notifier_head *nh, |
| 234 | struct notifier_block *n) |
| 235 | { |
| 236 | int ret; |
| 237 | |
| 238 | down_write(&nh->rwsem); |
| 239 | ret = notifier_chain_cond_register(&nh->head, n); |
| 240 | up_write(&nh->rwsem); |
| 241 | return ret; |
| 242 | } |
| 243 | EXPORT_SYMBOL_GPL(blocking_notifier_chain_cond_register); |
| 244 | |
| 245 | /** |
Alexey Dobriyan | fe9d4f5 | 2007-10-18 23:39:16 -0700 | [diff] [blame] | 246 | * blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain |
| 247 | * @nh: Pointer to head of the blocking notifier chain |
| 248 | * @n: Entry to remove from notifier chain |
| 249 | * |
| 250 | * Removes a notifier from a blocking notifier chain. |
| 251 | * Must be called from process context. |
| 252 | * |
| 253 | * Returns zero on success or %-ENOENT on failure. |
| 254 | */ |
| 255 | int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh, |
| 256 | struct notifier_block *n) |
| 257 | { |
| 258 | int ret; |
| 259 | |
| 260 | /* |
| 261 | * This code gets used during boot-up, when task switching is |
| 262 | * not yet working and interrupts must remain disabled. At |
| 263 | * such times we must not call down_write(). |
| 264 | */ |
| 265 | if (unlikely(system_state == SYSTEM_BOOTING)) |
| 266 | return notifier_chain_unregister(&nh->head, n); |
| 267 | |
| 268 | down_write(&nh->rwsem); |
| 269 | ret = notifier_chain_unregister(&nh->head, n); |
| 270 | up_write(&nh->rwsem); |
| 271 | return ret; |
| 272 | } |
| 273 | EXPORT_SYMBOL_GPL(blocking_notifier_chain_unregister); |
| 274 | |
| 275 | /** |
| 276 | * __blocking_notifier_call_chain - Call functions in a blocking notifier chain |
| 277 | * @nh: Pointer to head of the blocking notifier chain |
| 278 | * @val: Value passed unmodified to notifier function |
| 279 | * @v: Pointer passed unmodified to notifier function |
| 280 | * @nr_to_call: See comment for notifier_call_chain. |
| 281 | * @nr_calls: See comment for notifier_call_chain. |
| 282 | * |
| 283 | * Calls each function in a notifier chain in turn. The functions |
| 284 | * run in a process context, so they are allowed to block. |
| 285 | * |
| 286 | * If the return value of the notifier can be and'ed |
| 287 | * with %NOTIFY_STOP_MASK then blocking_notifier_call_chain() |
| 288 | * will return immediately, with the return value of |
| 289 | * the notifier function which halted execution. |
| 290 | * Otherwise the return value is the return value |
| 291 | * of the last notifier function called. |
| 292 | */ |
| 293 | int __blocking_notifier_call_chain(struct blocking_notifier_head *nh, |
| 294 | unsigned long val, void *v, |
| 295 | int nr_to_call, int *nr_calls) |
| 296 | { |
| 297 | int ret = NOTIFY_DONE; |
| 298 | |
| 299 | /* |
| 300 | * We check the head outside the lock, but if this access is |
| 301 | * racy then it does not matter what the result of the test |
| 302 | * is, we re-check the list after having taken the lock anyway: |
| 303 | */ |
| 304 | if (rcu_dereference(nh->head)) { |
| 305 | down_read(&nh->rwsem); |
| 306 | ret = notifier_call_chain(&nh->head, val, v, nr_to_call, |
| 307 | nr_calls); |
| 308 | up_read(&nh->rwsem); |
| 309 | } |
| 310 | return ret; |
| 311 | } |
| 312 | EXPORT_SYMBOL_GPL(__blocking_notifier_call_chain); |
| 313 | |
| 314 | int blocking_notifier_call_chain(struct blocking_notifier_head *nh, |
| 315 | unsigned long val, void *v) |
| 316 | { |
| 317 | return __blocking_notifier_call_chain(nh, val, v, -1, NULL); |
| 318 | } |
| 319 | EXPORT_SYMBOL_GPL(blocking_notifier_call_chain); |
| 320 | |
| 321 | /* |
| 322 | * Raw notifier chain routines. There is no protection; |
| 323 | * the caller must provide it. Use at your own risk! |
| 324 | */ |
| 325 | |
| 326 | /** |
| 327 | * raw_notifier_chain_register - Add notifier to a raw notifier chain |
| 328 | * @nh: Pointer to head of the raw notifier chain |
| 329 | * @n: New entry in notifier chain |
| 330 | * |
| 331 | * Adds a notifier to a raw notifier chain. |
| 332 | * All locking must be provided by the caller. |
| 333 | * |
| 334 | * Currently always returns zero. |
| 335 | */ |
| 336 | int raw_notifier_chain_register(struct raw_notifier_head *nh, |
| 337 | struct notifier_block *n) |
| 338 | { |
| 339 | return notifier_chain_register(&nh->head, n); |
| 340 | } |
| 341 | EXPORT_SYMBOL_GPL(raw_notifier_chain_register); |
| 342 | |
| 343 | /** |
| 344 | * raw_notifier_chain_unregister - Remove notifier from a raw notifier chain |
| 345 | * @nh: Pointer to head of the raw notifier chain |
| 346 | * @n: Entry to remove from notifier chain |
| 347 | * |
| 348 | * Removes a notifier from a raw notifier chain. |
| 349 | * All locking must be provided by the caller. |
| 350 | * |
| 351 | * Returns zero on success or %-ENOENT on failure. |
| 352 | */ |
| 353 | int raw_notifier_chain_unregister(struct raw_notifier_head *nh, |
| 354 | struct notifier_block *n) |
| 355 | { |
| 356 | return notifier_chain_unregister(&nh->head, n); |
| 357 | } |
| 358 | EXPORT_SYMBOL_GPL(raw_notifier_chain_unregister); |
| 359 | |
| 360 | /** |
| 361 | * __raw_notifier_call_chain - Call functions in a raw notifier chain |
| 362 | * @nh: Pointer to head of the raw notifier chain |
| 363 | * @val: Value passed unmodified to notifier function |
| 364 | * @v: Pointer passed unmodified to notifier function |
| 365 | * @nr_to_call: See comment for notifier_call_chain. |
| 366 | * @nr_calls: See comment for notifier_call_chain |
| 367 | * |
| 368 | * Calls each function in a notifier chain in turn. The functions |
| 369 | * run in an undefined context. |
| 370 | * All locking must be provided by the caller. |
| 371 | * |
| 372 | * If the return value of the notifier can be and'ed |
| 373 | * with %NOTIFY_STOP_MASK then raw_notifier_call_chain() |
| 374 | * will return immediately, with the return value of |
| 375 | * the notifier function which halted execution. |
| 376 | * Otherwise the return value is the return value |
| 377 | * of the last notifier function called. |
| 378 | */ |
| 379 | int __raw_notifier_call_chain(struct raw_notifier_head *nh, |
| 380 | unsigned long val, void *v, |
| 381 | int nr_to_call, int *nr_calls) |
| 382 | { |
| 383 | return notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls); |
| 384 | } |
| 385 | EXPORT_SYMBOL_GPL(__raw_notifier_call_chain); |
| 386 | |
| 387 | int raw_notifier_call_chain(struct raw_notifier_head *nh, |
| 388 | unsigned long val, void *v) |
| 389 | { |
| 390 | return __raw_notifier_call_chain(nh, val, v, -1, NULL); |
| 391 | } |
| 392 | EXPORT_SYMBOL_GPL(raw_notifier_call_chain); |
| 393 | |
| 394 | /* |
| 395 | * SRCU notifier chain routines. Registration and unregistration |
| 396 | * use a mutex, and call_chain is synchronized by SRCU (no locks). |
| 397 | */ |
| 398 | |
| 399 | /** |
| 400 | * srcu_notifier_chain_register - Add notifier to an SRCU notifier chain |
| 401 | * @nh: Pointer to head of the SRCU notifier chain |
| 402 | * @n: New entry in notifier chain |
| 403 | * |
| 404 | * Adds a notifier to an SRCU notifier chain. |
| 405 | * Must be called in process context. |
| 406 | * |
| 407 | * Currently always returns zero. |
| 408 | */ |
| 409 | int srcu_notifier_chain_register(struct srcu_notifier_head *nh, |
| 410 | struct notifier_block *n) |
| 411 | { |
| 412 | int ret; |
| 413 | |
| 414 | /* |
| 415 | * This code gets used during boot-up, when task switching is |
| 416 | * not yet working and interrupts must remain disabled. At |
| 417 | * such times we must not call mutex_lock(). |
| 418 | */ |
| 419 | if (unlikely(system_state == SYSTEM_BOOTING)) |
| 420 | return notifier_chain_register(&nh->head, n); |
| 421 | |
| 422 | mutex_lock(&nh->mutex); |
| 423 | ret = notifier_chain_register(&nh->head, n); |
| 424 | mutex_unlock(&nh->mutex); |
| 425 | return ret; |
| 426 | } |
| 427 | EXPORT_SYMBOL_GPL(srcu_notifier_chain_register); |
| 428 | |
| 429 | /** |
| 430 | * srcu_notifier_chain_unregister - Remove notifier from an SRCU notifier chain |
| 431 | * @nh: Pointer to head of the SRCU notifier chain |
| 432 | * @n: Entry to remove from notifier chain |
| 433 | * |
| 434 | * Removes a notifier from an SRCU notifier chain. |
| 435 | * Must be called from process context. |
| 436 | * |
| 437 | * Returns zero on success or %-ENOENT on failure. |
| 438 | */ |
| 439 | int srcu_notifier_chain_unregister(struct srcu_notifier_head *nh, |
| 440 | struct notifier_block *n) |
| 441 | { |
| 442 | int ret; |
| 443 | |
| 444 | /* |
| 445 | * This code gets used during boot-up, when task switching is |
| 446 | * not yet working and interrupts must remain disabled. At |
| 447 | * such times we must not call mutex_lock(). |
| 448 | */ |
| 449 | if (unlikely(system_state == SYSTEM_BOOTING)) |
| 450 | return notifier_chain_unregister(&nh->head, n); |
| 451 | |
| 452 | mutex_lock(&nh->mutex); |
| 453 | ret = notifier_chain_unregister(&nh->head, n); |
| 454 | mutex_unlock(&nh->mutex); |
| 455 | synchronize_srcu(&nh->srcu); |
| 456 | return ret; |
| 457 | } |
| 458 | EXPORT_SYMBOL_GPL(srcu_notifier_chain_unregister); |
| 459 | |
| 460 | /** |
| 461 | * __srcu_notifier_call_chain - Call functions in an SRCU notifier chain |
| 462 | * @nh: Pointer to head of the SRCU notifier chain |
| 463 | * @val: Value passed unmodified to notifier function |
| 464 | * @v: Pointer passed unmodified to notifier function |
| 465 | * @nr_to_call: See comment for notifier_call_chain. |
| 466 | * @nr_calls: See comment for notifier_call_chain |
| 467 | * |
| 468 | * Calls each function in a notifier chain in turn. The functions |
| 469 | * run in a process context, so they are allowed to block. |
| 470 | * |
| 471 | * If the return value of the notifier can be and'ed |
| 472 | * with %NOTIFY_STOP_MASK then srcu_notifier_call_chain() |
| 473 | * will return immediately, with the return value of |
| 474 | * the notifier function which halted execution. |
| 475 | * Otherwise the return value is the return value |
| 476 | * of the last notifier function called. |
| 477 | */ |
| 478 | int __srcu_notifier_call_chain(struct srcu_notifier_head *nh, |
| 479 | unsigned long val, void *v, |
| 480 | int nr_to_call, int *nr_calls) |
| 481 | { |
| 482 | int ret; |
| 483 | int idx; |
| 484 | |
| 485 | idx = srcu_read_lock(&nh->srcu); |
| 486 | ret = notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls); |
| 487 | srcu_read_unlock(&nh->srcu, idx); |
| 488 | return ret; |
| 489 | } |
| 490 | EXPORT_SYMBOL_GPL(__srcu_notifier_call_chain); |
| 491 | |
| 492 | int srcu_notifier_call_chain(struct srcu_notifier_head *nh, |
| 493 | unsigned long val, void *v) |
| 494 | { |
| 495 | return __srcu_notifier_call_chain(nh, val, v, -1, NULL); |
| 496 | } |
| 497 | EXPORT_SYMBOL_GPL(srcu_notifier_call_chain); |
| 498 | |
| 499 | /** |
| 500 | * srcu_init_notifier_head - Initialize an SRCU notifier head |
| 501 | * @nh: Pointer to head of the srcu notifier chain |
| 502 | * |
| 503 | * Unlike other sorts of notifier heads, SRCU notifier heads require |
| 504 | * dynamic initialization. Be sure to call this routine before |
| 505 | * calling any of the other SRCU notifier routines for this head. |
| 506 | * |
| 507 | * If an SRCU notifier head is deallocated, it must first be cleaned |
| 508 | * up by calling srcu_cleanup_notifier_head(). Otherwise the head's |
| 509 | * per-cpu data (used by the SRCU mechanism) will leak. |
| 510 | */ |
| 511 | void srcu_init_notifier_head(struct srcu_notifier_head *nh) |
| 512 | { |
| 513 | mutex_init(&nh->mutex); |
| 514 | if (init_srcu_struct(&nh->srcu) < 0) |
| 515 | BUG(); |
| 516 | nh->head = NULL; |
| 517 | } |
| 518 | EXPORT_SYMBOL_GPL(srcu_init_notifier_head); |
| 519 | |
| 520 | /** |
| 521 | * register_reboot_notifier - Register function to be called at reboot time |
| 522 | * @nb: Info about notifier function to be called |
| 523 | * |
| 524 | * Registers a function with the list of functions |
| 525 | * to be called at reboot time. |
| 526 | * |
| 527 | * Currently always returns zero, as blocking_notifier_chain_register() |
| 528 | * always returns zero. |
| 529 | */ |
| 530 | int register_reboot_notifier(struct notifier_block *nb) |
| 531 | { |
| 532 | return blocking_notifier_chain_register(&reboot_notifier_list, nb); |
| 533 | } |
| 534 | EXPORT_SYMBOL(register_reboot_notifier); |
| 535 | |
| 536 | /** |
| 537 | * unregister_reboot_notifier - Unregister previously registered reboot notifier |
| 538 | * @nb: Hook to be unregistered |
| 539 | * |
| 540 | * Unregisters a previously registered reboot |
| 541 | * notifier function. |
| 542 | * |
| 543 | * Returns zero on success, or %-ENOENT on failure. |
| 544 | */ |
| 545 | int unregister_reboot_notifier(struct notifier_block *nb) |
| 546 | { |
| 547 | return blocking_notifier_chain_unregister(&reboot_notifier_list, nb); |
| 548 | } |
| 549 | EXPORT_SYMBOL(unregister_reboot_notifier); |
| 550 | |
| 551 | static ATOMIC_NOTIFIER_HEAD(die_chain); |
| 552 | |
| 553 | int notify_die(enum die_val val, const char *str, |
| 554 | struct pt_regs *regs, long err, int trap, int sig) |
| 555 | { |
| 556 | struct die_args args = { |
| 557 | .regs = regs, |
| 558 | .str = str, |
| 559 | .err = err, |
| 560 | .trapnr = trap, |
| 561 | .signr = sig, |
| 562 | |
| 563 | }; |
| 564 | return atomic_notifier_call_chain(&die_chain, val, &args); |
| 565 | } |
| 566 | |
| 567 | int register_die_notifier(struct notifier_block *nb) |
| 568 | { |
| 569 | vmalloc_sync_all(); |
| 570 | return atomic_notifier_chain_register(&die_chain, nb); |
| 571 | } |
| 572 | EXPORT_SYMBOL_GPL(register_die_notifier); |
| 573 | |
| 574 | int unregister_die_notifier(struct notifier_block *nb) |
| 575 | { |
| 576 | return atomic_notifier_chain_unregister(&die_chain, nb); |
| 577 | } |
| 578 | EXPORT_SYMBOL_GPL(unregister_die_notifier); |