| 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* |
| 3 | * linux/kernel/reboot.c |
| 4 | * |
| 5 | * Copyright (C) 2013 Linus Torvalds |
| 6 | */ |
| 7 | |
| 8 | #define pr_fmt(fmt) "reboot: " fmt |
| 9 | |
| 10 | #include <linux/atomic.h> |
| 11 | #include <linux/ctype.h> |
| 12 | #include <linux/export.h> |
| 13 | #include <linux/kexec.h> |
| 14 | #include <linux/kmod.h> |
| 15 | #include <linux/kmsg_dump.h> |
| 16 | #include <linux/reboot.h> |
| 17 | #include <linux/suspend.h> |
| 18 | #include <linux/syscalls.h> |
| 19 | #include <linux/syscore_ops.h> |
| 20 | #include <linux/uaccess.h> |
| 21 | |
| 22 | /* |
| 23 | * this indicates whether you can reboot with ctrl-alt-del: the default is yes |
| 24 | */ |
| 25 | |
| 26 | static int C_A_D = 1; |
| 27 | struct pid *cad_pid; |
| 28 | EXPORT_SYMBOL(cad_pid); |
| 29 | |
| 30 | #if defined(CONFIG_ARM) |
| 31 | #define DEFAULT_REBOOT_MODE = REBOOT_HARD |
| 32 | #else |
| 33 | #define DEFAULT_REBOOT_MODE |
| 34 | #endif |
| 35 | enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE; |
| 36 | EXPORT_SYMBOL_GPL(reboot_mode); |
| 37 | enum reboot_mode panic_reboot_mode = REBOOT_UNDEFINED; |
| 38 | |
| 39 | /* |
| 40 | * This variable is used privately to keep track of whether or not |
| 41 | * reboot_type is still set to its default value (i.e., reboot= hasn't |
| 42 | * been set on the command line). This is needed so that we can |
| 43 | * suppress DMI scanning for reboot quirks. Without it, it's |
| 44 | * impossible to override a faulty reboot quirk without recompiling. |
| 45 | */ |
| 46 | int reboot_default = 1; |
| 47 | int reboot_cpu; |
| 48 | enum reboot_type reboot_type = BOOT_ACPI; |
| 49 | int reboot_force; |
| 50 | |
| 51 | struct sys_off_handler { |
| 52 | struct notifier_block nb; |
| 53 | int (*sys_off_cb)(struct sys_off_data *data); |
| 54 | void *cb_data; |
| 55 | enum sys_off_mode mode; |
| 56 | bool blocking; |
| 57 | void *list; |
| 58 | }; |
| 59 | |
| 60 | /* |
| 61 | * Temporary stub that prevents linkage failure while we're in process |
| 62 | * of removing all uses of legacy pm_power_off() around the kernel. |
| 63 | */ |
| 64 | void __weak (*pm_power_off)(void); |
| 65 | |
| 66 | /** |
| 67 | * emergency_restart - reboot the system |
| 68 | * |
| 69 | * Without shutting down any hardware or taking any locks |
| 70 | * reboot the system. This is called when we know we are in |
| 71 | * trouble so this is our best effort to reboot. This is |
| 72 | * safe to call in interrupt context. |
| 73 | */ |
| 74 | void emergency_restart(void) |
| 75 | { |
| 76 | kmsg_dump(KMSG_DUMP_EMERG); |
| 77 | machine_emergency_restart(); |
| 78 | } |
| 79 | EXPORT_SYMBOL_GPL(emergency_restart); |
| 80 | |
| 81 | void kernel_restart_prepare(char *cmd) |
| 82 | { |
| 83 | blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); |
| 84 | system_state = SYSTEM_RESTART; |
| 85 | usermodehelper_disable(); |
| 86 | device_shutdown(); |
| 87 | } |
| 88 | |
| 89 | /** |
| 90 | * register_reboot_notifier - Register function to be called at reboot time |
| 91 | * @nb: Info about notifier function to be called |
| 92 | * |
| 93 | * Registers a function with the list of functions |
| 94 | * to be called at reboot time. |
| 95 | * |
| 96 | * Currently always returns zero, as blocking_notifier_chain_register() |
| 97 | * always returns zero. |
| 98 | */ |
| 99 | int register_reboot_notifier(struct notifier_block *nb) |
| 100 | { |
| 101 | return blocking_notifier_chain_register(&reboot_notifier_list, nb); |
| 102 | } |
| 103 | EXPORT_SYMBOL(register_reboot_notifier); |
| 104 | |
| 105 | /** |
| 106 | * unregister_reboot_notifier - Unregister previously registered reboot notifier |
| 107 | * @nb: Hook to be unregistered |
| 108 | * |
| 109 | * Unregisters a previously registered reboot |
| 110 | * notifier function. |
| 111 | * |
| 112 | * Returns zero on success, or %-ENOENT on failure. |
| 113 | */ |
| 114 | int unregister_reboot_notifier(struct notifier_block *nb) |
| 115 | { |
| 116 | return blocking_notifier_chain_unregister(&reboot_notifier_list, nb); |
| 117 | } |
| 118 | EXPORT_SYMBOL(unregister_reboot_notifier); |
| 119 | |
| 120 | static void devm_unregister_reboot_notifier(struct device *dev, void *res) |
| 121 | { |
| 122 | WARN_ON(unregister_reboot_notifier(*(struct notifier_block **)res)); |
| 123 | } |
| 124 | |
| 125 | int devm_register_reboot_notifier(struct device *dev, struct notifier_block *nb) |
| 126 | { |
| 127 | struct notifier_block **rcnb; |
| 128 | int ret; |
| 129 | |
| 130 | rcnb = devres_alloc(devm_unregister_reboot_notifier, |
| 131 | sizeof(*rcnb), GFP_KERNEL); |
| 132 | if (!rcnb) |
| 133 | return -ENOMEM; |
| 134 | |
| 135 | ret = register_reboot_notifier(nb); |
| 136 | if (!ret) { |
| 137 | *rcnb = nb; |
| 138 | devres_add(dev, rcnb); |
| 139 | } else { |
| 140 | devres_free(rcnb); |
| 141 | } |
| 142 | |
| 143 | return ret; |
| 144 | } |
| 145 | EXPORT_SYMBOL(devm_register_reboot_notifier); |
| 146 | |
| 147 | /* |
| 148 | * Notifier list for kernel code which wants to be called |
| 149 | * to restart the system. |
| 150 | */ |
| 151 | static ATOMIC_NOTIFIER_HEAD(restart_handler_list); |
| 152 | |
| 153 | /** |
| 154 | * register_restart_handler - Register function to be called to reset |
| 155 | * the system |
| 156 | * @nb: Info about handler function to be called |
| 157 | * @nb->priority: Handler priority. Handlers should follow the |
| 158 | * following guidelines for setting priorities. |
| 159 | * 0: Restart handler of last resort, |
| 160 | * with limited restart capabilities |
| 161 | * 128: Default restart handler; use if no other |
| 162 | * restart handler is expected to be available, |
| 163 | * and/or if restart functionality is |
| 164 | * sufficient to restart the entire system |
| 165 | * 255: Highest priority restart handler, will |
| 166 | * preempt all other restart handlers |
| 167 | * |
| 168 | * Registers a function with code to be called to restart the |
| 169 | * system. |
| 170 | * |
| 171 | * Registered functions will be called from machine_restart as last |
| 172 | * step of the restart sequence (if the architecture specific |
| 173 | * machine_restart function calls do_kernel_restart - see below |
| 174 | * for details). |
| 175 | * Registered functions are expected to restart the system immediately. |
| 176 | * If more than one function is registered, the restart handler priority |
| 177 | * selects which function will be called first. |
| 178 | * |
| 179 | * Restart handlers are expected to be registered from non-architecture |
| 180 | * code, typically from drivers. A typical use case would be a system |
| 181 | * where restart functionality is provided through a watchdog. Multiple |
| 182 | * restart handlers may exist; for example, one restart handler might |
| 183 | * restart the entire system, while another only restarts the CPU. |
| 184 | * In such cases, the restart handler which only restarts part of the |
| 185 | * hardware is expected to register with low priority to ensure that |
| 186 | * it only runs if no other means to restart the system is available. |
| 187 | * |
| 188 | * Currently always returns zero, as atomic_notifier_chain_register() |
| 189 | * always returns zero. |
| 190 | */ |
| 191 | int register_restart_handler(struct notifier_block *nb) |
| 192 | { |
| 193 | return atomic_notifier_chain_register(&restart_handler_list, nb); |
| 194 | } |
| 195 | EXPORT_SYMBOL(register_restart_handler); |
| 196 | |
| 197 | /** |
| 198 | * unregister_restart_handler - Unregister previously registered |
| 199 | * restart handler |
| 200 | * @nb: Hook to be unregistered |
| 201 | * |
| 202 | * Unregisters a previously registered restart handler function. |
| 203 | * |
| 204 | * Returns zero on success, or %-ENOENT on failure. |
| 205 | */ |
| 206 | int unregister_restart_handler(struct notifier_block *nb) |
| 207 | { |
| 208 | return atomic_notifier_chain_unregister(&restart_handler_list, nb); |
| 209 | } |
| 210 | EXPORT_SYMBOL(unregister_restart_handler); |
| 211 | |
| 212 | /** |
| 213 | * do_kernel_restart - Execute kernel restart handler call chain |
| 214 | * |
| 215 | * Calls functions registered with register_restart_handler. |
| 216 | * |
| 217 | * Expected to be called from machine_restart as last step of the restart |
| 218 | * sequence. |
| 219 | * |
| 220 | * Restarts the system immediately if a restart handler function has been |
| 221 | * registered. Otherwise does nothing. |
| 222 | */ |
| 223 | void do_kernel_restart(char *cmd) |
| 224 | { |
| 225 | atomic_notifier_call_chain(&restart_handler_list, reboot_mode, cmd); |
| 226 | } |
| 227 | |
| 228 | void migrate_to_reboot_cpu(void) |
| 229 | { |
| 230 | /* The boot cpu is always logical cpu 0 */ |
| 231 | int cpu = reboot_cpu; |
| 232 | |
| 233 | cpu_hotplug_disable(); |
| 234 | |
| 235 | /* Make certain the cpu I'm about to reboot on is online */ |
| 236 | if (!cpu_online(cpu)) |
| 237 | cpu = cpumask_first(cpu_online_mask); |
| 238 | |
| 239 | /* Prevent races with other tasks migrating this task */ |
| 240 | current->flags |= PF_NO_SETAFFINITY; |
| 241 | |
| 242 | /* Make certain I only run on the appropriate processor */ |
| 243 | set_cpus_allowed_ptr(current, cpumask_of(cpu)); |
| 244 | } |
| 245 | |
| 246 | /* |
| 247 | * Notifier list for kernel code which wants to be called |
| 248 | * to prepare system for restart. |
| 249 | */ |
| 250 | static BLOCKING_NOTIFIER_HEAD(restart_prep_handler_list); |
| 251 | |
| 252 | static void do_kernel_restart_prepare(void) |
| 253 | { |
| 254 | blocking_notifier_call_chain(&restart_prep_handler_list, 0, NULL); |
| 255 | } |
| 256 | |
| 257 | /** |
| 258 | * kernel_restart - reboot the system |
| 259 | * @cmd: pointer to buffer containing command to execute for restart |
| 260 | * or %NULL |
| 261 | * |
| 262 | * Shutdown everything and perform a clean reboot. |
| 263 | * This is not safe to call in interrupt context. |
| 264 | */ |
| 265 | void kernel_restart(char *cmd) |
| 266 | { |
| 267 | kernel_restart_prepare(cmd); |
| 268 | do_kernel_restart_prepare(); |
| 269 | migrate_to_reboot_cpu(); |
| 270 | syscore_shutdown(); |
| 271 | if (!cmd) |
| 272 | pr_emerg("Restarting system\n"); |
| 273 | else |
| 274 | pr_emerg("Restarting system with command '%s'\n", cmd); |
| 275 | kmsg_dump(KMSG_DUMP_SHUTDOWN); |
| 276 | machine_restart(cmd); |
| 277 | } |
| 278 | EXPORT_SYMBOL_GPL(kernel_restart); |
| 279 | |
| 280 | static void kernel_shutdown_prepare(enum system_states state) |
| 281 | { |
| 282 | blocking_notifier_call_chain(&reboot_notifier_list, |
| 283 | (state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL); |
| 284 | system_state = state; |
| 285 | usermodehelper_disable(); |
| 286 | device_shutdown(); |
| 287 | } |
| 288 | /** |
| 289 | * kernel_halt - halt the system |
| 290 | * |
| 291 | * Shutdown everything and perform a clean system halt. |
| 292 | */ |
| 293 | void kernel_halt(void) |
| 294 | { |
| 295 | kernel_shutdown_prepare(SYSTEM_HALT); |
| 296 | migrate_to_reboot_cpu(); |
| 297 | syscore_shutdown(); |
| 298 | pr_emerg("System halted\n"); |
| 299 | kmsg_dump(KMSG_DUMP_SHUTDOWN); |
| 300 | machine_halt(); |
| 301 | } |
| 302 | EXPORT_SYMBOL_GPL(kernel_halt); |
| 303 | |
| 304 | /* |
| 305 | * Notifier list for kernel code which wants to be called |
| 306 | * to prepare system for power off. |
| 307 | */ |
| 308 | static BLOCKING_NOTIFIER_HEAD(power_off_prep_handler_list); |
| 309 | |
| 310 | /* |
| 311 | * Notifier list for kernel code which wants to be called |
| 312 | * to power off system. |
| 313 | */ |
| 314 | static ATOMIC_NOTIFIER_HEAD(power_off_handler_list); |
| 315 | |
| 316 | static int sys_off_notify(struct notifier_block *nb, |
| 317 | unsigned long mode, void *cmd) |
| 318 | { |
| 319 | struct sys_off_handler *handler; |
| 320 | struct sys_off_data data = {}; |
| 321 | |
| 322 | handler = container_of(nb, struct sys_off_handler, nb); |
| 323 | data.cb_data = handler->cb_data; |
| 324 | data.mode = mode; |
| 325 | data.cmd = cmd; |
| 326 | |
| 327 | return handler->sys_off_cb(&data); |
| 328 | } |
| 329 | |
| 330 | static struct sys_off_handler platform_sys_off_handler; |
| 331 | |
| 332 | static struct sys_off_handler *alloc_sys_off_handler(int priority) |
| 333 | { |
| 334 | struct sys_off_handler *handler; |
| 335 | gfp_t flags; |
| 336 | |
| 337 | /* |
| 338 | * Platforms like m68k can't allocate sys_off handler dynamically |
| 339 | * at the early boot time because memory allocator isn't available yet. |
| 340 | */ |
| 341 | if (priority == SYS_OFF_PRIO_PLATFORM) { |
| 342 | handler = &platform_sys_off_handler; |
| 343 | if (handler->cb_data) |
| 344 | return ERR_PTR(-EBUSY); |
| 345 | } else { |
| 346 | if (system_state > SYSTEM_RUNNING) |
| 347 | flags = GFP_ATOMIC; |
| 348 | else |
| 349 | flags = GFP_KERNEL; |
| 350 | |
| 351 | handler = kzalloc(sizeof(*handler), flags); |
| 352 | if (!handler) |
| 353 | return ERR_PTR(-ENOMEM); |
| 354 | } |
| 355 | |
| 356 | return handler; |
| 357 | } |
| 358 | |
| 359 | static void free_sys_off_handler(struct sys_off_handler *handler) |
| 360 | { |
| 361 | if (handler == &platform_sys_off_handler) |
| 362 | memset(handler, 0, sizeof(*handler)); |
| 363 | else |
| 364 | kfree(handler); |
| 365 | } |
| 366 | |
| 367 | /** |
| 368 | * register_sys_off_handler - Register sys-off handler |
| 369 | * @mode: Sys-off mode |
| 370 | * @priority: Handler priority |
| 371 | * @callback: Callback function |
| 372 | * @cb_data: Callback argument |
| 373 | * |
| 374 | * Registers system power-off or restart handler that will be invoked |
| 375 | * at the step corresponding to the given sys-off mode. Handler's callback |
| 376 | * should return NOTIFY_DONE to permit execution of the next handler in |
| 377 | * the call chain or NOTIFY_STOP to break the chain (in error case for |
| 378 | * example). |
| 379 | * |
| 380 | * Multiple handlers can be registered at the default priority level. |
| 381 | * |
| 382 | * Only one handler can be registered at the non-default priority level, |
| 383 | * otherwise ERR_PTR(-EBUSY) is returned. |
| 384 | * |
| 385 | * Returns a new instance of struct sys_off_handler on success, or |
| 386 | * an ERR_PTR()-encoded error code otherwise. |
| 387 | */ |
| 388 | struct sys_off_handler * |
| 389 | register_sys_off_handler(enum sys_off_mode mode, |
| 390 | int priority, |
| 391 | int (*callback)(struct sys_off_data *data), |
| 392 | void *cb_data) |
| 393 | { |
| 394 | struct sys_off_handler *handler; |
| 395 | int err; |
| 396 | |
| 397 | handler = alloc_sys_off_handler(priority); |
| 398 | if (IS_ERR(handler)) |
| 399 | return handler; |
| 400 | |
| 401 | switch (mode) { |
| 402 | case SYS_OFF_MODE_POWER_OFF_PREPARE: |
| 403 | handler->list = &power_off_prep_handler_list; |
| 404 | handler->blocking = true; |
| 405 | break; |
| 406 | |
| 407 | case SYS_OFF_MODE_POWER_OFF: |
| 408 | handler->list = &power_off_handler_list; |
| 409 | break; |
| 410 | |
| 411 | case SYS_OFF_MODE_RESTART_PREPARE: |
| 412 | handler->list = &restart_prep_handler_list; |
| 413 | handler->blocking = true; |
| 414 | break; |
| 415 | |
| 416 | case SYS_OFF_MODE_RESTART: |
| 417 | handler->list = &restart_handler_list; |
| 418 | break; |
| 419 | |
| 420 | default: |
| 421 | free_sys_off_handler(handler); |
| 422 | return ERR_PTR(-EINVAL); |
| 423 | } |
| 424 | |
| 425 | handler->nb.notifier_call = sys_off_notify; |
| 426 | handler->nb.priority = priority; |
| 427 | handler->sys_off_cb = callback; |
| 428 | handler->cb_data = cb_data; |
| 429 | handler->mode = mode; |
| 430 | |
| 431 | if (handler->blocking) { |
| 432 | if (priority == SYS_OFF_PRIO_DEFAULT) |
| 433 | err = blocking_notifier_chain_register(handler->list, |
| 434 | &handler->nb); |
| 435 | else |
| 436 | err = blocking_notifier_chain_register_unique_prio(handler->list, |
| 437 | &handler->nb); |
| 438 | } else { |
| 439 | if (priority == SYS_OFF_PRIO_DEFAULT) |
| 440 | err = atomic_notifier_chain_register(handler->list, |
| 441 | &handler->nb); |
| 442 | else |
| 443 | err = atomic_notifier_chain_register_unique_prio(handler->list, |
| 444 | &handler->nb); |
| 445 | } |
| 446 | |
| 447 | if (err) { |
| 448 | free_sys_off_handler(handler); |
| 449 | return ERR_PTR(err); |
| 450 | } |
| 451 | |
| 452 | return handler; |
| 453 | } |
| 454 | EXPORT_SYMBOL_GPL(register_sys_off_handler); |
| 455 | |
| 456 | /** |
| 457 | * unregister_sys_off_handler - Unregister sys-off handler |
| 458 | * @handler: Sys-off handler |
| 459 | * |
| 460 | * Unregisters given sys-off handler. |
| 461 | */ |
| 462 | void unregister_sys_off_handler(struct sys_off_handler *handler) |
| 463 | { |
| 464 | int err; |
| 465 | |
| 466 | if (IS_ERR_OR_NULL(handler)) |
| 467 | return; |
| 468 | |
| 469 | if (handler->blocking) |
| 470 | err = blocking_notifier_chain_unregister(handler->list, |
| 471 | &handler->nb); |
| 472 | else |
| 473 | err = atomic_notifier_chain_unregister(handler->list, |
| 474 | &handler->nb); |
| 475 | |
| 476 | /* sanity check, shall never happen */ |
| 477 | WARN_ON(err); |
| 478 | |
| 479 | free_sys_off_handler(handler); |
| 480 | } |
| 481 | EXPORT_SYMBOL_GPL(unregister_sys_off_handler); |
| 482 | |
| 483 | static void devm_unregister_sys_off_handler(void *data) |
| 484 | { |
| 485 | struct sys_off_handler *handler = data; |
| 486 | |
| 487 | unregister_sys_off_handler(handler); |
| 488 | } |
| 489 | |
| 490 | /** |
| 491 | * devm_register_sys_off_handler - Register sys-off handler |
| 492 | * @dev: Device that registers handler |
| 493 | * @mode: Sys-off mode |
| 494 | * @priority: Handler priority |
| 495 | * @callback: Callback function |
| 496 | * @cb_data: Callback argument |
| 497 | * |
| 498 | * Registers resource-managed sys-off handler. |
| 499 | * |
| 500 | * Returns zero on success, or error code on failure. |
| 501 | */ |
| 502 | int devm_register_sys_off_handler(struct device *dev, |
| 503 | enum sys_off_mode mode, |
| 504 | int priority, |
| 505 | int (*callback)(struct sys_off_data *data), |
| 506 | void *cb_data) |
| 507 | { |
| 508 | struct sys_off_handler *handler; |
| 509 | |
| 510 | handler = register_sys_off_handler(mode, priority, callback, cb_data); |
| 511 | if (IS_ERR(handler)) |
| 512 | return PTR_ERR(handler); |
| 513 | |
| 514 | return devm_add_action_or_reset(dev, devm_unregister_sys_off_handler, |
| 515 | handler); |
| 516 | } |
| 517 | EXPORT_SYMBOL_GPL(devm_register_sys_off_handler); |
| 518 | |
| 519 | /** |
| 520 | * devm_register_power_off_handler - Register power-off handler |
| 521 | * @dev: Device that registers callback |
| 522 | * @callback: Callback function |
| 523 | * @cb_data: Callback's argument |
| 524 | * |
| 525 | * Registers resource-managed sys-off handler with a default priority |
| 526 | * and using power-off mode. |
| 527 | * |
| 528 | * Returns zero on success, or error code on failure. |
| 529 | */ |
| 530 | int devm_register_power_off_handler(struct device *dev, |
| 531 | int (*callback)(struct sys_off_data *data), |
| 532 | void *cb_data) |
| 533 | { |
| 534 | return devm_register_sys_off_handler(dev, |
| 535 | SYS_OFF_MODE_POWER_OFF, |
| 536 | SYS_OFF_PRIO_DEFAULT, |
| 537 | callback, cb_data); |
| 538 | } |
| 539 | EXPORT_SYMBOL_GPL(devm_register_power_off_handler); |
| 540 | |
| 541 | /** |
| 542 | * devm_register_restart_handler - Register restart handler |
| 543 | * @dev: Device that registers callback |
| 544 | * @callback: Callback function |
| 545 | * @cb_data: Callback's argument |
| 546 | * |
| 547 | * Registers resource-managed sys-off handler with a default priority |
| 548 | * and using restart mode. |
| 549 | * |
| 550 | * Returns zero on success, or error code on failure. |
| 551 | */ |
| 552 | int devm_register_restart_handler(struct device *dev, |
| 553 | int (*callback)(struct sys_off_data *data), |
| 554 | void *cb_data) |
| 555 | { |
| 556 | return devm_register_sys_off_handler(dev, |
| 557 | SYS_OFF_MODE_RESTART, |
| 558 | SYS_OFF_PRIO_DEFAULT, |
| 559 | callback, cb_data); |
| 560 | } |
| 561 | EXPORT_SYMBOL_GPL(devm_register_restart_handler); |
| 562 | |
| 563 | static struct sys_off_handler *platform_power_off_handler; |
| 564 | |
| 565 | static int platform_power_off_notify(struct sys_off_data *data) |
| 566 | { |
| 567 | void (*platform_power_power_off_cb)(void) = data->cb_data; |
| 568 | |
| 569 | platform_power_power_off_cb(); |
| 570 | |
| 571 | return NOTIFY_DONE; |
| 572 | } |
| 573 | |
| 574 | /** |
| 575 | * register_platform_power_off - Register platform-level power-off callback |
| 576 | * @power_off: Power-off callback |
| 577 | * |
| 578 | * Registers power-off callback that will be called as last step |
| 579 | * of the power-off sequence. This callback is expected to be invoked |
| 580 | * for the last resort. Only one platform power-off callback is allowed |
| 581 | * to be registered at a time. |
| 582 | * |
| 583 | * Returns zero on success, or error code on failure. |
| 584 | */ |
| 585 | int register_platform_power_off(void (*power_off)(void)) |
| 586 | { |
| 587 | struct sys_off_handler *handler; |
| 588 | |
| 589 | handler = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, |
| 590 | SYS_OFF_PRIO_PLATFORM, |
| 591 | platform_power_off_notify, |
| 592 | power_off); |
| 593 | if (IS_ERR(handler)) |
| 594 | return PTR_ERR(handler); |
| 595 | |
| 596 | platform_power_off_handler = handler; |
| 597 | |
| 598 | return 0; |
| 599 | } |
| 600 | EXPORT_SYMBOL_GPL(register_platform_power_off); |
| 601 | |
| 602 | /** |
| 603 | * unregister_platform_power_off - Unregister platform-level power-off callback |
| 604 | * @power_off: Power-off callback |
| 605 | * |
| 606 | * Unregisters previously registered platform power-off callback. |
| 607 | */ |
| 608 | void unregister_platform_power_off(void (*power_off)(void)) |
| 609 | { |
| 610 | if (platform_power_off_handler && |
| 611 | platform_power_off_handler->cb_data == power_off) { |
| 612 | unregister_sys_off_handler(platform_power_off_handler); |
| 613 | platform_power_off_handler = NULL; |
| 614 | } |
| 615 | } |
| 616 | EXPORT_SYMBOL_GPL(unregister_platform_power_off); |
| 617 | |
| 618 | static int legacy_pm_power_off(struct sys_off_data *data) |
| 619 | { |
| 620 | if (pm_power_off) |
| 621 | pm_power_off(); |
| 622 | |
| 623 | return NOTIFY_DONE; |
| 624 | } |
| 625 | |
| 626 | static void do_kernel_power_off_prepare(void) |
| 627 | { |
| 628 | blocking_notifier_call_chain(&power_off_prep_handler_list, 0, NULL); |
| 629 | } |
| 630 | |
| 631 | /** |
| 632 | * do_kernel_power_off - Execute kernel power-off handler call chain |
| 633 | * |
| 634 | * Expected to be called as last step of the power-off sequence. |
| 635 | * |
| 636 | * Powers off the system immediately if a power-off handler function has |
| 637 | * been registered. Otherwise does nothing. |
| 638 | */ |
| 639 | void do_kernel_power_off(void) |
| 640 | { |
| 641 | struct sys_off_handler *sys_off = NULL; |
| 642 | |
| 643 | /* |
| 644 | * Register sys-off handlers for legacy PM callback. This allows |
| 645 | * legacy PM callbacks temporary co-exist with the new sys-off API. |
| 646 | * |
| 647 | * TODO: Remove legacy handlers once all legacy PM users will be |
| 648 | * switched to the sys-off based APIs. |
| 649 | */ |
| 650 | if (pm_power_off) |
| 651 | sys_off = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, |
| 652 | SYS_OFF_PRIO_DEFAULT, |
| 653 | legacy_pm_power_off, NULL); |
| 654 | |
| 655 | atomic_notifier_call_chain(&power_off_handler_list, 0, NULL); |
| 656 | |
| 657 | unregister_sys_off_handler(sys_off); |
| 658 | } |
| 659 | |
| 660 | /** |
| 661 | * kernel_can_power_off - check whether system can be powered off |
| 662 | * |
| 663 | * Returns true if power-off handler is registered and system can be |
| 664 | * powered off, false otherwise. |
| 665 | */ |
| 666 | bool kernel_can_power_off(void) |
| 667 | { |
| 668 | return !atomic_notifier_call_chain_is_empty(&power_off_handler_list) || |
| 669 | pm_power_off; |
| 670 | } |
| 671 | EXPORT_SYMBOL_GPL(kernel_can_power_off); |
| 672 | |
| 673 | /** |
| 674 | * kernel_power_off - power_off the system |
| 675 | * |
| 676 | * Shutdown everything and perform a clean system power_off. |
| 677 | */ |
| 678 | void kernel_power_off(void) |
| 679 | { |
| 680 | kernel_shutdown_prepare(SYSTEM_POWER_OFF); |
| 681 | do_kernel_power_off_prepare(); |
| 682 | migrate_to_reboot_cpu(); |
| 683 | syscore_shutdown(); |
| 684 | pr_emerg("Power down\n"); |
| 685 | kmsg_dump(KMSG_DUMP_SHUTDOWN); |
| 686 | machine_power_off(); |
| 687 | } |
| 688 | EXPORT_SYMBOL_GPL(kernel_power_off); |
| 689 | |
| 690 | DEFINE_MUTEX(system_transition_mutex); |
| 691 | |
| 692 | /* |
| 693 | * Reboot system call: for obvious reasons only root may call it, |
| 694 | * and even root needs to set up some magic numbers in the registers |
| 695 | * so that some mistake won't make this reboot the whole machine. |
| 696 | * You can also set the meaning of the ctrl-alt-del-key here. |
| 697 | * |
| 698 | * reboot doesn't sync: do that yourself before calling this. |
| 699 | */ |
| 700 | SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, |
| 701 | void __user *, arg) |
| 702 | { |
| 703 | struct pid_namespace *pid_ns = task_active_pid_ns(current); |
| 704 | char buffer[256]; |
| 705 | int ret = 0; |
| 706 | |
| 707 | /* We only trust the superuser with rebooting the system. */ |
| 708 | if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT)) |
| 709 | return -EPERM; |
| 710 | |
| 711 | /* For safety, we require "magic" arguments. */ |
| 712 | if (magic1 != LINUX_REBOOT_MAGIC1 || |
| 713 | (magic2 != LINUX_REBOOT_MAGIC2 && |
| 714 | magic2 != LINUX_REBOOT_MAGIC2A && |
| 715 | magic2 != LINUX_REBOOT_MAGIC2B && |
| 716 | magic2 != LINUX_REBOOT_MAGIC2C)) |
| 717 | return -EINVAL; |
| 718 | |
| 719 | /* |
| 720 | * If pid namespaces are enabled and the current task is in a child |
| 721 | * pid_namespace, the command is handled by reboot_pid_ns() which will |
| 722 | * call do_exit(). |
| 723 | */ |
| 724 | ret = reboot_pid_ns(pid_ns, cmd); |
| 725 | if (ret) |
| 726 | return ret; |
| 727 | |
| 728 | /* Instead of trying to make the power_off code look like |
| 729 | * halt when pm_power_off is not set do it the easy way. |
| 730 | */ |
| 731 | if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !kernel_can_power_off()) |
| 732 | cmd = LINUX_REBOOT_CMD_HALT; |
| 733 | |
| 734 | mutex_lock(&system_transition_mutex); |
| 735 | switch (cmd) { |
| 736 | case LINUX_REBOOT_CMD_RESTART: |
| 737 | kernel_restart(NULL); |
| 738 | break; |
| 739 | |
| 740 | case LINUX_REBOOT_CMD_CAD_ON: |
| 741 | C_A_D = 1; |
| 742 | break; |
| 743 | |
| 744 | case LINUX_REBOOT_CMD_CAD_OFF: |
| 745 | C_A_D = 0; |
| 746 | break; |
| 747 | |
| 748 | case LINUX_REBOOT_CMD_HALT: |
| 749 | kernel_halt(); |
| 750 | do_exit(0); |
| 751 | |
| 752 | case LINUX_REBOOT_CMD_POWER_OFF: |
| 753 | kernel_power_off(); |
| 754 | do_exit(0); |
| 755 | break; |
| 756 | |
| 757 | case LINUX_REBOOT_CMD_RESTART2: |
| 758 | ret = strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1); |
| 759 | if (ret < 0) { |
| 760 | ret = -EFAULT; |
| 761 | break; |
| 762 | } |
| 763 | buffer[sizeof(buffer) - 1] = '\0'; |
| 764 | |
| 765 | kernel_restart(buffer); |
| 766 | break; |
| 767 | |
| 768 | #ifdef CONFIG_KEXEC_CORE |
| 769 | case LINUX_REBOOT_CMD_KEXEC: |
| 770 | ret = kernel_kexec(); |
| 771 | break; |
| 772 | #endif |
| 773 | |
| 774 | #ifdef CONFIG_HIBERNATION |
| 775 | case LINUX_REBOOT_CMD_SW_SUSPEND: |
| 776 | ret = hibernate(); |
| 777 | break; |
| 778 | #endif |
| 779 | |
| 780 | default: |
| 781 | ret = -EINVAL; |
| 782 | break; |
| 783 | } |
| 784 | mutex_unlock(&system_transition_mutex); |
| 785 | return ret; |
| 786 | } |
| 787 | |
| 788 | static void deferred_cad(struct work_struct *dummy) |
| 789 | { |
| 790 | kernel_restart(NULL); |
| 791 | } |
| 792 | |
| 793 | /* |
| 794 | * This function gets called by ctrl-alt-del - ie the keyboard interrupt. |
| 795 | * As it's called within an interrupt, it may NOT sync: the only choice |
| 796 | * is whether to reboot at once, or just ignore the ctrl-alt-del. |
| 797 | */ |
| 798 | void ctrl_alt_del(void) |
| 799 | { |
| 800 | static DECLARE_WORK(cad_work, deferred_cad); |
| 801 | |
| 802 | if (C_A_D) |
| 803 | schedule_work(&cad_work); |
| 804 | else |
| 805 | kill_cad_pid(SIGINT, 1); |
| 806 | } |
| 807 | |
| 808 | #define POWEROFF_CMD_PATH_LEN 256 |
| 809 | static char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff"; |
| 810 | static const char reboot_cmd[] = "/sbin/reboot"; |
| 811 | |
| 812 | static int run_cmd(const char *cmd) |
| 813 | { |
| 814 | char **argv; |
| 815 | static char *envp[] = { |
| 816 | "HOME=/", |
| 817 | "PATH=/sbin:/bin:/usr/sbin:/usr/bin", |
| 818 | NULL |
| 819 | }; |
| 820 | int ret; |
| 821 | argv = argv_split(GFP_KERNEL, cmd, NULL); |
| 822 | if (argv) { |
| 823 | ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC); |
| 824 | argv_free(argv); |
| 825 | } else { |
| 826 | ret = -ENOMEM; |
| 827 | } |
| 828 | |
| 829 | return ret; |
| 830 | } |
| 831 | |
| 832 | static int __orderly_reboot(void) |
| 833 | { |
| 834 | int ret; |
| 835 | |
| 836 | ret = run_cmd(reboot_cmd); |
| 837 | |
| 838 | if (ret) { |
| 839 | pr_warn("Failed to start orderly reboot: forcing the issue\n"); |
| 840 | emergency_sync(); |
| 841 | kernel_restart(NULL); |
| 842 | } |
| 843 | |
| 844 | return ret; |
| 845 | } |
| 846 | |
| 847 | static int __orderly_poweroff(bool force) |
| 848 | { |
| 849 | int ret; |
| 850 | |
| 851 | ret = run_cmd(poweroff_cmd); |
| 852 | |
| 853 | if (ret && force) { |
| 854 | pr_warn("Failed to start orderly shutdown: forcing the issue\n"); |
| 855 | |
| 856 | /* |
| 857 | * I guess this should try to kick off some daemon to sync and |
| 858 | * poweroff asap. Or not even bother syncing if we're doing an |
| 859 | * emergency shutdown? |
| 860 | */ |
| 861 | emergency_sync(); |
| 862 | kernel_power_off(); |
| 863 | } |
| 864 | |
| 865 | return ret; |
| 866 | } |
| 867 | |
| 868 | static bool poweroff_force; |
| 869 | |
| 870 | static void poweroff_work_func(struct work_struct *work) |
| 871 | { |
| 872 | __orderly_poweroff(poweroff_force); |
| 873 | } |
| 874 | |
| 875 | static DECLARE_WORK(poweroff_work, poweroff_work_func); |
| 876 | |
| 877 | /** |
| 878 | * orderly_poweroff - Trigger an orderly system poweroff |
| 879 | * @force: force poweroff if command execution fails |
| 880 | * |
| 881 | * This may be called from any context to trigger a system shutdown. |
| 882 | * If the orderly shutdown fails, it will force an immediate shutdown. |
| 883 | */ |
| 884 | void orderly_poweroff(bool force) |
| 885 | { |
| 886 | if (force) /* do not override the pending "true" */ |
| 887 | poweroff_force = true; |
| 888 | schedule_work(&poweroff_work); |
| 889 | } |
| 890 | EXPORT_SYMBOL_GPL(orderly_poweroff); |
| 891 | |
| 892 | static void reboot_work_func(struct work_struct *work) |
| 893 | { |
| 894 | __orderly_reboot(); |
| 895 | } |
| 896 | |
| 897 | static DECLARE_WORK(reboot_work, reboot_work_func); |
| 898 | |
| 899 | /** |
| 900 | * orderly_reboot - Trigger an orderly system reboot |
| 901 | * |
| 902 | * This may be called from any context to trigger a system reboot. |
| 903 | * If the orderly reboot fails, it will force an immediate reboot. |
| 904 | */ |
| 905 | void orderly_reboot(void) |
| 906 | { |
| 907 | schedule_work(&reboot_work); |
| 908 | } |
| 909 | EXPORT_SYMBOL_GPL(orderly_reboot); |
| 910 | |
| 911 | /** |
| 912 | * hw_failure_emergency_poweroff_func - emergency poweroff work after a known delay |
| 913 | * @work: work_struct associated with the emergency poweroff function |
| 914 | * |
| 915 | * This function is called in very critical situations to force |
| 916 | * a kernel poweroff after a configurable timeout value. |
| 917 | */ |
| 918 | static void hw_failure_emergency_poweroff_func(struct work_struct *work) |
| 919 | { |
| 920 | /* |
| 921 | * We have reached here after the emergency shutdown waiting period has |
| 922 | * expired. This means orderly_poweroff has not been able to shut off |
| 923 | * the system for some reason. |
| 924 | * |
| 925 | * Try to shut down the system immediately using kernel_power_off |
| 926 | * if populated |
| 927 | */ |
| 928 | pr_emerg("Hardware protection timed-out. Trying forced poweroff\n"); |
| 929 | kernel_power_off(); |
| 930 | |
| 931 | /* |
| 932 | * Worst of the worst case trigger emergency restart |
| 933 | */ |
| 934 | pr_emerg("Hardware protection shutdown failed. Trying emergency restart\n"); |
| 935 | emergency_restart(); |
| 936 | } |
| 937 | |
| 938 | static DECLARE_DELAYED_WORK(hw_failure_emergency_poweroff_work, |
| 939 | hw_failure_emergency_poweroff_func); |
| 940 | |
| 941 | /** |
| 942 | * hw_failure_emergency_poweroff - Trigger an emergency system poweroff |
| 943 | * |
| 944 | * This may be called from any critical situation to trigger a system shutdown |
| 945 | * after a given period of time. If time is negative this is not scheduled. |
| 946 | */ |
| 947 | static void hw_failure_emergency_poweroff(int poweroff_delay_ms) |
| 948 | { |
| 949 | if (poweroff_delay_ms <= 0) |
| 950 | return; |
| 951 | schedule_delayed_work(&hw_failure_emergency_poweroff_work, |
| 952 | msecs_to_jiffies(poweroff_delay_ms)); |
| 953 | } |
| 954 | |
| 955 | /** |
| 956 | * hw_protection_shutdown - Trigger an emergency system poweroff |
| 957 | * |
| 958 | * @reason: Reason of emergency shutdown to be printed. |
| 959 | * @ms_until_forced: Time to wait for orderly shutdown before tiggering a |
| 960 | * forced shudown. Negative value disables the forced |
| 961 | * shutdown. |
| 962 | * |
| 963 | * Initiate an emergency system shutdown in order to protect hardware from |
| 964 | * further damage. Usage examples include a thermal protection or a voltage or |
| 965 | * current regulator failures. |
| 966 | * NOTE: The request is ignored if protection shutdown is already pending even |
| 967 | * if the previous request has given a large timeout for forced shutdown. |
| 968 | * Can be called from any context. |
| 969 | */ |
| 970 | void hw_protection_shutdown(const char *reason, int ms_until_forced) |
| 971 | { |
| 972 | static atomic_t allow_proceed = ATOMIC_INIT(1); |
| 973 | |
| 974 | pr_emerg("HARDWARE PROTECTION shutdown (%s)\n", reason); |
| 975 | |
| 976 | /* Shutdown should be initiated only once. */ |
| 977 | if (!atomic_dec_and_test(&allow_proceed)) |
| 978 | return; |
| 979 | |
| 980 | /* |
| 981 | * Queue a backup emergency shutdown in the event of |
| 982 | * orderly_poweroff failure |
| 983 | */ |
| 984 | hw_failure_emergency_poweroff(ms_until_forced); |
| 985 | orderly_poweroff(true); |
| 986 | } |
| 987 | EXPORT_SYMBOL_GPL(hw_protection_shutdown); |
| 988 | |
| 989 | static int __init reboot_setup(char *str) |
| 990 | { |
| 991 | for (;;) { |
| 992 | enum reboot_mode *mode; |
| 993 | |
| 994 | /* |
| 995 | * Having anything passed on the command line via |
| 996 | * reboot= will cause us to disable DMI checking |
| 997 | * below. |
| 998 | */ |
| 999 | reboot_default = 0; |
| 1000 | |
| 1001 | if (!strncmp(str, "panic_", 6)) { |
| 1002 | mode = &panic_reboot_mode; |
| 1003 | str += 6; |
| 1004 | } else { |
| 1005 | mode = &reboot_mode; |
| 1006 | } |
| 1007 | |
| 1008 | switch (*str) { |
| 1009 | case 'w': |
| 1010 | *mode = REBOOT_WARM; |
| 1011 | break; |
| 1012 | |
| 1013 | case 'c': |
| 1014 | *mode = REBOOT_COLD; |
| 1015 | break; |
| 1016 | |
| 1017 | case 'h': |
| 1018 | *mode = REBOOT_HARD; |
| 1019 | break; |
| 1020 | |
| 1021 | case 's': |
| 1022 | /* |
| 1023 | * reboot_cpu is s[mp]#### with #### being the processor |
| 1024 | * to be used for rebooting. Skip 's' or 'smp' prefix. |
| 1025 | */ |
| 1026 | str += str[1] == 'm' && str[2] == 'p' ? 3 : 1; |
| 1027 | |
| 1028 | if (isdigit(str[0])) { |
| 1029 | int cpu = simple_strtoul(str, NULL, 0); |
| 1030 | |
| 1031 | if (cpu >= num_possible_cpus()) { |
| 1032 | pr_err("Ignoring the CPU number in reboot= option. " |
| 1033 | "CPU %d exceeds possible cpu number %d\n", |
| 1034 | cpu, num_possible_cpus()); |
| 1035 | break; |
| 1036 | } |
| 1037 | reboot_cpu = cpu; |
| 1038 | } else |
| 1039 | *mode = REBOOT_SOFT; |
| 1040 | break; |
| 1041 | |
| 1042 | case 'g': |
| 1043 | *mode = REBOOT_GPIO; |
| 1044 | break; |
| 1045 | |
| 1046 | case 'b': |
| 1047 | case 'a': |
| 1048 | case 'k': |
| 1049 | case 't': |
| 1050 | case 'e': |
| 1051 | case 'p': |
| 1052 | reboot_type = *str; |
| 1053 | break; |
| 1054 | |
| 1055 | case 'f': |
| 1056 | reboot_force = 1; |
| 1057 | break; |
| 1058 | } |
| 1059 | |
| 1060 | str = strchr(str, ','); |
| 1061 | if (str) |
| 1062 | str++; |
| 1063 | else |
| 1064 | break; |
| 1065 | } |
| 1066 | return 1; |
| 1067 | } |
| 1068 | __setup("reboot=", reboot_setup); |
| 1069 | |
| 1070 | #ifdef CONFIG_SYSFS |
| 1071 | |
| 1072 | #define REBOOT_COLD_STR "cold" |
| 1073 | #define REBOOT_WARM_STR "warm" |
| 1074 | #define REBOOT_HARD_STR "hard" |
| 1075 | #define REBOOT_SOFT_STR "soft" |
| 1076 | #define REBOOT_GPIO_STR "gpio" |
| 1077 | #define REBOOT_UNDEFINED_STR "undefined" |
| 1078 | |
| 1079 | #define BOOT_TRIPLE_STR "triple" |
| 1080 | #define BOOT_KBD_STR "kbd" |
| 1081 | #define BOOT_BIOS_STR "bios" |
| 1082 | #define BOOT_ACPI_STR "acpi" |
| 1083 | #define BOOT_EFI_STR "efi" |
| 1084 | #define BOOT_PCI_STR "pci" |
| 1085 | |
| 1086 | static ssize_t mode_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) |
| 1087 | { |
| 1088 | const char *val; |
| 1089 | |
| 1090 | switch (reboot_mode) { |
| 1091 | case REBOOT_COLD: |
| 1092 | val = REBOOT_COLD_STR; |
| 1093 | break; |
| 1094 | case REBOOT_WARM: |
| 1095 | val = REBOOT_WARM_STR; |
| 1096 | break; |
| 1097 | case REBOOT_HARD: |
| 1098 | val = REBOOT_HARD_STR; |
| 1099 | break; |
| 1100 | case REBOOT_SOFT: |
| 1101 | val = REBOOT_SOFT_STR; |
| 1102 | break; |
| 1103 | case REBOOT_GPIO: |
| 1104 | val = REBOOT_GPIO_STR; |
| 1105 | break; |
| 1106 | default: |
| 1107 | val = REBOOT_UNDEFINED_STR; |
| 1108 | } |
| 1109 | |
| 1110 | return sprintf(buf, "%s\n", val); |
| 1111 | } |
| 1112 | static ssize_t mode_store(struct kobject *kobj, struct kobj_attribute *attr, |
| 1113 | const char *buf, size_t count) |
| 1114 | { |
| 1115 | if (!capable(CAP_SYS_BOOT)) |
| 1116 | return -EPERM; |
| 1117 | |
| 1118 | if (!strncmp(buf, REBOOT_COLD_STR, strlen(REBOOT_COLD_STR))) |
| 1119 | reboot_mode = REBOOT_COLD; |
| 1120 | else if (!strncmp(buf, REBOOT_WARM_STR, strlen(REBOOT_WARM_STR))) |
| 1121 | reboot_mode = REBOOT_WARM; |
| 1122 | else if (!strncmp(buf, REBOOT_HARD_STR, strlen(REBOOT_HARD_STR))) |
| 1123 | reboot_mode = REBOOT_HARD; |
| 1124 | else if (!strncmp(buf, REBOOT_SOFT_STR, strlen(REBOOT_SOFT_STR))) |
| 1125 | reboot_mode = REBOOT_SOFT; |
| 1126 | else if (!strncmp(buf, REBOOT_GPIO_STR, strlen(REBOOT_GPIO_STR))) |
| 1127 | reboot_mode = REBOOT_GPIO; |
| 1128 | else |
| 1129 | return -EINVAL; |
| 1130 | |
| 1131 | reboot_default = 0; |
| 1132 | |
| 1133 | return count; |
| 1134 | } |
| 1135 | static struct kobj_attribute reboot_mode_attr = __ATTR_RW(mode); |
| 1136 | |
| 1137 | #ifdef CONFIG_X86 |
| 1138 | static ssize_t force_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) |
| 1139 | { |
| 1140 | return sprintf(buf, "%d\n", reboot_force); |
| 1141 | } |
| 1142 | static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr, |
| 1143 | const char *buf, size_t count) |
| 1144 | { |
| 1145 | bool res; |
| 1146 | |
| 1147 | if (!capable(CAP_SYS_BOOT)) |
| 1148 | return -EPERM; |
| 1149 | |
| 1150 | if (kstrtobool(buf, &res)) |
| 1151 | return -EINVAL; |
| 1152 | |
| 1153 | reboot_default = 0; |
| 1154 | reboot_force = res; |
| 1155 | |
| 1156 | return count; |
| 1157 | } |
| 1158 | static struct kobj_attribute reboot_force_attr = __ATTR_RW(force); |
| 1159 | |
| 1160 | static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) |
| 1161 | { |
| 1162 | const char *val; |
| 1163 | |
| 1164 | switch (reboot_type) { |
| 1165 | case BOOT_TRIPLE: |
| 1166 | val = BOOT_TRIPLE_STR; |
| 1167 | break; |
| 1168 | case BOOT_KBD: |
| 1169 | val = BOOT_KBD_STR; |
| 1170 | break; |
| 1171 | case BOOT_BIOS: |
| 1172 | val = BOOT_BIOS_STR; |
| 1173 | break; |
| 1174 | case BOOT_ACPI: |
| 1175 | val = BOOT_ACPI_STR; |
| 1176 | break; |
| 1177 | case BOOT_EFI: |
| 1178 | val = BOOT_EFI_STR; |
| 1179 | break; |
| 1180 | case BOOT_CF9_FORCE: |
| 1181 | val = BOOT_PCI_STR; |
| 1182 | break; |
| 1183 | default: |
| 1184 | val = REBOOT_UNDEFINED_STR; |
| 1185 | } |
| 1186 | |
| 1187 | return sprintf(buf, "%s\n", val); |
| 1188 | } |
| 1189 | static ssize_t type_store(struct kobject *kobj, struct kobj_attribute *attr, |
| 1190 | const char *buf, size_t count) |
| 1191 | { |
| 1192 | if (!capable(CAP_SYS_BOOT)) |
| 1193 | return -EPERM; |
| 1194 | |
| 1195 | if (!strncmp(buf, BOOT_TRIPLE_STR, strlen(BOOT_TRIPLE_STR))) |
| 1196 | reboot_type = BOOT_TRIPLE; |
| 1197 | else if (!strncmp(buf, BOOT_KBD_STR, strlen(BOOT_KBD_STR))) |
| 1198 | reboot_type = BOOT_KBD; |
| 1199 | else if (!strncmp(buf, BOOT_BIOS_STR, strlen(BOOT_BIOS_STR))) |
| 1200 | reboot_type = BOOT_BIOS; |
| 1201 | else if (!strncmp(buf, BOOT_ACPI_STR, strlen(BOOT_ACPI_STR))) |
| 1202 | reboot_type = BOOT_ACPI; |
| 1203 | else if (!strncmp(buf, BOOT_EFI_STR, strlen(BOOT_EFI_STR))) |
| 1204 | reboot_type = BOOT_EFI; |
| 1205 | else if (!strncmp(buf, BOOT_PCI_STR, strlen(BOOT_PCI_STR))) |
| 1206 | reboot_type = BOOT_CF9_FORCE; |
| 1207 | else |
| 1208 | return -EINVAL; |
| 1209 | |
| 1210 | reboot_default = 0; |
| 1211 | |
| 1212 | return count; |
| 1213 | } |
| 1214 | static struct kobj_attribute reboot_type_attr = __ATTR_RW(type); |
| 1215 | #endif |
| 1216 | |
| 1217 | #ifdef CONFIG_SMP |
| 1218 | static ssize_t cpu_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) |
| 1219 | { |
| 1220 | return sprintf(buf, "%d\n", reboot_cpu); |
| 1221 | } |
| 1222 | static ssize_t cpu_store(struct kobject *kobj, struct kobj_attribute *attr, |
| 1223 | const char *buf, size_t count) |
| 1224 | { |
| 1225 | unsigned int cpunum; |
| 1226 | int rc; |
| 1227 | |
| 1228 | if (!capable(CAP_SYS_BOOT)) |
| 1229 | return -EPERM; |
| 1230 | |
| 1231 | rc = kstrtouint(buf, 0, &cpunum); |
| 1232 | |
| 1233 | if (rc) |
| 1234 | return rc; |
| 1235 | |
| 1236 | if (cpunum >= num_possible_cpus()) |
| 1237 | return -ERANGE; |
| 1238 | |
| 1239 | reboot_default = 0; |
| 1240 | reboot_cpu = cpunum; |
| 1241 | |
| 1242 | return count; |
| 1243 | } |
| 1244 | static struct kobj_attribute reboot_cpu_attr = __ATTR_RW(cpu); |
| 1245 | #endif |
| 1246 | |
| 1247 | static struct attribute *reboot_attrs[] = { |
| 1248 | &reboot_mode_attr.attr, |
| 1249 | #ifdef CONFIG_X86 |
| 1250 | &reboot_force_attr.attr, |
| 1251 | &reboot_type_attr.attr, |
| 1252 | #endif |
| 1253 | #ifdef CONFIG_SMP |
| 1254 | &reboot_cpu_attr.attr, |
| 1255 | #endif |
| 1256 | NULL, |
| 1257 | }; |
| 1258 | |
| 1259 | #ifdef CONFIG_SYSCTL |
| 1260 | static struct ctl_table kern_reboot_table[] = { |
| 1261 | { |
| 1262 | .procname = "poweroff_cmd", |
| 1263 | .data = &poweroff_cmd, |
| 1264 | .maxlen = POWEROFF_CMD_PATH_LEN, |
| 1265 | .mode = 0644, |
| 1266 | .proc_handler = proc_dostring, |
| 1267 | }, |
| 1268 | { |
| 1269 | .procname = "ctrl-alt-del", |
| 1270 | .data = &C_A_D, |
| 1271 | .maxlen = sizeof(int), |
| 1272 | .mode = 0644, |
| 1273 | .proc_handler = proc_dointvec, |
| 1274 | }, |
| 1275 | { } |
| 1276 | }; |
| 1277 | |
| 1278 | static void __init kernel_reboot_sysctls_init(void) |
| 1279 | { |
| 1280 | register_sysctl_init("kernel", kern_reboot_table); |
| 1281 | } |
| 1282 | #else |
| 1283 | #define kernel_reboot_sysctls_init() do { } while (0) |
| 1284 | #endif /* CONFIG_SYSCTL */ |
| 1285 | |
| 1286 | static const struct attribute_group reboot_attr_group = { |
| 1287 | .attrs = reboot_attrs, |
| 1288 | }; |
| 1289 | |
| 1290 | static int __init reboot_ksysfs_init(void) |
| 1291 | { |
| 1292 | struct kobject *reboot_kobj; |
| 1293 | int ret; |
| 1294 | |
| 1295 | reboot_kobj = kobject_create_and_add("reboot", kernel_kobj); |
| 1296 | if (!reboot_kobj) |
| 1297 | return -ENOMEM; |
| 1298 | |
| 1299 | ret = sysfs_create_group(reboot_kobj, &reboot_attr_group); |
| 1300 | if (ret) { |
| 1301 | kobject_put(reboot_kobj); |
| 1302 | return ret; |
| 1303 | } |
| 1304 | |
| 1305 | kernel_reboot_sysctls_init(); |
| 1306 | |
| 1307 | return 0; |
| 1308 | } |
| 1309 | late_initcall(reboot_ksysfs_init); |
| 1310 | |
| 1311 | #endif |