diff options
Diffstat (limited to 'kernel/reboot.c')
| -rw-r--r-- | kernel/reboot.c | 1070 |
1 files changed, 1035 insertions, 35 deletions
diff --git a/kernel/reboot.c b/kernel/reboot.c index 269ed9384cc4..ec087827c85c 100644 --- a/kernel/reboot.c +++ b/kernel/reboot.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * linux/kernel/reboot.c * @@ -6,6 +7,7 @@ #define pr_fmt(fmt) "reboot: " fmt +#include <linux/atomic.h> #include <linux/ctype.h> #include <linux/export.h> #include <linux/kexec.h> @@ -21,27 +23,63 @@ * this indicates whether you can reboot with ctrl-alt-del: the default is yes */ -int C_A_D = 1; +static int C_A_D = 1; struct pid *cad_pid; EXPORT_SYMBOL(cad_pid); -#if defined(CONFIG_ARM) || defined(CONFIG_UNICORE32) +#if defined(CONFIG_ARM) #define DEFAULT_REBOOT_MODE = REBOOT_HARD #else #define DEFAULT_REBOOT_MODE #endif enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE; +EXPORT_SYMBOL_GPL(reboot_mode); +enum reboot_mode panic_reboot_mode = REBOOT_UNDEFINED; -int reboot_default; +static enum hw_protection_action hw_protection_action = HWPROT_ACT_SHUTDOWN; + +/* + * This variable is used privately to keep track of whether or not + * reboot_type is still set to its default value (i.e., reboot= hasn't + * been set on the command line). This is needed so that we can + * suppress DMI scanning for reboot quirks. Without it, it's + * impossible to override a faulty reboot quirk without recompiling. + */ +int reboot_default = 1; int reboot_cpu; enum reboot_type reboot_type = BOOT_ACPI; int reboot_force; +struct sys_off_handler { + struct notifier_block nb; + int (*sys_off_cb)(struct sys_off_data *data); + void *cb_data; + enum sys_off_mode mode; + bool blocking; + void *list; + struct device *dev; +}; + /* - * If set, this is used for preparing the system to power off. + * This variable is used to indicate if a halt was initiated instead of a + * reboot when the reboot call was invoked with LINUX_REBOOT_CMD_POWER_OFF, but + * the system cannot be powered off. This allowes kernel_halt() to notify users + * of that. */ +static bool poweroff_fallback_to_halt; -void (*pm_power_off_prepare)(void); +/* + * Temporary stub that prevents linkage failure while we're in process + * of removing all uses of legacy pm_power_off() around the kernel. + */ +void __weak (*pm_power_off)(void); + +/* + * Notifier list for kernel code which wants to be called + * at shutdown. This is used to stop any idling DMA operations + * and the like. + */ +static BLOCKING_NOTIFIER_HEAD(reboot_notifier_list); /** * emergency_restart - reboot the system @@ -54,6 +92,7 @@ void (*pm_power_off_prepare)(void); void emergency_restart(void) { kmsg_dump(KMSG_DUMP_EMERG); + system_state = SYSTEM_RESTART; machine_emergency_restart(); } EXPORT_SYMBOL_GPL(emergency_restart); @@ -97,7 +136,118 @@ int unregister_reboot_notifier(struct notifier_block *nb) } EXPORT_SYMBOL(unregister_reboot_notifier); -static void migrate_to_reboot_cpu(void) +static void devm_unregister_reboot_notifier(struct device *dev, void *res) +{ + WARN_ON(unregister_reboot_notifier(*(struct notifier_block **)res)); +} + +int devm_register_reboot_notifier(struct device *dev, struct notifier_block *nb) +{ + struct notifier_block **rcnb; + int ret; + + rcnb = devres_alloc(devm_unregister_reboot_notifier, + sizeof(*rcnb), GFP_KERNEL); + if (!rcnb) + return -ENOMEM; + + ret = register_reboot_notifier(nb); + if (!ret) { + *rcnb = nb; + devres_add(dev, rcnb); + } else { + devres_free(rcnb); + } + + return ret; +} +EXPORT_SYMBOL(devm_register_reboot_notifier); + +/* + * Notifier list for kernel code which wants to be called + * to restart the system. + */ +static ATOMIC_NOTIFIER_HEAD(restart_handler_list); + +/** + * register_restart_handler - Register function to be called to reset + * the system + * @nb: Info about handler function to be called + * @nb->priority: Handler priority. Handlers should follow the + * following guidelines for setting priorities. + * 0: Restart handler of last resort, + * with limited restart capabilities + * 128: Default restart handler; use if no other + * restart handler is expected to be available, + * and/or if restart functionality is + * sufficient to restart the entire system + * 255: Highest priority restart handler, will + * preempt all other restart handlers + * + * Registers a function with code to be called to restart the + * system. + * + * Registered functions will be called from machine_restart as last + * step of the restart sequence (if the architecture specific + * machine_restart function calls do_kernel_restart - see below + * for details). + * Registered functions are expected to restart the system immediately. + * If more than one function is registered, the restart handler priority + * selects which function will be called first. + * + * Restart handlers are expected to be registered from non-architecture + * code, typically from drivers. A typical use case would be a system + * where restart functionality is provided through a watchdog. Multiple + * restart handlers may exist; for example, one restart handler might + * restart the entire system, while another only restarts the CPU. + * In such cases, the restart handler which only restarts part of the + * hardware is expected to register with low priority to ensure that + * it only runs if no other means to restart the system is available. + * + * Currently always returns zero, as atomic_notifier_chain_register() + * always returns zero. + */ +int register_restart_handler(struct notifier_block *nb) +{ + return atomic_notifier_chain_register(&restart_handler_list, nb); +} +EXPORT_SYMBOL(register_restart_handler); + +/** + * unregister_restart_handler - Unregister previously registered + * restart handler + * @nb: Hook to be unregistered + * + * Unregisters a previously registered restart handler function. + * + * Returns zero on success, or %-ENOENT on failure. + */ +int unregister_restart_handler(struct notifier_block *nb) +{ + return atomic_notifier_chain_unregister(&restart_handler_list, nb); +} +EXPORT_SYMBOL(unregister_restart_handler); + +/** + * do_kernel_restart - Execute kernel restart handler call chain + * + * @cmd: pointer to buffer containing command to execute for restart + * or %NULL + * + * Calls functions registered with register_restart_handler. + * + * Expected to be called from machine_restart as last step of the restart + * sequence. + * + * Restarts the system immediately if a restart handler function has been + * registered. Otherwise does nothing. + */ +void do_kernel_restart(char *cmd) +{ + atomic_notifier_call_chain(&restart_handler_list, reboot_mode, cmd); +} + +void migrate_to_reboot_cpu(void) { /* The boot cpu is always logical cpu 0 */ int cpu = reboot_cpu; @@ -115,6 +265,17 @@ static void migrate_to_reboot_cpu(void) set_cpus_allowed_ptr(current, cpumask_of(cpu)); } +/* + * Notifier list for kernel code which wants to be called + * to prepare system for restart. + */ +static BLOCKING_NOTIFIER_HEAD(restart_prep_handler_list); + +static void do_kernel_restart_prepare(void) +{ + blocking_notifier_call_chain(&restart_prep_handler_list, 0, NULL); +} + /** * kernel_restart - reboot the system * @cmd: pointer to buffer containing command to execute for restart @@ -126,13 +287,14 @@ static void migrate_to_reboot_cpu(void) void kernel_restart(char *cmd) { kernel_restart_prepare(cmd); + do_kernel_restart_prepare(); migrate_to_reboot_cpu(); syscore_shutdown(); if (!cmd) pr_emerg("Restarting system\n"); else pr_emerg("Restarting system with command '%s'\n", cmd); - kmsg_dump(KMSG_DUMP_RESTART); + kmsg_dump(KMSG_DUMP_SHUTDOWN); machine_restart(cmd); } EXPORT_SYMBOL_GPL(kernel_restart); @@ -155,12 +317,386 @@ void kernel_halt(void) kernel_shutdown_prepare(SYSTEM_HALT); migrate_to_reboot_cpu(); syscore_shutdown(); - pr_emerg("System halted\n"); - kmsg_dump(KMSG_DUMP_HALT); + if (poweroff_fallback_to_halt) + pr_emerg("Power off not available: System halted instead\n"); + else + pr_emerg("System halted\n"); + kmsg_dump(KMSG_DUMP_SHUTDOWN); machine_halt(); } EXPORT_SYMBOL_GPL(kernel_halt); +/* + * Notifier list for kernel code which wants to be called + * to prepare system for power off. + */ +static BLOCKING_NOTIFIER_HEAD(power_off_prep_handler_list); + +/* + * Notifier list for kernel code which wants to be called + * to power off system. + */ +static ATOMIC_NOTIFIER_HEAD(power_off_handler_list); + +static int sys_off_notify(struct notifier_block *nb, + unsigned long mode, void *cmd) +{ + struct sys_off_handler *handler; + struct sys_off_data data = {}; + + handler = container_of(nb, struct sys_off_handler, nb); + data.cb_data = handler->cb_data; + data.mode = mode; + data.cmd = cmd; + data.dev = handler->dev; + + return handler->sys_off_cb(&data); +} + +static struct sys_off_handler platform_sys_off_handler; + +static struct sys_off_handler *alloc_sys_off_handler(int priority) +{ + struct sys_off_handler *handler; + gfp_t flags; + + /* + * Platforms like m68k can't allocate sys_off handler dynamically + * at the early boot time because memory allocator isn't available yet. + */ + if (priority == SYS_OFF_PRIO_PLATFORM) { + handler = &platform_sys_off_handler; + if (handler->cb_data) + return ERR_PTR(-EBUSY); + } else { + if (system_state > SYSTEM_RUNNING) + flags = GFP_ATOMIC; + else + flags = GFP_KERNEL; + + handler = kzalloc(sizeof(*handler), flags); + if (!handler) + return ERR_PTR(-ENOMEM); + } + + return handler; +} + +static void free_sys_off_handler(struct sys_off_handler *handler) +{ + if (handler == &platform_sys_off_handler) + memset(handler, 0, sizeof(*handler)); + else + kfree(handler); +} + +/** + * register_sys_off_handler - Register sys-off handler + * @mode: Sys-off mode + * @priority: Handler priority + * @callback: Callback function + * @cb_data: Callback argument + * + * Registers system power-off or restart handler that will be invoked + * at the step corresponding to the given sys-off mode. Handler's callback + * should return NOTIFY_DONE to permit execution of the next handler in + * the call chain or NOTIFY_STOP to break the chain (in error case for + * example). + * + * Multiple handlers can be registered at the default priority level. + * + * Only one handler can be registered at the non-default priority level, + * otherwise ERR_PTR(-EBUSY) is returned. + * + * Returns a new instance of struct sys_off_handler on success, or + * an ERR_PTR()-encoded error code otherwise. + */ +struct sys_off_handler * +register_sys_off_handler(enum sys_off_mode mode, + int priority, + int (*callback)(struct sys_off_data *data), + void *cb_data) +{ + struct sys_off_handler *handler; + int err; + + handler = alloc_sys_off_handler(priority); + if (IS_ERR(handler)) + return handler; + + switch (mode) { + case SYS_OFF_MODE_POWER_OFF_PREPARE: + handler->list = &power_off_prep_handler_list; + handler->blocking = true; + break; + + case SYS_OFF_MODE_POWER_OFF: + handler->list = &power_off_handler_list; + break; + + case SYS_OFF_MODE_RESTART_PREPARE: + handler->list = &restart_prep_handler_list; + handler->blocking = true; + break; + + case SYS_OFF_MODE_RESTART: + handler->list = &restart_handler_list; + break; + + default: + free_sys_off_handler(handler); + return ERR_PTR(-EINVAL); + } + + handler->nb.notifier_call = sys_off_notify; + handler->nb.priority = priority; + handler->sys_off_cb = callback; + handler->cb_data = cb_data; + handler->mode = mode; + + if (handler->blocking) { + if (priority == SYS_OFF_PRIO_DEFAULT) + err = blocking_notifier_chain_register(handler->list, + &handler->nb); + else + err = blocking_notifier_chain_register_unique_prio(handler->list, + &handler->nb); + } else { + if (priority == SYS_OFF_PRIO_DEFAULT) + err = atomic_notifier_chain_register(handler->list, + &handler->nb); + else + err = atomic_notifier_chain_register_unique_prio(handler->list, + &handler->nb); + } + + if (err) { + free_sys_off_handler(handler); + return ERR_PTR(err); + } + + return handler; +} +EXPORT_SYMBOL_GPL(register_sys_off_handler); + +/** + * unregister_sys_off_handler - Unregister sys-off handler + * @handler: Sys-off handler + * + * Unregisters given sys-off handler. + */ +void unregister_sys_off_handler(struct sys_off_handler *handler) +{ + int err; + + if (IS_ERR_OR_NULL(handler)) + return; + + if (handler->blocking) + err = blocking_notifier_chain_unregister(handler->list, + &handler->nb); + else + err = atomic_notifier_chain_unregister(handler->list, + &handler->nb); + + /* sanity check, shall never happen */ + WARN_ON(err); + + free_sys_off_handler(handler); +} +EXPORT_SYMBOL_GPL(unregister_sys_off_handler); + +static void devm_unregister_sys_off_handler(void *data) +{ + struct sys_off_handler *handler = data; + + unregister_sys_off_handler(handler); +} + +/** + * devm_register_sys_off_handler - Register sys-off handler + * @dev: Device that registers handler + * @mode: Sys-off mode + * @priority: Handler priority + * @callback: Callback function + * @cb_data: Callback argument + * + * Registers resource-managed sys-off handler. + * + * Returns zero on success, or error code on failure. + */ +int devm_register_sys_off_handler(struct device *dev, + enum sys_off_mode mode, + int priority, + int (*callback)(struct sys_off_data *data), + void *cb_data) +{ + struct sys_off_handler *handler; + + handler = register_sys_off_handler(mode, priority, callback, cb_data); + if (IS_ERR(handler)) + return PTR_ERR(handler); + handler->dev = dev; + + return devm_add_action_or_reset(dev, devm_unregister_sys_off_handler, + handler); +} +EXPORT_SYMBOL_GPL(devm_register_sys_off_handler); + +/** + * devm_register_power_off_handler - Register power-off handler + * @dev: Device that registers callback + * @callback: Callback function + * @cb_data: Callback's argument + * + * Registers resource-managed sys-off handler with a default priority + * and using power-off mode. + * + * Returns zero on success, or error code on failure. + */ +int devm_register_power_off_handler(struct device *dev, + int (*callback)(struct sys_off_data *data), + void *cb_data) +{ + return devm_register_sys_off_handler(dev, + SYS_OFF_MODE_POWER_OFF, + SYS_OFF_PRIO_DEFAULT, + callback, cb_data); +} +EXPORT_SYMBOL_GPL(devm_register_power_off_handler); + +/** + * devm_register_restart_handler - Register restart handler + * @dev: Device that registers callback + * @callback: Callback function + * @cb_data: Callback's argument + * + * Registers resource-managed sys-off handler with a default priority + * and using restart mode. + * + * Returns zero on success, or error code on failure. + */ +int devm_register_restart_handler(struct device *dev, + int (*callback)(struct sys_off_data *data), + void *cb_data) +{ + return devm_register_sys_off_handler(dev, + SYS_OFF_MODE_RESTART, + SYS_OFF_PRIO_DEFAULT, + callback, cb_data); +} +EXPORT_SYMBOL_GPL(devm_register_restart_handler); + +static struct sys_off_handler *platform_power_off_handler; + +static int platform_power_off_notify(struct sys_off_data *data) +{ + void (*platform_power_power_off_cb)(void) = data->cb_data; + + platform_power_power_off_cb(); + + return NOTIFY_DONE; +} + +/** + * register_platform_power_off - Register platform-level power-off callback + * @power_off: Power-off callback + * + * Registers power-off callback that will be called as last step + * of the power-off sequence. This callback is expected to be invoked + * for the last resort. Only one platform power-off callback is allowed + * to be registered at a time. + * + * Returns zero on success, or error code on failure. + */ +int register_platform_power_off(void (*power_off)(void)) +{ + struct sys_off_handler *handler; + + handler = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, + SYS_OFF_PRIO_PLATFORM, + platform_power_off_notify, + power_off); + if (IS_ERR(handler)) + return PTR_ERR(handler); + + platform_power_off_handler = handler; + + return 0; +} +EXPORT_SYMBOL_GPL(register_platform_power_off); + +/** + * unregister_platform_power_off - Unregister platform-level power-off callback + * @power_off: Power-off callback + * + * Unregisters previously registered platform power-off callback. + */ +void unregister_platform_power_off(void (*power_off)(void)) +{ + if (platform_power_off_handler && + platform_power_off_handler->cb_data == power_off) { + unregister_sys_off_handler(platform_power_off_handler); + platform_power_off_handler = NULL; + } +} +EXPORT_SYMBOL_GPL(unregister_platform_power_off); + +static int legacy_pm_power_off(struct sys_off_data *data) +{ + if (pm_power_off) + pm_power_off(); + + return NOTIFY_DONE; +} + +static void do_kernel_power_off_prepare(void) +{ + blocking_notifier_call_chain(&power_off_prep_handler_list, 0, NULL); +} + +/** + * do_kernel_power_off - Execute kernel power-off handler call chain + * + * Expected to be called as last step of the power-off sequence. + * + * Powers off the system immediately if a power-off handler function has + * been registered. Otherwise does nothing. + */ +void do_kernel_power_off(void) +{ + struct sys_off_handler *sys_off = NULL; + + /* + * Register sys-off handlers for legacy PM callback. This allows + * legacy PM callbacks temporary co-exist with the new sys-off API. + * + * TODO: Remove legacy handlers once all legacy PM users will be + * switched to the sys-off based APIs. + */ + if (pm_power_off) + sys_off = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, + SYS_OFF_PRIO_DEFAULT, + legacy_pm_power_off, NULL); + + atomic_notifier_call_chain(&power_off_handler_list, 0, NULL); + + unregister_sys_off_handler(sys_off); +} + +/** + * kernel_can_power_off - check whether system can be powered off + * + * Returns true if power-off handler is registered and system can be + * powered off, false otherwise. + */ +bool kernel_can_power_off(void) +{ + return !atomic_notifier_call_chain_is_empty(&power_off_handler_list) || + pm_power_off; +} +EXPORT_SYMBOL_GPL(kernel_can_power_off); + /** * kernel_power_off - power_off the system * @@ -169,17 +705,17 @@ EXPORT_SYMBOL_GPL(kernel_halt); void kernel_power_off(void) { kernel_shutdown_prepare(SYSTEM_POWER_OFF); - if (pm_power_off_prepare) - pm_power_off_prepare(); + do_kernel_power_off_prepare(); migrate_to_reboot_cpu(); syscore_shutdown(); pr_emerg("Power down\n"); - kmsg_dump(KMSG_DUMP_POWEROFF); + pr_flush(1000, true); + kmsg_dump(KMSG_DUMP_SHUTDOWN); machine_power_off(); } EXPORT_SYMBOL_GPL(kernel_power_off); -static DEFINE_MUTEX(reboot_mutex); +DEFINE_MUTEX(system_transition_mutex); /* * Reboot system call: for obvious reasons only root may call it, @@ -220,10 +756,12 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, /* Instead of trying to make the power_off code look like * halt when pm_power_off is not set do it the easy way. */ - if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off) + if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !kernel_can_power_off()) { + poweroff_fallback_to_halt = true; cmd = LINUX_REBOOT_CMD_HALT; + } - mutex_lock(&reboot_mutex); + mutex_lock(&system_transition_mutex); switch (cmd) { case LINUX_REBOOT_CMD_RESTART: kernel_restart(NULL); @@ -240,7 +778,6 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, case LINUX_REBOOT_CMD_HALT: kernel_halt(); do_exit(0); - panic("cannot halt"); case LINUX_REBOOT_CMD_POWER_OFF: kernel_power_off(); @@ -258,7 +795,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, kernel_restart(buffer); break; -#ifdef CONFIG_KEXEC +#ifdef CONFIG_KEXEC_CORE case LINUX_REBOOT_CMD_KEXEC: ret = kernel_kexec(); break; @@ -274,7 +811,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, ret = -EINVAL; break; } - mutex_unlock(&reboot_mutex); + mutex_unlock(&system_transition_mutex); return ret; } @@ -298,9 +835,11 @@ void ctrl_alt_del(void) kill_cad_pid(SIGINT, 1); } -char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff"; +#define POWEROFF_CMD_PATH_LEN 256 +static char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff"; +static const char reboot_cmd[] = "/sbin/reboot"; -static int __orderly_poweroff(bool force) +static int run_cmd(const char *cmd) { char **argv; static char *envp[] = { @@ -309,8 +848,7 @@ static int __orderly_poweroff(bool force) NULL }; int ret; - - argv = argv_split(GFP_KERNEL, poweroff_cmd, NULL); + argv = argv_split(GFP_KERNEL, cmd, NULL); if (argv) { ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC); argv_free(argv); @@ -318,8 +856,33 @@ static int __orderly_poweroff(bool force) ret = -ENOMEM; } + return ret; +} + +static int __orderly_reboot(void) +{ + int ret; + + ret = run_cmd(reboot_cmd); + + if (ret) { + pr_warn("Failed to start orderly reboot: forcing the issue\n"); + emergency_sync(); + kernel_restart(NULL); + } + + return ret; +} + +static int __orderly_poweroff(bool force) +{ + int ret; + + ret = run_cmd(poweroff_cmd); + if (ret && force) { pr_warn("Failed to start orderly shutdown: forcing the issue\n"); + /* * I guess this should try to kick off some daemon to sync and * poweroff asap. Or not even bother syncing if we're doing an @@ -348,18 +911,194 @@ static DECLARE_WORK(poweroff_work, poweroff_work_func); * This may be called from any context to trigger a system shutdown. * If the orderly shutdown fails, it will force an immediate shutdown. */ -int orderly_poweroff(bool force) +void orderly_poweroff(bool force) { if (force) /* do not override the pending "true" */ poweroff_force = true; schedule_work(&poweroff_work); - return 0; } EXPORT_SYMBOL_GPL(orderly_poweroff); +static void reboot_work_func(struct work_struct *work) +{ + __orderly_reboot(); +} + +static DECLARE_WORK(reboot_work, reboot_work_func); + +/** + * orderly_reboot - Trigger an orderly system reboot + * + * This may be called from any context to trigger a system reboot. + * If the orderly reboot fails, it will force an immediate reboot. + */ +void orderly_reboot(void) +{ + schedule_work(&reboot_work); +} +EXPORT_SYMBOL_GPL(orderly_reboot); + +static const char *hw_protection_action_str(enum hw_protection_action action) +{ + switch (action) { + case HWPROT_ACT_SHUTDOWN: + return "shutdown"; + case HWPROT_ACT_REBOOT: + return "reboot"; + default: + return "undefined"; + } +} + +static enum hw_protection_action hw_failure_emergency_action; + +/** + * hw_failure_emergency_action_func - emergency action work after a known delay + * @work: work_struct associated with the emergency action function + * + * This function is called in very critical situations to force + * a kernel poweroff or reboot after a configurable timeout value. + */ +static void hw_failure_emergency_action_func(struct work_struct *work) +{ + const char *action_str = hw_protection_action_str(hw_failure_emergency_action); + + pr_emerg("Hardware protection timed-out. Trying forced %s\n", + action_str); + + /* + * We have reached here after the emergency action waiting period has + * expired. This means orderly_poweroff/reboot has not been able to + * shut off the system for some reason. + * + * Try to shut off the system immediately if possible + */ + + if (hw_failure_emergency_action == HWPROT_ACT_REBOOT) + kernel_restart(NULL); + else + kernel_power_off(); + + /* + * Worst of the worst case trigger emergency restart + */ + pr_emerg("Hardware protection %s failed. Trying emergency restart\n", + action_str); + emergency_restart(); +} + +static DECLARE_DELAYED_WORK(hw_failure_emergency_action_work, + hw_failure_emergency_action_func); + +/** + * hw_failure_emergency_schedule - Schedule an emergency system shutdown or reboot + * + * @action: The hardware protection action to be taken + * @action_delay_ms: Time in milliseconds to elapse before triggering action + * + * This may be called from any critical situation to trigger a system shutdown + * or reboot after a given period of time. + * If time is negative this is not scheduled. + */ +static void hw_failure_emergency_schedule(enum hw_protection_action action, + int action_delay_ms) +{ + if (action_delay_ms <= 0) + return; + hw_failure_emergency_action = action; + schedule_delayed_work(&hw_failure_emergency_action_work, + msecs_to_jiffies(action_delay_ms)); +} + +/** + * __hw_protection_trigger - Trigger an emergency system shutdown or reboot + * + * @reason: Reason of emergency shutdown or reboot to be printed. + * @ms_until_forced: Time to wait for orderly shutdown or reboot before + * triggering it. Negative value disables the forced + * shutdown or reboot. + * @action: The hardware protection action to be taken. + * + * Initiate an emergency system shutdown or reboot in order to protect + * hardware from further damage. Usage examples include a thermal protection. + * NOTE: The request is ignored if protection shutdown or reboot is already + * pending even if the previous request has given a large timeout for forced + * shutdown/reboot. + */ +void __hw_protection_trigger(const char *reason, int ms_until_forced, + enum hw_protection_action action) +{ + static atomic_t allow_proceed = ATOMIC_INIT(1); + + if (action == HWPROT_ACT_DEFAULT) + action = hw_protection_action; + + pr_emerg("HARDWARE PROTECTION %s (%s)\n", + hw_protection_action_str(action), reason); + + /* Shutdown should be initiated only once. */ + if (!atomic_dec_and_test(&allow_proceed)) + return; + + /* + * Queue a backup emergency shutdown in the event of + * orderly_poweroff failure + */ + hw_failure_emergency_schedule(action, ms_until_forced); + if (action == HWPROT_ACT_REBOOT) + orderly_reboot(); + else + orderly_poweroff(true); +} +EXPORT_SYMBOL_GPL(__hw_protection_trigger); + +static bool hw_protection_action_parse(const char *str, + enum hw_protection_action *action) +{ + if (sysfs_streq(str, "shutdown")) + *action = HWPROT_ACT_SHUTDOWN; + else if (sysfs_streq(str, "reboot")) + *action = HWPROT_ACT_REBOOT; + else + return false; + + return true; +} + +static int __init hw_protection_setup(char *str) +{ + hw_protection_action_parse(str, &hw_protection_action); + return 1; +} +__setup("hw_protection=", hw_protection_setup); + +#ifdef CONFIG_SYSFS +static ssize_t hw_protection_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%s\n", + hw_protection_action_str(hw_protection_action)); +} +static ssize_t hw_protection_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, + size_t count) +{ + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (!hw_protection_action_parse(buf, &hw_protection_action)) + return -EINVAL; + + return count; +} +static struct kobj_attribute hw_protection_attr = __ATTR_RW(hw_protection); +#endif + static int __init reboot_setup(char *str) { for (;;) { + enum reboot_mode *mode; + /* * Having anything passed on the command line via * reboot= will cause us to disable DMI checking @@ -367,31 +1106,49 @@ static int __init reboot_setup(char *str) */ reboot_default = 0; + if (!strncmp(str, "panic_", 6)) { + mode = &panic_reboot_mode; + str += 6; + } else { + mode = &reboot_mode; + } + switch (*str) { case 'w': - reboot_mode = REBOOT_WARM; + *mode = REBOOT_WARM; break; case 'c': - reboot_mode = REBOOT_COLD; + *mode = REBOOT_COLD; break; case 'h': - reboot_mode = REBOOT_HARD; + *mode = REBOOT_HARD; break; case 's': - if (isdigit(*(str+1))) - reboot_cpu = simple_strtoul(str+1, NULL, 0); - else if (str[1] == 'm' && str[2] == 'p' && - isdigit(*(str+3))) - reboot_cpu = simple_strtoul(str+3, NULL, 0); - else - reboot_mode = REBOOT_SOFT; + /* + * reboot_cpu is s[mp]#### with #### being the processor + * to be used for rebooting. Skip 's' or 'smp' prefix. + */ + str += str[1] == 'm' && str[2] == 'p' ? 3 : 1; + + if (isdigit(str[0])) { + int cpu = simple_strtoul(str, NULL, 0); + + if (cpu >= num_possible_cpus()) { + pr_err("Ignoring the CPU number in reboot= option. " + "CPU %d exceeds possible cpu number %d\n", + cpu, num_possible_cpus()); + break; + } + reboot_cpu = cpu; + } else + *mode = REBOOT_SOFT; break; case 'g': - reboot_mode = REBOOT_GPIO; + *mode = REBOOT_GPIO; break; case 'b': @@ -417,3 +1174,246 @@ static int __init reboot_setup(char *str) return 1; } __setup("reboot=", reboot_setup); + +#ifdef CONFIG_SYSFS + +#define REBOOT_COLD_STR "cold" +#define REBOOT_WARM_STR "warm" +#define REBOOT_HARD_STR "hard" +#define REBOOT_SOFT_STR "soft" +#define REBOOT_GPIO_STR "gpio" +#define REBOOT_UNDEFINED_STR "undefined" + +#define BOOT_TRIPLE_STR "triple" +#define BOOT_KBD_STR "kbd" +#define BOOT_BIOS_STR "bios" +#define BOOT_ACPI_STR "acpi" +#define BOOT_EFI_STR "efi" +#define BOOT_PCI_STR "pci" + +static ssize_t mode_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) +{ + const char *val; + + switch (reboot_mode) { + case REBOOT_COLD: + val = REBOOT_COLD_STR; + break; + case REBOOT_WARM: + val = REBOOT_WARM_STR; + break; + case REBOOT_HARD: + val = REBOOT_HARD_STR; + break; + case REBOOT_SOFT: + val = REBOOT_SOFT_STR; + break; + case REBOOT_GPIO: + val = REBOOT_GPIO_STR; + break; + default: + val = REBOOT_UNDEFINED_STR; + } + + return sysfs_emit(buf, "%s\n", val); +} +static ssize_t mode_store(struct kobject *kobj, struct kobj_attribute *attr, + const char *buf, size_t count) +{ + if (!capable(CAP_SYS_BOOT)) + return -EPERM; + + if (!strncmp(buf, REBOOT_COLD_STR, strlen(REBOOT_COLD_STR))) + reboot_mode = REBOOT_COLD; + else if (!strncmp(buf, REBOOT_WARM_STR, strlen(REBOOT_WARM_STR))) + reboot_mode = REBOOT_WARM; + else if (!strncmp(buf, REBOOT_HARD_STR, strlen(REBOOT_HARD_STR))) + reboot_mode = REBOOT_HARD; + else if (!strncmp(buf, REBOOT_SOFT_STR, strlen(REBOOT_SOFT_STR))) + reboot_mode = REBOOT_SOFT; + else if (!strncmp(buf, REBOOT_GPIO_STR, strlen(REBOOT_GPIO_STR))) + reboot_mode = REBOOT_GPIO; + else + return -EINVAL; + + reboot_default = 0; + + return count; +} +static struct kobj_attribute reboot_mode_attr = __ATTR_RW(mode); + +#ifdef CONFIG_X86 +static ssize_t force_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%d\n", reboot_force); +} +static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr, + const char *buf, size_t count) +{ + bool res; + + if (!capable(CAP_SYS_BOOT)) + return -EPERM; + + if (kstrtobool(buf, &res)) + return -EINVAL; + + reboot_default = 0; + reboot_force = res; + + return count; +} +static struct kobj_attribute reboot_force_attr = __ATTR_RW(force); + +static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) +{ + const char *val; + + switch (reboot_type) { + case BOOT_TRIPLE: + val = BOOT_TRIPLE_STR; + break; + case BOOT_KBD: + val = BOOT_KBD_STR; + break; + case BOOT_BIOS: + val = BOOT_BIOS_STR; + break; + case BOOT_ACPI: + val = BOOT_ACPI_STR; + break; + case BOOT_EFI: + val = BOOT_EFI_STR; + break; + case BOOT_CF9_FORCE: + val = BOOT_PCI_STR; + break; + default: + val = REBOOT_UNDEFINED_STR; + } + + return sysfs_emit(buf, "%s\n", val); +} +static ssize_t type_store(struct kobject *kobj, struct kobj_attribute *attr, + const char *buf, size_t count) +{ + if (!capable(CAP_SYS_BOOT)) + return -EPERM; + + if (!strncmp(buf, BOOT_TRIPLE_STR, strlen(BOOT_TRIPLE_STR))) + reboot_type = BOOT_TRIPLE; + else if (!strncmp(buf, BOOT_KBD_STR, strlen(BOOT_KBD_STR))) + reboot_type = BOOT_KBD; + else if (!strncmp(buf, BOOT_BIOS_STR, strlen(BOOT_BIOS_STR))) + reboot_type = BOOT_BIOS; + else if (!strncmp(buf, BOOT_ACPI_STR, strlen(BOOT_ACPI_STR))) + reboot_type = BOOT_ACPI; + else if (!strncmp(buf, BOOT_EFI_STR, strlen(BOOT_EFI_STR))) + reboot_type = BOOT_EFI; + else if (!strncmp(buf, BOOT_PCI_STR, strlen(BOOT_PCI_STR))) + reboot_type = BOOT_CF9_FORCE; + else + return -EINVAL; + + reboot_default = 0; + + return count; +} +static struct kobj_attribute reboot_type_attr = __ATTR_RW(type); +#endif + +#ifdef CONFIG_SMP +static ssize_t cpu_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%d\n", reboot_cpu); +} +static ssize_t cpu_store(struct kobject *kobj, struct kobj_attribute *attr, + const char *buf, size_t count) +{ + unsigned int cpunum; + int rc; + + if (!capable(CAP_SYS_BOOT)) + return -EPERM; + + rc = kstrtouint(buf, 0, &cpunum); + + if (rc) + return rc; + + if (cpunum >= num_possible_cpus()) + return -ERANGE; + + reboot_default = 0; + reboot_cpu = cpunum; + + return count; +} +static struct kobj_attribute reboot_cpu_attr = __ATTR_RW(cpu); +#endif + +static struct attribute *reboot_attrs[] = { + &hw_protection_attr.attr, + &reboot_mode_attr.attr, +#ifdef CONFIG_X86 + &reboot_force_attr.attr, + &reboot_type_attr.attr, +#endif +#ifdef CONFIG_SMP + &reboot_cpu_attr.attr, +#endif + NULL, +}; + +#ifdef CONFIG_SYSCTL +static const struct ctl_table kern_reboot_table[] = { + { + .procname = "poweroff_cmd", + .data = &poweroff_cmd, + .maxlen = POWEROFF_CMD_PATH_LEN, + .mode = 0644, + .proc_handler = proc_dostring, + }, + { + .procname = "ctrl-alt-del", + .data = &C_A_D, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, +}; + +static void __init kernel_reboot_sysctls_init(void) +{ + register_sysctl_init("kernel", kern_reboot_table); +} +#else +#define kernel_reboot_sysctls_init() do { } while (0) +#endif /* CONFIG_SYSCTL */ + +static const struct attribute_group reboot_attr_group = { + .attrs = reboot_attrs, +}; + +static int __init reboot_ksysfs_init(void) +{ + struct kobject *reboot_kobj; + int ret; + + reboot_kobj = kobject_create_and_add("reboot", kernel_kobj); + if (!reboot_kobj) + return -ENOMEM; + + ret = sysfs_create_group(reboot_kobj, &reboot_attr_group); + if (ret) { + kobject_put(reboot_kobj); + return ret; + } + + kernel_reboot_sysctls_init(); + + return 0; +} +late_initcall(reboot_ksysfs_init); + +#endif |