diff options
Diffstat (limited to 'kernel/reboot.c')
| -rw-r--r-- | kernel/reboot.c | 556 |
1 files changed, 540 insertions, 16 deletions
diff --git a/kernel/reboot.c b/kernel/reboot.c index eb1b15850761..b5a8569e5d81 100644 --- a/kernel/reboot.c +++ b/kernel/reboot.c @@ -7,6 +7,7 @@ #define pr_fmt(fmt) "reboot: " fmt +#include <linux/atomic.h> #include <linux/ctype.h> #include <linux/export.h> #include <linux/kexec.h> @@ -22,7 +23,7 @@ * 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); @@ -32,6 +33,7 @@ EXPORT_SYMBOL(cad_pid); #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; /* @@ -46,12 +48,36 @@ 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); -EXPORT_SYMBOL_GPL(pm_power_off_prepare); +/* + * 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 @@ -64,6 +90,7 @@ EXPORT_SYMBOL_GPL(pm_power_off_prepare); void emergency_restart(void) { kmsg_dump(KMSG_DUMP_EMERG); + system_state = SYSTEM_RESTART; machine_emergency_restart(); } EXPORT_SYMBOL_GPL(emergency_restart); @@ -233,6 +260,17 @@ 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 @@ -244,8 +282,7 @@ void migrate_to_reboot_cpu(void) void kernel_restart(char *cmd) { kernel_restart_prepare(cmd); - if (pm_power_off_prepare) - pm_power_off_prepare(); + do_kernel_restart_prepare(); migrate_to_reboot_cpu(); syscore_shutdown(); if (!cmd) @@ -275,12 +312,386 @@ void kernel_halt(void) kernel_shutdown_prepare(SYSTEM_HALT); migrate_to_reboot_cpu(); syscore_shutdown(); - pr_emerg("System halted\n"); + 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 * @@ -289,8 +700,7 @@ 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"); @@ -340,8 +750,10 @@ 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(&system_transition_mutex); switch (cmd) { @@ -360,7 +772,6 @@ 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(); @@ -418,7 +829,8 @@ 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 run_cmd(const char *cmd) @@ -520,6 +932,90 @@ void orderly_reboot(void) } EXPORT_SYMBOL_GPL(orderly_reboot); +/** + * hw_failure_emergency_poweroff_func - emergency poweroff work after a known delay + * @work: work_struct associated with the emergency poweroff function + * + * This function is called in very critical situations to force + * a kernel poweroff after a configurable timeout value. + */ +static void hw_failure_emergency_poweroff_func(struct work_struct *work) +{ + /* + * We have reached here after the emergency shutdown waiting period has + * expired. This means orderly_poweroff has not been able to shut off + * the system for some reason. + * + * Try to shut down the system immediately using kernel_power_off + * if populated + */ + pr_emerg("Hardware protection timed-out. Trying forced poweroff\n"); + kernel_power_off(); + + /* + * Worst of the worst case trigger emergency restart + */ + pr_emerg("Hardware protection shutdown failed. Trying emergency restart\n"); + emergency_restart(); +} + +static DECLARE_DELAYED_WORK(hw_failure_emergency_poweroff_work, + hw_failure_emergency_poweroff_func); + +/** + * hw_failure_emergency_poweroff - Trigger an emergency system poweroff + * + * This may be called from any critical situation to trigger a system shutdown + * after a given period of time. If time is negative this is not scheduled. + */ +static void hw_failure_emergency_poweroff(int poweroff_delay_ms) +{ + if (poweroff_delay_ms <= 0) + return; + schedule_delayed_work(&hw_failure_emergency_poweroff_work, + msecs_to_jiffies(poweroff_delay_ms)); +} + +/** + * __hw_protection_shutdown - 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. + * @shutdown: If true, indicates that a shutdown will happen + * after the critical tempeature is reached. + * If false, indicates that a reboot will happen + * after the critical tempeature is reached. + * + * 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_shutdown(const char *reason, int ms_until_forced, bool shutdown) +{ + static atomic_t allow_proceed = ATOMIC_INIT(1); + + pr_emerg("HARDWARE PROTECTION shutdown (%s)\n", 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_poweroff(ms_until_forced); + if (shutdown) + orderly_poweroff(true); + else + orderly_reboot(); +} +EXPORT_SYMBOL_GPL(__hw_protection_shutdown); + static int __init reboot_setup(char *str) { for (;;) { @@ -641,7 +1137,7 @@ static ssize_t mode_show(struct kobject *kobj, struct kobj_attribute *attr, char val = REBOOT_UNDEFINED_STR; } - return sprintf(buf, "%s\n", val); + 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) @@ -671,7 +1167,7 @@ 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 sprintf(buf, "%d\n", reboot_force); + 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) @@ -718,7 +1214,7 @@ static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr, char val = REBOOT_UNDEFINED_STR; } - return sprintf(buf, "%s\n", val); + 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) @@ -751,7 +1247,7 @@ static struct kobj_attribute reboot_type_attr = __ATTR_RW(type); #ifdef CONFIG_SMP static ssize_t cpu_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { - return sprintf(buf, "%d\n", reboot_cpu); + 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) @@ -790,6 +1286,32 @@ static struct attribute *reboot_attrs[] = { 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, }; @@ -809,6 +1331,8 @@ static int __init reboot_ksysfs_init(void) return ret; } + kernel_reboot_sysctls_init(); + return 0; } late_initcall(reboot_ksysfs_init); |