diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/notifier.c | 101 | ||||
| -rw-r--r-- | kernel/reboot.c | 347 |
2 files changed, 422 insertions, 26 deletions
diff --git a/kernel/notifier.c b/kernel/notifier.c index ba005ebf4730..0d5bd62c480e 100644 --- a/kernel/notifier.c +++ b/kernel/notifier.c @@ -20,7 +20,8 @@ BLOCKING_NOTIFIER_HEAD(reboot_notifier_list); */ static int notifier_chain_register(struct notifier_block **nl, - struct notifier_block *n) + struct notifier_block *n, + bool unique_priority) { while ((*nl) != NULL) { if (unlikely((*nl) == n)) { @@ -30,6 +31,8 @@ static int notifier_chain_register(struct notifier_block **nl, } if (n->priority > (*nl)->priority) break; + if (n->priority == (*nl)->priority && unique_priority) + return -EBUSY; nl = &((*nl)->next); } n->next = *nl; @@ -144,13 +147,36 @@ int atomic_notifier_chain_register(struct atomic_notifier_head *nh, int ret; spin_lock_irqsave(&nh->lock, flags); - ret = notifier_chain_register(&nh->head, n); + ret = notifier_chain_register(&nh->head, n, false); spin_unlock_irqrestore(&nh->lock, flags); return ret; } EXPORT_SYMBOL_GPL(atomic_notifier_chain_register); /** + * atomic_notifier_chain_register_unique_prio - Add notifier to an atomic notifier chain + * @nh: Pointer to head of the atomic notifier chain + * @n: New entry in notifier chain + * + * Adds a notifier to an atomic notifier chain if there is no other + * notifier registered using the same priority. + * + * Returns 0 on success, %-EEXIST or %-EBUSY on error. + */ +int atomic_notifier_chain_register_unique_prio(struct atomic_notifier_head *nh, + struct notifier_block *n) +{ + unsigned long flags; + int ret; + + spin_lock_irqsave(&nh->lock, flags); + ret = notifier_chain_register(&nh->head, n, true); + spin_unlock_irqrestore(&nh->lock, flags); + return ret; +} +EXPORT_SYMBOL_GPL(atomic_notifier_chain_register_unique_prio); + +/** * atomic_notifier_chain_unregister - Remove notifier from an atomic notifier chain * @nh: Pointer to head of the atomic notifier chain * @n: Entry to remove from notifier chain @@ -204,23 +230,27 @@ int atomic_notifier_call_chain(struct atomic_notifier_head *nh, EXPORT_SYMBOL_GPL(atomic_notifier_call_chain); NOKPROBE_SYMBOL(atomic_notifier_call_chain); +/** + * atomic_notifier_call_chain_is_empty - Check whether notifier chain is empty + * @nh: Pointer to head of the atomic notifier chain + * + * Checks whether notifier chain is empty. + * + * Returns true is notifier chain is empty, false otherwise. + */ +bool atomic_notifier_call_chain_is_empty(struct atomic_notifier_head *nh) +{ + return !rcu_access_pointer(nh->head); +} + /* * Blocking notifier chain routines. All access to the chain is * synchronized by an rwsem. */ -/** - * blocking_notifier_chain_register - Add notifier to a blocking notifier chain - * @nh: Pointer to head of the blocking notifier chain - * @n: New entry in notifier chain - * - * Adds a notifier to a blocking notifier chain. - * Must be called in process context. - * - * Returns 0 on success, %-EEXIST on error. - */ -int blocking_notifier_chain_register(struct blocking_notifier_head *nh, - struct notifier_block *n) +static int __blocking_notifier_chain_register(struct blocking_notifier_head *nh, + struct notifier_block *n, + bool unique_priority) { int ret; @@ -230,16 +260,49 @@ int blocking_notifier_chain_register(struct blocking_notifier_head *nh, * such times we must not call down_write(). */ if (unlikely(system_state == SYSTEM_BOOTING)) - return notifier_chain_register(&nh->head, n); + return notifier_chain_register(&nh->head, n, unique_priority); down_write(&nh->rwsem); - ret = notifier_chain_register(&nh->head, n); + ret = notifier_chain_register(&nh->head, n, unique_priority); up_write(&nh->rwsem); return ret; } + +/** + * blocking_notifier_chain_register - Add notifier to a blocking notifier chain + * @nh: Pointer to head of the blocking notifier chain + * @n: New entry in notifier chain + * + * Adds a notifier to a blocking notifier chain. + * Must be called in process context. + * + * Returns 0 on success, %-EEXIST on error. + */ +int blocking_notifier_chain_register(struct blocking_notifier_head *nh, + struct notifier_block *n) +{ + return __blocking_notifier_chain_register(nh, n, false); +} EXPORT_SYMBOL_GPL(blocking_notifier_chain_register); /** + * blocking_notifier_chain_register_unique_prio - Add notifier to a blocking notifier chain + * @nh: Pointer to head of the blocking notifier chain + * @n: New entry in notifier chain + * + * Adds a notifier to an blocking notifier chain if there is no other + * notifier registered using the same priority. + * + * Returns 0 on success, %-EEXIST or %-EBUSY on error. + */ +int blocking_notifier_chain_register_unique_prio(struct blocking_notifier_head *nh, + struct notifier_block *n) +{ + return __blocking_notifier_chain_register(nh, n, true); +} +EXPORT_SYMBOL_GPL(blocking_notifier_chain_register_unique_prio); + +/** * blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain * @nh: Pointer to head of the blocking notifier chain * @n: Entry to remove from notifier chain @@ -341,7 +404,7 @@ EXPORT_SYMBOL_GPL(blocking_notifier_call_chain); int raw_notifier_chain_register(struct raw_notifier_head *nh, struct notifier_block *n) { - return notifier_chain_register(&nh->head, n); + return notifier_chain_register(&nh->head, n, false); } EXPORT_SYMBOL_GPL(raw_notifier_chain_register); @@ -420,10 +483,10 @@ int srcu_notifier_chain_register(struct srcu_notifier_head *nh, * such times we must not call mutex_lock(). */ if (unlikely(system_state == SYSTEM_BOOTING)) - return notifier_chain_register(&nh->head, n); + return notifier_chain_register(&nh->head, n, false); mutex_lock(&nh->mutex); - ret = notifier_chain_register(&nh->head, n); + ret = notifier_chain_register(&nh->head, n, false); mutex_unlock(&nh->mutex); return ret; } diff --git a/kernel/reboot.c b/kernel/reboot.c index 6bcc5d6a6572..bdb635842ec8 100644 --- a/kernel/reboot.c +++ b/kernel/reboot.c @@ -48,12 +48,20 @@ 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; +}; + /* - * If set, this is used for preparing the system to power off. + * Temporary stub that prevents linkage failure while we're in process + * of removing all uses of legacy pm_power_off() around the kernel. */ - -void (*pm_power_off_prepare)(void); -EXPORT_SYMBOL_GPL(pm_power_off_prepare); +void __weak (*pm_power_off)(void); /** * emergency_restart - reboot the system @@ -281,6 +289,332 @@ void kernel_halt(void) } 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; + + return handler->sys_off_cb(&data); +} + +/** + * 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 = kzalloc(sizeof(*handler), GFP_KERNEL); + if (!handler) + return ERR_PTR(-ENOMEM); + + 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: + handler->list = &restart_handler_list; + break; + + default: + kfree(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) { + kfree(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 (!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); + + kfree(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); + + 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; +} + +/* + * Register sys-off handlers for legacy PM callbacks. This allows legacy + * PM callbacks 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. + */ +static int __init legacy_pm_init(void) +{ + register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, SYS_OFF_PRIO_DEFAULT, + legacy_pm_power_off, NULL); + + return 0; +} +core_initcall(legacy_pm_init); + +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) +{ + atomic_notifier_call_chain(&power_off_handler_list, 0, NULL); +} + +/** + * 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); +} +EXPORT_SYMBOL_GPL(kernel_can_power_off); + /** * kernel_power_off - power_off the system * @@ -289,8 +623,7 @@ 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"); @@ -340,7 +673,7 @@ 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()) cmd = LINUX_REBOOT_CMD_HALT; mutex_lock(&system_transition_mutex); |