diff options
| -rw-r--r-- | Documentation/watchdog/watchdog-kernel-api.txt | 13 | ||||
| -rw-r--r-- | drivers/watchdog/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/watchdog/Makefile | 5 | ||||
| -rw-r--r-- | drivers/watchdog/watchdog_dev.c | 23 | ||||
| -rw-r--r-- | drivers/watchdog/watchdog_pretimeout.c | 131 | ||||
| -rw-r--r-- | drivers/watchdog/watchdog_pretimeout.h | 40 | ||||
| -rw-r--r-- | include/linux/watchdog.h | 13 |
7 files changed, 231 insertions, 1 deletions
diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt index 3402dcad5b03..ea277478982f 100644 --- a/Documentation/watchdog/watchdog-kernel-api.txt +++ b/Documentation/watchdog/watchdog-kernel-api.txt @@ -48,6 +48,7 @@ struct watchdog_device { const struct attribute_group **groups; const struct watchdog_info *info; const struct watchdog_ops *ops; + const struct watchdog_governor *gov; unsigned int bootstatus; unsigned int timeout; unsigned int pretimeout; @@ -75,6 +76,7 @@ It contains following fields: * info: a pointer to a watchdog_info structure. This structure gives some additional information about the watchdog timer itself. (Like it's unique name) * ops: a pointer to the list of watchdog operations that the watchdog supports. +* gov: a pointer to the assigned watchdog device pretimeout governor or NULL. * timeout: the watchdog timer's timeout value (in seconds). This is the time after which the system will reboot if user space does not send a heartbeat request if WDOG_ACTIVE is set. @@ -288,3 +290,14 @@ User should follow the following guidelines for setting the priority: * 128: default restart handler, use if no other handler is expected to be available, and/or if restart is sufficient to restart the entire system * 255: highest priority, will preempt all other restart handlers + +To raise a pretimeout notification, the following function should be used: + +void watchdog_notify_pretimeout(struct watchdog_device *wdd) + +The function can be called in the interrupt context. If watchdog pretimeout +governor framework (kbuild CONFIG_WATCHDOG_PRETIMEOUT_GOV symbol) is enabled, +an action is taken by a preconfigured pretimeout governor preassigned to +the watchdog device. If watchdog pretimeout governor framework is not +enabled, watchdog_notify_pretimeout() prints a notification message to +the kernel log buffer. diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 1bffe006ca9a..04d535ae497d 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -1831,4 +1831,11 @@ config USBPCWATCHDOG Most people will say N. +comment "Watchdog Pretimeout Governors" + +config WATCHDOG_PRETIMEOUT_GOV + bool "Enable watchdog pretimeout governors" + help + The option allows to select watchdog pretimeout governors. + endif # WATCHDOG diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index c22ad3ea3539..990c36ed4716 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -3,9 +3,12 @@ # # The WatchDog Timer Driver Core. -watchdog-objs += watchdog_core.o watchdog_dev.o obj-$(CONFIG_WATCHDOG_CORE) += watchdog.o +watchdog-objs += watchdog_core.o watchdog_dev.o + +watchdog-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV) += watchdog_pretimeout.o + # Only one watchdog can succeed. We probe the ISA/PCI/USB based # watchdog-cards first, then the architecture specific watchdog # drivers and then the architecture independent "softdog" driver. diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 4b381a6be2ff..d2d0b5e37a35 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -49,6 +49,7 @@ #include <linux/uaccess.h> /* For copy_to_user/put_user/... */ #include "watchdog_core.h" +#include "watchdog_pretimeout.h" /* * struct watchdog_core_data - watchdog core internal data @@ -488,6 +489,16 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR_RO(state); +static ssize_t pretimeout_governor_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct watchdog_device *wdd = dev_get_drvdata(dev); + + return watchdog_pretimeout_governor_get(wdd, buf); +} +static DEVICE_ATTR_RO(pretimeout_governor); + static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr, int n) { @@ -500,6 +511,10 @@ static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr, else if (attr == &dev_attr_pretimeout.attr && !(wdd->info->options & WDIOF_PRETIMEOUT)) mode = 0; + else if (attr == &dev_attr_pretimeout_governor.attr && + (!(wdd->info->options & WDIOF_PRETIMEOUT) || + !IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV))) + mode = 0; return mode; } @@ -512,6 +527,7 @@ static struct attribute *wdt_attrs[] = { &dev_attr_bootstatus.attr, &dev_attr_status.attr, &dev_attr_nowayout.attr, + &dev_attr_pretimeout_governor.attr, NULL, }; @@ -989,6 +1005,12 @@ int watchdog_dev_register(struct watchdog_device *wdd) return PTR_ERR(dev); } + ret = watchdog_register_pretimeout(wdd); + if (ret) { + device_destroy(&watchdog_class, devno); + watchdog_cdev_unregister(wdd); + } + return ret; } @@ -1002,6 +1024,7 @@ int watchdog_dev_register(struct watchdog_device *wdd) void watchdog_dev_unregister(struct watchdog_device *wdd) { + watchdog_unregister_pretimeout(wdd); device_destroy(&watchdog_class, wdd->wd_data->cdev.dev); watchdog_cdev_unregister(wdd); } diff --git a/drivers/watchdog/watchdog_pretimeout.c b/drivers/watchdog/watchdog_pretimeout.c new file mode 100644 index 000000000000..72612255fb55 --- /dev/null +++ b/drivers/watchdog/watchdog_pretimeout.c @@ -0,0 +1,131 @@ +/* + * Copyright (C) 2015-2016 Mentor Graphics + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + */ + +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/watchdog.h> + +#include "watchdog_pretimeout.h" + +/* Default watchdog pretimeout governor */ +static struct watchdog_governor *default_gov; + +/* The spinlock protects default_gov, wdd->gov and pretimeout_list */ +static DEFINE_SPINLOCK(pretimeout_lock); + +/* List of watchdog devices, which can generate a pretimeout event */ +static LIST_HEAD(pretimeout_list); + +struct watchdog_pretimeout { + struct watchdog_device *wdd; + struct list_head entry; +}; + +int watchdog_pretimeout_governor_get(struct watchdog_device *wdd, char *buf) +{ + int count = 0; + + spin_lock_irq(&pretimeout_lock); + if (wdd->gov) + count = sprintf(buf, "%s\n", wdd->gov->name); + spin_unlock_irq(&pretimeout_lock); + + return count; +} + +void watchdog_notify_pretimeout(struct watchdog_device *wdd) +{ + unsigned long flags; + + spin_lock_irqsave(&pretimeout_lock, flags); + if (!wdd->gov) { + spin_unlock_irqrestore(&pretimeout_lock, flags); + return; + } + + wdd->gov->pretimeout(wdd); + spin_unlock_irqrestore(&pretimeout_lock, flags); +} +EXPORT_SYMBOL_GPL(watchdog_notify_pretimeout); + +int watchdog_register_governor(struct watchdog_governor *gov) +{ + struct watchdog_pretimeout *p; + + if (!default_gov) { + spin_lock_irq(&pretimeout_lock); + default_gov = gov; + + list_for_each_entry(p, &pretimeout_list, entry) + if (!p->wdd->gov) + p->wdd->gov = default_gov; + spin_unlock_irq(&pretimeout_lock); + } + + return 0; +} +EXPORT_SYMBOL(watchdog_register_governor); + +void watchdog_unregister_governor(struct watchdog_governor *gov) +{ + struct watchdog_pretimeout *p; + + spin_lock_irq(&pretimeout_lock); + if (gov == default_gov) + default_gov = NULL; + + list_for_each_entry(p, &pretimeout_list, entry) + if (p->wdd->gov == gov) + p->wdd->gov = default_gov; + spin_unlock_irq(&pretimeout_lock); +} +EXPORT_SYMBOL(watchdog_unregister_governor); + +int watchdog_register_pretimeout(struct watchdog_device *wdd) +{ + struct watchdog_pretimeout *p; + + if (!(wdd->info->options & WDIOF_PRETIMEOUT)) + return 0; + + p = kzalloc(sizeof(*p), GFP_KERNEL); + if (!p) + return -ENOMEM; + + spin_lock_irq(&pretimeout_lock); + list_add(&p->entry, &pretimeout_list); + p->wdd = wdd; + wdd->gov = default_gov; + spin_unlock_irq(&pretimeout_lock); + + return 0; +} + +void watchdog_unregister_pretimeout(struct watchdog_device *wdd) +{ + struct watchdog_pretimeout *p, *t; + + if (!(wdd->info->options & WDIOF_PRETIMEOUT)) + return; + + spin_lock_irq(&pretimeout_lock); + wdd->gov = NULL; + + list_for_each_entry_safe(p, t, &pretimeout_list, entry) { + if (p->wdd == wdd) { + list_del(&p->entry); + break; + } + } + spin_unlock_irq(&pretimeout_lock); + + kfree(p); +} diff --git a/drivers/watchdog/watchdog_pretimeout.h b/drivers/watchdog/watchdog_pretimeout.h new file mode 100644 index 000000000000..c6cd9f80adb2 --- /dev/null +++ b/drivers/watchdog/watchdog_pretimeout.h @@ -0,0 +1,40 @@ +#ifndef __WATCHDOG_PRETIMEOUT_H +#define __WATCHDOG_PRETIMEOUT_H + +#define WATCHDOG_GOV_NAME_MAXLEN 20 + +struct watchdog_device; + +struct watchdog_governor { + const char name[WATCHDOG_GOV_NAME_MAXLEN]; + void (*pretimeout)(struct watchdog_device *wdd); +}; + +#if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV) +/* Interfaces to watchdog pretimeout governors */ +int watchdog_register_governor(struct watchdog_governor *gov); +void watchdog_unregister_governor(struct watchdog_governor *gov); + +/* Interfaces to watchdog_dev.c */ +int watchdog_register_pretimeout(struct watchdog_device *wdd); +void watchdog_unregister_pretimeout(struct watchdog_device *wdd); +int watchdog_pretimeout_governor_get(struct watchdog_device *wdd, char *buf); + +#else +static inline int watchdog_register_pretimeout(struct watchdog_device *wdd) +{ + return 0; +} + +static inline void watchdog_unregister_pretimeout(struct watchdog_device *wdd) +{ +} + +static inline int watchdog_pretimeout_governor_get(struct watchdog_device *wdd, + char *buf) +{ + return -EINVAL; +} +#endif + +#endif diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index 4035df7ec023..35a4d8185b51 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -19,6 +19,7 @@ struct watchdog_ops; struct watchdog_device; struct watchdog_core_data; +struct watchdog_governor; /** struct watchdog_ops - The watchdog-devices operations * @@ -61,6 +62,7 @@ struct watchdog_ops { * watchdog device. * @info: Pointer to a watchdog_info structure. * @ops: Pointer to the list of watchdog operations. + * @gov: Pointer to watchdog pretimeout governor. * @bootstatus: Status of the watchdog device at boot. * @timeout: The watchdog devices timeout value (in seconds). * @pretimeout: The watchdog devices pre_timeout value. @@ -97,6 +99,7 @@ struct watchdog_device { const struct attribute_group **groups; const struct watchdog_info *info; const struct watchdog_ops *ops; + const struct watchdog_governor *gov; unsigned int bootstatus; unsigned int timeout; unsigned int pretimeout; @@ -185,6 +188,16 @@ static inline void *watchdog_get_drvdata(struct watchdog_device *wdd) return wdd->driver_data; } +/* Use the following functions to report watchdog pretimeout event */ +#if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV) +void watchdog_notify_pretimeout(struct watchdog_device *wdd); +#else +static inline void watchdog_notify_pretimeout(struct watchdog_device *wdd) +{ + pr_alert("watchdog%d: pretimeout event\n", wdd->id); +} +#endif + /* drivers/watchdog/watchdog_core.c */ void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority); extern int watchdog_init_timeout(struct watchdog_device *wdd, |