diff options
Diffstat (limited to 'drivers/watchdog/softdog.c')
| -rw-r--r-- | drivers/watchdog/softdog.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/drivers/watchdog/softdog.c b/drivers/watchdog/softdog.c new file mode 100644 index 00000000..fe83beb8 --- /dev/null +++ b/drivers/watchdog/softdog.c @@ -0,0 +1,211 @@ +/* + * SoftDog: A Software Watchdog Device + * + * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>, + * All Rights Reserved. + * + * 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. + * + * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide + * warranty for any of this software. This material is provided + * "AS-IS" and at no charge. + * + * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> + * + * Software only watchdog driver. Unlike its big brother the WDT501P + * driver this won't always recover a failed machine. + * + * 03/96: Angelo Haritsis <ah@doc.ic.ac.uk> : + * Modularised. + * Added soft_margin; use upon insmod to change the timer delay. + * NB: uses same minor as wdt (WATCHDOG_MINOR); we could use separate + * minors. + * + * 19980911 Alan Cox + * Made SMP safe for 2.3.x + * + * 20011127 Joel Becker (jlbec@evilplan.org> + * Added soft_noboot; Allows testing the softdog trigger without + * requiring a recompile. + * Added WDIOC_GETTIMEOUT and WDIOC_SETTIMOUT. + * + * 20020530 Joel Becker <joel.becker@oracle.com> + * Added Matt Domsch's nowayout module option. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.h> +#include <linux/timer.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/notifier.h> +#include <linux/reboot.h> +#include <linux/init.h> +#include <linux/jiffies.h> +#include <linux/kernel.h> + +#define TIMER_MARGIN 60 /* Default is 60 seconds */ +static unsigned int soft_margin = TIMER_MARGIN; /* in seconds */ +module_param(soft_margin, uint, 0); +MODULE_PARM_DESC(soft_margin, + "Watchdog soft_margin in seconds. (0 < soft_margin < 65536, default=" + __MODULE_STRING(TIMER_MARGIN) ")"); + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, + "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +static int soft_noboot = 0; +module_param(soft_noboot, int, 0); +MODULE_PARM_DESC(soft_noboot, + "Softdog action, set to 1 to ignore reboots, 0 to reboot (default=0)"); + +static int soft_panic; +module_param(soft_panic, int, 0); +MODULE_PARM_DESC(soft_panic, + "Softdog action, set to 1 to panic, 0 to reboot (default=0)"); + +/* + * Our timer + */ + +static void watchdog_fire(unsigned long); + +static struct timer_list watchdog_ticktock = + TIMER_INITIALIZER(watchdog_fire, 0, 0); + +/* + * If the timer expires.. + */ + +static void watchdog_fire(unsigned long data) +{ + if (soft_noboot) + pr_crit("Triggered - Reboot ignored\n"); + else if (soft_panic) { + pr_crit("Initiating panic\n"); + panic("Software Watchdog Timer expired"); + } else { + pr_crit("Initiating system reboot\n"); + emergency_restart(); + pr_crit("Reboot didn't ?????\n"); + } +} + +/* + * Softdog operations + */ + +static int softdog_ping(struct watchdog_device *w) +{ + mod_timer(&watchdog_ticktock, jiffies+(w->timeout*HZ)); + return 0; +} + +static int softdog_stop(struct watchdog_device *w) +{ + del_timer(&watchdog_ticktock); + return 0; +} + +static int softdog_set_timeout(struct watchdog_device *w, unsigned int t) +{ + w->timeout = t; + return 0; +} + +/* + * Notifier for system down + */ + +static int softdog_notify_sys(struct notifier_block *this, unsigned long code, + void *unused) +{ + if (code == SYS_DOWN || code == SYS_HALT) + /* Turn the WDT off */ + softdog_stop(NULL); + return NOTIFY_DONE; +} + +/* + * Kernel Interfaces + */ + +static struct notifier_block softdog_notifier = { + .notifier_call = softdog_notify_sys, +}; + +static struct watchdog_info softdog_info = { + .identity = "Software Watchdog", + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, +}; + +static struct watchdog_ops softdog_ops = { + .owner = THIS_MODULE, + .start = softdog_ping, + .stop = softdog_stop, + .ping = softdog_ping, + .set_timeout = softdog_set_timeout, +}; + +static struct watchdog_device softdog_dev = { + .info = &softdog_info, + .ops = &softdog_ops, + .min_timeout = 1, + .max_timeout = 0xFFFF +}; + +static int __init watchdog_init(void) +{ + int ret; + + /* Check that the soft_margin value is within it's range; + if not reset to the default */ + if (soft_margin < 1 || soft_margin > 65535) { + pr_info("soft_margin must be 0 < soft_margin < 65536, using %d\n", + TIMER_MARGIN); + return -EINVAL; + } + softdog_dev.timeout = soft_margin; + + watchdog_set_nowayout(&softdog_dev, nowayout); + + ret = register_reboot_notifier(&softdog_notifier); + if (ret) { + pr_err("cannot register reboot notifier (err=%d)\n", ret); + return ret; + } + + ret = watchdog_register_device(&softdog_dev); + if (ret) { + unregister_reboot_notifier(&softdog_notifier); + return ret; + } + + pr_info("Software Watchdog Timer: 0.08 initialized. soft_noboot=%d soft_margin=%d sec soft_panic=%d (nowayout=%d)\n", + soft_noboot, soft_margin, soft_panic, nowayout); + + return 0; +} + +static void __exit watchdog_exit(void) +{ + watchdog_unregister_device(&softdog_dev); + unregister_reboot_notifier(&softdog_notifier); +} + +module_init(watchdog_init); +module_exit(watchdog_exit); + +MODULE_AUTHOR("Alan Cox"); +MODULE_DESCRIPTION("Software Watchdog Device Driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |