/* * 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/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; 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, .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");