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