172 lines
4.5 KiB
C
172 lines
4.5 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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/hrtimer.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/reboot.h>
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#include <linux/types.h>
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#include <linux/watchdog.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;
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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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static struct hrtimer softdog_ticktock;
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static struct hrtimer softdog_preticktock;
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static enum hrtimer_restart softdog_fire(struct hrtimer *timer)
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{
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module_put(THIS_MODULE);
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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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return HRTIMER_NORESTART;
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}
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static struct watchdog_device softdog_dev;
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static enum hrtimer_restart softdog_pretimeout(struct hrtimer *timer)
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{
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watchdog_notify_pretimeout(&softdog_dev);
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return HRTIMER_NORESTART;
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}
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static int softdog_ping(struct watchdog_device *w)
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{
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if (!hrtimer_active(&softdog_ticktock))
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__module_get(THIS_MODULE);
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hrtimer_start(&softdog_ticktock, ktime_set(w->timeout, 0),
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HRTIMER_MODE_REL);
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if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT)) {
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if (w->pretimeout)
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hrtimer_start(&softdog_preticktock,
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ktime_set(w->timeout - w->pretimeout, 0),
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HRTIMER_MODE_REL);
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else
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hrtimer_cancel(&softdog_preticktock);
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}
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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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if (hrtimer_cancel(&softdog_ticktock))
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module_put(THIS_MODULE);
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if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT))
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hrtimer_cancel(&softdog_preticktock);
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return 0;
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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 const 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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};
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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 = 65535,
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.timeout = TIMER_MARGIN,
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};
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static int __init softdog_init(void)
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{
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int ret;
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watchdog_init_timeout(&softdog_dev, soft_margin, NULL);
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watchdog_set_nowayout(&softdog_dev, nowayout);
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watchdog_stop_on_reboot(&softdog_dev);
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hrtimer_init(&softdog_ticktock, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
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softdog_ticktock.function = softdog_fire;
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if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT)) {
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softdog_info.options |= WDIOF_PRETIMEOUT;
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hrtimer_init(&softdog_preticktock, CLOCK_MONOTONIC,
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HRTIMER_MODE_REL);
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softdog_preticktock.function = softdog_pretimeout;
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}
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ret = watchdog_register_device(&softdog_dev);
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if (ret)
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return ret;
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pr_info("initialized. soft_noboot=%d soft_margin=%d sec soft_panic=%d (nowayout=%d)\n",
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soft_noboot, softdog_dev.timeout, soft_panic, nowayout);
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return 0;
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}
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module_init(softdog_init);
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static void __exit softdog_exit(void)
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{
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watchdog_unregister_device(&softdog_dev);
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}
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module_exit(softdog_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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