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4cbc69023a
It occurred to me that the panic pretimeout governor will stall the softdog, because it is purely software which simply breaks when the kernel panics. Testing governors with the softdog on the other hand is really useful, so make this feature a compile time option which nees to be enabled explicitly. This also removes the overhead if pretimeout support is not used because it will now be compiled away (saving ~10% on ARM32). Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
162 lines
4.2 KiB
C
162 lines
4.2 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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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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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#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/timer.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 void softdog_fire(unsigned long data)
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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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}
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static struct timer_list softdog_ticktock =
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TIMER_INITIALIZER(softdog_fire, 0, 0);
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static struct watchdog_device softdog_dev;
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static void softdog_pretimeout(unsigned long data)
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{
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watchdog_notify_pretimeout(&softdog_dev);
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}
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static struct timer_list softdog_preticktock =
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TIMER_INITIALIZER(softdog_pretimeout, 0, 0);
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static int softdog_ping(struct watchdog_device *w)
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{
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if (!mod_timer(&softdog_ticktock, jiffies + (w->timeout * HZ)))
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__module_get(THIS_MODULE);
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if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT)) {
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if (w->pretimeout)
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mod_timer(&softdog_preticktock, jiffies +
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(w->timeout - w->pretimeout) * HZ);
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else
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del_timer(&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 (del_timer(&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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del_timer(&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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if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT))
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softdog_info.options |= WDIOF_PRETIMEOUT;
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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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