--- /dev/null
+/*
+ * 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");
Code Review / kvmfornfv.git / blobdiff