diff options
Diffstat (limited to 'drivers/watchdog/softdog.c')
| -rw-r--r-- | drivers/watchdog/softdog.c | 71 |
1 files changed, 61 insertions, 10 deletions
diff --git a/drivers/watchdog/softdog.c b/drivers/watchdog/softdog.c index 060740625485..0820e35ad2e3 100644 --- a/drivers/watchdog/softdog.c +++ b/drivers/watchdog/softdog.c @@ -1,14 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0+ /* * 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. @@ -24,11 +20,13 @@ #include <linux/hrtimer.h> #include <linux/init.h> #include <linux/kernel.h> +#include <linux/kthread.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/reboot.h> #include <linux/types.h> #include <linux/watchdog.h> +#include <linux/workqueue.h> #define TIMER_MARGIN 60 /* Default is 60 seconds */ static unsigned int soft_margin = TIMER_MARGIN; /* in seconds */ @@ -53,11 +51,34 @@ module_param(soft_panic, int, 0); MODULE_PARM_DESC(soft_panic, "Softdog action, set to 1 to panic, 0 to reboot (default=0)"); +static char *soft_reboot_cmd; +module_param(soft_reboot_cmd, charp, 0000); +MODULE_PARM_DESC(soft_reboot_cmd, + "Set reboot command. Emergency reboot takes place if unset"); + +static bool soft_active_on_boot; +module_param(soft_active_on_boot, bool, 0000); +MODULE_PARM_DESC(soft_active_on_boot, + "Set to true to active Softdog on boot (default=false)"); + static struct hrtimer softdog_ticktock; static struct hrtimer softdog_preticktock; +static int reboot_kthread_fn(void *data) +{ + kernel_restart(soft_reboot_cmd); + return -EPERM; /* Should not reach here */ +} + +static void reboot_work_fn(struct work_struct *unused) +{ + kthread_run(reboot_kthread_fn, NULL, "softdog_reboot"); +} + static enum hrtimer_restart softdog_fire(struct hrtimer *timer) { + static bool soft_reboot_fired; + module_put(THIS_MODULE); if (soft_noboot) { pr_crit("Triggered - Reboot ignored\n"); @@ -66,6 +87,33 @@ static enum hrtimer_restart softdog_fire(struct hrtimer *timer) panic("Software Watchdog Timer expired"); } else { pr_crit("Initiating system reboot\n"); + if (!soft_reboot_fired && soft_reboot_cmd != NULL) { + static DECLARE_WORK(reboot_work, reboot_work_fn); + /* + * The 'kernel_restart' is a 'might-sleep' operation. + * Also, executing it in system-wide workqueues blocks + * any driver from using the same workqueue in its + * shutdown callback function. Thus, we should execute + * the 'kernel_restart' in a standalone kernel thread. + * But since starting a kernel thread is also a + * 'might-sleep' operation, so the 'reboot_work' is + * required as a launcher of the kernel thread. + * + * After request the reboot, restart the timer to + * schedule an 'emergency_restart' reboot after + * 'TIMER_MARGIN' seconds. It's because if the softdog + * hangs, it might be because of scheduling issues. And + * if that is the case, both 'schedule_work' and + * 'kernel_restart' may possibly be malfunctional at the + * same time. + */ + soft_reboot_fired = true; + schedule_work(&reboot_work); + hrtimer_add_expires_ns(timer, + (u64)TIMER_MARGIN * NSEC_PER_SEC); + + return HRTIMER_RESTART; + } emergency_restart(); pr_crit("Reboot didn't ?????\n"); } @@ -139,22 +187,25 @@ static int __init softdog_init(void) watchdog_set_nowayout(&softdog_dev, nowayout); watchdog_stop_on_reboot(&softdog_dev); - hrtimer_init(&softdog_ticktock, CLOCK_MONOTONIC, HRTIMER_MODE_REL); - softdog_ticktock.function = softdog_fire; + hrtimer_setup(&softdog_ticktock, softdog_fire, CLOCK_MONOTONIC, HRTIMER_MODE_REL); if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT)) { softdog_info.options |= WDIOF_PRETIMEOUT; - hrtimer_init(&softdog_preticktock, CLOCK_MONOTONIC, - HRTIMER_MODE_REL); - softdog_preticktock.function = softdog_pretimeout; + hrtimer_setup(&softdog_preticktock, softdog_pretimeout, CLOCK_MONOTONIC, + HRTIMER_MODE_REL); } + if (soft_active_on_boot) + softdog_ping(&softdog_dev); + ret = watchdog_register_device(&softdog_dev); if (ret) return ret; pr_info("initialized. soft_noboot=%d soft_margin=%d sec soft_panic=%d (nowayout=%d)\n", soft_noboot, softdog_dev.timeout, soft_panic, nowayout); + pr_info(" soft_reboot_cmd=%s soft_active_on_boot=%d\n", + soft_reboot_cmd ?: "<not set>", soft_active_on_boot); return 0; } |