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watchdog: softdog: Add options 'soft_reboot_cmd' and 'soft_active_on_boot'

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Add module parameters 'soft_reboot_cmd' and 'soft_active_on_boot' for
customizing softdog configuration; config reboot command by assigning
soft_reboot_cmd, and set soft_active_on_boot to start up softdog
timer at module initialization stage.

Signed-off-by: Woody Lin <woodylin@google.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200708083218.3157213-1-woodylin@google.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
This commit is contained in:
Woody Lin 2020-07-08 16:32:19 +08:00 committed by Wim Van Sebroeck
parent f1889c9066
commit 36a8947c6b
1 changed files with 57 additions and 0 deletions
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57
drivers/watchdog/softdog.c
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@ -20,11 +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 */
@ -49,11 +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");
@ -62,6 +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");
}
@ -145,12 +197,17 @@ static int __init softdog_init(void)
softdog_preticktock.function = softdog_pretimeout;
}
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;
}