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@xxxxxxxxxx>
---
drivers/watchdog/softdog.c | 57 ++++++++++++++++++++++++++++++++++++++
1 file changed, 57 insertions(+)
diff --git a/drivers/watchdog/softdog.c b/drivers/watchdog/softdog.c
index 3e4885c1545e..7a1096265f18 100644
--- a/drivers/watchdog/softdog.c
+++ b/drivers/watchdog/softdog.c
@@ -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;
}
--
2.27.0.383.g050319c2ae-goog
