change system file

hc

2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771

 kernel/drivers/watchdog/softdog.c
..
..
@@ -1,13 +1,9 @@
1
+// SPDX-License-Identifier: GPL-2.0+
1
2
 /*
2
3
  *	SoftDog:	A Software Watchdog Device
3
4
  *
4
5
  *	(c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
5
6
  *							All Rights Reserved.
6
- *
7
- *	This program is free software; you can redistribute it and/or
8
- *	modify it under the terms of the GNU General Public License
9
- *	as published by the Free Software Foundation; either version
10
- *	2 of the License, or (at your option) any later version.
11
7
  *
12
8
  *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
13
9
  *	warranty for any of this software. This material is provided
..
..
@@ -24,11 +20,13 @@
24
20
 #include <linux/hrtimer.h>
25
21
 #include <linux/init.h>
26
22
 #include <linux/kernel.h>
23
+#include <linux/kthread.h>
27
24
 #include <linux/module.h>
28
25
 #include <linux/moduleparam.h>
29
26
 #include <linux/reboot.h>
30
27
 #include <linux/types.h>
31
28
 #include <linux/watchdog.h>
29
+#include <linux/workqueue.h>
32
30
 
33
31
 #define TIMER_MARGIN	60		/* Default is 60 seconds */
34
32
 static unsigned int soft_margin = TIMER_MARGIN;	/* in seconds */
..
..
@@ -53,11 +51,34 @@
53
51
 MODULE_PARM_DESC(soft_panic,
54
52
 	"Softdog action, set to 1 to panic, 0 to reboot (default=0)");
55
53
 
54
+static char *soft_reboot_cmd;
55
+module_param(soft_reboot_cmd, charp, 0000);
56
+MODULE_PARM_DESC(soft_reboot_cmd,
57
+	"Set reboot command. Emergency reboot takes place if unset");
58
+
59
+static bool soft_active_on_boot;
60
+module_param(soft_active_on_boot, bool, 0000);
61
+MODULE_PARM_DESC(soft_active_on_boot,
62
+	"Set to true to active Softdog on boot (default=false)");
63
+
56
64
 static struct hrtimer softdog_ticktock;
57
65
 static struct hrtimer softdog_preticktock;
58
66
 
67
+static int reboot_kthread_fn(void *data)
68
+{
69
+	kernel_restart(soft_reboot_cmd);
70
+	return -EPERM; /* Should not reach here */
71
+}
72
+
73
+static void reboot_work_fn(struct work_struct *unused)
74
+{
75
+	kthread_run(reboot_kthread_fn, NULL, "softdog_reboot");
76
+}
77
+
59
78
 static enum hrtimer_restart softdog_fire(struct hrtimer *timer)
60
79
 {
80
+	static bool soft_reboot_fired;
81
+
61
82
 	module_put(THIS_MODULE);
62
83
 	if (soft_noboot) {
63
84
 		pr_crit("Triggered - Reboot ignored\n");
..
..
@@ -66,6 +87,33 @@
66
87
 		panic("Software Watchdog Timer expired");
67
88
 	} else {
68
89
 		pr_crit("Initiating system reboot\n");
90
+		if (!soft_reboot_fired && soft_reboot_cmd != NULL) {
91
+			static DECLARE_WORK(reboot_work, reboot_work_fn);
92
+			/*
93
+			 * The 'kernel_restart' is a 'might-sleep' operation.
94
+			 * Also, executing it in system-wide workqueues blocks
95
+			 * any driver from using the same workqueue in its
96
+			 * shutdown callback function. Thus, we should execute
97
+			 * the 'kernel_restart' in a standalone kernel thread.
98
+			 * But since starting a kernel thread is also a
99
+			 * 'might-sleep' operation, so the 'reboot_work' is
100
+			 * required as a launcher of the kernel thread.
101
+			 *
102
+			 * After request the reboot, restart the timer to
103
+			 * schedule an 'emergency_restart' reboot after
104
+			 * 'TIMER_MARGIN' seconds. It's because if the softdog
105
+			 * hangs, it might be because of scheduling issues. And
106
+			 * if that is the case, both 'schedule_work' and
107
+			 * 'kernel_restart' may possibly be malfunctional at the
108
+			 * same time.
109
+			 */
110
+			soft_reboot_fired = true;
111
+			schedule_work(&reboot_work);
112
+			hrtimer_add_expires_ns(timer,
113
+					(u64)TIMER_MARGIN * NSEC_PER_SEC);
114
+
115
+			return HRTIMER_RESTART;
116
+		}
69
117
 		emergency_restart();
70
118
 		pr_crit("Reboot didn't ?????\n");
71
119
 	}
..
..
@@ -149,12 +197,17 @@
149
197
 		softdog_preticktock.function = softdog_pretimeout;
150
198
 	}
151
199
 
200
+	if (soft_active_on_boot)
201
+		softdog_ping(&softdog_dev);
202
+
152
203
 	ret = watchdog_register_device(&softdog_dev);
153
204
 	if (ret)
154
205
 		return ret;
155
206
 
156
207
 	pr_info("initialized. soft_noboot=%d soft_margin=%d sec soft_panic=%d (nowayout=%d)\n",
157
208
 		soft_noboot, softdog_dev.timeout, soft_panic, nowayout);
209
+	pr_info("             soft_reboot_cmd=%s soft_active_on_boot=%d\n",
210
+		soft_reboot_cmd ?: "<not set>", soft_active_on_boot);
158
211
 
159
212
 	return 0;
160
213
 }