1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Watchdog driver for z/VM and LPAR using the diag 288 interface.
*
* Under z/VM, expiration of the watchdog will send a "system restart" command
* to CP.
*
* The command can be altered using the module parameter "cmd". This is
* not recommended because it's only supported on z/VM but not whith LPAR.
*
* On LPAR, the watchdog will always trigger a system restart. the module
* paramter cmd is meaningless here.
*
*
* Copyright IBM Corp. 2004, 2013
* Author(s): Arnd Bergmann (arndb@de.ibm.com)
* Philipp Hachtmann (phacht@de.ibm.com)
*
*/
#define KMSG_COMPONENT "diag288_wdt"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/watchdog.h>
#include <asm/ebcdic.h>
#include <asm/diag.h>
#include <linux/io.h>
#define MAX_CMDLEN 240
#define DEFAULT_CMD "SYSTEM RESTART"
#define MIN_INTERVAL 15 /* Minimal time supported by diag88 */
#define MAX_INTERVAL 3600 /* One hour should be enough - pure estimation */
#define WDT_DEFAULT_TIMEOUT 30
/* Function codes - init, change, cancel */
#define WDT_FUNC_INIT 0
#define WDT_FUNC_CHANGE 1
#define WDT_FUNC_CANCEL 2
#define WDT_FUNC_CONCEAL 0x80000000
/* Action codes for LPAR watchdog */
#define LPARWDT_RESTART 0
static char wdt_cmd[MAX_CMDLEN] = DEFAULT_CMD;
static bool conceal_on;
static bool nowayout_info = WATCHDOG_NOWAYOUT;
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
MODULE_AUTHOR("Philipp Hachtmann <phacht@de.ibm.com>");
MODULE_DESCRIPTION("System z diag288 Watchdog Timer");
module_param_string(cmd, wdt_cmd, MAX_CMDLEN, 0644);
MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers (z/VM only)");
module_param_named(conceal, conceal_on, bool, 0644);
MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog is active (z/VM only)");
module_param_named(nowayout, nowayout_info, bool, 0444);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = CONFIG_WATCHDOG_NOWAYOUT)");
MODULE_ALIAS("vmwatchdog");
static char *cmd_buf;
static int diag288(unsigned int func, unsigned int timeout,
unsigned long action, unsigned int len)
{
union register_pair r1 = { .even = func, .odd = timeout, };
union register_pair r3 = { .even = action, .odd = len, };
int err;
diag_stat_inc(DIAG_STAT_X288);
err = -EINVAL;
asm volatile(
" diag %[r1],%[r3],0x288\n"
"0: la %[err],0\n"
"1:\n"
EX_TABLE(0b, 1b)
: [err] "+d" (err)
: [r1] "d" (r1.pair), [r3] "d" (r3.pair)
: "cc", "memory");
return err;
}
static int diag288_str(unsigned int func, unsigned int timeout, char *cmd)
{
ssize_t len;
len = strscpy(cmd_buf, cmd, MAX_CMDLEN);
if (len < 0)
return len;
ASCEBC(cmd_buf, MAX_CMDLEN);
EBC_TOUPPER(cmd_buf, MAX_CMDLEN);
return diag288(func, timeout, virt_to_phys(cmd_buf), len);
}
static int wdt_start(struct watchdog_device *dev)
{
int ret;
unsigned int func;
if (MACHINE_IS_VM) {
func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
: WDT_FUNC_INIT;
ret = diag288_str(func, dev->timeout, wdt_cmd);
WARN_ON(ret != 0);
} else {
ret = diag288(WDT_FUNC_INIT, dev->timeout, LPARWDT_RESTART, 0);
}
if (ret) {
pr_err("The watchdog cannot be activated\n");
return ret;
}
return 0;
}
static int wdt_stop(struct watchdog_device *dev)
{
return diag288(WDT_FUNC_CANCEL, 0, 0, 0);
}
static int wdt_ping(struct watchdog_device *dev)
{
int ret;
unsigned int func;
if (MACHINE_IS_VM) {
/*
* It seems to be ok to z/VM to use the init function to
* retrigger the watchdog. On LPAR WDT_FUNC_CHANGE must
* be used when the watchdog is running.
*/
func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
: WDT_FUNC_INIT;
ret = diag288_str(func, dev->timeout, wdt_cmd);
WARN_ON(ret != 0);
} else {
ret = diag288(WDT_FUNC_CHANGE, dev->timeout, 0, 0);
}
if (ret)
pr_err("The watchdog timer cannot be started or reset\n");
return ret;
}
static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to)
{
dev->timeout = new_to;
return wdt_ping(dev);
}
static const struct watchdog_ops wdt_ops = {
.owner = THIS_MODULE,
.start = wdt_start,
.stop = wdt_stop,
.ping = wdt_ping,
.set_timeout = wdt_set_timeout,
};
static const struct watchdog_info wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.firmware_version = 0,
.identity = "z Watchdog",
};
static struct watchdog_device wdt_dev = {
.parent = NULL,
.info = &wdt_info,
.ops = &wdt_ops,
.bootstatus = 0,
.timeout = WDT_DEFAULT_TIMEOUT,
.min_timeout = MIN_INTERVAL,
.max_timeout = MAX_INTERVAL,
};
static int __init diag288_init(void)
{
int ret;
watchdog_set_nowayout(&wdt_dev, nowayout_info);
if (MACHINE_IS_VM) {
cmd_buf = kmalloc(MAX_CMDLEN, GFP_KERNEL);
if (!cmd_buf) {
pr_err("The watchdog cannot be initialized\n");
return -ENOMEM;
}
ret = diag288_str(WDT_FUNC_INIT, MIN_INTERVAL, "BEGIN");
if (ret != 0) {
pr_err("The watchdog cannot be initialized\n");
kfree(cmd_buf);
return -EINVAL;
}
} else {
if (diag288(WDT_FUNC_INIT, WDT_DEFAULT_TIMEOUT,
LPARWDT_RESTART, 0)) {
pr_err("The watchdog cannot be initialized\n");
return -EINVAL;
}
}
if (diag288(WDT_FUNC_CANCEL, 0, 0, 0)) {
pr_err("The watchdog cannot be deactivated\n");
return -EINVAL;
}
return watchdog_register_device(&wdt_dev);
}
static void __exit diag288_exit(void)
{
watchdog_unregister_device(&wdt_dev);
kfree(cmd_buf);
}
module_init(diag288_init);
module_exit(diag288_exit);
|
