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
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
|
/*
* Watchdog implementation based on z/VM Watchdog Timer API
*
* The user space watchdog daemon can use this driver as
* /dev/vmwatchdog to have z/VM execute the specified CP
* command when the timeout expires. The default command is
* "IPL", which which cause an immediate reboot.
*/
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/watchdog.h>
#include <asm/ebcdic.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#define MAX_CMDLEN 240
#define MIN_INTERVAL 15
static char vmwdt_cmd[MAX_CMDLEN] = "IPL";
static int vmwdt_conceal;
static int vmwdt_nowayout = WATCHDOG_NOWAYOUT;
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
MODULE_DESCRIPTION("z/VM Watchdog Timer");
module_param_string(cmd, vmwdt_cmd, MAX_CMDLEN, 0644);
MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers");
module_param_named(conceal, vmwdt_conceal, bool, 0644);
MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog "
" is active");
module_param_named(nowayout, vmwdt_nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
" (default=CONFIG_WATCHDOG_NOWAYOUT)");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
static unsigned int vmwdt_interval = 60;
static unsigned long vmwdt_is_open;
static int vmwdt_expect_close;
enum vmwdt_func {
/* function codes */
wdt_init = 0,
wdt_change = 1,
wdt_cancel = 2,
/* flags */
wdt_conceal = 0x80000000,
};
static int __diag288(enum vmwdt_func func, unsigned int timeout,
char *cmd, size_t len)
{
register unsigned long __func asm("2") = func;
register unsigned long __timeout asm("3") = timeout;
register unsigned long __cmdp asm("4") = virt_to_phys(cmd);
register unsigned long __cmdl asm("5") = len;
int err;
err = -EINVAL;
asm volatile(
" diag %1,%3,0x288\n"
"0: la %0,0\n"
"1:\n"
EX_TABLE(0b,1b)
: "+d" (err) : "d"(__func), "d"(__timeout),
"d"(__cmdp), "d"(__cmdl) : "1", "cc");
return err;
}
static int vmwdt_keepalive(void)
{
/* we allocate new memory every time to avoid having
* to track the state. static allocation is not an
* option since that might not be contiguous in real
* storage in case of a modular build */
static char *ebc_cmd;
size_t len;
int ret;
unsigned int func;
ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
if (!ebc_cmd)
return -ENOMEM;
len = strlcpy(ebc_cmd, vmwdt_cmd, MAX_CMDLEN);
ASCEBC(ebc_cmd, MAX_CMDLEN);
EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
func = vmwdt_conceal ? (wdt_init | wdt_conceal) : wdt_init;
ret = __diag288(func, vmwdt_interval, ebc_cmd, len);
WARN_ON(ret != 0);
kfree(ebc_cmd);
return ret;
}
static int vmwdt_disable(void)
{
int ret = __diag288(wdt_cancel, 0, "", 0);
WARN_ON(ret != 0);
return ret;
}
static int __init vmwdt_probe(void)
{
/* there is no real way to see if the watchdog is supported,
* so we try initializing it with a NOP command ("BEGIN")
* that won't cause any harm even if the following disable
* fails for some reason */
static char __initdata ebc_begin[] = {
194, 197, 199, 201, 213
};
if (__diag288(wdt_init, 15, ebc_begin, sizeof(ebc_begin)) != 0)
return -EINVAL;
return vmwdt_disable();
}
static int vmwdt_open(struct inode *i, struct file *f)
{
int ret;
if (test_and_set_bit(0, &vmwdt_is_open))
return -EBUSY;
ret = vmwdt_keepalive();
if (ret)
clear_bit(0, &vmwdt_is_open);
return ret ? ret : nonseekable_open(i, f);
}
static int vmwdt_close(struct inode *i, struct file *f)
{
if (vmwdt_expect_close == 42)
vmwdt_disable();
vmwdt_expect_close = 0;
clear_bit(0, &vmwdt_is_open);
return 0;
}
static struct watchdog_info vmwdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.firmware_version = 0,
.identity = "z/VM Watchdog Timer",
};
static int vmwdt_ioctl(struct inode *i, struct file *f,
unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user((void __user *)arg, &vmwdt_info,
sizeof(vmwdt_info)))
return -EFAULT;
return 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, (int __user *)arg);
case WDIOC_GETTEMP:
return -EINVAL;
case WDIOC_SETOPTIONS:
{
int options, ret;
if (get_user(options, (int __user *)arg))
return -EFAULT;
ret = -EINVAL;
if (options & WDIOS_DISABLECARD) {
ret = vmwdt_disable();
if (ret)
return ret;
}
if (options & WDIOS_ENABLECARD) {
ret = vmwdt_keepalive();
}
return ret;
}
case WDIOC_GETTIMEOUT:
return put_user(vmwdt_interval, (int __user *)arg);
case WDIOC_SETTIMEOUT:
{
int interval;
if (get_user(interval, (int __user *)arg))
return -EFAULT;
if (interval < MIN_INTERVAL)
return -EINVAL;
vmwdt_interval = interval;
}
return vmwdt_keepalive();
case WDIOC_KEEPALIVE:
return vmwdt_keepalive();
}
return -EINVAL;
}
static ssize_t vmwdt_write(struct file *f, const char __user *buf,
size_t count, loff_t *ppos)
{
if(count) {
if (!vmwdt_nowayout) {
size_t i;
/* note: just in case someone wrote the magic character
* five months ago... */
vmwdt_expect_close = 0;
for (i = 0; i != count; i++) {
char c;
if (get_user(c, buf+i))
return -EFAULT;
if (c == 'V')
vmwdt_expect_close = 42;
}
}
/* someone wrote to us, we should restart timer */
vmwdt_keepalive();
}
return count;
}
static const struct file_operations vmwdt_fops = {
.open = &vmwdt_open,
.release = &vmwdt_close,
.ioctl = &vmwdt_ioctl,
.write = &vmwdt_write,
.owner = THIS_MODULE,
};
static struct miscdevice vmwdt_dev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &vmwdt_fops,
};
static int __init vmwdt_init(void)
{
int ret;
ret = vmwdt_probe();
if (ret)
return ret;
return misc_register(&vmwdt_dev);
}
module_init(vmwdt_init);
static void __exit vmwdt_exit(void)
{
WARN_ON(misc_deregister(&vmwdt_dev) != 0);
}
module_exit(vmwdt_exit);
|
