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11#define KMSG_COMPONENT "vmwatchdog"
12#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
13
14#include <linux/init.h>
15#include <linux/fs.h>
16#include <linux/kernel.h>
17#include <linux/miscdevice.h>
18#include <linux/module.h>
19#include <linux/moduleparam.h>
20#include <linux/slab.h>
21#include <linux/suspend.h>
22#include <linux/watchdog.h>
23
24#include <asm/ebcdic.h>
25#include <asm/io.h>
26#include <asm/uaccess.h>
27
28#define MAX_CMDLEN 240
29#define MIN_INTERVAL 15
30static char vmwdt_cmd[MAX_CMDLEN] = "IPL";
31static bool vmwdt_conceal;
32
33static bool vmwdt_nowayout = WATCHDOG_NOWAYOUT;
34
35MODULE_LICENSE("GPL");
36MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
37MODULE_DESCRIPTION("z/VM Watchdog Timer");
38module_param_string(cmd, vmwdt_cmd, MAX_CMDLEN, 0644);
39MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers");
40module_param_named(conceal, vmwdt_conceal, bool, 0644);
41MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog "
42 " is active");
43module_param_named(nowayout, vmwdt_nowayout, bool, 0);
44MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
45 " (default=CONFIG_WATCHDOG_NOWAYOUT)");
46MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
47
48static unsigned int vmwdt_interval = 60;
49static unsigned long vmwdt_is_open;
50static int vmwdt_expect_close;
51
52static DEFINE_MUTEX(vmwdt_mutex);
53
54#define VMWDT_OPEN 0
55#define VMWDT_RUNNING 1
56
57enum vmwdt_func {
58
59 wdt_init = 0,
60 wdt_change = 1,
61 wdt_cancel = 2,
62
63 wdt_conceal = 0x80000000,
64};
65
66static int __diag288(enum vmwdt_func func, unsigned int timeout,
67 char *cmd, size_t len)
68{
69 register unsigned long __func asm("2") = func;
70 register unsigned long __timeout asm("3") = timeout;
71 register unsigned long __cmdp asm("4") = virt_to_phys(cmd);
72 register unsigned long __cmdl asm("5") = len;
73 int err;
74
75 err = -EINVAL;
76 asm volatile(
77 " diag %1,%3,0x288\n"
78 "0: la %0,0\n"
79 "1:\n"
80 EX_TABLE(0b,1b)
81 : "+d" (err) : "d"(__func), "d"(__timeout),
82 "d"(__cmdp), "d"(__cmdl) : "1", "cc");
83 return err;
84}
85
86static int vmwdt_keepalive(void)
87{
88
89
90
91
92 static char *ebc_cmd;
93 size_t len;
94 int ret;
95 unsigned int func;
96
97 ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
98 if (!ebc_cmd)
99 return -ENOMEM;
100
101 len = strlcpy(ebc_cmd, vmwdt_cmd, MAX_CMDLEN);
102 ASCEBC(ebc_cmd, MAX_CMDLEN);
103 EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
104
105 func = vmwdt_conceal ? (wdt_init | wdt_conceal) : wdt_init;
106 set_bit(VMWDT_RUNNING, &vmwdt_is_open);
107 ret = __diag288(func, vmwdt_interval, ebc_cmd, len);
108 WARN_ON(ret != 0);
109 kfree(ebc_cmd);
110 return ret;
111}
112
113static int vmwdt_disable(void)
114{
115 char cmd[] = {'\0'};
116 int ret = __diag288(wdt_cancel, 0, cmd, 0);
117 WARN_ON(ret != 0);
118 clear_bit(VMWDT_RUNNING, &vmwdt_is_open);
119 return ret;
120}
121
122static int __init vmwdt_probe(void)
123{
124
125
126
127
128 char ebc_begin[] = {
129 194, 197, 199, 201, 213
130 };
131 if (__diag288(wdt_init, 15, ebc_begin, sizeof(ebc_begin)) != 0)
132 return -EINVAL;
133 return vmwdt_disable();
134}
135
136static int vmwdt_open(struct inode *i, struct file *f)
137{
138 int ret;
139 if (test_and_set_bit(VMWDT_OPEN, &vmwdt_is_open))
140 return -EBUSY;
141 ret = vmwdt_keepalive();
142 if (ret)
143 clear_bit(VMWDT_OPEN, &vmwdt_is_open);
144 return ret ? ret : nonseekable_open(i, f);
145}
146
147static int vmwdt_close(struct inode *i, struct file *f)
148{
149 if (vmwdt_expect_close == 42)
150 vmwdt_disable();
151 vmwdt_expect_close = 0;
152 clear_bit(VMWDT_OPEN, &vmwdt_is_open);
153 return 0;
154}
155
156static struct watchdog_info vmwdt_info = {
157 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
158 .firmware_version = 0,
159 .identity = "z/VM Watchdog Timer",
160};
161
162static int __vmwdt_ioctl(unsigned int cmd, unsigned long arg)
163{
164 switch (cmd) {
165 case WDIOC_GETSUPPORT:
166 if (copy_to_user((void __user *)arg, &vmwdt_info,
167 sizeof(vmwdt_info)))
168 return -EFAULT;
169 return 0;
170 case WDIOC_GETSTATUS:
171 case WDIOC_GETBOOTSTATUS:
172 return put_user(0, (int __user *)arg);
173 case WDIOC_GETTEMP:
174 return -EINVAL;
175 case WDIOC_SETOPTIONS:
176 {
177 int options, ret;
178 if (get_user(options, (int __user *)arg))
179 return -EFAULT;
180 ret = -EINVAL;
181 if (options & WDIOS_DISABLECARD) {
182 ret = vmwdt_disable();
183 if (ret)
184 return ret;
185 }
186 if (options & WDIOS_ENABLECARD) {
187 ret = vmwdt_keepalive();
188 }
189 return ret;
190 }
191 case WDIOC_GETTIMEOUT:
192 return put_user(vmwdt_interval, (int __user *)arg);
193 case WDIOC_SETTIMEOUT:
194 {
195 int interval;
196 if (get_user(interval, (int __user *)arg))
197 return -EFAULT;
198 if (interval < MIN_INTERVAL)
199 return -EINVAL;
200 vmwdt_interval = interval;
201 }
202 return vmwdt_keepalive();
203 case WDIOC_KEEPALIVE:
204 return vmwdt_keepalive();
205 }
206 return -EINVAL;
207}
208
209static long vmwdt_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
210{
211 int rc;
212
213 mutex_lock(&vmwdt_mutex);
214 rc = __vmwdt_ioctl(cmd, arg);
215 mutex_unlock(&vmwdt_mutex);
216 return (long) rc;
217}
218
219static ssize_t vmwdt_write(struct file *f, const char __user *buf,
220 size_t count, loff_t *ppos)
221{
222 if(count) {
223 if (!vmwdt_nowayout) {
224 size_t i;
225
226
227
228 vmwdt_expect_close = 0;
229
230 for (i = 0; i != count; i++) {
231 char c;
232 if (get_user(c, buf+i))
233 return -EFAULT;
234 if (c == 'V')
235 vmwdt_expect_close = 42;
236 }
237 }
238
239 vmwdt_keepalive();
240 }
241 return count;
242}
243
244static int vmwdt_resume(void)
245{
246 clear_bit(VMWDT_OPEN, &vmwdt_is_open);
247 return NOTIFY_DONE;
248}
249
250
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252
253
254
255
256
257static int vmwdt_suspend(void)
258{
259 if (test_and_set_bit(VMWDT_OPEN, &vmwdt_is_open)) {
260 pr_err("The system cannot be suspended while the watchdog"
261 " is in use\n");
262 return notifier_from_errno(-EBUSY);
263 }
264 if (test_bit(VMWDT_RUNNING, &vmwdt_is_open)) {
265 clear_bit(VMWDT_OPEN, &vmwdt_is_open);
266 pr_err("The system cannot be suspended while the watchdog"
267 " is running\n");
268 return notifier_from_errno(-EBUSY);
269 }
270 return NOTIFY_DONE;
271}
272
273
274
275
276static int vmwdt_power_event(struct notifier_block *this, unsigned long event,
277 void *ptr)
278{
279 switch (event) {
280 case PM_POST_HIBERNATION:
281 case PM_POST_SUSPEND:
282 return vmwdt_resume();
283 case PM_HIBERNATION_PREPARE:
284 case PM_SUSPEND_PREPARE:
285 return vmwdt_suspend();
286 default:
287 return NOTIFY_DONE;
288 }
289}
290
291static struct notifier_block vmwdt_power_notifier = {
292 .notifier_call = vmwdt_power_event,
293};
294
295static const struct file_operations vmwdt_fops = {
296 .open = &vmwdt_open,
297 .release = &vmwdt_close,
298 .unlocked_ioctl = &vmwdt_ioctl,
299 .write = &vmwdt_write,
300 .owner = THIS_MODULE,
301 .llseek = noop_llseek,
302};
303
304static struct miscdevice vmwdt_dev = {
305 .minor = WATCHDOG_MINOR,
306 .name = "watchdog",
307 .fops = &vmwdt_fops,
308};
309
310static int __init vmwdt_init(void)
311{
312 int ret;
313
314 ret = vmwdt_probe();
315 if (ret)
316 return ret;
317 ret = register_pm_notifier(&vmwdt_power_notifier);
318 if (ret)
319 return ret;
320
321
322
323
324 ret = misc_register(&vmwdt_dev);
325 if (ret) {
326 unregister_pm_notifier(&vmwdt_power_notifier);
327 return ret;
328 }
329 return 0;
330}
331module_init(vmwdt_init);
332
333static void __exit vmwdt_exit(void)
334{
335 unregister_pm_notifier(&vmwdt_power_notifier);
336 misc_deregister(&vmwdt_dev);
337}
338module_exit(vmwdt_exit);
339
