1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * ipmi_watchdog.c
4 *
5 * A watchdog timer based upon the IPMI interface.
6 *
7 * Author: MontaVista Software, Inc.
8 * Corey Minyard <minyard@mvista.com>
9 * source@mvista.com
10 *
11 * Copyright 2002 MontaVista Software Inc.
12 */
13
14 #define pr_fmt(fmt) "IPMI Watchdog: " fmt
15
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/ipmi.h>
19 #include <linux/ipmi_smi.h>
20 #include <linux/mutex.h>
21 #include <linux/watchdog.h>
22 #include <linux/miscdevice.h>
23 #include <linux/init.h>
24 #include <linux/completion.h>
25 #include <linux/kdebug.h>
26 #include <linux/kstrtox.h>
27 #include <linux/rwsem.h>
28 #include <linux/errno.h>
29 #include <linux/uaccess.h>
30 #include <linux/notifier.h>
31 #include <linux/nmi.h>
32 #include <linux/reboot.h>
33 #include <linux/wait.h>
34 #include <linux/poll.h>
35 #include <linux/string.h>
36 #include <linux/ctype.h>
37 #include <linux/delay.h>
38 #include <linux/atomic.h>
39 #include <linux/sched/signal.h>
40
41 #ifdef CONFIG_X86
42 /*
43 * This is ugly, but I've determined that x86 is the only architecture
44 * that can reasonably support the IPMI NMI watchdog timeout at this
45 * time. If another architecture adds this capability somehow, it
46 * will have to be a somewhat different mechanism and I have no idea
47 * how it will work. So in the unlikely event that another
48 * architecture supports this, we can figure out a good generic
49 * mechanism for it at that time.
50 */
51 #include <asm/kdebug.h>
52 #include <asm/nmi.h>
53 #define HAVE_DIE_NMI
54 #endif
55
56 /*
57 * The IPMI command/response information for the watchdog timer.
58 */
59
60 /* values for byte 1 of the set command, byte 2 of the get response. */
61 #define WDOG_DONT_LOG (1 << 7)
62 #define WDOG_DONT_STOP_ON_SET (1 << 6)
63 #define WDOG_SET_TIMER_USE(byte, use) \
64 byte = ((byte) & 0xf8) | ((use) & 0x7)
65 #define WDOG_GET_TIMER_USE(byte) ((byte) & 0x7)
66 #define WDOG_TIMER_USE_BIOS_FRB2 1
67 #define WDOG_TIMER_USE_BIOS_POST 2
68 #define WDOG_TIMER_USE_OS_LOAD 3
69 #define WDOG_TIMER_USE_SMS_OS 4
70 #define WDOG_TIMER_USE_OEM 5
71
72 /* values for byte 2 of the set command, byte 3 of the get response. */
73 #define WDOG_SET_PRETIMEOUT_ACT(byte, use) \
74 byte = ((byte) & 0x8f) | (((use) & 0x7) << 4)
75 #define WDOG_GET_PRETIMEOUT_ACT(byte) (((byte) >> 4) & 0x7)
76 #define WDOG_PRETIMEOUT_NONE 0
77 #define WDOG_PRETIMEOUT_SMI 1
78 #define WDOG_PRETIMEOUT_NMI 2
79 #define WDOG_PRETIMEOUT_MSG_INT 3
80
81 /* Operations that can be performed on a pretimout. */
82 #define WDOG_PREOP_NONE 0
83 #define WDOG_PREOP_PANIC 1
84 /* Cause data to be available to read. Doesn't work in NMI mode. */
85 #define WDOG_PREOP_GIVE_DATA 2
86
87 /* Actions to perform on a full timeout. */
88 #define WDOG_SET_TIMEOUT_ACT(byte, use) \
89 byte = ((byte) & 0xf8) | ((use) & 0x7)
90 #define WDOG_GET_TIMEOUT_ACT(byte) ((byte) & 0x7)
91 #define WDOG_TIMEOUT_NONE 0
92 #define WDOG_TIMEOUT_RESET 1
93 #define WDOG_TIMEOUT_POWER_DOWN 2
94 #define WDOG_TIMEOUT_POWER_CYCLE 3
95
96 /*
97 * Byte 3 of the get command, byte 4 of the get response is the
98 * pre-timeout in seconds.
99 */
100
101 /* Bits for setting byte 4 of the set command, byte 5 of the get response. */
102 #define WDOG_EXPIRE_CLEAR_BIOS_FRB2 (1 << 1)
103 #define WDOG_EXPIRE_CLEAR_BIOS_POST (1 << 2)
104 #define WDOG_EXPIRE_CLEAR_OS_LOAD (1 << 3)
105 #define WDOG_EXPIRE_CLEAR_SMS_OS (1 << 4)
106 #define WDOG_EXPIRE_CLEAR_OEM (1 << 5)
107
108 /*
109 * Setting/getting the watchdog timer value. This is for bytes 5 and
110 * 6 (the timeout time) of the set command, and bytes 6 and 7 (the
111 * timeout time) and 8 and 9 (the current countdown value) of the
112 * response. The timeout value is given in seconds (in the command it
113 * is 100ms intervals).
114 */
115 #define WDOG_SET_TIMEOUT(byte1, byte2, val) \
116 (byte1) = (((val) * 10) & 0xff), (byte2) = (((val) * 10) >> 8)
117 #define WDOG_GET_TIMEOUT(byte1, byte2) \
118 (((byte1) | ((byte2) << 8)) / 10)
119
120 #define IPMI_WDOG_RESET_TIMER 0x22
121 #define IPMI_WDOG_SET_TIMER 0x24
122 #define IPMI_WDOG_GET_TIMER 0x25
123
124 #define IPMI_WDOG_TIMER_NOT_INIT_RESP 0x80
125
126 static DEFINE_MUTEX(ipmi_watchdog_mutex);
127 static bool nowayout = WATCHDOG_NOWAYOUT;
128
129 static struct ipmi_user *watchdog_user;
130 static int watchdog_ifnum;
131
132 /* Default the timeout to 10 seconds. */
133 static int timeout = 10;
134
135 /* The pre-timeout is disabled by default. */
136 static int pretimeout;
137
138 /* Default timeout to set on panic */
139 static int panic_wdt_timeout = 255;
140
141 /* Default action is to reset the board on a timeout. */
142 static unsigned char action_val = WDOG_TIMEOUT_RESET;
143
144 static char action[16] = "reset";
145
146 static unsigned char preaction_val = WDOG_PRETIMEOUT_NONE;
147
148 static char preaction[16] = "pre_none";
149
150 static unsigned char preop_val = WDOG_PREOP_NONE;
151
152 static char preop[16] = "preop_none";
153 static DEFINE_SPINLOCK(ipmi_read_lock);
154 static char data_to_read;
155 static DECLARE_WAIT_QUEUE_HEAD(read_q);
156 static struct fasync_struct *fasync_q;
157 static atomic_t pretimeout_since_last_heartbeat;
158 static char expect_close;
159
160 static int ifnum_to_use = -1;
161
162 /* Parameters to ipmi_set_timeout */
163 #define IPMI_SET_TIMEOUT_NO_HB 0
164 #define IPMI_SET_TIMEOUT_HB_IF_NECESSARY 1
165 #define IPMI_SET_TIMEOUT_FORCE_HB 2
166
167 static int ipmi_set_timeout(int do_heartbeat);
168 static void ipmi_register_watchdog(int ipmi_intf);
169 static void ipmi_unregister_watchdog(int ipmi_intf);
170
171 /*
172 * If true, the driver will start running as soon as it is configured
173 * and ready.
174 */
175 static int start_now;
176
set_param_timeout(const char * val,const struct kernel_param * kp)177 static int set_param_timeout(const char *val, const struct kernel_param *kp)
178 {
179 char *endp;
180 int l;
181 int rv = 0;
182
183 if (!val)
184 return -EINVAL;
185 l = simple_strtoul(val, &endp, 0);
186 if (endp == val)
187 return -EINVAL;
188
189 *((int *)kp->arg) = l;
190 if (watchdog_user)
191 rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
192
193 return rv;
194 }
195
196 static const struct kernel_param_ops param_ops_timeout = {
197 .set = set_param_timeout,
198 .get = param_get_int,
199 };
200 #define param_check_timeout param_check_int
201
202 typedef int (*action_fn)(const char *intval, char *outval);
203
204 static int action_op(const char *inval, char *outval);
205 static int preaction_op(const char *inval, char *outval);
206 static int preop_op(const char *inval, char *outval);
207 static void check_parms(void);
208
set_param_str(const char * val,const struct kernel_param * kp)209 static int set_param_str(const char *val, const struct kernel_param *kp)
210 {
211 action_fn fn = (action_fn) kp->arg;
212 int rv = 0;
213 char valcp[16];
214 char *s;
215
216 strscpy(valcp, val, 16);
217
218 s = strstrip(valcp);
219
220 rv = fn(s, NULL);
221 if (rv)
222 goto out;
223
224 check_parms();
225 if (watchdog_user)
226 rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
227
228 out:
229 return rv;
230 }
231
get_param_str(char * buffer,const struct kernel_param * kp)232 static int get_param_str(char *buffer, const struct kernel_param *kp)
233 {
234 action_fn fn = (action_fn) kp->arg;
235 int rv, len;
236
237 rv = fn(NULL, buffer);
238 if (rv)
239 return rv;
240
241 len = strlen(buffer);
242 buffer[len++] = '\n';
243 buffer[len] = 0;
244
245 return len;
246 }
247
248
set_param_wdog_ifnum(const char * val,const struct kernel_param * kp)249 static int set_param_wdog_ifnum(const char *val, const struct kernel_param *kp)
250 {
251 int rv = param_set_int(val, kp);
252 if (rv)
253 return rv;
254 if ((ifnum_to_use < 0) || (ifnum_to_use == watchdog_ifnum))
255 return 0;
256
257 ipmi_unregister_watchdog(watchdog_ifnum);
258 ipmi_register_watchdog(ifnum_to_use);
259 return 0;
260 }
261
262 static const struct kernel_param_ops param_ops_wdog_ifnum = {
263 .set = set_param_wdog_ifnum,
264 .get = param_get_int,
265 };
266
267 #define param_check_wdog_ifnum param_check_int
268
269 static const struct kernel_param_ops param_ops_str = {
270 .set = set_param_str,
271 .get = get_param_str,
272 };
273
274 module_param(ifnum_to_use, wdog_ifnum, 0644);
275 MODULE_PARM_DESC(ifnum_to_use, "The interface number to use for the watchdog "
276 "timer. Setting to -1 defaults to the first registered "
277 "interface");
278
279 module_param(timeout, timeout, 0644);
280 MODULE_PARM_DESC(timeout, "Timeout value in seconds.");
281
282 module_param(pretimeout, timeout, 0644);
283 MODULE_PARM_DESC(pretimeout, "Pretimeout value in seconds.");
284
285 module_param(panic_wdt_timeout, timeout, 0644);
286 MODULE_PARM_DESC(panic_wdt_timeout, "Timeout value on kernel panic in seconds.");
287
288 module_param_cb(action, ¶m_ops_str, action_op, 0644);
289 MODULE_PARM_DESC(action, "Timeout action. One of: "
290 "reset, none, power_cycle, power_off.");
291
292 module_param_cb(preaction, ¶m_ops_str, preaction_op, 0644);
293 MODULE_PARM_DESC(preaction, "Pretimeout action. One of: "
294 "pre_none, pre_smi, pre_nmi, pre_int.");
295
296 module_param_cb(preop, ¶m_ops_str, preop_op, 0644);
297 MODULE_PARM_DESC(preop, "Pretimeout driver operation. One of: "
298 "preop_none, preop_panic, preop_give_data.");
299
300 module_param(start_now, int, 0444);
301 MODULE_PARM_DESC(start_now, "Set to 1 to start the watchdog as"
302 "soon as the driver is loaded.");
303
304 module_param(nowayout, bool, 0644);
305 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
306 "(default=CONFIG_WATCHDOG_NOWAYOUT)");
307
308 /* Default state of the timer. */
309 static unsigned char ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
310
311 /* Is someone using the watchdog? Only one user is allowed. */
312 static unsigned long ipmi_wdog_open;
313
314 /*
315 * If set to 1, the heartbeat command will set the state to reset and
316 * start the timer. The timer doesn't normally run when the driver is
317 * first opened until the heartbeat is set the first time, this
318 * variable is used to accomplish this.
319 */
320 static int ipmi_start_timer_on_heartbeat;
321
322 /* IPMI version of the BMC. */
323 static unsigned char ipmi_version_major;
324 static unsigned char ipmi_version_minor;
325
326 /* If a pretimeout occurs, this is used to allow only one panic to happen. */
327 static atomic_t preop_panic_excl = ATOMIC_INIT(-1);
328
329 #ifdef HAVE_DIE_NMI
330 static int testing_nmi;
331 static int nmi_handler_registered;
332 #endif
333
334 static int __ipmi_heartbeat(void);
335
336 /*
337 * We use a mutex to make sure that only one thing can send a set a
338 * message at one time. The mutex is claimed when a message is sent
339 * and freed when both the send and receive messages are free.
340 */
341 static atomic_t msg_tofree = ATOMIC_INIT(0);
342 static DECLARE_COMPLETION(msg_wait);
msg_free_smi(struct ipmi_smi_msg * msg)343 static void msg_free_smi(struct ipmi_smi_msg *msg)
344 {
345 if (atomic_dec_and_test(&msg_tofree)) {
346 if (!oops_in_progress)
347 complete(&msg_wait);
348 }
349 }
msg_free_recv(struct ipmi_recv_msg * msg)350 static void msg_free_recv(struct ipmi_recv_msg *msg)
351 {
352 if (atomic_dec_and_test(&msg_tofree)) {
353 if (!oops_in_progress)
354 complete(&msg_wait);
355 }
356 }
357 static struct ipmi_smi_msg smi_msg = INIT_IPMI_SMI_MSG(msg_free_smi);
358 static struct ipmi_recv_msg recv_msg = INIT_IPMI_RECV_MSG(msg_free_recv);
359
__ipmi_set_timeout(struct ipmi_smi_msg * smi_msg,struct ipmi_recv_msg * recv_msg,int * send_heartbeat_now)360 static int __ipmi_set_timeout(struct ipmi_smi_msg *smi_msg,
361 struct ipmi_recv_msg *recv_msg,
362 int *send_heartbeat_now)
363 {
364 struct kernel_ipmi_msg msg;
365 unsigned char data[6];
366 int rv;
367 struct ipmi_system_interface_addr addr;
368 int hbnow = 0;
369
370
371 data[0] = 0;
372 WDOG_SET_TIMER_USE(data[0], WDOG_TIMER_USE_SMS_OS);
373
374 if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
375 if ((ipmi_version_major > 1) ||
376 ((ipmi_version_major == 1) && (ipmi_version_minor >= 5))) {
377 /* This is an IPMI 1.5-only feature. */
378 data[0] |= WDOG_DONT_STOP_ON_SET;
379 } else {
380 /*
381 * In ipmi 1.0, setting the timer stops the watchdog, we
382 * need to start it back up again.
383 */
384 hbnow = 1;
385 }
386 }
387
388 data[1] = 0;
389 WDOG_SET_TIMEOUT_ACT(data[1], ipmi_watchdog_state);
390 if ((pretimeout > 0) && (ipmi_watchdog_state != WDOG_TIMEOUT_NONE)) {
391 WDOG_SET_PRETIMEOUT_ACT(data[1], preaction_val);
392 data[2] = pretimeout;
393 } else {
394 WDOG_SET_PRETIMEOUT_ACT(data[1], WDOG_PRETIMEOUT_NONE);
395 data[2] = 0; /* No pretimeout. */
396 }
397 data[3] = 0;
398 WDOG_SET_TIMEOUT(data[4], data[5], timeout);
399
400 addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
401 addr.channel = IPMI_BMC_CHANNEL;
402 addr.lun = 0;
403
404 msg.netfn = 0x06;
405 msg.cmd = IPMI_WDOG_SET_TIMER;
406 msg.data = data;
407 msg.data_len = sizeof(data);
408 rv = ipmi_request_supply_msgs(watchdog_user,
409 (struct ipmi_addr *) &addr,
410 0,
411 &msg,
412 NULL,
413 smi_msg,
414 recv_msg,
415 1);
416 if (rv)
417 pr_warn("set timeout error: %d\n", rv);
418 else if (send_heartbeat_now)
419 *send_heartbeat_now = hbnow;
420
421 return rv;
422 }
423
_ipmi_set_timeout(int do_heartbeat)424 static int _ipmi_set_timeout(int do_heartbeat)
425 {
426 int send_heartbeat_now;
427 int rv;
428
429 if (!watchdog_user)
430 return -ENODEV;
431
432 atomic_set(&msg_tofree, 2);
433
434 rv = __ipmi_set_timeout(&smi_msg,
435 &recv_msg,
436 &send_heartbeat_now);
437 if (rv) {
438 atomic_set(&msg_tofree, 0);
439 return rv;
440 }
441
442 wait_for_completion(&msg_wait);
443
444 if ((do_heartbeat == IPMI_SET_TIMEOUT_FORCE_HB)
445 || ((send_heartbeat_now)
446 && (do_heartbeat == IPMI_SET_TIMEOUT_HB_IF_NECESSARY)))
447 rv = __ipmi_heartbeat();
448
449 return rv;
450 }
451
ipmi_set_timeout(int do_heartbeat)452 static int ipmi_set_timeout(int do_heartbeat)
453 {
454 int rv;
455
456 mutex_lock(&ipmi_watchdog_mutex);
457 rv = _ipmi_set_timeout(do_heartbeat);
458 mutex_unlock(&ipmi_watchdog_mutex);
459
460 return rv;
461 }
462
463 static atomic_t panic_done_count = ATOMIC_INIT(0);
464
panic_smi_free(struct ipmi_smi_msg * msg)465 static void panic_smi_free(struct ipmi_smi_msg *msg)
466 {
467 atomic_dec(&panic_done_count);
468 }
panic_recv_free(struct ipmi_recv_msg * msg)469 static void panic_recv_free(struct ipmi_recv_msg *msg)
470 {
471 atomic_dec(&panic_done_count);
472 }
473
474 static struct ipmi_smi_msg panic_halt_heartbeat_smi_msg =
475 INIT_IPMI_SMI_MSG(panic_smi_free);
476 static struct ipmi_recv_msg panic_halt_heartbeat_recv_msg =
477 INIT_IPMI_RECV_MSG(panic_recv_free);
478
panic_halt_ipmi_heartbeat(void)479 static void panic_halt_ipmi_heartbeat(void)
480 {
481 struct kernel_ipmi_msg msg;
482 struct ipmi_system_interface_addr addr;
483 int rv;
484
485 /*
486 * Don't reset the timer if we have the timer turned off, that
487 * re-enables the watchdog.
488 */
489 if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
490 return;
491
492 addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
493 addr.channel = IPMI_BMC_CHANNEL;
494 addr.lun = 0;
495
496 msg.netfn = 0x06;
497 msg.cmd = IPMI_WDOG_RESET_TIMER;
498 msg.data = NULL;
499 msg.data_len = 0;
500 atomic_add(2, &panic_done_count);
501 rv = ipmi_request_supply_msgs(watchdog_user,
502 (struct ipmi_addr *) &addr,
503 0,
504 &msg,
505 NULL,
506 &panic_halt_heartbeat_smi_msg,
507 &panic_halt_heartbeat_recv_msg,
508 1);
509 if (rv)
510 atomic_sub(2, &panic_done_count);
511 }
512
513 static struct ipmi_smi_msg panic_halt_smi_msg =
514 INIT_IPMI_SMI_MSG(panic_smi_free);
515 static struct ipmi_recv_msg panic_halt_recv_msg =
516 INIT_IPMI_RECV_MSG(panic_recv_free);
517
518 /*
519 * Special call, doesn't claim any locks. This is only to be called
520 * at panic or halt time, in run-to-completion mode, when the caller
521 * is the only CPU and the only thing that will be going is these IPMI
522 * calls.
523 */
panic_halt_ipmi_set_timeout(void)524 static void panic_halt_ipmi_set_timeout(void)
525 {
526 int send_heartbeat_now;
527 int rv;
528
529 /* Wait for the messages to be free. */
530 while (atomic_read(&panic_done_count) != 0)
531 ipmi_poll_interface(watchdog_user);
532 atomic_add(2, &panic_done_count);
533 rv = __ipmi_set_timeout(&panic_halt_smi_msg,
534 &panic_halt_recv_msg,
535 &send_heartbeat_now);
536 if (rv) {
537 atomic_sub(2, &panic_done_count);
538 pr_warn("Unable to extend the watchdog timeout\n");
539 } else {
540 if (send_heartbeat_now)
541 panic_halt_ipmi_heartbeat();
542 }
543 while (atomic_read(&panic_done_count) != 0)
544 ipmi_poll_interface(watchdog_user);
545 }
546
__ipmi_heartbeat(void)547 static int __ipmi_heartbeat(void)
548 {
549 struct kernel_ipmi_msg msg;
550 int rv;
551 struct ipmi_system_interface_addr addr;
552 int timeout_retries = 0;
553
554 restart:
555 /*
556 * Don't reset the timer if we have the timer turned off, that
557 * re-enables the watchdog.
558 */
559 if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
560 return 0;
561
562 atomic_set(&msg_tofree, 2);
563
564 addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
565 addr.channel = IPMI_BMC_CHANNEL;
566 addr.lun = 0;
567
568 msg.netfn = 0x06;
569 msg.cmd = IPMI_WDOG_RESET_TIMER;
570 msg.data = NULL;
571 msg.data_len = 0;
572 rv = ipmi_request_supply_msgs(watchdog_user,
573 (struct ipmi_addr *) &addr,
574 0,
575 &msg,
576 NULL,
577 &smi_msg,
578 &recv_msg,
579 1);
580 if (rv) {
581 atomic_set(&msg_tofree, 0);
582 pr_warn("heartbeat send failure: %d\n", rv);
583 return rv;
584 }
585
586 /* Wait for the heartbeat to be sent. */
587 wait_for_completion(&msg_wait);
588
589 if (recv_msg.msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP) {
590 timeout_retries++;
591 if (timeout_retries > 3) {
592 pr_err("Unable to restore the IPMI watchdog's settings, giving up\n");
593 rv = -EIO;
594 goto out;
595 }
596
597 /*
598 * The timer was not initialized, that means the BMC was
599 * probably reset and lost the watchdog information. Attempt
600 * to restore the timer's info. Note that we still hold
601 * the heartbeat lock, to keep a heartbeat from happening
602 * in this process, so must say no heartbeat to avoid a
603 * deadlock on this mutex
604 */
605 rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
606 if (rv) {
607 pr_err("Unable to send the command to set the watchdog's settings, giving up\n");
608 goto out;
609 }
610
611 /* Might need a heartbeat send, go ahead and do it. */
612 goto restart;
613 } else if (recv_msg.msg.data[0] != 0) {
614 /*
615 * Got an error in the heartbeat response. It was already
616 * reported in ipmi_wdog_msg_handler, but we should return
617 * an error here.
618 */
619 rv = -EINVAL;
620 }
621
622 out:
623 return rv;
624 }
625
_ipmi_heartbeat(void)626 static int _ipmi_heartbeat(void)
627 {
628 int rv;
629
630 if (!watchdog_user)
631 return -ENODEV;
632
633 if (ipmi_start_timer_on_heartbeat) {
634 ipmi_start_timer_on_heartbeat = 0;
635 ipmi_watchdog_state = action_val;
636 rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
637 } else if (atomic_cmpxchg(&pretimeout_since_last_heartbeat, 1, 0)) {
638 /*
639 * A pretimeout occurred, make sure we set the timeout.
640 * We don't want to set the action, though, we want to
641 * leave that alone (thus it can't be combined with the
642 * above operation.
643 */
644 rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
645 } else {
646 rv = __ipmi_heartbeat();
647 }
648
649 return rv;
650 }
651
ipmi_heartbeat(void)652 static int ipmi_heartbeat(void)
653 {
654 int rv;
655
656 mutex_lock(&ipmi_watchdog_mutex);
657 rv = _ipmi_heartbeat();
658 mutex_unlock(&ipmi_watchdog_mutex);
659
660 return rv;
661 }
662
663 static const struct watchdog_info ident = {
664 .options = 0, /* WDIOF_SETTIMEOUT, */
665 .firmware_version = 1,
666 .identity = "IPMI"
667 };
668
ipmi_ioctl(struct file * file,unsigned int cmd,unsigned long arg)669 static int ipmi_ioctl(struct file *file,
670 unsigned int cmd, unsigned long arg)
671 {
672 void __user *argp = (void __user *)arg;
673 int i;
674 int val;
675
676 switch (cmd) {
677 case WDIOC_GETSUPPORT:
678 i = copy_to_user(argp, &ident, sizeof(ident));
679 return i ? -EFAULT : 0;
680
681 case WDIOC_SETTIMEOUT:
682 i = copy_from_user(&val, argp, sizeof(int));
683 if (i)
684 return -EFAULT;
685 timeout = val;
686 return _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
687
688 case WDIOC_GETTIMEOUT:
689 i = copy_to_user(argp, &timeout, sizeof(timeout));
690 if (i)
691 return -EFAULT;
692 return 0;
693
694 case WDIOC_SETPRETIMEOUT:
695 i = copy_from_user(&val, argp, sizeof(int));
696 if (i)
697 return -EFAULT;
698 pretimeout = val;
699 return _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
700
701 case WDIOC_GETPRETIMEOUT:
702 i = copy_to_user(argp, &pretimeout, sizeof(pretimeout));
703 if (i)
704 return -EFAULT;
705 return 0;
706
707 case WDIOC_KEEPALIVE:
708 return _ipmi_heartbeat();
709
710 case WDIOC_SETOPTIONS:
711 i = copy_from_user(&val, argp, sizeof(int));
712 if (i)
713 return -EFAULT;
714 if (val & WDIOS_DISABLECARD) {
715 ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
716 _ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
717 ipmi_start_timer_on_heartbeat = 0;
718 }
719
720 if (val & WDIOS_ENABLECARD) {
721 ipmi_watchdog_state = action_val;
722 _ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
723 }
724 return 0;
725
726 case WDIOC_GETSTATUS:
727 val = 0;
728 i = copy_to_user(argp, &val, sizeof(val));
729 if (i)
730 return -EFAULT;
731 return 0;
732
733 default:
734 return -ENOIOCTLCMD;
735 }
736 }
737
ipmi_unlocked_ioctl(struct file * file,unsigned int cmd,unsigned long arg)738 static long ipmi_unlocked_ioctl(struct file *file,
739 unsigned int cmd,
740 unsigned long arg)
741 {
742 int ret;
743
744 mutex_lock(&ipmi_watchdog_mutex);
745 ret = ipmi_ioctl(file, cmd, arg);
746 mutex_unlock(&ipmi_watchdog_mutex);
747
748 return ret;
749 }
750
ipmi_write(struct file * file,const char __user * buf,size_t len,loff_t * ppos)751 static ssize_t ipmi_write(struct file *file,
752 const char __user *buf,
753 size_t len,
754 loff_t *ppos)
755 {
756 int rv;
757
758 if (len) {
759 if (!nowayout) {
760 size_t i;
761
762 /* In case it was set long ago */
763 expect_close = 0;
764
765 for (i = 0; i != len; i++) {
766 char c;
767
768 if (get_user(c, buf + i))
769 return -EFAULT;
770 if (c == 'V')
771 expect_close = 42;
772 }
773 }
774 rv = ipmi_heartbeat();
775 if (rv)
776 return rv;
777 }
778 return len;
779 }
780
ipmi_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)781 static ssize_t ipmi_read(struct file *file,
782 char __user *buf,
783 size_t count,
784 loff_t *ppos)
785 {
786 int rv = 0;
787 wait_queue_entry_t wait;
788
789 if (count <= 0)
790 return 0;
791
792 /*
793 * Reading returns if the pretimeout has gone off, and it only does
794 * it once per pretimeout.
795 */
796 spin_lock_irq(&ipmi_read_lock);
797 if (!data_to_read) {
798 if (file->f_flags & O_NONBLOCK) {
799 rv = -EAGAIN;
800 goto out;
801 }
802
803 init_waitqueue_entry(&wait, current);
804 add_wait_queue(&read_q, &wait);
805 while (!data_to_read && !signal_pending(current)) {
806 set_current_state(TASK_INTERRUPTIBLE);
807 spin_unlock_irq(&ipmi_read_lock);
808 schedule();
809 spin_lock_irq(&ipmi_read_lock);
810 }
811 remove_wait_queue(&read_q, &wait);
812
813 if (signal_pending(current)) {
814 rv = -ERESTARTSYS;
815 goto out;
816 }
817 }
818 data_to_read = 0;
819
820 out:
821 spin_unlock_irq(&ipmi_read_lock);
822
823 if (rv == 0) {
824 if (copy_to_user(buf, &data_to_read, 1))
825 rv = -EFAULT;
826 else
827 rv = 1;
828 }
829
830 return rv;
831 }
832
ipmi_open(struct inode * ino,struct file * filep)833 static int ipmi_open(struct inode *ino, struct file *filep)
834 {
835 switch (iminor(ino)) {
836 case WATCHDOG_MINOR:
837 if (test_and_set_bit(0, &ipmi_wdog_open))
838 return -EBUSY;
839
840
841 /*
842 * Don't start the timer now, let it start on the
843 * first heartbeat.
844 */
845 ipmi_start_timer_on_heartbeat = 1;
846 return stream_open(ino, filep);
847
848 default:
849 return (-ENODEV);
850 }
851 }
852
ipmi_poll(struct file * file,poll_table * wait)853 static __poll_t ipmi_poll(struct file *file, poll_table *wait)
854 {
855 __poll_t mask = 0;
856
857 poll_wait(file, &read_q, wait);
858
859 spin_lock_irq(&ipmi_read_lock);
860 if (data_to_read)
861 mask |= (EPOLLIN | EPOLLRDNORM);
862 spin_unlock_irq(&ipmi_read_lock);
863
864 return mask;
865 }
866
ipmi_fasync(int fd,struct file * file,int on)867 static int ipmi_fasync(int fd, struct file *file, int on)
868 {
869 int result;
870
871 result = fasync_helper(fd, file, on, &fasync_q);
872
873 return (result);
874 }
875
ipmi_close(struct inode * ino,struct file * filep)876 static int ipmi_close(struct inode *ino, struct file *filep)
877 {
878 if (iminor(ino) == WATCHDOG_MINOR) {
879 if (expect_close == 42) {
880 mutex_lock(&ipmi_watchdog_mutex);
881 ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
882 _ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
883 mutex_unlock(&ipmi_watchdog_mutex);
884 } else {
885 pr_crit("Unexpected close, not stopping watchdog!\n");
886 ipmi_heartbeat();
887 }
888 clear_bit(0, &ipmi_wdog_open);
889 }
890
891 expect_close = 0;
892
893 return 0;
894 }
895
896 static const struct file_operations ipmi_wdog_fops = {
897 .owner = THIS_MODULE,
898 .read = ipmi_read,
899 .poll = ipmi_poll,
900 .write = ipmi_write,
901 .unlocked_ioctl = ipmi_unlocked_ioctl,
902 .compat_ioctl = compat_ptr_ioctl,
903 .open = ipmi_open,
904 .release = ipmi_close,
905 .fasync = ipmi_fasync,
906 };
907
908 static struct miscdevice ipmi_wdog_miscdev = {
909 .minor = WATCHDOG_MINOR,
910 .name = "watchdog",
911 .fops = &ipmi_wdog_fops
912 };
913
ipmi_wdog_msg_handler(struct ipmi_recv_msg * msg,void * handler_data)914 static void ipmi_wdog_msg_handler(struct ipmi_recv_msg *msg,
915 void *handler_data)
916 {
917 if (msg->msg.cmd == IPMI_WDOG_RESET_TIMER &&
918 msg->msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)
919 pr_info("response: The IPMI controller appears to have been reset, will attempt to reinitialize the watchdog timer\n");
920 else if (msg->msg.data[0] != 0)
921 pr_err("response: Error %x on cmd %x\n",
922 msg->msg.data[0],
923 msg->msg.cmd);
924
925 ipmi_free_recv_msg(msg);
926 }
927
ipmi_wdog_pretimeout_handler(void * handler_data)928 static void ipmi_wdog_pretimeout_handler(void *handler_data)
929 {
930 if (preaction_val != WDOG_PRETIMEOUT_NONE) {
931 if (preop_val == WDOG_PREOP_PANIC) {
932 if (atomic_inc_and_test(&preop_panic_excl))
933 panic("Watchdog pre-timeout");
934 } else if (preop_val == WDOG_PREOP_GIVE_DATA) {
935 unsigned long flags;
936
937 spin_lock_irqsave(&ipmi_read_lock, flags);
938 data_to_read = 1;
939 wake_up_interruptible(&read_q);
940 kill_fasync(&fasync_q, SIGIO, POLL_IN);
941 spin_unlock_irqrestore(&ipmi_read_lock, flags);
942 }
943 }
944
945 /*
946 * On some machines, the heartbeat will give an error and not
947 * work unless we re-enable the timer. So do so.
948 */
949 atomic_set(&pretimeout_since_last_heartbeat, 1);
950 }
951
ipmi_wdog_panic_handler(void * user_data)952 static void ipmi_wdog_panic_handler(void *user_data)
953 {
954 static int panic_event_handled;
955
956 /*
957 * On a panic, if we have a panic timeout, make sure to extend
958 * the watchdog timer to a reasonable value to complete the
959 * panic, if the watchdog timer is running. Plus the
960 * pretimeout is meaningless at panic time.
961 */
962 if (watchdog_user && !panic_event_handled &&
963 ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
964 /* Make sure we do this only once. */
965 panic_event_handled = 1;
966
967 timeout = panic_wdt_timeout;
968 pretimeout = 0;
969 panic_halt_ipmi_set_timeout();
970 }
971 }
972
973 static const struct ipmi_user_hndl ipmi_hndlrs = {
974 .ipmi_recv_hndl = ipmi_wdog_msg_handler,
975 .ipmi_watchdog_pretimeout = ipmi_wdog_pretimeout_handler,
976 .ipmi_panic_handler = ipmi_wdog_panic_handler
977 };
978
ipmi_register_watchdog(int ipmi_intf)979 static void ipmi_register_watchdog(int ipmi_intf)
980 {
981 int rv = -EBUSY;
982
983 if (watchdog_user)
984 goto out;
985
986 if ((ifnum_to_use >= 0) && (ifnum_to_use != ipmi_intf))
987 goto out;
988
989 watchdog_ifnum = ipmi_intf;
990
991 rv = ipmi_create_user(ipmi_intf, &ipmi_hndlrs, NULL, &watchdog_user);
992 if (rv < 0) {
993 pr_crit("Unable to register with ipmi\n");
994 goto out;
995 }
996
997 rv = ipmi_get_version(watchdog_user,
998 &ipmi_version_major,
999 &ipmi_version_minor);
1000 if (rv) {
1001 pr_warn("Unable to get IPMI version, assuming 1.0\n");
1002 ipmi_version_major = 1;
1003 ipmi_version_minor = 0;
1004 }
1005
1006 rv = misc_register(&ipmi_wdog_miscdev);
1007 if (rv < 0) {
1008 ipmi_destroy_user(watchdog_user);
1009 watchdog_user = NULL;
1010 pr_crit("Unable to register misc device\n");
1011 }
1012
1013 #ifdef HAVE_DIE_NMI
1014 if (nmi_handler_registered) {
1015 int old_pretimeout = pretimeout;
1016 int old_timeout = timeout;
1017 int old_preop_val = preop_val;
1018
1019 /*
1020 * Set the pretimeout to go off in a second and give
1021 * ourselves plenty of time to stop the timer.
1022 */
1023 ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
1024 preop_val = WDOG_PREOP_NONE; /* Make sure nothing happens */
1025 pretimeout = 99;
1026 timeout = 100;
1027
1028 testing_nmi = 1;
1029
1030 rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
1031 if (rv) {
1032 pr_warn("Error starting timer to test NMI: 0x%x. The NMI pretimeout will likely not work\n",
1033 rv);
1034 rv = 0;
1035 goto out_restore;
1036 }
1037
1038 msleep(1500);
1039
1040 if (testing_nmi != 2) {
1041 pr_warn("IPMI NMI didn't seem to occur. The NMI pretimeout will likely not work\n");
1042 }
1043 out_restore:
1044 testing_nmi = 0;
1045 preop_val = old_preop_val;
1046 pretimeout = old_pretimeout;
1047 timeout = old_timeout;
1048 }
1049 #endif
1050
1051 out:
1052 if ((start_now) && (rv == 0)) {
1053 /* Run from startup, so start the timer now. */
1054 start_now = 0; /* Disable this function after first startup. */
1055 ipmi_watchdog_state = action_val;
1056 ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
1057 pr_info("Starting now!\n");
1058 } else {
1059 /* Stop the timer now. */
1060 ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
1061 ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
1062 }
1063 }
1064
ipmi_unregister_watchdog(int ipmi_intf)1065 static void ipmi_unregister_watchdog(int ipmi_intf)
1066 {
1067 int rv;
1068 struct ipmi_user *loc_user = watchdog_user;
1069
1070 if (!loc_user)
1071 return;
1072
1073 if (watchdog_ifnum != ipmi_intf)
1074 return;
1075
1076 /* Make sure no one can call us any more. */
1077 misc_deregister(&ipmi_wdog_miscdev);
1078
1079 watchdog_user = NULL;
1080
1081 /*
1082 * Wait to make sure the message makes it out. The lower layer has
1083 * pointers to our buffers, we want to make sure they are done before
1084 * we release our memory.
1085 */
1086 while (atomic_read(&msg_tofree))
1087 msg_free_smi(NULL);
1088
1089 mutex_lock(&ipmi_watchdog_mutex);
1090
1091 /* Disconnect from IPMI. */
1092 rv = ipmi_destroy_user(loc_user);
1093 if (rv)
1094 pr_warn("error unlinking from IPMI: %d\n", rv);
1095
1096 /* If it comes back, restart it properly. */
1097 ipmi_start_timer_on_heartbeat = 1;
1098
1099 mutex_unlock(&ipmi_watchdog_mutex);
1100 }
1101
1102 #ifdef HAVE_DIE_NMI
1103 static int
ipmi_nmi(unsigned int val,struct pt_regs * regs)1104 ipmi_nmi(unsigned int val, struct pt_regs *regs)
1105 {
1106 /*
1107 * If we get here, it's an NMI that's not a memory or I/O
1108 * error. We can't truly tell if it's from IPMI or not
1109 * without sending a message, and sending a message is almost
1110 * impossible because of locking.
1111 */
1112
1113 if (testing_nmi) {
1114 testing_nmi = 2;
1115 return NMI_HANDLED;
1116 }
1117
1118 /* If we are not expecting a timeout, ignore it. */
1119 if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
1120 return NMI_DONE;
1121
1122 if (preaction_val != WDOG_PRETIMEOUT_NMI)
1123 return NMI_DONE;
1124
1125 /*
1126 * If no one else handled the NMI, we assume it was the IPMI
1127 * watchdog.
1128 */
1129 if (preop_val == WDOG_PREOP_PANIC) {
1130 /* On some machines, the heartbeat will give
1131 an error and not work unless we re-enable
1132 the timer. So do so. */
1133 atomic_set(&pretimeout_since_last_heartbeat, 1);
1134 if (atomic_inc_and_test(&preop_panic_excl))
1135 nmi_panic(regs, "pre-timeout");
1136 }
1137
1138 return NMI_HANDLED;
1139 }
1140 #endif
1141
wdog_reboot_handler(struct notifier_block * this,unsigned long code,void * unused)1142 static int wdog_reboot_handler(struct notifier_block *this,
1143 unsigned long code,
1144 void *unused)
1145 {
1146 static int reboot_event_handled;
1147
1148 if ((watchdog_user) && (!reboot_event_handled)) {
1149 /* Make sure we only do this once. */
1150 reboot_event_handled = 1;
1151
1152 if (code == SYS_POWER_OFF || code == SYS_HALT) {
1153 /* Disable the WDT if we are shutting down. */
1154 ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
1155 ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
1156 } else if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
1157 /* Set a long timer to let the reboot happen or
1158 reset if it hangs, but only if the watchdog
1159 timer was already running. */
1160 if (timeout < 120)
1161 timeout = 120;
1162 pretimeout = 0;
1163 ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
1164 ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
1165 }
1166 }
1167 return NOTIFY_OK;
1168 }
1169
1170 static struct notifier_block wdog_reboot_notifier = {
1171 .notifier_call = wdog_reboot_handler,
1172 .next = NULL,
1173 .priority = 0
1174 };
1175
ipmi_new_smi(int if_num,struct device * device)1176 static void ipmi_new_smi(int if_num, struct device *device)
1177 {
1178 ipmi_register_watchdog(if_num);
1179 }
1180
ipmi_smi_gone(int if_num)1181 static void ipmi_smi_gone(int if_num)
1182 {
1183 ipmi_unregister_watchdog(if_num);
1184 }
1185
1186 static struct ipmi_smi_watcher smi_watcher = {
1187 .owner = THIS_MODULE,
1188 .new_smi = ipmi_new_smi,
1189 .smi_gone = ipmi_smi_gone
1190 };
1191
action_op(const char * inval,char * outval)1192 static int action_op(const char *inval, char *outval)
1193 {
1194 if (outval)
1195 strcpy(outval, action);
1196
1197 if (!inval)
1198 return 0;
1199
1200 if (strcmp(inval, "reset") == 0)
1201 action_val = WDOG_TIMEOUT_RESET;
1202 else if (strcmp(inval, "none") == 0)
1203 action_val = WDOG_TIMEOUT_NONE;
1204 else if (strcmp(inval, "power_cycle") == 0)
1205 action_val = WDOG_TIMEOUT_POWER_CYCLE;
1206 else if (strcmp(inval, "power_off") == 0)
1207 action_val = WDOG_TIMEOUT_POWER_DOWN;
1208 else
1209 return -EINVAL;
1210 strcpy(action, inval);
1211 return 0;
1212 }
1213
preaction_op(const char * inval,char * outval)1214 static int preaction_op(const char *inval, char *outval)
1215 {
1216 if (outval)
1217 strcpy(outval, preaction);
1218
1219 if (!inval)
1220 return 0;
1221
1222 if (strcmp(inval, "pre_none") == 0)
1223 preaction_val = WDOG_PRETIMEOUT_NONE;
1224 else if (strcmp(inval, "pre_smi") == 0)
1225 preaction_val = WDOG_PRETIMEOUT_SMI;
1226 #ifdef HAVE_DIE_NMI
1227 else if (strcmp(inval, "pre_nmi") == 0)
1228 preaction_val = WDOG_PRETIMEOUT_NMI;
1229 #endif
1230 else if (strcmp(inval, "pre_int") == 0)
1231 preaction_val = WDOG_PRETIMEOUT_MSG_INT;
1232 else
1233 return -EINVAL;
1234 strcpy(preaction, inval);
1235 return 0;
1236 }
1237
preop_op(const char * inval,char * outval)1238 static int preop_op(const char *inval, char *outval)
1239 {
1240 if (outval)
1241 strcpy(outval, preop);
1242
1243 if (!inval)
1244 return 0;
1245
1246 if (strcmp(inval, "preop_none") == 0)
1247 preop_val = WDOG_PREOP_NONE;
1248 else if (strcmp(inval, "preop_panic") == 0)
1249 preop_val = WDOG_PREOP_PANIC;
1250 else if (strcmp(inval, "preop_give_data") == 0)
1251 preop_val = WDOG_PREOP_GIVE_DATA;
1252 else
1253 return -EINVAL;
1254 strcpy(preop, inval);
1255 return 0;
1256 }
1257
check_parms(void)1258 static void check_parms(void)
1259 {
1260 #ifdef HAVE_DIE_NMI
1261 int do_nmi = 0;
1262 int rv;
1263
1264 if (preaction_val == WDOG_PRETIMEOUT_NMI) {
1265 do_nmi = 1;
1266 if (preop_val == WDOG_PREOP_GIVE_DATA) {
1267 pr_warn("Pretimeout op is to give data but NMI pretimeout is enabled, setting pretimeout op to none\n");
1268 preop_op("preop_none", NULL);
1269 do_nmi = 0;
1270 }
1271 }
1272 if (do_nmi && !nmi_handler_registered) {
1273 rv = register_nmi_handler(NMI_UNKNOWN, ipmi_nmi, 0,
1274 "ipmi");
1275 if (rv) {
1276 pr_warn("Can't register nmi handler\n");
1277 return;
1278 } else
1279 nmi_handler_registered = 1;
1280 } else if (!do_nmi && nmi_handler_registered) {
1281 unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
1282 nmi_handler_registered = 0;
1283 }
1284 #endif
1285 }
1286
ipmi_wdog_init(void)1287 static int __init ipmi_wdog_init(void)
1288 {
1289 int rv;
1290
1291 if (action_op(action, NULL)) {
1292 action_op("reset", NULL);
1293 pr_info("Unknown action '%s', defaulting to reset\n", action);
1294 }
1295
1296 if (preaction_op(preaction, NULL)) {
1297 preaction_op("pre_none", NULL);
1298 pr_info("Unknown preaction '%s', defaulting to none\n",
1299 preaction);
1300 }
1301
1302 if (preop_op(preop, NULL)) {
1303 preop_op("preop_none", NULL);
1304 pr_info("Unknown preop '%s', defaulting to none\n", preop);
1305 }
1306
1307 check_parms();
1308
1309 register_reboot_notifier(&wdog_reboot_notifier);
1310
1311 rv = ipmi_smi_watcher_register(&smi_watcher);
1312 if (rv) {
1313 #ifdef HAVE_DIE_NMI
1314 if (nmi_handler_registered)
1315 unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
1316 #endif
1317 unregister_reboot_notifier(&wdog_reboot_notifier);
1318 pr_warn("can't register smi watcher\n");
1319 return rv;
1320 }
1321
1322 pr_info("driver initialized\n");
1323
1324 return 0;
1325 }
1326
ipmi_wdog_exit(void)1327 static void __exit ipmi_wdog_exit(void)
1328 {
1329 ipmi_smi_watcher_unregister(&smi_watcher);
1330 ipmi_unregister_watchdog(watchdog_ifnum);
1331
1332 #ifdef HAVE_DIE_NMI
1333 if (nmi_handler_registered)
1334 unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
1335 #endif
1336
1337 unregister_reboot_notifier(&wdog_reboot_notifier);
1338 }
1339 module_exit(ipmi_wdog_exit);
1340 module_init(ipmi_wdog_init);
1341 MODULE_LICENSE("GPL");
1342 MODULE_AUTHOR("Corey Minyard <minyard@mvista.com>");
1343 MODULE_DESCRIPTION("watchdog timer based upon the IPMI interface.");
1344