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