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, 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 
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, &param_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, &param_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, &param_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);
343 static void msg_free_smi(struct ipmi_smi_msg *msg)
344 {
345 	if (atomic_dec_and_test(&msg_tofree))
346 		complete(&msg_wait);
347 }
348 static void msg_free_recv(struct ipmi_recv_msg *msg)
349 {
350 	if (atomic_dec_and_test(&msg_tofree))
351 		complete(&msg_wait);
352 }
353 static struct ipmi_smi_msg smi_msg = {
354 	.done = msg_free_smi
355 };
356 static struct ipmi_recv_msg recv_msg = {
357 	.done = msg_free_recv
358 };
359 
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 
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 		return rv;
439 
440 	wait_for_completion(&msg_wait);
441 
442 	if ((do_heartbeat == IPMI_SET_TIMEOUT_FORCE_HB)
443 		|| ((send_heartbeat_now)
444 		    && (do_heartbeat == IPMI_SET_TIMEOUT_HB_IF_NECESSARY)))
445 		rv = __ipmi_heartbeat();
446 
447 	return rv;
448 }
449 
450 static int ipmi_set_timeout(int do_heartbeat)
451 {
452 	int rv;
453 
454 	mutex_lock(&ipmi_watchdog_mutex);
455 	rv = _ipmi_set_timeout(do_heartbeat);
456 	mutex_unlock(&ipmi_watchdog_mutex);
457 
458 	return rv;
459 }
460 
461 static atomic_t panic_done_count = ATOMIC_INIT(0);
462 
463 static void panic_smi_free(struct ipmi_smi_msg *msg)
464 {
465 	atomic_dec(&panic_done_count);
466 }
467 static void panic_recv_free(struct ipmi_recv_msg *msg)
468 {
469 	atomic_dec(&panic_done_count);
470 }
471 
472 static struct ipmi_smi_msg panic_halt_heartbeat_smi_msg = {
473 	.done = panic_smi_free
474 };
475 static struct ipmi_recv_msg panic_halt_heartbeat_recv_msg = {
476 	.done = panic_recv_free
477 };
478 
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_inc(&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_dec(&panic_done_count);
511 }
512 
513 static struct ipmi_smi_msg panic_halt_smi_msg = {
514 	.done = panic_smi_free
515 };
516 static struct ipmi_recv_msg panic_halt_recv_msg = {
517 	.done = panic_recv_free
518 };
519 
520 /*
521  * Special call, doesn't claim any locks.  This is only to be called
522  * at panic or halt time, in run-to-completion mode, when the caller
523  * is the only CPU and the only thing that will be going is these IPMI
524  * calls.
525  */
526 static void panic_halt_ipmi_set_timeout(void)
527 {
528 	int send_heartbeat_now;
529 	int rv;
530 
531 	/* Wait for the messages to be free. */
532 	while (atomic_read(&panic_done_count) != 0)
533 		ipmi_poll_interface(watchdog_user);
534 	atomic_inc(&panic_done_count);
535 	rv = __ipmi_set_timeout(&panic_halt_smi_msg,
536 				&panic_halt_recv_msg,
537 				&send_heartbeat_now);
538 	if (rv) {
539 		atomic_dec(&panic_done_count);
540 		pr_warn("Unable to extend the watchdog timeout\n");
541 	} else {
542 		if (send_heartbeat_now)
543 			panic_halt_ipmi_heartbeat();
544 	}
545 	while (atomic_read(&panic_done_count) != 0)
546 		ipmi_poll_interface(watchdog_user);
547 }
548 
549 static int __ipmi_heartbeat(void)
550 {
551 	struct kernel_ipmi_msg msg;
552 	int rv;
553 	struct ipmi_system_interface_addr addr;
554 	int timeout_retries = 0;
555 
556 restart:
557 	/*
558 	 * Don't reset the timer if we have the timer turned off, that
559 	 * re-enables the watchdog.
560 	 */
561 	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
562 		return 0;
563 
564 	atomic_set(&msg_tofree, 2);
565 
566 	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
567 	addr.channel = IPMI_BMC_CHANNEL;
568 	addr.lun = 0;
569 
570 	msg.netfn = 0x06;
571 	msg.cmd = IPMI_WDOG_RESET_TIMER;
572 	msg.data = NULL;
573 	msg.data_len = 0;
574 	rv = ipmi_request_supply_msgs(watchdog_user,
575 				      (struct ipmi_addr *) &addr,
576 				      0,
577 				      &msg,
578 				      NULL,
579 				      &smi_msg,
580 				      &recv_msg,
581 				      1);
582 	if (rv) {
583 		pr_warn("heartbeat send failure: %d\n", rv);
584 		return rv;
585 	}
586 
587 	/* Wait for the heartbeat to be sent. */
588 	wait_for_completion(&msg_wait);
589 
590 	if (recv_msg.msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)  {
591 		timeout_retries++;
592 		if (timeout_retries > 3) {
593 			pr_err("Unable to restore the IPMI watchdog's settings, giving up\n");
594 			rv = -EIO;
595 			goto out;
596 		}
597 
598 		/*
599 		 * The timer was not initialized, that means the BMC was
600 		 * probably reset and lost the watchdog information.  Attempt
601 		 * to restore the timer's info.  Note that we still hold
602 		 * the heartbeat lock, to keep a heartbeat from happening
603 		 * in this process, so must say no heartbeat to avoid a
604 		 * deadlock on this mutex
605 		 */
606 		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
607 		if (rv) {
608 			pr_err("Unable to send the command to set the watchdog's settings, giving up\n");
609 			goto out;
610 		}
611 
612 		/* Might need a heartbeat send, go ahead and do it. */
613 		goto restart;
614 	} else if (recv_msg.msg.data[0] != 0) {
615 		/*
616 		 * Got an error in the heartbeat response.  It was already
617 		 * reported in ipmi_wdog_msg_handler, but we should return
618 		 * an error here.
619 		 */
620 		rv = -EINVAL;
621 	}
622 
623 out:
624 	return rv;
625 }
626 
627 static int _ipmi_heartbeat(void)
628 {
629 	int rv;
630 
631 	if (!watchdog_user)
632 		return -ENODEV;
633 
634 	if (ipmi_start_timer_on_heartbeat) {
635 		ipmi_start_timer_on_heartbeat = 0;
636 		ipmi_watchdog_state = action_val;
637 		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
638 	} else if (atomic_cmpxchg(&pretimeout_since_last_heartbeat, 1, 0)) {
639 		/*
640 		 * A pretimeout occurred, make sure we set the timeout.
641 		 * We don't want to set the action, though, we want to
642 		 * leave that alone (thus it can't be combined with the
643 		 * above operation.
644 		 */
645 		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
646 	} else {
647 		rv = __ipmi_heartbeat();
648 	}
649 
650 	return rv;
651 }
652 
653 static int ipmi_heartbeat(void)
654 {
655 	int rv;
656 
657 	mutex_lock(&ipmi_watchdog_mutex);
658 	rv = _ipmi_heartbeat();
659 	mutex_unlock(&ipmi_watchdog_mutex);
660 
661 	return rv;
662 }
663 
664 static struct watchdog_info ident = {
665 	.options	= 0,	/* WDIOF_SETTIMEOUT, */
666 	.firmware_version = 1,
667 	.identity	= "IPMI"
668 };
669 
670 static int ipmi_ioctl(struct file *file,
671 		      unsigned int cmd, unsigned long arg)
672 {
673 	void __user *argp = (void __user *)arg;
674 	int i;
675 	int val;
676 
677 	switch (cmd) {
678 	case WDIOC_GETSUPPORT:
679 		i = copy_to_user(argp, &ident, sizeof(ident));
680 		return i ? -EFAULT : 0;
681 
682 	case WDIOC_SETTIMEOUT:
683 		i = copy_from_user(&val, argp, sizeof(int));
684 		if (i)
685 			return -EFAULT;
686 		timeout = val;
687 		return _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
688 
689 	case WDIOC_GETTIMEOUT:
690 		i = copy_to_user(argp, &timeout, sizeof(timeout));
691 		if (i)
692 			return -EFAULT;
693 		return 0;
694 
695 	case WDIOC_SETPRETIMEOUT:
696 		i = copy_from_user(&val, argp, sizeof(int));
697 		if (i)
698 			return -EFAULT;
699 		pretimeout = val;
700 		return _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
701 
702 	case WDIOC_GETPRETIMEOUT:
703 		i = copy_to_user(argp, &pretimeout, sizeof(pretimeout));
704 		if (i)
705 			return -EFAULT;
706 		return 0;
707 
708 	case WDIOC_KEEPALIVE:
709 		return _ipmi_heartbeat();
710 
711 	case WDIOC_SETOPTIONS:
712 		i = copy_from_user(&val, argp, sizeof(int));
713 		if (i)
714 			return -EFAULT;
715 		if (val & WDIOS_DISABLECARD) {
716 			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
717 			_ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
718 			ipmi_start_timer_on_heartbeat = 0;
719 		}
720 
721 		if (val & WDIOS_ENABLECARD) {
722 			ipmi_watchdog_state = action_val;
723 			_ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
724 		}
725 		return 0;
726 
727 	case WDIOC_GETSTATUS:
728 		val = 0;
729 		i = copy_to_user(argp, &val, sizeof(val));
730 		if (i)
731 			return -EFAULT;
732 		return 0;
733 
734 	default:
735 		return -ENOIOCTLCMD;
736 	}
737 }
738 
739 static long ipmi_unlocked_ioctl(struct file *file,
740 				unsigned int cmd,
741 				unsigned long arg)
742 {
743 	int ret;
744 
745 	mutex_lock(&ipmi_watchdog_mutex);
746 	ret = ipmi_ioctl(file, cmd, arg);
747 	mutex_unlock(&ipmi_watchdog_mutex);
748 
749 	return ret;
750 }
751 
752 static ssize_t ipmi_write(struct file *file,
753 			  const char  __user *buf,
754 			  size_t      len,
755 			  loff_t      *ppos)
756 {
757 	int rv;
758 
759 	if (len) {
760 		if (!nowayout) {
761 			size_t i;
762 
763 			/* In case it was set long ago */
764 			expect_close = 0;
765 
766 			for (i = 0; i != len; i++) {
767 				char c;
768 
769 				if (get_user(c, buf + i))
770 					return -EFAULT;
771 				if (c == 'V')
772 					expect_close = 42;
773 			}
774 		}
775 		rv = ipmi_heartbeat();
776 		if (rv)
777 			return rv;
778 	}
779 	return len;
780 }
781 
782 static ssize_t ipmi_read(struct file *file,
783 			 char        __user *buf,
784 			 size_t      count,
785 			 loff_t      *ppos)
786 {
787 	int          rv = 0;
788 	wait_queue_entry_t wait;
789 
790 	if (count <= 0)
791 		return 0;
792 
793 	/*
794 	 * Reading returns if the pretimeout has gone off, and it only does
795 	 * it once per pretimeout.
796 	 */
797 	spin_lock_irq(&ipmi_read_lock);
798 	if (!data_to_read) {
799 		if (file->f_flags & O_NONBLOCK) {
800 			rv = -EAGAIN;
801 			goto out;
802 		}
803 
804 		init_waitqueue_entry(&wait, current);
805 		add_wait_queue(&read_q, &wait);
806 		while (!data_to_read) {
807 			set_current_state(TASK_INTERRUPTIBLE);
808 			spin_unlock_irq(&ipmi_read_lock);
809 			schedule();
810 			spin_lock_irq(&ipmi_read_lock);
811 		}
812 		remove_wait_queue(&read_q, &wait);
813 
814 		if (signal_pending(current)) {
815 			rv = -ERESTARTSYS;
816 			goto out;
817 		}
818 	}
819 	data_to_read = 0;
820 
821  out:
822 	spin_unlock_irq(&ipmi_read_lock);
823 
824 	if (rv == 0) {
825 		if (copy_to_user(buf, &data_to_read, 1))
826 			rv = -EFAULT;
827 		else
828 			rv = 1;
829 	}
830 
831 	return rv;
832 }
833 
834 static int ipmi_open(struct inode *ino, struct file *filep)
835 {
836 	switch (iminor(ino)) {
837 	case WATCHDOG_MINOR:
838 		if (test_and_set_bit(0, &ipmi_wdog_open))
839 			return -EBUSY;
840 
841 
842 		/*
843 		 * Don't start the timer now, let it start on the
844 		 * first heartbeat.
845 		 */
846 		ipmi_start_timer_on_heartbeat = 1;
847 		return stream_open(ino, filep);
848 
849 	default:
850 		return (-ENODEV);
851 	}
852 }
853 
854 static __poll_t ipmi_poll(struct file *file, poll_table *wait)
855 {
856 	__poll_t mask = 0;
857 
858 	poll_wait(file, &read_q, wait);
859 
860 	spin_lock_irq(&ipmi_read_lock);
861 	if (data_to_read)
862 		mask |= (EPOLLIN | EPOLLRDNORM);
863 	spin_unlock_irq(&ipmi_read_lock);
864 
865 	return mask;
866 }
867 
868 static int ipmi_fasync(int fd, struct file *file, int on)
869 {
870 	int result;
871 
872 	result = fasync_helper(fd, file, on, &fasync_q);
873 
874 	return (result);
875 }
876 
877 static int ipmi_close(struct inode *ino, struct file *filep)
878 {
879 	if (iminor(ino) == WATCHDOG_MINOR) {
880 		if (expect_close == 42) {
881 			mutex_lock(&ipmi_watchdog_mutex);
882 			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
883 			_ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
884 			mutex_unlock(&ipmi_watchdog_mutex);
885 		} else {
886 			pr_crit("Unexpected close, not stopping watchdog!\n");
887 			ipmi_heartbeat();
888 		}
889 		clear_bit(0, &ipmi_wdog_open);
890 	}
891 
892 	expect_close = 0;
893 
894 	return 0;
895 }
896 
897 static const struct file_operations ipmi_wdog_fops = {
898 	.owner   = THIS_MODULE,
899 	.read    = ipmi_read,
900 	.poll    = ipmi_poll,
901 	.write   = ipmi_write,
902 	.unlocked_ioctl = ipmi_unlocked_ioctl,
903 	.compat_ioctl	= compat_ptr_ioctl,
904 	.open    = ipmi_open,
905 	.release = ipmi_close,
906 	.fasync  = ipmi_fasync,
907 	.llseek  = no_llseek,
908 };
909 
910 static struct miscdevice ipmi_wdog_miscdev = {
911 	.minor		= WATCHDOG_MINOR,
912 	.name		= "watchdog",
913 	.fops		= &ipmi_wdog_fops
914 };
915 
916 static void ipmi_wdog_msg_handler(struct ipmi_recv_msg *msg,
917 				  void                 *handler_data)
918 {
919 	if (msg->msg.cmd == IPMI_WDOG_RESET_TIMER &&
920 			msg->msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)
921 		pr_info("response: The IPMI controller appears to have been reset, will attempt to reinitialize the watchdog timer\n");
922 	else if (msg->msg.data[0] != 0)
923 		pr_err("response: Error %x on cmd %x\n",
924 		       msg->msg.data[0],
925 		       msg->msg.cmd);
926 
927 	ipmi_free_recv_msg(msg);
928 }
929 
930 static void ipmi_wdog_pretimeout_handler(void *handler_data)
931 {
932 	if (preaction_val != WDOG_PRETIMEOUT_NONE) {
933 		if (preop_val == WDOG_PREOP_PANIC) {
934 			if (atomic_inc_and_test(&preop_panic_excl))
935 				panic("Watchdog pre-timeout");
936 		} else if (preop_val == WDOG_PREOP_GIVE_DATA) {
937 			unsigned long flags;
938 
939 			spin_lock_irqsave(&ipmi_read_lock, flags);
940 			data_to_read = 1;
941 			wake_up_interruptible(&read_q);
942 			kill_fasync(&fasync_q, SIGIO, POLL_IN);
943 			spin_unlock_irqrestore(&ipmi_read_lock, flags);
944 		}
945 	}
946 
947 	/*
948 	 * On some machines, the heartbeat will give an error and not
949 	 * work unless we re-enable the timer.  So do so.
950 	 */
951 	atomic_set(&pretimeout_since_last_heartbeat, 1);
952 }
953 
954 static void ipmi_wdog_panic_handler(void *user_data)
955 {
956 	static int panic_event_handled;
957 
958 	/*
959 	 * On a panic, if we have a panic timeout, make sure to extend
960 	 * the watchdog timer to a reasonable value to complete the
961 	 * panic, if the watchdog timer is running.  Plus the
962 	 * pretimeout is meaningless at panic time.
963 	 */
964 	if (watchdog_user && !panic_event_handled &&
965 	    ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
966 		/* Make sure we do this only once. */
967 		panic_event_handled = 1;
968 
969 		timeout = panic_wdt_timeout;
970 		pretimeout = 0;
971 		panic_halt_ipmi_set_timeout();
972 	}
973 }
974 
975 static const struct ipmi_user_hndl ipmi_hndlrs = {
976 	.ipmi_recv_hndl           = ipmi_wdog_msg_handler,
977 	.ipmi_watchdog_pretimeout = ipmi_wdog_pretimeout_handler,
978 	.ipmi_panic_handler       = ipmi_wdog_panic_handler
979 };
980 
981 static void ipmi_register_watchdog(int ipmi_intf)
982 {
983 	int rv = -EBUSY;
984 
985 	if (watchdog_user)
986 		goto out;
987 
988 	if ((ifnum_to_use >= 0) && (ifnum_to_use != ipmi_intf))
989 		goto out;
990 
991 	watchdog_ifnum = ipmi_intf;
992 
993 	rv = ipmi_create_user(ipmi_intf, &ipmi_hndlrs, NULL, &watchdog_user);
994 	if (rv < 0) {
995 		pr_crit("Unable to register with ipmi\n");
996 		goto out;
997 	}
998 
999 	rv = ipmi_get_version(watchdog_user,
1000 			      &ipmi_version_major,
1001 			      &ipmi_version_minor);
1002 	if (rv) {
1003 		pr_warn("Unable to get IPMI version, assuming 1.0\n");
1004 		ipmi_version_major = 1;
1005 		ipmi_version_minor = 0;
1006 	}
1007 
1008 	rv = misc_register(&ipmi_wdog_miscdev);
1009 	if (rv < 0) {
1010 		ipmi_destroy_user(watchdog_user);
1011 		watchdog_user = NULL;
1012 		pr_crit("Unable to register misc device\n");
1013 	}
1014 
1015 #ifdef HAVE_DIE_NMI
1016 	if (nmi_handler_registered) {
1017 		int old_pretimeout = pretimeout;
1018 		int old_timeout = timeout;
1019 		int old_preop_val = preop_val;
1020 
1021 		/*
1022 		 * Set the pretimeout to go off in a second and give
1023 		 * ourselves plenty of time to stop the timer.
1024 		 */
1025 		ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
1026 		preop_val = WDOG_PREOP_NONE; /* Make sure nothing happens */
1027 		pretimeout = 99;
1028 		timeout = 100;
1029 
1030 		testing_nmi = 1;
1031 
1032 		rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
1033 		if (rv) {
1034 			pr_warn("Error starting timer to test NMI: 0x%x.  The NMI pretimeout will likely not work\n",
1035 				rv);
1036 			rv = 0;
1037 			goto out_restore;
1038 		}
1039 
1040 		msleep(1500);
1041 
1042 		if (testing_nmi != 2) {
1043 			pr_warn("IPMI NMI didn't seem to occur.  The NMI pretimeout will likely not work\n");
1044 		}
1045  out_restore:
1046 		testing_nmi = 0;
1047 		preop_val = old_preop_val;
1048 		pretimeout = old_pretimeout;
1049 		timeout = old_timeout;
1050 	}
1051 #endif
1052 
1053  out:
1054 	if ((start_now) && (rv == 0)) {
1055 		/* Run from startup, so start the timer now. */
1056 		start_now = 0; /* Disable this function after first startup. */
1057 		ipmi_watchdog_state = action_val;
1058 		ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
1059 		pr_info("Starting now!\n");
1060 	} else {
1061 		/* Stop the timer now. */
1062 		ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
1063 		ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
1064 	}
1065 }
1066 
1067 static void ipmi_unregister_watchdog(int ipmi_intf)
1068 {
1069 	int rv;
1070 	struct ipmi_user *loc_user = watchdog_user;
1071 
1072 	if (!loc_user)
1073 		return;
1074 
1075 	if (watchdog_ifnum != ipmi_intf)
1076 		return;
1077 
1078 	/* Make sure no one can call us any more. */
1079 	misc_deregister(&ipmi_wdog_miscdev);
1080 
1081 	watchdog_user = NULL;
1082 
1083 	/*
1084 	 * Wait to make sure the message makes it out.  The lower layer has
1085 	 * pointers to our buffers, we want to make sure they are done before
1086 	 * we release our memory.
1087 	 */
1088 	while (atomic_read(&msg_tofree))
1089 		msg_free_smi(NULL);
1090 
1091 	mutex_lock(&ipmi_watchdog_mutex);
1092 
1093 	/* Disconnect from IPMI. */
1094 	rv = ipmi_destroy_user(loc_user);
1095 	if (rv)
1096 		pr_warn("error unlinking from IPMI: %d\n",  rv);
1097 
1098 	/* If it comes back, restart it properly. */
1099 	ipmi_start_timer_on_heartbeat = 1;
1100 
1101 	mutex_unlock(&ipmi_watchdog_mutex);
1102 }
1103 
1104 #ifdef HAVE_DIE_NMI
1105 static int
1106 ipmi_nmi(unsigned int val, struct pt_regs *regs)
1107 {
1108 	/*
1109 	 * If we get here, it's an NMI that's not a memory or I/O
1110 	 * error.  We can't truly tell if it's from IPMI or not
1111 	 * without sending a message, and sending a message is almost
1112 	 * impossible because of locking.
1113 	 */
1114 
1115 	if (testing_nmi) {
1116 		testing_nmi = 2;
1117 		return NMI_HANDLED;
1118 	}
1119 
1120 	/* If we are not expecting a timeout, ignore it. */
1121 	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
1122 		return NMI_DONE;
1123 
1124 	if (preaction_val != WDOG_PRETIMEOUT_NMI)
1125 		return NMI_DONE;
1126 
1127 	/*
1128 	 * If no one else handled the NMI, we assume it was the IPMI
1129 	 * watchdog.
1130 	 */
1131 	if (preop_val == WDOG_PREOP_PANIC) {
1132 		/* On some machines, the heartbeat will give
1133 		   an error and not work unless we re-enable
1134 		   the timer.   So do so. */
1135 		atomic_set(&pretimeout_since_last_heartbeat, 1);
1136 		if (atomic_inc_and_test(&preop_panic_excl))
1137 			nmi_panic(regs, "pre-timeout");
1138 	}
1139 
1140 	return NMI_HANDLED;
1141 }
1142 #endif
1143 
1144 static int wdog_reboot_handler(struct notifier_block *this,
1145 			       unsigned long         code,
1146 			       void                  *unused)
1147 {
1148 	static int reboot_event_handled;
1149 
1150 	if ((watchdog_user) && (!reboot_event_handled)) {
1151 		/* Make sure we only do this once. */
1152 		reboot_event_handled = 1;
1153 
1154 		if (code == SYS_POWER_OFF || code == SYS_HALT) {
1155 			/* Disable the WDT if we are shutting down. */
1156 			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
1157 			ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
1158 		} else if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
1159 			/* Set a long timer to let the reboot happen or
1160 			   reset if it hangs, but only if the watchdog
1161 			   timer was already running. */
1162 			if (timeout < 120)
1163 				timeout = 120;
1164 			pretimeout = 0;
1165 			ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
1166 			ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
1167 		}
1168 	}
1169 	return NOTIFY_OK;
1170 }
1171 
1172 static struct notifier_block wdog_reboot_notifier = {
1173 	.notifier_call	= wdog_reboot_handler,
1174 	.next		= NULL,
1175 	.priority	= 0
1176 };
1177 
1178 static void ipmi_new_smi(int if_num, struct device *device)
1179 {
1180 	ipmi_register_watchdog(if_num);
1181 }
1182 
1183 static void ipmi_smi_gone(int if_num)
1184 {
1185 	ipmi_unregister_watchdog(if_num);
1186 }
1187 
1188 static struct ipmi_smi_watcher smi_watcher = {
1189 	.owner    = THIS_MODULE,
1190 	.new_smi  = ipmi_new_smi,
1191 	.smi_gone = ipmi_smi_gone
1192 };
1193 
1194 static int action_op(const char *inval, char *outval)
1195 {
1196 	if (outval)
1197 		strcpy(outval, action);
1198 
1199 	if (!inval)
1200 		return 0;
1201 
1202 	if (strcmp(inval, "reset") == 0)
1203 		action_val = WDOG_TIMEOUT_RESET;
1204 	else if (strcmp(inval, "none") == 0)
1205 		action_val = WDOG_TIMEOUT_NONE;
1206 	else if (strcmp(inval, "power_cycle") == 0)
1207 		action_val = WDOG_TIMEOUT_POWER_CYCLE;
1208 	else if (strcmp(inval, "power_off") == 0)
1209 		action_val = WDOG_TIMEOUT_POWER_DOWN;
1210 	else
1211 		return -EINVAL;
1212 	strcpy(action, inval);
1213 	return 0;
1214 }
1215 
1216 static int preaction_op(const char *inval, char *outval)
1217 {
1218 	if (outval)
1219 		strcpy(outval, preaction);
1220 
1221 	if (!inval)
1222 		return 0;
1223 
1224 	if (strcmp(inval, "pre_none") == 0)
1225 		preaction_val = WDOG_PRETIMEOUT_NONE;
1226 	else if (strcmp(inval, "pre_smi") == 0)
1227 		preaction_val = WDOG_PRETIMEOUT_SMI;
1228 #ifdef HAVE_DIE_NMI
1229 	else if (strcmp(inval, "pre_nmi") == 0)
1230 		preaction_val = WDOG_PRETIMEOUT_NMI;
1231 #endif
1232 	else if (strcmp(inval, "pre_int") == 0)
1233 		preaction_val = WDOG_PRETIMEOUT_MSG_INT;
1234 	else
1235 		return -EINVAL;
1236 	strcpy(preaction, inval);
1237 	return 0;
1238 }
1239 
1240 static int preop_op(const char *inval, char *outval)
1241 {
1242 	if (outval)
1243 		strcpy(outval, preop);
1244 
1245 	if (!inval)
1246 		return 0;
1247 
1248 	if (strcmp(inval, "preop_none") == 0)
1249 		preop_val = WDOG_PREOP_NONE;
1250 	else if (strcmp(inval, "preop_panic") == 0)
1251 		preop_val = WDOG_PREOP_PANIC;
1252 	else if (strcmp(inval, "preop_give_data") == 0)
1253 		preop_val = WDOG_PREOP_GIVE_DATA;
1254 	else
1255 		return -EINVAL;
1256 	strcpy(preop, inval);
1257 	return 0;
1258 }
1259 
1260 static void check_parms(void)
1261 {
1262 #ifdef HAVE_DIE_NMI
1263 	int do_nmi = 0;
1264 	int rv;
1265 
1266 	if (preaction_val == WDOG_PRETIMEOUT_NMI) {
1267 		do_nmi = 1;
1268 		if (preop_val == WDOG_PREOP_GIVE_DATA) {
1269 			pr_warn("Pretimeout op is to give data but NMI pretimeout is enabled, setting pretimeout op to none\n");
1270 			preop_op("preop_none", NULL);
1271 			do_nmi = 0;
1272 		}
1273 	}
1274 	if (do_nmi && !nmi_handler_registered) {
1275 		rv = register_nmi_handler(NMI_UNKNOWN, ipmi_nmi, 0,
1276 						"ipmi");
1277 		if (rv) {
1278 			pr_warn("Can't register nmi handler\n");
1279 			return;
1280 		} else
1281 			nmi_handler_registered = 1;
1282 	} else if (!do_nmi && nmi_handler_registered) {
1283 		unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
1284 		nmi_handler_registered = 0;
1285 	}
1286 #endif
1287 }
1288 
1289 static int __init ipmi_wdog_init(void)
1290 {
1291 	int rv;
1292 
1293 	if (action_op(action, NULL)) {
1294 		action_op("reset", NULL);
1295 		pr_info("Unknown action '%s', defaulting to reset\n", action);
1296 	}
1297 
1298 	if (preaction_op(preaction, NULL)) {
1299 		preaction_op("pre_none", NULL);
1300 		pr_info("Unknown preaction '%s', defaulting to none\n",
1301 			preaction);
1302 	}
1303 
1304 	if (preop_op(preop, NULL)) {
1305 		preop_op("preop_none", NULL);
1306 		pr_info("Unknown preop '%s', defaulting to none\n", preop);
1307 	}
1308 
1309 	check_parms();
1310 
1311 	register_reboot_notifier(&wdog_reboot_notifier);
1312 
1313 	rv = ipmi_smi_watcher_register(&smi_watcher);
1314 	if (rv) {
1315 #ifdef HAVE_DIE_NMI
1316 		if (nmi_handler_registered)
1317 			unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
1318 #endif
1319 		unregister_reboot_notifier(&wdog_reboot_notifier);
1320 		pr_warn("can't register smi watcher\n");
1321 		return rv;
1322 	}
1323 
1324 	pr_info("driver initialized\n");
1325 
1326 	return 0;
1327 }
1328 
1329 static void __exit ipmi_wdog_exit(void)
1330 {
1331 	ipmi_smi_watcher_unregister(&smi_watcher);
1332 	ipmi_unregister_watchdog(watchdog_ifnum);
1333 
1334 #ifdef HAVE_DIE_NMI
1335 	if (nmi_handler_registered)
1336 		unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
1337 #endif
1338 
1339 	unregister_reboot_notifier(&wdog_reboot_notifier);
1340 }
1341 module_exit(ipmi_wdog_exit);
1342 module_init(ipmi_wdog_init);
1343 MODULE_LICENSE("GPL");
1344 MODULE_AUTHOR("Corey Minyard <minyard@mvista.com>");
1345 MODULE_DESCRIPTION("watchdog timer based upon the IPMI interface.");
1346