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_version_major > 1)
375 	    || ((ipmi_version_major == 1) && (ipmi_version_minor >= 5))) {
376 		/* This is an IPMI 1.5-only feature. */
377 		data[0] |= WDOG_DONT_STOP_ON_SET;
378 	} else if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
379 		/*
380 		 * In ipmi 1.0, setting the timer stops the watchdog, we
381 		 * need to start it back up again.
382 		 */
383 		hbnow = 1;
384 	}
385 
386 	data[1] = 0;
387 	WDOG_SET_TIMEOUT_ACT(data[1], ipmi_watchdog_state);
388 	if ((pretimeout > 0) && (ipmi_watchdog_state != WDOG_TIMEOUT_NONE)) {
389 	    WDOG_SET_PRETIMEOUT_ACT(data[1], preaction_val);
390 	    data[2] = pretimeout;
391 	} else {
392 	    WDOG_SET_PRETIMEOUT_ACT(data[1], WDOG_PRETIMEOUT_NONE);
393 	    data[2] = 0; /* No pretimeout. */
394 	}
395 	data[3] = 0;
396 	WDOG_SET_TIMEOUT(data[4], data[5], timeout);
397 
398 	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
399 	addr.channel = IPMI_BMC_CHANNEL;
400 	addr.lun = 0;
401 
402 	msg.netfn = 0x06;
403 	msg.cmd = IPMI_WDOG_SET_TIMER;
404 	msg.data = data;
405 	msg.data_len = sizeof(data);
406 	rv = ipmi_request_supply_msgs(watchdog_user,
407 				      (struct ipmi_addr *) &addr,
408 				      0,
409 				      &msg,
410 				      NULL,
411 				      smi_msg,
412 				      recv_msg,
413 				      1);
414 	if (rv)
415 		pr_warn("set timeout error: %d\n", rv);
416 	else if (send_heartbeat_now)
417 		*send_heartbeat_now = hbnow;
418 
419 	return rv;
420 }
421 
422 static int _ipmi_set_timeout(int do_heartbeat)
423 {
424 	int send_heartbeat_now;
425 	int rv;
426 
427 	if (!watchdog_user)
428 		return -ENODEV;
429 
430 	atomic_set(&msg_tofree, 2);
431 
432 	rv = __ipmi_set_timeout(&smi_msg,
433 				&recv_msg,
434 				&send_heartbeat_now);
435 	if (rv)
436 		return rv;
437 
438 	wait_for_completion(&msg_wait);
439 
440 	if ((do_heartbeat == IPMI_SET_TIMEOUT_FORCE_HB)
441 		|| ((send_heartbeat_now)
442 		    && (do_heartbeat == IPMI_SET_TIMEOUT_HB_IF_NECESSARY)))
443 		rv = __ipmi_heartbeat();
444 
445 	return rv;
446 }
447 
448 static int ipmi_set_timeout(int do_heartbeat)
449 {
450 	int rv;
451 
452 	mutex_lock(&ipmi_watchdog_mutex);
453 	rv = _ipmi_set_timeout(do_heartbeat);
454 	mutex_unlock(&ipmi_watchdog_mutex);
455 
456 	return rv;
457 }
458 
459 static atomic_t panic_done_count = ATOMIC_INIT(0);
460 
461 static void panic_smi_free(struct ipmi_smi_msg *msg)
462 {
463 	atomic_dec(&panic_done_count);
464 }
465 static void panic_recv_free(struct ipmi_recv_msg *msg)
466 {
467 	atomic_dec(&panic_done_count);
468 }
469 
470 static struct ipmi_smi_msg panic_halt_heartbeat_smi_msg = {
471 	.done = panic_smi_free
472 };
473 static struct ipmi_recv_msg panic_halt_heartbeat_recv_msg = {
474 	.done = panic_recv_free
475 };
476 
477 static void panic_halt_ipmi_heartbeat(void)
478 {
479 	struct kernel_ipmi_msg             msg;
480 	struct ipmi_system_interface_addr addr;
481 	int rv;
482 
483 	/*
484 	 * Don't reset the timer if we have the timer turned off, that
485 	 * re-enables the watchdog.
486 	 */
487 	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
488 		return;
489 
490 	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
491 	addr.channel = IPMI_BMC_CHANNEL;
492 	addr.lun = 0;
493 
494 	msg.netfn = 0x06;
495 	msg.cmd = IPMI_WDOG_RESET_TIMER;
496 	msg.data = NULL;
497 	msg.data_len = 0;
498 	atomic_inc(&panic_done_count);
499 	rv = ipmi_request_supply_msgs(watchdog_user,
500 				      (struct ipmi_addr *) &addr,
501 				      0,
502 				      &msg,
503 				      NULL,
504 				      &panic_halt_heartbeat_smi_msg,
505 				      &panic_halt_heartbeat_recv_msg,
506 				      1);
507 	if (rv)
508 		atomic_dec(&panic_done_count);
509 }
510 
511 static struct ipmi_smi_msg panic_halt_smi_msg = {
512 	.done = panic_smi_free
513 };
514 static struct ipmi_recv_msg panic_halt_recv_msg = {
515 	.done = panic_recv_free
516 };
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  */
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_inc(&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_dec(&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 
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 		pr_warn("heartbeat send failure: %d\n", rv);
582 		return rv;
583 	}
584 
585 	/* Wait for the heartbeat to be sent. */
586 	wait_for_completion(&msg_wait);
587 
588 	if (recv_msg.msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)  {
589 		timeout_retries++;
590 		if (timeout_retries > 3) {
591 			pr_err("Unable to restore the IPMI watchdog's settings, giving up\n");
592 			rv = -EIO;
593 			goto out;
594 		}
595 
596 		/*
597 		 * The timer was not initialized, that means the BMC was
598 		 * probably reset and lost the watchdog information.  Attempt
599 		 * to restore the timer's info.  Note that we still hold
600 		 * the heartbeat lock, to keep a heartbeat from happening
601 		 * in this process, so must say no heartbeat to avoid a
602 		 * deadlock on this mutex
603 		 */
604 		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
605 		if (rv) {
606 			pr_err("Unable to send the command to set the watchdog's settings, giving up\n");
607 			goto out;
608 		}
609 
610 		/* Might need a heartbeat send, go ahead and do it. */
611 		goto restart;
612 	} else if (recv_msg.msg.data[0] != 0) {
613 		/*
614 		 * Got an error in the heartbeat response.  It was already
615 		 * reported in ipmi_wdog_msg_handler, but we should return
616 		 * an error here.
617 		 */
618 		rv = -EINVAL;
619 	}
620 
621 out:
622 	return rv;
623 }
624 
625 static int _ipmi_heartbeat(void)
626 {
627 	int rv;
628 
629 	if (!watchdog_user)
630 		return -ENODEV;
631 
632 	if (ipmi_start_timer_on_heartbeat) {
633 		ipmi_start_timer_on_heartbeat = 0;
634 		ipmi_watchdog_state = action_val;
635 		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
636 	} else if (atomic_cmpxchg(&pretimeout_since_last_heartbeat, 1, 0)) {
637 		/*
638 		 * A pretimeout occurred, make sure we set the timeout.
639 		 * We don't want to set the action, though, we want to
640 		 * leave that alone (thus it can't be combined with the
641 		 * above operation.
642 		 */
643 		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
644 	} else {
645 		rv = __ipmi_heartbeat();
646 	}
647 
648 	return rv;
649 }
650 
651 static int ipmi_heartbeat(void)
652 {
653 	int rv;
654 
655 	mutex_lock(&ipmi_watchdog_mutex);
656 	rv = _ipmi_heartbeat();
657 	mutex_unlock(&ipmi_watchdog_mutex);
658 
659 	return rv;
660 }
661 
662 static struct watchdog_info ident = {
663 	.options	= 0,	/* WDIOF_SETTIMEOUT, */
664 	.firmware_version = 1,
665 	.identity	= "IPMI"
666 };
667 
668 static int ipmi_ioctl(struct file *file,
669 		      unsigned int cmd, unsigned long arg)
670 {
671 	void __user *argp = (void __user *)arg;
672 	int i;
673 	int val;
674 
675 	switch (cmd) {
676 	case WDIOC_GETSUPPORT:
677 		i = copy_to_user(argp, &ident, sizeof(ident));
678 		return i ? -EFAULT : 0;
679 
680 	case WDIOC_SETTIMEOUT:
681 		i = copy_from_user(&val, argp, sizeof(int));
682 		if (i)
683 			return -EFAULT;
684 		timeout = val;
685 		return _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
686 
687 	case WDIOC_GETTIMEOUT:
688 		i = copy_to_user(argp, &timeout, sizeof(timeout));
689 		if (i)
690 			return -EFAULT;
691 		return 0;
692 
693 	case WDIOC_SETPRETIMEOUT:
694 		i = copy_from_user(&val, argp, sizeof(int));
695 		if (i)
696 			return -EFAULT;
697 		pretimeout = val;
698 		return _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
699 
700 	case WDIOC_GETPRETIMEOUT:
701 		i = copy_to_user(argp, &pretimeout, sizeof(pretimeout));
702 		if (i)
703 			return -EFAULT;
704 		return 0;
705 
706 	case WDIOC_KEEPALIVE:
707 		return _ipmi_heartbeat();
708 
709 	case WDIOC_SETOPTIONS:
710 		i = copy_from_user(&val, argp, sizeof(int));
711 		if (i)
712 			return -EFAULT;
713 		if (val & WDIOS_DISABLECARD) {
714 			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
715 			_ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
716 			ipmi_start_timer_on_heartbeat = 0;
717 		}
718 
719 		if (val & WDIOS_ENABLECARD) {
720 			ipmi_watchdog_state = action_val;
721 			_ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
722 		}
723 		return 0;
724 
725 	case WDIOC_GETSTATUS:
726 		val = 0;
727 		i = copy_to_user(argp, &val, sizeof(val));
728 		if (i)
729 			return -EFAULT;
730 		return 0;
731 
732 	default:
733 		return -ENOIOCTLCMD;
734 	}
735 }
736 
737 static long ipmi_unlocked_ioctl(struct file *file,
738 				unsigned int cmd,
739 				unsigned long arg)
740 {
741 	int ret;
742 
743 	mutex_lock(&ipmi_watchdog_mutex);
744 	ret = ipmi_ioctl(file, cmd, arg);
745 	mutex_unlock(&ipmi_watchdog_mutex);
746 
747 	return ret;
748 }
749 
750 static ssize_t ipmi_write(struct file *file,
751 			  const char  __user *buf,
752 			  size_t      len,
753 			  loff_t      *ppos)
754 {
755 	int rv;
756 
757 	if (len) {
758 		if (!nowayout) {
759 			size_t i;
760 
761 			/* In case it was set long ago */
762 			expect_close = 0;
763 
764 			for (i = 0; i != len; i++) {
765 				char c;
766 
767 				if (get_user(c, buf + i))
768 					return -EFAULT;
769 				if (c == 'V')
770 					expect_close = 42;
771 			}
772 		}
773 		rv = ipmi_heartbeat();
774 		if (rv)
775 			return rv;
776 	}
777 	return len;
778 }
779 
780 static ssize_t ipmi_read(struct file *file,
781 			 char        __user *buf,
782 			 size_t      count,
783 			 loff_t      *ppos)
784 {
785 	int          rv = 0;
786 	wait_queue_entry_t wait;
787 
788 	if (count <= 0)
789 		return 0;
790 
791 	/*
792 	 * Reading returns if the pretimeout has gone off, and it only does
793 	 * it once per pretimeout.
794 	 */
795 	spin_lock_irq(&ipmi_read_lock);
796 	if (!data_to_read) {
797 		if (file->f_flags & O_NONBLOCK) {
798 			rv = -EAGAIN;
799 			goto out;
800 		}
801 
802 		init_waitqueue_entry(&wait, current);
803 		add_wait_queue(&read_q, &wait);
804 		while (!data_to_read) {
805 			set_current_state(TASK_INTERRUPTIBLE);
806 			spin_unlock_irq(&ipmi_read_lock);
807 			schedule();
808 			spin_lock_irq(&ipmi_read_lock);
809 		}
810 		remove_wait_queue(&read_q, &wait);
811 
812 		if (signal_pending(current)) {
813 			rv = -ERESTARTSYS;
814 			goto out;
815 		}
816 	}
817 	data_to_read = 0;
818 
819  out:
820 	spin_unlock_irq(&ipmi_read_lock);
821 
822 	if (rv == 0) {
823 		if (copy_to_user(buf, &data_to_read, 1))
824 			rv = -EFAULT;
825 		else
826 			rv = 1;
827 	}
828 
829 	return rv;
830 }
831 
832 static int ipmi_open(struct inode *ino, struct file *filep)
833 {
834 	switch (iminor(ino)) {
835 	case WATCHDOG_MINOR:
836 		if (test_and_set_bit(0, &ipmi_wdog_open))
837 			return -EBUSY;
838 
839 
840 		/*
841 		 * Don't start the timer now, let it start on the
842 		 * first heartbeat.
843 		 */
844 		ipmi_start_timer_on_heartbeat = 1;
845 		return stream_open(ino, filep);
846 
847 	default:
848 		return (-ENODEV);
849 	}
850 }
851 
852 static __poll_t ipmi_poll(struct file *file, poll_table *wait)
853 {
854 	__poll_t mask = 0;
855 
856 	poll_wait(file, &read_q, wait);
857 
858 	spin_lock_irq(&ipmi_read_lock);
859 	if (data_to_read)
860 		mask |= (EPOLLIN | EPOLLRDNORM);
861 	spin_unlock_irq(&ipmi_read_lock);
862 
863 	return mask;
864 }
865 
866 static int ipmi_fasync(int fd, struct file *file, int on)
867 {
868 	int result;
869 
870 	result = fasync_helper(fd, file, on, &fasync_q);
871 
872 	return (result);
873 }
874 
875 static int ipmi_close(struct inode *ino, struct file *filep)
876 {
877 	if (iminor(ino) == WATCHDOG_MINOR) {
878 		if (expect_close == 42) {
879 			mutex_lock(&ipmi_watchdog_mutex);
880 			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
881 			_ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
882 			mutex_unlock(&ipmi_watchdog_mutex);
883 		} else {
884 			pr_crit("Unexpected close, not stopping watchdog!\n");
885 			ipmi_heartbeat();
886 		}
887 		clear_bit(0, &ipmi_wdog_open);
888 	}
889 
890 	expect_close = 0;
891 
892 	return 0;
893 }
894 
895 static const struct file_operations ipmi_wdog_fops = {
896 	.owner   = THIS_MODULE,
897 	.read    = ipmi_read,
898 	.poll    = ipmi_poll,
899 	.write   = ipmi_write,
900 	.unlocked_ioctl = ipmi_unlocked_ioctl,
901 	.compat_ioctl	= compat_ptr_ioctl,
902 	.open    = ipmi_open,
903 	.release = ipmi_close,
904 	.fasync  = ipmi_fasync,
905 	.llseek  = no_llseek,
906 };
907 
908 static struct miscdevice ipmi_wdog_miscdev = {
909 	.minor		= WATCHDOG_MINOR,
910 	.name		= "watchdog",
911 	.fops		= &ipmi_wdog_fops
912 };
913 
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 
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 
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 
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 
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
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 
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 
1176 static void ipmi_new_smi(int if_num, struct device *device)
1177 {
1178 	ipmi_register_watchdog(if_num);
1179 }
1180 
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 
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 
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 
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 
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 
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 
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