1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * ipmi_watchdog.c
4  *
5  * A watchdog timer based upon the IPMI interface.
6  *
7  * Author: MontaVista Software, Inc.
8  *         Corey Minyard <minyard@mvista.com>
9  *         source@mvista.com
10  *
11  * Copyright 2002 MontaVista Software Inc.
12  */
13 
14 #define pr_fmt(fmt) "IPMI Watchdog: " fmt
15 
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/ipmi.h>
19 #include <linux/ipmi_smi.h>
20 #include <linux/mutex.h>
21 #include <linux/watchdog.h>
22 #include <linux/miscdevice.h>
23 #include <linux/init.h>
24 #include <linux/completion.h>
25 #include <linux/kdebug.h>
26 #include <linux/kstrtox.h>
27 #include <linux/rwsem.h>
28 #include <linux/errno.h>
29 #include <linux/uaccess.h>
30 #include <linux/notifier.h>
31 #include <linux/nmi.h>
32 #include <linux/reboot.h>
33 #include <linux/wait.h>
34 #include <linux/poll.h>
35 #include <linux/string.h>
36 #include <linux/ctype.h>
37 #include <linux/delay.h>
38 #include <linux/atomic.h>
39 #include <linux/sched/signal.h>
40 
41 #ifdef CONFIG_X86
42 /*
43  * This is ugly, but I've determined that x86 is the only architecture
44  * that can reasonably support the IPMI NMI watchdog timeout at this
45  * time.  If another architecture adds this capability somehow, it
46  * will have to be a somewhat different mechanism and I have no idea
47  * how it will work.  So in the unlikely event that another
48  * architecture supports this, we can figure out a good generic
49  * mechanism for it at that time.
50  */
51 #include <asm/kdebug.h>
52 #include <asm/nmi.h>
53 #define HAVE_DIE_NMI
54 #endif
55 
56 /*
57  * The IPMI command/response information for the watchdog timer.
58  */
59 
60 /* values for byte 1 of the set command, byte 2 of the get response. */
61 #define WDOG_DONT_LOG		(1 << 7)
62 #define WDOG_DONT_STOP_ON_SET	(1 << 6)
63 #define WDOG_SET_TIMER_USE(byte, use) \
64 	byte = ((byte) & 0xf8) | ((use) & 0x7)
65 #define WDOG_GET_TIMER_USE(byte) ((byte) & 0x7)
66 #define WDOG_TIMER_USE_BIOS_FRB2	1
67 #define WDOG_TIMER_USE_BIOS_POST	2
68 #define WDOG_TIMER_USE_OS_LOAD		3
69 #define WDOG_TIMER_USE_SMS_OS		4
70 #define WDOG_TIMER_USE_OEM		5
71 
72 /* values for byte 2 of the set command, byte 3 of the get response. */
73 #define WDOG_SET_PRETIMEOUT_ACT(byte, use) \
74 	byte = ((byte) & 0x8f) | (((use) & 0x7) << 4)
75 #define WDOG_GET_PRETIMEOUT_ACT(byte) (((byte) >> 4) & 0x7)
76 #define WDOG_PRETIMEOUT_NONE		0
77 #define WDOG_PRETIMEOUT_SMI		1
78 #define WDOG_PRETIMEOUT_NMI		2
79 #define WDOG_PRETIMEOUT_MSG_INT		3
80 
81 /* Operations that can be performed on a pretimout. */
82 #define WDOG_PREOP_NONE		0
83 #define WDOG_PREOP_PANIC	1
84 /* Cause data to be available to read.  Doesn't work in NMI mode. */
85 #define WDOG_PREOP_GIVE_DATA	2
86 
87 /* Actions to perform on a full timeout. */
88 #define WDOG_SET_TIMEOUT_ACT(byte, use) \
89 	byte = ((byte) & 0xf8) | ((use) & 0x7)
90 #define WDOG_GET_TIMEOUT_ACT(byte) ((byte) & 0x7)
91 #define WDOG_TIMEOUT_NONE		0
92 #define WDOG_TIMEOUT_RESET		1
93 #define WDOG_TIMEOUT_POWER_DOWN		2
94 #define WDOG_TIMEOUT_POWER_CYCLE	3
95 
96 /*
97  * Byte 3 of the get command, byte 4 of the get response is the
98  * pre-timeout in seconds.
99  */
100 
101 /* Bits for setting byte 4 of the set command, byte 5 of the get response. */
102 #define WDOG_EXPIRE_CLEAR_BIOS_FRB2	(1 << 1)
103 #define WDOG_EXPIRE_CLEAR_BIOS_POST	(1 << 2)
104 #define WDOG_EXPIRE_CLEAR_OS_LOAD	(1 << 3)
105 #define WDOG_EXPIRE_CLEAR_SMS_OS	(1 << 4)
106 #define WDOG_EXPIRE_CLEAR_OEM		(1 << 5)
107 
108 /*
109  * Setting/getting the watchdog timer value.  This is for bytes 5 and
110  * 6 (the timeout time) of the set command, and bytes 6 and 7 (the
111  * timeout time) and 8 and 9 (the current countdown value) of the
112  * response.  The timeout value is given in seconds (in the command it
113  * is 100ms intervals).
114  */
115 #define WDOG_SET_TIMEOUT(byte1, byte2, val) \
116 	(byte1) = (((val) * 10) & 0xff), (byte2) = (((val) * 10) >> 8)
117 #define WDOG_GET_TIMEOUT(byte1, byte2) \
118 	(((byte1) | ((byte2) << 8)) / 10)
119 
120 #define IPMI_WDOG_RESET_TIMER		0x22
121 #define IPMI_WDOG_SET_TIMER		0x24
122 #define IPMI_WDOG_GET_TIMER		0x25
123 
124 #define IPMI_WDOG_TIMER_NOT_INIT_RESP	0x80
125 
126 static DEFINE_MUTEX(ipmi_watchdog_mutex);
127 static bool nowayout = WATCHDOG_NOWAYOUT;
128 
129 static struct ipmi_user *watchdog_user;
130 static int watchdog_ifnum;
131 
132 /* Default the timeout to 10 seconds. */
133 static int timeout = 10;
134 
135 /* The pre-timeout is disabled by default. */
136 static int pretimeout;
137 
138 /* Default timeout to set on panic */
139 static int panic_wdt_timeout = 255;
140 
141 /* Default action is to reset the board on a timeout. */
142 static unsigned char action_val = WDOG_TIMEOUT_RESET;
143 
144 static char action[16] = "reset";
145 
146 static unsigned char preaction_val = WDOG_PRETIMEOUT_NONE;
147 
148 static char preaction[16] = "pre_none";
149 
150 static unsigned char preop_val = WDOG_PREOP_NONE;
151 
152 static char preop[16] = "preop_none";
153 static DEFINE_SPINLOCK(ipmi_read_lock);
154 static char data_to_read;
155 static DECLARE_WAIT_QUEUE_HEAD(read_q);
156 static struct fasync_struct *fasync_q;
157 static atomic_t pretimeout_since_last_heartbeat;
158 static char expect_close;
159 
160 static int ifnum_to_use = -1;
161 
162 /* Parameters to ipmi_set_timeout */
163 #define IPMI_SET_TIMEOUT_NO_HB			0
164 #define IPMI_SET_TIMEOUT_HB_IF_NECESSARY	1
165 #define IPMI_SET_TIMEOUT_FORCE_HB		2
166 
167 static int ipmi_set_timeout(int do_heartbeat);
168 static void ipmi_register_watchdog(int ipmi_intf);
169 static void ipmi_unregister_watchdog(int ipmi_intf);
170 
171 /*
172  * If true, the driver will start running as soon as it is configured
173  * and ready.
174  */
175 static int start_now;
176 
177 static int set_param_timeout(const char *val, const struct kernel_param *kp)
178 {
179 	char *endp;
180 	int  l;
181 	int  rv = 0;
182 
183 	if (!val)
184 		return -EINVAL;
185 	l = simple_strtoul(val, &endp, 0);
186 	if (endp == val)
187 		return -EINVAL;
188 
189 	*((int *)kp->arg) = l;
190 	if (watchdog_user)
191 		rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
192 
193 	return rv;
194 }
195 
196 static const struct kernel_param_ops param_ops_timeout = {
197 	.set = set_param_timeout,
198 	.get = param_get_int,
199 };
200 #define param_check_timeout param_check_int
201 
202 typedef int (*action_fn)(const char *intval, char *outval);
203 
204 static int action_op(const char *inval, char *outval);
205 static int preaction_op(const char *inval, char *outval);
206 static int preop_op(const char *inval, char *outval);
207 static void check_parms(void);
208 
209 static int set_param_str(const char *val, const struct kernel_param *kp)
210 {
211 	action_fn  fn = (action_fn) kp->arg;
212 	int        rv = 0;
213 	char       valcp[16];
214 	char       *s;
215 
216 	strscpy(valcp, val, 16);
217 
218 	s = strstrip(valcp);
219 
220 	rv = fn(s, NULL);
221 	if (rv)
222 		goto out;
223 
224 	check_parms();
225 	if (watchdog_user)
226 		rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
227 
228  out:
229 	return rv;
230 }
231 
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 		if (!oops_in_progress)
347 			complete(&msg_wait);
348 	}
349 }
350 static void msg_free_recv(struct ipmi_recv_msg *msg)
351 {
352 	if (atomic_dec_and_test(&msg_tofree)) {
353 		if (!oops_in_progress)
354 			complete(&msg_wait);
355 	}
356 }
357 static struct ipmi_smi_msg smi_msg = INIT_IPMI_SMI_MSG(msg_free_smi);
358 static struct ipmi_recv_msg recv_msg = INIT_IPMI_RECV_MSG(msg_free_recv);
359 
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 		atomic_set(&msg_tofree, 0);
439 		return rv;
440 	}
441 
442 	wait_for_completion(&msg_wait);
443 
444 	if ((do_heartbeat == IPMI_SET_TIMEOUT_FORCE_HB)
445 		|| ((send_heartbeat_now)
446 		    && (do_heartbeat == IPMI_SET_TIMEOUT_HB_IF_NECESSARY)))
447 		rv = __ipmi_heartbeat();
448 
449 	return rv;
450 }
451 
452 static int ipmi_set_timeout(int do_heartbeat)
453 {
454 	int rv;
455 
456 	mutex_lock(&ipmi_watchdog_mutex);
457 	rv = _ipmi_set_timeout(do_heartbeat);
458 	mutex_unlock(&ipmi_watchdog_mutex);
459 
460 	return rv;
461 }
462 
463 static atomic_t panic_done_count = ATOMIC_INIT(0);
464 
465 static void panic_smi_free(struct ipmi_smi_msg *msg)
466 {
467 	atomic_dec(&panic_done_count);
468 }
469 static void panic_recv_free(struct ipmi_recv_msg *msg)
470 {
471 	atomic_dec(&panic_done_count);
472 }
473 
474 static struct ipmi_smi_msg panic_halt_heartbeat_smi_msg =
475 	INIT_IPMI_SMI_MSG(panic_smi_free);
476 static struct ipmi_recv_msg panic_halt_heartbeat_recv_msg =
477 	INIT_IPMI_RECV_MSG(panic_recv_free);
478 
479 static void panic_halt_ipmi_heartbeat(void)
480 {
481 	struct kernel_ipmi_msg             msg;
482 	struct ipmi_system_interface_addr addr;
483 	int rv;
484 
485 	/*
486 	 * Don't reset the timer if we have the timer turned off, that
487 	 * re-enables the watchdog.
488 	 */
489 	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
490 		return;
491 
492 	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
493 	addr.channel = IPMI_BMC_CHANNEL;
494 	addr.lun = 0;
495 
496 	msg.netfn = 0x06;
497 	msg.cmd = IPMI_WDOG_RESET_TIMER;
498 	msg.data = NULL;
499 	msg.data_len = 0;
500 	atomic_add(2, &panic_done_count);
501 	rv = ipmi_request_supply_msgs(watchdog_user,
502 				      (struct ipmi_addr *) &addr,
503 				      0,
504 				      &msg,
505 				      NULL,
506 				      &panic_halt_heartbeat_smi_msg,
507 				      &panic_halt_heartbeat_recv_msg,
508 				      1);
509 	if (rv)
510 		atomic_sub(2, &panic_done_count);
511 }
512 
513 static struct ipmi_smi_msg panic_halt_smi_msg =
514 	INIT_IPMI_SMI_MSG(panic_smi_free);
515 static struct ipmi_recv_msg panic_halt_recv_msg =
516 	INIT_IPMI_RECV_MSG(panic_recv_free);
517 
518 /*
519  * Special call, doesn't claim any locks.  This is only to be called
520  * at panic or halt time, in run-to-completion mode, when the caller
521  * is the only CPU and the only thing that will be going is these IPMI
522  * calls.
523  */
524 static void panic_halt_ipmi_set_timeout(void)
525 {
526 	int send_heartbeat_now;
527 	int rv;
528 
529 	/* Wait for the messages to be free. */
530 	while (atomic_read(&panic_done_count) != 0)
531 		ipmi_poll_interface(watchdog_user);
532 	atomic_add(2, &panic_done_count);
533 	rv = __ipmi_set_timeout(&panic_halt_smi_msg,
534 				&panic_halt_recv_msg,
535 				&send_heartbeat_now);
536 	if (rv) {
537 		atomic_sub(2, &panic_done_count);
538 		pr_warn("Unable to extend the watchdog timeout\n");
539 	} else {
540 		if (send_heartbeat_now)
541 			panic_halt_ipmi_heartbeat();
542 	}
543 	while (atomic_read(&panic_done_count) != 0)
544 		ipmi_poll_interface(watchdog_user);
545 }
546 
547 static int __ipmi_heartbeat(void)
548 {
549 	struct kernel_ipmi_msg msg;
550 	int rv;
551 	struct ipmi_system_interface_addr addr;
552 	int timeout_retries = 0;
553 
554 restart:
555 	/*
556 	 * Don't reset the timer if we have the timer turned off, that
557 	 * re-enables the watchdog.
558 	 */
559 	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
560 		return 0;
561 
562 	atomic_set(&msg_tofree, 2);
563 
564 	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
565 	addr.channel = IPMI_BMC_CHANNEL;
566 	addr.lun = 0;
567 
568 	msg.netfn = 0x06;
569 	msg.cmd = IPMI_WDOG_RESET_TIMER;
570 	msg.data = NULL;
571 	msg.data_len = 0;
572 	rv = ipmi_request_supply_msgs(watchdog_user,
573 				      (struct ipmi_addr *) &addr,
574 				      0,
575 				      &msg,
576 				      NULL,
577 				      &smi_msg,
578 				      &recv_msg,
579 				      1);
580 	if (rv) {
581 		atomic_set(&msg_tofree, 0);
582 		pr_warn("heartbeat send failure: %d\n", rv);
583 		return rv;
584 	}
585 
586 	/* Wait for the heartbeat to be sent. */
587 	wait_for_completion(&msg_wait);
588 
589 	if (recv_msg.msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)  {
590 		timeout_retries++;
591 		if (timeout_retries > 3) {
592 			pr_err("Unable to restore the IPMI watchdog's settings, giving up\n");
593 			rv = -EIO;
594 			goto out;
595 		}
596 
597 		/*
598 		 * The timer was not initialized, that means the BMC was
599 		 * probably reset and lost the watchdog information.  Attempt
600 		 * to restore the timer's info.  Note that we still hold
601 		 * the heartbeat lock, to keep a heartbeat from happening
602 		 * in this process, so must say no heartbeat to avoid a
603 		 * deadlock on this mutex
604 		 */
605 		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
606 		if (rv) {
607 			pr_err("Unable to send the command to set the watchdog's settings, giving up\n");
608 			goto out;
609 		}
610 
611 		/* Might need a heartbeat send, go ahead and do it. */
612 		goto restart;
613 	} else if (recv_msg.msg.data[0] != 0) {
614 		/*
615 		 * Got an error in the heartbeat response.  It was already
616 		 * reported in ipmi_wdog_msg_handler, but we should return
617 		 * an error here.
618 		 */
619 		rv = -EINVAL;
620 	}
621 
622 out:
623 	return rv;
624 }
625 
626 static int _ipmi_heartbeat(void)
627 {
628 	int rv;
629 
630 	if (!watchdog_user)
631 		return -ENODEV;
632 
633 	if (ipmi_start_timer_on_heartbeat) {
634 		ipmi_start_timer_on_heartbeat = 0;
635 		ipmi_watchdog_state = action_val;
636 		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
637 	} else if (atomic_cmpxchg(&pretimeout_since_last_heartbeat, 1, 0)) {
638 		/*
639 		 * A pretimeout occurred, make sure we set the timeout.
640 		 * We don't want to set the action, though, we want to
641 		 * leave that alone (thus it can't be combined with the
642 		 * above operation.
643 		 */
644 		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
645 	} else {
646 		rv = __ipmi_heartbeat();
647 	}
648 
649 	return rv;
650 }
651 
652 static int ipmi_heartbeat(void)
653 {
654 	int rv;
655 
656 	mutex_lock(&ipmi_watchdog_mutex);
657 	rv = _ipmi_heartbeat();
658 	mutex_unlock(&ipmi_watchdog_mutex);
659 
660 	return rv;
661 }
662 
663 static const struct watchdog_info ident = {
664 	.options	= 0,	/* WDIOF_SETTIMEOUT, */
665 	.firmware_version = 1,
666 	.identity	= "IPMI"
667 };
668 
669 static int ipmi_ioctl(struct file *file,
670 		      unsigned int cmd, unsigned long arg)
671 {
672 	void __user *argp = (void __user *)arg;
673 	int i;
674 	int val;
675 
676 	switch (cmd) {
677 	case WDIOC_GETSUPPORT:
678 		i = copy_to_user(argp, &ident, sizeof(ident));
679 		return i ? -EFAULT : 0;
680 
681 	case WDIOC_SETTIMEOUT:
682 		i = copy_from_user(&val, argp, sizeof(int));
683 		if (i)
684 			return -EFAULT;
685 		timeout = val;
686 		return _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
687 
688 	case WDIOC_GETTIMEOUT:
689 		i = copy_to_user(argp, &timeout, sizeof(timeout));
690 		if (i)
691 			return -EFAULT;
692 		return 0;
693 
694 	case WDIOC_SETPRETIMEOUT:
695 		i = copy_from_user(&val, argp, sizeof(int));
696 		if (i)
697 			return -EFAULT;
698 		pretimeout = val;
699 		return _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
700 
701 	case WDIOC_GETPRETIMEOUT:
702 		i = copy_to_user(argp, &pretimeout, sizeof(pretimeout));
703 		if (i)
704 			return -EFAULT;
705 		return 0;
706 
707 	case WDIOC_KEEPALIVE:
708 		return _ipmi_heartbeat();
709 
710 	case WDIOC_SETOPTIONS:
711 		i = copy_from_user(&val, argp, sizeof(int));
712 		if (i)
713 			return -EFAULT;
714 		if (val & WDIOS_DISABLECARD) {
715 			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
716 			_ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
717 			ipmi_start_timer_on_heartbeat = 0;
718 		}
719 
720 		if (val & WDIOS_ENABLECARD) {
721 			ipmi_watchdog_state = action_val;
722 			_ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
723 		}
724 		return 0;
725 
726 	case WDIOC_GETSTATUS:
727 		val = 0;
728 		i = copy_to_user(argp, &val, sizeof(val));
729 		if (i)
730 			return -EFAULT;
731 		return 0;
732 
733 	default:
734 		return -ENOIOCTLCMD;
735 	}
736 }
737 
738 static long ipmi_unlocked_ioctl(struct file *file,
739 				unsigned int cmd,
740 				unsigned long arg)
741 {
742 	int ret;
743 
744 	mutex_lock(&ipmi_watchdog_mutex);
745 	ret = ipmi_ioctl(file, cmd, arg);
746 	mutex_unlock(&ipmi_watchdog_mutex);
747 
748 	return ret;
749 }
750 
751 static ssize_t ipmi_write(struct file *file,
752 			  const char  __user *buf,
753 			  size_t      len,
754 			  loff_t      *ppos)
755 {
756 	int rv;
757 
758 	if (len) {
759 		if (!nowayout) {
760 			size_t i;
761 
762 			/* In case it was set long ago */
763 			expect_close = 0;
764 
765 			for (i = 0; i != len; i++) {
766 				char c;
767 
768 				if (get_user(c, buf + i))
769 					return -EFAULT;
770 				if (c == 'V')
771 					expect_close = 42;
772 			}
773 		}
774 		rv = ipmi_heartbeat();
775 		if (rv)
776 			return rv;
777 	}
778 	return len;
779 }
780 
781 static ssize_t ipmi_read(struct file *file,
782 			 char        __user *buf,
783 			 size_t      count,
784 			 loff_t      *ppos)
785 {
786 	int          rv = 0;
787 	wait_queue_entry_t wait;
788 
789 	if (count <= 0)
790 		return 0;
791 
792 	/*
793 	 * Reading returns if the pretimeout has gone off, and it only does
794 	 * it once per pretimeout.
795 	 */
796 	spin_lock_irq(&ipmi_read_lock);
797 	if (!data_to_read) {
798 		if (file->f_flags & O_NONBLOCK) {
799 			rv = -EAGAIN;
800 			goto out;
801 		}
802 
803 		init_waitqueue_entry(&wait, current);
804 		add_wait_queue(&read_q, &wait);
805 		while (!data_to_read) {
806 			set_current_state(TASK_INTERRUPTIBLE);
807 			spin_unlock_irq(&ipmi_read_lock);
808 			schedule();
809 			spin_lock_irq(&ipmi_read_lock);
810 		}
811 		remove_wait_queue(&read_q, &wait);
812 
813 		if (signal_pending(current)) {
814 			rv = -ERESTARTSYS;
815 			goto out;
816 		}
817 	}
818 	data_to_read = 0;
819 
820  out:
821 	spin_unlock_irq(&ipmi_read_lock);
822 
823 	if (rv == 0) {
824 		if (copy_to_user(buf, &data_to_read, 1))
825 			rv = -EFAULT;
826 		else
827 			rv = 1;
828 	}
829 
830 	return rv;
831 }
832 
833 static int ipmi_open(struct inode *ino, struct file *filep)
834 {
835 	switch (iminor(ino)) {
836 	case WATCHDOG_MINOR:
837 		if (test_and_set_bit(0, &ipmi_wdog_open))
838 			return -EBUSY;
839 
840 
841 		/*
842 		 * Don't start the timer now, let it start on the
843 		 * first heartbeat.
844 		 */
845 		ipmi_start_timer_on_heartbeat = 1;
846 		return stream_open(ino, filep);
847 
848 	default:
849 		return (-ENODEV);
850 	}
851 }
852 
853 static __poll_t ipmi_poll(struct file *file, poll_table *wait)
854 {
855 	__poll_t mask = 0;
856 
857 	poll_wait(file, &read_q, wait);
858 
859 	spin_lock_irq(&ipmi_read_lock);
860 	if (data_to_read)
861 		mask |= (EPOLLIN | EPOLLRDNORM);
862 	spin_unlock_irq(&ipmi_read_lock);
863 
864 	return mask;
865 }
866 
867 static int ipmi_fasync(int fd, struct file *file, int on)
868 {
869 	int result;
870 
871 	result = fasync_helper(fd, file, on, &fasync_q);
872 
873 	return (result);
874 }
875 
876 static int ipmi_close(struct inode *ino, struct file *filep)
877 {
878 	if (iminor(ino) == WATCHDOG_MINOR) {
879 		if (expect_close == 42) {
880 			mutex_lock(&ipmi_watchdog_mutex);
881 			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
882 			_ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
883 			mutex_unlock(&ipmi_watchdog_mutex);
884 		} else {
885 			pr_crit("Unexpected close, not stopping watchdog!\n");
886 			ipmi_heartbeat();
887 		}
888 		clear_bit(0, &ipmi_wdog_open);
889 	}
890 
891 	expect_close = 0;
892 
893 	return 0;
894 }
895 
896 static const struct file_operations ipmi_wdog_fops = {
897 	.owner   = THIS_MODULE,
898 	.read    = ipmi_read,
899 	.poll    = ipmi_poll,
900 	.write   = ipmi_write,
901 	.unlocked_ioctl = ipmi_unlocked_ioctl,
902 	.compat_ioctl	= compat_ptr_ioctl,
903 	.open    = ipmi_open,
904 	.release = ipmi_close,
905 	.fasync  = ipmi_fasync,
906 	.llseek  = no_llseek,
907 };
908 
909 static struct miscdevice ipmi_wdog_miscdev = {
910 	.minor		= WATCHDOG_MINOR,
911 	.name		= "watchdog",
912 	.fops		= &ipmi_wdog_fops
913 };
914 
915 static void ipmi_wdog_msg_handler(struct ipmi_recv_msg *msg,
916 				  void                 *handler_data)
917 {
918 	if (msg->msg.cmd == IPMI_WDOG_RESET_TIMER &&
919 			msg->msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)
920 		pr_info("response: The IPMI controller appears to have been reset, will attempt to reinitialize the watchdog timer\n");
921 	else if (msg->msg.data[0] != 0)
922 		pr_err("response: Error %x on cmd %x\n",
923 		       msg->msg.data[0],
924 		       msg->msg.cmd);
925 
926 	ipmi_free_recv_msg(msg);
927 }
928 
929 static void ipmi_wdog_pretimeout_handler(void *handler_data)
930 {
931 	if (preaction_val != WDOG_PRETIMEOUT_NONE) {
932 		if (preop_val == WDOG_PREOP_PANIC) {
933 			if (atomic_inc_and_test(&preop_panic_excl))
934 				panic("Watchdog pre-timeout");
935 		} else if (preop_val == WDOG_PREOP_GIVE_DATA) {
936 			unsigned long flags;
937 
938 			spin_lock_irqsave(&ipmi_read_lock, flags);
939 			data_to_read = 1;
940 			wake_up_interruptible(&read_q);
941 			kill_fasync(&fasync_q, SIGIO, POLL_IN);
942 			spin_unlock_irqrestore(&ipmi_read_lock, flags);
943 		}
944 	}
945 
946 	/*
947 	 * On some machines, the heartbeat will give an error and not
948 	 * work unless we re-enable the timer.  So do so.
949 	 */
950 	atomic_set(&pretimeout_since_last_heartbeat, 1);
951 }
952 
953 static void ipmi_wdog_panic_handler(void *user_data)
954 {
955 	static int panic_event_handled;
956 
957 	/*
958 	 * On a panic, if we have a panic timeout, make sure to extend
959 	 * the watchdog timer to a reasonable value to complete the
960 	 * panic, if the watchdog timer is running.  Plus the
961 	 * pretimeout is meaningless at panic time.
962 	 */
963 	if (watchdog_user && !panic_event_handled &&
964 	    ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
965 		/* Make sure we do this only once. */
966 		panic_event_handled = 1;
967 
968 		timeout = panic_wdt_timeout;
969 		pretimeout = 0;
970 		panic_halt_ipmi_set_timeout();
971 	}
972 }
973 
974 static const struct ipmi_user_hndl ipmi_hndlrs = {
975 	.ipmi_recv_hndl           = ipmi_wdog_msg_handler,
976 	.ipmi_watchdog_pretimeout = ipmi_wdog_pretimeout_handler,
977 	.ipmi_panic_handler       = ipmi_wdog_panic_handler
978 };
979 
980 static void ipmi_register_watchdog(int ipmi_intf)
981 {
982 	int rv = -EBUSY;
983 
984 	if (watchdog_user)
985 		goto out;
986 
987 	if ((ifnum_to_use >= 0) && (ifnum_to_use != ipmi_intf))
988 		goto out;
989 
990 	watchdog_ifnum = ipmi_intf;
991 
992 	rv = ipmi_create_user(ipmi_intf, &ipmi_hndlrs, NULL, &watchdog_user);
993 	if (rv < 0) {
994 		pr_crit("Unable to register with ipmi\n");
995 		goto out;
996 	}
997 
998 	rv = ipmi_get_version(watchdog_user,
999 			      &ipmi_version_major,
1000 			      &ipmi_version_minor);
1001 	if (rv) {
1002 		pr_warn("Unable to get IPMI version, assuming 1.0\n");
1003 		ipmi_version_major = 1;
1004 		ipmi_version_minor = 0;
1005 	}
1006 
1007 	rv = misc_register(&ipmi_wdog_miscdev);
1008 	if (rv < 0) {
1009 		ipmi_destroy_user(watchdog_user);
1010 		watchdog_user = NULL;
1011 		pr_crit("Unable to register misc device\n");
1012 	}
1013 
1014 #ifdef HAVE_DIE_NMI
1015 	if (nmi_handler_registered) {
1016 		int old_pretimeout = pretimeout;
1017 		int old_timeout = timeout;
1018 		int old_preop_val = preop_val;
1019 
1020 		/*
1021 		 * Set the pretimeout to go off in a second and give
1022 		 * ourselves plenty of time to stop the timer.
1023 		 */
1024 		ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
1025 		preop_val = WDOG_PREOP_NONE; /* Make sure nothing happens */
1026 		pretimeout = 99;
1027 		timeout = 100;
1028 
1029 		testing_nmi = 1;
1030 
1031 		rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
1032 		if (rv) {
1033 			pr_warn("Error starting timer to test NMI: 0x%x.  The NMI pretimeout will likely not work\n",
1034 				rv);
1035 			rv = 0;
1036 			goto out_restore;
1037 		}
1038 
1039 		msleep(1500);
1040 
1041 		if (testing_nmi != 2) {
1042 			pr_warn("IPMI NMI didn't seem to occur.  The NMI pretimeout will likely not work\n");
1043 		}
1044  out_restore:
1045 		testing_nmi = 0;
1046 		preop_val = old_preop_val;
1047 		pretimeout = old_pretimeout;
1048 		timeout = old_timeout;
1049 	}
1050 #endif
1051 
1052  out:
1053 	if ((start_now) && (rv == 0)) {
1054 		/* Run from startup, so start the timer now. */
1055 		start_now = 0; /* Disable this function after first startup. */
1056 		ipmi_watchdog_state = action_val;
1057 		ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
1058 		pr_info("Starting now!\n");
1059 	} else {
1060 		/* Stop the timer now. */
1061 		ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
1062 		ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
1063 	}
1064 }
1065 
1066 static void ipmi_unregister_watchdog(int ipmi_intf)
1067 {
1068 	int rv;
1069 	struct ipmi_user *loc_user = watchdog_user;
1070 
1071 	if (!loc_user)
1072 		return;
1073 
1074 	if (watchdog_ifnum != ipmi_intf)
1075 		return;
1076 
1077 	/* Make sure no one can call us any more. */
1078 	misc_deregister(&ipmi_wdog_miscdev);
1079 
1080 	watchdog_user = NULL;
1081 
1082 	/*
1083 	 * Wait to make sure the message makes it out.  The lower layer has
1084 	 * pointers to our buffers, we want to make sure they are done before
1085 	 * we release our memory.
1086 	 */
1087 	while (atomic_read(&msg_tofree))
1088 		msg_free_smi(NULL);
1089 
1090 	mutex_lock(&ipmi_watchdog_mutex);
1091 
1092 	/* Disconnect from IPMI. */
1093 	rv = ipmi_destroy_user(loc_user);
1094 	if (rv)
1095 		pr_warn("error unlinking from IPMI: %d\n",  rv);
1096 
1097 	/* If it comes back, restart it properly. */
1098 	ipmi_start_timer_on_heartbeat = 1;
1099 
1100 	mutex_unlock(&ipmi_watchdog_mutex);
1101 }
1102 
1103 #ifdef HAVE_DIE_NMI
1104 static int
1105 ipmi_nmi(unsigned int val, struct pt_regs *regs)
1106 {
1107 	/*
1108 	 * If we get here, it's an NMI that's not a memory or I/O
1109 	 * error.  We can't truly tell if it's from IPMI or not
1110 	 * without sending a message, and sending a message is almost
1111 	 * impossible because of locking.
1112 	 */
1113 
1114 	if (testing_nmi) {
1115 		testing_nmi = 2;
1116 		return NMI_HANDLED;
1117 	}
1118 
1119 	/* If we are not expecting a timeout, ignore it. */
1120 	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
1121 		return NMI_DONE;
1122 
1123 	if (preaction_val != WDOG_PRETIMEOUT_NMI)
1124 		return NMI_DONE;
1125 
1126 	/*
1127 	 * If no one else handled the NMI, we assume it was the IPMI
1128 	 * watchdog.
1129 	 */
1130 	if (preop_val == WDOG_PREOP_PANIC) {
1131 		/* On some machines, the heartbeat will give
1132 		   an error and not work unless we re-enable
1133 		   the timer.   So do so. */
1134 		atomic_set(&pretimeout_since_last_heartbeat, 1);
1135 		if (atomic_inc_and_test(&preop_panic_excl))
1136 			nmi_panic(regs, "pre-timeout");
1137 	}
1138 
1139 	return NMI_HANDLED;
1140 }
1141 #endif
1142 
1143 static int wdog_reboot_handler(struct notifier_block *this,
1144 			       unsigned long         code,
1145 			       void                  *unused)
1146 {
1147 	static int reboot_event_handled;
1148 
1149 	if ((watchdog_user) && (!reboot_event_handled)) {
1150 		/* Make sure we only do this once. */
1151 		reboot_event_handled = 1;
1152 
1153 		if (code == SYS_POWER_OFF || code == SYS_HALT) {
1154 			/* Disable the WDT if we are shutting down. */
1155 			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
1156 			ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
1157 		} else if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
1158 			/* Set a long timer to let the reboot happen or
1159 			   reset if it hangs, but only if the watchdog
1160 			   timer was already running. */
1161 			if (timeout < 120)
1162 				timeout = 120;
1163 			pretimeout = 0;
1164 			ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
1165 			ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
1166 		}
1167 	}
1168 	return NOTIFY_OK;
1169 }
1170 
1171 static struct notifier_block wdog_reboot_notifier = {
1172 	.notifier_call	= wdog_reboot_handler,
1173 	.next		= NULL,
1174 	.priority	= 0
1175 };
1176 
1177 static void ipmi_new_smi(int if_num, struct device *device)
1178 {
1179 	ipmi_register_watchdog(if_num);
1180 }
1181 
1182 static void ipmi_smi_gone(int if_num)
1183 {
1184 	ipmi_unregister_watchdog(if_num);
1185 }
1186 
1187 static struct ipmi_smi_watcher smi_watcher = {
1188 	.owner    = THIS_MODULE,
1189 	.new_smi  = ipmi_new_smi,
1190 	.smi_gone = ipmi_smi_gone
1191 };
1192 
1193 static int action_op(const char *inval, char *outval)
1194 {
1195 	if (outval)
1196 		strcpy(outval, action);
1197 
1198 	if (!inval)
1199 		return 0;
1200 
1201 	if (strcmp(inval, "reset") == 0)
1202 		action_val = WDOG_TIMEOUT_RESET;
1203 	else if (strcmp(inval, "none") == 0)
1204 		action_val = WDOG_TIMEOUT_NONE;
1205 	else if (strcmp(inval, "power_cycle") == 0)
1206 		action_val = WDOG_TIMEOUT_POWER_CYCLE;
1207 	else if (strcmp(inval, "power_off") == 0)
1208 		action_val = WDOG_TIMEOUT_POWER_DOWN;
1209 	else
1210 		return -EINVAL;
1211 	strcpy(action, inval);
1212 	return 0;
1213 }
1214 
1215 static int preaction_op(const char *inval, char *outval)
1216 {
1217 	if (outval)
1218 		strcpy(outval, preaction);
1219 
1220 	if (!inval)
1221 		return 0;
1222 
1223 	if (strcmp(inval, "pre_none") == 0)
1224 		preaction_val = WDOG_PRETIMEOUT_NONE;
1225 	else if (strcmp(inval, "pre_smi") == 0)
1226 		preaction_val = WDOG_PRETIMEOUT_SMI;
1227 #ifdef HAVE_DIE_NMI
1228 	else if (strcmp(inval, "pre_nmi") == 0)
1229 		preaction_val = WDOG_PRETIMEOUT_NMI;
1230 #endif
1231 	else if (strcmp(inval, "pre_int") == 0)
1232 		preaction_val = WDOG_PRETIMEOUT_MSG_INT;
1233 	else
1234 		return -EINVAL;
1235 	strcpy(preaction, inval);
1236 	return 0;
1237 }
1238 
1239 static int preop_op(const char *inval, char *outval)
1240 {
1241 	if (outval)
1242 		strcpy(outval, preop);
1243 
1244 	if (!inval)
1245 		return 0;
1246 
1247 	if (strcmp(inval, "preop_none") == 0)
1248 		preop_val = WDOG_PREOP_NONE;
1249 	else if (strcmp(inval, "preop_panic") == 0)
1250 		preop_val = WDOG_PREOP_PANIC;
1251 	else if (strcmp(inval, "preop_give_data") == 0)
1252 		preop_val = WDOG_PREOP_GIVE_DATA;
1253 	else
1254 		return -EINVAL;
1255 	strcpy(preop, inval);
1256 	return 0;
1257 }
1258 
1259 static void check_parms(void)
1260 {
1261 #ifdef HAVE_DIE_NMI
1262 	int do_nmi = 0;
1263 	int rv;
1264 
1265 	if (preaction_val == WDOG_PRETIMEOUT_NMI) {
1266 		do_nmi = 1;
1267 		if (preop_val == WDOG_PREOP_GIVE_DATA) {
1268 			pr_warn("Pretimeout op is to give data but NMI pretimeout is enabled, setting pretimeout op to none\n");
1269 			preop_op("preop_none", NULL);
1270 			do_nmi = 0;
1271 		}
1272 	}
1273 	if (do_nmi && !nmi_handler_registered) {
1274 		rv = register_nmi_handler(NMI_UNKNOWN, ipmi_nmi, 0,
1275 						"ipmi");
1276 		if (rv) {
1277 			pr_warn("Can't register nmi handler\n");
1278 			return;
1279 		} else
1280 			nmi_handler_registered = 1;
1281 	} else if (!do_nmi && nmi_handler_registered) {
1282 		unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
1283 		nmi_handler_registered = 0;
1284 	}
1285 #endif
1286 }
1287 
1288 static int __init ipmi_wdog_init(void)
1289 {
1290 	int rv;
1291 
1292 	if (action_op(action, NULL)) {
1293 		action_op("reset", NULL);
1294 		pr_info("Unknown action '%s', defaulting to reset\n", action);
1295 	}
1296 
1297 	if (preaction_op(preaction, NULL)) {
1298 		preaction_op("pre_none", NULL);
1299 		pr_info("Unknown preaction '%s', defaulting to none\n",
1300 			preaction);
1301 	}
1302 
1303 	if (preop_op(preop, NULL)) {
1304 		preop_op("preop_none", NULL);
1305 		pr_info("Unknown preop '%s', defaulting to none\n", preop);
1306 	}
1307 
1308 	check_parms();
1309 
1310 	register_reboot_notifier(&wdog_reboot_notifier);
1311 
1312 	rv = ipmi_smi_watcher_register(&smi_watcher);
1313 	if (rv) {
1314 #ifdef HAVE_DIE_NMI
1315 		if (nmi_handler_registered)
1316 			unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
1317 #endif
1318 		unregister_reboot_notifier(&wdog_reboot_notifier);
1319 		pr_warn("can't register smi watcher\n");
1320 		return rv;
1321 	}
1322 
1323 	pr_info("driver initialized\n");
1324 
1325 	return 0;
1326 }
1327 
1328 static void __exit ipmi_wdog_exit(void)
1329 {
1330 	ipmi_smi_watcher_unregister(&smi_watcher);
1331 	ipmi_unregister_watchdog(watchdog_ifnum);
1332 
1333 #ifdef HAVE_DIE_NMI
1334 	if (nmi_handler_registered)
1335 		unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
1336 #endif
1337 
1338 	unregister_reboot_notifier(&wdog_reboot_notifier);
1339 }
1340 module_exit(ipmi_wdog_exit);
1341 module_init(ipmi_wdog_init);
1342 MODULE_LICENSE("GPL");
1343 MODULE_AUTHOR("Corey Minyard <minyard@mvista.com>");
1344 MODULE_DESCRIPTION("watchdog timer based upon the IPMI interface.");
1345