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