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
126static DEFINE_MUTEX(ipmi_watchdog_mutex);
127static bool nowayout = WATCHDOG_NOWAYOUT;
128
129static struct ipmi_user *watchdog_user;
130static int watchdog_ifnum;
131
132/* Default the timeout to 10 seconds. */
133static int timeout = 10;
134
135/* The pre-timeout is disabled by default. */
136static int pretimeout;
137
138/* Default timeout to set on panic */
139static int panic_wdt_timeout = 255;
140
141/* Default action is to reset the board on a timeout. */
142static unsigned char action_val = WDOG_TIMEOUT_RESET;
143
144static char action[16] = "reset";
145
146static unsigned char preaction_val = WDOG_PRETIMEOUT_NONE;
147
148static char preaction[16] = "pre_none";
149
150static unsigned char preop_val = WDOG_PREOP_NONE;
151
152static char preop[16] = "preop_none";
153static DEFINE_SPINLOCK(ipmi_read_lock);
154static char data_to_read;
155static DECLARE_WAIT_QUEUE_HEAD(read_q);
156static struct fasync_struct *fasync_q;
157static atomic_t pretimeout_since_last_heartbeat;
158static char expect_close;
159
160static 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
167static int ipmi_set_timeout(int do_heartbeat);
168static void ipmi_register_watchdog(int ipmi_intf);
169static 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 */
175static int start_now;
176
177static 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
196static 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
202typedef int (*action_fn)(const char *intval, char *outval);
203
204static int action_op(const char *inval, char *outval);
205static int preaction_op(const char *inval, char *outval);
206static int preop_op(const char *inval, char *outval);
207static void check_parms(void);
208
209static 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(p: valcp, q: val, size: 16);
217
218 s = strstrip(str: 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
232static 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
249static 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(ipmi_intf: watchdog_ifnum);
258 ipmi_register_watchdog(ipmi_intf: ifnum_to_use);
259 return 0;
260}
261
262static 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
269static const struct kernel_param_ops param_ops_str = {
270 .set = set_param_str,
271 .get = get_param_str,
272};
273
274module_param(ifnum_to_use, wdog_ifnum, 0644);
275MODULE_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
279module_param(timeout, timeout, 0644);
280MODULE_PARM_DESC(timeout, "Timeout value in seconds.");
281
282module_param(pretimeout, timeout, 0644);
283MODULE_PARM_DESC(pretimeout, "Pretimeout value in seconds.");
284
285module_param(panic_wdt_timeout, timeout, 0644);
286MODULE_PARM_DESC(panic_wdt_timeout, "Timeout value on kernel panic in seconds.");
287
288module_param_cb(action, &param_ops_str, action_op, 0644);
289MODULE_PARM_DESC(action, "Timeout action. One of: "
290 "reset, none, power_cycle, power_off.");
291
292module_param_cb(preaction, &param_ops_str, preaction_op, 0644);
293MODULE_PARM_DESC(preaction, "Pretimeout action. One of: "
294 "pre_none, pre_smi, pre_nmi, pre_int.");
295
296module_param_cb(preop, &param_ops_str, preop_op, 0644);
297MODULE_PARM_DESC(preop, "Pretimeout driver operation. One of: "
298 "preop_none, preop_panic, preop_give_data.");
299
300module_param(start_now, int, 0444);
301MODULE_PARM_DESC(start_now, "Set to 1 to start the watchdog as"
302 "soon as the driver is loaded.");
303
304module_param(nowayout, bool, 0644);
305MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
306 "(default=CONFIG_WATCHDOG_NOWAYOUT)");
307
308/* Default state of the timer. */
309static unsigned char ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
310
311/* Is someone using the watchdog? Only one user is allowed. */
312static 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 */
320static int ipmi_start_timer_on_heartbeat;
321
322/* IPMI version of the BMC. */
323static unsigned char ipmi_version_major;
324static unsigned char ipmi_version_minor;
325
326/* If a pretimeout occurs, this is used to allow only one panic to happen. */
327static atomic_t preop_panic_excl = ATOMIC_INIT(-1);
328
329#ifdef HAVE_DIE_NMI
330static int testing_nmi;
331static int nmi_handler_registered;
332#endif
333
334static 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 */
341static atomic_t msg_tofree = ATOMIC_INIT(0);
342static DECLARE_COMPLETION(msg_wait);
343static void msg_free_smi(struct ipmi_smi_msg *msg)
344{
345 if (atomic_dec_and_test(v: &msg_tofree)) {
346 if (!oops_in_progress)
347 complete(&msg_wait);
348 }
349}
350static void msg_free_recv(struct ipmi_recv_msg *msg)
351{
352 if (atomic_dec_and_test(v: &msg_tofree)) {
353 if (!oops_in_progress)
354 complete(&msg_wait);
355 }
356}
357static struct ipmi_smi_msg smi_msg = INIT_IPMI_SMI_MSG(msg_free_smi);
358static struct ipmi_recv_msg recv_msg = INIT_IPMI_RECV_MSG(msg_free_recv);
359
360static 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(user: watchdog_user,
409 addr: (struct ipmi_addr *) &addr,
410 msgid: 0,
411 msg: &msg,
412 NULL,
413 supplied_smi: smi_msg,
414 supplied_recv: recv_msg,
415 priority: 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
424static 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(v: &msg_tofree, i: 2);
433
434 rv = __ipmi_set_timeout(smi_msg: &smi_msg,
435 recv_msg: &recv_msg,
436 send_heartbeat_now: &send_heartbeat_now);
437 if (rv) {
438 atomic_set(v: &msg_tofree, i: 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
452static 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(lock: &ipmi_watchdog_mutex);
459
460 return rv;
461}
462
463static atomic_t panic_done_count = ATOMIC_INIT(0);
464
465static void panic_smi_free(struct ipmi_smi_msg *msg)
466{
467 atomic_dec(v: &panic_done_count);
468}
469static void panic_recv_free(struct ipmi_recv_msg *msg)
470{
471 atomic_dec(v: &panic_done_count);
472}
473
474static struct ipmi_smi_msg panic_halt_heartbeat_smi_msg =
475 INIT_IPMI_SMI_MSG(panic_smi_free);
476static struct ipmi_recv_msg panic_halt_heartbeat_recv_msg =
477 INIT_IPMI_RECV_MSG(panic_recv_free);
478
479static 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(i: 2, v: &panic_done_count);
501 rv = ipmi_request_supply_msgs(user: watchdog_user,
502 addr: (struct ipmi_addr *) &addr,
503 msgid: 0,
504 msg: &msg,
505 NULL,
506 supplied_smi: &panic_halt_heartbeat_smi_msg,
507 supplied_recv: &panic_halt_heartbeat_recv_msg,
508 priority: 1);
509 if (rv)
510 atomic_sub(i: 2, v: &panic_done_count);
511}
512
513static struct ipmi_smi_msg panic_halt_smi_msg =
514 INIT_IPMI_SMI_MSG(panic_smi_free);
515static 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 */
524static 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(v: &panic_done_count) != 0)
531 ipmi_poll_interface(user: watchdog_user);
532 atomic_add(i: 2, v: &panic_done_count);
533 rv = __ipmi_set_timeout(smi_msg: &panic_halt_smi_msg,
534 recv_msg: &panic_halt_recv_msg,
535 send_heartbeat_now: &send_heartbeat_now);
536 if (rv) {
537 atomic_sub(i: 2, v: &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(v: &panic_done_count) != 0)
544 ipmi_poll_interface(user: watchdog_user);
545}
546
547static 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
554restart:
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(v: &msg_tofree, i: 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(user: watchdog_user,
573 addr: (struct ipmi_addr *) &addr,
574 msgid: 0,
575 msg: &msg,
576 NULL,
577 supplied_smi: &smi_msg,
578 supplied_recv: &recv_msg,
579 priority: 1);
580 if (rv) {
581 atomic_set(v: &msg_tofree, i: 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
622out:
623 return rv;
624}
625
626static 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(v: &pretimeout_since_last_heartbeat, old: 1, new: 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
652static int ipmi_heartbeat(void)
653{
654 int rv;
655
656 mutex_lock(&ipmi_watchdog_mutex);
657 rv = _ipmi_heartbeat();
658 mutex_unlock(lock: &ipmi_watchdog_mutex);
659
660 return rv;
661}
662
663static const struct watchdog_info ident = {
664 .options = 0, /* WDIOF_SETTIMEOUT, */
665 .firmware_version = 1,
666 .identity = "IPMI"
667};
668
669static 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(to: argp, from: &ident, n: sizeof(ident));
679 return i ? -EFAULT : 0;
680
681 case WDIOC_SETTIMEOUT:
682 i = copy_from_user(to: &val, from: argp, n: 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(to: argp, from: &timeout, n: sizeof(timeout));
690 if (i)
691 return -EFAULT;
692 return 0;
693
694 case WDIOC_SETPRETIMEOUT:
695 i = copy_from_user(to: &val, from: argp, n: 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(to: argp, from: &pretimeout, n: 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(to: &val, from: argp, n: 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(to: argp, from: &val, n: sizeof(val));
729 if (i)
730 return -EFAULT;
731 return 0;
732
733 default:
734 return -ENOIOCTLCMD;
735 }
736}
737
738static 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(lock: &ipmi_watchdog_mutex);
747
748 return ret;
749}
750
751static 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
781static 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(lock: &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(wq_entry: &wait, current);
804 add_wait_queue(wq_head: &read_q, wq_entry: &wait);
805 while (!data_to_read && !signal_pending(current)) {
806 set_current_state(TASK_INTERRUPTIBLE);
807 spin_unlock_irq(lock: &ipmi_read_lock);
808 schedule();
809 spin_lock_irq(lock: &ipmi_read_lock);
810 }
811 remove_wait_queue(wq_head: &read_q, wq_entry: &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(lock: &ipmi_read_lock);
822
823 if (rv == 0) {
824 if (copy_to_user(to: buf, from: &data_to_read, n: 1))
825 rv = -EFAULT;
826 else
827 rv = 1;
828 }
829
830 return rv;
831}
832
833static int ipmi_open(struct inode *ino, struct file *filep)
834{
835 switch (iminor(inode: ino)) {
836 case WATCHDOG_MINOR:
837 if (test_and_set_bit(nr: 0, addr: &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(inode: ino, filp: filep);
847
848 default:
849 return (-ENODEV);
850 }
851}
852
853static __poll_t ipmi_poll(struct file *file, poll_table *wait)
854{
855 __poll_t mask = 0;
856
857 poll_wait(filp: file, wait_address: &read_q, p: wait);
858
859 spin_lock_irq(lock: &ipmi_read_lock);
860 if (data_to_read)
861 mask |= (EPOLLIN | EPOLLRDNORM);
862 spin_unlock_irq(lock: &ipmi_read_lock);
863
864 return mask;
865}
866
867static 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
876static int ipmi_close(struct inode *ino, struct file *filep)
877{
878 if (iminor(inode: 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(lock: &ipmi_watchdog_mutex);
884 } else {
885 pr_crit("Unexpected close, not stopping watchdog!\n");
886 ipmi_heartbeat();
887 }
888 clear_bit(nr: 0, addr: &ipmi_wdog_open);
889 }
890
891 expect_close = 0;
892
893 return 0;
894}
895
896static 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
909static struct miscdevice ipmi_wdog_miscdev = {
910 .minor = WATCHDOG_MINOR,
911 .name = "watchdog",
912 .fops = &ipmi_wdog_fops
913};
914
915static 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
929static 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(v: &preop_panic_excl))
934 panic(fmt: "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(lock: &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(v: &pretimeout_since_last_heartbeat, i: 1);
951}
952
953static 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
974static 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
980static 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(if_num: ipmi_intf, handler: &ipmi_hndlrs, NULL, user: &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(user: watchdog_user,
999 major: &ipmi_version_major,
1000 minor: &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(misc: &ipmi_wdog_miscdev);
1008 if (rv < 0) {
1009 ipmi_destroy_user(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(msecs: 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
1066static 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(misc: &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(v: &msg_tofree))
1088 msg_free_smi(NULL);
1089
1090 mutex_lock(&ipmi_watchdog_mutex);
1091
1092 /* Disconnect from IPMI. */
1093 rv = ipmi_destroy_user(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(lock: &ipmi_watchdog_mutex);
1101}
1102
1103#ifdef HAVE_DIE_NMI
1104static int
1105ipmi_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(v: &pretimeout_since_last_heartbeat, i: 1);
1135 if (atomic_inc_and_test(v: &preop_panic_excl))
1136 nmi_panic(regs, msg: "pre-timeout");
1137 }
1138
1139 return NMI_HANDLED;
1140}
1141#endif
1142
1143static 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
1171static struct notifier_block wdog_reboot_notifier = {
1172 .notifier_call = wdog_reboot_handler,
1173 .next = NULL,
1174 .priority = 0
1175};
1176
1177static void ipmi_new_smi(int if_num, struct device *device)
1178{
1179 ipmi_register_watchdog(ipmi_intf: if_num);
1180}
1181
1182static void ipmi_smi_gone(int if_num)
1183{
1184 ipmi_unregister_watchdog(ipmi_intf: if_num);
1185}
1186
1187static struct ipmi_smi_watcher smi_watcher = {
1188 .owner = THIS_MODULE,
1189 .new_smi = ipmi_new_smi,
1190 .smi_gone = ipmi_smi_gone
1191};
1192
1193static int action_op(const char *inval, char *outval)
1194{
1195 if (outval)
1196 strcpy(p: outval, q: 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(p: action, q: inval);
1212 return 0;
1213}
1214
1215static int preaction_op(const char *inval, char *outval)
1216{
1217 if (outval)
1218 strcpy(p: outval, q: 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(p: preaction, q: inval);
1236 return 0;
1237}
1238
1239static int preop_op(const char *inval, char *outval)
1240{
1241 if (outval)
1242 strcpy(p: outval, q: 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(p: preop, q: inval);
1256 return 0;
1257}
1258
1259static 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(inval: "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
1288static int __init ipmi_wdog_init(void)
1289{
1290 int rv;
1291
1292 if (action_op(inval: action, NULL)) {
1293 action_op(inval: "reset", NULL);
1294 pr_info("Unknown action '%s', defaulting to reset\n", action);
1295 }
1296
1297 if (preaction_op(inval: preaction, NULL)) {
1298 preaction_op(inval: "pre_none", NULL);
1299 pr_info("Unknown preaction '%s', defaulting to none\n",
1300 preaction);
1301 }
1302
1303 if (preop_op(inval: preop, NULL)) {
1304 preop_op(inval: "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(watcher: &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
1328static void __exit ipmi_wdog_exit(void)
1329{
1330 ipmi_smi_watcher_unregister(watcher: &smi_watcher);
1331 ipmi_unregister_watchdog(ipmi_intf: 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}
1340module_exit(ipmi_wdog_exit);
1341module_init(ipmi_wdog_init);
1342MODULE_LICENSE("GPL");
1343MODULE_AUTHOR("Corey Minyard <minyard@mvista.com>");
1344MODULE_DESCRIPTION("watchdog timer based upon the IPMI interface.");
1345

source code of linux/drivers/char/ipmi/ipmi_watchdog.c