1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2004 Poul-Henning Kamp
5 * Copyright (c) 2013 iXsystems.com,
6 * author: Alfred Perlstein <alfred@freebsd.org>
7 *
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer
15 * in this position and unchanged.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 *
31 */
32
33 #include "opt_ddb.h"
34
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD: stable/12/sys/dev/watchdog/watchdog.c 327505 2018-01-03 00:56:30Z karels $");
37
38 #include <sys/param.h>
39 #include <sys/types.h>
40 #include <sys/systm.h>
41 #include <sys/conf.h>
42 #include <sys/uio.h>
43 #include <sys/kernel.h>
44 #include <sys/kdb.h>
45 #include <sys/malloc.h>
46 #include <sys/module.h>
47 #include <sys/sysctl.h>
48 #include <sys/syslog.h>
49 #include <sys/watchdog.h>
50 #include <sys/bus.h>
51 #include <machine/bus.h>
52
53 #include <sys/syscallsubr.h> /* kern_clock_gettime() */
54
55 static int wd_set_pretimeout(int newtimeout, int disableiftoolong);
56 static void wd_timeout_cb(void *arg);
57
58 static struct callout wd_pretimeo_handle;
59 static int wd_pretimeout;
60 static int wd_pretimeout_act = WD_SOFT_LOG;
61
62 static struct callout wd_softtimeo_handle;
63 static int wd_softtimer; /* true = use softtimer instead of hardware
64 watchdog */
65 static int wd_softtimeout_act = WD_SOFT_LOG; /* action for the software timeout */
66
67 static struct cdev *wd_dev;
68 static volatile u_int wd_last_u; /* last timeout value set by kern_do_pat */
69 static u_int wd_last_u_sysctl; /* last timeout value set by kern_do_pat */
70 static u_int wd_last_u_sysctl_secs; /* wd_last_u in seconds */
71
72 SYSCTL_NODE(_hw, OID_AUTO, watchdog, CTLFLAG_RD, 0, "Main watchdog device");
73 SYSCTL_UINT(_hw_watchdog, OID_AUTO, wd_last_u, CTLFLAG_RD,
74 &wd_last_u_sysctl, 0, "Watchdog last update time");
75 SYSCTL_UINT(_hw_watchdog, OID_AUTO, wd_last_u_secs, CTLFLAG_RD,
76 &wd_last_u_sysctl_secs, 0, "Watchdog last update time");
77
78 static int wd_lastpat_valid = 0;
79 static time_t wd_lastpat = 0; /* when the watchdog was last patted */
80
81 /* Hook for external software watchdog to register for use if needed */
82 void (*wdog_software_attach)(void);
83
84 static void
pow2ns_to_ts(int pow2ns,struct timespec * ts)85 pow2ns_to_ts(int pow2ns, struct timespec *ts)
86 {
87 uint64_t ns;
88
89 ns = 1ULL << pow2ns;
90 ts->tv_sec = ns / 1000000000ULL;
91 ts->tv_nsec = ns % 1000000000ULL;
92 }
93
94 static int
pow2ns_to_ticks(int pow2ns)95 pow2ns_to_ticks(int pow2ns)
96 {
97 struct timeval tv;
98 struct timespec ts;
99
100 pow2ns_to_ts(pow2ns, &ts);
101 TIMESPEC_TO_TIMEVAL(&tv, &ts);
102 return (tvtohz(&tv));
103 }
104
105 static int
seconds_to_pow2ns(int seconds)106 seconds_to_pow2ns(int seconds)
107 {
108 uint64_t power;
109 uint64_t ns;
110 uint64_t shifted;
111
112 ns = ((uint64_t)seconds) * 1000000000ULL;
113 power = flsll(ns);
114 shifted = 1ULL << power;
115 if (shifted <= ns) {
116 power++;
117 }
118 return (power);
119 }
120
121
122 int
wdog_kern_pat(u_int utim)123 wdog_kern_pat(u_int utim)
124 {
125 int error;
126 static int first = 1;
127
128 if ((utim & WD_LASTVAL) != 0 && (utim & WD_INTERVAL) > 0)
129 return (EINVAL);
130
131 if ((utim & WD_LASTVAL) != 0) {
132 /*
133 * if WD_LASTVAL is set, fill in the bits for timeout
134 * from the saved value in wd_last_u.
135 */
136 MPASS((wd_last_u & ~WD_INTERVAL) == 0);
137 utim &= ~WD_LASTVAL;
138 utim |= wd_last_u;
139 } else {
140 /*
141 * Otherwise save the new interval.
142 * This can be zero (to disable the watchdog)
143 */
144 wd_last_u = (utim & WD_INTERVAL);
145 wd_last_u_sysctl = wd_last_u;
146 wd_last_u_sysctl_secs = pow2ns_to_ticks(wd_last_u) / hz;
147 }
148 if ((utim & WD_INTERVAL) == WD_TO_NEVER) {
149 utim = 0;
150
151 /* Assume all is well; watchdog signals failure. */
152 error = 0;
153 } else {
154 /* Assume no watchdog available; watchdog flags success */
155 error = EOPNOTSUPP;
156 }
157 if (wd_softtimer) {
158 if (utim == 0) {
159 callout_stop(&wd_softtimeo_handle);
160 } else {
161 (void) callout_reset(&wd_softtimeo_handle,
162 pow2ns_to_ticks(utim), wd_timeout_cb, "soft");
163 }
164 error = 0;
165 } else {
166 EVENTHANDLER_INVOKE(watchdog_list, utim, &error);
167 }
168 /*
169 * If we no hardware watchdog responded, we have not tried to
170 * attach an external software watchdog, and one is available,
171 * attach it now and retry.
172 */
173 if (error == EOPNOTSUPP && first && *wdog_software_attach != NULL) {
174 (*wdog_software_attach)();
175 EVENTHANDLER_INVOKE(watchdog_list, utim, &error);
176 }
177 first = 0;
178
179 wd_set_pretimeout(wd_pretimeout, true);
180 /*
181 * If we were able to arm/strobe the watchdog, then
182 * update the last time it was strobed for WDIOC_GETTIMELEFT
183 */
184 if (!error) {
185 struct timespec ts;
186
187 error = kern_clock_gettime(curthread /* XXX */,
188 CLOCK_MONOTONIC_FAST, &ts);
189 if (!error) {
190 wd_lastpat = ts.tv_sec;
191 wd_lastpat_valid = 1;
192 }
193 }
194 return (error);
195 }
196
197 static int
wd_valid_act(int act)198 wd_valid_act(int act)
199 {
200
201 if ((act & ~(WD_SOFT_MASK)) != 0)
202 return false;
203 return true;
204 }
205
206 static int
wd_ioctl_patpat(caddr_t data)207 wd_ioctl_patpat(caddr_t data)
208 {
209 u_int u;
210
211 u = *(u_int *)data;
212 if (u & ~(WD_ACTIVE | WD_PASSIVE | WD_LASTVAL | WD_INTERVAL))
213 return (EINVAL);
214 if ((u & (WD_ACTIVE | WD_PASSIVE)) == (WD_ACTIVE | WD_PASSIVE))
215 return (EINVAL);
216 if ((u & (WD_ACTIVE | WD_PASSIVE)) == 0 && ((u & WD_INTERVAL) > 0 ||
217 (u & WD_LASTVAL) != 0))
218 return (EINVAL);
219 if (u & WD_PASSIVE)
220 return (ENOSYS); /* XXX Not implemented yet */
221 u &= ~(WD_ACTIVE | WD_PASSIVE);
222
223 return (wdog_kern_pat(u));
224 }
225
226 static int
wd_get_time_left(struct thread * td,time_t * remainp)227 wd_get_time_left(struct thread *td, time_t *remainp)
228 {
229 struct timespec ts;
230 int error;
231
232 error = kern_clock_gettime(td, CLOCK_MONOTONIC_FAST, &ts);
233 if (error)
234 return (error);
235 if (!wd_lastpat_valid)
236 return (ENOENT);
237 *remainp = ts.tv_sec - wd_lastpat;
238 return (0);
239 }
240
241 static void
wd_timeout_cb(void * arg)242 wd_timeout_cb(void *arg)
243 {
244 const char *type = arg;
245
246 #ifdef DDB
247 if ((wd_pretimeout_act & WD_SOFT_DDB)) {
248 char kdb_why[80];
249 snprintf(kdb_why, sizeof(kdb_why), "watchdog %s-timeout", type);
250 kdb_backtrace();
251 kdb_enter(KDB_WHY_WATCHDOG, kdb_why);
252 }
253 #endif
254 if ((wd_pretimeout_act & WD_SOFT_LOG))
255 log(LOG_EMERG, "watchdog %s-timeout, WD_SOFT_LOG\n", type);
256 if ((wd_pretimeout_act & WD_SOFT_PRINTF))
257 printf("watchdog %s-timeout, WD_SOFT_PRINTF\n", type);
258 if ((wd_pretimeout_act & WD_SOFT_PANIC))
259 panic("watchdog %s-timeout, WD_SOFT_PANIC set", type);
260 }
261
262 /*
263 * Called to manage timeouts.
264 * newtimeout needs to be in the range of 0 to actual watchdog timeout.
265 * if 0, we disable the pre-timeout.
266 * otherwise we set the pre-timeout provided it's not greater than the
267 * current actual watchdog timeout.
268 */
269 static int
wd_set_pretimeout(int newtimeout,int disableiftoolong)270 wd_set_pretimeout(int newtimeout, int disableiftoolong)
271 {
272 u_int utime;
273 struct timespec utime_ts;
274 int timeout_ticks;
275
276 utime = wdog_kern_last_timeout();
277 pow2ns_to_ts(utime, &utime_ts);
278 /* do not permit a pre-timeout >= than the timeout. */
279 if (newtimeout >= utime_ts.tv_sec) {
280 /*
281 * If 'disableiftoolong' then just fall through
282 * so as to disable the pre-watchdog
283 */
284 if (disableiftoolong)
285 newtimeout = 0;
286 else
287 return EINVAL;
288 }
289
290 /* disable the pre-timeout */
291 if (newtimeout == 0) {
292 wd_pretimeout = 0;
293 callout_stop(&wd_pretimeo_handle);
294 return 0;
295 }
296
297 timeout_ticks = pow2ns_to_ticks(utime) - (hz*newtimeout);
298 #if 0
299 printf("wd_set_pretimeout: "
300 "newtimeout: %d, "
301 "utime: %d -> utime_ticks: %d, "
302 "hz*newtimeout: %d, "
303 "timeout_ticks: %d -> sec: %d\n",
304 newtimeout,
305 utime, pow2ns_to_ticks(utime),
306 hz*newtimeout,
307 timeout_ticks, timeout_ticks / hz);
308 #endif
309
310 /* We determined the value is sane, so reset the callout */
311 (void) callout_reset(&wd_pretimeo_handle,
312 timeout_ticks, wd_timeout_cb, "pre");
313 wd_pretimeout = newtimeout;
314 return 0;
315 }
316
317 static int
wd_ioctl(struct cdev * dev __unused,u_long cmd,caddr_t data,int flags __unused,struct thread * td)318 wd_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t data,
319 int flags __unused, struct thread *td)
320 {
321 u_int u;
322 time_t timeleft;
323 int error;
324
325 error = 0;
326
327 switch (cmd) {
328 case WDIOC_SETSOFT:
329 u = *(int *)data;
330 /* do nothing? */
331 if (u == wd_softtimer)
332 break;
333 /* If there is a pending timeout disallow this ioctl */
334 if (wd_last_u != 0) {
335 error = EINVAL;
336 break;
337 }
338 wd_softtimer = u;
339 break;
340 case WDIOC_SETSOFTTIMEOUTACT:
341 u = *(int *)data;
342 if (wd_valid_act(u)) {
343 wd_softtimeout_act = u;
344 } else {
345 error = EINVAL;
346 }
347 break;
348 case WDIOC_SETPRETIMEOUTACT:
349 u = *(int *)data;
350 if (wd_valid_act(u)) {
351 wd_pretimeout_act = u;
352 } else {
353 error = EINVAL;
354 }
355 break;
356 case WDIOC_GETPRETIMEOUT:
357 *(int *)data = (int)wd_pretimeout;
358 break;
359 case WDIOC_SETPRETIMEOUT:
360 error = wd_set_pretimeout(*(int *)data, false);
361 break;
362 case WDIOC_GETTIMELEFT:
363 error = wd_get_time_left(td, &timeleft);
364 if (error)
365 break;
366 *(int *)data = (int)timeleft;
367 break;
368 case WDIOC_SETTIMEOUT:
369 u = *(u_int *)data;
370 error = wdog_kern_pat(seconds_to_pow2ns(u));
371 break;
372 case WDIOC_GETTIMEOUT:
373 u = wdog_kern_last_timeout();
374 *(u_int *)data = u;
375 break;
376 case WDIOCPATPAT:
377 error = wd_ioctl_patpat(data);
378 break;
379 default:
380 error = ENOIOCTL;
381 break;
382 }
383 return (error);
384 }
385
386 /*
387 * Return the last timeout set, this is NOT the seconds from NOW until timeout,
388 * rather it is the amount of seconds passed to WDIOCPATPAT/WDIOC_SETTIMEOUT.
389 */
390 u_int
wdog_kern_last_timeout(void)391 wdog_kern_last_timeout(void)
392 {
393
394 return (wd_last_u);
395 }
396
397 static struct cdevsw wd_cdevsw = {
398 .d_version = D_VERSION,
399 .d_ioctl = wd_ioctl,
400 .d_name = "watchdog",
401 };
402
403 static int
watchdog_modevent(module_t mod __unused,int type,void * data __unused)404 watchdog_modevent(module_t mod __unused, int type, void *data __unused)
405 {
406 switch(type) {
407 case MOD_LOAD:
408 callout_init(&wd_pretimeo_handle, 1);
409 callout_init(&wd_softtimeo_handle, 1);
410 wd_dev = make_dev(&wd_cdevsw, 0,
411 UID_ROOT, GID_WHEEL, 0600, _PATH_WATCHDOG);
412 return 0;
413 case MOD_UNLOAD:
414 callout_stop(&wd_pretimeo_handle);
415 callout_stop(&wd_softtimeo_handle);
416 callout_drain(&wd_pretimeo_handle);
417 callout_drain(&wd_softtimeo_handle);
418 destroy_dev(wd_dev);
419 return 0;
420 case MOD_SHUTDOWN:
421 return 0;
422 default:
423 return EOPNOTSUPP;
424 }
425 }
426
427 DEV_MODULE(watchdog, watchdog_modevent, NULL);
428