xref: /dragonfly/sys/kern/kern_shutdown.c (revision a3127495)
1 /*-
2  * Copyright (c) 1986, 1988, 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
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  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)kern_shutdown.c	8.3 (Berkeley) 1/21/94
35  * $FreeBSD: src/sys/kern/kern_shutdown.c,v 1.72.2.12 2002/02/21 19:15:10 dillon Exp $
36  */
37 
38 #include "opt_ddb.h"
39 #include "opt_ddb_trace.h"
40 #include "opt_panic.h"
41 #include "use_gpio.h"
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/eventhandler.h>
46 #include <sys/buf.h>
47 #include <sys/disk.h>
48 #include <sys/diskslice.h>
49 #include <sys/reboot.h>
50 #include <sys/proc.h>
51 #include <sys/priv.h>
52 #include <sys/fcntl.h>		/* FREAD	*/
53 #include <sys/stat.h>		/* S_IFCHR	*/
54 #include <sys/vnode.h>
55 #include <sys/kernel.h>
56 #include <sys/kerneldump.h>
57 #include <sys/kthread.h>
58 #include <sys/malloc.h>
59 #include <sys/mount.h>
60 #include <sys/queue.h>
61 #include <sys/sysctl.h>
62 #include <sys/vkernel.h>
63 #include <sys/conf.h>
64 #include <sys/sysproto.h>
65 #include <sys/device.h>
66 #include <sys/cons.h>
67 #include <sys/kbio.h>
68 #include <sys/shm.h>
69 #include <sys/kern_syscall.h>
70 #include <vm/vm_map.h>
71 #include <vm/pmap.h>
72 
73 #include <sys/thread2.h>
74 #include <sys/buf2.h>
75 #include <sys/mplock2.h>
76 
77 #include <machine/cpu.h>
78 #include <machine/clock.h>
79 #include <machine/md_var.h>
80 #include <machine/smp.h>		/* smp_active_mask, cpuid */
81 #include <machine/vmparam.h>
82 #include <machine/thread.h>
83 
84 #include <sys/signalvar.h>
85 
86 #include <sys/wdog.h>
87 #include <dev/acpica/acpi_pvpanic/panic_notifier.h>
88 #include <dev/misc/gpio/gpio.h>
89 
90 #ifndef PANIC_REBOOT_WAIT_TIME
91 #define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
92 #endif
93 
94 /*
95  * Note that stdarg.h and the ANSI style va_start macro is used for both
96  * ANSI and traditional C compilers.  We use the machine version to stay
97  * within the confines of the kernel header files.
98  */
99 #include <machine/stdarg.h>
100 
101 #ifdef DDB
102 #include <ddb/ddb.h>
103 #ifdef DDB_UNATTENDED
104 int debugger_on_panic = 0;
105 #else
106 int debugger_on_panic = 1;
107 #endif
108 SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic, CTLFLAG_RW,
109 	&debugger_on_panic, 0, "Run debugger on kernel panic");
110 
111 #ifdef DDB_TRACE
112 int trace_on_panic = 1;
113 #else
114 int trace_on_panic = 0;
115 #endif
116 SYSCTL_INT(_debug, OID_AUTO, trace_on_panic, CTLFLAG_RW,
117 	&trace_on_panic, 0, "Print stack trace on kernel panic");
118 #endif
119 
120 static int sync_on_panic = 0;
121 SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RW,
122 	&sync_on_panic, 0, "Do a sync before rebooting from a panic");
123 
124 SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0, "Shutdown environment");
125 
126 /*
127  * Variable panicstr contains argument to first call to panic; used as flag
128  * to indicate that the kernel has already called panic.
129  */
130 const char *panicstr;
131 
132 int dumping;				/* system is dumping */
133 static struct dumperinfo dumper;	/* selected dumper */
134 
135 globaldata_t panic_cpu_gd;		/* which cpu took the panic */
136 struct lwkt_tokref panic_tokens[LWKT_MAXTOKENS];
137 int panic_tokens_count;
138 
139 int bootverbose = 0;			/* note: assignment to force non-bss */
140 SYSCTL_INT(_debug, OID_AUTO, bootverbose, CTLFLAG_RW,
141 	   &bootverbose, 0, "Verbose kernel messages");
142 
143 int cold = 1;				/* note: assignment to force non-bss */
144 int dumplo;				/* OBSOLETE - savecore compat */
145 u_int64_t dumplo64;
146 
147 static void boot (int) __dead2;
148 static int setdumpdev (cdev_t dev);
149 static void poweroff_wait (void *, int);
150 static void print_uptime (void);
151 static void shutdown_halt (void *junk, int howto);
152 static void shutdown_panic (void *junk, int howto);
153 static void shutdown_reset (void *junk, int howto);
154 static int shutdown_busycount1(struct buf *bp, void *info);
155 static int shutdown_busycount2(struct buf *bp, void *info);
156 static void shutdown_cleanup_proc(struct proc *p);
157 
158 /* register various local shutdown events */
159 static void
160 shutdown_conf(void *unused)
161 {
162 	EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL, SHUTDOWN_PRI_FIRST);
163 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL, SHUTDOWN_PRI_LAST + 100);
164 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL, SHUTDOWN_PRI_LAST + 100);
165 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL, SHUTDOWN_PRI_LAST + 200);
166 }
167 
168 SYSINIT(shutdown_conf, SI_BOOT2_MACHDEP, SI_ORDER_ANY, shutdown_conf, NULL);
169 
170 /* ARGSUSED */
171 
172 /*
173  * The system call that results in a reboot
174  *
175  * MPALMOSTSAFE
176  */
177 int
178 sys_reboot(struct reboot_args *uap)
179 {
180 	struct thread *td = curthread;
181 	int error;
182 
183 	if ((error = priv_check(td, PRIV_REBOOT)))
184 		return (error);
185 
186 	get_mplock();
187 	boot(uap->opt);
188 	rel_mplock();
189 	return (0);
190 }
191 
192 /*
193  * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
194  */
195 static int shutdown_howto = 0;
196 
197 void
198 shutdown_nice(int howto)
199 {
200 	shutdown_howto = howto;
201 
202 	/* Send a signal to init(8) and have it shutdown the world */
203 	if (initproc != NULL) {
204 		ksignal(initproc, SIGINT);
205 	} else {
206 		/* No init(8) running, so simply reboot */
207 		boot(RB_NOSYNC);
208 	}
209 	return;
210 }
211 static int	waittime = -1;
212 struct pcb	dumppcb;
213 struct thread	*dumpthread;
214 
215 static void
216 print_uptime(void)
217 {
218 	int f;
219 	struct timespec ts;
220 
221 	getnanouptime(&ts);
222 	kprintf("Uptime: ");
223 	f = 0;
224 	if (ts.tv_sec >= 86400) {
225 		kprintf("%ldd", ts.tv_sec / 86400);
226 		ts.tv_sec %= 86400;
227 		f = 1;
228 	}
229 	if (f || ts.tv_sec >= 3600) {
230 		kprintf("%ldh", ts.tv_sec / 3600);
231 		ts.tv_sec %= 3600;
232 		f = 1;
233 	}
234 	if (f || ts.tv_sec >= 60) {
235 		kprintf("%ldm", ts.tv_sec / 60);
236 		ts.tv_sec %= 60;
237 		f = 1;
238 	}
239 	kprintf("%lds\n", ts.tv_sec);
240 }
241 
242 /*
243  *  Go through the rigmarole of shutting down..
244  * this used to be in machdep.c but I'll be dammned if I could see
245  * anything machine dependant in it.
246  */
247 static void
248 boot(int howto)
249 {
250 	/*
251 	 * Get rid of any user scheduler baggage and then give
252 	 * us a high priority.
253 	 */
254 	if (curthread->td_release)
255 		curthread->td_release(curthread);
256 	lwkt_setpri_self(TDPRI_MAX);
257 
258 	/* collect extra flags that shutdown_nice might have set */
259 	howto |= shutdown_howto;
260 
261 	/*
262 	 * We really want to shutdown on the BSP.  Subsystems such as ACPI
263 	 * can't power-down the box otherwise.
264 	 */
265 	if (!CPUMASK_ISUP(smp_active_mask)) {
266 		kprintf("boot() called on cpu#%d\n", mycpu->gd_cpuid);
267 	}
268 	if (panicstr == NULL && mycpu->gd_cpuid != 0) {
269 		kprintf("Switching to cpu #0 for shutdown\n");
270 		lwkt_setcpu_self(globaldata_find(0));
271 	}
272 	/*
273 	 * Do any callouts that should be done BEFORE syncing the filesystems.
274 	 */
275 	EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
276 
277 	/*
278 	 * Try to get rid of any remaining FS references.  The calling
279 	 * process, proc0, and init may still hold references.  The
280 	 * VFS cache subsystem may still hold a root reference to root.
281 	 *
282 	 * XXX this needs work.  We really need to SIGSTOP all remaining
283 	 * processes in order to avoid blowups due to proc0's filesystem
284 	 * references going away.  For now just make sure that the init
285 	 * process is stopped.
286 	 */
287 	if (panicstr == NULL) {
288 		shutdown_cleanup_proc(curproc);
289 		shutdown_cleanup_proc(&proc0);
290 		if (initproc) {
291 			if (initproc != curproc) {
292 				ksignal(initproc, SIGSTOP);
293 				tsleep(boot, 0, "shutdn", hz / 20);
294 			}
295 			shutdown_cleanup_proc(initproc);
296 		}
297 		vfs_cache_setroot(NULL, NULL);
298 	}
299 
300 	/*
301 	 * Now sync filesystems
302 	 */
303 	if (!cold && (howto & RB_NOSYNC) == 0 && waittime < 0) {
304 		int iter, nbusy, pbusy;
305 		int zcount;
306 
307 		waittime = 0;
308 		zcount = 0;
309 		kprintf("\nsyncing disks... ");
310 
311 		sys_sync(NULL);
312 
313 		/*
314 		 * With soft updates, some buffers that are written will be
315 		 * remarked as dirty until other buffers are written.
316 		 *
317 		 * sys_sync() usually runs asynchronously, to give us a
318 		 * better chance of syncing the rest of the filesystems when
319 		 * one or more of them are stuck.
320 		 */
321 		for (iter = pbusy = 0; iter < 20 + zcount; iter++) {
322 			if (iter <= 10)
323 				nbusy = scan_all_buffers(shutdown_busycount1,
324 							 &iter);
325 			else
326 				nbusy = scan_all_buffers(shutdown_busycount2,
327 							 &iter);
328 			kprintf("%d ", nbusy);
329 			if (nbusy == 0) {
330 				if (++zcount == 3)
331 					break;
332 			} else {
333 				zcount = 0;
334 			}
335 
336 			/*
337 			 * There could be a lot to sync, only allow iter to
338 			 * proceed while there is progress.
339 			 */
340 			if (nbusy < pbusy) {
341 				if (iter > 10)
342 					iter = 10;
343 				else
344 					iter = 0;
345 			}
346 			pbusy = nbusy;
347 
348 			/*
349 			 * XXX:
350 			 * Process soft update work queue if buffers don't sync
351 			 * after 6 iterations by permitting the syncer to run.
352 			 */
353 			if (iter > 5)
354 				bio_ops_sync(NULL);
355 
356 			sys_sync(NULL);
357 			tsleep(boot, 0, "shutdn", hz * iter / 20 + 1);
358 		}
359 		kprintf("\n");
360 
361 		if (zcount < 3) {
362 			/*
363 			 * Failed to sync all blocks. Indicate this and don't
364 			 * unmount filesystems (thus forcing an fsck on reboot).
365 			 */
366 			kprintf("giving up on %d buffers\n", nbusy);
367 #ifdef DDB
368 			if (debugger_on_panic)
369 				Debugger("busy buffer problem");
370 #endif /* DDB */
371 			tsleep(boot, 0, "shutdn", hz * 5 + 1);
372 		} else {
373 			kprintf("done\n");
374 
375 			/*
376 			 * Unmount filesystems
377 			 */
378 			if (panicstr == NULL)
379 				vfs_unmountall();
380 		}
381 		tsleep(boot, 0, "shutdn", hz / 10 + 1);
382 	}
383 
384 	print_uptime();
385 
386 	/*
387 	 * Dump before doing post_sync shutdown ops
388 	 */
389 	crit_enter();
390 	if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold) {
391 		dumpsys();
392 	}
393 
394 	/*
395 	 * Ok, now do things that assume all filesystem activity has
396 	 * been completed.  This will also call the device shutdown
397 	 * methods.
398 	 */
399 	EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
400 
401 	/* Now that we're going to really halt the system... */
402 	EVENTHANDLER_INVOKE(shutdown_final, howto);
403 
404 	for(;;) ;	/* safety against shutdown_reset not working */
405 	/* NOTREACHED */
406 }
407 
408 /*
409  * Pass 1 - Figure out if there are any busy or dirty buffers still present.
410  *
411  *	We ignore TMPFS mounts in this pass.
412  */
413 static int
414 shutdown_busycount1(struct buf *bp, void *info __unused)
415 {
416 	struct vnode *vp;
417 
418 	if ((vp = bp->b_vp) != NULL && vp->v_tag == VT_TMPFS)
419 		return (0);
420 	if ((bp->b_flags & B_INVAL) == 0 && BUF_LOCKINUSE(bp))
421 		return(1);
422 	if ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI)
423 		return (1);
424 	return (0);
425 }
426 
427 /*
428  * Pass 2 - only run after pass 1 has completed or has given up
429  *
430  *	We ignore TMPFS, NFS, MFS, and SMBFS mounts in this pass.
431  */
432 static int
433 shutdown_busycount2(struct buf *bp, void *info)
434 {
435 	struct vnode *vp;
436 	int *iterp = info;
437 	const char *mpath;
438 
439 	/*
440 	 * Ignore tmpfs and nfs mounts
441 	 */
442 	if ((vp = bp->b_vp) != NULL) {
443 		if (vp->v_tag == VT_TMPFS)
444 			return (0);
445 		if (vp->v_tag == VT_NFS)
446 			return (0);
447 		if (vp->v_tag == VT_MFS)
448 			return (0);
449 		if (vp->v_tag == VT_SMBFS)
450 			return (0);
451 	}
452 
453 	/*
454 	 * Only count buffers stuck on I/O, ignore everything else
455 	 */
456 	if (((bp->b_flags & B_INVAL) == 0 && BUF_LOCKINUSE(bp)) ||
457 	    ((bp->b_flags & (B_DELWRI|B_INVAL)) == B_DELWRI)) {
458 		/*
459 		 * Only count buffers undergoing write I/O
460 		 * on the related vnode.
461 		 */
462 		if (bp->b_vp == NULL ||
463 		    bio_track_active(&bp->b_vp->v_track_write) == 0) {
464 			return (0);
465 		}
466 		if (*iterp > 15) {
467 			mpath = "?";
468 			if (bp->b_vp->v_mount)
469 				mpath = bp->b_vp->v_mount->mnt_stat.f_mntonname;
470 
471 			kprintf("%p on %s, flags:%08x, loffset:%jd, "
472 				"doffset:%jd\n",
473 				bp,
474 				mpath,
475 				bp->b_flags,
476 				(intmax_t)bp->b_loffset,
477 				(intmax_t)bp->b_bio2.bio_offset);
478 		}
479 		return(1);
480 	}
481 	return(0);
482 }
483 
484 /*
485  * If the shutdown was a clean halt, behave accordingly.
486  */
487 static void
488 shutdown_halt(void *junk, int howto)
489 {
490 	if (howto & RB_HALT) {
491 		kprintf("\n");
492 		kprintf("The operating system has halted.\n");
493 #ifdef _KERNEL_VIRTUAL
494 		cpu_halt();
495 #else
496 		kprintf("Please press any key to reboot.\n\n");
497 		switch (cngetc()) {
498 		case -1:		/* No console, just die */
499 			cpu_halt();
500 			/* NOTREACHED */
501 		default:
502 			howto &= ~RB_HALT;
503 			break;
504 		}
505 #endif
506 	}
507 }
508 
509 /*
510  * Check to see if the system paniced, pause and then reboot
511  * according to the specified delay.
512  */
513 static void
514 shutdown_panic(void *junk, int howto)
515 {
516 	int loop;
517 	int c;
518 
519 	if (howto & RB_DUMP) {
520 		if (PANIC_REBOOT_WAIT_TIME != 0) {
521 			if (PANIC_REBOOT_WAIT_TIME != -1) {
522 				kprintf("Automatic reboot in %d seconds - "
523 				       "press a key on the console to abort\n",
524 					PANIC_REBOOT_WAIT_TIME);
525 				for (loop = PANIC_REBOOT_WAIT_TIME * 10;
526 				     loop > 0; --loop) {
527 					DELAY(1000 * 100); /* 1/10th second */
528 					/* Did user type a key? */
529 					c = cncheckc();
530 					if (c != -1 && c != NOKEY)
531 						break;
532 				}
533 				if (!loop)
534 					return;
535 			}
536 		} else { /* zero time specified - reboot NOW */
537 			return;
538 		}
539 		kprintf("--> Press a key on the console to reboot,\n");
540 		kprintf("--> or switch off the system now.\n");
541 		cngetc();
542 	}
543 }
544 
545 /*
546  * Everything done, now reset
547  */
548 static void
549 shutdown_reset(void *junk, int howto)
550 {
551 	kprintf("Rebooting...\n");
552 	DELAY(1000000);	/* wait 1 sec for kprintf's to complete and be read */
553 	/* cpu_boot(howto); */ /* doesn't do anything at the moment */
554 	cpu_reset();
555 	/* NOTREACHED */ /* assuming reset worked */
556 }
557 
558 /*
559  * Try to remove FS references in the specified process.  This function
560  * is used during shutdown
561  */
562 static
563 void
564 shutdown_cleanup_proc(struct proc *p)
565 {
566 	struct filedesc *fdp;
567 	struct vmspace *vm;
568 
569 	if (p == NULL)
570 		return;
571 	if ((fdp = p->p_fd) != NULL) {
572 		kern_closefrom(0);
573 		if (fdp->fd_cdir) {
574 			cache_drop(&fdp->fd_ncdir);
575 			vrele(fdp->fd_cdir);
576 			fdp->fd_cdir = NULL;
577 		}
578 		if (fdp->fd_rdir) {
579 			cache_drop(&fdp->fd_nrdir);
580 			vrele(fdp->fd_rdir);
581 			fdp->fd_rdir = NULL;
582 		}
583 		if (fdp->fd_jdir) {
584 			cache_drop(&fdp->fd_njdir);
585 			vrele(fdp->fd_jdir);
586 			fdp->fd_jdir = NULL;
587 		}
588 	}
589 	if (p->p_vkernel)
590 		vkernel_exit(p);
591 	if (p->p_textvp) {
592 		vrele(p->p_textvp);
593 		p->p_textvp = NULL;
594 	}
595 	vm = p->p_vmspace;
596 	if (vm != NULL) {
597 		pmap_remove_pages(vmspace_pmap(vm),
598 				  VM_MIN_USER_ADDRESS,
599 				  VM_MAX_USER_ADDRESS);
600 		vm_map_remove(&vm->vm_map,
601 			      VM_MIN_USER_ADDRESS,
602 			      VM_MAX_USER_ADDRESS);
603 	}
604 }
605 
606 /*
607  * Magic number for savecore
608  *
609  * exported (symorder) and used at least by savecore(8)
610  *
611  * Mark it as used so that gcc doesn't optimize it away.
612  */
613 __attribute__((__used__))
614 	static u_long const dumpmag = 0x8fca0101UL;
615 
616 __attribute__((__used__))
617 	static int	dumpsize = 0;		/* also for savecore */
618 
619 static int	dodump = 1;
620 
621 SYSCTL_INT(_machdep, OID_AUTO, do_dump, CTLFLAG_RW, &dodump, 0,
622     "Try to perform coredump on kernel panic");
623 
624 void
625 mkdumpheader(struct kerneldumpheader *kdh, char *magic, uint32_t archver,
626     uint64_t dumplen, uint32_t blksz)
627 {
628 	bzero(kdh, sizeof(*kdh));
629 	strncpy(kdh->magic, magic, sizeof(kdh->magic));
630 	strncpy(kdh->architecture, MACHINE_ARCH, sizeof(kdh->architecture));
631 	kdh->version = htod32(KERNELDUMPVERSION);
632 	kdh->architectureversion = htod32(archver);
633 	kdh->dumplength = htod64(dumplen);
634 	kdh->dumptime = htod64(time_second);
635 	kdh->blocksize = htod32(blksz);
636 	strncpy(kdh->hostname, hostname, sizeof(kdh->hostname));
637 	strncpy(kdh->versionstring, version, sizeof(kdh->versionstring));
638 	if (panicstr != NULL)
639 		strncpy(kdh->panicstring, panicstr, sizeof(kdh->panicstring));
640 	kdh->parity = kerneldump_parity(kdh);
641 }
642 
643 static int
644 setdumpdev(cdev_t dev)
645 {
646 	int error;
647 	int doopen;
648 
649 	if (dev == NULL) {
650 		disk_dumpconf(NULL, 0/*off*/);
651 		dumpdev = NULL;
652 		return (0);
653 	}
654 
655 	/*
656 	 * We have to open the device before we can perform ioctls on it,
657 	 * or the slice/label data may not be present.  Device opens are
658 	 * usually tracked by specfs, but the dump device can be set in
659 	 * early boot and may not be open so this is somewhat of a hack.
660 	 */
661 	doopen = (dev->si_sysref.refcnt == 1);
662 	if (doopen) {
663 		error = dev_dopen(dev, FREAD, S_IFCHR, proc0.p_ucred, NULL);
664 		if (error)
665 			return (error);
666 	}
667 	error = disk_dumpconf(dev, 1/*on*/);
668 	if (error == 0)
669 		dumpdev = dev;
670 
671 	return error;
672 }
673 
674 /* ARGSUSED */
675 static void dump_conf (void *dummy);
676 static void
677 dump_conf(void *dummy)
678 {
679 	char *path;
680 	cdev_t dev;
681 	int _dummy;
682 
683 	path = kmalloc(MNAMELEN, M_TEMP, M_WAITOK);
684 	if (TUNABLE_STR_FETCH("dumpdev", path, MNAMELEN) != 0) {
685 		/*
686 		 * Make sure all disk devices created so far have also been
687 		 * probed, and also make sure that the newly created device
688 		 * nodes for probed disks are ready, too.
689 		 *
690 		 * XXX - Delay an additional 2 seconds to help drivers which
691 		 *	 pickup devices asynchronously and are not caught by
692 		 *	 CAM's initial probe.
693 		 */
694 		sync_devs();
695 		tsleep(&_dummy, 0, "syncer", hz*2);
696 
697 		dev = kgetdiskbyname(path);
698 		if (dev != NULL)
699 			dumpdev = dev;
700 	}
701 	kfree(path, M_TEMP);
702 	if (setdumpdev(dumpdev) != 0)
703 		dumpdev = NULL;
704 }
705 
706 SYSINIT(dump_conf, SI_SUB_DUMP_CONF, SI_ORDER_FIRST, dump_conf, NULL);
707 
708 static int
709 sysctl_kern_dumpdev(SYSCTL_HANDLER_ARGS)
710 {
711 	int error;
712 	udev_t ndumpdev;
713 
714 	ndumpdev = dev2udev(dumpdev);
715 	error = sysctl_handle_opaque(oidp, &ndumpdev, sizeof ndumpdev, req);
716 	if (error == 0 && req->newptr != NULL)
717 		error = setdumpdev(udev2dev(ndumpdev, 0));
718 	return (error);
719 }
720 
721 SYSCTL_PROC(_kern, KERN_DUMPDEV, dumpdev, CTLTYPE_OPAQUE|CTLFLAG_RW,
722 	0, sizeof dumpdev, sysctl_kern_dumpdev, "T,udev_t", "");
723 
724 static struct panicerinfo *panic_notifier;
725 
726 int
727 set_panic_notifier(struct panicerinfo *info)
728 {
729 	if (info == NULL)
730 		panic_notifier = NULL;
731 	else if (panic_notifier != NULL)
732 		return 1;
733 	else
734 		panic_notifier = info;
735 
736 	return 0;
737 }
738 
739 /*
740  * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
741  * and then reboots.  If we are called twice, then we avoid trying to sync
742  * the disks as this often leads to recursive panics.
743  */
744 void
745 panic(const char *fmt, ...)
746 {
747 	int bootopt, newpanic;
748 	globaldata_t gd = mycpu;
749 	thread_t td = gd->gd_curthread;
750 	__va_list ap;
751 	static char buf[256];
752 
753 	/*
754 	 * If a panic occurs on multiple cpus before the first is able to
755 	 * halt the other cpus, only one cpu is allowed to take the panic.
756 	 * Attempt to be verbose about this situation but if the kprintf()
757 	 * itself panics don't let us overrun the kernel stack.
758 	 *
759 	 * Be very nasty about descheduling our thread at the lowest
760 	 * level possible in an attempt to freeze the thread without
761 	 * inducing further panics.
762 	 *
763 	 * Bumping gd_trap_nesting_level will also bypass assertions in
764 	 * lwkt_switch() and allow us to switch away even if we are a
765 	 * FAST interrupt or IPI.
766 	 *
767 	 * The setting of panic_cpu_gd also determines how kprintf()
768 	 * spin-locks itself.  DDB can set panic_cpu_gd as well.
769 	 */
770 	for (;;) {
771 		globaldata_t xgd = panic_cpu_gd;
772 
773 		/*
774 		 * Someone else got the panic cpu
775 		 */
776 		if (xgd && xgd != gd) {
777 			crit_enter();
778 			++mycpu->gd_trap_nesting_level;
779 			if (mycpu->gd_trap_nesting_level < 25) {
780 				kprintf("SECONDARY PANIC ON CPU %d THREAD %p\n",
781 					mycpu->gd_cpuid, td);
782 			}
783 			td->td_release = NULL;	/* be a grinch */
784 			for (;;) {
785 				lwkt_deschedule_self(td);
786 				lwkt_switch();
787 			}
788 			/* NOT REACHED */
789 			/* --mycpu->gd_trap_nesting_level */
790 			/* crit_exit() */
791 		}
792 
793 		/*
794 		 * Reentrant panic
795 		 */
796 		if (xgd && xgd == gd)
797 			break;
798 
799 		/*
800 		 * We got it
801 		 */
802 		if (atomic_cmpset_ptr(&panic_cpu_gd, NULL, gd))
803 			break;
804 	}
805 	/*
806 	 * Try to get the system into a working state.  Save information
807 	 * we are about to destroy.
808 	 */
809 	kvcreinitspin();
810 	if (panicstr == NULL) {
811 		bcopy(td->td_toks_array, panic_tokens, sizeof(panic_tokens));
812 		panic_tokens_count = td->td_toks_stop - &td->td_toks_base;
813 	}
814 	lwkt_relalltokens(td);
815 	td->td_toks_stop = &td->td_toks_base;
816 	if (gd->gd_spinlocks)
817 		kprintf("panic with %d spinlocks held\n", gd->gd_spinlocks);
818 	gd->gd_spinlocks = 0;
819 
820 	/*
821 	 * Setup
822 	 */
823 	bootopt = RB_AUTOBOOT | RB_DUMP;
824 	if (sync_on_panic == 0)
825 		bootopt |= RB_NOSYNC;
826 	newpanic = 0;
827 	if (panicstr) {
828 		bootopt |= RB_NOSYNC;
829 	} else {
830 		panicstr = fmt;
831 		newpanic = 1;
832 	}
833 
834 	/*
835 	 * Format the panic string.
836 	 */
837 	__va_start(ap, fmt);
838 	kvsnprintf(buf, sizeof(buf), fmt, ap);
839 	if (panicstr == fmt)
840 		panicstr = buf;
841 	__va_end(ap);
842 	if (panic_notifier != NULL)
843 		panic_notifier->notifier(panic_notifier->arg);
844 	kprintf("panic: %s\n", buf);
845 	/* two separate prints in case of an unmapped page and trap */
846 	kprintf("cpuid = %d\n", mycpu->gd_cpuid);
847 
848 #if (NGPIO > 0) && defined(ERROR_LED_ON_PANIC)
849 	led_switch("error", 1);
850 #endif
851 
852 #if defined(WDOG_DISABLE_ON_PANIC)
853 	wdog_disable();
854 #endif
855 
856 	/*
857 	 * Make sure kgdb knows who we are, there won't be a stoppcbs[]
858 	 * entry since our cpu wasn't stopped.
859 	 */
860 	savectx(&dumppcb);
861 	dumpthread = curthread;
862 
863 	/*
864 	 * Enter the debugger or fall through & dump.  Entering the
865 	 * debugger will stop cpus.  If not entering the debugger stop
866 	 * cpus here.
867 	 *
868 	 * Limit the trace history to leave more panic data on a
869 	 * potentially row-limited console.
870 	 */
871 
872 #if defined(DDB)
873 	if (newpanic && trace_on_panic)
874 		print_backtrace(6);
875 	if (debugger_on_panic)
876 		Debugger("panic");
877 	else
878 #endif
879 	if (newpanic)
880 		stop_cpus(mycpu->gd_other_cpus);
881 	boot(bootopt);
882 }
883 
884 /*
885  * Support for poweroff delay.
886  */
887 #ifndef POWEROFF_DELAY
888 # define POWEROFF_DELAY 5000
889 #endif
890 static int poweroff_delay = POWEROFF_DELAY;
891 
892 SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
893 	&poweroff_delay, 0, "");
894 
895 static void
896 poweroff_wait(void *junk, int howto)
897 {
898 	if(!(howto & RB_POWEROFF) || poweroff_delay <= 0)
899 		return;
900 	DELAY(poweroff_delay * 1000);
901 }
902 
903 /*
904  * Some system processes (e.g. syncer) need to be stopped at appropriate
905  * points in their main loops prior to a system shutdown, so that they
906  * won't interfere with the shutdown process (e.g. by holding a disk buf
907  * to cause sync to fail).  For each of these system processes, register
908  * shutdown_kproc() as a handler for one of shutdown events.
909  */
910 static int kproc_shutdown_wait = 60;
911 SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
912     &kproc_shutdown_wait, 0, "");
913 
914 void
915 shutdown_kproc(void *arg, int howto)
916 {
917 	struct thread *td;
918 	struct proc *p;
919 	int error;
920 
921 	if (panicstr)
922 		return;
923 
924 	td = (struct thread *)arg;
925 	if ((p = td->td_proc) != NULL) {
926 	    kprintf("Waiting (max %d seconds) for system process `%s' to stop...",
927 		kproc_shutdown_wait, p->p_comm);
928 	} else {
929 	    kprintf("Waiting (max %d seconds) for system thread %s to stop...",
930 		kproc_shutdown_wait, td->td_comm);
931 	}
932 	error = suspend_kproc(td, kproc_shutdown_wait * hz);
933 
934 	if (error == EWOULDBLOCK)
935 		kprintf("timed out\n");
936 	else
937 		kprintf("stopped\n");
938 }
939 
940 /* Registration of dumpers */
941 int
942 set_dumper(struct dumperinfo *di)
943 {
944 	if (di == NULL) {
945 		bzero(&dumper, sizeof(dumper));
946 		return 0;
947 	}
948 
949 	if (dumper.dumper != NULL)
950 		return (EBUSY);
951 
952 	dumper = *di;
953 	return 0;
954 }
955 
956 void
957 dumpsys(void)
958 {
959 #if defined (_KERNEL_VIRTUAL)
960 	/* vkernels don't support dumps */
961 	kprintf("vkernels don't support dumps\n");
962 	return;
963 #endif
964 	/*
965 	 * If there is a dumper registered and we aren't dumping already, call
966 	 * the machine dependent dumpsys (md_dumpsys) to do the hard work.
967 	 *
968 	 * XXX: while right now the md_dumpsys() of x86 and x86_64 could be
969 	 *      factored out completely into here, I rather keep them machine
970 	 *      dependent in case we ever add a platform which does not share
971 	 *      the same dumpsys() code, such as arm.
972 	 */
973 	if (dumper.dumper != NULL && !dumping) {
974 		dumping++;
975 		md_dumpsys(&dumper);
976 	}
977 }
978 
979 int dump_stop_usertds = 0;
980 
981 static
982 void
983 need_user_resched_remote(void *dummy)
984 {
985 	need_user_resched();
986 }
987 
988 void
989 dump_reactivate_cpus(void)
990 {
991 	globaldata_t gd;
992 	int cpu, seq;
993 
994 	dump_stop_usertds = 1;
995 
996 	need_user_resched();
997 
998 	for (cpu = 0; cpu < ncpus; cpu++) {
999 		gd = globaldata_find(cpu);
1000 		seq = lwkt_send_ipiq(gd, need_user_resched_remote, NULL);
1001 		lwkt_wait_ipiq(gd, seq);
1002 	}
1003 
1004 	restart_cpus(stopped_cpus);
1005 }
1006