sys/kern/kern_shutdown.c

   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. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  *      @(#)kern_shutdown.c     8.3 (Berkeley) 1/21/94
  39  * $FreeBSD: src/sys/kern/kern_shutdown.c,v 1.72.2.12 2002/02/21 19:15:10 dillon Exp $
  40  * $DragonFly: src/sys/kern/kern_shutdown.c,v 1.45 2006/12/24 00:47:54 swildner Exp $
  41  */
  42
  43 #include "opt_ddb.h"
  44 #include "opt_ddb_trace.h"
  45 #include "opt_hw_wdog.h"
  46 #include "opt_panic.h"
  47 #include "opt_show_busybufs.h"
  48
  49 #include <sys/param.h>
  50 #include <sys/systm.h>
  51 #include <sys/eventhandler.h>
  52 #include <sys/buf.h>
  53 #include <sys/disklabel.h>
  54 #include <sys/reboot.h>
  55 #include <sys/proc.h>
  56 #include <sys/vnode.h>
  57 #include <sys/kernel.h>
  58 #include <sys/kthread.h>
  59 #include <sys/malloc.h>
  60 #include <sys/mount.h>
  61 #include <sys/queue.h>
  62 #include <sys/sysctl.h>
  63 #include <sys/vkernel.h>
  64 #include <sys/conf.h>
  65 #include <sys/sysproto.h>
  66 #include <sys/device.h>
  67 #include <sys/cons.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
  76 #include <machine/pcb.h>
  77 #include <machine/clock.h>
  78 #include <machine/md_var.h>
  79 #include <machine/smp.h>                /* smp_active_mask, cpuid */
  80
  81 #include <sys/signalvar.h>
  82
  83 #ifndef PANIC_REBOOT_WAIT_TIME
  84 #define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
  85 #endif
  86
  87 /*
  88  * Note that stdarg.h and the ANSI style va_start macro is used for both
  89  * ANSI and traditional C compilers.  We use the machine version to stay
  90  * within the confines of the kernel header files.
  91  */
  92 #include <machine/stdarg.h>
  93
  94 #ifdef DDB
  95 #ifdef DDB_UNATTENDED
  96 int debugger_on_panic = 0;
  97 #else
  98 int debugger_on_panic = 1;
  99 #endif
 100 SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic, CTLFLAG_RW,
 101         &debugger_on_panic, 0, "Run debugger on kernel panic");
 102
 103 extern void db_print_backtrace(void);
 104
 105 #ifdef DDB_TRACE
 106 int trace_on_panic = 1;
 107 #else
 108 int trace_on_panic = 0;
 109 #endif
 110 SYSCTL_INT(_debug, OID_AUTO, trace_on_panic, CTLFLAG_RW,
 111         &trace_on_panic, 0, "Print stack trace on kernel panic");
 112 #endif
 113
 114 static int sync_on_panic = 1;
 115 SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RW,
 116         &sync_on_panic, 0, "Do a sync before rebooting from a panic");
 117
 118 SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0, "Shutdown environment");
 119
 120 #ifdef  HW_WDOG
 121 /*
 122  * If there is a hardware watchdog, point this at the function needed to
 123  * hold it off.
 124  * It's needed when the kernel needs to do some lengthy operations.
 125  * e.g. in wd.c when dumping core.. It's most annoying to have
 126  * your precious core-dump only half written because the wdog kicked in.
 127  */
 128 watchdog_tickle_fn wdog_tickler = NULL;
 129 #endif  /* HW_WDOG */
 130
 131 /*
 132  * Variable panicstr contains argument to first call to panic; used as flag
 133  * to indicate that the kernel has already called panic.
 134  */
 135 const char *panicstr;
 136
 137 int dumping;                            /* system is dumping */
 138 #ifdef SMP
 139 u_int panic_cpu_interlock;              /* panic interlock */
 140 globaldata_t panic_cpu_gd;              /* which cpu took the panic */
 141 #endif
 142
 143 int bootverbose = 0;                    /* note: assignment to force non-bss */
 144 int cold = 1;                           /* note: assignment to force non-bss */
 145
 146 static void boot (int) __dead2;
 147 static void dumpsys (void);
 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_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL)
 169
 170 /* ARGSUSED */
 171
 172 /*
 173  * The system call that results in a reboot
 174  */
 175 int
 176 sys_reboot(struct reboot_args *uap)
 177 {
 178         struct thread *td = curthread;
 179         int error;
 180
 181         if ((error = suser(td)))
 182                 return (error);
 183
 184         boot(uap->opt);
 185         return (0);
 186 }
 187
 188 /*
 189  * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
 190  */
 191 static int shutdown_howto = 0;
 192
 193 void
 194 shutdown_nice(int howto)
 195 {
 196         shutdown_howto = howto;
 197
 198         /* Send a signal to init(8) and have it shutdown the world */
 199         if (initproc != NULL) {
 200                 ksignal(initproc, SIGINT);
 201         } else {
 202                 /* No init(8) running, so simply reboot */
 203                 boot(RB_NOSYNC);
 204         }
 205         return;
 206 }
 207 static int      waittime = -1;
 208 static struct thread *dumpthread;
 209 static struct pcb dumppcb;
 210
 211 static void
 212 print_uptime(void)
 213 {
 214         int f;
 215         struct timespec ts;
 216
 217         getnanouptime(&ts);
 218         kprintf("Uptime: ");
 219         f = 0;
 220         if (ts.tv_sec >= 86400) {
 221                 kprintf("%ldd", ts.tv_sec / 86400);
 222                 ts.tv_sec %= 86400;
 223                 f = 1;
 224         }
 225         if (f || ts.tv_sec >= 3600) {
 226                 kprintf("%ldh", ts.tv_sec / 3600);
 227                 ts.tv_sec %= 3600;
 228                 f = 1;
 229         }
 230         if (f || ts.tv_sec >= 60) {
 231                 kprintf("%ldm", ts.tv_sec / 60);
 232                 ts.tv_sec %= 60;
 233                 f = 1;
 234         }
 235         kprintf("%lds\n", ts.tv_sec);
 236 }
 237
 238 /*
 239  *  Go through the rigmarole of shutting down..
 240  * this used to be in machdep.c but I'll be dammned if I could see
 241  * anything machine dependant in it.
 242  */
 243 static void
 244 boot(int howto)
 245 {
 246         /*
 247          * Get rid of any user scheduler baggage and then give
 248          * us a high priority.
 249          */
 250         if (curthread->td_release)
 251                 curthread->td_release(curthread);
 252         lwkt_setpri_self(TDPRI_MAX);
 253
 254         /* collect extra flags that shutdown_nice might have set */
 255         howto |= shutdown_howto;
 256
 257 #ifdef SMP
 258         /*
 259          * We really want to shutdown on the BSP.  Subsystems such as ACPI
 260          * can't power-down the box otherwise.
 261          */
 262         if (smp_active_mask > 1) {
 263                 kprintf("boot() called on cpu#%d\n", mycpu->gd_cpuid);
 264         }
 265         if (panicstr == NULL && mycpu->gd_cpuid != 0) {
 266                 kprintf("Switching to cpu #0 for shutdown\n");
 267                 lwkt_setcpu_self(globaldata_find(0));
 268         }
 269 #endif
 270         /*
 271          * Do any callouts that should be done BEFORE syncing the filesystems.
 272          */
 273         EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
 274
 275         /*
 276          * Try to get rid of any remaining FS references.  The calling
 277          * process, proc0, and init may still hold references.  The
 278          * VFS cache subsystem may still hold a root reference to root.
 279          */
 280         if (panicstr == NULL) {
 281                 shutdown_cleanup_proc(curproc);
 282                 shutdown_cleanup_proc(&proc0);
 283                 if (initproc)
 284                         shutdown_cleanup_proc(initproc);
 285                 vfs_cache_setroot(NULL, NULL);
 286         }
 287
 288         /*
 289          * Now sync filesystems
 290          */
 291         if (!cold && (howto & RB_NOSYNC) == 0 && waittime < 0) {
 292                 int iter, nbusy, pbusy;
 293
 294                 waittime = 0;
 295                 kprintf("\nsyncing disks... ");
 296
 297                 sys_sync(NULL); /* YYY was sync(&proc0, NULL). why proc0 ? */
 298
 299                 /*
 300                  * With soft updates, some buffers that are
 301                  * written will be remarked as dirty until other
 302                  * buffers are written.
 303                  */
 304                 for (iter = pbusy = 0; iter < 20; iter++) {
 305                         nbusy = scan_all_buffers(shutdown_busycount1, NULL);
 306                         if (nbusy == 0)
 307                                 break;
 308                         kprintf("%d ", nbusy);
 309                         if (nbusy < pbusy)
 310                                 iter = 0;
 311                         pbusy = nbusy;
 312                         /*
 313                          * XXX:
 314                          * Process soft update work queue if buffers don't sync
 315                          * after 6 iterations by permitting the syncer to run.
 316                          */
 317                         if (iter > 5 && bioops.io_sync)
 318                                 (*bioops.io_sync)(NULL);
 319                         sys_sync(NULL); /* YYY was sync(&proc0, NULL). why proc0 ? */
 320                         tsleep(boot, 0, "shutdn", hz * iter / 20 + 1);
 321                 }
 322                 kprintf("\n");
 323                 /*
 324                  * Count only busy local buffers to prevent forcing
 325                  * a fsck if we're just a client of a wedged NFS server
 326                  */
 327                 nbusy = scan_all_buffers(shutdown_busycount2, NULL);
 328                 if (nbusy) {
 329                         /*
 330                          * Failed to sync all blocks. Indicate this and don't
 331                          * unmount filesystems (thus forcing an fsck on reboot).
 332                          */
 333                         kprintf("giving up on %d buffers\n", nbusy);
 334 #ifdef DDB
 335                         Debugger("busy buffer problem");
 336 #endif /* DDB */
 337                         tsleep(boot, 0, "shutdn", hz * 5 + 1);
 338                 } else {
 339                         kprintf("done\n");
 340                         /*
 341                          * Unmount filesystems
 342                          */
 343                         if (panicstr == NULL)
 344                                 vfs_unmountall();
 345                 }
 346                 tsleep(boot, 0, "shutdn", hz / 10 + 1);
 347         }
 348
 349         print_uptime();
 350
 351         /*
 352          * Ok, now do things that assume all filesystem activity has
 353          * been completed.
 354          */
 355         EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
 356         crit_enter();
 357         if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold)
 358                 dumpsys();
 359
 360         /* Now that we're going to really halt the system... */
 361         EVENTHANDLER_INVOKE(shutdown_final, howto);
 362
 363         for(;;) ;       /* safety against shutdown_reset not working */
 364         /* NOTREACHED */
 365 }
 366
 367 static int
 368 shutdown_busycount1(struct buf *bp, void *info)
 369 {
 370         if ((bp->b_flags & B_INVAL) == 0 && BUF_REFCNT(bp) > 0)
 371                 return(1);
 372         if ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI)
 373                 return (1);
 374         return (0);
 375 }
 376
 377 static int
 378 shutdown_busycount2(struct buf *bp, void *info)
 379 {
 380         if (((bp->b_flags & B_INVAL) == 0 && BUF_REFCNT(bp)) ||
 381             ((bp->b_flags & (B_DELWRI|B_INVAL)) == B_DELWRI)) {
 382                 /*
 383                  * Only count buffers undergoing write I/O
 384                  * on the related vnode.
 385                  */
 386                 if (bp->b_vp == NULL ||
 387                     bp->b_vp->v_track_write.bk_active == 0) {
 388                         return (0);
 389                 }
 390 #if defined(SHOW_BUSYBUFS) || defined(DIAGNOSTIC)
 391                 kprintf(
 392             "%p dev:?, flags:%08x, loffset:%lld, doffset:%lld\n",
 393                     bp,
 394                     bp->b_flags, bp->b_loffset,
 395                     bp->b_bio2.bio_offset);
 396 #endif
 397                 return(1);
 398         }
 399         return(0);
 400 }
 401
 402 /*
 403  * If the shutdown was a clean halt, behave accordingly.
 404  */
 405 static void
 406 shutdown_halt(void *junk, int howto)
 407 {
 408         if (howto & RB_HALT) {
 409                 kprintf("\n");
 410                 kprintf("The operating system has halted.\n");
 411                 kprintf("Please press any key to reboot.\n\n");
 412                 switch (cngetc()) {
 413                 case -1:                /* No console, just die */
 414                         cpu_halt();
 415                         /* NOTREACHED */
 416                 default:
 417                         howto &= ~RB_HALT;
 418                         break;
 419                 }
 420         }
 421 }
 422
 423 /*
 424  * Check to see if the system paniced, pause and then reboot
 425  * according to the specified delay.
 426  */
 427 static void
 428 shutdown_panic(void *junk, int howto)
 429 {
 430         int loop;
 431
 432         if (howto & RB_DUMP) {
 433                 if (PANIC_REBOOT_WAIT_TIME != 0) {
 434                         if (PANIC_REBOOT_WAIT_TIME != -1) {
 435                                 kprintf("Automatic reboot in %d seconds - "
 436                                        "press a key on the console to abort\n",
 437                                         PANIC_REBOOT_WAIT_TIME);
 438                                 for (loop = PANIC_REBOOT_WAIT_TIME * 10;
 439                                      loop > 0; --loop) {
 440                                         DELAY(1000 * 100); /* 1/10th second */
 441                                         /* Did user type a key? */
 442                                         if (cncheckc() != -1)
 443                                                 break;
 444                                 }
 445                                 if (!loop)
 446                                         return;
 447                         }
 448                 } else { /* zero time specified - reboot NOW */
 449                         return;
 450                 }
 451                 kprintf("--> Press a key on the console to reboot,\n");
 452                 kprintf("--> or switch off the system now.\n");
 453                 cngetc();
 454         }
 455 }
 456
 457 /*
 458  * Everything done, now reset
 459  */
 460 static void
 461 shutdown_reset(void *junk, int howto)
 462 {
 463         kprintf("Rebooting...\n");
 464         DELAY(1000000); /* wait 1 sec for kprintf's to complete and be read */
 465         /* cpu_boot(howto); */ /* doesn't do anything at the moment */
 466         cpu_reset();
 467         /* NOTREACHED */ /* assuming reset worked */
 468 }
 469
 470 /*
 471  * Try to remove FS references in the specified process.  This function
 472  * is used during shutdown
 473  */
 474 static
 475 void
 476 shutdown_cleanup_proc(struct proc *p)
 477 {
 478         struct filedesc *fdp;
 479         struct vmspace *vm;
 480
 481         if (p == NULL)
 482                 return;
 483         if ((fdp = p->p_fd) != NULL) {
 484                 kern_closefrom(0);
 485                 if (fdp->fd_cdir) {
 486                         cache_drop(&fdp->fd_ncdir);
 487                         vrele(fdp->fd_cdir);
 488                         fdp->fd_cdir = NULL;
 489                 }
 490                 if (fdp->fd_rdir) {
 491                         cache_drop(&fdp->fd_nrdir);
 492                         vrele(fdp->fd_rdir);
 493                         fdp->fd_rdir = NULL;
 494                 }
 495                 if (fdp->fd_jdir) {
 496                         cache_drop(&fdp->fd_njdir);
 497                         vrele(fdp->fd_jdir);
 498                         fdp->fd_jdir = NULL;
 499                 }
 500         }
 501         if (p->p_vkernel)
 502                 vkernel_exit(p);
 503         if (p->p_textvp) {
 504                 vrele(p->p_textvp);
 505                 p->p_textvp = NULL;
 506         }
 507         vm = p->p_vmspace;
 508         if (vm != NULL) {
 509                 pmap_remove_pages(vmspace_pmap(vm),
 510                                   VM_MIN_USER_ADDRESS,
 511                                   VM_MAX_USER_ADDRESS);
 512                 vm_map_remove(&vm->vm_map,
 513                               VM_MIN_USER_ADDRESS,
 514                               VM_MAX_USER_ADDRESS);
 515         }
 516 }
 517
 518 /*
 519  * Magic number for savecore
 520  *
 521  * exported (symorder) and used at least by savecore(8)
 522  *
 523  */
 524 static u_long const     dumpmag = 0x8fca0101UL;
 525
 526 static int      dumpsize = 0;           /* also for savecore */
 527
 528 static int      dodump = 1;
 529
 530 SYSCTL_INT(_machdep, OID_AUTO, do_dump, CTLFLAG_RW, &dodump, 0,
 531     "Try to perform coredump on kernel panic");
 532
 533 static int
 534 setdumpdev(cdev_t dev)
 535 {
 536         int psize;
 537         long newdumplo;
 538
 539         if (dev == NOCDEV) {
 540                 dumpdev = dev;
 541                 return (0);
 542         }
 543         psize = dev_dpsize(dev);
 544         if (psize == -1)
 545                 return (ENXIO);
 546         /*
 547          * XXX should clean up checking in dumpsys() to be more like this.
 548          */
 549         newdumplo = psize - Maxmem * (PAGE_SIZE / DEV_BSIZE);
 550         if (newdumplo <= LABELSECTOR)
 551                 return (ENOSPC);
 552         dumpdev = dev;
 553         dumplo = newdumplo;
 554         return (0);
 555 }
 556
 557
 558 /* ARGSUSED */
 559 static void dump_conf (void *dummy);
 560 static void
 561 dump_conf(void *dummy)
 562 {
 563         char *path;
 564         cdev_t dev;
 565
 566         path = kmalloc(MNAMELEN, M_TEMP, M_WAITOK);
 567         if (TUNABLE_STR_FETCH("dumpdev", path, MNAMELEN) != 0) {
 568                 dev = kgetdiskbyname(path);
 569                 if (dev != NOCDEV)
 570                         dumpdev = dev;
 571         }
 572         kfree(path, M_TEMP);
 573         if (setdumpdev(dumpdev) != 0)
 574                 dumpdev = NOCDEV;
 575 }
 576
 577 SYSINIT(dump_conf, SI_SUB_DUMP_CONF, SI_ORDER_FIRST, dump_conf, NULL)
 578
 579 static int
 580 sysctl_kern_dumpdev(SYSCTL_HANDLER_ARGS)
 581 {
 582         int error;
 583         udev_t ndumpdev;
 584
 585         ndumpdev = dev2udev(dumpdev);
 586         error = sysctl_handle_opaque(oidp, &ndumpdev, sizeof ndumpdev, req);
 587         if (error == 0 && req->newptr != NULL)
 588                 error = setdumpdev(udev2dev(ndumpdev, 0));
 589         return (error);
 590 }
 591
 592 SYSCTL_PROC(_kern, KERN_DUMPDEV, dumpdev, CTLTYPE_OPAQUE|CTLFLAG_RW,
 593         0, sizeof dumpdev, sysctl_kern_dumpdev, "T,udev_t", "");
 594
 595 /*
 596  * Doadump comes here after turning off memory management and
 597  * getting on the dump stack, either when called above, or by
 598  * the auto-restart code.
 599  */
 600 static void
 601 dumpsys(void)
 602 {
 603         int     error;
 604
 605         savectx(&dumppcb);
 606         dumpthread = curthread;
 607         if (dumping++) {
 608                 kprintf("Dump already in progress, bailing...\n");
 609                 return;
 610         }
 611         if (!dodump)
 612                 return;
 613         if (dumpdev == NOCDEV)
 614                 return;
 615         dumpsize = Maxmem;
 616         kprintf("\ndumping to dev %s, offset %ld\n", devtoname(dumpdev), dumplo);
 617         kprintf("dump ");
 618         error = dev_ddump(dumpdev);
 619         if (error == 0) {
 620                 kprintf("succeeded\n");
 621                 return;
 622         }
 623         kprintf("failed, reason: ");
 624         switch (error) {
 625         case ENOSYS:
 626         case ENODEV:
 627                 kprintf("device doesn't support a dump routine\n");
 628                 break;
 629
 630         case ENXIO:
 631                 kprintf("device bad\n");
 632                 break;
 633
 634         case EFAULT:
 635                 kprintf("device not ready\n");
 636                 break;
 637
 638         case EINVAL:
 639                 kprintf("area improper\n");
 640                 break;
 641
 642         case EIO:
 643                 kprintf("i/o error\n");
 644                 break;
 645
 646         case EINTR:
 647                 kprintf("aborted from console\n");
 648                 break;
 649
 650         default:
 651                 kprintf("unknown, error = %d\n", error);
 652                 break;
 653         }
 654 }
 655
 656 int
 657 dumpstatus(vm_offset_t addr, off_t count)
 658 {
 659         int c;
 660
 661         if (addr % (1024 * 1024) == 0) {
 662 #ifdef HW_WDOG
 663                 if (wdog_tickler)
 664                         (*wdog_tickler)();
 665 #endif
 666                 kprintf("%ld ", (long)(count / (1024 * 1024)));
 667         }
 668
 669         if ((c = cncheckc()) == 0x03)
 670                 return -1;
 671         else if (c != -1)
 672                 kprintf("[CTRL-C to abort] ");
 673
 674         return 0;
 675 }
 676
 677 /*
 678  * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
 679  * and then reboots.  If we are called twice, then we avoid trying to sync
 680  * the disks as this often leads to recursive panics.
 681  */
 682 void
 683 panic(const char *fmt, ...)
 684 {
 685         int bootopt, newpanic;
 686         __va_list ap;
 687         static char buf[256];
 688
 689 #ifdef SMP
 690         /*
 691          * If a panic occurs on multiple cpus before the first is able to
 692          * halt the other cpus, only one cpu is allowed to take the panic.
 693          * Attempt to be verbose about this situation but if the kprintf()
 694          * itself panics don't let us overrun the kernel stack.
 695          *
 696          * Be very nasty about descheduling our thread at the lowest
 697          * level possible in an attempt to freeze the thread without
 698          * inducing further panics.
 699          *
 700          * Bumping gd_trap_nesting_level will also bypass assertions in
 701          * lwkt_switch() and allow us to switch away even if we are a
 702          * FAST interrupt or IPI.
 703          */
 704         if (atomic_poll_acquire_int(&panic_cpu_interlock)) {
 705                 panic_cpu_gd = mycpu;
 706         } else if (panic_cpu_gd != mycpu) {
 707                 crit_enter();
 708                 ++mycpu->gd_trap_nesting_level;
 709                 if (mycpu->gd_trap_nesting_level < 25) {
 710                         kprintf("SECONDARY PANIC ON CPU %d THREAD %p\n",
 711                                 mycpu->gd_cpuid, curthread);
 712                 }
 713                 curthread->td_release = NULL;   /* be a grinch */
 714                 for (;;) {
 715                         lwkt_deschedule_self(curthread);
 716                         lwkt_switch();
 717                 }
 718                 /* NOT REACHED */
 719                 /* --mycpu->gd_trap_nesting_level */
 720                 /* crit_exit() */
 721         }
 722 #endif
 723         bootopt = RB_AUTOBOOT | RB_DUMP;
 724         if (sync_on_panic == 0)
 725                 bootopt |= RB_NOSYNC;
 726         newpanic = 0;
 727         if (panicstr)
 728                 bootopt |= RB_NOSYNC;
 729         else {
 730                 panicstr = fmt;
 731                 newpanic = 1;
 732         }
 733
 734         __va_start(ap, fmt);
 735         kvsnprintf(buf, sizeof(buf), fmt, ap);
 736         if (panicstr == fmt)
 737                 panicstr = buf;
 738         __va_end(ap);
 739         kprintf("panic: %s\n", buf);
 740 #ifdef SMP
 741         /* three separate prints in case of an unmapped page and trap */
 742         kprintf("mp_lock = %08x; ", mp_lock);
 743         kprintf("cpuid = %d; ", mycpu->gd_cpuid);
 744         kprintf("lapic.id = %08x\n", lapic.id);
 745 #endif
 746
 747 #if defined(DDB)
 748         if (newpanic && trace_on_panic)
 749                 db_print_backtrace();
 750         if (debugger_on_panic)
 751                 Debugger ("panic");
 752 #endif
 753         boot(bootopt);
 754 }
 755
 756 /*
 757  * Support for poweroff delay.
 758  */
 759 #ifndef POWEROFF_DELAY
 760 # define POWEROFF_DELAY 5000
 761 #endif
 762 static int poweroff_delay = POWEROFF_DELAY;
 763
 764 SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
 765         &poweroff_delay, 0, "");
 766
 767 static void
 768 poweroff_wait(void *junk, int howto)
 769 {
 770         if(!(howto & RB_POWEROFF) || poweroff_delay <= 0)
 771                 return;
 772         DELAY(poweroff_delay * 1000);
 773 }
 774
 775 /*
 776  * Some system processes (e.g. syncer) need to be stopped at appropriate
 777  * points in their main loops prior to a system shutdown, so that they
 778  * won't interfere with the shutdown process (e.g. by holding a disk buf
 779  * to cause sync to fail).  For each of these system processes, register
 780  * shutdown_kproc() as a handler for one of shutdown events.
 781  */
 782 static int kproc_shutdown_wait = 60;
 783 SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
 784     &kproc_shutdown_wait, 0, "");
 785
 786 void
 787 shutdown_kproc(void *arg, int howto)
 788 {
 789         struct thread *td;
 790         struct proc *p;
 791         int error;
 792
 793         if (panicstr)
 794                 return;
 795
 796         td = (struct thread *)arg;
 797         if ((p = td->td_proc) != NULL) {
 798             kprintf("Waiting (max %d seconds) for system process `%s' to stop...",
 799                 kproc_shutdown_wait, p->p_comm);
 800         } else {
 801             kprintf("Waiting (max %d seconds) for system thread %s to stop...",
 802                 kproc_shutdown_wait, td->td_comm);
 803         }
 804         error = suspend_kproc(td, kproc_shutdown_wait * hz);
 805
 806         if (error == EWOULDBLOCK)
 807                 kprintf("timed out\n");
 808         else
 809                 kprintf("stopped\n");
 810 }