usr.sbin/crash/arch/i386.c

   1 /*      $NetBSD$        */
   2
   3 /*-
   4  * Copyright (c) 2009 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Andrew Doran.
   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  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #ifndef lint
  34 __RCSID("$NetBSD$");
  35 #endif /* not lint */
  36
  37 #include <ddb/ddb.h>
  38
  39 #include <kvm.h>
  40 #include <nlist.h>
  41 #include <err.h>
  42 #include <stdlib.h>
  43
  44 #include <machine/frame.h>
  45 #include <machine/pcb.h>
  46
  47 #include "extern.h"
  48
  49 static struct nlist nl[] = {
  50         { .n_name = "_dumppcb" },
  51         { .n_name = NULL },
  52 };
  53
  54 struct pcb      pcb;
  55
  56 void
  57 db_mach_init(kvm_t *kd)
  58 {
  59
  60         if (kvm_nlist(kd, nl) == -1) {
  61                 errx(EXIT_FAILURE, "kvm_nlist: %s", kvm_geterr(kd));
  62         }
  63         if ((size_t)kvm_read(kd, nl[0].n_value, &pcb, sizeof(pcb)) !=
  64             sizeof(pcb)) {
  65                 errx(EXIT_FAILURE, "cannot read dumppcb: %s", kvm_geterr(kd));
  66         }
  67         ddb_regs.tf_esp = pcb.pcb_esp;
  68         ddb_regs.tf_ebp = pcb.pcb_ebp;
  69         if (ddb_regs.tf_ebp != 0 && ddb_regs.tf_esp != 0) {
  70                 printf("Backtrace from time of crash is available.\n");
  71         }
  72 }