1 /* $NetBSD: x86.c,v 1.4 2018/08/12 16:00:41 christos Exp $ */
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: x86.c,v 1.4 2018/08/12 16:00:41 christos Exp $");
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 #include <x86/db_machdep.h>
47
48 #include "extern.h"
49
50 #ifdef VM_MIN_KERNEL_ADDRESS_DEFAULT
51 vaddr_t vm_min_kernel_address = VM_MIN_KERNEL_ADDRESS_DEFAULT;
52 #endif
53
54 static struct nlist nl[] = {
55 { .n_name = "_dumppcb" },
56 #ifdef VM_MIN_KERNEL_ADDRESS_DEFAULT
57 { .n_name = "vm_min_kernel_address" },
58 #endif
59 { .n_name = NULL },
60 };
61
62 struct pcb pcb;
63
64 void
db_mach_init(kvm_t * kd)65 db_mach_init(kvm_t *kd)
66 {
67
68 if (kvm_nlist(kd, nl) == -1) {
69 errx(EXIT_FAILURE, "kvm_nlist: %s", kvm_geterr(kd));
70 }
71 if ((size_t)kvm_read(kd, nl[0].n_value, &pcb, sizeof(pcb)) !=
72 sizeof(pcb)) {
73 errx(EXIT_FAILURE, "cannot read dumppcb: %s", kvm_geterr(kd));
74 }
75 #ifdef VM_MIN_KERNEL_ADDRESS_DEFAULT
76 if ((size_t)kvm_read(kd, nl[1].n_value, &vm_min_kernel_address,
77 sizeof(vm_min_kernel_address)) != sizeof(vm_min_kernel_address)) {
78 errx(EXIT_FAILURE, "cannot read vm_min_kernel_address: %s",
79 kvm_geterr(kd));
80 }
81 #endif
82 ddb_regs.tf_sp = pcb.pcb_sp;
83 ddb_regs.tf_bp = pcb.pcb_bp;
84 if (ddb_regs.tf_bp != 0 && ddb_regs.tf_sp != 0) {
85 printf("Backtrace from time of crash is available.\n");
86 }
87 }
88