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
51vaddr_t vm_min_kernel_address = VM_MIN_KERNEL_ADDRESS_DEFAULT;
52#endif
53
54static 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
62struct pcb	pcb;
63
64void
65db_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