xref: /src/usr.sbin/crash/arch/x86.c

/*	$NetBSD: x86.c,v 1.4 2018/08/12 16:00:41 christos Exp $	*/

/*-
 * Copyright (c) 2009 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Andrew Doran.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: x86.c,v 1.4 2018/08/12 16:00:41 christos Exp $");
#endif /* not lint */

#include <ddb/ddb.h>

#include <kvm.h>
#include <nlist.h>
#include <err.h>
#include <stdlib.h>

#include <machine/frame.h>
#include <machine/pcb.h>
#include <x86/db_machdep.h>

#include "extern.h"

#ifdef VM_MIN_KERNEL_ADDRESS_DEFAULT
vaddr_t vm_min_kernel_address = VM_MIN_KERNEL_ADDRESS_DEFAULT;
#endif

static struct nlist nl[] = {
	{ .n_name = "_dumppcb" },
#ifdef VM_MIN_KERNEL_ADDRESS_DEFAULT
	{ .n_name = "vm_min_kernel_address" },
#endif
	{ .n_name = NULL },
};

struct pcb	pcb;

void
db_mach_init(kvm_t *kd)
{

	if (kvm_nlist(kd, nl) == -1) {
		errx(EXIT_FAILURE, "kvm_nlist: %s", kvm_geterr(kd));
	}
	if ((size_t)kvm_read(kd, nl[0].n_value, &pcb, sizeof(pcb)) !=
	    sizeof(pcb)) {
		errx(EXIT_FAILURE, "cannot read dumppcb: %s", kvm_geterr(kd));
	}
#ifdef VM_MIN_KERNEL_ADDRESS_DEFAULT
	if ((size_t)kvm_read(kd, nl[1].n_value, &vm_min_kernel_address,
	    sizeof(vm_min_kernel_address)) != sizeof(vm_min_kernel_address)) {
		errx(EXIT_FAILURE, "cannot read vm_min_kernel_address: %s",
		    kvm_geterr(kd));
	}
#endif
        ddb_regs.tf_sp = pcb.pcb_sp;
        ddb_regs.tf_bp = pcb.pcb_bp;
        if (ddb_regs.tf_bp != 0 && ddb_regs.tf_sp != 0) {
        	printf("Backtrace from time of crash is available.\n");
	}
}