1/* Native-dependent code for NetBSD/i386.
2
3   Copyright 2004 Free Software Foundation, Inc.
4
5   This file is part of GDB.
6
7   This program is free software; you can redistribute it and/or modify
8   it under the terms of the GNU General Public License as published by
9   the Free Software Foundation; either version 2 of the License, or
10   (at your option) any later version.
11
12   This program is distributed in the hope that it will be useful,
13   but WITHOUT ANY WARRANTY; without even the implied warranty of
14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15   GNU General Public License for more details.
16
17   You should have received a copy of the GNU General Public License
18   along with this program; if not, write to the Free Software
19   Foundation, Inc., 59 Temple Place - Suite 330,
20   Boston, MA 02111-1307, USA.  */
21
22#include "defs.h"
23#include "gdbcore.h"
24#include "regcache.h"
25#include "target.h"
26
27#include "i386-tdep.h"
28#include "i386bsd-nat.h"
29
30/* Support for debugging kernel virtual memory images.  */
31
32#include <sys/types.h>
33#include <machine/frame.h>
34#include <machine/pcb.h>
35
36#include "bsd-kvm.h"
37
38static int
39i386nbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
40{
41  struct switchframe sf;
42
43  /* The following is true for NetBSD 1.6.2:
44
45     The pcb contains %esp and %ebp at the point of the context switch
46     in cpu_switch().  At that point we have a stack frame as
47     described by `struct switchframe', which for NetBSD 1.6.2 has the
48     following layout:
49
50     interrupt level
51     %edi
52     %esi
53     %ebx
54     %eip
55
56     we reconstruct the register state as it would look when we just
57     returned from cpu_switch().  */
58
59  /* The stack pointer shouldn't be zero.  */
60  if (pcb->pcb_esp == 0)
61    return 0;
62
63  read_memory (pcb->pcb_esp, (char *) &sf, sizeof sf);
64  pcb->pcb_esp += sizeof (struct switchframe);
65  regcache_raw_supply (regcache, I386_EDI_REGNUM, &sf.sf_edi);
66  regcache_raw_supply (regcache, I386_ESI_REGNUM, &sf.sf_esi);
67  regcache_raw_supply (regcache, I386_EBP_REGNUM, &pcb->pcb_ebp);
68  regcache_raw_supply (regcache, I386_ESP_REGNUM, &pcb->pcb_esp);
69  regcache_raw_supply (regcache, I386_EBX_REGNUM, &sf.sf_ebx);
70  regcache_raw_supply (regcache, I386_EIP_REGNUM, &sf.sf_eip);
71
72  return 1;
73}
74
75
76/* Provide a prototype to silence -Wmissing-prototypes.  */
77void _initialize_i386nbsd_nat (void);
78
79void
80_initialize_i386nbsd_nat (void)
81{
82  /* We've got nothing to add to the common *BSD/i386 target.  */
83  add_target (i386bsd_target ());
84
85  /* Support debugging kernel virtual memory images.  */
86  bsd_kvm_add_target (i386nbsd_supply_pcb);
87}
88