i386nbsd-nat.c revision 1.3 
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
26#include "i386-tdep.h"
27
28/* Support for debugging kernel virtual memory images.  */
29
30#include <sys/types.h>
31#include <machine/frame.h>
32#include <machine/pcb.h>
33
34#include "bsd-kvm.h"
35
36int
37bsd_kvm_supply_pcb (struct regcache *regcache, struct pcb *pcb)
38{
39  struct switchframe sf;
40
41  /* The following is true for NetBSD 1.6.2:
42
43     The pcb contains %esp and %ebp at the point of the context switch
44     in cpu_switch().  At that point we have a stack frame as
45     described by `struct switchframe', which for NetBSD 1.6.2 has the
46     following layout:
47
48     interrupt level
49     %edi
50     %esi
51     %ebx
52     %eip
53
54     we reconstruct the register state as it would look when we just
55     returned from cpu_switch().  */
56
57  /* The stack pointer shouldn't be zero.  */
58  if (pcb->pcb_esp == 0)
59    return 0;
60
61  read_memory (pcb->pcb_esp, (char *) &sf, sizeof sf);
62  pcb->pcb_esp += sizeof (struct switchframe);
63  regcache_raw_supply (regcache, I386_EDI_REGNUM, &sf.sf_edi);
64  regcache_raw_supply (regcache, I386_ESI_REGNUM, &sf.sf_esi);
65  regcache_raw_supply (regcache, I386_EBP_REGNUM, &pcb->pcb_ebp);
66  regcache_raw_supply (regcache, I386_ESP_REGNUM, &pcb->pcb_esp);
67  regcache_raw_supply (regcache, I386_EBX_REGNUM, &sf.sf_ebx);
68  regcache_raw_supply (regcache, I386_EIP_REGNUM, &sf.sf_eip);
69
70  return 1;
71}
72