1/* Native-dependent code for NetBSD/i386.
2
3   Copyright (C) 2004, 2005, 2007 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 3 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, see <http://www.gnu.org/licenses/>.  */
19
20#include "defs.h"
21#include "gdbcore.h"
22#include "regcache.h"
23#include "target.h"
24
25#include "i386-tdep.h"
26#include "i386bsd-nat.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 "nbsd-nat.h"
35#include "bsd-kvm.h"
36
37static int
38i386nbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
39{
40  struct switchframe sf;
41
42  /* The following is true for NetBSD 1.6.2:
43
44     The pcb contains %esp and %ebp at the point of the context switch
45     in cpu_switch().  At that point we have a stack frame as
46     described by `struct switchframe', which for NetBSD 1.6.2 has the
47     following layout:
48
49     interrupt level
50     %edi
51     %esi
52     %ebx
53     %eip
54
55     we reconstruct the register state as it would look when we just
56     returned from cpu_switch().  */
57
58  /* The stack pointer shouldn't be zero.  */
59  if (pcb->pcb_esp == 0)
60    return 0;
61
62  read_memory (pcb->pcb_esp, (gdb_byte *)&sf, sizeof sf);
63  pcb->pcb_esp += sizeof (struct switchframe);
64  regcache_raw_supply (regcache, I386_EDI_REGNUM, &sf.sf_edi);
65  regcache_raw_supply (regcache, I386_ESI_REGNUM, &sf.sf_esi);
66  regcache_raw_supply (regcache, I386_EBP_REGNUM, &pcb->pcb_ebp);
67  regcache_raw_supply (regcache, I386_ESP_REGNUM, &pcb->pcb_esp);
68  regcache_raw_supply (regcache, I386_EBX_REGNUM, &sf.sf_ebx);
69  regcache_raw_supply (regcache, I386_EIP_REGNUM, &sf.sf_eip);
70
71  return 1;
72}
73
74
75/* Provide a prototype to silence -Wmissing-prototypes.  */
76void _initialize_i386nbsd_nat (void);
77
78void
79_initialize_i386nbsd_nat (void)
80{
81  struct target_ops *t;
82
83  /* Add some extra features to the common *BSD/i386 target.  */
84  t = i386bsd_target ();
85  t->to_pid_to_exec_file = nbsd_pid_to_exec_file;
86  add_target (t);
87
88  /* Support debugging kernel virtual memory images.  */
89  bsd_kvm_add_target (i386nbsd_supply_pcb);
90}
91