aboutsummaryrefslogtreecommitdiff
path: root/gdb/alphanbsd-tdep.c
blob: bc7b1a410dbf0b85b9913ca9d36618f56e7817c0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
/* Target-dependent code for NetBSD/Alpha.
   Copyright 2002 Free Software Foundation, Inc.
   Contributed by Wasabi Systems, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include "defs.h"
#include "gdbcore.h"
#include "frame.h"
#include "regcache.h"
#include "value.h"

#include "solib-svr4.h"

#include "alpha-tdep.h"
#include "alphabsd-tdep.h"
#include "nbsd-tdep.h"

static void
fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, int which,
                      CORE_ADDR ignore)
{
  char *regs, *fpregs;
  int regno;

  /* Table to map a gdb register number to a trapframe register index.  */
  static const int regmap[] =
  {
     0,   1,   2,   3,
     4,   5,   6,   7,
     8,   9,  10,  11,
    12,  13,  14,  15, 
    30,  31,  32,  16, 
    17,  18,  19,  20,
    21,  22,  23,  24,
    25,  29,  26
  };
#define SIZEOF_TRAPFRAME (33 * 8)

  /* We get everything from one section.  */
  if (which != 0)
    return;

  regs = core_reg_sect;
  fpregs = core_reg_sect + SIZEOF_TRAPFRAME;

  if (core_reg_size < (SIZEOF_TRAPFRAME + SIZEOF_STRUCT_FPREG))
    {
      warning ("Wrong size register set in core file.");
      return;
    }

  /* Integer registers.  */
  for (regno = 0; regno < ALPHA_ZERO_REGNUM; regno++)
    supply_register (regno, regs + (regmap[regno] * 8));
  supply_register (ALPHA_ZERO_REGNUM, NULL);
  supply_register (FP_REGNUM, NULL);
  supply_register (PC_REGNUM, regs + (28 * 8));

  /* Floating point registers.  */
  alphabsd_supply_fpreg (fpregs, -1);
}

static void
fetch_elfcore_registers (char *core_reg_sect, unsigned core_reg_size, int which,
                         CORE_ADDR ignore)
{
  switch (which)
    {
    case 0:  /* Integer registers.  */
      if (core_reg_size != SIZEOF_STRUCT_REG)
	warning ("Wrong size register set in core file.");
      else
	alphabsd_supply_reg (core_reg_sect, -1);
      break;

    case 2:  /* Floating point registers.  */
      if (core_reg_size != SIZEOF_STRUCT_FPREG)
	warning ("Wrong size FP register set in core file.");
      else
	alphabsd_supply_fpreg (core_reg_sect, -1);
      break;

    default:
      /* Don't know what kind of register request this is; just ignore it.  */
      break;
    }
}

static struct core_fns alphanbsd_core_fns =
{
  bfd_target_unknown_flavour,		/* core_flavour */
  default_check_format,			/* check_format */
  default_core_sniffer,			/* core_sniffer */
  fetch_core_registers,			/* core_read_registers */
  NULL					/* next */
};

static struct core_fns alphanbsd_elfcore_fns =
{
  bfd_target_elf_flavour,		/* core_flavour */
  default_check_format,			/* check_format */
  default_core_sniffer,			/* core_sniffer */
  fetch_elfcore_registers,		/* core_read_registers */
  NULL					/* next */
};

/* Under NetBSD/alpha, signal handler invocations can be identified by the
   designated code sequence that is used to return from a signal handler.
   In particular, the return address of a signal handler points to the
   following code sequence:

	ldq	a0, 0(sp)
	lda	sp, 16(sp)
	lda	v0, 295(zero)	# __sigreturn14
	call_pal callsys

   Each instruction has a unique encoding, so we simply attempt to match
   the instruction the PC is pointing to with any of the above instructions.
   If there is a hit, we know the offset to the start of the designated
   sequence and can then check whether we really are executing in the
   signal trampoline.  If not, -1 is returned, otherwise the offset from the
   start of the return sequence is returned.  */
static const unsigned char sigtramp_retcode[] =
{
  0x00, 0x00, 0x1e, 0xa6,	/* ldq a0, 0(sp) */
  0x10, 0x00, 0xde, 0x23,	/* lda sp, 16(sp) */
  0x27, 0x01, 0x1f, 0x20,	/* lda v0, 295(zero) */
  0x83, 0x00, 0x00, 0x00,	/* call_pal callsys */
};
#define RETCODE_NWORDS		4
#define RETCODE_SIZE		(RETCODE_NWORDS * 4)

LONGEST
alphanbsd_sigtramp_offset (CORE_ADDR pc)
{
  unsigned char ret[RETCODE_SIZE], w[4];
  LONGEST off;
  int i;

  if (read_memory_nobpt (pc, (char *) w, 4) != 0)
    return -1;

  for (i = 0; i < RETCODE_NWORDS; i++)
    {
      if (memcmp (w, sigtramp_retcode + (i * 4), 4) == 0)
	break;
    }
  if (i == RETCODE_NWORDS)
    return (-1);

  off = i * 4;
  pc -= off;

  if (read_memory_nobpt (pc, (char *) ret, sizeof (ret)) != 0)
    return -1;

  if (memcmp (ret, sigtramp_retcode, RETCODE_SIZE) == 0)
    return off;

  return -1;
}

static int
alphanbsd_pc_in_sigtramp (CORE_ADDR pc, char *func_name)
{
  return (nbsd_pc_in_sigtramp (pc, func_name)
	  || alphanbsd_sigtramp_offset (pc) >= 0);
}

static CORE_ADDR
alphanbsd_sigcontext_addr (struct frame_info *frame)
{
  /* FIXME: This is not correct for all versions of NetBSD/alpha.
     We will probably need to disassemble the trampoline to figure
     out which trampoline frame type we have.  */
  return frame->frame;
}

static CORE_ADDR
alphanbsd_skip_sigtramp_frame (struct frame_info *frame, CORE_ADDR pc)
{
  char *name;

  /* FIXME: This is not correct for all versions of NetBSD/alpha.
     We will probably need to disassemble the trampoline to figure
     out which trampoline frame type we have.  */
  find_pc_partial_function (pc, &name, (CORE_ADDR *) NULL, (CORE_ADDR *) NULL);
  if (PC_IN_SIGTRAMP (pc, name))
    return frame->frame;
  return 0;
}

static void
alphanbsd_init_abi (struct gdbarch_info info,
                    struct gdbarch *gdbarch)
{
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  set_gdbarch_pc_in_sigtramp (gdbarch, alphanbsd_pc_in_sigtramp);

  /* NetBSD/alpha does not provide single step support via ptrace(2); we
     must use software single-stepping.  */
  set_gdbarch_software_single_step (gdbarch, alpha_software_single_step);

  set_solib_svr4_fetch_link_map_offsets (gdbarch,
                                 nbsd_lp64_solib_svr4_fetch_link_map_offsets);

  tdep->skip_sigtramp_frame = alphanbsd_skip_sigtramp_frame;
  tdep->dynamic_sigtramp_offset = alphanbsd_sigtramp_offset;
  tdep->sigcontext_addr = alphanbsd_sigcontext_addr;

  tdep->jb_pc = 2;
  tdep->jb_elt_size = 8;
}

void
_initialize_alphanbsd_tdep (void)
{
  gdbarch_register_osabi (bfd_arch_alpha, GDB_OSABI_NETBSD_ELF,
                          alphanbsd_init_abi);

  add_core_fns (&alphanbsd_core_fns);
  add_core_fns (&alphanbsd_elfcore_fns);
}