aboutsummaryrefslogtreecommitdiff
path: root/gdb/i386-nto-tdep.c
blob: 4d443e667ff2d7ebea177ace4bd654365fc5da12 (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
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
/* Target-dependent code for QNX Neutrino x86.

   Copyright (C) 2003-2021 Free Software Foundation, Inc.

   Contributed by QNX Software Systems Ltd.

   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 3 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, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "frame.h"
#include "osabi.h"
#include "regcache.h"
#include "target.h"

#include "i386-tdep.h"
#include "i387-tdep.h"
#include "nto-tdep.h"
#include "solib.h"
#include "solib-svr4.h"

#ifndef X86_CPU_FXSR
#define X86_CPU_FXSR (1L << 12)
#endif

/* Why 13?  Look in our /usr/include/x86/context.h header at the
   x86_cpu_registers structure and you'll see an 'exx' junk register
   that is just filler.  Don't ask me, ask the kernel guys.  */
#define NUM_GPREGS 13

/* Mapping between the general-purpose registers in `struct xxx'
   format and GDB's register cache layout.  */

/* From <x86/context.h>.  */
static int i386nto_gregset_reg_offset[] =
{
  7 * 4,			/* %eax */
  6 * 4,			/* %ecx */
  5 * 4,			/* %edx */
  4 * 4,			/* %ebx */
  11 * 4,			/* %esp */
  2 * 4,			/* %epb */
  1 * 4,			/* %esi */
  0 * 4,			/* %edi */
  8 * 4,			/* %eip */
  10 * 4,			/* %eflags */
  9 * 4,			/* %cs */
  12 * 4,			/* %ss */
  -1				/* filler */
};

/* Given a GDB register number REGNUM, return the offset into
   Neutrino's register structure or -1 if the register is unknown.  */

static int
nto_reg_offset (int regnum)
{
  if (regnum >= 0 && regnum < ARRAY_SIZE (i386nto_gregset_reg_offset))
    return i386nto_gregset_reg_offset[regnum];

  return -1;
}

static void
i386nto_supply_gregset (struct regcache *regcache, char *gpregs)
{
  struct gdbarch *gdbarch = regcache->arch ();
  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);

  gdb_assert (tdep->gregset_reg_offset == i386nto_gregset_reg_offset);
  i386_gregset.supply_regset (&i386_gregset, regcache, -1,
			      gpregs, NUM_GPREGS * 4);
}

static void
i386nto_supply_fpregset (struct regcache *regcache, char *fpregs)
{
  if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
    i387_supply_fxsave (regcache, -1, fpregs);
  else
    i387_supply_fsave (regcache, -1, fpregs);
}

static void
i386nto_supply_regset (struct regcache *regcache, int regset, char *data)
{
  switch (regset)
    {
    case NTO_REG_GENERAL:
      i386nto_supply_gregset (regcache, data);
      break;
    case NTO_REG_FLOAT:
      i386nto_supply_fpregset (regcache, data);
      break;
    }
}

static int
i386nto_regset_id (int regno)
{
  if (regno == -1)
    return NTO_REG_END;
  else if (regno < I386_NUM_GREGS)
    return NTO_REG_GENERAL;
  else if (regno < I386_NUM_GREGS + I387_NUM_REGS)
    return NTO_REG_FLOAT;
  else if (regno < I386_SSE_NUM_REGS)
    return NTO_REG_FLOAT; /* We store xmm registers in fxsave_area.  */

  return -1;			/* Error.  */
}

static int
i386nto_register_area (struct gdbarch *gdbarch,
		       int regno, int regset, unsigned *off)
{
  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);

  *off = 0;
  if (regset == NTO_REG_GENERAL)
    {
      if (regno == -1)
	return NUM_GPREGS * 4;

      *off = nto_reg_offset (regno);
      if (*off == -1)
	return 0;
      return 4;
    }
  else if (regset == NTO_REG_FLOAT)
    {
      unsigned off_adjust, regsize, regset_size, regno_base;
      /* The following are flags indicating number in our fxsave_area.  */
      int first_four = (regno >= I387_FCTRL_REGNUM (tdep)
			&& regno <= I387_FISEG_REGNUM (tdep));
      int second_four = (regno > I387_FISEG_REGNUM (tdep)
			 && regno <= I387_FOP_REGNUM (tdep));
      int st_reg = (regno >= I387_ST0_REGNUM (tdep)
		    && regno < I387_ST0_REGNUM (tdep) + 8);
      int xmm_reg = (regno >= I387_XMM0_REGNUM (tdep)
		     && regno < I387_MXCSR_REGNUM (tdep));

      if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
	{
	  off_adjust = 32;
	  regsize = 16;
	  regset_size = 512;
	  /* fxsave_area structure.  */
	  if (first_four)
	    {
	      /* fpu_control_word, fpu_status_word, fpu_tag_word, fpu_operand
		 registers.  */
	      regsize = 2; /* Two bytes each.  */
	      off_adjust = 0;
	      regno_base = I387_FCTRL_REGNUM (tdep);
	    }
	  else if (second_four)
	    {
	      /* fpu_ip, fpu_cs, fpu_op, fpu_ds registers.  */
	      regsize = 4;
	      off_adjust = 8;
	      regno_base = I387_FISEG_REGNUM (tdep) + 1;
	    }
	  else if (st_reg)
	    {
	      /* ST registers.  */
	      regsize = 16;
	      off_adjust = 32;
	      regno_base = I387_ST0_REGNUM (tdep);
	    }
	  else if (xmm_reg)
	    {
	      /* XMM registers.  */
	      regsize = 16;
	      off_adjust = 160;
	      regno_base = I387_XMM0_REGNUM (tdep);
	    }
	  else if (regno == I387_MXCSR_REGNUM (tdep))
	    {
	      regsize = 4;
	      off_adjust = 24;
	      regno_base = I387_MXCSR_REGNUM (tdep);
	    }
	  else
	    {
	      /* Whole regset.  */
	      gdb_assert (regno == -1);
	      off_adjust = 0;
	      regno_base = 0;
	      regsize = regset_size;
	    }
	}
      else
	{
	  regset_size = 108;
	  /* fsave_area structure.  */
	  if (first_four || second_four)
	    {
	      /* fpu_control_word, ... , fpu_ds registers.  */
	      regsize = 4;
	      off_adjust = 0;
	      regno_base = I387_FCTRL_REGNUM (tdep);
	    }
	  else if (st_reg)
	    {
	      /* One of ST registers.  */
	      regsize = 10;
	      off_adjust = 7 * 4;
	      regno_base = I387_ST0_REGNUM (tdep);
	    }
	  else
	    {
	      /* Whole regset.  */
	      gdb_assert (regno == -1);
	      off_adjust = 0;
	      regno_base = 0;
	      regsize = regset_size;
	    }
	}

      if (regno != -1)
	*off = off_adjust + (regno - regno_base) * regsize;
      else
	*off = 0;
      return regsize;
    }
  return -1;
}

static int
i386nto_regset_fill (const struct regcache *regcache, int regset, char *data)
{
  if (regset == NTO_REG_GENERAL)
    {
      int regno;

      for (regno = 0; regno < NUM_GPREGS; regno++)
	{
	  int offset = nto_reg_offset (regno);
	  if (offset != -1)
	    regcache->raw_collect (regno, data + offset);
	}
    }
  else if (regset == NTO_REG_FLOAT)
    {
      if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
	i387_collect_fxsave (regcache, -1, data);
      else
	i387_collect_fsave (regcache, -1, data);
    }
  else
    return -1;

  return 0;
}

/* Return whether THIS_FRAME corresponds to a QNX Neutrino sigtramp
   routine.  */

static int
i386nto_sigtramp_p (struct frame_info *this_frame)
{
  CORE_ADDR pc = get_frame_pc (this_frame);
  const char *name;

  find_pc_partial_function (pc, &name, NULL, NULL);
  return name && strcmp ("__signalstub", name) == 0;
}

/* Assuming THIS_FRAME is a QNX Neutrino sigtramp routine, return the
   address of the associated sigcontext structure.  */

static CORE_ADDR
i386nto_sigcontext_addr (struct frame_info *this_frame)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  gdb_byte buf[4];
  CORE_ADDR ptrctx;

  /* We store __ucontext_t addr in EDI register.  */
  get_frame_register (this_frame, I386_EDI_REGNUM, buf);
  ptrctx = extract_unsigned_integer (buf, 4, byte_order);
  ptrctx += 24 /* Context pointer is at this offset.  */;

  return ptrctx;
}

static void
init_i386nto_ops (void)
{
  nto_regset_id = i386nto_regset_id;
  nto_supply_gregset = i386nto_supply_gregset;
  nto_supply_fpregset = i386nto_supply_fpregset;
  nto_supply_altregset = nto_dummy_supply_regset;
  nto_supply_regset = i386nto_supply_regset;
  nto_register_area = i386nto_register_area;
  nto_regset_fill = i386nto_regset_fill;
  nto_fetch_link_map_offsets =
    svr4_ilp32_fetch_link_map_offsets;
}

static void
i386nto_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
  static struct target_so_ops nto_svr4_so_ops;

  /* Deal with our strange signals.  */
  nto_initialize_signals ();

  /* NTO uses ELF.  */
  i386_elf_init_abi (info, gdbarch);

  /* Neutrino rewinds to look more normal.  Need to override the i386
     default which is [unfortunately] to decrement the PC.  */
  set_gdbarch_decr_pc_after_break (gdbarch, 0);

  tdep->gregset_reg_offset = i386nto_gregset_reg_offset;
  tdep->gregset_num_regs = ARRAY_SIZE (i386nto_gregset_reg_offset);
  tdep->sizeof_gregset = NUM_GPREGS * 4;

  tdep->sigtramp_p = i386nto_sigtramp_p;
  tdep->sigcontext_addr = i386nto_sigcontext_addr;
  tdep->sc_reg_offset = i386nto_gregset_reg_offset;
  tdep->sc_num_regs = ARRAY_SIZE (i386nto_gregset_reg_offset);

  /* Setjmp()'s return PC saved in EDX (5).  */
  tdep->jb_pc_offset = 20;	/* 5x32 bit ints in.  */

  set_solib_svr4_fetch_link_map_offsets
    (gdbarch, svr4_ilp32_fetch_link_map_offsets);

  /* Initialize this lazily, to avoid an initialization order
     dependency on solib-svr4.c's _initialize routine.  */
  if (nto_svr4_so_ops.in_dynsym_resolve_code == NULL)
    {
      nto_svr4_so_ops = svr4_so_ops;

      /* Our loader handles solib relocations differently than svr4.  */
      nto_svr4_so_ops.relocate_section_addresses
	= nto_relocate_section_addresses;

      /* Supply a nice function to find our solibs.  */
      nto_svr4_so_ops.find_and_open_solib
	= nto_find_and_open_solib;

      /* Our linker code is in libc.  */
      nto_svr4_so_ops.in_dynsym_resolve_code
	= nto_in_dynsym_resolve_code;
    }
  set_solib_ops (gdbarch, &nto_svr4_so_ops);

  set_gdbarch_wchar_bit (gdbarch, 32);
  set_gdbarch_wchar_signed (gdbarch, 0);
}

void _initialize_i386nto_tdep ();
void
_initialize_i386nto_tdep ()
{
  init_i386nto_ops ();
  gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_QNXNTO,
			  i386nto_init_abi);
  gdbarch_register_osabi_sniffer (bfd_arch_i386, bfd_target_elf_flavour,
				  nto_elf_osabi_sniffer);
}