aboutsummaryrefslogtreecommitdiff
path: root/gdb/i386bsd-nat.c
blob: fcd772fb9397ce3573c8baa919fca8ceec4eaede (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
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
/* Native-dependent code for modern i386 BSD's.

   Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010,
   2011 Free Software Foundation, 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 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 "inferior.h"
#include "regcache.h"

#include "gdb_assert.h"
#include <signal.h>
#include <stddef.h>
#include <sys/types.h>
#include <sys/ptrace.h>
#include <machine/reg.h>
#include <machine/frame.h>

#include "i386-tdep.h"
#include "i387-tdep.h"
#include "i386bsd-nat.h"
#include "inf-ptrace.h"


/* In older BSD versions we cannot get at some of the segment
   registers.  FreeBSD for example didn't support the %fs and %gs
   registers until the 3.0 release.  We have autoconf checks for their
   presence, and deal gracefully with their absence.  */

/* Offset in `struct reg' where MEMBER is stored.  */
#define REG_OFFSET(member) offsetof (struct reg, member)

/* At i386bsd_reg_offset[REGNUM] you'll find the offset in `struct
   reg' where the GDB register REGNUM is stored.  Unsupported
   registers are marked with `-1'.  */
static int i386bsd_r_reg_offset[] =
{
  REG_OFFSET (r_eax),
  REG_OFFSET (r_ecx),
  REG_OFFSET (r_edx),
  REG_OFFSET (r_ebx),
  REG_OFFSET (r_esp),
  REG_OFFSET (r_ebp),
  REG_OFFSET (r_esi),
  REG_OFFSET (r_edi),
  REG_OFFSET (r_eip),
  REG_OFFSET (r_eflags),
  REG_OFFSET (r_cs),
  REG_OFFSET (r_ss),
  REG_OFFSET (r_ds),
  REG_OFFSET (r_es),
#ifdef HAVE_STRUCT_REG_R_FS
  REG_OFFSET (r_fs),
#else
  -1,
#endif
#ifdef HAVE_STRUCT_REG_R_GS
  REG_OFFSET (r_gs)
#else
  -1
#endif
};

/* Macro to determine if a register is fetched with PT_GETREGS.  */
#define GETREGS_SUPPLIES(regnum) \
  ((0 <= (regnum) && (regnum) <= 15))

#ifdef HAVE_PT_GETXMMREGS
/* Set to 1 if the kernel supports PT_GETXMMREGS.  Initialized to -1
   so that we try PT_GETXMMREGS the first time around.  */
static int have_ptrace_xmmregs = -1;
#endif


/* Supply the general-purpose registers in GREGS, to REGCACHE.  */

static void
i386bsd_supply_gregset (struct regcache *regcache, const void *gregs)
{
  const char *regs = gregs;
  int regnum;

  for (regnum = 0; regnum < ARRAY_SIZE (i386bsd_r_reg_offset); regnum++)
    {
      int offset = i386bsd_r_reg_offset[regnum];

      if (offset != -1)
	regcache_raw_supply (regcache, regnum, regs + offset);
    }
}

/* Collect register REGNUM from REGCACHE and store its contents in
   GREGS.  If REGNUM is -1, collect and store all appropriate
   registers.  */

static void
i386bsd_collect_gregset (const struct regcache *regcache,
			 void *gregs, int regnum)
{
  char *regs = gregs;
  int i;

  for (i = 0; i < ARRAY_SIZE (i386bsd_r_reg_offset); i++)
    {
      if (regnum == -1 || regnum == i)
	{
	  int offset = i386bsd_r_reg_offset[i];

	  if (offset != -1)
	    regcache_raw_collect (regcache, i, regs + offset);
	}
    }
}

/* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
   for all registers (including the floating point registers).  */

static void
i386bsd_fetch_inferior_registers (struct target_ops *ops,
				  struct regcache *regcache, int regnum)
{
  if (regnum == -1 || GETREGS_SUPPLIES (regnum))
    {
      struct reg regs;

      if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
		  (PTRACE_TYPE_ARG3) &regs, 0) == -1)
	perror_with_name (_("Couldn't get registers"));

      i386bsd_supply_gregset (regcache, &regs);
      if (regnum != -1)
	return;
    }

  if (regnum == -1 || regnum >= I386_ST0_REGNUM)
    {
      struct fpreg fpregs;
#ifdef HAVE_PT_GETXMMREGS
      char xmmregs[512];

      if (have_ptrace_xmmregs != 0
	  && ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid),
		    (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
	{
	  have_ptrace_xmmregs = 1;
	  i387_supply_fxsave (regcache, -1, xmmregs);
	}
      else
	{
          if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
		      (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
	    perror_with_name (_("Couldn't get floating point status"));

	  i387_supply_fsave (regcache, -1, &fpregs);
	}
#else
      if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
	perror_with_name (_("Couldn't get floating point status"));

      i387_supply_fsave (regcache, -1, &fpregs);
#endif
    }
}

/* Store register REGNUM back into the inferior.  If REGNUM is -1, do
   this for all registers (including the floating point registers).  */

static void
i386bsd_store_inferior_registers (struct target_ops *ops,
				  struct regcache *regcache, int regnum)
{
  if (regnum == -1 || GETREGS_SUPPLIES (regnum))
    {
      struct reg regs;

      if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
                  (PTRACE_TYPE_ARG3) &regs, 0) == -1)
        perror_with_name (_("Couldn't get registers"));

      i386bsd_collect_gregset (regcache, &regs, regnum);

      if (ptrace (PT_SETREGS, PIDGET (inferior_ptid),
	          (PTRACE_TYPE_ARG3) &regs, 0) == -1)
        perror_with_name (_("Couldn't write registers"));

      if (regnum != -1)
	return;
    }

  if (regnum == -1 || regnum >= I386_ST0_REGNUM)
    {
      struct fpreg fpregs;
#ifdef HAVE_PT_GETXMMREGS
      char xmmregs[512];

      if (have_ptrace_xmmregs != 0
	  && ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid),
		    (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
	{
	  have_ptrace_xmmregs = 1;

	  i387_collect_fxsave (regcache, regnum, xmmregs);

	  if (ptrace (PT_SETXMMREGS, PIDGET (inferior_ptid),
		      (PTRACE_TYPE_ARG3) xmmregs, 0) == -1)
            perror_with_name (_("Couldn't write XMM registers"));
	}
      else
	{
	  have_ptrace_xmmregs = 0;
#endif
          if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
		      (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
	    perror_with_name (_("Couldn't get floating point status"));

          i387_collect_fsave (regcache, regnum, &fpregs);

          if (ptrace (PT_SETFPREGS, PIDGET (inferior_ptid),
		      (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
	    perror_with_name (_("Couldn't write floating point status"));
#ifdef HAVE_PT_GETXMMREGS
        }
#endif
    }
}

/* Create a prototype *BSD/i386 target.  The client can override it
   with local methods.  */

struct target_ops *
i386bsd_target (void)
{
  struct target_ops *t;

  t = inf_ptrace_target ();
  t->to_fetch_registers = i386bsd_fetch_inferior_registers;
  t->to_store_registers = i386bsd_store_inferior_registers;
  return t;
}


/* Support for debug registers.  */

#ifdef HAVE_PT_GETDBREGS

/* Not all versions of FreeBSD/i386 that support the debug registers
   have this macro.  */
#ifndef DBREG_DRX
#define DBREG_DRX(d, x) ((&d->dr0)[x])
#endif

static void
i386bsd_dr_set (int regnum, unsigned int value)
{
  struct dbreg dbregs;

  if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
              (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
    perror_with_name (_("Couldn't get debug registers"));

  /* For some mysterious reason, some of the reserved bits in the
     debug control register get set.  Mask these off, otherwise the
     ptrace call below will fail.  */
  DBREG_DRX ((&dbregs), 7) &= ~(0x0000fc00);

  DBREG_DRX ((&dbregs), regnum) = value;

  if (ptrace (PT_SETDBREGS, PIDGET (inferior_ptid),
              (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
    perror_with_name (_("Couldn't write debug registers"));
}

void
i386bsd_dr_set_control (unsigned long control)
{
  i386bsd_dr_set (7, control);
}

void
i386bsd_dr_set_addr (int regnum, CORE_ADDR addr)
{
  gdb_assert (regnum >= 0 && regnum <= 4);

  i386bsd_dr_set (regnum, addr);
}

void
i386bsd_dr_reset_addr (int regnum)
{
  gdb_assert (regnum >= 0 && regnum <= 4);

  i386bsd_dr_set (regnum, 0);
}

unsigned long
i386bsd_dr_get_status (void)
{
  struct dbreg dbregs;

  if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
	      (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
    perror_with_name (_("Couldn't read debug registers"));

  return DBREG_DRX ((&dbregs), 6);
}

#endif /* PT_GETDBREGS */


void
_initialize_i386bsd_nat (void)
{
  int offset;

  /* To support the recognition of signal handlers, i386bsd-tdep.c
     hardcodes some constants.  Inclusion of this file means that we
     are compiling a native debugger, which means that we can use the
     system header files and sysctl(3) to get at the relevant
     information.  */

#if defined (__FreeBSD_version) && __FreeBSD_version >= 400011
#define SC_REG_OFFSET i386fbsd4_sc_reg_offset
#elif defined (__FreeBSD_version) && __FreeBSD_version >= 300005
#define SC_REG_OFFSET i386fbsd_sc_reg_offset
#elif defined (NetBSD) || defined (__NetBSD_Version__)
#define SC_REG_OFFSET i386nbsd_sc_reg_offset
#elif defined (OpenBSD)
#define SC_REG_OFFSET i386obsd_sc_reg_offset
#endif

#ifdef SC_REG_OFFSET

  /* We only check the program counter, stack pointer and frame
     pointer since these members of `struct sigcontext' are essential
     for providing backtraces.  More checks could be added, but would
     involve adding configure checks for the appropriate structure
     members, since older BSD's don't provide all of them.  */

#define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM]
#define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM]
#define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM]

  /* Override the default value for the offset of the program counter
     in the sigcontext structure.  */
  offset = offsetof (struct sigcontext, sc_pc);

  if (SC_PC_OFFSET != offset)
    {
      warning (_("\
offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\
Please report this to <bug-gdb@gnu.org>."), 
	       offset, SC_PC_OFFSET);
    }

  SC_PC_OFFSET = offset;

  /* Likewise for the stack pointer.  */
  offset = offsetof (struct sigcontext, sc_sp);

  if (SC_SP_OFFSET != offset)
    {
      warning (_("\
offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\
Please report this to <bug-gdb@gnu.org>."),
	       offset, SC_SP_OFFSET);
    }

  SC_SP_OFFSET = offset;

  /* And the frame pointer.  */
  offset = offsetof (struct sigcontext, sc_fp);

  if (SC_FP_OFFSET != offset)
    {
      warning (_("\
offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\
Please report this to <bug-gdb@gnu.org>."),
	       offset, SC_FP_OFFSET);
    }

  SC_FP_OFFSET = offset;

#endif /* SC_REG_OFFSET */
}