1 /* Native-dependent code for modern i386 BSD's.
2
3 Copyright 2000, 2001, 2002, 2003, 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 "inferior.h"
24 #include "regcache.h"
25
26 #include "gdb_assert.h"
27 #include <signal.h>
28 #include <stddef.h>
29 #include <sys/types.h>
30 #include <sys/ptrace.h>
31 #include <machine/reg.h>
32 #include <machine/frame.h>
33
34 #include "i386-tdep.h"
35 #include "i387-tdep.h"
36 #include "i386bsd-nat.h"
37 #include "inf-ptrace.h"
38
39
40 /* In older BSD versions we cannot get at some of the segment
41 registers. FreeBSD for example didn't support the %fs and %gs
42 registers until the 3.0 release. We have autoconf checks for their
43 presence, and deal gracefully with their absence. */
44
45 /* Offset in `struct reg' where MEMBER is stored. */
46 #define REG_OFFSET(member) offsetof (struct reg, member)
47
48 /* At i386bsd_reg_offset[REGNUM] you'll find the offset in `struct
49 reg' where the GDB register REGNUM is stored. Unsupported
50 registers are marked with `-1'. */
51 static int i386bsd_r_reg_offset[] =
52 {
53 REG_OFFSET (r_eax),
54 REG_OFFSET (r_ecx),
55 REG_OFFSET (r_edx),
56 REG_OFFSET (r_ebx),
57 REG_OFFSET (r_esp),
58 REG_OFFSET (r_ebp),
59 REG_OFFSET (r_esi),
60 REG_OFFSET (r_edi),
61 REG_OFFSET (r_eip),
62 REG_OFFSET (r_eflags),
63 REG_OFFSET (r_cs),
64 REG_OFFSET (r_ss),
65 REG_OFFSET (r_ds),
66 REG_OFFSET (r_es),
67 #ifdef HAVE_STRUCT_REG_R_FS
68 REG_OFFSET (r_fs),
69 #else
70 -1,
71 #endif
72 #ifdef HAVE_STRUCT_REG_R_GS
73 REG_OFFSET (r_gs)
74 #else
75 -1
76 #endif
77 };
78
79 /* Macro to determine if a register is fetched with PT_GETREGS. */
80 #define GETREGS_SUPPLIES(regnum) \
81 ((0 <= (regnum) && (regnum) <= 15))
82
83 #ifdef HAVE_PT_GETXMMREGS
84 /* Set to 1 if the kernel supports PT_GETXMMREGS. Initialized to -1
85 so that we try PT_GETXMMREGS the first time around. */
86 static int have_ptrace_xmmregs = -1;
87 #endif
88
89
90 /* Supply the general-purpose registers in GREGS, to REGCACHE. */
91
92 static void
i386bsd_supply_gregset(struct regcache * regcache,const void * gregs)93 i386bsd_supply_gregset (struct regcache *regcache, const void *gregs)
94 {
95 const char *regs = gregs;
96 int regnum;
97
98 for (regnum = 0; regnum < ARRAY_SIZE (i386bsd_r_reg_offset); regnum++)
99 {
100 int offset = i386bsd_r_reg_offset[regnum];
101
102 if (offset != -1)
103 regcache_raw_supply (regcache, regnum, regs + offset);
104 }
105 }
106
107 /* Collect register REGNUM from REGCACHE and store its contents in
108 GREGS. If REGNUM is -1, collect and store all appropriate
109 registers. */
110
111 static void
i386bsd_collect_gregset(const struct regcache * regcache,void * gregs,int regnum)112 i386bsd_collect_gregset (const struct regcache *regcache,
113 void *gregs, int regnum)
114 {
115 char *regs = gregs;
116 int i;
117
118 for (i = 0; i < ARRAY_SIZE (i386bsd_r_reg_offset); i++)
119 {
120 if (regnum == -1 || regnum == i)
121 {
122 int offset = i386bsd_r_reg_offset[i];
123
124 if (offset != -1)
125 regcache_raw_collect (regcache, i, regs + offset);
126 }
127 }
128 }
129
130 /* Fetch register REGNUM from the inferior. If REGNUM is -1, do this
131 for all registers (including the floating point registers). */
132
133 static void
i386bsd_fetch_inferior_registers(int regnum)134 i386bsd_fetch_inferior_registers (int regnum)
135 {
136 int pid;
137
138 /* Cater for systems like OpenBSD, that implement threads as
139 separate processes. */
140 pid = ptid_get_lwp (inferior_ptid);
141 if (pid == 0)
142 pid = ptid_get_pid (inferior_ptid);
143
144 if (regnum == -1 || GETREGS_SUPPLIES (regnum))
145 {
146 struct reg regs;
147
148 if (ptrace (PT_GETREGS, pid, (PTRACE_TYPE_ARG3) ®s, 0) == -1)
149 perror_with_name ("Couldn't get registers");
150
151 i386bsd_supply_gregset (current_regcache, ®s);
152 if (regnum != -1)
153 return;
154 }
155
156 if (regnum == -1 || regnum >= I386_ST0_REGNUM)
157 {
158 struct fpreg fpregs;
159 #ifdef HAVE_PT_GETXMMREGS
160 char xmmregs[512];
161
162 if (have_ptrace_xmmregs != 0
163 && ptrace(PT_GETXMMREGS, pid, (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
164 {
165 have_ptrace_xmmregs = 1;
166 i387_supply_fxsave (current_regcache, -1, xmmregs);
167 }
168 else
169 {
170 if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
171 perror_with_name ("Couldn't get floating point status");
172
173 i387_supply_fsave (current_regcache, -1, &fpregs);
174 }
175 #else
176 if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
177 perror_with_name ("Couldn't get floating point status");
178
179 i387_supply_fsave (current_regcache, -1, &fpregs);
180 #endif
181 }
182 }
183
184 /* Store register REGNUM back into the inferior. If REGNUM is -1, do
185 this for all registers (including the floating point registers). */
186
187 static void
i386bsd_store_inferior_registers(int regnum)188 i386bsd_store_inferior_registers (int regnum)
189 {
190 int pid;
191
192 /* Cater for systems like OpenBSD, that implement threads as
193 separate processes. */
194 pid = ptid_get_lwp (inferior_ptid);
195 if (pid == 0)
196 pid = ptid_get_pid (inferior_ptid);
197
198 if (regnum == -1 || GETREGS_SUPPLIES (regnum))
199 {
200 struct reg regs;
201
202 if (ptrace (PT_GETREGS, pid, (PTRACE_TYPE_ARG3) ®s, 0) == -1)
203 perror_with_name ("Couldn't get registers");
204
205 i386bsd_collect_gregset (current_regcache, ®s, regnum);
206
207 if (ptrace (PT_SETREGS, pid, (PTRACE_TYPE_ARG3) ®s, 0) == -1)
208 perror_with_name ("Couldn't write registers");
209
210 if (regnum != -1)
211 return;
212 }
213
214 if (regnum == -1 || regnum >= I386_ST0_REGNUM)
215 {
216 struct fpreg fpregs;
217 #ifdef HAVE_PT_GETXMMREGS
218 char xmmregs[512];
219
220 if (have_ptrace_xmmregs != 0
221 && ptrace(PT_GETXMMREGS, pid, (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
222 {
223 have_ptrace_xmmregs = 1;
224
225 i387_collect_fxsave (current_regcache, regnum, xmmregs);
226
227 if (ptrace (PT_SETXMMREGS, pid, (PTRACE_TYPE_ARG3) xmmregs, 0) == -1)
228 perror_with_name ("Couldn't write XMM registers");
229 }
230 else
231 {
232 have_ptrace_xmmregs = 0;
233 #endif
234 if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
235 perror_with_name ("Couldn't get floating point status");
236
237 i387_collect_fsave (current_regcache, regnum, &fpregs);
238
239 if (ptrace (PT_SETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
240 perror_with_name ("Couldn't write floating point status");
241 #ifdef HAVE_PT_GETXMMREGS
242 }
243 #endif
244 }
245 }
246
247 /* Create a prototype *BSD/i386 target. The client can override it
248 with local methods. */
249
250 struct target_ops *
i386bsd_target(void)251 i386bsd_target (void)
252 {
253 struct target_ops *t;
254
255 t = inf_ptrace_target ();
256 t->to_fetch_registers = i386bsd_fetch_inferior_registers;
257 t->to_store_registers = i386bsd_store_inferior_registers;
258 return t;
259 }
260
261
262 /* Support for debug registers. */
263
264 #ifdef HAVE_PT_GETDBREGS
265
266 /* Not all versions of FreeBSD/i386 that support the debug registers
267 have this macro. */
268 #ifndef DBREG_DRX
269 #define DBREG_DRX(d, x) ((&d->dr0)[x])
270 #endif
271
272 static void
i386bsd_dr_set(int regnum,unsigned int value)273 i386bsd_dr_set (int regnum, unsigned int value)
274 {
275 struct dbreg dbregs;
276
277 if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
278 (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
279 perror_with_name ("Couldn't get debug registers");
280
281 /* For some mysterious reason, some of the reserved bits in the
282 debug control register get set. Mask these off, otherwise the
283 ptrace call below will fail. */
284 DBREG_DRX ((&dbregs), 7) &= ~(0x0000fc00);
285
286 DBREG_DRX ((&dbregs), regnum) = value;
287
288 if (ptrace (PT_SETDBREGS, PIDGET (inferior_ptid),
289 (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
290 perror_with_name ("Couldn't write debug registers");
291 }
292
293 void
i386bsd_dr_set_control(unsigned long control)294 i386bsd_dr_set_control (unsigned long control)
295 {
296 i386bsd_dr_set (7, control);
297 }
298
299 void
i386bsd_dr_set_addr(int regnum,CORE_ADDR addr)300 i386bsd_dr_set_addr (int regnum, CORE_ADDR addr)
301 {
302 gdb_assert (regnum >= 0 && regnum <= 4);
303
304 i386bsd_dr_set (regnum, addr);
305 }
306
307 void
i386bsd_dr_reset_addr(int regnum)308 i386bsd_dr_reset_addr (int regnum)
309 {
310 gdb_assert (regnum >= 0 && regnum <= 4);
311
312 i386bsd_dr_set (regnum, 0);
313 }
314
315 unsigned long
i386bsd_dr_get_status(void)316 i386bsd_dr_get_status (void)
317 {
318 struct dbreg dbregs;
319
320 /* FIXME: kettenis/2001-03-31: Calling perror_with_name if the
321 ptrace call fails breaks debugging remote targets. The correct
322 way to fix this is to add the hardware breakpoint and watchpoint
323 stuff to the target vector. For now, just return zero if the
324 ptrace call fails. */
325 if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
326 (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
327 #if 0
328 perror_with_name ("Couldn't read debug registers");
329 #else
330 return 0;
331 #endif
332
333 return DBREG_DRX ((&dbregs), 6);
334 }
335
336 #endif /* PT_GETDBREGS */
337
338
339 /* Support for the user struct. */
340
341 /* Return the address register REGNUM. BLOCKEND is the value of
342 u.u_ar0, which should point to the registers. */
343
344 CORE_ADDR
register_u_addr(CORE_ADDR blockend,int regnum)345 register_u_addr (CORE_ADDR blockend, int regnum)
346 {
347 gdb_assert (regnum >= 0 && regnum < ARRAY_SIZE (i386bsd_r_reg_offset));
348
349 return blockend + i386bsd_r_reg_offset[regnum];
350 }
351
352 #include <sys/param.h>
353 #include <sys/user.h>
354
355 /* Return the size of the user struct. */
356
357 int
kernel_u_size(void)358 kernel_u_size (void)
359 {
360 return (sizeof (struct user));
361 }
362
363 void
_initialize_i386bsd_nat(void)364 _initialize_i386bsd_nat (void)
365 {
366 int offset;
367
368 /* To support the recognition of signal handlers, i386bsd-tdep.c
369 hardcodes some constants. Inclusion of this file means that we
370 are compiling a native debugger, which means that we can use the
371 system header files and sysctl(3) to get at the relevant
372 information. */
373
374 #if defined (__FreeBSD_version) && __FreeBSD_version >= 400011
375 #define SC_REG_OFFSET i386fbsd4_sc_reg_offset
376 #elif defined (__FreeBSD_version) && __FreeBSD_version >= 300005
377 #define SC_REG_OFFSET i386fbsd_sc_reg_offset
378 #elif defined (NetBSD) || defined (__NetBSD_Version__)
379 #define SC_REG_OFFSET i386nbsd_sc_reg_offset
380 #elif defined (OpenBSD)
381 #define SC_REG_OFFSET i386obsd_sc_reg_offset
382 #endif
383
384 #ifdef SC_REG_OFFSET
385
386 /* We only check the program counter, stack pointer and frame
387 pointer since these members of `struct sigcontext' are essential
388 for providing backtraces. More checks could be added, but would
389 involve adding configure checks for the appropriate structure
390 members, since older BSD's don't provide all of them. */
391
392 #define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM]
393 #define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM]
394 #define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM]
395
396 /* Override the default value for the offset of the program counter
397 in the sigcontext structure. */
398 offset = offsetof (struct sigcontext, sc_pc);
399
400 if (SC_PC_OFFSET != offset)
401 {
402 warning ("\
403 offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\
404 Please report this to <bug-gdb@gnu.org>.",
405 offset, SC_PC_OFFSET);
406 }
407
408 SC_PC_OFFSET = offset;
409
410 /* Likewise for the stack pointer. */
411 offset = offsetof (struct sigcontext, sc_sp);
412
413 if (SC_SP_OFFSET != offset)
414 {
415 warning ("\
416 offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\
417 Please report this to <bug-gdb@gnu.org>.",
418 offset, SC_SP_OFFSET);
419 }
420
421 SC_SP_OFFSET = offset;
422
423 /* And the frame pointer. */
424 offset = offsetof (struct sigcontext, sc_fp);
425
426 if (SC_FP_OFFSET != offset)
427 {
428 warning ("\
429 offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\
430 Please report this to <bug-gdb@gnu.org>.",
431 offset, SC_FP_OFFSET);
432 }
433
434 SC_FP_OFFSET = offset;
435
436 #endif /* SC_REG_OFFSET */
437 }
438