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1 | /* Native-dependent code for GNU/Linux i386. | |
2 | ||
3 | Copyright 1999, 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 "gdbcore.h" | |
25 | #include "regcache.h" | |
26 | #include "linux-nat.h" | |
27 | ||
28 | #include "gdb_assert.h" | |
29 | #include "gdb_string.h" | |
30 | #include <sys/ptrace.h> | |
31 | #include <sys/user.h> | |
32 | #include <sys/procfs.h> | |
33 | ||
34 | #ifdef HAVE_SYS_REG_H | |
35 | #include <sys/reg.h> | |
36 | #endif | |
37 | ||
38 | #ifndef ORIG_EAX | |
39 | #define ORIG_EAX -1 | |
40 | #endif | |
41 | ||
42 | #ifdef HAVE_SYS_DEBUGREG_H | |
43 | #include <sys/debugreg.h> | |
44 | #endif | |
45 | ||
46 | #ifndef DR_FIRSTADDR | |
47 | #define DR_FIRSTADDR 0 | |
48 | #endif | |
49 | ||
50 | #ifndef DR_LASTADDR | |
51 | #define DR_LASTADDR 3 | |
52 | #endif | |
53 | ||
54 | #ifndef DR_STATUS | |
55 | #define DR_STATUS 6 | |
56 | #endif | |
57 | ||
58 | #ifndef DR_CONTROL | |
59 | #define DR_CONTROL 7 | |
60 | #endif | |
61 | ||
62 | /* Prototypes for supply_gregset etc. */ | |
63 | #include "gregset.h" | |
64 | ||
65 | #include "i387-tdep.h" | |
66 | #include "i386-tdep.h" | |
67 | #include "i386-linux-tdep.h" | |
68 | ||
69 | /* Defines ps_err_e, struct ps_prochandle. */ | |
70 | #include "gdb_proc_service.h" | |
71 | \f | |
72 | ||
73 | /* The register sets used in GNU/Linux ELF core-dumps are identical to | |
74 | the register sets in `struct user' that is used for a.out | |
75 | core-dumps, and is also used by `ptrace'. The corresponding types | |
76 | are `elf_gregset_t' for the general-purpose registers (with | |
77 | `elf_greg_t' the type of a single GP register) and `elf_fpregset_t' | |
78 | for the floating-point registers. | |
79 | ||
80 | Those types used to be available under the names `gregset_t' and | |
81 | `fpregset_t' too, and this file used those names in the past. But | |
82 | those names are now used for the register sets used in the | |
83 | `mcontext_t' type, and have a different size and layout. */ | |
84 | ||
85 | /* Mapping between the general-purpose registers in `struct user' | |
86 | format and GDB's register array layout. */ | |
87 | static int regmap[] = | |
88 | { | |
89 | EAX, ECX, EDX, EBX, | |
90 | UESP, EBP, ESI, EDI, | |
91 | EIP, EFL, CS, SS, | |
92 | DS, ES, FS, GS, | |
93 | -1, -1, -1, -1, /* st0, st1, st2, st3 */ | |
94 | -1, -1, -1, -1, /* st4, st5, st6, st7 */ | |
95 | -1, -1, -1, -1, /* fctrl, fstat, ftag, fiseg */ | |
96 | -1, -1, -1, -1, /* fioff, foseg, fooff, fop */ | |
97 | -1, -1, -1, -1, /* xmm0, xmm1, xmm2, xmm3 */ | |
98 | -1, -1, -1, -1, /* xmm4, xmm5, xmm6, xmm6 */ | |
99 | -1, /* mxcsr */ | |
100 | ORIG_EAX | |
101 | }; | |
102 | ||
103 | /* Which ptrace request retrieves which registers? | |
104 | These apply to the corresponding SET requests as well. */ | |
105 | ||
106 | #define GETREGS_SUPPLIES(regno) \ | |
107 | ((0 <= (regno) && (regno) <= 15) || (regno) == I386_LINUX_ORIG_EAX_REGNUM) | |
108 | ||
109 | #define GETFPXREGS_SUPPLIES(regno) \ | |
110 | (I386_ST0_REGNUM <= (regno) && (regno) < I386_SSE_NUM_REGS) | |
111 | ||
112 | /* Does the current host support the GETREGS request? */ | |
113 | int have_ptrace_getregs = | |
114 | #ifdef HAVE_PTRACE_GETREGS | |
115 | 1 | |
116 | #else | |
117 | 0 | |
118 | #endif | |
119 | ; | |
120 | ||
121 | /* Does the current host support the GETFPXREGS request? The header | |
122 | file may or may not define it, and even if it is defined, the | |
123 | kernel will return EIO if it's running on a pre-SSE processor. | |
124 | ||
125 | My instinct is to attach this to some architecture- or | |
126 | target-specific data structure, but really, a particular GDB | |
127 | process can only run on top of one kernel at a time. So it's okay | |
128 | for this to be a simple variable. */ | |
129 | int have_ptrace_getfpxregs = | |
130 | #ifdef HAVE_PTRACE_GETFPXREGS | |
131 | 1 | |
132 | #else | |
133 | 0 | |
134 | #endif | |
135 | ; | |
136 | \f | |
137 | ||
138 | /* Support for the user struct. */ | |
139 | ||
140 | /* Return the address of register REGNUM. BLOCKEND is the value of | |
141 | u.u_ar0, which should point to the registers. */ | |
142 | ||
143 | CORE_ADDR | |
144 | register_u_addr (CORE_ADDR blockend, int regnum) | |
145 | { | |
146 | return (blockend + 4 * regmap[regnum]); | |
147 | } | |
148 | ||
149 | /* Return the size of the user struct. */ | |
150 | ||
151 | int | |
152 | kernel_u_size (void) | |
153 | { | |
154 | return (sizeof (struct user)); | |
155 | } | |
156 | \f | |
157 | ||
158 | /* Accessing registers through the U area, one at a time. */ | |
159 | ||
160 | /* Fetch one register. */ | |
161 | ||
162 | static void | |
163 | fetch_register (int regno) | |
164 | { | |
165 | int tid; | |
166 | int val; | |
167 | ||
168 | gdb_assert (!have_ptrace_getregs); | |
169 | if (cannot_fetch_register (regno)) | |
170 | { | |
171 | regcache_raw_supply (current_regcache, regno, NULL); | |
172 | return; | |
173 | } | |
174 | ||
175 | /* GNU/Linux LWP ID's are process ID's. */ | |
176 | tid = TIDGET (inferior_ptid); | |
177 | if (tid == 0) | |
178 | tid = PIDGET (inferior_ptid); /* Not a threaded program. */ | |
179 | ||
180 | errno = 0; | |
181 | val = ptrace (PTRACE_PEEKUSER, tid, register_addr (regno, 0), 0); | |
182 | if (errno != 0) | |
183 | error (_("Couldn't read register %s (#%d): %s."), REGISTER_NAME (regno), | |
184 | regno, safe_strerror (errno)); | |
185 | ||
186 | regcache_raw_supply (current_regcache, regno, &val); | |
187 | } | |
188 | ||
189 | /* Store one register. */ | |
190 | ||
191 | static void | |
192 | store_register (int regno) | |
193 | { | |
194 | int tid; | |
195 | int val; | |
196 | ||
197 | gdb_assert (!have_ptrace_getregs); | |
198 | if (cannot_store_register (regno)) | |
199 | return; | |
200 | ||
201 | /* GNU/Linux LWP ID's are process ID's. */ | |
202 | tid = TIDGET (inferior_ptid); | |
203 | if (tid == 0) | |
204 | tid = PIDGET (inferior_ptid); /* Not a threaded program. */ | |
205 | ||
206 | errno = 0; | |
207 | regcache_raw_collect (current_regcache, regno, &val); | |
208 | ptrace (PTRACE_POKEUSER, tid, register_addr (regno, 0), val); | |
209 | if (errno != 0) | |
210 | error (_("Couldn't write register %s (#%d): %s."), REGISTER_NAME (regno), | |
211 | regno, safe_strerror (errno)); | |
212 | } | |
213 | \f | |
214 | ||
215 | /* Transfering the general-purpose registers between GDB, inferiors | |
216 | and core files. */ | |
217 | ||
218 | /* Fill GDB's register array with the general-purpose register values | |
219 | in *GREGSETP. */ | |
220 | ||
221 | void | |
222 | supply_gregset (elf_gregset_t *gregsetp) | |
223 | { | |
224 | elf_greg_t *regp = (elf_greg_t *) gregsetp; | |
225 | int i; | |
226 | ||
227 | for (i = 0; i < I386_NUM_GREGS; i++) | |
228 | regcache_raw_supply (current_regcache, i, regp + regmap[i]); | |
229 | ||
230 | if (I386_LINUX_ORIG_EAX_REGNUM < NUM_REGS) | |
231 | regcache_raw_supply (current_regcache, I386_LINUX_ORIG_EAX_REGNUM, | |
232 | regp + ORIG_EAX); | |
233 | } | |
234 | ||
235 | /* Fill register REGNO (if it is a general-purpose register) in | |
236 | *GREGSETPS with the value in GDB's register array. If REGNO is -1, | |
237 | do this for all registers. */ | |
238 | ||
239 | void | |
240 | fill_gregset (elf_gregset_t *gregsetp, int regno) | |
241 | { | |
242 | elf_greg_t *regp = (elf_greg_t *) gregsetp; | |
243 | int i; | |
244 | ||
245 | for (i = 0; i < I386_NUM_GREGS; i++) | |
246 | if (regno == -1 || regno == i) | |
247 | regcache_raw_collect (current_regcache, i, regp + regmap[i]); | |
248 | ||
249 | if ((regno == -1 || regno == I386_LINUX_ORIG_EAX_REGNUM) | |
250 | && I386_LINUX_ORIG_EAX_REGNUM < NUM_REGS) | |
251 | regcache_raw_collect (current_regcache, I386_LINUX_ORIG_EAX_REGNUM, | |
252 | regp + ORIG_EAX); | |
253 | } | |
254 | ||
255 | #ifdef HAVE_PTRACE_GETREGS | |
256 | ||
257 | /* Fetch all general-purpose registers from process/thread TID and | |
258 | store their values in GDB's register array. */ | |
259 | ||
260 | static void | |
261 | fetch_regs (int tid) | |
262 | { | |
263 | elf_gregset_t regs; | |
264 | ||
265 | if (ptrace (PTRACE_GETREGS, tid, 0, (int) ®s) < 0) | |
266 | { | |
267 | if (errno == EIO) | |
268 | { | |
269 | /* The kernel we're running on doesn't support the GETREGS | |
270 | request. Reset `have_ptrace_getregs'. */ | |
271 | have_ptrace_getregs = 0; | |
272 | return; | |
273 | } | |
274 | ||
275 | perror_with_name ("Couldn't get registers"); | |
276 | } | |
277 | ||
278 | supply_gregset (®s); | |
279 | } | |
280 | ||
281 | /* Store all valid general-purpose registers in GDB's register array | |
282 | into the process/thread specified by TID. */ | |
283 | ||
284 | static void | |
285 | store_regs (int tid, int regno) | |
286 | { | |
287 | elf_gregset_t regs; | |
288 | ||
289 | if (ptrace (PTRACE_GETREGS, tid, 0, (int) ®s) < 0) | |
290 | perror_with_name ("Couldn't get registers"); | |
291 | ||
292 | fill_gregset (®s, regno); | |
293 | ||
294 | if (ptrace (PTRACE_SETREGS, tid, 0, (int) ®s) < 0) | |
295 | perror_with_name ("Couldn't write registers"); | |
296 | } | |
297 | ||
298 | #else | |
299 | ||
300 | static void fetch_regs (int tid) {} | |
301 | static void store_regs (int tid, int regno) {} | |
302 | ||
303 | #endif | |
304 | \f | |
305 | ||
306 | /* Transfering floating-point registers between GDB, inferiors and cores. */ | |
307 | ||
308 | /* Fill GDB's register array with the floating-point register values in | |
309 | *FPREGSETP. */ | |
310 | ||
311 | void | |
312 | supply_fpregset (elf_fpregset_t *fpregsetp) | |
313 | { | |
314 | i387_supply_fsave (current_regcache, -1, fpregsetp); | |
315 | } | |
316 | ||
317 | /* Fill register REGNO (if it is a floating-point register) in | |
318 | *FPREGSETP with the value in GDB's register array. If REGNO is -1, | |
319 | do this for all registers. */ | |
320 | ||
321 | void | |
322 | fill_fpregset (elf_fpregset_t *fpregsetp, int regno) | |
323 | { | |
324 | i387_fill_fsave ((char *) fpregsetp, regno); | |
325 | } | |
326 | ||
327 | #ifdef HAVE_PTRACE_GETREGS | |
328 | ||
329 | /* Fetch all floating-point registers from process/thread TID and store | |
330 | thier values in GDB's register array. */ | |
331 | ||
332 | static void | |
333 | fetch_fpregs (int tid) | |
334 | { | |
335 | elf_fpregset_t fpregs; | |
336 | ||
337 | if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0) | |
338 | perror_with_name ("Couldn't get floating point status"); | |
339 | ||
340 | supply_fpregset (&fpregs); | |
341 | } | |
342 | ||
343 | /* Store all valid floating-point registers in GDB's register array | |
344 | into the process/thread specified by TID. */ | |
345 | ||
346 | static void | |
347 | store_fpregs (int tid, int regno) | |
348 | { | |
349 | elf_fpregset_t fpregs; | |
350 | ||
351 | if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0) | |
352 | perror_with_name ("Couldn't get floating point status"); | |
353 | ||
354 | fill_fpregset (&fpregs, regno); | |
355 | ||
356 | if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0) | |
357 | perror_with_name ("Couldn't write floating point status"); | |
358 | } | |
359 | ||
360 | #else | |
361 | ||
362 | static void fetch_fpregs (int tid) {} | |
363 | static void store_fpregs (int tid, int regno) {} | |
364 | ||
365 | #endif | |
366 | \f | |
367 | ||
368 | /* Transfering floating-point and SSE registers to and from GDB. */ | |
369 | ||
370 | #ifdef HAVE_PTRACE_GETFPXREGS | |
371 | ||
372 | /* Fill GDB's register array with the floating-point and SSE register | |
373 | values in *FPXREGSETP. */ | |
374 | ||
375 | void | |
376 | supply_fpxregset (elf_fpxregset_t *fpxregsetp) | |
377 | { | |
378 | i387_supply_fxsave (current_regcache, -1, fpxregsetp); | |
379 | } | |
380 | ||
381 | /* Fill register REGNO (if it is a floating-point or SSE register) in | |
382 | *FPXREGSETP with the value in GDB's register array. If REGNO is | |
383 | -1, do this for all registers. */ | |
384 | ||
385 | void | |
386 | fill_fpxregset (elf_fpxregset_t *fpxregsetp, int regno) | |
387 | { | |
388 | i387_fill_fxsave ((char *) fpxregsetp, regno); | |
389 | } | |
390 | ||
391 | /* Fetch all registers covered by the PTRACE_GETFPXREGS request from | |
392 | process/thread TID and store their values in GDB's register array. | |
393 | Return non-zero if successful, zero otherwise. */ | |
394 | ||
395 | static int | |
396 | fetch_fpxregs (int tid) | |
397 | { | |
398 | elf_fpxregset_t fpxregs; | |
399 | ||
400 | if (! have_ptrace_getfpxregs) | |
401 | return 0; | |
402 | ||
403 | if (ptrace (PTRACE_GETFPXREGS, tid, 0, (int) &fpxregs) < 0) | |
404 | { | |
405 | if (errno == EIO) | |
406 | { | |
407 | have_ptrace_getfpxregs = 0; | |
408 | return 0; | |
409 | } | |
410 | ||
411 | perror_with_name ("Couldn't read floating-point and SSE registers"); | |
412 | } | |
413 | ||
414 | supply_fpxregset (&fpxregs); | |
415 | return 1; | |
416 | } | |
417 | ||
418 | /* Store all valid registers in GDB's register array covered by the | |
419 | PTRACE_SETFPXREGS request into the process/thread specified by TID. | |
420 | Return non-zero if successful, zero otherwise. */ | |
421 | ||
422 | static int | |
423 | store_fpxregs (int tid, int regno) | |
424 | { | |
425 | elf_fpxregset_t fpxregs; | |
426 | ||
427 | if (! have_ptrace_getfpxregs) | |
428 | return 0; | |
429 | ||
430 | if (ptrace (PTRACE_GETFPXREGS, tid, 0, &fpxregs) == -1) | |
431 | { | |
432 | if (errno == EIO) | |
433 | { | |
434 | have_ptrace_getfpxregs = 0; | |
435 | return 0; | |
436 | } | |
437 | ||
438 | perror_with_name ("Couldn't read floating-point and SSE registers"); | |
439 | } | |
440 | ||
441 | fill_fpxregset (&fpxregs, regno); | |
442 | ||
443 | if (ptrace (PTRACE_SETFPXREGS, tid, 0, &fpxregs) == -1) | |
444 | perror_with_name ("Couldn't write floating-point and SSE registers"); | |
445 | ||
446 | return 1; | |
447 | } | |
448 | ||
449 | #else | |
450 | ||
451 | static int fetch_fpxregs (int tid) { return 0; } | |
452 | static int store_fpxregs (int tid, int regno) { return 0; } | |
453 | ||
454 | #endif /* HAVE_PTRACE_GETFPXREGS */ | |
455 | \f | |
456 | ||
457 | /* Transferring arbitrary registers between GDB and inferior. */ | |
458 | ||
459 | /* Check if register REGNO in the child process is accessible. | |
460 | If we are accessing registers directly via the U area, only the | |
461 | general-purpose registers are available. | |
462 | All registers should be accessible if we have GETREGS support. */ | |
463 | ||
464 | int | |
465 | cannot_fetch_register (int regno) | |
466 | { | |
467 | gdb_assert (regno >= 0 && regno < NUM_REGS); | |
468 | return (!have_ptrace_getregs && regmap[regno] == -1); | |
469 | } | |
470 | ||
471 | int | |
472 | cannot_store_register (int regno) | |
473 | { | |
474 | gdb_assert (regno >= 0 && regno < NUM_REGS); | |
475 | return (!have_ptrace_getregs && regmap[regno] == -1); | |
476 | } | |
477 | ||
478 | /* Fetch register REGNO from the child process. If REGNO is -1, do | |
479 | this for all registers (including the floating point and SSE | |
480 | registers). */ | |
481 | ||
482 | void | |
483 | fetch_inferior_registers (int regno) | |
484 | { | |
485 | int tid; | |
486 | ||
487 | /* Use the old method of peeking around in `struct user' if the | |
488 | GETREGS request isn't available. */ | |
489 | if (!have_ptrace_getregs) | |
490 | { | |
491 | int i; | |
492 | ||
493 | for (i = 0; i < NUM_REGS; i++) | |
494 | if (regno == -1 || regno == i) | |
495 | fetch_register (i); | |
496 | ||
497 | return; | |
498 | } | |
499 | ||
500 | /* GNU/Linux LWP ID's are process ID's. */ | |
501 | tid = TIDGET (inferior_ptid); | |
502 | if (tid == 0) | |
503 | tid = PIDGET (inferior_ptid); /* Not a threaded program. */ | |
504 | ||
505 | /* Use the PTRACE_GETFPXREGS request whenever possible, since it | |
506 | transfers more registers in one system call, and we'll cache the | |
507 | results. But remember that fetch_fpxregs can fail, and return | |
508 | zero. */ | |
509 | if (regno == -1) | |
510 | { | |
511 | fetch_regs (tid); | |
512 | ||
513 | /* The call above might reset `have_ptrace_getregs'. */ | |
514 | if (!have_ptrace_getregs) | |
515 | { | |
516 | fetch_inferior_registers (regno); | |
517 | return; | |
518 | } | |
519 | ||
520 | if (fetch_fpxregs (tid)) | |
521 | return; | |
522 | fetch_fpregs (tid); | |
523 | return; | |
524 | } | |
525 | ||
526 | if (GETREGS_SUPPLIES (regno)) | |
527 | { | |
528 | fetch_regs (tid); | |
529 | return; | |
530 | } | |
531 | ||
532 | if (GETFPXREGS_SUPPLIES (regno)) | |
533 | { | |
534 | if (fetch_fpxregs (tid)) | |
535 | return; | |
536 | ||
537 | /* Either our processor or our kernel doesn't support the SSE | |
538 | registers, so read the FP registers in the traditional way, | |
539 | and fill the SSE registers with dummy values. It would be | |
540 | more graceful to handle differences in the register set using | |
541 | gdbarch. Until then, this will at least make things work | |
542 | plausibly. */ | |
543 | fetch_fpregs (tid); | |
544 | return; | |
545 | } | |
546 | ||
547 | internal_error (__FILE__, __LINE__, | |
548 | "Got request for bad register number %d.", regno); | |
549 | } | |
550 | ||
551 | /* Store register REGNO back into the child process. If REGNO is -1, | |
552 | do this for all registers (including the floating point and SSE | |
553 | registers). */ | |
554 | void | |
555 | store_inferior_registers (int regno) | |
556 | { | |
557 | int tid; | |
558 | ||
559 | /* Use the old method of poking around in `struct user' if the | |
560 | SETREGS request isn't available. */ | |
561 | if (!have_ptrace_getregs) | |
562 | { | |
563 | int i; | |
564 | ||
565 | for (i = 0; i < NUM_REGS; i++) | |
566 | if (regno == -1 || regno == i) | |
567 | store_register (i); | |
568 | ||
569 | return; | |
570 | } | |
571 | ||
572 | /* GNU/Linux LWP ID's are process ID's. */ | |
573 | tid = TIDGET (inferior_ptid); | |
574 | if (tid == 0) | |
575 | tid = PIDGET (inferior_ptid); /* Not a threaded program. */ | |
576 | ||
577 | /* Use the PTRACE_SETFPXREGS requests whenever possible, since it | |
578 | transfers more registers in one system call. But remember that | |
579 | store_fpxregs can fail, and return zero. */ | |
580 | if (regno == -1) | |
581 | { | |
582 | store_regs (tid, regno); | |
583 | if (store_fpxregs (tid, regno)) | |
584 | return; | |
585 | store_fpregs (tid, regno); | |
586 | return; | |
587 | } | |
588 | ||
589 | if (GETREGS_SUPPLIES (regno)) | |
590 | { | |
591 | store_regs (tid, regno); | |
592 | return; | |
593 | } | |
594 | ||
595 | if (GETFPXREGS_SUPPLIES (regno)) | |
596 | { | |
597 | if (store_fpxregs (tid, regno)) | |
598 | return; | |
599 | ||
600 | /* Either our processor or our kernel doesn't support the SSE | |
601 | registers, so just write the FP registers in the traditional | |
602 | way. */ | |
603 | store_fpregs (tid, regno); | |
604 | return; | |
605 | } | |
606 | ||
607 | internal_error (__FILE__, __LINE__, | |
608 | "Got request to store bad register number %d.", regno); | |
609 | } | |
610 | \f | |
611 | ||
612 | /* Support for debug registers. */ | |
613 | ||
614 | static unsigned long | |
615 | i386_linux_dr_get (int regnum) | |
616 | { | |
617 | int tid; | |
618 | unsigned long value; | |
619 | ||
620 | /* FIXME: kettenis/2001-01-29: It's not clear what we should do with | |
621 | multi-threaded processes here. For now, pretend there is just | |
622 | one thread. */ | |
623 | tid = PIDGET (inferior_ptid); | |
624 | ||
625 | /* FIXME: kettenis/2001-03-27: Calling perror_with_name if the | |
626 | ptrace call fails breaks debugging remote targets. The correct | |
627 | way to fix this is to add the hardware breakpoint and watchpoint | |
628 | stuff to the target vector. For now, just return zero if the | |
629 | ptrace call fails. */ | |
630 | errno = 0; | |
631 | value = ptrace (PTRACE_PEEKUSER, tid, | |
632 | offsetof (struct user, u_debugreg[regnum]), 0); | |
633 | if (errno != 0) | |
634 | #if 0 | |
635 | perror_with_name ("Couldn't read debug register"); | |
636 | #else | |
637 | return 0; | |
638 | #endif | |
639 | ||
640 | return value; | |
641 | } | |
642 | ||
643 | static void | |
644 | i386_linux_dr_set (int regnum, unsigned long value) | |
645 | { | |
646 | int tid; | |
647 | ||
648 | /* FIXME: kettenis/2001-01-29: It's not clear what we should do with | |
649 | multi-threaded processes here. For now, pretend there is just | |
650 | one thread. */ | |
651 | tid = PIDGET (inferior_ptid); | |
652 | ||
653 | errno = 0; | |
654 | ptrace (PTRACE_POKEUSER, tid, | |
655 | offsetof (struct user, u_debugreg[regnum]), value); | |
656 | if (errno != 0) | |
657 | perror_with_name ("Couldn't write debug register"); | |
658 | } | |
659 | ||
660 | void | |
661 | i386_linux_dr_set_control (unsigned long control) | |
662 | { | |
663 | i386_linux_dr_set (DR_CONTROL, control); | |
664 | } | |
665 | ||
666 | void | |
667 | i386_linux_dr_set_addr (int regnum, CORE_ADDR addr) | |
668 | { | |
669 | gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR); | |
670 | ||
671 | i386_linux_dr_set (DR_FIRSTADDR + regnum, addr); | |
672 | } | |
673 | ||
674 | void | |
675 | i386_linux_dr_reset_addr (int regnum) | |
676 | { | |
677 | gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR); | |
678 | ||
679 | i386_linux_dr_set (DR_FIRSTADDR + regnum, 0L); | |
680 | } | |
681 | ||
682 | unsigned long | |
683 | i386_linux_dr_get_status (void) | |
684 | { | |
685 | return i386_linux_dr_get (DR_STATUS); | |
686 | } | |
687 | \f | |
688 | ||
689 | /* Called by libthread_db. Returns a pointer to the thread local | |
690 | storage (or its descriptor). */ | |
691 | ||
692 | ps_err_e | |
693 | ps_get_thread_area (const struct ps_prochandle *ph, | |
694 | lwpid_t lwpid, int idx, void **base) | |
695 | { | |
696 | /* NOTE: cagney/2003-08-26: The definition of this buffer is found | |
697 | in the kernel header <asm-i386/ldt.h>. It, after padding, is 4 x | |
698 | 4 byte integers in size: `entry_number', `base_addr', `limit', | |
699 | and a bunch of status bits. | |
700 | ||
701 | The values returned by this ptrace call should be part of the | |
702 | regcache buffer, and ps_get_thread_area should channel its | |
703 | request through the regcache. That way remote targets could | |
704 | provide the value using the remote protocol and not this direct | |
705 | call. | |
706 | ||
707 | Is this function needed? I'm guessing that the `base' is the | |
708 | address of a a descriptor that libthread_db uses to find the | |
709 | thread local address base that GDB needs. Perhaps that | |
710 | descriptor is defined by the ABI. Anyway, given that | |
711 | libthread_db calls this function without prompting (gdb | |
712 | requesting tls base) I guess it needs info in there anyway. */ | |
713 | unsigned int desc[4]; | |
714 | gdb_assert (sizeof (int) == 4); | |
715 | ||
716 | #ifndef PTRACE_GET_THREAD_AREA | |
717 | #define PTRACE_GET_THREAD_AREA 25 | |
718 | #endif | |
719 | ||
720 | if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, | |
721 | (void *) idx, (unsigned long) &desc) < 0) | |
722 | return PS_ERR; | |
723 | ||
724 | *(int *)base = desc[1]; | |
725 | return PS_OK; | |
726 | } | |
727 | \f | |
728 | ||
729 | /* The instruction for a GNU/Linux system call is: | |
730 | int $0x80 | |
731 | or 0xcd 0x80. */ | |
732 | ||
733 | static const unsigned char linux_syscall[] = { 0xcd, 0x80 }; | |
734 | ||
735 | #define LINUX_SYSCALL_LEN (sizeof linux_syscall) | |
736 | ||
737 | /* The system call number is stored in the %eax register. */ | |
738 | #define LINUX_SYSCALL_REGNUM I386_EAX_REGNUM | |
739 | ||
740 | /* We are specifically interested in the sigreturn and rt_sigreturn | |
741 | system calls. */ | |
742 | ||
743 | #ifndef SYS_sigreturn | |
744 | #define SYS_sigreturn 0x77 | |
745 | #endif | |
746 | #ifndef SYS_rt_sigreturn | |
747 | #define SYS_rt_sigreturn 0xad | |
748 | #endif | |
749 | ||
750 | /* Offset to saved processor flags, from <asm/sigcontext.h>. */ | |
751 | #define LINUX_SIGCONTEXT_EFLAGS_OFFSET (64) | |
752 | ||
753 | /* Resume execution of the inferior process. | |
754 | If STEP is nonzero, single-step it. | |
755 | If SIGNAL is nonzero, give it that signal. */ | |
756 | ||
757 | void | |
758 | child_resume (ptid_t ptid, int step, enum target_signal signal) | |
759 | { | |
760 | int pid = PIDGET (ptid); | |
761 | ||
762 | int request = PTRACE_CONT; | |
763 | ||
764 | if (pid == -1) | |
765 | /* Resume all threads. */ | |
766 | /* I think this only gets used in the non-threaded case, where "resume | |
767 | all threads" and "resume inferior_ptid" are the same. */ | |
768 | pid = PIDGET (inferior_ptid); | |
769 | ||
770 | if (step) | |
771 | { | |
772 | CORE_ADDR pc = read_pc_pid (pid_to_ptid (pid)); | |
773 | unsigned char buf[LINUX_SYSCALL_LEN]; | |
774 | ||
775 | request = PTRACE_SINGLESTEP; | |
776 | ||
777 | /* Returning from a signal trampoline is done by calling a | |
778 | special system call (sigreturn or rt_sigreturn, see | |
779 | i386-linux-tdep.c for more information). This system call | |
780 | restores the registers that were saved when the signal was | |
781 | raised, including %eflags. That means that single-stepping | |
782 | won't work. Instead, we'll have to modify the signal context | |
783 | that's about to be restored, and set the trace flag there. */ | |
784 | ||
785 | /* First check if PC is at a system call. */ | |
786 | if (deprecated_read_memory_nobpt (pc, (char *) buf, LINUX_SYSCALL_LEN) == 0 | |
787 | && memcmp (buf, linux_syscall, LINUX_SYSCALL_LEN) == 0) | |
788 | { | |
789 | int syscall = read_register_pid (LINUX_SYSCALL_REGNUM, | |
790 | pid_to_ptid (pid)); | |
791 | ||
792 | /* Then check the system call number. */ | |
793 | if (syscall == SYS_sigreturn || syscall == SYS_rt_sigreturn) | |
794 | { | |
795 | CORE_ADDR sp = read_register (I386_ESP_REGNUM); | |
796 | CORE_ADDR addr = sp; | |
797 | unsigned long int eflags; | |
798 | ||
799 | if (syscall == SYS_rt_sigreturn) | |
800 | addr = read_memory_integer (sp + 8, 4) + 20; | |
801 | ||
802 | /* Set the trace flag in the context that's about to be | |
803 | restored. */ | |
804 | addr += LINUX_SIGCONTEXT_EFLAGS_OFFSET; | |
805 | read_memory (addr, (char *) &eflags, 4); | |
806 | eflags |= 0x0100; | |
807 | write_memory (addr, (char *) &eflags, 4); | |
808 | } | |
809 | } | |
810 | } | |
811 | ||
812 | if (ptrace (request, pid, 0, target_signal_to_host (signal)) == -1) | |
813 | perror_with_name ("ptrace"); | |
814 | } | |
815 | ||
816 | void | |
817 | child_post_startup_inferior (ptid_t ptid) | |
818 | { | |
819 | i386_cleanup_dregs (); | |
820 | linux_child_post_startup_inferior (ptid); | |
821 | } |