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1 | /* Native-dependent code for GNU/Linux i386. | |
2 | ||
3 | Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 | |
4 | Free Software Foundation, Inc. | |
5 | ||
6 | This file is part of GDB. | |
7 | ||
8 | This program is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 2 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | This program is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with this program; if not, write to the Free Software | |
20 | Foundation, Inc., 51 Franklin Street, Fifth Floor, | |
21 | Boston, MA 02110-1301, USA. */ | |
22 | ||
23 | #include "defs.h" | |
24 | #include "inferior.h" | |
25 | #include "gdbcore.h" | |
26 | #include "regcache.h" | |
27 | #include "target.h" | |
28 | #include "linux-nat.h" | |
29 | ||
30 | #include "gdb_assert.h" | |
31 | #include "gdb_string.h" | |
32 | #include <sys/ptrace.h> | |
33 | #include <sys/user.h> | |
34 | #include <sys/procfs.h> | |
35 | ||
36 | #ifdef HAVE_SYS_REG_H | |
37 | #include <sys/reg.h> | |
38 | #endif | |
39 | ||
40 | #ifndef ORIG_EAX | |
41 | #define ORIG_EAX -1 | |
42 | #endif | |
43 | ||
44 | #ifdef HAVE_SYS_DEBUGREG_H | |
45 | #include <sys/debugreg.h> | |
46 | #endif | |
47 | ||
48 | #ifndef DR_FIRSTADDR | |
49 | #define DR_FIRSTADDR 0 | |
50 | #endif | |
51 | ||
52 | #ifndef DR_LASTADDR | |
53 | #define DR_LASTADDR 3 | |
54 | #endif | |
55 | ||
56 | #ifndef DR_STATUS | |
57 | #define DR_STATUS 6 | |
58 | #endif | |
59 | ||
60 | #ifndef DR_CONTROL | |
61 | #define DR_CONTROL 7 | |
62 | #endif | |
63 | ||
64 | /* Prototypes for supply_gregset etc. */ | |
65 | #include "gregset.h" | |
66 | ||
67 | #include "i387-tdep.h" | |
68 | #include "i386-tdep.h" | |
69 | #include "i386-linux-tdep.h" | |
70 | ||
71 | /* Defines ps_err_e, struct ps_prochandle. */ | |
72 | #include "gdb_proc_service.h" | |
73 | \f | |
74 | ||
75 | /* The register sets used in GNU/Linux ELF core-dumps are identical to | |
76 | the register sets in `struct user' that is used for a.out | |
77 | core-dumps, and is also used by `ptrace'. The corresponding types | |
78 | are `elf_gregset_t' for the general-purpose registers (with | |
79 | `elf_greg_t' the type of a single GP register) and `elf_fpregset_t' | |
80 | for the floating-point registers. | |
81 | ||
82 | Those types used to be available under the names `gregset_t' and | |
83 | `fpregset_t' too, and this file used those names in the past. But | |
84 | those names are now used for the register sets used in the | |
85 | `mcontext_t' type, and have a different size and layout. */ | |
86 | ||
87 | /* Mapping between the general-purpose registers in `struct user' | |
88 | format and GDB's register array layout. */ | |
89 | static int regmap[] = | |
90 | { | |
91 | EAX, ECX, EDX, EBX, | |
92 | UESP, EBP, ESI, EDI, | |
93 | EIP, EFL, CS, SS, | |
94 | DS, ES, FS, GS, | |
95 | -1, -1, -1, -1, /* st0, st1, st2, st3 */ | |
96 | -1, -1, -1, -1, /* st4, st5, st6, st7 */ | |
97 | -1, -1, -1, -1, /* fctrl, fstat, ftag, fiseg */ | |
98 | -1, -1, -1, -1, /* fioff, foseg, fooff, fop */ | |
99 | -1, -1, -1, -1, /* xmm0, xmm1, xmm2, xmm3 */ | |
100 | -1, -1, -1, -1, /* xmm4, xmm5, xmm6, xmm6 */ | |
101 | -1, /* mxcsr */ | |
102 | ORIG_EAX | |
103 | }; | |
104 | ||
105 | /* Which ptrace request retrieves which registers? | |
106 | These apply to the corresponding SET requests as well. */ | |
107 | ||
108 | #define GETREGS_SUPPLIES(regno) \ | |
109 | ((0 <= (regno) && (regno) <= 15) || (regno) == I386_LINUX_ORIG_EAX_REGNUM) | |
110 | ||
111 | #define GETFPXREGS_SUPPLIES(regno) \ | |
112 | (I386_ST0_REGNUM <= (regno) && (regno) < I386_SSE_NUM_REGS) | |
113 | ||
114 | /* Does the current host support the GETREGS request? */ | |
115 | int have_ptrace_getregs = | |
116 | #ifdef HAVE_PTRACE_GETREGS | |
117 | 1 | |
118 | #else | |
119 | 0 | |
120 | #endif | |
121 | ; | |
122 | ||
123 | /* Does the current host support the GETFPXREGS request? The header | |
124 | file may or may not define it, and even if it is defined, the | |
125 | kernel will return EIO if it's running on a pre-SSE processor. | |
126 | ||
127 | My instinct is to attach this to some architecture- or | |
128 | target-specific data structure, but really, a particular GDB | |
129 | process can only run on top of one kernel at a time. So it's okay | |
130 | for this to be a simple variable. */ | |
131 | int have_ptrace_getfpxregs = | |
132 | #ifdef HAVE_PTRACE_GETFPXREGS | |
133 | 1 | |
134 | #else | |
135 | 0 | |
136 | #endif | |
137 | ; | |
138 | \f | |
139 | ||
140 | /* Accessing registers through the U area, one at a time. */ | |
141 | ||
142 | /* Fetch one register. */ | |
143 | ||
144 | static void | |
145 | fetch_register (struct regcache *regcache, int regno) | |
146 | { | |
147 | int tid; | |
148 | int val; | |
149 | ||
150 | gdb_assert (!have_ptrace_getregs); | |
151 | if (regmap[regno] == -1) | |
152 | { | |
153 | regcache_raw_supply (regcache, regno, NULL); | |
154 | return; | |
155 | } | |
156 | ||
157 | /* GNU/Linux LWP ID's are process ID's. */ | |
158 | tid = TIDGET (inferior_ptid); | |
159 | if (tid == 0) | |
160 | tid = PIDGET (inferior_ptid); /* Not a threaded program. */ | |
161 | ||
162 | errno = 0; | |
163 | val = ptrace (PTRACE_PEEKUSER, tid, 4 * regmap[regno], 0); | |
164 | if (errno != 0) | |
165 | error (_("Couldn't read register %s (#%d): %s."), REGISTER_NAME (regno), | |
166 | regno, safe_strerror (errno)); | |
167 | ||
168 | regcache_raw_supply (regcache, regno, &val); | |
169 | } | |
170 | ||
171 | /* Store one register. */ | |
172 | ||
173 | static void | |
174 | store_register (const struct regcache *regcache, int regno) | |
175 | { | |
176 | int tid; | |
177 | int val; | |
178 | ||
179 | gdb_assert (!have_ptrace_getregs); | |
180 | if (regmap[regno] == -1) | |
181 | return; | |
182 | ||
183 | /* GNU/Linux LWP ID's are process ID's. */ | |
184 | tid = TIDGET (inferior_ptid); | |
185 | if (tid == 0) | |
186 | tid = PIDGET (inferior_ptid); /* Not a threaded program. */ | |
187 | ||
188 | errno = 0; | |
189 | regcache_raw_collect (regcache, regno, &val); | |
190 | ptrace (PTRACE_POKEUSER, tid, 4 * regmap[regno], val); | |
191 | if (errno != 0) | |
192 | error (_("Couldn't write register %s (#%d): %s."), REGISTER_NAME (regno), | |
193 | regno, safe_strerror (errno)); | |
194 | } | |
195 | \f | |
196 | ||
197 | /* Transfering the general-purpose registers between GDB, inferiors | |
198 | and core files. */ | |
199 | ||
200 | /* Fill GDB's register array with the general-purpose register values | |
201 | in *GREGSETP. */ | |
202 | ||
203 | void | |
204 | supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp) | |
205 | { | |
206 | const elf_greg_t *regp = (const elf_greg_t *) gregsetp; | |
207 | int i; | |
208 | ||
209 | for (i = 0; i < I386_NUM_GREGS; i++) | |
210 | regcache_raw_supply (regcache, i, regp + regmap[i]); | |
211 | ||
212 | if (I386_LINUX_ORIG_EAX_REGNUM < NUM_REGS) | |
213 | regcache_raw_supply (regcache, I386_LINUX_ORIG_EAX_REGNUM, | |
214 | regp + ORIG_EAX); | |
215 | } | |
216 | ||
217 | /* Fill register REGNO (if it is a general-purpose register) in | |
218 | *GREGSETPS with the value in GDB's register array. If REGNO is -1, | |
219 | do this for all registers. */ | |
220 | ||
221 | void | |
222 | fill_gregset (const struct regcache *regcache, | |
223 | elf_gregset_t *gregsetp, int regno) | |
224 | { | |
225 | elf_greg_t *regp = (elf_greg_t *) gregsetp; | |
226 | int i; | |
227 | ||
228 | for (i = 0; i < I386_NUM_GREGS; i++) | |
229 | if (regno == -1 || regno == i) | |
230 | regcache_raw_collect (regcache, i, regp + regmap[i]); | |
231 | ||
232 | if ((regno == -1 || regno == I386_LINUX_ORIG_EAX_REGNUM) | |
233 | && I386_LINUX_ORIG_EAX_REGNUM < NUM_REGS) | |
234 | regcache_raw_collect (regcache, I386_LINUX_ORIG_EAX_REGNUM, | |
235 | regp + ORIG_EAX); | |
236 | } | |
237 | ||
238 | #ifdef HAVE_PTRACE_GETREGS | |
239 | ||
240 | /* Fetch all general-purpose registers from process/thread TID and | |
241 | store their values in GDB's register array. */ | |
242 | ||
243 | static void | |
244 | fetch_regs (struct regcache *regcache, int tid) | |
245 | { | |
246 | elf_gregset_t regs; | |
247 | ||
248 | if (ptrace (PTRACE_GETREGS, tid, 0, (int) ®s) < 0) | |
249 | { | |
250 | if (errno == EIO) | |
251 | { | |
252 | /* The kernel we're running on doesn't support the GETREGS | |
253 | request. Reset `have_ptrace_getregs'. */ | |
254 | have_ptrace_getregs = 0; | |
255 | return; | |
256 | } | |
257 | ||
258 | perror_with_name (_("Couldn't get registers")); | |
259 | } | |
260 | ||
261 | supply_gregset (regcache, (const elf_gregset_t *) ®s); | |
262 | } | |
263 | ||
264 | /* Store all valid general-purpose registers in GDB's register array | |
265 | into the process/thread specified by TID. */ | |
266 | ||
267 | static void | |
268 | store_regs (const struct regcache *regcache, int tid, int regno) | |
269 | { | |
270 | elf_gregset_t regs; | |
271 | ||
272 | if (ptrace (PTRACE_GETREGS, tid, 0, (int) ®s) < 0) | |
273 | perror_with_name (_("Couldn't get registers")); | |
274 | ||
275 | fill_gregset (regcache, ®s, regno); | |
276 | ||
277 | if (ptrace (PTRACE_SETREGS, tid, 0, (int) ®s) < 0) | |
278 | perror_with_name (_("Couldn't write registers")); | |
279 | } | |
280 | ||
281 | #else | |
282 | ||
283 | static void fetch_regs (struct regcache *regcache, int tid) {} | |
284 | static void store_regs (const struct regcache *regcache, int tid, int regno) {} | |
285 | ||
286 | #endif | |
287 | \f | |
288 | ||
289 | /* Transfering floating-point registers between GDB, inferiors and cores. */ | |
290 | ||
291 | /* Fill GDB's register array with the floating-point register values in | |
292 | *FPREGSETP. */ | |
293 | ||
294 | void | |
295 | supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp) | |
296 | { | |
297 | i387_supply_fsave (regcache, -1, fpregsetp); | |
298 | } | |
299 | ||
300 | /* Fill register REGNO (if it is a floating-point register) in | |
301 | *FPREGSETP with the value in GDB's register array. If REGNO is -1, | |
302 | do this for all registers. */ | |
303 | ||
304 | void | |
305 | fill_fpregset (const struct regcache *regcache, | |
306 | elf_fpregset_t *fpregsetp, int regno) | |
307 | { | |
308 | i387_collect_fsave (regcache, regno, fpregsetp); | |
309 | } | |
310 | ||
311 | #ifdef HAVE_PTRACE_GETREGS | |
312 | ||
313 | /* Fetch all floating-point registers from process/thread TID and store | |
314 | thier values in GDB's register array. */ | |
315 | ||
316 | static void | |
317 | fetch_fpregs (struct regcache *regcache, int tid) | |
318 | { | |
319 | elf_fpregset_t fpregs; | |
320 | ||
321 | if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0) | |
322 | perror_with_name (_("Couldn't get floating point status")); | |
323 | ||
324 | supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs); | |
325 | } | |
326 | ||
327 | /* Store all valid floating-point registers in GDB's register array | |
328 | into the process/thread specified by TID. */ | |
329 | ||
330 | static void | |
331 | store_fpregs (const struct regcache *regcache, int tid, int regno) | |
332 | { | |
333 | elf_fpregset_t fpregs; | |
334 | ||
335 | if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0) | |
336 | perror_with_name (_("Couldn't get floating point status")); | |
337 | ||
338 | fill_fpregset (regcache, &fpregs, regno); | |
339 | ||
340 | if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0) | |
341 | perror_with_name (_("Couldn't write floating point status")); | |
342 | } | |
343 | ||
344 | #else | |
345 | ||
346 | static void fetch_fpregs (struct regcache *regcache, int tid) {} | |
347 | static void store_fpregs (const struct regcache *regcache, int tid, int regno) {} | |
348 | ||
349 | #endif | |
350 | \f | |
351 | ||
352 | /* Transfering floating-point and SSE registers to and from GDB. */ | |
353 | ||
354 | #ifdef HAVE_PTRACE_GETFPXREGS | |
355 | ||
356 | /* Fill GDB's register array with the floating-point and SSE register | |
357 | values in *FPXREGSETP. */ | |
358 | ||
359 | void | |
360 | supply_fpxregset (struct regcache *regcache, | |
361 | const elf_fpxregset_t *fpxregsetp) | |
362 | { | |
363 | i387_supply_fxsave (regcache, -1, fpxregsetp); | |
364 | } | |
365 | ||
366 | /* Fill register REGNO (if it is a floating-point or SSE register) in | |
367 | *FPXREGSETP with the value in GDB's register array. If REGNO is | |
368 | -1, do this for all registers. */ | |
369 | ||
370 | void | |
371 | fill_fpxregset (const struct regcache *regcache, | |
372 | elf_fpxregset_t *fpxregsetp, int regno) | |
373 | { | |
374 | i387_collect_fxsave (regcache, regno, fpxregsetp); | |
375 | } | |
376 | ||
377 | /* Fetch all registers covered by the PTRACE_GETFPXREGS request from | |
378 | process/thread TID and store their values in GDB's register array. | |
379 | Return non-zero if successful, zero otherwise. */ | |
380 | ||
381 | static int | |
382 | fetch_fpxregs (struct regcache *regcache, int tid) | |
383 | { | |
384 | elf_fpxregset_t fpxregs; | |
385 | ||
386 | if (! have_ptrace_getfpxregs) | |
387 | return 0; | |
388 | ||
389 | if (ptrace (PTRACE_GETFPXREGS, tid, 0, (int) &fpxregs) < 0) | |
390 | { | |
391 | if (errno == EIO) | |
392 | { | |
393 | have_ptrace_getfpxregs = 0; | |
394 | return 0; | |
395 | } | |
396 | ||
397 | perror_with_name (_("Couldn't read floating-point and SSE registers")); | |
398 | } | |
399 | ||
400 | supply_fpxregset (regcache, (const elf_fpxregset_t *) &fpxregs); | |
401 | return 1; | |
402 | } | |
403 | ||
404 | /* Store all valid registers in GDB's register array covered by the | |
405 | PTRACE_SETFPXREGS request into the process/thread specified by TID. | |
406 | Return non-zero if successful, zero otherwise. */ | |
407 | ||
408 | static int | |
409 | store_fpxregs (const struct regcache *regcache, int tid, int regno) | |
410 | { | |
411 | elf_fpxregset_t fpxregs; | |
412 | ||
413 | if (! have_ptrace_getfpxregs) | |
414 | return 0; | |
415 | ||
416 | if (ptrace (PTRACE_GETFPXREGS, tid, 0, &fpxregs) == -1) | |
417 | { | |
418 | if (errno == EIO) | |
419 | { | |
420 | have_ptrace_getfpxregs = 0; | |
421 | return 0; | |
422 | } | |
423 | ||
424 | perror_with_name (_("Couldn't read floating-point and SSE registers")); | |
425 | } | |
426 | ||
427 | fill_fpxregset (regcache, &fpxregs, regno); | |
428 | ||
429 | if (ptrace (PTRACE_SETFPXREGS, tid, 0, &fpxregs) == -1) | |
430 | perror_with_name (_("Couldn't write floating-point and SSE registers")); | |
431 | ||
432 | return 1; | |
433 | } | |
434 | ||
435 | #else | |
436 | ||
437 | static int fetch_fpxregs (struct regcache *regcache, int tid) { return 0; } | |
438 | static int store_fpxregs (const struct regcache *regcache, int tid, int regno) { return 0; } | |
439 | ||
440 | #endif /* HAVE_PTRACE_GETFPXREGS */ | |
441 | \f | |
442 | ||
443 | /* Transferring arbitrary registers between GDB and inferior. */ | |
444 | ||
445 | /* Fetch register REGNO from the child process. If REGNO is -1, do | |
446 | this for all registers (including the floating point and SSE | |
447 | registers). */ | |
448 | ||
449 | static void | |
450 | i386_linux_fetch_inferior_registers (struct regcache *regcache, int regno) | |
451 | { | |
452 | int tid; | |
453 | ||
454 | /* Use the old method of peeking around in `struct user' if the | |
455 | GETREGS request isn't available. */ | |
456 | if (!have_ptrace_getregs) | |
457 | { | |
458 | int i; | |
459 | ||
460 | for (i = 0; i < NUM_REGS; i++) | |
461 | if (regno == -1 || regno == i) | |
462 | fetch_register (regcache, i); | |
463 | ||
464 | return; | |
465 | } | |
466 | ||
467 | /* GNU/Linux LWP ID's are process ID's. */ | |
468 | tid = TIDGET (inferior_ptid); | |
469 | if (tid == 0) | |
470 | tid = PIDGET (inferior_ptid); /* Not a threaded program. */ | |
471 | ||
472 | /* Use the PTRACE_GETFPXREGS request whenever possible, since it | |
473 | transfers more registers in one system call, and we'll cache the | |
474 | results. But remember that fetch_fpxregs can fail, and return | |
475 | zero. */ | |
476 | if (regno == -1) | |
477 | { | |
478 | fetch_regs (regcache, tid); | |
479 | ||
480 | /* The call above might reset `have_ptrace_getregs'. */ | |
481 | if (!have_ptrace_getregs) | |
482 | { | |
483 | i386_linux_fetch_inferior_registers (regcache, regno); | |
484 | return; | |
485 | } | |
486 | ||
487 | if (fetch_fpxregs (regcache, tid)) | |
488 | return; | |
489 | fetch_fpregs (regcache, tid); | |
490 | return; | |
491 | } | |
492 | ||
493 | if (GETREGS_SUPPLIES (regno)) | |
494 | { | |
495 | fetch_regs (regcache, tid); | |
496 | return; | |
497 | } | |
498 | ||
499 | if (GETFPXREGS_SUPPLIES (regno)) | |
500 | { | |
501 | if (fetch_fpxregs (regcache, tid)) | |
502 | return; | |
503 | ||
504 | /* Either our processor or our kernel doesn't support the SSE | |
505 | registers, so read the FP registers in the traditional way, | |
506 | and fill the SSE registers with dummy values. It would be | |
507 | more graceful to handle differences in the register set using | |
508 | gdbarch. Until then, this will at least make things work | |
509 | plausibly. */ | |
510 | fetch_fpregs (regcache, tid); | |
511 | return; | |
512 | } | |
513 | ||
514 | internal_error (__FILE__, __LINE__, | |
515 | _("Got request for bad register number %d."), regno); | |
516 | } | |
517 | ||
518 | /* Store register REGNO back into the child process. If REGNO is -1, | |
519 | do this for all registers (including the floating point and SSE | |
520 | registers). */ | |
521 | static void | |
522 | i386_linux_store_inferior_registers (struct regcache *regcache, int regno) | |
523 | { | |
524 | int tid; | |
525 | ||
526 | /* Use the old method of poking around in `struct user' if the | |
527 | SETREGS request isn't available. */ | |
528 | if (!have_ptrace_getregs) | |
529 | { | |
530 | int i; | |
531 | ||
532 | for (i = 0; i < NUM_REGS; i++) | |
533 | if (regno == -1 || regno == i) | |
534 | store_register (regcache, i); | |
535 | ||
536 | return; | |
537 | } | |
538 | ||
539 | /* GNU/Linux LWP ID's are process ID's. */ | |
540 | tid = TIDGET (inferior_ptid); | |
541 | if (tid == 0) | |
542 | tid = PIDGET (inferior_ptid); /* Not a threaded program. */ | |
543 | ||
544 | /* Use the PTRACE_SETFPXREGS requests whenever possible, since it | |
545 | transfers more registers in one system call. But remember that | |
546 | store_fpxregs can fail, and return zero. */ | |
547 | if (regno == -1) | |
548 | { | |
549 | store_regs (regcache, tid, regno); | |
550 | if (store_fpxregs (regcache, tid, regno)) | |
551 | return; | |
552 | store_fpregs (regcache, tid, regno); | |
553 | return; | |
554 | } | |
555 | ||
556 | if (GETREGS_SUPPLIES (regno)) | |
557 | { | |
558 | store_regs (regcache, tid, regno); | |
559 | return; | |
560 | } | |
561 | ||
562 | if (GETFPXREGS_SUPPLIES (regno)) | |
563 | { | |
564 | if (store_fpxregs (regcache, tid, regno)) | |
565 | return; | |
566 | ||
567 | /* Either our processor or our kernel doesn't support the SSE | |
568 | registers, so just write the FP registers in the traditional | |
569 | way. */ | |
570 | store_fpregs (regcache, tid, regno); | |
571 | return; | |
572 | } | |
573 | ||
574 | internal_error (__FILE__, __LINE__, | |
575 | _("Got request to store bad register number %d."), regno); | |
576 | } | |
577 | \f | |
578 | ||
579 | /* Support for debug registers. */ | |
580 | ||
581 | static unsigned long | |
582 | i386_linux_dr_get (int regnum) | |
583 | { | |
584 | int tid; | |
585 | unsigned long value; | |
586 | ||
587 | /* FIXME: kettenis/2001-01-29: It's not clear what we should do with | |
588 | multi-threaded processes here. For now, pretend there is just | |
589 | one thread. */ | |
590 | tid = PIDGET (inferior_ptid); | |
591 | ||
592 | /* FIXME: kettenis/2001-03-27: Calling perror_with_name if the | |
593 | ptrace call fails breaks debugging remote targets. The correct | |
594 | way to fix this is to add the hardware breakpoint and watchpoint | |
595 | stuff to the target vector. For now, just return zero if the | |
596 | ptrace call fails. */ | |
597 | errno = 0; | |
598 | value = ptrace (PTRACE_PEEKUSER, tid, | |
599 | offsetof (struct user, u_debugreg[regnum]), 0); | |
600 | if (errno != 0) | |
601 | #if 0 | |
602 | perror_with_name (_("Couldn't read debug register")); | |
603 | #else | |
604 | return 0; | |
605 | #endif | |
606 | ||
607 | return value; | |
608 | } | |
609 | ||
610 | static void | |
611 | i386_linux_dr_set (int regnum, unsigned long value) | |
612 | { | |
613 | int tid; | |
614 | ||
615 | /* FIXME: kettenis/2001-01-29: It's not clear what we should do with | |
616 | multi-threaded processes here. For now, pretend there is just | |
617 | one thread. */ | |
618 | tid = PIDGET (inferior_ptid); | |
619 | ||
620 | errno = 0; | |
621 | ptrace (PTRACE_POKEUSER, tid, | |
622 | offsetof (struct user, u_debugreg[regnum]), value); | |
623 | if (errno != 0) | |
624 | perror_with_name (_("Couldn't write debug register")); | |
625 | } | |
626 | ||
627 | void | |
628 | i386_linux_dr_set_control (unsigned long control) | |
629 | { | |
630 | i386_linux_dr_set (DR_CONTROL, control); | |
631 | } | |
632 | ||
633 | void | |
634 | i386_linux_dr_set_addr (int regnum, CORE_ADDR addr) | |
635 | { | |
636 | gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR); | |
637 | ||
638 | i386_linux_dr_set (DR_FIRSTADDR + regnum, addr); | |
639 | } | |
640 | ||
641 | void | |
642 | i386_linux_dr_reset_addr (int regnum) | |
643 | { | |
644 | gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR); | |
645 | ||
646 | i386_linux_dr_set (DR_FIRSTADDR + regnum, 0L); | |
647 | } | |
648 | ||
649 | unsigned long | |
650 | i386_linux_dr_get_status (void) | |
651 | { | |
652 | return i386_linux_dr_get (DR_STATUS); | |
653 | } | |
654 | \f | |
655 | ||
656 | /* Called by libthread_db. Returns a pointer to the thread local | |
657 | storage (or its descriptor). */ | |
658 | ||
659 | ps_err_e | |
660 | ps_get_thread_area (const struct ps_prochandle *ph, | |
661 | lwpid_t lwpid, int idx, void **base) | |
662 | { | |
663 | /* NOTE: cagney/2003-08-26: The definition of this buffer is found | |
664 | in the kernel header <asm-i386/ldt.h>. It, after padding, is 4 x | |
665 | 4 byte integers in size: `entry_number', `base_addr', `limit', | |
666 | and a bunch of status bits. | |
667 | ||
668 | The values returned by this ptrace call should be part of the | |
669 | regcache buffer, and ps_get_thread_area should channel its | |
670 | request through the regcache. That way remote targets could | |
671 | provide the value using the remote protocol and not this direct | |
672 | call. | |
673 | ||
674 | Is this function needed? I'm guessing that the `base' is the | |
675 | address of a a descriptor that libthread_db uses to find the | |
676 | thread local address base that GDB needs. Perhaps that | |
677 | descriptor is defined by the ABI. Anyway, given that | |
678 | libthread_db calls this function without prompting (gdb | |
679 | requesting tls base) I guess it needs info in there anyway. */ | |
680 | unsigned int desc[4]; | |
681 | gdb_assert (sizeof (int) == 4); | |
682 | ||
683 | #ifndef PTRACE_GET_THREAD_AREA | |
684 | #define PTRACE_GET_THREAD_AREA 25 | |
685 | #endif | |
686 | ||
687 | if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, | |
688 | (void *) idx, (unsigned long) &desc) < 0) | |
689 | return PS_ERR; | |
690 | ||
691 | *(int *)base = desc[1]; | |
692 | return PS_OK; | |
693 | } | |
694 | \f | |
695 | ||
696 | /* The instruction for a GNU/Linux system call is: | |
697 | int $0x80 | |
698 | or 0xcd 0x80. */ | |
699 | ||
700 | static const unsigned char linux_syscall[] = { 0xcd, 0x80 }; | |
701 | ||
702 | #define LINUX_SYSCALL_LEN (sizeof linux_syscall) | |
703 | ||
704 | /* The system call number is stored in the %eax register. */ | |
705 | #define LINUX_SYSCALL_REGNUM I386_EAX_REGNUM | |
706 | ||
707 | /* We are specifically interested in the sigreturn and rt_sigreturn | |
708 | system calls. */ | |
709 | ||
710 | #ifndef SYS_sigreturn | |
711 | #define SYS_sigreturn 0x77 | |
712 | #endif | |
713 | #ifndef SYS_rt_sigreturn | |
714 | #define SYS_rt_sigreturn 0xad | |
715 | #endif | |
716 | ||
717 | /* Offset to saved processor flags, from <asm/sigcontext.h>. */ | |
718 | #define LINUX_SIGCONTEXT_EFLAGS_OFFSET (64) | |
719 | ||
720 | /* Resume execution of the inferior process. | |
721 | If STEP is nonzero, single-step it. | |
722 | If SIGNAL is nonzero, give it that signal. */ | |
723 | ||
724 | static void | |
725 | i386_linux_resume (ptid_t ptid, int step, enum target_signal signal) | |
726 | { | |
727 | int pid = PIDGET (ptid); | |
728 | ||
729 | int request = PTRACE_CONT; | |
730 | ||
731 | if (pid == -1) | |
732 | /* Resume all threads. */ | |
733 | /* I think this only gets used in the non-threaded case, where "resume | |
734 | all threads" and "resume inferior_ptid" are the same. */ | |
735 | pid = PIDGET (inferior_ptid); | |
736 | ||
737 | if (step) | |
738 | { | |
739 | CORE_ADDR pc = read_pc_pid (pid_to_ptid (pid)); | |
740 | gdb_byte buf[LINUX_SYSCALL_LEN]; | |
741 | ||
742 | request = PTRACE_SINGLESTEP; | |
743 | ||
744 | /* Returning from a signal trampoline is done by calling a | |
745 | special system call (sigreturn or rt_sigreturn, see | |
746 | i386-linux-tdep.c for more information). This system call | |
747 | restores the registers that were saved when the signal was | |
748 | raised, including %eflags. That means that single-stepping | |
749 | won't work. Instead, we'll have to modify the signal context | |
750 | that's about to be restored, and set the trace flag there. */ | |
751 | ||
752 | /* First check if PC is at a system call. */ | |
753 | if (read_memory_nobpt (pc, buf, LINUX_SYSCALL_LEN) == 0 | |
754 | && memcmp (buf, linux_syscall, LINUX_SYSCALL_LEN) == 0) | |
755 | { | |
756 | int syscall = read_register_pid (LINUX_SYSCALL_REGNUM, | |
757 | pid_to_ptid (pid)); | |
758 | ||
759 | /* Then check the system call number. */ | |
760 | if (syscall == SYS_sigreturn || syscall == SYS_rt_sigreturn) | |
761 | { | |
762 | CORE_ADDR sp = read_register (I386_ESP_REGNUM); | |
763 | CORE_ADDR addr = sp; | |
764 | unsigned long int eflags; | |
765 | ||
766 | if (syscall == SYS_rt_sigreturn) | |
767 | addr = read_memory_integer (sp + 8, 4) + 20; | |
768 | ||
769 | /* Set the trace flag in the context that's about to be | |
770 | restored. */ | |
771 | addr += LINUX_SIGCONTEXT_EFLAGS_OFFSET; | |
772 | read_memory (addr, (gdb_byte *) &eflags, 4); | |
773 | eflags |= 0x0100; | |
774 | write_memory (addr, (gdb_byte *) &eflags, 4); | |
775 | } | |
776 | } | |
777 | } | |
778 | ||
779 | if (ptrace (request, pid, 0, target_signal_to_host (signal)) == -1) | |
780 | perror_with_name (("ptrace")); | |
781 | } | |
782 | ||
783 | static void (*super_post_startup_inferior) (ptid_t ptid); | |
784 | ||
785 | static void | |
786 | i386_linux_child_post_startup_inferior (ptid_t ptid) | |
787 | { | |
788 | i386_cleanup_dregs (); | |
789 | super_post_startup_inferior (ptid); | |
790 | } | |
791 | ||
792 | void | |
793 | _initialize_i386_linux_nat (void) | |
794 | { | |
795 | struct target_ops *t; | |
796 | ||
797 | /* Fill in the generic GNU/Linux methods. */ | |
798 | t = linux_target (); | |
799 | ||
800 | /* Override the default ptrace resume method. */ | |
801 | t->to_resume = i386_linux_resume; | |
802 | ||
803 | /* Override the GNU/Linux inferior startup hook. */ | |
804 | super_post_startup_inferior = t->to_post_startup_inferior; | |
805 | t->to_post_startup_inferior = i386_linux_child_post_startup_inferior; | |
806 | ||
807 | /* Add our register access methods. */ | |
808 | t->to_fetch_registers = i386_linux_fetch_inferior_registers; | |
809 | t->to_store_registers = i386_linux_store_inferior_registers; | |
810 | ||
811 | /* Register the target. */ | |
812 | linux_nat_add_target (t); | |
813 | } |