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1 | /* Native-dependent code for Linux/x86. | |
2 | Copyright 1999, 2000, 2001 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GDB. | |
5 | ||
6 | This program is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | This program is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program; if not, write to the Free Software | |
18 | Foundation, Inc., 59 Temple Place - Suite 330, | |
19 | Boston, MA 02111-1307, USA. */ | |
20 | ||
21 | #include "defs.h" | |
22 | #include "inferior.h" | |
23 | #include "gdbcore.h" | |
24 | #include "regcache.h" | |
25 | ||
26 | #include "gdb_assert.h" | |
27 | #include <sys/ptrace.h> | |
28 | #include <sys/user.h> | |
29 | #include <sys/procfs.h> | |
30 | ||
31 | #ifdef HAVE_SYS_REG_H | |
32 | #include <sys/reg.h> | |
33 | #endif | |
34 | ||
35 | #ifdef HAVE_SYS_DEBUGREG_H | |
36 | #include <sys/debugreg.h> | |
37 | #endif | |
38 | ||
39 | #ifndef DR_FIRSTADDR | |
40 | #define DR_FIRSTADDR 0 | |
41 | #endif | |
42 | ||
43 | #ifndef DR_LASTADDR | |
44 | #define DR_LASTADDR 3 | |
45 | #endif | |
46 | ||
47 | #ifndef DR_STATUS | |
48 | #define DR_STATUS 6 | |
49 | #endif | |
50 | ||
51 | #ifndef DR_CONTROL | |
52 | #define DR_CONTROL 7 | |
53 | #endif | |
54 | ||
55 | /* Prototypes for supply_gregset etc. */ | |
56 | #include "gregset.h" | |
57 | ||
58 | /* Prototypes for i387_supply_fsave etc. */ | |
59 | #include "i387-nat.h" | |
60 | ||
61 | /* Prototypes for local functions. */ | |
62 | static void dummy_sse_values (void); | |
63 | ||
64 | \f | |
65 | ||
66 | /* The register sets used in Linux ELF core-dumps are identical to the | |
67 | register sets in `struct user' that is used for a.out core-dumps, | |
68 | and is also used by `ptrace'. The corresponding types are | |
69 | `elf_gregset_t' for the general-purpose registers (with | |
70 | `elf_greg_t' the type of a single GP register) and `elf_fpregset_t' | |
71 | for the floating-point registers. | |
72 | ||
73 | Those types used to be available under the names `gregset_t' and | |
74 | `fpregset_t' too, and this file used those names in the past. But | |
75 | those names are now used for the register sets used in the | |
76 | `mcontext_t' type, and have a different size and layout. */ | |
77 | ||
78 | /* Mapping between the general-purpose registers in `struct user' | |
79 | format and GDB's register array layout. */ | |
80 | static int regmap[] = | |
81 | { | |
82 | EAX, ECX, EDX, EBX, | |
83 | UESP, EBP, ESI, EDI, | |
84 | EIP, EFL, CS, SS, | |
85 | DS, ES, FS, GS | |
86 | }; | |
87 | ||
88 | /* Which ptrace request retrieves which registers? | |
89 | These apply to the corresponding SET requests as well. */ | |
90 | #define GETREGS_SUPPLIES(regno) \ | |
91 | (0 <= (regno) && (regno) <= 15) | |
92 | #define GETFPREGS_SUPPLIES(regno) \ | |
93 | (FP0_REGNUM <= (regno) && (regno) <= LAST_FPU_CTRL_REGNUM) | |
94 | #define GETFPXREGS_SUPPLIES(regno) \ | |
95 | (FP0_REGNUM <= (regno) && (regno) <= MXCSR_REGNUM) | |
96 | ||
97 | /* Does the current host support the GETREGS request? */ | |
98 | int have_ptrace_getregs = | |
99 | #ifdef HAVE_PTRACE_GETREGS | |
100 | 1 | |
101 | #else | |
102 | 0 | |
103 | #endif | |
104 | ; | |
105 | ||
106 | /* Does the current host support the GETFPXREGS request? The header | |
107 | file may or may not define it, and even if it is defined, the | |
108 | kernel will return EIO if it's running on a pre-SSE processor. | |
109 | ||
110 | My instinct is to attach this to some architecture- or | |
111 | target-specific data structure, but really, a particular GDB | |
112 | process can only run on top of one kernel at a time. So it's okay | |
113 | for this to be a simple variable. */ | |
114 | int have_ptrace_getfpxregs = | |
115 | #ifdef HAVE_PTRACE_GETFPXREGS | |
116 | 1 | |
117 | #else | |
118 | 0 | |
119 | #endif | |
120 | ; | |
121 | \f | |
122 | ||
123 | /* Support for the user struct. */ | |
124 | ||
125 | /* Return the address of register REGNUM. BLOCKEND is the value of | |
126 | u.u_ar0, which should point to the registers. */ | |
127 | ||
128 | CORE_ADDR | |
129 | register_u_addr (CORE_ADDR blockend, int regnum) | |
130 | { | |
131 | return (blockend + 4 * regmap[regnum]); | |
132 | } | |
133 | ||
134 | /* Return the size of the user struct. */ | |
135 | ||
136 | int | |
137 | kernel_u_size (void) | |
138 | { | |
139 | return (sizeof (struct user)); | |
140 | } | |
141 | \f | |
142 | ||
143 | /* Fetching registers directly from the U area, one at a time. */ | |
144 | ||
145 | /* FIXME: kettenis/2000-03-05: This duplicates code from `inptrace.c'. | |
146 | The problem is that we define FETCH_INFERIOR_REGISTERS since we | |
147 | want to use our own versions of {fetch,store}_inferior_registers | |
148 | that use the GETREGS request. This means that the code in | |
149 | `infptrace.c' is #ifdef'd out. But we need to fall back on that | |
150 | code when GDB is running on top of a kernel that doesn't support | |
151 | the GETREGS request. I want to avoid changing `infptrace.c' right | |
152 | now. */ | |
153 | ||
154 | #ifndef PT_READ_U | |
155 | #define PT_READ_U PTRACE_PEEKUSR | |
156 | #endif | |
157 | #ifndef PT_WRITE_U | |
158 | #define PT_WRITE_U PTRACE_POKEUSR | |
159 | #endif | |
160 | ||
161 | /* Default the type of the ptrace transfer to int. */ | |
162 | #ifndef PTRACE_XFER_TYPE | |
163 | #define PTRACE_XFER_TYPE int | |
164 | #endif | |
165 | ||
166 | /* Registers we shouldn't try to fetch. */ | |
167 | #define OLD_CANNOT_FETCH_REGISTER(regno) ((regno) >= NUM_GREGS) | |
168 | ||
169 | /* Fetch one register. */ | |
170 | ||
171 | static void | |
172 | fetch_register (int regno) | |
173 | { | |
174 | /* This isn't really an address. But ptrace thinks of it as one. */ | |
175 | CORE_ADDR regaddr; | |
176 | char mess[128]; /* For messages */ | |
177 | register int i; | |
178 | unsigned int offset; /* Offset of registers within the u area. */ | |
179 | char buf[MAX_REGISTER_RAW_SIZE]; | |
180 | int tid; | |
181 | ||
182 | if (OLD_CANNOT_FETCH_REGISTER (regno)) | |
183 | { | |
184 | memset (buf, '\0', REGISTER_RAW_SIZE (regno)); /* Supply zeroes */ | |
185 | supply_register (regno, buf); | |
186 | return; | |
187 | } | |
188 | ||
189 | /* Overload thread id onto process id */ | |
190 | if ((tid = TIDGET (inferior_ptid)) == 0) | |
191 | tid = PIDGET (inferior_ptid); /* no thread id, just use process id */ | |
192 | ||
193 | offset = U_REGS_OFFSET; | |
194 | ||
195 | regaddr = register_addr (regno, offset); | |
196 | for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE)) | |
197 | { | |
198 | errno = 0; | |
199 | *(PTRACE_XFER_TYPE *) & buf[i] = ptrace (PT_READ_U, tid, | |
200 | (PTRACE_ARG3_TYPE) regaddr, 0); | |
201 | regaddr += sizeof (PTRACE_XFER_TYPE); | |
202 | if (errno != 0) | |
203 | { | |
204 | sprintf (mess, "reading register %s (#%d)", | |
205 | REGISTER_NAME (regno), regno); | |
206 | perror_with_name (mess); | |
207 | } | |
208 | } | |
209 | supply_register (regno, buf); | |
210 | } | |
211 | ||
212 | /* Fetch register values from the inferior. | |
213 | If REGNO is negative, do this for all registers. | |
214 | Otherwise, REGNO specifies which register (so we can save time). */ | |
215 | ||
216 | void | |
217 | old_fetch_inferior_registers (int regno) | |
218 | { | |
219 | if (regno >= 0) | |
220 | { | |
221 | fetch_register (regno); | |
222 | } | |
223 | else | |
224 | { | |
225 | for (regno = 0; regno < NUM_REGS; regno++) | |
226 | { | |
227 | fetch_register (regno); | |
228 | } | |
229 | } | |
230 | } | |
231 | ||
232 | /* Registers we shouldn't try to store. */ | |
233 | #define OLD_CANNOT_STORE_REGISTER(regno) ((regno) >= NUM_GREGS) | |
234 | ||
235 | /* Store one register. */ | |
236 | ||
237 | static void | |
238 | store_register (int regno) | |
239 | { | |
240 | /* This isn't really an address. But ptrace thinks of it as one. */ | |
241 | CORE_ADDR regaddr; | |
242 | char mess[128]; /* For messages */ | |
243 | register int i; | |
244 | unsigned int offset; /* Offset of registers within the u area. */ | |
245 | int tid; | |
246 | ||
247 | if (OLD_CANNOT_STORE_REGISTER (regno)) | |
248 | { | |
249 | return; | |
250 | } | |
251 | ||
252 | /* Overload thread id onto process id */ | |
253 | if ((tid = TIDGET (inferior_ptid)) == 0) | |
254 | tid = PIDGET (inferior_ptid); /* no thread id, just use process id */ | |
255 | ||
256 | offset = U_REGS_OFFSET; | |
257 | ||
258 | regaddr = register_addr (regno, offset); | |
259 | for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE)) | |
260 | { | |
261 | errno = 0; | |
262 | ptrace (PT_WRITE_U, tid, (PTRACE_ARG3_TYPE) regaddr, | |
263 | *(PTRACE_XFER_TYPE *) & registers[REGISTER_BYTE (regno) + i]); | |
264 | regaddr += sizeof (PTRACE_XFER_TYPE); | |
265 | if (errno != 0) | |
266 | { | |
267 | sprintf (mess, "writing register %s (#%d)", | |
268 | REGISTER_NAME (regno), regno); | |
269 | perror_with_name (mess); | |
270 | } | |
271 | } | |
272 | } | |
273 | ||
274 | /* Store our register values back into the inferior. | |
275 | If REGNO is negative, do this for all registers. | |
276 | Otherwise, REGNO specifies which register (so we can save time). */ | |
277 | ||
278 | void | |
279 | old_store_inferior_registers (int regno) | |
280 | { | |
281 | if (regno >= 0) | |
282 | { | |
283 | store_register (regno); | |
284 | } | |
285 | else | |
286 | { | |
287 | for (regno = 0; regno < NUM_REGS; regno++) | |
288 | { | |
289 | store_register (regno); | |
290 | } | |
291 | } | |
292 | } | |
293 | \f | |
294 | ||
295 | /* Transfering the general-purpose registers between GDB, inferiors | |
296 | and core files. */ | |
297 | ||
298 | /* Fill GDB's register array with the general-purpose register values | |
299 | in *GREGSETP. */ | |
300 | ||
301 | void | |
302 | supply_gregset (elf_gregset_t *gregsetp) | |
303 | { | |
304 | elf_greg_t *regp = (elf_greg_t *) gregsetp; | |
305 | int i; | |
306 | ||
307 | for (i = 0; i < NUM_GREGS; i++) | |
308 | supply_register (i, (char *) (regp + regmap[i])); | |
309 | } | |
310 | ||
311 | /* Fill register REGNO (if it is a general-purpose register) in | |
312 | *GREGSETPS with the value in GDB's register array. If REGNO is -1, | |
313 | do this for all registers. */ | |
314 | ||
315 | void | |
316 | fill_gregset (elf_gregset_t *gregsetp, int regno) | |
317 | { | |
318 | elf_greg_t *regp = (elf_greg_t *) gregsetp; | |
319 | int i; | |
320 | ||
321 | for (i = 0; i < NUM_GREGS; i++) | |
322 | if ((regno == -1 || regno == i)) | |
323 | *(regp + regmap[i]) = *(elf_greg_t *) ®isters[REGISTER_BYTE (i)]; | |
324 | } | |
325 | ||
326 | #ifdef HAVE_PTRACE_GETREGS | |
327 | ||
328 | /* Fetch all general-purpose registers from process/thread TID and | |
329 | store their values in GDB's register array. */ | |
330 | ||
331 | static void | |
332 | fetch_regs (int tid) | |
333 | { | |
334 | elf_gregset_t regs; | |
335 | ||
336 | if (ptrace (PTRACE_GETREGS, tid, 0, (int) ®s) < 0) | |
337 | { | |
338 | if (errno == EIO) | |
339 | { | |
340 | /* The kernel we're running on doesn't support the GETREGS | |
341 | request. Reset `have_ptrace_getregs'. */ | |
342 | have_ptrace_getregs = 0; | |
343 | return; | |
344 | } | |
345 | ||
346 | perror_with_name ("Couldn't get registers"); | |
347 | } | |
348 | ||
349 | supply_gregset (®s); | |
350 | } | |
351 | ||
352 | /* Store all valid general-purpose registers in GDB's register array | |
353 | into the process/thread specified by TID. */ | |
354 | ||
355 | static void | |
356 | store_regs (int tid, int regno) | |
357 | { | |
358 | elf_gregset_t regs; | |
359 | ||
360 | if (ptrace (PTRACE_GETREGS, tid, 0, (int) ®s) < 0) | |
361 | perror_with_name ("Couldn't get registers"); | |
362 | ||
363 | fill_gregset (®s, regno); | |
364 | ||
365 | if (ptrace (PTRACE_SETREGS, tid, 0, (int) ®s) < 0) | |
366 | perror_with_name ("Couldn't write registers"); | |
367 | } | |
368 | ||
369 | #else | |
370 | ||
371 | static void fetch_regs (int tid) {} | |
372 | static void store_regs (int tid, int regno) {} | |
373 | ||
374 | #endif | |
375 | \f | |
376 | ||
377 | /* Transfering floating-point registers between GDB, inferiors and cores. */ | |
378 | ||
379 | /* Fill GDB's register array with the floating-point register values in | |
380 | *FPREGSETP. */ | |
381 | ||
382 | void | |
383 | supply_fpregset (elf_fpregset_t *fpregsetp) | |
384 | { | |
385 | i387_supply_fsave ((char *) fpregsetp); | |
386 | dummy_sse_values (); | |
387 | } | |
388 | ||
389 | /* Fill register REGNO (if it is a floating-point register) in | |
390 | *FPREGSETP with the value in GDB's register array. If REGNO is -1, | |
391 | do this for all registers. */ | |
392 | ||
393 | void | |
394 | fill_fpregset (elf_fpregset_t *fpregsetp, int regno) | |
395 | { | |
396 | i387_fill_fsave ((char *) fpregsetp, regno); | |
397 | } | |
398 | ||
399 | #ifdef HAVE_PTRACE_GETREGS | |
400 | ||
401 | /* Fetch all floating-point registers from process/thread TID and store | |
402 | thier values in GDB's register array. */ | |
403 | ||
404 | static void | |
405 | fetch_fpregs (int tid) | |
406 | { | |
407 | elf_fpregset_t fpregs; | |
408 | ||
409 | if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0) | |
410 | perror_with_name ("Couldn't get floating point status"); | |
411 | ||
412 | supply_fpregset (&fpregs); | |
413 | } | |
414 | ||
415 | /* Store all valid floating-point registers in GDB's register array | |
416 | into the process/thread specified by TID. */ | |
417 | ||
418 | static void | |
419 | store_fpregs (int tid, int regno) | |
420 | { | |
421 | elf_fpregset_t fpregs; | |
422 | ||
423 | if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0) | |
424 | perror_with_name ("Couldn't get floating point status"); | |
425 | ||
426 | fill_fpregset (&fpregs, regno); | |
427 | ||
428 | if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0) | |
429 | perror_with_name ("Couldn't write floating point status"); | |
430 | } | |
431 | ||
432 | #else | |
433 | ||
434 | static void fetch_fpregs (int tid) {} | |
435 | static void store_fpregs (int tid, int regno) {} | |
436 | ||
437 | #endif | |
438 | \f | |
439 | ||
440 | /* Transfering floating-point and SSE registers to and from GDB. */ | |
441 | ||
442 | #ifdef HAVE_PTRACE_GETFPXREGS | |
443 | ||
444 | /* Fill GDB's register array with the floating-point and SSE register | |
445 | values in *FPXREGSETP. */ | |
446 | ||
447 | static void | |
448 | supply_fpxregset (elf_fpxregset_t *fpxregsetp) | |
449 | { | |
450 | i387_supply_fxsave ((char *) fpxregsetp); | |
451 | } | |
452 | ||
453 | /* Fill register REGNO (if it is a floating-point or SSE register) in | |
454 | *FPXREGSETP with the value in GDB's register array. If REGNO is | |
455 | -1, do this for all registers. */ | |
456 | ||
457 | static void | |
458 | fill_fpxregset (elf_fpxregset_t *fpxregsetp, int regno) | |
459 | { | |
460 | i387_fill_fxsave ((char *) fpxregsetp, regno); | |
461 | } | |
462 | ||
463 | /* Fetch all registers covered by the PTRACE_GETFPXREGS request from | |
464 | process/thread TID and store their values in GDB's register array. | |
465 | Return non-zero if successful, zero otherwise. */ | |
466 | ||
467 | static int | |
468 | fetch_fpxregs (int tid) | |
469 | { | |
470 | elf_fpxregset_t fpxregs; | |
471 | ||
472 | if (! have_ptrace_getfpxregs) | |
473 | return 0; | |
474 | ||
475 | if (ptrace (PTRACE_GETFPXREGS, tid, 0, (int) &fpxregs) < 0) | |
476 | { | |
477 | if (errno == EIO) | |
478 | { | |
479 | have_ptrace_getfpxregs = 0; | |
480 | return 0; | |
481 | } | |
482 | ||
483 | perror_with_name ("Couldn't read floating-point and SSE registers"); | |
484 | } | |
485 | ||
486 | supply_fpxregset (&fpxregs); | |
487 | return 1; | |
488 | } | |
489 | ||
490 | /* Store all valid registers in GDB's register array covered by the | |
491 | PTRACE_SETFPXREGS request into the process/thread specified by TID. | |
492 | Return non-zero if successful, zero otherwise. */ | |
493 | ||
494 | static int | |
495 | store_fpxregs (int tid, int regno) | |
496 | { | |
497 | elf_fpxregset_t fpxregs; | |
498 | ||
499 | if (! have_ptrace_getfpxregs) | |
500 | return 0; | |
501 | ||
502 | if (ptrace (PTRACE_GETFPXREGS, tid, 0, &fpxregs) == -1) | |
503 | { | |
504 | if (errno == EIO) | |
505 | { | |
506 | have_ptrace_getfpxregs = 0; | |
507 | return 0; | |
508 | } | |
509 | ||
510 | perror_with_name ("Couldn't read floating-point and SSE registers"); | |
511 | } | |
512 | ||
513 | fill_fpxregset (&fpxregs, regno); | |
514 | ||
515 | if (ptrace (PTRACE_SETFPXREGS, tid, 0, &fpxregs) == -1) | |
516 | perror_with_name ("Couldn't write floating-point and SSE registers"); | |
517 | ||
518 | return 1; | |
519 | } | |
520 | ||
521 | /* Fill the XMM registers in the register array with dummy values. For | |
522 | cases where we don't have access to the XMM registers. I think | |
523 | this is cleaner than printing a warning. For a cleaner solution, | |
524 | we should gdbarchify the i386 family. */ | |
525 | ||
526 | static void | |
527 | dummy_sse_values (void) | |
528 | { | |
529 | /* C doesn't have a syntax for NaN's, so write it out as an array of | |
530 | longs. */ | |
531 | static long dummy[4] = { 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff }; | |
532 | static long mxcsr = 0x1f80; | |
533 | int reg; | |
534 | ||
535 | for (reg = 0; reg < 8; reg++) | |
536 | supply_register (XMM0_REGNUM + reg, (char *) dummy); | |
537 | supply_register (MXCSR_REGNUM, (char *) &mxcsr); | |
538 | } | |
539 | ||
540 | #else | |
541 | ||
542 | static int fetch_fpxregs (int tid) { return 0; } | |
543 | static int store_fpxregs (int tid, int regno) { return 0; } | |
544 | static void dummy_sse_values (void) {} | |
545 | ||
546 | #endif /* HAVE_PTRACE_GETFPXREGS */ | |
547 | \f | |
548 | ||
549 | /* Transferring arbitrary registers between GDB and inferior. */ | |
550 | ||
551 | /* Check if register REGNO in the child process is accessible. | |
552 | If we are accessing registers directly via the U area, only the | |
553 | general-purpose registers are available. | |
554 | All registers should be accessible if we have GETREGS support. */ | |
555 | ||
556 | int | |
557 | cannot_fetch_register (int regno) | |
558 | { | |
559 | if (! have_ptrace_getregs) | |
560 | return OLD_CANNOT_FETCH_REGISTER (regno); | |
561 | return 0; | |
562 | } | |
563 | int | |
564 | cannot_store_register (int regno) | |
565 | { | |
566 | if (! have_ptrace_getregs) | |
567 | return OLD_CANNOT_STORE_REGISTER (regno); | |
568 | return 0; | |
569 | } | |
570 | ||
571 | /* Fetch register REGNO from the child process. If REGNO is -1, do | |
572 | this for all registers (including the floating point and SSE | |
573 | registers). */ | |
574 | ||
575 | void | |
576 | fetch_inferior_registers (int regno) | |
577 | { | |
578 | int tid; | |
579 | ||
580 | /* Use the old method of peeking around in `struct user' if the | |
581 | GETREGS request isn't available. */ | |
582 | if (! have_ptrace_getregs) | |
583 | { | |
584 | old_fetch_inferior_registers (regno); | |
585 | return; | |
586 | } | |
587 | ||
588 | /* Linux LWP ID's are process ID's. */ | |
589 | if ((tid = TIDGET (inferior_ptid)) == 0) | |
590 | tid = PIDGET (inferior_ptid); /* Not a threaded program. */ | |
591 | ||
592 | /* Use the PTRACE_GETFPXREGS request whenever possible, since it | |
593 | transfers more registers in one system call, and we'll cache the | |
594 | results. But remember that fetch_fpxregs can fail, and return | |
595 | zero. */ | |
596 | if (regno == -1) | |
597 | { | |
598 | fetch_regs (tid); | |
599 | ||
600 | /* The call above might reset `have_ptrace_getregs'. */ | |
601 | if (! have_ptrace_getregs) | |
602 | { | |
603 | old_fetch_inferior_registers (-1); | |
604 | return; | |
605 | } | |
606 | ||
607 | if (fetch_fpxregs (tid)) | |
608 | return; | |
609 | fetch_fpregs (tid); | |
610 | return; | |
611 | } | |
612 | ||
613 | if (GETREGS_SUPPLIES (regno)) | |
614 | { | |
615 | fetch_regs (tid); | |
616 | return; | |
617 | } | |
618 | ||
619 | if (GETFPXREGS_SUPPLIES (regno)) | |
620 | { | |
621 | if (fetch_fpxregs (tid)) | |
622 | return; | |
623 | ||
624 | /* Either our processor or our kernel doesn't support the SSE | |
625 | registers, so read the FP registers in the traditional way, | |
626 | and fill the SSE registers with dummy values. It would be | |
627 | more graceful to handle differences in the register set using | |
628 | gdbarch. Until then, this will at least make things work | |
629 | plausibly. */ | |
630 | fetch_fpregs (tid); | |
631 | return; | |
632 | } | |
633 | ||
634 | internal_error (__FILE__, __LINE__, | |
635 | "Got request for bad register number %d.", regno); | |
636 | } | |
637 | ||
638 | /* Store register REGNO back into the child process. If REGNO is -1, | |
639 | do this for all registers (including the floating point and SSE | |
640 | registers). */ | |
641 | void | |
642 | store_inferior_registers (int regno) | |
643 | { | |
644 | int tid; | |
645 | ||
646 | /* Use the old method of poking around in `struct user' if the | |
647 | SETREGS request isn't available. */ | |
648 | if (! have_ptrace_getregs) | |
649 | { | |
650 | old_store_inferior_registers (regno); | |
651 | return; | |
652 | } | |
653 | ||
654 | /* Linux LWP ID's are process ID's. */ | |
655 | if ((tid = TIDGET (inferior_ptid)) == 0) | |
656 | tid = PIDGET (inferior_ptid); /* Not a threaded program. */ | |
657 | ||
658 | /* Use the PTRACE_SETFPXREGS requests whenever possible, since it | |
659 | transfers more registers in one system call. But remember that | |
660 | store_fpxregs can fail, and return zero. */ | |
661 | if (regno == -1) | |
662 | { | |
663 | store_regs (tid, regno); | |
664 | if (store_fpxregs (tid, regno)) | |
665 | return; | |
666 | store_fpregs (tid, regno); | |
667 | return; | |
668 | } | |
669 | ||
670 | if (GETREGS_SUPPLIES (regno)) | |
671 | { | |
672 | store_regs (tid, regno); | |
673 | return; | |
674 | } | |
675 | ||
676 | if (GETFPXREGS_SUPPLIES (regno)) | |
677 | { | |
678 | if (store_fpxregs (tid, regno)) | |
679 | return; | |
680 | ||
681 | /* Either our processor or our kernel doesn't support the SSE | |
682 | registers, so just write the FP registers in the traditional | |
683 | way. */ | |
684 | store_fpregs (tid, regno); | |
685 | return; | |
686 | } | |
687 | ||
688 | internal_error (__FILE__, __LINE__, | |
689 | "Got request to store bad register number %d.", regno); | |
690 | } | |
691 | \f | |
692 | ||
693 | static unsigned long | |
694 | i386_linux_dr_get (int regnum) | |
695 | { | |
696 | int tid; | |
697 | unsigned long value; | |
698 | ||
699 | /* FIXME: kettenis/2001-01-29: It's not clear what we should do with | |
700 | multi-threaded processes here. For now, pretend there is just | |
701 | one thread. */ | |
702 | tid = PIDGET (inferior_ptid); | |
703 | ||
704 | /* FIXME: kettenis/2001-03-27: Calling perror_with_name if the | |
705 | ptrace call fails breaks debugging remote targets. The correct | |
706 | way to fix this is to add the hardware breakpoint and watchpoint | |
707 | stuff to the target vectore. For now, just return zero if the | |
708 | ptrace call fails. */ | |
709 | errno = 0; | |
710 | value = ptrace (PT_READ_U, tid, | |
711 | offsetof (struct user, u_debugreg[regnum]), 0); | |
712 | if (errno != 0) | |
713 | #if 0 | |
714 | perror_with_name ("Couldn't read debug register"); | |
715 | #else | |
716 | return 0; | |
717 | #endif | |
718 | ||
719 | return value; | |
720 | } | |
721 | ||
722 | static void | |
723 | i386_linux_dr_set (int regnum, unsigned long value) | |
724 | { | |
725 | int tid; | |
726 | ||
727 | /* FIXME: kettenis/2001-01-29: It's not clear what we should do with | |
728 | multi-threaded processes here. For now, pretend there is just | |
729 | one thread. */ | |
730 | tid = PIDGET (inferior_ptid); | |
731 | ||
732 | errno = 0; | |
733 | ptrace (PT_WRITE_U, tid, | |
734 | offsetof (struct user, u_debugreg[regnum]), value); | |
735 | if (errno != 0) | |
736 | perror_with_name ("Couldn't write debug register"); | |
737 | } | |
738 | ||
739 | void | |
740 | i386_linux_dr_set_control (unsigned long control) | |
741 | { | |
742 | i386_linux_dr_set (DR_CONTROL, control); | |
743 | } | |
744 | ||
745 | void | |
746 | i386_linux_dr_set_addr (int regnum, CORE_ADDR addr) | |
747 | { | |
748 | gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR); | |
749 | ||
750 | i386_linux_dr_set (DR_FIRSTADDR + regnum, addr); | |
751 | } | |
752 | ||
753 | void | |
754 | i386_linux_dr_reset_addr (int regnum) | |
755 | { | |
756 | gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR); | |
757 | ||
758 | i386_linux_dr_set (DR_FIRSTADDR + regnum, 0L); | |
759 | } | |
760 | ||
761 | unsigned long | |
762 | i386_linux_dr_get_status (void) | |
763 | { | |
764 | return i386_linux_dr_get (DR_STATUS); | |
765 | } | |
766 | \f | |
767 | ||
768 | /* Interpreting register set info found in core files. */ | |
769 | ||
770 | /* Provide registers to GDB from a core file. | |
771 | ||
772 | (We can't use the generic version of this function in | |
773 | core-regset.c, because Linux has *three* different kinds of | |
774 | register set notes. core-regset.c would have to call | |
775 | supply_fpxregset, which most platforms don't have.) | |
776 | ||
777 | CORE_REG_SECT points to an array of bytes, which are the contents | |
778 | of a `note' from a core file which BFD thinks might contain | |
779 | register contents. CORE_REG_SIZE is its size. | |
780 | ||
781 | WHICH says which register set corelow suspects this is: | |
782 | 0 --- the general-purpose register set, in elf_gregset_t format | |
783 | 2 --- the floating-point register set, in elf_fpregset_t format | |
784 | 3 --- the extended floating-point register set, in elf_fpxregset_t format | |
785 | ||
786 | REG_ADDR isn't used on Linux. */ | |
787 | ||
788 | static void | |
789 | fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, | |
790 | int which, CORE_ADDR reg_addr) | |
791 | { | |
792 | elf_gregset_t gregset; | |
793 | elf_fpregset_t fpregset; | |
794 | ||
795 | switch (which) | |
796 | { | |
797 | case 0: | |
798 | if (core_reg_size != sizeof (gregset)) | |
799 | warning ("Wrong size gregset in core file."); | |
800 | else | |
801 | { | |
802 | memcpy (&gregset, core_reg_sect, sizeof (gregset)); | |
803 | supply_gregset (&gregset); | |
804 | } | |
805 | break; | |
806 | ||
807 | case 2: | |
808 | if (core_reg_size != sizeof (fpregset)) | |
809 | warning ("Wrong size fpregset in core file."); | |
810 | else | |
811 | { | |
812 | memcpy (&fpregset, core_reg_sect, sizeof (fpregset)); | |
813 | supply_fpregset (&fpregset); | |
814 | } | |
815 | break; | |
816 | ||
817 | #ifdef HAVE_PTRACE_GETFPXREGS | |
818 | { | |
819 | elf_fpxregset_t fpxregset; | |
820 | ||
821 | case 3: | |
822 | if (core_reg_size != sizeof (fpxregset)) | |
823 | warning ("Wrong size fpxregset in core file."); | |
824 | else | |
825 | { | |
826 | memcpy (&fpxregset, core_reg_sect, sizeof (fpxregset)); | |
827 | supply_fpxregset (&fpxregset); | |
828 | } | |
829 | break; | |
830 | } | |
831 | #endif | |
832 | ||
833 | default: | |
834 | /* We've covered all the kinds of registers we know about here, | |
835 | so this must be something we wouldn't know what to do with | |
836 | anyway. Just ignore it. */ | |
837 | break; | |
838 | } | |
839 | } | |
840 | \f | |
841 | ||
842 | /* The instruction for a Linux system call is: | |
843 | int $0x80 | |
844 | or 0xcd 0x80. */ | |
845 | ||
846 | static const unsigned char linux_syscall[] = { 0xcd, 0x80 }; | |
847 | ||
848 | #define LINUX_SYSCALL_LEN (sizeof linux_syscall) | |
849 | ||
850 | /* The system call number is stored in the %eax register. */ | |
851 | #define LINUX_SYSCALL_REGNUM 0 /* %eax */ | |
852 | ||
853 | /* We are specifically interested in the sigreturn and rt_sigreturn | |
854 | system calls. */ | |
855 | ||
856 | #ifndef SYS_sigreturn | |
857 | #define SYS_sigreturn 0x77 | |
858 | #endif | |
859 | #ifndef SYS_rt_sigreturn | |
860 | #define SYS_rt_sigreturn 0xad | |
861 | #endif | |
862 | ||
863 | /* Offset to saved processor flags, from <asm/sigcontext.h>. */ | |
864 | #define LINUX_SIGCONTEXT_EFLAGS_OFFSET (64) | |
865 | ||
866 | /* Resume execution of the inferior process. | |
867 | If STEP is nonzero, single-step it. | |
868 | If SIGNAL is nonzero, give it that signal. */ | |
869 | ||
870 | void | |
871 | child_resume (ptid_t ptid, int step, enum target_signal signal) | |
872 | { | |
873 | int pid = PIDGET (ptid); | |
874 | ||
875 | int request = PTRACE_CONT; | |
876 | ||
877 | if (pid == -1) | |
878 | /* Resume all threads. */ | |
879 | /* I think this only gets used in the non-threaded case, where "resume | |
880 | all threads" and "resume inferior_ptid" are the same. */ | |
881 | pid = PIDGET (inferior_ptid); | |
882 | ||
883 | if (step) | |
884 | { | |
885 | CORE_ADDR pc = read_pc_pid (pid_to_ptid (pid)); | |
886 | unsigned char buf[LINUX_SYSCALL_LEN]; | |
887 | ||
888 | request = PTRACE_SINGLESTEP; | |
889 | ||
890 | /* Returning from a signal trampoline is done by calling a | |
891 | special system call (sigreturn or rt_sigreturn, see | |
892 | i386-linux-tdep.c for more information). This system call | |
893 | restores the registers that were saved when the signal was | |
894 | raised, including %eflags. That means that single-stepping | |
895 | won't work. Instead, we'll have to modify the signal context | |
896 | that's about to be restored, and set the trace flag there. */ | |
897 | ||
898 | /* First check if PC is at a system call. */ | |
899 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SYSCALL_LEN) == 0 | |
900 | && memcmp (buf, linux_syscall, LINUX_SYSCALL_LEN) == 0) | |
901 | { | |
902 | int syscall = read_register_pid (LINUX_SYSCALL_REGNUM, | |
903 | pid_to_ptid (pid)); | |
904 | ||
905 | /* Then check the system call number. */ | |
906 | if (syscall == SYS_sigreturn || syscall == SYS_rt_sigreturn) | |
907 | { | |
908 | CORE_ADDR sp = read_register (SP_REGNUM); | |
909 | CORE_ADDR addr = sp; | |
910 | unsigned long int eflags; | |
911 | ||
912 | if (syscall == SYS_rt_sigreturn) | |
913 | addr = read_memory_integer (sp + 8, 4) + 20; | |
914 | ||
915 | /* Set the trace flag in the context that's about to be | |
916 | restored. */ | |
917 | addr += LINUX_SIGCONTEXT_EFLAGS_OFFSET; | |
918 | read_memory (addr, (char *) &eflags, 4); | |
919 | eflags |= 0x0100; | |
920 | write_memory (addr, (char *) &eflags, 4); | |
921 | } | |
922 | } | |
923 | } | |
924 | ||
925 | if (ptrace (request, pid, 0, target_signal_to_host (signal)) == -1) | |
926 | perror_with_name ("ptrace"); | |
927 | } | |
928 | \f | |
929 | ||
930 | /* Register that we are able to handle Linux ELF core file formats. */ | |
931 | ||
932 | static struct core_fns linux_elf_core_fns = | |
933 | { | |
934 | bfd_target_elf_flavour, /* core_flavour */ | |
935 | default_check_format, /* check_format */ | |
936 | default_core_sniffer, /* core_sniffer */ | |
937 | fetch_core_registers, /* core_read_registers */ | |
938 | NULL /* next */ | |
939 | }; | |
940 | ||
941 | void | |
942 | _initialize_i386_linux_nat (void) | |
943 | { | |
944 | add_core_fns (&linux_elf_core_fns); | |
945 | } |