| 1 | /* Memory breakpoint operations for the remote server for GDB. |
| 2 | Copyright (C) 2002, 2003, 2005, 2007, 2008, 2009, 2010 |
| 3 | Free Software Foundation, Inc. |
| 4 | |
| 5 | Contributed by MontaVista Software. |
| 6 | |
| 7 | This file is part of GDB. |
| 8 | |
| 9 | This program is free software; you can redistribute it and/or modify |
| 10 | it under the terms of the GNU General Public License as published by |
| 11 | the Free Software Foundation; either version 3 of the License, or |
| 12 | (at your option) any later version. |
| 13 | |
| 14 | This program is distributed in the hope that it will be useful, |
| 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | GNU General Public License for more details. |
| 18 | |
| 19 | You should have received a copy of the GNU General Public License |
| 20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 21 | |
| 22 | #include "server.h" |
| 23 | |
| 24 | const unsigned char *breakpoint_data; |
| 25 | int breakpoint_len; |
| 26 | |
| 27 | #define MAX_BREAKPOINT_LEN 8 |
| 28 | |
| 29 | /* GDB will never try to install multiple breakpoints at the same |
| 30 | address. But, we need to keep track of internal breakpoints too, |
| 31 | and so we do need to be able to install multiple breakpoints at the |
| 32 | same address transparently. We keep track of two different, and |
| 33 | closely related structures. A raw breakpoint, which manages the |
| 34 | low level, close to the metal aspect of a breakpoint. It holds the |
| 35 | breakpoint address, and a buffer holding a copy of the instructions |
| 36 | that would be in memory had not been a breakpoint there (we call |
| 37 | that the shadow memory of the breakpoint). We occasionally need to |
| 38 | temporarilly uninsert a breakpoint without the client knowing about |
| 39 | it (e.g., to step over an internal breakpoint), so we keep an |
| 40 | `inserted' state associated with this low level breakpoint |
| 41 | structure. There can only be one such object for a given address. |
| 42 | Then, we have (a bit higher level) breakpoints. This structure |
| 43 | holds a callback to be called whenever a breakpoint is hit, a |
| 44 | high-level type, and a link to a low level raw breakpoint. There |
| 45 | can be many high-level breakpoints at the same address, and all of |
| 46 | them will point to the same raw breakpoint, which is reference |
| 47 | counted. */ |
| 48 | |
| 49 | /* The low level, physical, raw breakpoint. */ |
| 50 | struct raw_breakpoint |
| 51 | { |
| 52 | struct raw_breakpoint *next; |
| 53 | |
| 54 | /* A reference count. Each high level breakpoint referencing this |
| 55 | raw breakpoint accounts for one reference. */ |
| 56 | int refcount; |
| 57 | |
| 58 | /* The breakpoint's insertion address. There can only be one raw |
| 59 | breakpoint for a given PC. */ |
| 60 | CORE_ADDR pc; |
| 61 | |
| 62 | /* The breakpoint's shadow memory. */ |
| 63 | unsigned char old_data[MAX_BREAKPOINT_LEN]; |
| 64 | |
| 65 | /* Non-zero if this breakpoint is currently inserted in the |
| 66 | inferior. */ |
| 67 | int inserted; |
| 68 | }; |
| 69 | |
| 70 | /* The type of a breakpoint. */ |
| 71 | enum bkpt_type |
| 72 | { |
| 73 | /* A GDB breakpoint, requested with a Z0 packet. */ |
| 74 | gdb_breakpoint, |
| 75 | |
| 76 | /* A basic-software-single-step breakpoint. */ |
| 77 | reinsert_breakpoint, |
| 78 | |
| 79 | /* Any other breakpoint type that doesn't require specific |
| 80 | treatment goes here. E.g., an event breakpoint. */ |
| 81 | other_breakpoint, |
| 82 | }; |
| 83 | |
| 84 | /* A high level (in gdbserver's perspective) breakpoint. */ |
| 85 | struct breakpoint |
| 86 | { |
| 87 | struct breakpoint *next; |
| 88 | |
| 89 | /* The breakpoint's type. */ |
| 90 | enum bkpt_type type; |
| 91 | |
| 92 | /* Link to this breakpoint's raw breakpoint. This is always |
| 93 | non-NULL. */ |
| 94 | struct raw_breakpoint *raw; |
| 95 | |
| 96 | /* Function to call when we hit this breakpoint. If it returns 1, |
| 97 | the breakpoint shall be deleted; 0 or if this callback is NULL, |
| 98 | it will be left inserted. */ |
| 99 | int (*handler) (CORE_ADDR); |
| 100 | }; |
| 101 | |
| 102 | static struct raw_breakpoint * |
| 103 | find_raw_breakpoint_at (CORE_ADDR where) |
| 104 | { |
| 105 | struct process_info *proc = current_process (); |
| 106 | struct raw_breakpoint *bp; |
| 107 | |
| 108 | for (bp = proc->raw_breakpoints; bp != NULL; bp = bp->next) |
| 109 | if (bp->pc == where) |
| 110 | return bp; |
| 111 | |
| 112 | return NULL; |
| 113 | } |
| 114 | |
| 115 | static struct raw_breakpoint * |
| 116 | set_raw_breakpoint_at (CORE_ADDR where) |
| 117 | { |
| 118 | struct process_info *proc = current_process (); |
| 119 | struct raw_breakpoint *bp; |
| 120 | int err; |
| 121 | |
| 122 | if (breakpoint_data == NULL) |
| 123 | error ("Target does not support breakpoints."); |
| 124 | |
| 125 | bp = find_raw_breakpoint_at (where); |
| 126 | if (bp != NULL) |
| 127 | { |
| 128 | bp->refcount++; |
| 129 | return bp; |
| 130 | } |
| 131 | |
| 132 | bp = xcalloc (1, sizeof (*bp)); |
| 133 | bp->pc = where; |
| 134 | bp->refcount = 1; |
| 135 | |
| 136 | err = (*the_target->read_memory) (where, bp->old_data, |
| 137 | breakpoint_len); |
| 138 | if (err != 0) |
| 139 | { |
| 140 | if (debug_threads) |
| 141 | fprintf (stderr, |
| 142 | "Failed to read shadow memory of" |
| 143 | " breakpoint at 0x%s (%s).\n", |
| 144 | paddress (where), strerror (err)); |
| 145 | free (bp); |
| 146 | return NULL; |
| 147 | } |
| 148 | |
| 149 | err = (*the_target->write_memory) (where, breakpoint_data, |
| 150 | breakpoint_len); |
| 151 | if (err != 0) |
| 152 | { |
| 153 | if (debug_threads) |
| 154 | fprintf (stderr, |
| 155 | "Failed to insert breakpoint at 0x%s (%s).\n", |
| 156 | paddress (where), strerror (err)); |
| 157 | free (bp); |
| 158 | return NULL; |
| 159 | } |
| 160 | |
| 161 | /* Link the breakpoint in. */ |
| 162 | bp->inserted = 1; |
| 163 | bp->next = proc->raw_breakpoints; |
| 164 | proc->raw_breakpoints = bp; |
| 165 | return bp; |
| 166 | } |
| 167 | |
| 168 | struct breakpoint * |
| 169 | set_breakpoint_at (CORE_ADDR where, int (*handler) (CORE_ADDR)) |
| 170 | { |
| 171 | struct process_info *proc = current_process (); |
| 172 | struct breakpoint *bp; |
| 173 | struct raw_breakpoint *raw; |
| 174 | |
| 175 | raw = set_raw_breakpoint_at (where); |
| 176 | |
| 177 | if (raw == NULL) |
| 178 | { |
| 179 | /* warn? */ |
| 180 | return NULL; |
| 181 | } |
| 182 | |
| 183 | bp = xcalloc (1, sizeof (struct breakpoint)); |
| 184 | bp->type = other_breakpoint; |
| 185 | |
| 186 | bp->raw = raw; |
| 187 | bp->handler = handler; |
| 188 | |
| 189 | bp->next = proc->breakpoints; |
| 190 | proc->breakpoints = bp; |
| 191 | |
| 192 | return bp; |
| 193 | } |
| 194 | |
| 195 | static int |
| 196 | delete_raw_breakpoint (struct process_info *proc, struct raw_breakpoint *todel) |
| 197 | { |
| 198 | struct raw_breakpoint *bp, **bp_link; |
| 199 | int ret; |
| 200 | |
| 201 | bp = proc->raw_breakpoints; |
| 202 | bp_link = &proc->raw_breakpoints; |
| 203 | |
| 204 | while (bp) |
| 205 | { |
| 206 | if (bp == todel) |
| 207 | { |
| 208 | if (bp->inserted) |
| 209 | { |
| 210 | struct raw_breakpoint *prev_bp_link = *bp_link; |
| 211 | |
| 212 | *bp_link = bp->next; |
| 213 | |
| 214 | ret = (*the_target->write_memory) (bp->pc, bp->old_data, |
| 215 | breakpoint_len); |
| 216 | if (ret != 0) |
| 217 | { |
| 218 | /* Something went wrong, relink the breakpoint. */ |
| 219 | *bp_link = prev_bp_link; |
| 220 | |
| 221 | if (debug_threads) |
| 222 | fprintf (stderr, |
| 223 | "Failed to uninsert raw breakpoint " |
| 224 | "at 0x%s (%s) while deleting it.\n", |
| 225 | paddress (bp->pc), strerror (ret)); |
| 226 | return ret; |
| 227 | } |
| 228 | |
| 229 | } |
| 230 | else |
| 231 | *bp_link = bp->next; |
| 232 | |
| 233 | free (bp); |
| 234 | return 0; |
| 235 | } |
| 236 | else |
| 237 | { |
| 238 | bp_link = &bp->next; |
| 239 | bp = *bp_link; |
| 240 | } |
| 241 | } |
| 242 | |
| 243 | warning ("Could not find raw breakpoint in list."); |
| 244 | return ENOENT; |
| 245 | } |
| 246 | |
| 247 | static int |
| 248 | release_breakpoint (struct process_info *proc, struct breakpoint *bp) |
| 249 | { |
| 250 | int newrefcount; |
| 251 | int ret; |
| 252 | |
| 253 | newrefcount = bp->raw->refcount - 1; |
| 254 | if (newrefcount == 0) |
| 255 | { |
| 256 | ret = delete_raw_breakpoint (proc, bp->raw); |
| 257 | if (ret != 0) |
| 258 | return ret; |
| 259 | } |
| 260 | else |
| 261 | bp->raw->refcount = newrefcount; |
| 262 | |
| 263 | free (bp); |
| 264 | |
| 265 | return 0; |
| 266 | } |
| 267 | |
| 268 | static int |
| 269 | delete_breakpoint_1 (struct process_info *proc, struct breakpoint *todel) |
| 270 | { |
| 271 | struct breakpoint *bp, **bp_link; |
| 272 | int err; |
| 273 | |
| 274 | bp = proc->breakpoints; |
| 275 | bp_link = &proc->breakpoints; |
| 276 | |
| 277 | while (bp) |
| 278 | { |
| 279 | if (bp == todel) |
| 280 | { |
| 281 | *bp_link = bp->next; |
| 282 | |
| 283 | err = release_breakpoint (proc, bp); |
| 284 | if (err != 0) |
| 285 | return err; |
| 286 | |
| 287 | bp = *bp_link; |
| 288 | return 0; |
| 289 | } |
| 290 | else |
| 291 | { |
| 292 | bp_link = &bp->next; |
| 293 | bp = *bp_link; |
| 294 | } |
| 295 | } |
| 296 | |
| 297 | warning ("Could not find breakpoint in list."); |
| 298 | return ENOENT; |
| 299 | } |
| 300 | |
| 301 | static int |
| 302 | delete_breakpoint (struct breakpoint *todel) |
| 303 | { |
| 304 | struct process_info *proc = current_process (); |
| 305 | return delete_breakpoint_1 (proc, todel); |
| 306 | } |
| 307 | |
| 308 | static struct breakpoint * |
| 309 | find_gdb_breakpoint_at (CORE_ADDR where) |
| 310 | { |
| 311 | struct process_info *proc = current_process (); |
| 312 | struct breakpoint *bp; |
| 313 | |
| 314 | for (bp = proc->breakpoints; bp != NULL; bp = bp->next) |
| 315 | if (bp->type == gdb_breakpoint && bp->raw->pc == where) |
| 316 | return bp; |
| 317 | |
| 318 | return NULL; |
| 319 | } |
| 320 | |
| 321 | int |
| 322 | set_gdb_breakpoint_at (CORE_ADDR where) |
| 323 | { |
| 324 | struct breakpoint *bp; |
| 325 | |
| 326 | if (breakpoint_data == NULL) |
| 327 | return 1; |
| 328 | |
| 329 | bp = set_breakpoint_at (where, NULL); |
| 330 | if (bp == NULL) |
| 331 | return -1; |
| 332 | |
| 333 | bp->type = gdb_breakpoint; |
| 334 | return 0; |
| 335 | } |
| 336 | |
| 337 | int |
| 338 | delete_gdb_breakpoint_at (CORE_ADDR addr) |
| 339 | { |
| 340 | struct breakpoint *bp; |
| 341 | int err; |
| 342 | |
| 343 | if (breakpoint_data == NULL) |
| 344 | return 1; |
| 345 | |
| 346 | bp = find_gdb_breakpoint_at (addr); |
| 347 | if (bp == NULL) |
| 348 | return -1; |
| 349 | |
| 350 | err = delete_breakpoint (bp); |
| 351 | if (err) |
| 352 | return -1; |
| 353 | |
| 354 | return 0; |
| 355 | } |
| 356 | |
| 357 | int |
| 358 | gdb_breakpoint_here (CORE_ADDR where) |
| 359 | { |
| 360 | struct breakpoint *bp = find_gdb_breakpoint_at (where); |
| 361 | |
| 362 | return (bp != NULL); |
| 363 | } |
| 364 | |
| 365 | void |
| 366 | set_reinsert_breakpoint (CORE_ADDR stop_at) |
| 367 | { |
| 368 | struct breakpoint *bp; |
| 369 | |
| 370 | bp = set_breakpoint_at (stop_at, NULL); |
| 371 | bp->type = reinsert_breakpoint; |
| 372 | } |
| 373 | |
| 374 | void |
| 375 | delete_reinsert_breakpoints (void) |
| 376 | { |
| 377 | struct process_info *proc = current_process (); |
| 378 | struct breakpoint *bp, **bp_link; |
| 379 | |
| 380 | bp = proc->breakpoints; |
| 381 | bp_link = &proc->breakpoints; |
| 382 | |
| 383 | while (bp) |
| 384 | { |
| 385 | if (bp->type == reinsert_breakpoint) |
| 386 | { |
| 387 | *bp_link = bp->next; |
| 388 | release_breakpoint (proc, bp); |
| 389 | bp = *bp_link; |
| 390 | } |
| 391 | else |
| 392 | { |
| 393 | bp_link = &bp->next; |
| 394 | bp = *bp_link; |
| 395 | } |
| 396 | } |
| 397 | } |
| 398 | |
| 399 | static void |
| 400 | uninsert_raw_breakpoint (struct raw_breakpoint *bp) |
| 401 | { |
| 402 | if (bp->inserted) |
| 403 | { |
| 404 | int err; |
| 405 | |
| 406 | bp->inserted = 0; |
| 407 | err = (*the_target->write_memory) (bp->pc, bp->old_data, |
| 408 | breakpoint_len); |
| 409 | if (err != 0) |
| 410 | { |
| 411 | bp->inserted = 1; |
| 412 | |
| 413 | if (debug_threads) |
| 414 | fprintf (stderr, |
| 415 | "Failed to uninsert raw breakpoint at 0x%s (%s).\n", |
| 416 | paddress (bp->pc), strerror (err)); |
| 417 | } |
| 418 | } |
| 419 | } |
| 420 | |
| 421 | void |
| 422 | uninsert_breakpoints_at (CORE_ADDR pc) |
| 423 | { |
| 424 | struct raw_breakpoint *bp; |
| 425 | |
| 426 | bp = find_raw_breakpoint_at (pc); |
| 427 | if (bp == NULL) |
| 428 | { |
| 429 | /* This can happen when we remove all breakpoints while handling |
| 430 | a step-over. */ |
| 431 | if (debug_threads) |
| 432 | fprintf (stderr, |
| 433 | "Could not find breakpoint at 0x%s " |
| 434 | "in list (uninserting).\n", |
| 435 | paddress (pc)); |
| 436 | return; |
| 437 | } |
| 438 | |
| 439 | if (bp->inserted) |
| 440 | uninsert_raw_breakpoint (bp); |
| 441 | } |
| 442 | |
| 443 | static void |
| 444 | reinsert_raw_breakpoint (struct raw_breakpoint *bp) |
| 445 | { |
| 446 | int err; |
| 447 | |
| 448 | if (bp->inserted) |
| 449 | error ("Breakpoint already inserted at reinsert time."); |
| 450 | |
| 451 | err = (*the_target->write_memory) (bp->pc, breakpoint_data, |
| 452 | breakpoint_len); |
| 453 | if (err == 0) |
| 454 | bp->inserted = 1; |
| 455 | else if (debug_threads) |
| 456 | fprintf (stderr, |
| 457 | "Failed to reinsert breakpoint at 0x%s (%s).\n", |
| 458 | paddress (bp->pc), strerror (err)); |
| 459 | } |
| 460 | |
| 461 | void |
| 462 | reinsert_breakpoints_at (CORE_ADDR pc) |
| 463 | { |
| 464 | struct raw_breakpoint *bp; |
| 465 | |
| 466 | bp = find_raw_breakpoint_at (pc); |
| 467 | if (bp == NULL) |
| 468 | { |
| 469 | /* This can happen when we remove all breakpoints while handling |
| 470 | a step-over. */ |
| 471 | if (debug_threads) |
| 472 | fprintf (stderr, |
| 473 | "Could not find raw breakpoint at 0x%s " |
| 474 | "in list (reinserting).\n", |
| 475 | paddress (pc)); |
| 476 | return; |
| 477 | } |
| 478 | |
| 479 | reinsert_raw_breakpoint (bp); |
| 480 | } |
| 481 | |
| 482 | void |
| 483 | check_breakpoints (CORE_ADDR stop_pc) |
| 484 | { |
| 485 | struct process_info *proc = current_process (); |
| 486 | struct breakpoint *bp, **bp_link; |
| 487 | |
| 488 | bp = proc->breakpoints; |
| 489 | bp_link = &proc->breakpoints; |
| 490 | |
| 491 | while (bp) |
| 492 | { |
| 493 | if (bp->raw->pc == stop_pc) |
| 494 | { |
| 495 | if (!bp->raw->inserted) |
| 496 | { |
| 497 | warning ("Hit a removed breakpoint?"); |
| 498 | return; |
| 499 | } |
| 500 | |
| 501 | if (bp->handler != NULL && (*bp->handler) (stop_pc)) |
| 502 | { |
| 503 | *bp_link = bp->next; |
| 504 | |
| 505 | release_breakpoint (proc, bp); |
| 506 | |
| 507 | bp = *bp_link; |
| 508 | continue; |
| 509 | } |
| 510 | } |
| 511 | |
| 512 | bp_link = &bp->next; |
| 513 | bp = *bp_link; |
| 514 | } |
| 515 | } |
| 516 | |
| 517 | void |
| 518 | set_breakpoint_data (const unsigned char *bp_data, int bp_len) |
| 519 | { |
| 520 | breakpoint_data = bp_data; |
| 521 | breakpoint_len = bp_len; |
| 522 | } |
| 523 | |
| 524 | int |
| 525 | breakpoint_here (CORE_ADDR addr) |
| 526 | { |
| 527 | return (find_raw_breakpoint_at (addr) != NULL); |
| 528 | } |
| 529 | |
| 530 | int |
| 531 | breakpoint_inserted_here (CORE_ADDR addr) |
| 532 | { |
| 533 | struct raw_breakpoint *bp; |
| 534 | |
| 535 | bp = find_raw_breakpoint_at (addr); |
| 536 | |
| 537 | return (bp != NULL && bp->inserted); |
| 538 | } |
| 539 | |
| 540 | void |
| 541 | check_mem_read (CORE_ADDR mem_addr, unsigned char *buf, int mem_len) |
| 542 | { |
| 543 | struct process_info *proc = current_process (); |
| 544 | struct raw_breakpoint *bp = proc->raw_breakpoints; |
| 545 | CORE_ADDR mem_end = mem_addr + mem_len; |
| 546 | |
| 547 | for (; bp != NULL; bp = bp->next) |
| 548 | { |
| 549 | CORE_ADDR bp_end = bp->pc + breakpoint_len; |
| 550 | CORE_ADDR start, end; |
| 551 | int copy_offset, copy_len, buf_offset; |
| 552 | |
| 553 | if (mem_addr >= bp_end) |
| 554 | continue; |
| 555 | if (bp->pc >= mem_end) |
| 556 | continue; |
| 557 | |
| 558 | start = bp->pc; |
| 559 | if (mem_addr > start) |
| 560 | start = mem_addr; |
| 561 | |
| 562 | end = bp_end; |
| 563 | if (end > mem_end) |
| 564 | end = mem_end; |
| 565 | |
| 566 | copy_len = end - start; |
| 567 | copy_offset = start - bp->pc; |
| 568 | buf_offset = start - mem_addr; |
| 569 | |
| 570 | if (bp->inserted) |
| 571 | memcpy (buf + buf_offset, bp->old_data + copy_offset, copy_len); |
| 572 | } |
| 573 | } |
| 574 | |
| 575 | void |
| 576 | check_mem_write (CORE_ADDR mem_addr, unsigned char *buf, int mem_len) |
| 577 | { |
| 578 | struct process_info *proc = current_process (); |
| 579 | struct raw_breakpoint *bp = proc->raw_breakpoints; |
| 580 | CORE_ADDR mem_end = mem_addr + mem_len; |
| 581 | |
| 582 | for (; bp != NULL; bp = bp->next) |
| 583 | { |
| 584 | CORE_ADDR bp_end = bp->pc + breakpoint_len; |
| 585 | CORE_ADDR start, end; |
| 586 | int copy_offset, copy_len, buf_offset; |
| 587 | |
| 588 | if (mem_addr >= bp_end) |
| 589 | continue; |
| 590 | if (bp->pc >= mem_end) |
| 591 | continue; |
| 592 | |
| 593 | start = bp->pc; |
| 594 | if (mem_addr > start) |
| 595 | start = mem_addr; |
| 596 | |
| 597 | end = bp_end; |
| 598 | if (end > mem_end) |
| 599 | end = mem_end; |
| 600 | |
| 601 | copy_len = end - start; |
| 602 | copy_offset = start - bp->pc; |
| 603 | buf_offset = start - mem_addr; |
| 604 | |
| 605 | memcpy (bp->old_data + copy_offset, buf + buf_offset, copy_len); |
| 606 | if (bp->inserted) |
| 607 | memcpy (buf + buf_offset, breakpoint_data + copy_offset, copy_len); |
| 608 | } |
| 609 | } |
| 610 | |
| 611 | /* Delete all breakpoints, and un-insert them from the inferior. */ |
| 612 | |
| 613 | void |
| 614 | delete_all_breakpoints (void) |
| 615 | { |
| 616 | struct process_info *proc = current_process (); |
| 617 | |
| 618 | while (proc->breakpoints) |
| 619 | delete_breakpoint_1 (proc, proc->breakpoints); |
| 620 | } |
| 621 | |
| 622 | /* Release all breakpoints, but do not try to un-insert them from the |
| 623 | inferior. */ |
| 624 | |
| 625 | void |
| 626 | free_all_breakpoints (struct process_info *proc) |
| 627 | { |
| 628 | struct raw_breakpoint *raw_bp; |
| 629 | |
| 630 | for (raw_bp = proc->raw_breakpoints; raw_bp != NULL; raw_bp = raw_bp->next) |
| 631 | raw_bp->inserted = 0; |
| 632 | |
| 633 | /* Note: use PROC explicitly instead of deferring to |
| 634 | delete_all_breakpoints --- CURRENT_INFERIOR may already have been |
| 635 | released when we get here. There should be no call to |
| 636 | current_process from here on. */ |
| 637 | while (proc->breakpoints) |
| 638 | delete_breakpoint_1 (proc, proc->breakpoints); |
| 639 | } |