Jason Wessel | 5d5314d | 2010-05-20 21:04:20 -0500 | [diff] [blame] | 1 | /* |
| 2 | * Kernel Debugger Architecture Independent Breakpoint Handler |
| 3 | * |
| 4 | * This file is subject to the terms and conditions of the GNU General Public |
| 5 | * License. See the file "COPYING" in the main directory of this archive |
| 6 | * for more details. |
| 7 | * |
| 8 | * Copyright (c) 1999-2004 Silicon Graphics, Inc. All Rights Reserved. |
| 9 | * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved. |
| 10 | */ |
| 11 | |
| 12 | #include <linux/string.h> |
| 13 | #include <linux/kernel.h> |
| 14 | #include <linux/init.h> |
| 15 | #include <linux/kdb.h> |
| 16 | #include <linux/kgdb.h> |
| 17 | #include <linux/smp.h> |
| 18 | #include <linux/sched.h> |
| 19 | #include <linux/interrupt.h> |
| 20 | #include "kdb_private.h" |
| 21 | |
| 22 | /* |
| 23 | * Table of kdb_breakpoints |
| 24 | */ |
| 25 | kdb_bp_t kdb_breakpoints[KDB_MAXBPT]; |
| 26 | |
| 27 | static void kdb_setsinglestep(struct pt_regs *regs) |
| 28 | { |
| 29 | KDB_STATE_SET(DOING_SS); |
| 30 | } |
| 31 | |
| 32 | static char *kdb_rwtypes[] = { |
| 33 | "Instruction(i)", |
| 34 | "Instruction(Register)", |
| 35 | "Data Write", |
| 36 | "I/O", |
| 37 | "Data Access" |
| 38 | }; |
| 39 | |
| 40 | static char *kdb_bptype(kdb_bp_t *bp) |
| 41 | { |
| 42 | if (bp->bp_type < 0 || bp->bp_type > 4) |
| 43 | return ""; |
| 44 | |
| 45 | return kdb_rwtypes[bp->bp_type]; |
| 46 | } |
| 47 | |
| 48 | static int kdb_parsebp(int argc, const char **argv, int *nextargp, kdb_bp_t *bp) |
| 49 | { |
| 50 | int nextarg = *nextargp; |
| 51 | int diag; |
| 52 | |
| 53 | bp->bph_length = 1; |
| 54 | if ((argc + 1) != nextarg) { |
| 55 | if (strnicmp(argv[nextarg], "datar", sizeof("datar")) == 0) |
| 56 | bp->bp_type = BP_ACCESS_WATCHPOINT; |
| 57 | else if (strnicmp(argv[nextarg], "dataw", sizeof("dataw")) == 0) |
| 58 | bp->bp_type = BP_WRITE_WATCHPOINT; |
| 59 | else if (strnicmp(argv[nextarg], "inst", sizeof("inst")) == 0) |
| 60 | bp->bp_type = BP_HARDWARE_BREAKPOINT; |
| 61 | else |
| 62 | return KDB_ARGCOUNT; |
| 63 | |
| 64 | bp->bph_length = 1; |
| 65 | |
| 66 | nextarg++; |
| 67 | |
| 68 | if ((argc + 1) != nextarg) { |
| 69 | unsigned long len; |
| 70 | |
| 71 | diag = kdbgetularg((char *)argv[nextarg], |
| 72 | &len); |
| 73 | if (diag) |
| 74 | return diag; |
| 75 | |
| 76 | |
| 77 | if (len > 8) |
| 78 | return KDB_BADLENGTH; |
| 79 | |
| 80 | bp->bph_length = len; |
| 81 | nextarg++; |
| 82 | } |
| 83 | |
| 84 | if ((argc + 1) != nextarg) |
| 85 | return KDB_ARGCOUNT; |
| 86 | } |
| 87 | |
| 88 | *nextargp = nextarg; |
| 89 | return 0; |
| 90 | } |
| 91 | |
| 92 | static int _kdb_bp_remove(kdb_bp_t *bp) |
| 93 | { |
| 94 | int ret = 1; |
| 95 | if (!bp->bp_installed) |
| 96 | return ret; |
| 97 | if (!bp->bp_type) |
| 98 | ret = dbg_remove_sw_break(bp->bp_addr); |
| 99 | else |
| 100 | ret = arch_kgdb_ops.remove_hw_breakpoint(bp->bp_addr, |
| 101 | bp->bph_length, |
| 102 | bp->bp_type); |
| 103 | if (ret == 0) |
| 104 | bp->bp_installed = 0; |
| 105 | return ret; |
| 106 | } |
| 107 | |
| 108 | static void kdb_handle_bp(struct pt_regs *regs, kdb_bp_t *bp) |
| 109 | { |
| 110 | if (KDB_DEBUG(BP)) |
| 111 | kdb_printf("regs->ip = 0x%lx\n", instruction_pointer(regs)); |
| 112 | |
| 113 | /* |
| 114 | * Setup single step |
| 115 | */ |
| 116 | kdb_setsinglestep(regs); |
| 117 | |
| 118 | /* |
| 119 | * Reset delay attribute |
| 120 | */ |
| 121 | bp->bp_delay = 0; |
| 122 | bp->bp_delayed = 1; |
| 123 | } |
| 124 | |
| 125 | static int _kdb_bp_install(struct pt_regs *regs, kdb_bp_t *bp) |
| 126 | { |
| 127 | int ret; |
| 128 | /* |
| 129 | * Install the breakpoint, if it is not already installed. |
| 130 | */ |
| 131 | |
| 132 | if (KDB_DEBUG(BP)) |
| 133 | kdb_printf("%s: bp_installed %d\n", |
| 134 | __func__, bp->bp_installed); |
| 135 | if (!KDB_STATE(SSBPT)) |
| 136 | bp->bp_delay = 0; |
| 137 | if (bp->bp_installed) |
| 138 | return 1; |
| 139 | if (bp->bp_delay || (bp->bp_delayed && KDB_STATE(DOING_SS))) { |
| 140 | if (KDB_DEBUG(BP)) |
| 141 | kdb_printf("%s: delayed bp\n", __func__); |
| 142 | kdb_handle_bp(regs, bp); |
| 143 | return 0; |
| 144 | } |
| 145 | if (!bp->bp_type) |
| 146 | ret = dbg_set_sw_break(bp->bp_addr); |
| 147 | else |
| 148 | ret = arch_kgdb_ops.set_hw_breakpoint(bp->bp_addr, |
| 149 | bp->bph_length, |
| 150 | bp->bp_type); |
| 151 | if (ret == 0) { |
| 152 | bp->bp_installed = 1; |
| 153 | } else { |
| 154 | kdb_printf("%s: failed to set breakpoint at 0x%lx\n", |
| 155 | __func__, bp->bp_addr); |
Jason Wessel | 1ba0c17 | 2011-09-21 13:07:47 -0700 | [diff] [blame] | 156 | #ifdef CONFIG_DEBUG_RODATA |
| 157 | if (!bp->bp_type) { |
| 158 | kdb_printf("Software breakpoints are unavailable.\n" |
| 159 | " Change the kernel CONFIG_DEBUG_RODATA=n\n" |
| 160 | " OR use hw breaks: help bph\n"); |
| 161 | } |
| 162 | #endif |
Jason Wessel | 5d5314d | 2010-05-20 21:04:20 -0500 | [diff] [blame] | 163 | return 1; |
| 164 | } |
| 165 | return 0; |
| 166 | } |
| 167 | |
| 168 | /* |
| 169 | * kdb_bp_install |
| 170 | * |
| 171 | * Install kdb_breakpoints prior to returning from the |
| 172 | * kernel debugger. This allows the kdb_breakpoints to be set |
| 173 | * upon functions that are used internally by kdb, such as |
| 174 | * printk(). This function is only called once per kdb session. |
| 175 | */ |
| 176 | void kdb_bp_install(struct pt_regs *regs) |
| 177 | { |
| 178 | int i; |
| 179 | |
| 180 | for (i = 0; i < KDB_MAXBPT; i++) { |
| 181 | kdb_bp_t *bp = &kdb_breakpoints[i]; |
| 182 | |
| 183 | if (KDB_DEBUG(BP)) { |
| 184 | kdb_printf("%s: bp %d bp_enabled %d\n", |
| 185 | __func__, i, bp->bp_enabled); |
| 186 | } |
| 187 | if (bp->bp_enabled) |
| 188 | _kdb_bp_install(regs, bp); |
| 189 | } |
| 190 | } |
| 191 | |
| 192 | /* |
| 193 | * kdb_bp_remove |
| 194 | * |
| 195 | * Remove kdb_breakpoints upon entry to the kernel debugger. |
| 196 | * |
| 197 | * Parameters: |
| 198 | * None. |
| 199 | * Outputs: |
| 200 | * None. |
| 201 | * Returns: |
| 202 | * None. |
| 203 | * Locking: |
| 204 | * None. |
| 205 | * Remarks: |
| 206 | */ |
| 207 | void kdb_bp_remove(void) |
| 208 | { |
| 209 | int i; |
| 210 | |
| 211 | for (i = KDB_MAXBPT - 1; i >= 0; i--) { |
| 212 | kdb_bp_t *bp = &kdb_breakpoints[i]; |
| 213 | |
| 214 | if (KDB_DEBUG(BP)) { |
| 215 | kdb_printf("%s: bp %d bp_enabled %d\n", |
| 216 | __func__, i, bp->bp_enabled); |
| 217 | } |
| 218 | if (bp->bp_enabled) |
| 219 | _kdb_bp_remove(bp); |
| 220 | } |
| 221 | } |
| 222 | |
| 223 | |
| 224 | /* |
| 225 | * kdb_printbp |
| 226 | * |
| 227 | * Internal function to format and print a breakpoint entry. |
| 228 | * |
| 229 | * Parameters: |
| 230 | * None. |
| 231 | * Outputs: |
| 232 | * None. |
| 233 | * Returns: |
| 234 | * None. |
| 235 | * Locking: |
| 236 | * None. |
| 237 | * Remarks: |
| 238 | */ |
| 239 | |
| 240 | static void kdb_printbp(kdb_bp_t *bp, int i) |
| 241 | { |
| 242 | kdb_printf("%s ", kdb_bptype(bp)); |
| 243 | kdb_printf("BP #%d at ", i); |
| 244 | kdb_symbol_print(bp->bp_addr, NULL, KDB_SP_DEFAULT); |
| 245 | |
| 246 | if (bp->bp_enabled) |
| 247 | kdb_printf("\n is enabled"); |
| 248 | else |
| 249 | kdb_printf("\n is disabled"); |
| 250 | |
| 251 | kdb_printf("\taddr at %016lx, hardtype=%d installed=%d\n", |
| 252 | bp->bp_addr, bp->bp_type, bp->bp_installed); |
| 253 | |
| 254 | kdb_printf("\n"); |
| 255 | } |
| 256 | |
| 257 | /* |
| 258 | * kdb_bp |
| 259 | * |
| 260 | * Handle the bp commands. |
| 261 | * |
| 262 | * [bp|bph] <addr-expression> [DATAR|DATAW] |
| 263 | * |
| 264 | * Parameters: |
| 265 | * argc Count of arguments in argv |
| 266 | * argv Space delimited command line arguments |
| 267 | * Outputs: |
| 268 | * None. |
| 269 | * Returns: |
| 270 | * Zero for success, a kdb diagnostic if failure. |
| 271 | * Locking: |
| 272 | * None. |
| 273 | * Remarks: |
| 274 | * |
| 275 | * bp Set breakpoint on all cpus. Only use hardware assist if need. |
| 276 | * bph Set breakpoint on all cpus. Force hardware register |
| 277 | */ |
| 278 | |
| 279 | static int kdb_bp(int argc, const char **argv) |
| 280 | { |
| 281 | int i, bpno; |
| 282 | kdb_bp_t *bp, *bp_check; |
| 283 | int diag; |
Jason Wessel | 5d5314d | 2010-05-20 21:04:20 -0500 | [diff] [blame] | 284 | char *symname = NULL; |
| 285 | long offset = 0ul; |
| 286 | int nextarg; |
| 287 | kdb_bp_t template = {0}; |
| 288 | |
| 289 | if (argc == 0) { |
| 290 | /* |
| 291 | * Display breakpoint table |
| 292 | */ |
| 293 | for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT; |
| 294 | bpno++, bp++) { |
| 295 | if (bp->bp_free) |
| 296 | continue; |
| 297 | kdb_printbp(bp, bpno); |
| 298 | } |
| 299 | |
| 300 | return 0; |
| 301 | } |
| 302 | |
| 303 | nextarg = 1; |
| 304 | diag = kdbgetaddrarg(argc, argv, &nextarg, &template.bp_addr, |
| 305 | &offset, &symname); |
| 306 | if (diag) |
| 307 | return diag; |
| 308 | if (!template.bp_addr) |
| 309 | return KDB_BADINT; |
| 310 | |
| 311 | /* |
| 312 | * Find an empty bp structure to allocate |
| 313 | */ |
Jason Wessel | 5d5314d | 2010-05-20 21:04:20 -0500 | [diff] [blame] | 314 | for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT; bpno++, bp++) { |
| 315 | if (bp->bp_free) |
| 316 | break; |
| 317 | } |
| 318 | |
| 319 | if (bpno == KDB_MAXBPT) |
| 320 | return KDB_TOOMANYBPT; |
| 321 | |
| 322 | if (strcmp(argv[0], "bph") == 0) { |
| 323 | template.bp_type = BP_HARDWARE_BREAKPOINT; |
| 324 | diag = kdb_parsebp(argc, argv, &nextarg, &template); |
| 325 | if (diag) |
| 326 | return diag; |
| 327 | } else { |
| 328 | template.bp_type = BP_BREAKPOINT; |
| 329 | } |
| 330 | |
| 331 | /* |
| 332 | * Check for clashing breakpoints. |
| 333 | * |
| 334 | * Note, in this design we can't have hardware breakpoints |
| 335 | * enabled for both read and write on the same address. |
| 336 | */ |
| 337 | for (i = 0, bp_check = kdb_breakpoints; i < KDB_MAXBPT; |
| 338 | i++, bp_check++) { |
| 339 | if (!bp_check->bp_free && |
| 340 | bp_check->bp_addr == template.bp_addr) { |
| 341 | kdb_printf("You already have a breakpoint at " |
| 342 | kdb_bfd_vma_fmt0 "\n", template.bp_addr); |
| 343 | return KDB_DUPBPT; |
| 344 | } |
| 345 | } |
| 346 | |
| 347 | template.bp_enabled = 1; |
| 348 | |
| 349 | /* |
| 350 | * Actually allocate the breakpoint found earlier |
| 351 | */ |
| 352 | *bp = template; |
| 353 | bp->bp_free = 0; |
| 354 | |
| 355 | kdb_printbp(bp, bpno); |
| 356 | |
| 357 | return 0; |
| 358 | } |
| 359 | |
| 360 | /* |
| 361 | * kdb_bc |
| 362 | * |
| 363 | * Handles the 'bc', 'be', and 'bd' commands |
| 364 | * |
| 365 | * [bd|bc|be] <breakpoint-number> |
| 366 | * [bd|bc|be] * |
| 367 | * |
| 368 | * Parameters: |
| 369 | * argc Count of arguments in argv |
| 370 | * argv Space delimited command line arguments |
| 371 | * Outputs: |
| 372 | * None. |
| 373 | * Returns: |
| 374 | * Zero for success, a kdb diagnostic for failure |
| 375 | * Locking: |
| 376 | * None. |
| 377 | * Remarks: |
| 378 | */ |
| 379 | static int kdb_bc(int argc, const char **argv) |
| 380 | { |
| 381 | unsigned long addr; |
| 382 | kdb_bp_t *bp = NULL; |
| 383 | int lowbp = KDB_MAXBPT; |
| 384 | int highbp = 0; |
| 385 | int done = 0; |
| 386 | int i; |
| 387 | int diag = 0; |
| 388 | |
| 389 | int cmd; /* KDBCMD_B? */ |
| 390 | #define KDBCMD_BC 0 |
| 391 | #define KDBCMD_BE 1 |
| 392 | #define KDBCMD_BD 2 |
| 393 | |
| 394 | if (strcmp(argv[0], "be") == 0) |
| 395 | cmd = KDBCMD_BE; |
| 396 | else if (strcmp(argv[0], "bd") == 0) |
| 397 | cmd = KDBCMD_BD; |
| 398 | else |
| 399 | cmd = KDBCMD_BC; |
| 400 | |
| 401 | if (argc != 1) |
| 402 | return KDB_ARGCOUNT; |
| 403 | |
| 404 | if (strcmp(argv[1], "*") == 0) { |
| 405 | lowbp = 0; |
| 406 | highbp = KDB_MAXBPT; |
| 407 | } else { |
| 408 | diag = kdbgetularg(argv[1], &addr); |
| 409 | if (diag) |
| 410 | return diag; |
| 411 | |
| 412 | /* |
| 413 | * For addresses less than the maximum breakpoint number, |
| 414 | * assume that the breakpoint number is desired. |
| 415 | */ |
| 416 | if (addr < KDB_MAXBPT) { |
| 417 | bp = &kdb_breakpoints[addr]; |
| 418 | lowbp = highbp = addr; |
| 419 | highbp++; |
| 420 | } else { |
| 421 | for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; |
| 422 | i++, bp++) { |
| 423 | if (bp->bp_addr == addr) { |
| 424 | lowbp = highbp = i; |
| 425 | highbp++; |
| 426 | break; |
| 427 | } |
| 428 | } |
| 429 | } |
| 430 | } |
| 431 | |
| 432 | /* |
| 433 | * Now operate on the set of breakpoints matching the input |
| 434 | * criteria (either '*' for all, or an individual breakpoint). |
| 435 | */ |
| 436 | for (bp = &kdb_breakpoints[lowbp], i = lowbp; |
| 437 | i < highbp; |
| 438 | i++, bp++) { |
| 439 | if (bp->bp_free) |
| 440 | continue; |
| 441 | |
| 442 | done++; |
| 443 | |
| 444 | switch (cmd) { |
| 445 | case KDBCMD_BC: |
| 446 | bp->bp_enabled = 0; |
| 447 | |
| 448 | kdb_printf("Breakpoint %d at " |
| 449 | kdb_bfd_vma_fmt " cleared\n", |
| 450 | i, bp->bp_addr); |
| 451 | |
| 452 | bp->bp_addr = 0; |
| 453 | bp->bp_free = 1; |
| 454 | |
| 455 | break; |
| 456 | case KDBCMD_BE: |
| 457 | bp->bp_enabled = 1; |
| 458 | |
| 459 | kdb_printf("Breakpoint %d at " |
| 460 | kdb_bfd_vma_fmt " enabled", |
| 461 | i, bp->bp_addr); |
| 462 | |
| 463 | kdb_printf("\n"); |
| 464 | break; |
| 465 | case KDBCMD_BD: |
| 466 | if (!bp->bp_enabled) |
| 467 | break; |
| 468 | |
| 469 | bp->bp_enabled = 0; |
| 470 | |
| 471 | kdb_printf("Breakpoint %d at " |
| 472 | kdb_bfd_vma_fmt " disabled\n", |
| 473 | i, bp->bp_addr); |
| 474 | |
| 475 | break; |
| 476 | } |
| 477 | if (bp->bp_delay && (cmd == KDBCMD_BC || cmd == KDBCMD_BD)) { |
| 478 | bp->bp_delay = 0; |
| 479 | KDB_STATE_CLEAR(SSBPT); |
| 480 | } |
| 481 | } |
| 482 | |
| 483 | return (!done) ? KDB_BPTNOTFOUND : 0; |
| 484 | } |
| 485 | |
| 486 | /* |
| 487 | * kdb_ss |
| 488 | * |
| 489 | * Process the 'ss' (Single Step) and 'ssb' (Single Step to Branch) |
| 490 | * commands. |
| 491 | * |
| 492 | * ss |
| 493 | * ssb |
| 494 | * |
| 495 | * Parameters: |
| 496 | * argc Argument count |
| 497 | * argv Argument vector |
| 498 | * Outputs: |
| 499 | * None. |
| 500 | * Returns: |
| 501 | * KDB_CMD_SS[B] for success, a kdb error if failure. |
| 502 | * Locking: |
| 503 | * None. |
| 504 | * Remarks: |
| 505 | * |
| 506 | * Set the arch specific option to trigger a debug trap after the next |
| 507 | * instruction. |
| 508 | * |
| 509 | * For 'ssb', set the trace flag in the debug trap handler |
| 510 | * after printing the current insn and return directly without |
| 511 | * invoking the kdb command processor, until a branch instruction |
| 512 | * is encountered. |
| 513 | */ |
| 514 | |
| 515 | static int kdb_ss(int argc, const char **argv) |
| 516 | { |
| 517 | int ssb = 0; |
| 518 | |
| 519 | ssb = (strcmp(argv[0], "ssb") == 0); |
| 520 | if (argc != 0) |
| 521 | return KDB_ARGCOUNT; |
| 522 | /* |
| 523 | * Set trace flag and go. |
| 524 | */ |
| 525 | KDB_STATE_SET(DOING_SS); |
| 526 | if (ssb) { |
| 527 | KDB_STATE_SET(DOING_SSB); |
| 528 | return KDB_CMD_SSB; |
| 529 | } |
| 530 | return KDB_CMD_SS; |
| 531 | } |
| 532 | |
| 533 | /* Initialize the breakpoint table and register breakpoint commands. */ |
| 534 | |
| 535 | void __init kdb_initbptab(void) |
| 536 | { |
| 537 | int i; |
| 538 | kdb_bp_t *bp; |
| 539 | |
| 540 | /* |
| 541 | * First time initialization. |
| 542 | */ |
| 543 | memset(&kdb_breakpoints, '\0', sizeof(kdb_breakpoints)); |
| 544 | |
| 545 | for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) |
| 546 | bp->bp_free = 1; |
| 547 | |
| 548 | kdb_register_repeat("bp", kdb_bp, "[<vaddr>]", |
| 549 | "Set/Display breakpoints", 0, KDB_REPEAT_NO_ARGS); |
| 550 | kdb_register_repeat("bl", kdb_bp, "[<vaddr>]", |
| 551 | "Display breakpoints", 0, KDB_REPEAT_NO_ARGS); |
| 552 | if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT) |
| 553 | kdb_register_repeat("bph", kdb_bp, "[<vaddr>]", |
| 554 | "[datar [length]|dataw [length]] Set hw brk", 0, KDB_REPEAT_NO_ARGS); |
| 555 | kdb_register_repeat("bc", kdb_bc, "<bpnum>", |
| 556 | "Clear Breakpoint", 0, KDB_REPEAT_NONE); |
| 557 | kdb_register_repeat("be", kdb_bc, "<bpnum>", |
| 558 | "Enable Breakpoint", 0, KDB_REPEAT_NONE); |
| 559 | kdb_register_repeat("bd", kdb_bc, "<bpnum>", |
| 560 | "Disable Breakpoint", 0, KDB_REPEAT_NONE); |
| 561 | |
| 562 | kdb_register_repeat("ss", kdb_ss, "", |
| 563 | "Single Step", 1, KDB_REPEAT_NO_ARGS); |
| 564 | kdb_register_repeat("ssb", kdb_ss, "", |
| 565 | "Single step to branch/call", 0, KDB_REPEAT_NO_ARGS); |
| 566 | /* |
| 567 | * Architecture dependent initialization. |
| 568 | */ |
| 569 | } |