Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/amd64/amd64/db_trace.c
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1 /*- 2 * Mach Operating System 3 * Copyright (c) 1991,1990 Carnegie Mellon University 4 * All Rights Reserved. 5 * 6 * Permission to use, copy, modify and distribute this software and its 7 * documentation is hereby granted, provided that both the copyright 8 * notice and this permission notice appear in all copies of the 9 * software, derivative works or modified versions, and any portions 10 * thereof, and that both notices appear in supporting documentation. 11 * 12 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS 13 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR 14 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 15 * 16 * Carnegie Mellon requests users of this software to return to 17 * 18 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 19 * School of Computer Science 20 * Carnegie Mellon University 21 * Pittsburgh PA 15213-3890 22 * 23 * any improvements or extensions that they make and grant Carnegie the 24 * rights to redistribute these changes. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD: releng/6.0/sys/amd64/amd64/db_trace.c 149760 2005-09-03 11:57:28Z jkoshy $"); 29 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/kdb.h> 33 #include <sys/proc.h> 34 #include <sys/sysent.h> 35 36 #include <machine/cpu.h> 37 #include <machine/md_var.h> 38 #include <machine/pcb.h> 39 #include <machine/reg.h> 40 41 #include <vm/vm.h> 42 #include <vm/vm_param.h> 43 #include <vm/pmap.h> 44 45 #include <ddb/ddb.h> 46 #include <ddb/db_access.h> 47 #include <ddb/db_sym.h> 48 #include <ddb/db_variables.h> 49 50 static db_varfcn_t db_dr0; 51 static db_varfcn_t db_dr1; 52 static db_varfcn_t db_dr2; 53 static db_varfcn_t db_dr3; 54 static db_varfcn_t db_dr4; 55 static db_varfcn_t db_dr5; 56 static db_varfcn_t db_dr6; 57 static db_varfcn_t db_dr7; 58 static db_varfcn_t db_frame; 59 static db_varfcn_t db_rsp; 60 static db_varfcn_t db_ss; 61 62 /* 63 * Machine register set. 64 */ 65 #define DB_OFFSET(x) (db_expr_t *)offsetof(struct trapframe, x) 66 struct db_variable db_regs[] = { 67 { "cs", DB_OFFSET(tf_cs), db_frame }, 68 #if 0 69 { "ds", DB_OFFSET(tf_ds), db_frame }, 70 { "es", DB_OFFSET(tf_es), db_frame }, 71 { "fs", DB_OFFSET(tf_fs), db_frame }, 72 { "gs", DB_OFFSET(tf_gs), db_frame }, 73 #endif 74 { "ss", NULL, db_ss }, 75 { "rax", DB_OFFSET(tf_rax), db_frame }, 76 { "rcx", DB_OFFSET(tf_rcx), db_frame }, 77 { "rdx", DB_OFFSET(tf_rdx), db_frame }, 78 { "rbx", DB_OFFSET(tf_rbx), db_frame }, 79 { "rsp", NULL, db_rsp }, 80 { "rbp", DB_OFFSET(tf_rbp), db_frame }, 81 { "rsi", DB_OFFSET(tf_rsi), db_frame }, 82 { "rdi", DB_OFFSET(tf_rdi), db_frame }, 83 { "r8", DB_OFFSET(tf_r8), db_frame }, 84 { "r9", DB_OFFSET(tf_r9), db_frame }, 85 { "r10", DB_OFFSET(tf_r10), db_frame }, 86 { "r11", DB_OFFSET(tf_r11), db_frame }, 87 { "r12", DB_OFFSET(tf_r12), db_frame }, 88 { "r13", DB_OFFSET(tf_r13), db_frame }, 89 { "r14", DB_OFFSET(tf_r14), db_frame }, 90 { "r15", DB_OFFSET(tf_r15), db_frame }, 91 { "rip", DB_OFFSET(tf_rip), db_frame }, 92 { "rflags", DB_OFFSET(tf_rflags), db_frame }, 93 { "dr0", NULL, db_dr0 }, 94 { "dr1", NULL, db_dr1 }, 95 { "dr2", NULL, db_dr2 }, 96 { "dr3", NULL, db_dr3 }, 97 { "dr4", NULL, db_dr4 }, 98 { "dr5", NULL, db_dr5 }, 99 { "dr6", NULL, db_dr6 }, 100 { "dr7", NULL, db_dr7 }, 101 }; 102 struct db_variable *db_eregs = db_regs + sizeof(db_regs)/sizeof(db_regs[0]); 103 104 #define DB_DRX_FUNC(reg) \ 105 static int \ 106 db_ ## reg (vp, valuep, op) \ 107 struct db_variable *vp; \ 108 db_expr_t * valuep; \ 109 int op; \ 110 { \ 111 if (op == DB_VAR_GET) \ 112 *valuep = r ## reg (); \ 113 else \ 114 load_ ## reg (*valuep); \ 115 return (1); \ 116 } 117 118 DB_DRX_FUNC(dr0) 119 DB_DRX_FUNC(dr1) 120 DB_DRX_FUNC(dr2) 121 DB_DRX_FUNC(dr3) 122 DB_DRX_FUNC(dr4) 123 DB_DRX_FUNC(dr5) 124 DB_DRX_FUNC(dr6) 125 DB_DRX_FUNC(dr7) 126 127 static __inline long 128 get_rsp(struct trapframe *tf) 129 { 130 return ((ISPL(tf->tf_cs)) ? tf->tf_rsp : 131 (db_expr_t)tf + offsetof(struct trapframe, tf_rsp)); 132 } 133 134 static int 135 db_frame(struct db_variable *vp, db_expr_t *valuep, int op) 136 { 137 long *reg; 138 139 if (kdb_frame == NULL) 140 return (0); 141 142 reg = (long *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep); 143 if (op == DB_VAR_GET) 144 *valuep = *reg; 145 else 146 *reg = *valuep; 147 return (1); 148 } 149 150 static int 151 db_rsp(struct db_variable *vp, db_expr_t *valuep, int op) 152 { 153 154 if (kdb_frame == NULL) 155 return (0); 156 157 if (op == DB_VAR_GET) 158 *valuep = get_rsp(kdb_frame); 159 else if (ISPL(kdb_frame->tf_cs)) 160 kdb_frame->tf_rsp = *valuep; 161 return (1); 162 } 163 164 static int 165 db_ss(struct db_variable *vp, db_expr_t *valuep, int op) 166 { 167 168 if (kdb_frame == NULL) 169 return (0); 170 171 if (op == DB_VAR_GET) 172 *valuep = (ISPL(kdb_frame->tf_cs)) ? kdb_frame->tf_ss : rss(); 173 else if (ISPL(kdb_frame->tf_cs)) 174 kdb_frame->tf_ss = *valuep; 175 return (1); 176 } 177 178 /* 179 * Stack trace. 180 */ 181 #define INKERNEL(va) (((vm_offset_t)(va)) >= USRSTACK) 182 183 struct amd64_frame { 184 struct amd64_frame *f_frame; 185 long f_retaddr; 186 long f_arg0; 187 }; 188 189 #define NORMAL 0 190 #define TRAP 1 191 #define INTERRUPT 2 192 #define SYSCALL 3 193 194 static void db_nextframe(struct amd64_frame **, db_addr_t *, struct thread *); 195 static int db_numargs(struct amd64_frame *); 196 static void db_print_stack_entry(const char *, int, char **, long *, db_addr_t); 197 static void decode_syscall(int, struct thread *); 198 199 static char * watchtype_str(int type); 200 int amd64_set_watch(int watchnum, unsigned int watchaddr, int size, int access, 201 struct dbreg * d); 202 int amd64_clr_watch(int watchnum, struct dbreg * d); 203 int db_md_set_watchpoint(db_expr_t addr, db_expr_t size); 204 int db_md_clr_watchpoint(db_expr_t addr, db_expr_t size); 205 void db_md_list_watchpoints(void); 206 207 /* 208 * Figure out how many arguments were passed into the frame at "fp". 209 */ 210 static int 211 db_numargs(fp) 212 struct amd64_frame *fp; 213 { 214 #if 1 215 return (0); /* regparm, needs dwarf2 info */ 216 #else 217 long *argp; 218 int inst; 219 int args; 220 221 argp = (long *)db_get_value((long)&fp->f_retaddr, 8, FALSE); 222 /* 223 * XXX etext is wrong for LKMs. We should attempt to interpret 224 * the instruction at the return address in all cases. This 225 * may require better fault handling. 226 */ 227 if (argp < (long *)btext || argp >= (long *)etext) { 228 args = 5; 229 } else { 230 inst = db_get_value((long)argp, 4, FALSE); 231 if ((inst & 0xff) == 0x59) /* popl %ecx */ 232 args = 1; 233 else if ((inst & 0xffff) == 0xc483) /* addl $Ibs, %esp */ 234 args = ((inst >> 16) & 0xff) / 4; 235 else 236 args = 5; 237 } 238 return (args); 239 #endif 240 } 241 242 static void 243 db_print_stack_entry(name, narg, argnp, argp, callpc) 244 const char *name; 245 int narg; 246 char **argnp; 247 long *argp; 248 db_addr_t callpc; 249 { 250 db_printf("%s(", name); 251 #if 0 252 while (narg) { 253 if (argnp) 254 db_printf("%s=", *argnp++); 255 db_printf("%lr", (long)db_get_value((long)argp, 8, FALSE)); 256 argp++; 257 if (--narg != 0) 258 db_printf(","); 259 } 260 #endif 261 db_printf(") at "); 262 db_printsym(callpc, DB_STGY_PROC); 263 db_printf("\n"); 264 } 265 266 static void 267 decode_syscall(int number, struct thread *td) 268 { 269 struct proc *p; 270 c_db_sym_t sym; 271 db_expr_t diff; 272 sy_call_t *f; 273 const char *symname; 274 275 db_printf(" (%d", number); 276 p = (td != NULL) ? td->td_proc : NULL; 277 if (p != NULL && 0 <= number && number < p->p_sysent->sv_size) { 278 f = p->p_sysent->sv_table[number].sy_call; 279 sym = db_search_symbol((db_addr_t)f, DB_STGY_ANY, &diff); 280 if (sym != DB_SYM_NULL && diff == 0) { 281 db_symbol_values(sym, &symname, NULL); 282 db_printf(", %s, %s", p->p_sysent->sv_name, symname); 283 } 284 } 285 db_printf(")"); 286 } 287 288 /* 289 * Figure out the next frame up in the call stack. 290 */ 291 static void 292 db_nextframe(struct amd64_frame **fp, db_addr_t *ip, struct thread *td) 293 { 294 struct trapframe *tf; 295 int frame_type; 296 long rip, rsp, rbp; 297 db_expr_t offset; 298 c_db_sym_t sym; 299 const char *name; 300 301 rip = db_get_value((long) &(*fp)->f_retaddr, 8, FALSE); 302 rbp = db_get_value((long) &(*fp)->f_frame, 8, FALSE); 303 304 /* 305 * Figure out frame type. We look at the address just before 306 * the saved instruction pointer as the saved EIP is after the 307 * call function, and if the function being called is marked as 308 * dead (such as panic() at the end of dblfault_handler()), then 309 * the instruction at the saved EIP will be part of a different 310 * function (syscall() in this example) rather than the one that 311 * actually made the call. 312 */ 313 frame_type = NORMAL; 314 sym = db_search_symbol(rip - 1, DB_STGY_ANY, &offset); 315 db_symbol_values(sym, &name, NULL); 316 if (name != NULL) { 317 if (strcmp(name, "calltrap") == 0 || 318 strcmp(name, "fork_trampoline") == 0 || 319 strcmp(name, "nmi_calltrap") == 0) 320 frame_type = TRAP; 321 else if (strncmp(name, "Xatpic_intr", 11) == 0 || 322 strncmp(name, "Xatpic_fastintr", 15) == 0 || 323 strncmp(name, "Xapic_isr", 9) == 0) 324 frame_type = INTERRUPT; 325 else if (strcmp(name, "Xfast_syscall") == 0) 326 frame_type = SYSCALL; 327 } 328 329 /* 330 * Normal frames need no special processing. 331 */ 332 if (frame_type == NORMAL) { 333 *ip = (db_addr_t) rip; 334 *fp = (struct amd64_frame *) rbp; 335 return; 336 } 337 338 db_print_stack_entry(name, 0, 0, 0, rip); 339 340 /* 341 * Point to base of trapframe which is just above the 342 * current frame. 343 */ 344 tf = (struct trapframe *)((long)*fp + 16); 345 346 if (INKERNEL((long) tf)) { 347 rsp = get_rsp(tf); 348 rip = tf->tf_rip; 349 rbp = tf->tf_rbp; 350 switch (frame_type) { 351 case TRAP: 352 db_printf("--- trap %#lr", tf->tf_trapno); 353 break; 354 case SYSCALL: 355 db_printf("--- syscall"); 356 decode_syscall(tf->tf_rax, td); 357 break; 358 case INTERRUPT: 359 db_printf("--- interrupt"); 360 break; 361 default: 362 panic("The moon has moved again."); 363 } 364 db_printf(", rip = %#lr, rsp = %#lr, rbp = %#lr ---\n", rip, 365 rsp, rbp); 366 } 367 368 *ip = (db_addr_t) rip; 369 *fp = (struct amd64_frame *) rbp; 370 } 371 372 static int 373 db_backtrace(struct thread *td, struct trapframe *tf, 374 struct amd64_frame *frame, db_addr_t pc, int count) 375 { 376 struct amd64_frame *actframe; 377 #define MAXNARG 16 378 char *argnames[MAXNARG], **argnp = NULL; 379 const char *name; 380 long *argp; 381 db_expr_t offset; 382 c_db_sym_t sym; 383 int narg, quit; 384 boolean_t first; 385 386 if (count == -1) 387 count = 1024; 388 389 first = TRUE; 390 quit = 0; 391 db_setup_paging(db_simple_pager, &quit, db_lines_per_page); 392 while (count-- && !quit) { 393 sym = db_search_symbol(pc, DB_STGY_ANY, &offset); 394 db_symbol_values(sym, &name, NULL); 395 396 /* 397 * Attempt to determine a (possibly fake) frame that gives 398 * the caller's pc. It may differ from `frame' if the 399 * current function never sets up a standard frame or hasn't 400 * set one up yet or has just discarded one. The last two 401 * cases can be guessed fairly reliably for code generated 402 * by gcc. The first case is too much trouble to handle in 403 * general because the amount of junk on the stack depends 404 * on the pc (the special handling of "calltrap", etc. in 405 * db_nextframe() works because the `next' pc is special). 406 */ 407 actframe = frame; 408 if (first) { 409 if (tf != NULL) { 410 int instr; 411 412 instr = db_get_value(pc, 4, FALSE); 413 if ((instr & 0xffffffff) == 0xe5894855) { 414 /* pushq %rbp; movq %rsp, %rbp */ 415 actframe = (void *)(get_rsp(tf) - 8); 416 } else if ((instr & 0xffffff) == 0xe58948) { 417 /* movq %rsp, %rbp */ 418 actframe = (void *)get_rsp(tf); 419 if (tf->tf_rbp == 0) { 420 /* Fake frame better. */ 421 frame = actframe; 422 } 423 } else if ((instr & 0xff) == 0xc3) { 424 /* ret */ 425 actframe = (void *)(get_rsp(tf) - 8); 426 } else if (offset == 0) { 427 /* Probably an assembler symbol. */ 428 actframe = (void *)(get_rsp(tf) - 8); 429 } 430 } else if (strcmp(name, "fork_trampoline") == 0) { 431 /* 432 * Don't try to walk back on a stack for a 433 * process that hasn't actually been run yet. 434 */ 435 db_print_stack_entry(name, 0, 0, 0, pc); 436 break; 437 } 438 first = FALSE; 439 } 440 441 argp = &actframe->f_arg0; 442 narg = MAXNARG; 443 if (sym != NULL && db_sym_numargs(sym, &narg, argnames)) { 444 argnp = argnames; 445 } else { 446 narg = db_numargs(frame); 447 } 448 449 db_print_stack_entry(name, narg, argnp, argp, pc); 450 451 if (actframe != frame) { 452 /* `frame' belongs to caller. */ 453 pc = (db_addr_t) 454 db_get_value((long)&actframe->f_retaddr, 8, FALSE); 455 continue; 456 } 457 458 db_nextframe(&frame, &pc, td); 459 460 if (INKERNEL((long)pc) && !INKERNEL((long)frame)) { 461 sym = db_search_symbol(pc, DB_STGY_ANY, &offset); 462 db_symbol_values(sym, &name, NULL); 463 db_print_stack_entry(name, 0, 0, 0, pc); 464 break; 465 } 466 if (!INKERNEL((long) frame)) { 467 break; 468 } 469 } 470 471 return (0); 472 } 473 474 void 475 db_trace_self(void) 476 { 477 struct amd64_frame *frame; 478 db_addr_t callpc; 479 register_t rbp; 480 481 __asm __volatile("movq %%rbp,%0" : "=r" (rbp)); 482 frame = (struct amd64_frame *)rbp; 483 callpc = (db_addr_t)db_get_value((long)&frame->f_retaddr, 8, FALSE); 484 frame = frame->f_frame; 485 db_backtrace(curthread, NULL, frame, callpc, -1); 486 } 487 488 int 489 db_trace_thread(struct thread *thr, int count) 490 { 491 struct pcb *ctx; 492 493 ctx = kdb_thr_ctx(thr); 494 return (db_backtrace(thr, NULL, (struct amd64_frame *)ctx->pcb_rbp, 495 ctx->pcb_rip, count)); 496 } 497 498 int 499 amd64_set_watch(watchnum, watchaddr, size, access, d) 500 int watchnum; 501 unsigned int watchaddr; 502 int size; 503 int access; 504 struct dbreg * d; 505 { 506 int i; 507 unsigned int mask; 508 509 if (watchnum == -1) { 510 for (i = 0, mask = 0x3; i < 4; i++, mask <<= 2) 511 if ((d->dr[7] & mask) == 0) 512 break; 513 if (i < 4) 514 watchnum = i; 515 else 516 return (-1); 517 } 518 519 switch (access) { 520 case DBREG_DR7_EXEC: 521 size = 1; /* size must be 1 for an execution breakpoint */ 522 /* fall through */ 523 case DBREG_DR7_WRONLY: 524 case DBREG_DR7_RDWR: 525 break; 526 default : return (-1); 527 } 528 529 /* 530 * we can watch a 1, 2, or 4 byte sized location 531 */ 532 switch (size) { 533 case 1 : mask = 0x00; break; 534 case 2 : mask = 0x01 << 2; break; 535 case 4 : mask = 0x03 << 2; break; 536 default : return (-1); 537 } 538 539 mask |= access; 540 541 /* clear the bits we are about to affect */ 542 d->dr[7] &= ~((0x3 << (watchnum*2)) | (0x0f << (watchnum*4+16))); 543 544 /* set drN register to the address, N=watchnum */ 545 DBREG_DRX(d,watchnum) = watchaddr; 546 547 /* enable the watchpoint */ 548 d->dr[7] |= (0x2 << (watchnum*2)) | (mask << (watchnum*4+16)); 549 550 return (watchnum); 551 } 552 553 554 int 555 amd64_clr_watch(watchnum, d) 556 int watchnum; 557 struct dbreg * d; 558 { 559 560 if (watchnum < 0 || watchnum >= 4) 561 return (-1); 562 563 d->dr[7] = d->dr[7] & ~((0x3 << (watchnum*2)) | (0x0f << (watchnum*4+16))); 564 DBREG_DRX(d,watchnum) = 0; 565 566 return (0); 567 } 568 569 570 int 571 db_md_set_watchpoint(addr, size) 572 db_expr_t addr; 573 db_expr_t size; 574 { 575 int avail, wsize; 576 int i; 577 struct dbreg d; 578 579 fill_dbregs(NULL, &d); 580 581 avail = 0; 582 for(i=0; i<4; i++) { 583 if ((d.dr[7] & (3 << (i*2))) == 0) 584 avail++; 585 } 586 587 if (avail*4 < size) 588 return (-1); 589 590 for (i=0; i<4 && (size != 0); i++) { 591 if ((d.dr[7] & (3<<(i*2))) == 0) { 592 if (size > 4) 593 wsize = 4; 594 else 595 wsize = size; 596 if (wsize == 3) 597 wsize++; 598 amd64_set_watch(i, addr, wsize, 599 DBREG_DR7_WRONLY, &d); 600 addr += wsize; 601 size -= wsize; 602 } 603 } 604 605 set_dbregs(NULL, &d); 606 607 return(0); 608 } 609 610 611 int 612 db_md_clr_watchpoint(addr, size) 613 db_expr_t addr; 614 db_expr_t size; 615 { 616 int i; 617 struct dbreg d; 618 619 fill_dbregs(NULL, &d); 620 621 for(i=0; i<4; i++) { 622 if (d.dr[7] & (3 << (i*2))) { 623 if ((DBREG_DRX((&d), i) >= addr) && 624 (DBREG_DRX((&d), i) < addr+size)) 625 amd64_clr_watch(i, &d); 626 627 } 628 } 629 630 set_dbregs(NULL, &d); 631 632 return(0); 633 } 634 635 636 static 637 char * 638 watchtype_str(type) 639 int type; 640 { 641 switch (type) { 642 case DBREG_DR7_EXEC : return "execute"; break; 643 case DBREG_DR7_RDWR : return "read/write"; break; 644 case DBREG_DR7_WRONLY : return "write"; break; 645 default : return "invalid"; break; 646 } 647 } 648 649 650 void 651 db_md_list_watchpoints() 652 { 653 int i; 654 struct dbreg d; 655 656 fill_dbregs(NULL, &d); 657 658 db_printf("\nhardware watchpoints:\n"); 659 db_printf(" watch status type len address\n"); 660 db_printf(" ----- -------- ---------- --- ----------\n"); 661 for (i=0; i<4; i++) { 662 if (d.dr[7] & (0x03 << (i*2))) { 663 unsigned type, len; 664 type = (d.dr[7] >> (16+(i*4))) & 3; 665 len = (d.dr[7] >> (16+(i*4)+2)) & 3; 666 db_printf(" %-5d %-8s %10s %3d 0x%016lx\n", 667 i, "enabled", watchtype_str(type), 668 len + 1, DBREG_DRX((&d), i)); 669 } 670 else { 671 db_printf(" %-5d disabled\n", i); 672 } 673 } 674 675 db_printf("\ndebug register values:\n"); 676 for (i=0; i<8; i++) { 677 db_printf(" dr%d 0x%016lx\n", i, DBREG_DRX((&d), i)); 678 } 679 db_printf("\n"); 680 }
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