1/* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 * 21 * Portions Copyright 2006-2008 John Birrell jb@freebsd.org 22 * 23 */ 24 25/* 26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 27 * Use is subject to license terms. 28 */ 29 30#include <sys/param.h> 31#include <sys/systm.h> 32#include <sys/conf.h> 33#include <sys/cpuvar.h> 34#include <sys/endian.h> 35#include <sys/fcntl.h> 36#include <sys/filio.h> 37#include <sys/kdb.h> 38#include <sys/kernel.h> 39#include <sys/kmem.h> 40#include <sys/kthread.h> 41#include <sys/limits.h> 42#include <sys/linker.h> 43#include <sys/lock.h> 44#include <sys/malloc.h> 45#include <sys/module.h> 46#include <sys/mutex.h> 47#include <sys/pcpu.h> 48#include <sys/poll.h> 49#include <sys/proc.h> 50#include <sys/selinfo.h> 51#include <sys/smp.h> 52#include <sys/syscall.h> 53#include <sys/sysent.h> 54#include <sys/sysproto.h> 55#include <sys/uio.h> 56#include <sys/unistd.h> 57#include <machine/stdarg.h> 58 59#include <sys/dtrace.h> 60#include <sys/dtrace_bsd.h> 61 62#include "fbt.h" 63 64MALLOC_DEFINE(M_FBT, "fbt", "Function Boundary Tracing"); 65 66dtrace_provider_id_t fbt_id; 67fbt_probe_t **fbt_probetab; 68int fbt_probetab_mask; 69 70static int fbt_unload(void); 71static void fbt_getargdesc(void *, dtrace_id_t, void *, dtrace_argdesc_t *); 72static void fbt_provide_module(void *, modctl_t *); 73static void fbt_destroy(void *, dtrace_id_t, void *); 74static void fbt_enable(void *, dtrace_id_t, void *); 75static void fbt_disable(void *, dtrace_id_t, void *); 76static void fbt_load(void *); 77static void fbt_suspend(void *, dtrace_id_t, void *); 78static void fbt_resume(void *, dtrace_id_t, void *); 79 80static dtrace_pattr_t fbt_attr = { 81{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON }, 82{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN }, 83{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA }, 84{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON }, 85{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA }, 86}; 87 88static dtrace_pops_t fbt_pops = { 89 .dtps_provide = NULL, 90 .dtps_provide_module = fbt_provide_module, 91 .dtps_enable = fbt_enable, 92 .dtps_disable = fbt_disable, 93 .dtps_suspend = fbt_suspend, 94 .dtps_resume = fbt_resume, 95 .dtps_getargdesc = fbt_getargdesc, 96 .dtps_getargval = NULL, 97 .dtps_usermode = NULL, 98 .dtps_destroy = fbt_destroy 99}; 100 101static int fbt_probetab_size; 102static int fbt_verbose = 0; 103 104int 105fbt_excluded(const char *name) 106{ 107 108 if (strncmp(name, "dtrace_", 7) == 0 && 109 strncmp(name, "dtrace_safe_", 12) != 0) { 110 /* 111 * Anything beginning with "dtrace_" may be called 112 * from probe context unless it explicitly indicates 113 * that it won't be called from probe context by 114 * using the prefix "dtrace_safe_". 115 */ 116 return (1); 117 } 118 119 /* 120 * Omit instrumentation of functions that are probably in DDB. It 121 * makes it too hard to debug broken FBT. 122 * 123 * NB: kdb_enter() can be excluded, but its call to printf() can't be. 124 * This is generally OK since we're not yet in debugging context. 125 */ 126 if (strncmp(name, "db_", 3) == 0 || 127 strncmp(name, "kdb_", 4) == 0) 128 return (1); 129 130 /* 131 * Lock owner methods may be called from probe context. 132 */ 133 if (strcmp(name, "owner_mtx") == 0 || 134 strcmp(name, "owner_rm") == 0 || 135 strcmp(name, "owner_rw") == 0 || 136 strcmp(name, "owner_sx") == 0) 137 return (1); 138 139 /* 140 * Stack unwinders may be called from probe context on some 141 * platforms. 142 */ 143#if defined(__aarch64__) || defined(__riscv) 144 if (strcmp(name, "unwind_frame") == 0) 145 return (1); 146#endif 147 148 /* 149 * When DTrace is built into the kernel we need to exclude 150 * the FBT functions from instrumentation. 151 */ 152#ifndef _KLD_MODULE 153 if (strncmp(name, "fbt_", 4) == 0) 154 return (1); 155#endif 156 157 return (0); 158} 159 160static void 161fbt_doubletrap(void) 162{ 163 fbt_probe_t *fbt; 164 int i; 165 166 for (i = 0; i < fbt_probetab_size; i++) { 167 fbt = fbt_probetab[i]; 168 169 for (; fbt != NULL; fbt = fbt->fbtp_probenext) 170 fbt_patch_tracepoint(fbt, fbt->fbtp_savedval); 171 } 172} 173 174static void 175fbt_provide_module(void *arg, modctl_t *lf) 176{ 177 char modname[MAXPATHLEN]; 178 int i; 179 size_t len; 180 181 strlcpy(modname, lf->filename, sizeof(modname)); 182 len = strlen(modname); 183 if (len > 3 && strcmp(modname + len - 3, ".ko") == 0) 184 modname[len - 3] = '\0'; 185 186 /* 187 * Employees of dtrace and their families are ineligible. Void 188 * where prohibited. 189 */ 190 if (strcmp(modname, "dtrace") == 0) 191 return; 192 193 /* 194 * To register with DTrace, a module must list 'dtrace' as a 195 * dependency in order for the kernel linker to resolve 196 * symbols like dtrace_register(). All modules with such a 197 * dependency are ineligible for FBT tracing. 198 */ 199 for (i = 0; i < lf->ndeps; i++) 200 if (strncmp(lf->deps[i]->filename, "dtrace", 6) == 0) 201 return; 202 203 if (lf->fbt_nentries) { 204 /* 205 * This module has some FBT entries allocated; we're afraid 206 * to screw with it. 207 */ 208 return; 209 } 210 211 /* 212 * List the functions in the module and the symbol values. 213 */ 214 (void) linker_file_function_listall(lf, fbt_provide_module_function, modname); 215} 216 217static void 218fbt_destroy_one(fbt_probe_t *fbt) 219{ 220 fbt_probe_t *hash, *hashprev, *next; 221 int ndx; 222 223 ndx = FBT_ADDR2NDX(fbt->fbtp_patchpoint); 224 for (hash = fbt_probetab[ndx], hashprev = NULL; hash != NULL; 225 hashprev = hash, hash = hash->fbtp_hashnext) { 226 if (hash == fbt) { 227 if ((next = fbt->fbtp_tracenext) != NULL) 228 next->fbtp_hashnext = hash->fbtp_hashnext; 229 else 230 next = hash->fbtp_hashnext; 231 if (hashprev != NULL) 232 hashprev->fbtp_hashnext = next; 233 else 234 fbt_probetab[ndx] = next; 235 goto free; 236 } else if (hash->fbtp_patchpoint == fbt->fbtp_patchpoint) { 237 for (next = hash; next->fbtp_tracenext != NULL; 238 next = next->fbtp_tracenext) { 239 if (fbt == next->fbtp_tracenext) { 240 next->fbtp_tracenext = 241 fbt->fbtp_tracenext; 242 goto free; 243 } 244 } 245 } 246 } 247 panic("probe %p not found in hash table", fbt); 248free: 249 free(fbt, M_FBT); 250} 251 252static void 253fbt_destroy(void *arg, dtrace_id_t id, void *parg) 254{ 255 fbt_probe_t *fbt = parg, *next; 256 modctl_t *ctl; 257 258 do { 259 ctl = fbt->fbtp_ctl; 260 ctl->fbt_nentries--; 261 262 next = fbt->fbtp_probenext; 263 fbt_destroy_one(fbt); 264 fbt = next; 265 } while (fbt != NULL); 266} 267 268static void 269fbt_enable(void *arg, dtrace_id_t id, void *parg) 270{ 271 fbt_probe_t *fbt = parg; 272 modctl_t *ctl = fbt->fbtp_ctl; 273 274 ctl->nenabled++; 275 276 /* 277 * Now check that our modctl has the expected load count. If it 278 * doesn't, this module must have been unloaded and reloaded -- and 279 * we're not going to touch it. 280 */ 281 if (ctl->loadcnt != fbt->fbtp_loadcnt) { 282 if (fbt_verbose) { 283 printf("fbt is failing for probe %s " 284 "(module %s reloaded)", 285 fbt->fbtp_name, ctl->filename); 286 } 287 288 return; 289 } 290 291 for (; fbt != NULL; fbt = fbt->fbtp_probenext) { 292 fbt_patch_tracepoint(fbt, fbt->fbtp_patchval); 293 fbt->fbtp_enabled++; 294 } 295} 296 297static void 298fbt_disable(void *arg, dtrace_id_t id, void *parg) 299{ 300 fbt_probe_t *fbt = parg, *hash; 301 modctl_t *ctl = fbt->fbtp_ctl; 302 303 ASSERT(ctl->nenabled > 0); 304 ctl->nenabled--; 305 306 if ((ctl->loadcnt != fbt->fbtp_loadcnt)) 307 return; 308 309 for (; fbt != NULL; fbt = fbt->fbtp_probenext) { 310 fbt->fbtp_enabled--; 311 312 for (hash = fbt_probetab[FBT_ADDR2NDX(fbt->fbtp_patchpoint)]; 313 hash != NULL; hash = hash->fbtp_hashnext) { 314 if (hash->fbtp_patchpoint == fbt->fbtp_patchpoint) { 315 for (; hash != NULL; hash = hash->fbtp_tracenext) 316 if (hash->fbtp_enabled > 0) 317 break; 318 break; 319 } 320 } 321 if (hash == NULL) 322 fbt_patch_tracepoint(fbt, fbt->fbtp_savedval); 323 } 324} 325 326static void 327fbt_suspend(void *arg, dtrace_id_t id, void *parg) 328{ 329 fbt_probe_t *fbt = parg; 330 modctl_t *ctl = fbt->fbtp_ctl; 331 332 ASSERT(ctl->nenabled > 0); 333 334 if ((ctl->loadcnt != fbt->fbtp_loadcnt)) 335 return; 336 337 for (; fbt != NULL; fbt = fbt->fbtp_probenext) 338 fbt_patch_tracepoint(fbt, fbt->fbtp_savedval); 339} 340 341static void 342fbt_resume(void *arg, dtrace_id_t id, void *parg) 343{ 344 fbt_probe_t *fbt = parg; 345 modctl_t *ctl = fbt->fbtp_ctl; 346 347 ASSERT(ctl->nenabled > 0); 348 349 if ((ctl->loadcnt != fbt->fbtp_loadcnt)) 350 return; 351 352 for (; fbt != NULL; fbt = fbt->fbtp_probenext) 353 fbt_patch_tracepoint(fbt, fbt->fbtp_patchval); 354} 355 356static int 357fbt_ctfoff_init(modctl_t *lf, linker_ctf_t *lc) 358{ 359 const Elf_Sym *symp = lc->symtab; 360 const ctf_header_t *hp = (const ctf_header_t *) lc->ctftab; 361 const uint8_t *ctfdata = lc->ctftab + sizeof(ctf_header_t); 362 size_t idwidth; 363 int i; 364 uint32_t *ctfoff; 365 uint32_t objtoff = hp->cth_objtoff; 366 uint32_t funcoff = hp->cth_funcoff; 367 uint_t kind, info, vlen; 368 369 /* Sanity check. */ 370 if (hp->cth_magic != CTF_MAGIC) { 371 printf("Bad magic value in CTF data of '%s'\n",lf->pathname); 372 return (EINVAL); 373 } 374 375 if (lc->symtab == NULL) { 376 printf("No symbol table in '%s'\n",lf->pathname); 377 return (EINVAL); 378 } 379 380 ctfoff = malloc(sizeof(uint32_t) * lc->nsym, M_LINKER, M_WAITOK); 381 *lc->ctfoffp = ctfoff; 382 383 idwidth = hp->cth_version == CTF_VERSION_2 ? 2 : 4; 384 385 for (i = 0; i < lc->nsym; i++, ctfoff++, symp++) { 386 if (symp->st_name == 0 || symp->st_shndx == SHN_UNDEF) { 387 *ctfoff = 0xffffffff; 388 continue; 389 } 390 391 switch (ELF_ST_TYPE(symp->st_info)) { 392 case STT_OBJECT: 393 if (objtoff >= hp->cth_funcoff || 394 (symp->st_shndx == SHN_ABS && symp->st_value == 0)) { 395 *ctfoff = 0xffffffff; 396 break; 397 } 398 399 *ctfoff = objtoff; 400 objtoff += idwidth; 401 break; 402 403 case STT_FUNC: 404 if (funcoff >= hp->cth_typeoff) { 405 *ctfoff = 0xffffffff; 406 break; 407 } 408 409 *ctfoff = funcoff; 410 411 info = 0; 412 memcpy(&info, ctfdata + funcoff, idwidth); 413 if (hp->cth_version == CTF_VERSION_2) { 414 kind = CTF_V2_INFO_KIND(info); 415 vlen = CTF_V2_INFO_VLEN(info); 416 } else { 417 kind = CTF_V3_INFO_KIND(info); 418 vlen = CTF_V3_INFO_VLEN(info); 419 } 420 421 /* 422 * If we encounter a zero pad at the end, just skip it. 423 * Otherwise skip over the function and its return type 424 * (+2) and the argument list (vlen). 425 */ 426 if (kind == CTF_K_UNKNOWN && vlen == 0) 427 funcoff += idwidth; 428 else 429 funcoff += idwidth * (vlen + 2); 430 break; 431 432 default: 433 *ctfoff = 0xffffffff; 434 break; 435 } 436 } 437 438 return (0); 439} 440 441static void 442fbt_get_ctt_index(uint8_t version, const void *v, uint_t *indexp, 443 uint_t *typep, int *ischildp) 444{ 445 uint_t index, type; 446 int ischild; 447 448 if (version == CTF_VERSION_2) { 449 const struct ctf_type_v2 *ctt = v; 450 451 type = ctt->ctt_type; 452 index = CTF_V2_TYPE_TO_INDEX(ctt->ctt_type); 453 ischild = CTF_V2_TYPE_ISCHILD(ctt->ctt_type); 454 } else { 455 const struct ctf_type_v3 *ctt = v; 456 457 type = ctt->ctt_type; 458 index = CTF_V3_TYPE_TO_INDEX(ctt->ctt_type); 459 ischild = CTF_V3_TYPE_ISCHILD(ctt->ctt_type); 460 } 461 462 if (indexp != NULL) 463 *indexp = index; 464 if (typep != NULL) 465 *typep = type; 466 if (ischildp != NULL) 467 *ischildp = ischild; 468} 469 470static ssize_t 471fbt_get_ctt_size(uint8_t version, const void *tp, ssize_t *sizep, 472 ssize_t *incrementp) 473{ 474 ssize_t size, increment; 475 476 if (version == CTF_VERSION_2) { 477 const struct ctf_type_v2 *ctt = tp; 478 479 if (ctt->ctt_size == CTF_V2_LSIZE_SENT) { 480 size = CTF_TYPE_LSIZE(ctt); 481 increment = sizeof (struct ctf_type_v2); 482 } else { 483 size = ctt->ctt_size; 484 increment = sizeof (struct ctf_stype_v2); 485 } 486 } else { 487 const struct ctf_type_v3 *ctt = tp; 488 489 if (ctt->ctt_size == CTF_V3_LSIZE_SENT) { 490 size = CTF_TYPE_LSIZE(ctt); 491 increment = sizeof (struct ctf_type_v3); 492 } else { 493 size = ctt->ctt_size; 494 increment = sizeof (struct ctf_stype_v3); 495 } 496 } 497 498 if (sizep) 499 *sizep = size; 500 if (incrementp) 501 *incrementp = increment; 502 503 return (size); 504} 505 506static void 507fbt_get_ctt_info(uint8_t version, const void *tp, uint_t *kindp, uint_t *vlenp, 508 int *isrootp) 509{ 510 uint_t kind, vlen; 511 int isroot; 512 513 if (version == CTF_VERSION_2) { 514 const struct ctf_type_v2 *ctt = tp; 515 516 kind = CTF_V2_INFO_KIND(ctt->ctt_info); 517 vlen = CTF_V2_INFO_VLEN(ctt->ctt_info); 518 isroot = CTF_V2_INFO_ISROOT(ctt->ctt_info); 519 } else { 520 const struct ctf_type_v3 *ctt = tp; 521 522 kind = CTF_V3_INFO_KIND(ctt->ctt_info); 523 vlen = CTF_V3_INFO_VLEN(ctt->ctt_info); 524 isroot = CTF_V3_INFO_ISROOT(ctt->ctt_info); 525 } 526 527 if (kindp != NULL) 528 *kindp = kind; 529 if (vlenp != NULL) 530 *vlenp = vlen; 531 if (isrootp != NULL) 532 *isrootp = isroot; 533} 534 535static int 536fbt_typoff_init(linker_ctf_t *lc) 537{ 538 const ctf_header_t *hp = (const ctf_header_t *) lc->ctftab; 539 const void *tbuf, *tend, *tp; 540 const uint8_t *ctfdata = lc->ctftab + sizeof(ctf_header_t); 541 size_t idwidth; 542 int ctf_typemax = 0; 543 uint32_t *xp; 544 ulong_t pop[CTF_K_MAX + 1] = { 0 }; 545 uint8_t version; 546 547 /* Sanity check. */ 548 if (hp->cth_magic != CTF_MAGIC) 549 return (EINVAL); 550 551 version = hp->cth_version; 552 idwidth = version == CTF_VERSION_2 ? 2 : 4; 553 554 tbuf = (const void *) (ctfdata + hp->cth_typeoff); 555 tend = (const void *) (ctfdata + hp->cth_stroff); 556 557 /* 558 * We make two passes through the entire type section. In this first 559 * pass, we count the number of each type and the total number of types. 560 */ 561 for (tp = tbuf; tp < tend; ctf_typemax++) { 562 uint_t kind, type, vlen; 563 ssize_t size, increment; 564 size_t vbytes; 565 566 (void) fbt_get_ctt_size(version, tp, &size, &increment); 567 fbt_get_ctt_info(version, tp, &kind, &vlen, NULL); 568 fbt_get_ctt_index(version, tp, NULL, &type, NULL); 569 570 switch (kind) { 571 case CTF_K_INTEGER: 572 case CTF_K_FLOAT: 573 vbytes = sizeof (uint_t); 574 break; 575 case CTF_K_ARRAY: 576 if (version == CTF_VERSION_2) 577 vbytes = sizeof (struct ctf_array_v2); 578 else 579 vbytes = sizeof (struct ctf_array_v3); 580 break; 581 case CTF_K_FUNCTION: 582 vbytes = roundup2(idwidth * vlen, sizeof(uint32_t)); 583 break; 584 case CTF_K_STRUCT: 585 case CTF_K_UNION: 586 if (version == CTF_VERSION_2) { 587 if (size < CTF_V2_LSTRUCT_THRESH) 588 vbytes = 589 sizeof (struct ctf_member_v2) * vlen; 590 else 591 vbytes = 592 sizeof (struct ctf_lmember_v2) * vlen; 593 } else { 594 if (size < CTF_V3_LSTRUCT_THRESH) 595 vbytes = 596 sizeof (struct ctf_member_v3) * vlen; 597 else 598 vbytes = 599 sizeof (struct ctf_lmember_v3) * vlen; 600 } 601 break; 602 case CTF_K_ENUM: 603 vbytes = sizeof (ctf_enum_t) * vlen; 604 break; 605 case CTF_K_FORWARD: 606 /* 607 * For forward declarations, ctt_type is the CTF_K_* 608 * kind for the tag, so bump that population count too. 609 * If ctt_type is unknown, treat the tag as a struct. 610 */ 611 if (type == CTF_K_UNKNOWN || type >= CTF_K_MAX) 612 pop[CTF_K_STRUCT]++; 613 else 614 pop[type]++; 615 /*FALLTHRU*/ 616 case CTF_K_UNKNOWN: 617 vbytes = 0; 618 break; 619 case CTF_K_POINTER: 620 case CTF_K_TYPEDEF: 621 case CTF_K_VOLATILE: 622 case CTF_K_CONST: 623 case CTF_K_RESTRICT: 624 vbytes = 0; 625 break; 626 default: 627 printf("%s(%d): detected invalid CTF kind -- %u\n", __func__, __LINE__, kind); 628 return (EIO); 629 } 630 tp = (const void *)((uintptr_t)tp + increment + vbytes); 631 pop[kind]++; 632 } 633 634 /* account for a sentinel value below */ 635 ctf_typemax++; 636 *lc->typlenp = ctf_typemax; 637 638 xp = malloc(sizeof(uint32_t) * ctf_typemax, M_LINKER, 639 M_ZERO | M_WAITOK); 640 641 *lc->typoffp = xp; 642 643 /* type id 0 is used as a sentinel value */ 644 *xp++ = 0; 645 646 /* 647 * In the second pass, fill in the type offset. 648 */ 649 for (tp = tbuf; tp < tend; xp++) { 650 ssize_t size, increment; 651 uint_t kind, vlen; 652 653 size_t vbytes; 654 655 (void) fbt_get_ctt_size(version, tp, &size, &increment); 656 fbt_get_ctt_info(version, tp, &kind, &vlen, NULL); 657 658 switch (kind) { 659 case CTF_K_INTEGER: 660 case CTF_K_FLOAT: 661 vbytes = sizeof (uint_t); 662 break; 663 case CTF_K_ARRAY: 664 if (version == CTF_VERSION_2) 665 vbytes = sizeof (struct ctf_array_v2); 666 else 667 vbytes = sizeof (struct ctf_array_v3); 668 break; 669 case CTF_K_FUNCTION: 670 vbytes = roundup2(idwidth * vlen, sizeof(uint32_t)); 671 break; 672 case CTF_K_STRUCT: 673 case CTF_K_UNION: 674 if (version == CTF_VERSION_2) { 675 if (size < CTF_V2_LSTRUCT_THRESH) 676 vbytes = 677 sizeof (struct ctf_member_v2) * vlen; 678 else 679 vbytes = 680 sizeof (struct ctf_lmember_v2) * vlen; 681 } else { 682 if (size < CTF_V3_LSTRUCT_THRESH) 683 vbytes = 684 sizeof (struct ctf_member_v3) * vlen; 685 else 686 vbytes = 687 sizeof (struct ctf_lmember_v3) * vlen; 688 } 689 break; 690 case CTF_K_ENUM: 691 vbytes = sizeof (ctf_enum_t) * vlen; 692 break; 693 case CTF_K_FORWARD: 694 case CTF_K_UNKNOWN: 695 vbytes = 0; 696 break; 697 case CTF_K_POINTER: 698 case CTF_K_TYPEDEF: 699 case CTF_K_VOLATILE: 700 case CTF_K_CONST: 701 case CTF_K_RESTRICT: 702 vbytes = 0; 703 break; 704 default: 705 printf("%s(%d): detected invalid CTF kind -- %u\n", __func__, __LINE__, kind); 706 return (EIO); 707 } 708 *xp = (uint32_t)((uintptr_t) tp - (uintptr_t) ctfdata); 709 tp = (const void *)((uintptr_t)tp + increment + vbytes); 710 } 711 712 return (0); 713} 714 715/* 716 * CTF Declaration Stack 717 * 718 * In order to implement ctf_type_name(), we must convert a type graph back 719 * into a C type declaration. Unfortunately, a type graph represents a storage 720 * class ordering of the type whereas a type declaration must obey the C rules 721 * for operator precedence, and the two orderings are frequently in conflict. 722 * For example, consider these CTF type graphs and their C declarations: 723 * 724 * CTF_K_POINTER -> CTF_K_FUNCTION -> CTF_K_INTEGER : int (*)() 725 * CTF_K_POINTER -> CTF_K_ARRAY -> CTF_K_INTEGER : int (*)[] 726 * 727 * In each case, parentheses are used to raise operator * to higher lexical 728 * precedence, so the string form of the C declaration cannot be constructed by 729 * walking the type graph links and forming the string from left to right. 730 * 731 * The functions in this file build a set of stacks from the type graph nodes 732 * corresponding to the C operator precedence levels in the appropriate order. 733 * The code in ctf_type_name() can then iterate over the levels and nodes in 734 * lexical precedence order and construct the final C declaration string. 735 */ 736typedef struct ctf_list { 737 struct ctf_list *l_prev; /* previous pointer or tail pointer */ 738 struct ctf_list *l_next; /* next pointer or head pointer */ 739} ctf_list_t; 740 741#define ctf_list_prev(elem) ((void *)(((ctf_list_t *)(elem))->l_prev)) 742#define ctf_list_next(elem) ((void *)(((ctf_list_t *)(elem))->l_next)) 743 744typedef enum { 745 CTF_PREC_BASE, 746 CTF_PREC_POINTER, 747 CTF_PREC_ARRAY, 748 CTF_PREC_FUNCTION, 749 CTF_PREC_MAX 750} ctf_decl_prec_t; 751 752typedef struct ctf_decl_node { 753 ctf_list_t cd_list; /* linked list pointers */ 754 ctf_id_t cd_type; /* type identifier */ 755 uint_t cd_kind; /* type kind */ 756 uint_t cd_n; /* type dimension if array */ 757} ctf_decl_node_t; 758 759typedef struct ctf_decl { 760 ctf_list_t cd_nodes[CTF_PREC_MAX]; /* declaration node stacks */ 761 int cd_order[CTF_PREC_MAX]; /* storage order of decls */ 762 ctf_decl_prec_t cd_qualp; /* qualifier precision */ 763 ctf_decl_prec_t cd_ordp; /* ordered precision */ 764 char *cd_buf; /* buffer for output */ 765 char *cd_ptr; /* buffer location */ 766 char *cd_end; /* buffer limit */ 767 size_t cd_len; /* buffer space required */ 768 int cd_err; /* saved error value */ 769} ctf_decl_t; 770 771/* 772 * Simple doubly-linked list append routine. This implementation assumes that 773 * each list element contains an embedded ctf_list_t as the first member. 774 * An additional ctf_list_t is used to store the head (l_next) and tail 775 * (l_prev) pointers. The current head and tail list elements have their 776 * previous and next pointers set to NULL, respectively. 777 */ 778static void 779ctf_list_append(ctf_list_t *lp, void *new) 780{ 781 ctf_list_t *p = lp->l_prev; /* p = tail list element */ 782 ctf_list_t *q = new; /* q = new list element */ 783 784 lp->l_prev = q; 785 q->l_prev = p; 786 q->l_next = NULL; 787 788 if (p != NULL) 789 p->l_next = q; 790 else 791 lp->l_next = q; 792} 793 794/* 795 * Prepend the specified existing element to the given ctf_list_t. The 796 * existing pointer should be pointing at a struct with embedded ctf_list_t. 797 */ 798static void 799ctf_list_prepend(ctf_list_t *lp, void *new) 800{ 801 ctf_list_t *p = new; /* p = new list element */ 802 ctf_list_t *q = lp->l_next; /* q = head list element */ 803 804 lp->l_next = p; 805 p->l_prev = NULL; 806 p->l_next = q; 807 808 if (q != NULL) 809 q->l_prev = p; 810 else 811 lp->l_prev = p; 812} 813 814static void 815ctf_decl_init(ctf_decl_t *cd, char *buf, size_t len) 816{ 817 int i; 818 819 bzero(cd, sizeof (ctf_decl_t)); 820 821 for (i = CTF_PREC_BASE; i < CTF_PREC_MAX; i++) 822 cd->cd_order[i] = CTF_PREC_BASE - 1; 823 824 cd->cd_qualp = CTF_PREC_BASE; 825 cd->cd_ordp = CTF_PREC_BASE; 826 827 cd->cd_buf = buf; 828 cd->cd_ptr = buf; 829 cd->cd_end = buf + len; 830} 831 832static void 833ctf_decl_fini(ctf_decl_t *cd) 834{ 835 ctf_decl_node_t *cdp, *ndp; 836 int i; 837 838 for (i = CTF_PREC_BASE; i < CTF_PREC_MAX; i++) { 839 for (cdp = ctf_list_next(&cd->cd_nodes[i]); 840 cdp != NULL; cdp = ndp) { 841 ndp = ctf_list_next(cdp); 842 free(cdp, M_FBT); 843 } 844 } 845} 846 847static const void * 848ctf_lookup_by_id(linker_ctf_t *lc, ctf_id_t type) 849{ 850 const void *tp; 851 uint32_t offset; 852 uint32_t *typoff = *lc->typoffp; 853 854 if (type >= *lc->typlenp) { 855 printf("%s(%d): type %d exceeds max %ld\n",__func__,__LINE__,(int) type,*lc->typlenp); 856 return(NULL); 857 } 858 859 /* Check if the type isn't cross-referenced. */ 860 if ((offset = typoff[type]) == 0) { 861 printf("%s(%d): type %d isn't cross referenced\n",__func__,__LINE__, (int) type); 862 return(NULL); 863 } 864 865 tp = (const void *) (lc->ctftab + offset + sizeof(ctf_header_t)); 866 867 return (tp); 868} 869 870static void 871fbt_array_info(linker_ctf_t *lc, ctf_id_t type, ctf_arinfo_t *arp) 872{ 873 const ctf_header_t *hp = (const ctf_header_t *) lc->ctftab; 874 const void *tp; 875 ssize_t increment; 876 uint_t kind; 877 878 bzero(arp, sizeof(*arp)); 879 880 if ((tp = ctf_lookup_by_id(lc, type)) == NULL) 881 return; 882 883 fbt_get_ctt_info(hp->cth_version, tp, &kind, NULL, NULL); 884 if (kind != CTF_K_ARRAY) 885 return; 886 887 (void) fbt_get_ctt_size(hp->cth_version, tp, NULL, &increment); 888 889 if (hp->cth_version == CTF_VERSION_2) { 890 const struct ctf_array_v2 *ap; 891 892 ap = (const struct ctf_array_v2 *)((uintptr_t)tp + increment); 893 arp->ctr_contents = ap->cta_contents; 894 arp->ctr_index = ap->cta_index; 895 arp->ctr_nelems = ap->cta_nelems; 896 } else { 897 const struct ctf_array_v3 *ap; 898 899 ap = (const struct ctf_array_v3 *)((uintptr_t)tp + increment); 900 arp->ctr_contents = ap->cta_contents; 901 arp->ctr_index = ap->cta_index; 902 arp->ctr_nelems = ap->cta_nelems; 903 } 904} 905 906static const char * 907ctf_strptr(linker_ctf_t *lc, int name) 908{ 909 const ctf_header_t *hp = (const ctf_header_t *) lc->ctftab; 910 const char *strp = ""; 911 912 if (name < 0 || name >= hp->cth_strlen) 913 return(strp); 914 915 strp = (const char *)(lc->ctftab + hp->cth_stroff + name + sizeof(ctf_header_t)); 916 917 return (strp); 918} 919 920static const char * 921ctf_type_rname(linker_ctf_t *lc, const void *v) 922{ 923 const ctf_header_t *hp = (const ctf_header_t *) lc->ctftab; 924 uint_t name; 925 926 if (hp->cth_version == CTF_VERSION_2) { 927 const struct ctf_type_v2 *ctt = v; 928 929 name = ctt->ctt_name; 930 } else { 931 const struct ctf_type_v3 *ctt = v; 932 933 name = ctt->ctt_name; 934 } 935 936 return (ctf_strptr(lc, name)); 937} 938 939static void 940ctf_decl_push(ctf_decl_t *cd, linker_ctf_t *lc, ctf_id_t type) 941{ 942 const ctf_header_t *hp = (const ctf_header_t *) lc->ctftab; 943 ctf_decl_node_t *cdp; 944 ctf_decl_prec_t prec; 945 uint_t kind, n = 1, t; 946 int is_qual = 0; 947 948 const void *tp; 949 ctf_arinfo_t ar; 950 951 if ((tp = ctf_lookup_by_id(lc, type)) == NULL) { 952 cd->cd_err = ENOENT; 953 return; 954 } 955 956 fbt_get_ctt_info(hp->cth_version, tp, &kind, NULL, NULL); 957 fbt_get_ctt_index(hp->cth_version, tp, NULL, &t, NULL); 958 959 switch (kind) { 960 case CTF_K_ARRAY: 961 fbt_array_info(lc, type, &ar); 962 ctf_decl_push(cd, lc, ar.ctr_contents); 963 n = ar.ctr_nelems; 964 prec = CTF_PREC_ARRAY; 965 break; 966 967 case CTF_K_TYPEDEF: 968 if (ctf_type_rname(lc, tp)[0] == '\0') { 969 ctf_decl_push(cd, lc, t); 970 return; 971 } 972 prec = CTF_PREC_BASE; 973 break; 974 975 case CTF_K_FUNCTION: 976 ctf_decl_push(cd, lc, t); 977 prec = CTF_PREC_FUNCTION; 978 break; 979 980 case CTF_K_POINTER: 981 ctf_decl_push(cd, lc, t); 982 prec = CTF_PREC_POINTER; 983 break; 984 985 case CTF_K_VOLATILE: 986 case CTF_K_CONST: 987 case CTF_K_RESTRICT: 988 ctf_decl_push(cd, lc, t); 989 prec = cd->cd_qualp; 990 is_qual++; 991 break; 992 993 default: 994 prec = CTF_PREC_BASE; 995 } 996 997 cdp = malloc(sizeof(*cdp), M_FBT, M_WAITOK); 998 cdp->cd_type = type; 999 cdp->cd_kind = kind; 1000 cdp->cd_n = n; 1001 1002 if (ctf_list_next(&cd->cd_nodes[prec]) == NULL) 1003 cd->cd_order[prec] = cd->cd_ordp++; 1004 1005 /* 1006 * Reset cd_qualp to the highest precedence level that we've seen so 1007 * far that can be qualified (CTF_PREC_BASE or CTF_PREC_POINTER). 1008 */ 1009 if (prec > cd->cd_qualp && prec < CTF_PREC_ARRAY) 1010 cd->cd_qualp = prec; 1011 1012 /* 1013 * C array declarators are ordered inside out so prepend them. Also by 1014 * convention qualifiers of base types precede the type specifier (e.g. 1015 * const int vs. int const) even though the two forms are equivalent. 1016 */ 1017 if (kind == CTF_K_ARRAY || (is_qual && prec == CTF_PREC_BASE)) 1018 ctf_list_prepend(&cd->cd_nodes[prec], cdp); 1019 else 1020 ctf_list_append(&cd->cd_nodes[prec], cdp); 1021} 1022 1023static void 1024ctf_decl_sprintf(ctf_decl_t *cd, const char *format, ...) 1025{ 1026 size_t len = (size_t)(cd->cd_end - cd->cd_ptr); 1027 va_list ap; 1028 size_t n; 1029 1030 va_start(ap, format); 1031 n = vsnprintf(cd->cd_ptr, len, format, ap); 1032 va_end(ap); 1033 1034 cd->cd_ptr += MIN(n, len); 1035 cd->cd_len += n; 1036} 1037 1038static ssize_t 1039fbt_type_name(linker_ctf_t *lc, ctf_id_t type, char *buf, size_t len) 1040{ 1041 ctf_decl_t cd; 1042 ctf_decl_node_t *cdp; 1043 ctf_decl_prec_t prec, lp, rp; 1044 int ptr, arr; 1045 uint_t k; 1046 1047 if (lc == NULL && type == CTF_ERR) 1048 return (-1); /* simplify caller code by permitting CTF_ERR */ 1049 1050 ctf_decl_init(&cd, buf, len); 1051 ctf_decl_push(&cd, lc, type); 1052 1053 if (cd.cd_err != 0) { 1054 ctf_decl_fini(&cd); 1055 return (-1); 1056 } 1057 1058 /* 1059 * If the type graph's order conflicts with lexical precedence order 1060 * for pointers or arrays, then we need to surround the declarations at 1061 * the corresponding lexical precedence with parentheses. This can 1062 * result in either a parenthesized pointer (*) as in int (*)() or 1063 * int (*)[], or in a parenthesized pointer and array as in int (*[])(). 1064 */ 1065 ptr = cd.cd_order[CTF_PREC_POINTER] > CTF_PREC_POINTER; 1066 arr = cd.cd_order[CTF_PREC_ARRAY] > CTF_PREC_ARRAY; 1067 1068 rp = arr ? CTF_PREC_ARRAY : ptr ? CTF_PREC_POINTER : -1; 1069 lp = ptr ? CTF_PREC_POINTER : arr ? CTF_PREC_ARRAY : -1; 1070 1071 k = CTF_K_POINTER; /* avoid leading whitespace (see below) */ 1072 1073 for (prec = CTF_PREC_BASE; prec < CTF_PREC_MAX; prec++) { 1074 for (cdp = ctf_list_next(&cd.cd_nodes[prec]); 1075 cdp != NULL; cdp = ctf_list_next(cdp)) { 1076 1077 const void *tp = ctf_lookup_by_id(lc, cdp->cd_type); 1078 const char *name = ctf_type_rname(lc, tp); 1079 1080 if (k != CTF_K_POINTER && k != CTF_K_ARRAY) 1081 ctf_decl_sprintf(&cd, " "); 1082 1083 if (lp == prec) { 1084 ctf_decl_sprintf(&cd, "("); 1085 lp = -1; 1086 } 1087 1088 switch (cdp->cd_kind) { 1089 case CTF_K_INTEGER: 1090 case CTF_K_FLOAT: 1091 case CTF_K_TYPEDEF: 1092 ctf_decl_sprintf(&cd, "%s", name); 1093 break; 1094 case CTF_K_POINTER: 1095 ctf_decl_sprintf(&cd, "*"); 1096 break; 1097 case CTF_K_ARRAY: 1098 ctf_decl_sprintf(&cd, "[%u]", cdp->cd_n); 1099 break; 1100 case CTF_K_FUNCTION: 1101 ctf_decl_sprintf(&cd, "()"); 1102 break; 1103 case CTF_K_STRUCT: 1104 case CTF_K_FORWARD: 1105 ctf_decl_sprintf(&cd, "struct %s", name); 1106 break; 1107 case CTF_K_UNION: 1108 ctf_decl_sprintf(&cd, "union %s", name); 1109 break; 1110 case CTF_K_ENUM: 1111 ctf_decl_sprintf(&cd, "enum %s", name); 1112 break; 1113 case CTF_K_VOLATILE: 1114 ctf_decl_sprintf(&cd, "volatile"); 1115 break; 1116 case CTF_K_CONST: 1117 ctf_decl_sprintf(&cd, "const"); 1118 break; 1119 case CTF_K_RESTRICT: 1120 ctf_decl_sprintf(&cd, "restrict"); 1121 break; 1122 } 1123 1124 k = cdp->cd_kind; 1125 } 1126 1127 if (rp == prec) 1128 ctf_decl_sprintf(&cd, ")"); 1129 } 1130 1131 ctf_decl_fini(&cd); 1132 return (cd.cd_len); 1133} 1134 1135static void 1136fbt_getargdesc(void *arg __unused, dtrace_id_t id __unused, void *parg, dtrace_argdesc_t *desc) 1137{ 1138 const ctf_header_t *hp; 1139 const char *dp; 1140 fbt_probe_t *fbt = parg; 1141 linker_ctf_t lc; 1142 modctl_t *ctl = fbt->fbtp_ctl; 1143 size_t idwidth; 1144 int ndx = desc->dtargd_ndx; 1145 int symindx = fbt->fbtp_symindx; 1146 uint32_t *ctfoff; 1147 uint32_t offset, type; 1148 uint_t info, n; 1149 ushort_t kind; 1150 1151 if (fbt->fbtp_roffset != 0 && desc->dtargd_ndx == 0) { 1152 (void) strcpy(desc->dtargd_native, "int"); 1153 return; 1154 } 1155 1156 desc->dtargd_ndx = DTRACE_ARGNONE; 1157 1158 /* Get a pointer to the CTF data and it's length. */ 1159 if (linker_ctf_get(ctl, &lc) != 0) 1160 /* No CTF data? Something wrong? *shrug* */ 1161 return; 1162 1163 /* Check if this module hasn't been initialised yet. */ 1164 if (*lc.ctfoffp == NULL) { 1165 /* 1166 * Initialise the CTF object and function symindx to 1167 * byte offset array. 1168 */ 1169 if (fbt_ctfoff_init(ctl, &lc) != 0) 1170 return; 1171 1172 /* Initialise the CTF type to byte offset array. */ 1173 if (fbt_typoff_init(&lc) != 0) 1174 return; 1175 } 1176 1177 ctfoff = *lc.ctfoffp; 1178 1179 if (ctfoff == NULL || *lc.typoffp == NULL) 1180 return; 1181 1182 /* Check if the symbol index is out of range. */ 1183 if (symindx >= lc.nsym) 1184 return; 1185 1186 /* Check if the symbol isn't cross-referenced. */ 1187 if ((offset = ctfoff[symindx]) == 0xffffffff) 1188 return; 1189 1190 hp = (const ctf_header_t *) lc.ctftab; 1191 idwidth = hp->cth_version == CTF_VERSION_2 ? 2 : 4; 1192 dp = (const char *)(lc.ctftab + offset + sizeof(ctf_header_t)); 1193 1194 info = 0; 1195 memcpy(&info, dp, idwidth); 1196 dp += idwidth; 1197 if (hp->cth_version == CTF_VERSION_2) { 1198 kind = CTF_V2_INFO_KIND(info); 1199 n = CTF_V2_INFO_VLEN(info); 1200 } else { 1201 kind = CTF_V3_INFO_KIND(info); 1202 n = CTF_V3_INFO_VLEN(info); 1203 } 1204 1205 if (kind == CTF_K_UNKNOWN && n == 0) { 1206 printf("%s(%d): Unknown function!\n",__func__,__LINE__); 1207 return; 1208 } 1209 1210 if (kind != CTF_K_FUNCTION) { 1211 printf("%s(%d): Expected a function!\n",__func__,__LINE__); 1212 return; 1213 } 1214 1215 if (fbt->fbtp_roffset != 0) { 1216 /* Only return type is available for args[1] in return probe. */ 1217 if (ndx > 1) 1218 return; 1219 ASSERT(ndx == 1); 1220 } else { 1221 /* Check if the requested argument doesn't exist. */ 1222 if (ndx >= n) 1223 return; 1224 1225 /* Skip the return type and arguments up to the one requested. */ 1226 dp += idwidth * (ndx + 1); 1227 } 1228 1229 type = 0; 1230 memcpy(&type, dp, idwidth); 1231 if (fbt_type_name(&lc, type, desc->dtargd_native, sizeof(desc->dtargd_native)) > 0) 1232 desc->dtargd_ndx = ndx; 1233} 1234 1235static int 1236fbt_linker_file_cb(linker_file_t lf, void *arg) 1237{ 1238 1239 fbt_provide_module(arg, lf); 1240 1241 return (0); 1242} 1243 1244static void 1245fbt_load(void *dummy) 1246{ 1247 /* Default the probe table size if not specified. */ 1248 if (fbt_probetab_size == 0) 1249 fbt_probetab_size = FBT_PROBETAB_SIZE; 1250 1251 /* Choose the hash mask for the probe table. */ 1252 fbt_probetab_mask = fbt_probetab_size - 1; 1253 1254 /* Allocate memory for the probe table. */ 1255 fbt_probetab = 1256 malloc(fbt_probetab_size * sizeof (fbt_probe_t *), M_FBT, M_WAITOK | M_ZERO); 1257 1258 dtrace_doubletrap_func = fbt_doubletrap; 1259 dtrace_invop_add(fbt_invop); 1260 1261 if (dtrace_register("fbt", &fbt_attr, DTRACE_PRIV_USER, 1262 NULL, &fbt_pops, NULL, &fbt_id) != 0) 1263 return; 1264 1265 /* Create probes for the kernel and already-loaded modules. */ 1266 linker_file_foreach(fbt_linker_file_cb, NULL); 1267} 1268 1269static int 1270fbt_unload(void) 1271{ 1272 int error = 0; 1273 1274 /* De-register the invalid opcode handler. */ 1275 dtrace_invop_remove(fbt_invop); 1276 1277 dtrace_doubletrap_func = NULL; 1278 1279 /* De-register this DTrace provider. */ 1280 if ((error = dtrace_unregister(fbt_id)) != 0) 1281 return (error); 1282 1283 /* Free the probe table. */ 1284 free(fbt_probetab, M_FBT); 1285 fbt_probetab = NULL; 1286 fbt_probetab_mask = 0; 1287 1288 return (error); 1289} 1290 1291static int 1292fbt_modevent(module_t mod __unused, int type, void *data __unused) 1293{ 1294 int error = 0; 1295 1296 switch (type) { 1297 case MOD_LOAD: 1298 break; 1299 1300 case MOD_UNLOAD: 1301 break; 1302 1303 case MOD_SHUTDOWN: 1304 break; 1305 1306 default: 1307 error = EOPNOTSUPP; 1308 break; 1309 1310 } 1311 1312 return (error); 1313} 1314 1315SYSINIT(fbt_load, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, fbt_load, NULL); 1316SYSUNINIT(fbt_unload, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, fbt_unload, NULL); 1317 1318DEV_MODULE(fbt, fbt_modevent, NULL); 1319MODULE_VERSION(fbt, 1); 1320MODULE_DEPEND(fbt, dtrace, 1, 1, 1); 1321MODULE_DEPEND(fbt, opensolaris, 1, 1, 1); 1322