1 /* SPDX-License-Identifier: GPL-2.0-only */ 1 2 /* 3 * recordmcount.h 4 * 5 * This code was taken out of recordmcount.c w 6 * Copyright 2009 John F. Reiser <jreiser@BitW 7 * 8 * The original code had the same algorithms f 9 * and 64bit ELF files, but the code was dupli 10 * the difference in structures that were used 11 * file creates a macro of everything that is 12 * the 64 and 32 bit code, such that by includ 13 * twice we can create both sets of functions 14 * header once with RECORD_MCOUNT_64 undefined 15 * it defined. 16 * 17 * This conversion to macros was done by: 18 * Copyright 2010 Steven Rostedt <srostedt@red 19 */ 20 #undef append_func 21 #undef is_fake_mcount 22 #undef fn_is_fake_mcount 23 #undef MIPS_is_fake_mcount 24 #undef mcount_adjust 25 #undef sift_rel_mcount 26 #undef nop_mcount 27 #undef find_secsym_ndx 28 #undef __has_rel_mcount 29 #undef has_rel_mcount 30 #undef tot_relsize 31 #undef get_mcountsym 32 #undef find_symtab 33 #undef get_shnum 34 #undef set_shnum 35 #undef get_shstrndx 36 #undef get_symindex 37 #undef get_sym_str_and_relp 38 #undef do_func 39 #undef Elf_Addr 40 #undef Elf_Ehdr 41 #undef Elf_Shdr 42 #undef Elf_Rel 43 #undef Elf_Rela 44 #undef Elf_Sym 45 #undef ELF_R_SYM 46 #undef Elf_r_sym 47 #undef ELF_R_INFO 48 #undef Elf_r_info 49 #undef ELF_ST_BIND 50 #undef ELF_ST_TYPE 51 #undef fn_ELF_R_SYM 52 #undef fn_ELF_R_INFO 53 #undef uint_t 54 #undef _w 55 #undef _align 56 #undef _size 57 58 #ifdef RECORD_MCOUNT_64 59 # define append_func append64 60 # define sift_rel_mcount sift64_rel_mco 61 # define nop_mcount nop_mcount_64 62 # define find_secsym_ndx find64_secsym_ 63 # define __has_rel_mcount __has64_rel_mc 64 # define has_rel_mcount has64_rel_mcou 65 # define tot_relsize tot64_relsize 66 # define find_symtab find_symtab64 67 # define get_shnum get_shnum64 68 # define set_shnum set_shnum64 69 # define get_shstrndx get_shstrndx64 70 # define get_symindex get_symindex64 71 # define get_sym_str_and_relp get_sym_str_an 72 # define do_func do64 73 # define get_mcountsym get_mcountsym_ 74 # define is_fake_mcount is_fake_mcount 75 # define fn_is_fake_mcount fn_is_fake_mco 76 # define MIPS_is_fake_mcount MIPS64_is_fake 77 # define mcount_adjust mcount_adjust_ 78 # define Elf_Addr Elf64_Addr 79 # define Elf_Ehdr Elf64_Ehdr 80 # define Elf_Shdr Elf64_Shdr 81 # define Elf_Rel Elf64_Rel 82 # define Elf_Rela Elf64_Rela 83 # define Elf_Sym Elf64_Sym 84 # define ELF_R_SYM ELF64_R_SYM 85 # define Elf_r_sym Elf64_r_sym 86 # define ELF_R_INFO ELF64_R_INFO 87 # define Elf_r_info Elf64_r_info 88 # define ELF_ST_BIND ELF64_ST_BIND 89 # define ELF_ST_TYPE ELF64_ST_TYPE 90 # define fn_ELF_R_SYM fn_ELF64_R_SYM 91 # define fn_ELF_R_INFO fn_ELF64_R_INF 92 # define uint_t uint64_t 93 # define _w w8 94 # define _align 7u 95 # define _size 8 96 #else 97 # define append_func append32 98 # define sift_rel_mcount sift32_rel_mco 99 # define nop_mcount nop_mcount_32 100 # define find_secsym_ndx find32_secsym_ 101 # define __has_rel_mcount __has32_rel_mc 102 # define has_rel_mcount has32_rel_mcou 103 # define tot_relsize tot32_relsize 104 # define find_symtab find_symtab32 105 # define get_shnum get_shnum32 106 # define set_shnum set_shnum32 107 # define get_shstrndx get_shstrndx32 108 # define get_symindex get_symindex32 109 # define get_sym_str_and_relp get_sym_str_an 110 # define do_func do32 111 # define get_mcountsym get_mcountsym_ 112 # define is_fake_mcount is_fake_mcount 113 # define fn_is_fake_mcount fn_is_fake_mco 114 # define MIPS_is_fake_mcount MIPS32_is_fake 115 # define mcount_adjust mcount_adjust_ 116 # define Elf_Addr Elf32_Addr 117 # define Elf_Ehdr Elf32_Ehdr 118 # define Elf_Shdr Elf32_Shdr 119 # define Elf_Rel Elf32_Rel 120 # define Elf_Rela Elf32_Rela 121 # define Elf_Sym Elf32_Sym 122 # define ELF_R_SYM ELF32_R_SYM 123 # define Elf_r_sym Elf32_r_sym 124 # define ELF_R_INFO ELF32_R_INFO 125 # define Elf_r_info Elf32_r_info 126 # define ELF_ST_BIND ELF32_ST_BIND 127 # define ELF_ST_TYPE ELF32_ST_TYPE 128 # define fn_ELF_R_SYM fn_ELF32_R_SYM 129 # define fn_ELF_R_INFO fn_ELF32_R_INF 130 # define uint_t uint32_t 131 # define _w w 132 # define _align 3u 133 # define _size 4 134 #endif 135 136 /* Functions and pointers that do_file() may o 137 static int fn_is_fake_mcount(Elf_Rel const *rp 138 { 139 return 0; 140 } 141 static int (*is_fake_mcount)(Elf_Rel const *rp 142 143 static uint_t fn_ELF_R_SYM(Elf_Rel const *rp) 144 { 145 return ELF_R_SYM(_w(rp->r_info)); 146 } 147 static uint_t (*Elf_r_sym)(Elf_Rel const *rp) 148 149 static void fn_ELF_R_INFO(Elf_Rel *const rp, u 150 { 151 rp->r_info = _w(ELF_R_INFO(sym, type)) 152 } 153 static void (*Elf_r_info)(Elf_Rel *const rp, u 154 155 static int mcount_adjust = 0; 156 157 /* 158 * MIPS mcount long call has 2 _mcount symbols 159 * _mcount symbol is needed for dynamic functi 160 * tracing(ftrace_make_nop), the instruction i 161 * the "b label" instruction, to enable tracin 162 * instruction back. So, here, we set the 2nd 163 * 164 * c: 3c030000 lui v1,0x0 165 * c: R_MIPS_HI16 _mcount 166 * c: R_MIPS_NONE *ABS* 167 * c: R_MIPS_NONE *ABS* 168 * 10: 64630000 daddiu v1,v1,0 169 * 10: R_MIPS_LO16 _mcount 170 * 10: R_MIPS_NONE *ABS* 171 * 10: R_MIPS_NONE *ABS* 172 * 14: 03e0082d move at,ra 173 * 18: 0060f809 jalr v1 174 * label: 175 */ 176 #define MIPS_FAKEMCOUNT_OFFSET 4 177 178 static int MIPS_is_fake_mcount(Elf_Rel const * 179 { 180 static Elf_Addr old_r_offset = ~(Elf_A 181 Elf_Addr current_r_offset = _w(rp->r_o 182 int is_fake; 183 184 is_fake = (old_r_offset != ~(Elf_Addr) 185 (current_r_offset - old_r_offs 186 old_r_offset = current_r_offset; 187 188 return is_fake; 189 } 190 191 static unsigned int get_symindex(Elf_Sym const 192 Elf32_Word co 193 { 194 unsigned long offset; 195 unsigned short shndx = w2(sym->st_shnd 196 int index; 197 198 if (shndx > SHN_UNDEF && shndx < SHN_L 199 return shndx; 200 201 if (shndx == SHN_XINDEX) { 202 offset = (unsigned long)sym - 203 index = offset / sizeof(*sym); 204 205 return w(symtab_shndx[index]); 206 } 207 208 return 0; 209 } 210 211 static unsigned int get_shnum(Elf_Ehdr const * 212 { 213 if (shdr0 && !ehdr->e_shnum) 214 return w(shdr0->sh_size); 215 216 return w2(ehdr->e_shnum); 217 } 218 219 static void set_shnum(Elf_Ehdr *ehdr, Elf_Shdr 220 { 221 if (new_shnum >= SHN_LORESERVE) { 222 ehdr->e_shnum = 0; 223 shdr0->sh_size = w(new_shnum); 224 } else 225 ehdr->e_shnum = w2(new_shnum); 226 } 227 228 static int get_shstrndx(Elf_Ehdr const *ehdr, 229 { 230 if (ehdr->e_shstrndx != SHN_XINDEX) 231 return w2(ehdr->e_shstrndx); 232 233 return w(shdr0->sh_link); 234 } 235 236 static void find_symtab(Elf_Ehdr *const ehdr, 237 unsigned const nhdr, E 238 Elf32_Word **symtab_sh 239 { 240 Elf_Shdr const *relhdr; 241 unsigned k; 242 243 *symtab = NULL; 244 *symtab_shndx = NULL; 245 246 for (relhdr = shdr0, k = nhdr; k; --k, 247 if (relhdr->sh_type == SHT_SYM 248 *symtab = (void *)ehdr 249 else if (relhdr->sh_type == SH 250 *symtab_shndx = (void 251 252 if (*symtab && *symtab_shndx) 253 break; 254 } 255 } 256 257 /* Append the new shstrtab, Elf_Shdr[], __mcou 258 static int append_func(Elf_Ehdr *const ehdr, 259 Elf_Shdr *const shstr, 260 uint_t const *const ml 261 uint_t const *const ml 262 Elf_Rel const *const m 263 Elf_Rel const *const m 264 unsigned int const rel 265 unsigned int const sym 266 { 267 /* Begin constructing output file */ 268 Elf_Shdr mcsec; 269 char const *mc_name = (sizeof(Elf_Rela 270 ? ".rela__mcount_loc" 271 : ".rel__mcount_loc"; 272 uint_t const old_shoff = _w(ehdr->e_sh 273 uint_t const old_shstr_sh_size = _w( 274 uint_t const old_shstr_sh_offset = _w( 275 Elf_Shdr *const shdr0 = (Elf_Shdr *)(o 276 unsigned int const old_shnum = get_shn 277 unsigned int const new_shnum = 2 + old 278 uint_t t = 1 + strlen(mc_name) + _w(sh 279 uint_t new_e_shoff; 280 281 shstr->sh_size = _w(t); 282 shstr->sh_offset = _w(sb.st_size); 283 t += sb.st_size; 284 t += (_align & -t); /* word-byte alig 285 new_e_shoff = t; 286 287 set_shnum(ehdr, shdr0, new_shnum); 288 289 /* body for new shstrtab */ 290 if (ulseek(sb.st_size, SEEK_SET) < 0) 291 return -1; 292 if (uwrite(old_shstr_sh_offset + (void 293 return -1; 294 if (uwrite(mc_name, 1 + strlen(mc_name 295 return -1; 296 297 /* old(modified) Elf_Shdr table, word- 298 if (ulseek(t, SEEK_SET) < 0) 299 return -1; 300 t += sizeof(Elf_Shdr) * old_shnum; 301 if (uwrite(old_shoff + (void *)ehdr, 302 sizeof(Elf_Shdr) * old_shnum) < 303 return -1; 304 305 /* new sections __mcount_loc and .rel_ 306 t += 2*sizeof(mcsec); 307 mcsec.sh_name = w((sizeof(Elf_Rela) == 308 + old_shstr_sh_size); 309 mcsec.sh_type = w(SHT_PROGBITS); 310 mcsec.sh_flags = _w(SHF_ALLOC); 311 mcsec.sh_addr = 0; 312 mcsec.sh_offset = _w(t); 313 mcsec.sh_size = _w((void *)mlocp - (vo 314 mcsec.sh_link = 0; 315 mcsec.sh_info = 0; 316 mcsec.sh_addralign = _w(_size); 317 mcsec.sh_entsize = _w(_size); 318 if (uwrite(&mcsec, sizeof(mcsec)) < 0) 319 return -1; 320 321 mcsec.sh_name = w(old_shstr_sh_size); 322 mcsec.sh_type = (sizeof(Elf_Rela) == r 323 ? w(SHT_RELA) 324 : w(SHT_REL); 325 mcsec.sh_flags = 0; 326 mcsec.sh_addr = 0; 327 mcsec.sh_offset = _w((void *)mlocp - ( 328 mcsec.sh_size = _w((void *)mrelp - ( 329 mcsec.sh_link = w(symsec_sh_link); 330 mcsec.sh_info = w(old_shnum); 331 mcsec.sh_addralign = _w(_size); 332 mcsec.sh_entsize = _w(rel_entsize); 333 334 if (uwrite(&mcsec, sizeof(mcsec)) < 0) 335 return -1; 336 337 if (uwrite(mloc0, (void *)mlocp - (voi 338 return -1; 339 if (uwrite(mrel0, (void *)mrelp - (voi 340 return -1; 341 342 ehdr->e_shoff = _w(new_e_shoff); 343 if (ulseek(0, SEEK_SET) < 0) 344 return -1; 345 if (uwrite(ehdr, sizeof(*ehdr)) < 0) 346 return -1; 347 return 0; 348 } 349 350 static unsigned get_mcountsym(Elf_Sym const *c 351 Elf_Rel const *r 352 char const *cons 353 { 354 unsigned mcountsym = 0; 355 356 Elf_Sym const *const symp = 357 &sym0[Elf_r_sym(relp)]; 358 char const *symname = &str0[w(symp->st 359 char const *mcount = gpfx == '_' ? "_m 360 char const *fentry = "__fentry__"; 361 362 if (symname[0] == '.') 363 ++symname; /* ppc64 hack */ 364 if (strcmp(mcount, symname) == 0 || 365 (altmcount && strcmp(altmcount, sy 366 (strcmp(fentry, symname) == 0)) 367 mcountsym = Elf_r_sym(relp); 368 369 return mcountsym; 370 } 371 372 static void get_sym_str_and_relp(Elf_Shdr cons 373 Elf_Ehdr cons 374 Elf_Sym const 375 char const ** 376 Elf_Rel const 377 { 378 Elf_Shdr *const shdr0 = (Elf_Shdr *)(_ 379 + (void *)ehdr); 380 unsigned const symsec_sh_link = w(relh 381 Elf_Shdr const *const symsec = &shdr0[ 382 Elf_Shdr const *const strsec = &shdr0[ 383 Elf_Rel const *const rel0 = (Elf_Rel c 384 + (void *)ehdr); 385 386 *sym0 = (Elf_Sym const *)(_w(symsec->s 387 + (void *)eh 388 389 *str0 = (char const *)(_w(strsec->sh_o 390 + (void *)ehdr) 391 392 *relp = rel0; 393 } 394 395 /* 396 * Look at the relocations in order to find th 397 * Accumulate the section offsets that are fou 398 * onto the end of the existing arrays. 399 */ 400 static uint_t *sift_rel_mcount(uint_t *mlocp, 401 unsigned const 402 Elf_Rel **const 403 Elf_Shdr const 404 Elf_Ehdr const 405 unsigned const 406 uint_t const re 407 unsigned const 408 { 409 uint_t *const mloc0 = mlocp; 410 Elf_Rel *mrelp = *mrelpp; 411 Elf_Sym const *sym0; 412 char const *str0; 413 Elf_Rel const *relp; 414 unsigned rel_entsize = _w(relhdr->sh_e 415 unsigned const nrel = _w(relhdr->sh_si 416 unsigned mcountsym = 0; 417 unsigned t; 418 419 get_sym_str_and_relp(relhdr, ehdr, &sy 420 421 for (t = nrel; t; --t) { 422 if (!mcountsym) 423 mcountsym = get_mcount 424 425 if (mcountsym && mcountsym == 426 !is_fake_mcoun 427 uint_t const addend = 428 _w(_w(relp->r_ 429 mrelp->r_offset = _w(o 430 + ((void *)mlo 431 Elf_r_info(mrelp, recs 432 if (rel_entsize == siz 433 ((Elf_Rela *)m 434 *mlocp++ = 0; 435 } else 436 *mlocp++ = add 437 438 mrelp = (Elf_Rel *)(re 439 } 440 relp = (Elf_Rel const *)(rel_e 441 } 442 *mrelpp = mrelp; 443 return mlocp; 444 } 445 446 /* 447 * Read the relocation table again, but this t 448 * that are not going to be traced. The mcount 449 * into nops. 450 */ 451 static int nop_mcount(Elf_Shdr const *const re 452 Elf_Ehdr const *const eh 453 const char *const txtnam 454 { 455 Elf_Shdr *const shdr0 = (Elf_Shdr *)(_ 456 + (void *)ehdr); 457 Elf_Sym const *sym0; 458 char const *str0; 459 Elf_Rel const *relp; 460 Elf_Shdr const *const shdr = &shdr0[w( 461 unsigned rel_entsize = _w(relhdr->sh_e 462 unsigned const nrel = _w(relhdr->sh_si 463 unsigned mcountsym = 0; 464 unsigned t; 465 int once = 0; 466 467 get_sym_str_and_relp(relhdr, ehdr, &sy 468 469 for (t = nrel; t; --t) { 470 int ret = -1; 471 472 if (!mcountsym) 473 mcountsym = get_mcount 474 475 if (mcountsym == Elf_r_sym(rel 476 if (make_nop) 477 ret = make_nop 478 if (warn_on_notrace_se 479 printf("Sectio 480 txtname 481 once = 1; 482 /* just warn? 483 if (!make_nop) 484 return 485 } 486 } 487 488 /* 489 * If we successfully removed 490 * as a nop (don't do anything 491 */ 492 if (!ret) { 493 Elf_Rel rel; 494 rel = *(Elf_Rel *)relp 495 Elf_r_info(&rel, Elf_r 496 if (ulseek((void *)rel 497 return -1; 498 if (uwrite(&rel, sizeo 499 return -1; 500 } 501 relp = (Elf_Rel const *)(rel_e 502 } 503 return 0; 504 } 505 506 /* 507 * Find a symbol in the given section, to be u 508 * the table of offsets of calls to mcount. A 509 * but avoid a Weak symbol because it may be o 510 * would invalidate the relocations of the off 511 * Often the found symbol will be the unnamed 512 * GNU 'as' for the start of each section. Fo 513 * Num: Value Size Type Bind Vis 514 * 2: 00000000 0 SECTION LOCAL DEFAU 515 */ 516 static int find_secsym_ndx(unsigned const txtn 517 char const *co 518 uint_t *const 519 unsigned int * 520 Elf_Shdr const 521 Elf32_Word con 522 Elf32_Word con 523 Elf_Ehdr const 524 { 525 Elf_Sym const *const sym0 = (Elf_Sym c 526 + (void *)ehdr); 527 unsigned const nsym = _w(symhdr->sh_si 528 Elf_Sym const *symp; 529 unsigned t; 530 531 for (symp = sym0, t = nsym; t; --t, ++ 532 unsigned int const st_bind = E 533 534 if (txtndx == get_symindex(sym 535 /* avoid STB_WEAK */ 536 && (STB_LOCAL == st_bind | 537 /* function symbols on 538 if (w2(ehdr->e_machine 539 && ELF_ST_TYPE(sym 540 continue; 541 542 *recvalp = _w(symp->st 543 *sym_index = symp - sy 544 return 0; 545 } 546 } 547 fprintf(stderr, "Cannot find symbol fo 548 txtndx, txtname); 549 return -1; 550 } 551 552 /* Evade ISO C restriction: no declaration aft 553 static char const * __has_rel_mcount(Elf_Shdr 554 Elf_Shdr 555 char cons 556 char cons 557 { 558 /* .sh_info depends on .sh_type == SHT 559 Elf_Shdr const *const txthdr = &shdr0[ 560 char const *const txtname = &shstrtab[ 561 562 if (strcmp("__mcount_loc", txtname) == 563 fprintf(stderr, "warning: __mc 564 fname); 565 return already_has_rel_mcount; 566 } 567 if (w(txthdr->sh_type) != SHT_PROGBITS 568 !(_w(txthdr->sh_flags) & SHF_EXECI 569 return NULL; 570 return txtname; 571 } 572 573 static char const *has_rel_mcount(Elf_Shdr con 574 Elf_Shdr con 575 char const * 576 char const * 577 { 578 if (w(relhdr->sh_type) != SHT_REL && w 579 return NULL; 580 return __has_rel_mcount(relhdr, shdr0, 581 } 582 583 584 static unsigned tot_relsize(Elf_Shdr const *co 585 unsigned nhdr, 586 const char *const 587 const char *const 588 { 589 unsigned totrelsz = 0; 590 Elf_Shdr const *shdrp = shdr0; 591 char const *txtname; 592 593 for (; nhdr; --nhdr, ++shdrp) { 594 txtname = has_rel_mcount(shdrp 595 if (txtname == already_has_rel 596 totrelsz = 0; 597 break; 598 } 599 if (txtname && is_mcounted_sec 600 totrelsz += _w(shdrp-> 601 } 602 return totrelsz; 603 } 604 605 /* Overall supervision for Elf32 ET_REL file. 606 static int do_func(Elf_Ehdr *const ehdr, char 607 unsigned const reltype) 608 { 609 Elf_Shdr *const shdr0 = (Elf_Shdr *)(_ 610 + (void *)ehdr); 611 unsigned const nhdr = get_shnum(ehdr, 612 Elf_Shdr *const shstr = &shdr0[get_shs 613 char const *const shstrtab = (char con 614 + (void *)ehdr); 615 616 Elf_Shdr const *relhdr; 617 unsigned k; 618 619 Elf32_Word *symtab; 620 Elf32_Word *symtab_shndx; 621 622 /* Upper bound on space: assume all re 623 unsigned totrelsz; 624 625 Elf_Rel * mrel0; 626 Elf_Rel * mrelp; 627 628 uint_t * mloc0; 629 uint_t * mlocp; 630 631 unsigned rel_entsize = 0; 632 unsigned symsec_sh_link = 0; 633 634 int result = 0; 635 636 totrelsz = tot_relsize(shdr0, nhdr, sh 637 if (totrelsz == 0) 638 return 0; 639 mrel0 = umalloc(totrelsz); 640 mrelp = mrel0; 641 if (!mrel0) 642 return -1; 643 644 /* 2*sizeof(address) <= sizeof(Elf_Rel 645 mloc0 = umalloc(totrelsz>>1); 646 mlocp = mloc0; 647 if (!mloc0) { 648 free(mrel0); 649 return -1; 650 } 651 652 find_symtab(ehdr, shdr0, nhdr, &symtab 653 654 for (relhdr = shdr0, k = nhdr; k; --k, 655 char const *const txtname = ha 656 shstrtab, fname); 657 if (txtname == already_has_rel 658 result = 0; 659 file_updated = 0; 660 goto out; /* Nothing t 661 } 662 if (txtname && is_mcounted_sec 663 unsigned int recsym; 664 uint_t recval = 0; 665 666 symsec_sh_link = w(rel 667 result = find_secsym_n 668 669 670 671 672 if (result) 673 goto out; 674 675 rel_entsize = _w(relhd 676 mlocp = sift_rel_mcoun 677 (void *)mlocp 678 relhdr, ehdr, 679 } else if (txtname && (warn_on 680 /* 681 * This section is ign 682 * has mcount calls. C 683 */ 684 if (nop_mcount(relhdr, 685 result = -1; 686 goto out; 687 } 688 } 689 } 690 if (!result && mloc0 != mlocp) 691 result = append_func(ehdr, shs 692 rel_entsi 693 out: 694 free(mrel0); 695 free(mloc0); 696 return result; 697 } 698
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