1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * recordmcount.h 4 * 5 * This code was taken out of recordmcount.c written by 6 * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved. 7 * 8 * The original code had the same algorithms for both 32bit 9 * and 64bit ELF files, but the code was duplicated to support 10 * the difference in structures that were used. This 11 * file creates a macro of everything that is different between 12 * the 64 and 32 bit code, such that by including this header 13 * twice we can create both sets of functions by including this 14 * header once with RECORD_MCOUNT_64 undefined, and again with 15 * it defined. 16 * 17 * This conversion to macros was done by: 18 * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc. 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_mcount 61# define nop_mcount nop_mcount_64 62# define find_secsym_ndx find64_secsym_ndx 63# define __has_rel_mcount __has64_rel_mcount 64# define has_rel_mcount has64_rel_mcount 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_and_relp_64 72# define do_func do64 73# define get_mcountsym get_mcountsym_64 74# define is_fake_mcount is_fake_mcount64 75# define fn_is_fake_mcount fn_is_fake_mcount64 76# define MIPS_is_fake_mcount MIPS64_is_fake_mcount 77# define mcount_adjust mcount_adjust_64 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_INFO 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_mcount 99# define nop_mcount nop_mcount_32 100# define find_secsym_ndx find32_secsym_ndx 101# define __has_rel_mcount __has32_rel_mcount 102# define has_rel_mcount has32_rel_mcount 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_and_relp_32 110# define do_func do32 111# define get_mcountsym get_mcountsym_32 112# define is_fake_mcount is_fake_mcount32 113# define fn_is_fake_mcount fn_is_fake_mcount32 114# define MIPS_is_fake_mcount MIPS32_is_fake_mcount 115# define mcount_adjust mcount_adjust_32 116# 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_INFO 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 override for specific e_machine. */ 137static int fn_is_fake_mcount(Elf_Rel const *rp) 138{ 139 return 0; 140} 141static int (*is_fake_mcount)(Elf_Rel const *rp) = fn_is_fake_mcount; 142 143static uint_t fn_ELF_R_SYM(Elf_Rel const *rp) 144{ 145 return ELF_R_SYM(_w(rp->r_info)); 146} 147static uint_t (*Elf_r_sym)(Elf_Rel const *rp) = fn_ELF_R_SYM; 148 149static void fn_ELF_R_INFO(Elf_Rel *const rp, unsigned sym, unsigned type) 150{ 151 rp->r_info = _w(ELF_R_INFO(sym, type)); 152} 153static void (*Elf_r_info)(Elf_Rel *const rp, unsigned sym, unsigned type) = fn_ELF_R_INFO; 154 155static int mcount_adjust = 0; 156 157/* 158 * MIPS mcount long call has 2 _mcount symbols, only the position of the 1st 159 * _mcount symbol is needed for dynamic function tracer, with it, to disable 160 * tracing(ftrace_make_nop), the instruction in the position is replaced with 161 * the "b label" instruction, to enable tracing(ftrace_make_call), replace the 162 * instruction back. So, here, we set the 2nd one as fake and filter it. 163 * 164 * c: 3c030000 lui v1,0x0 <--> b label 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 178static int MIPS_is_fake_mcount(Elf_Rel const *rp) 179{ 180 static Elf_Addr old_r_offset = ~(Elf_Addr)0; 181 Elf_Addr current_r_offset = _w(rp->r_offset); 182 int is_fake; 183 184 is_fake = (old_r_offset != ~(Elf_Addr)0) && 185 (current_r_offset - old_r_offset == MIPS_FAKEMCOUNT_OFFSET); 186 old_r_offset = current_r_offset; 187 188 return is_fake; 189} 190 191static unsigned int get_symindex(Elf_Sym const *sym, Elf32_Word const *symtab, 192 Elf32_Word const *symtab_shndx) 193{ 194 unsigned long offset; 195 unsigned short shndx = w2(sym->st_shndx); 196 int index; 197 198 if (shndx > SHN_UNDEF && shndx < SHN_LORESERVE) 199 return shndx; 200 201 if (shndx == SHN_XINDEX) { 202 offset = (unsigned long)sym - (unsigned long)symtab; 203 index = offset / sizeof(*sym); 204 205 return w(symtab_shndx[index]); 206 } 207 208 return 0; 209} 210 211static unsigned int get_shnum(Elf_Ehdr const *ehdr, Elf_Shdr const *shdr0) 212{ 213 if (shdr0 && !ehdr->e_shnum) 214 return w(shdr0->sh_size); 215 216 return w2(ehdr->e_shnum); 217} 218 219static void set_shnum(Elf_Ehdr *ehdr, Elf_Shdr *shdr0, unsigned int new_shnum) 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 228static int get_shstrndx(Elf_Ehdr const *ehdr, Elf_Shdr const *shdr0) 229{ 230 if (ehdr->e_shstrndx != SHN_XINDEX) 231 return w2(ehdr->e_shstrndx); 232 233 return w(shdr0->sh_link); 234} 235 236static void find_symtab(Elf_Ehdr *const ehdr, Elf_Shdr const *shdr0, 237 unsigned const nhdr, Elf32_Word **symtab, 238 Elf32_Word **symtab_shndx) 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, ++relhdr) { 247 if (relhdr->sh_type == SHT_SYMTAB) 248 *symtab = (void *)ehdr + relhdr->sh_offset; 249 else if (relhdr->sh_type == SHT_SYMTAB_SHNDX) 250 *symtab_shndx = (void *)ehdr + relhdr->sh_offset; 251 252 if (*symtab && *symtab_shndx) 253 break; 254 } 255} 256 257/* Append the new shstrtab, Elf_Shdr[], __mcount_loc and its relocations. */ 258static int append_func(Elf_Ehdr *const ehdr, 259 Elf_Shdr *const shstr, 260 uint_t const *const mloc0, 261 uint_t const *const mlocp, 262 Elf_Rel const *const mrel0, 263 Elf_Rel const *const mrelp, 264 unsigned int const rel_entsize, 265 unsigned int const symsec_sh_link) 266{ 267 /* Begin constructing output file */ 268 Elf_Shdr mcsec; 269 char const *mc_name = (sizeof(Elf_Rela) == rel_entsize) 270 ? ".rela__mcount_loc" 271 : ".rel__mcount_loc"; 272 uint_t const old_shoff = _w(ehdr->e_shoff); 273 uint_t const old_shstr_sh_size = _w(shstr->sh_size); 274 uint_t const old_shstr_sh_offset = _w(shstr->sh_offset); 275 Elf_Shdr *const shdr0 = (Elf_Shdr *)(old_shoff + (void *)ehdr); 276 unsigned int const old_shnum = get_shnum(ehdr, shdr0); 277 unsigned int const new_shnum = 2 + old_shnum; /* {.rel,}__mcount_loc */ 278 uint_t t = 1 + strlen(mc_name) + _w(shstr->sh_size); 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 align */ 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 *)ehdr, old_shstr_sh_size) < 0) 293 return -1; 294 if (uwrite(mc_name, 1 + strlen(mc_name)) < 0) 295 return -1; 296 297 /* old(modified) Elf_Shdr table, word-byte aligned */ 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) < 0) 303 return -1; 304 305 /* new sections __mcount_loc and .rel__mcount_loc */ 306 t += 2*sizeof(mcsec); 307 mcsec.sh_name = w((sizeof(Elf_Rela) == rel_entsize) + strlen(".rel") 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 - (void *)mloc0); 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) == rel_entsize) 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 - (void *)mloc0 + t); 328 mcsec.sh_size = _w((void *)mrelp - (void *)mrel0); 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 - (void *)mloc0) < 0) 338 return -1; 339 if (uwrite(mrel0, (void *)mrelp - (void *)mrel0) < 0) 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 350static unsigned get_mcountsym(Elf_Sym const *const sym0, 351 Elf_Rel const *relp, 352 char const *const str0) 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_name)]; 359 char const *mcount = gpfx == '_' ? "_mcount" : "mcount"; 360 char const *fentry = "__fentry__"; 361 362 if (symname[0] == '.') 363 ++symname; /* ppc64 hack */ 364 if (strcmp(mcount, symname) == 0 || 365 (altmcount && strcmp(altmcount, symname) == 0) || 366 (strcmp(fentry, symname) == 0)) 367 mcountsym = Elf_r_sym(relp); 368 369 return mcountsym; 370} 371 372static void get_sym_str_and_relp(Elf_Shdr const *const relhdr, 373 Elf_Ehdr const *const ehdr, 374 Elf_Sym const **sym0, 375 char const **str0, 376 Elf_Rel const **relp) 377{ 378 Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff) 379 + (void *)ehdr); 380 unsigned const symsec_sh_link = w(relhdr->sh_link); 381 Elf_Shdr const *const symsec = &shdr0[symsec_sh_link]; 382 Elf_Shdr const *const strsec = &shdr0[w(symsec->sh_link)]; 383 Elf_Rel const *const rel0 = (Elf_Rel const *)(_w(relhdr->sh_offset) 384 + (void *)ehdr); 385 386 *sym0 = (Elf_Sym const *)(_w(symsec->sh_offset) 387 + (void *)ehdr); 388 389 *str0 = (char const *)(_w(strsec->sh_offset) 390 + (void *)ehdr); 391 392 *relp = rel0; 393} 394 395/* 396 * Look at the relocations in order to find the calls to mcount. 397 * Accumulate the section offsets that are found, and their relocation info, 398 * onto the end of the existing arrays. 399 */ 400static uint_t *sift_rel_mcount(uint_t *mlocp, 401 unsigned const offbase, 402 Elf_Rel **const mrelpp, 403 Elf_Shdr const *const relhdr, 404 Elf_Ehdr const *const ehdr, 405 unsigned const recsym, 406 uint_t const recval, 407 unsigned const reltype) 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_entsize); 415 unsigned const nrel = _w(relhdr->sh_size) / rel_entsize; 416 unsigned mcountsym = 0; 417 unsigned t; 418 419 get_sym_str_and_relp(relhdr, ehdr, &sym0, &str0, &relp); 420 421 for (t = nrel; t; --t) { 422 if (!mcountsym) 423 mcountsym = get_mcountsym(sym0, relp, str0); 424 425 if (mcountsym && mcountsym == Elf_r_sym(relp) && 426 !is_fake_mcount(relp)) { 427 uint_t const addend = 428 _w(_w(relp->r_offset) - recval + mcount_adjust); 429 mrelp->r_offset = _w(offbase 430 + ((void *)mlocp - (void *)mloc0)); 431 Elf_r_info(mrelp, recsym, reltype); 432 if (rel_entsize == sizeof(Elf_Rela)) { 433 ((Elf_Rela *)mrelp)->r_addend = addend; 434 *mlocp++ = 0; 435 } else 436 *mlocp++ = addend; 437 438 mrelp = (Elf_Rel *)(rel_entsize + (void *)mrelp); 439 } 440 relp = (Elf_Rel const *)(rel_entsize + (void *)relp); 441 } 442 *mrelpp = mrelp; 443 return mlocp; 444} 445 446/* 447 * Read the relocation table again, but this time its called on sections 448 * that are not going to be traced. The mcount calls here will be converted 449 * into nops. 450 */ 451static int nop_mcount(Elf_Shdr const *const relhdr, 452 Elf_Ehdr const *const ehdr, 453 const char *const txtname) 454{ 455 Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff) 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(relhdr->sh_info)]; 461 unsigned rel_entsize = _w(relhdr->sh_entsize); 462 unsigned const nrel = _w(relhdr->sh_size) / rel_entsize; 463 unsigned mcountsym = 0; 464 unsigned t; 465 int once = 0; 466 467 get_sym_str_and_relp(relhdr, ehdr, &sym0, &str0, &relp); 468 469 for (t = nrel; t; --t) { 470 int ret = -1; 471 472 if (!mcountsym) 473 mcountsym = get_mcountsym(sym0, relp, str0); 474 475 if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) { 476 if (make_nop) 477 ret = make_nop((void *)ehdr, _w(shdr->sh_offset) + _w(relp->r_offset)); 478 if (warn_on_notrace_sect && !once) { 479 printf("Section %s has mcount callers being ignored\n", 480 txtname); 481 once = 1; 482 /* just warn? */ 483 if (!make_nop) 484 return 0; 485 } 486 } 487 488 /* 489 * If we successfully removed the mcount, mark the relocation 490 * as a nop (don't do anything with it). 491 */ 492 if (!ret) { 493 Elf_Rel rel; 494 rel = *(Elf_Rel *)relp; 495 Elf_r_info(&rel, Elf_r_sym(relp), rel_type_nop); 496 if (ulseek((void *)relp - (void *)ehdr, SEEK_SET) < 0) 497 return -1; 498 if (uwrite(&rel, sizeof(rel)) < 0) 499 return -1; 500 } 501 relp = (Elf_Rel const *)(rel_entsize + (void *)relp); 502 } 503 return 0; 504} 505 506/* 507 * Find a symbol in the given section, to be used as the base for relocating 508 * the table of offsets of calls to mcount. A local or global symbol suffices, 509 * but avoid a Weak symbol because it may be overridden; the change in value 510 * would invalidate the relocations of the offsets of the calls to mcount. 511 * Often the found symbol will be the unnamed local symbol generated by 512 * GNU 'as' for the start of each section. For example: 513 * Num: Value Size Type Bind Vis Ndx Name 514 * 2: 00000000 0 SECTION LOCAL DEFAULT 1 515 */ 516static int find_secsym_ndx(unsigned const txtndx, 517 char const *const txtname, 518 uint_t *const recvalp, 519 unsigned int *sym_index, 520 Elf_Shdr const *const symhdr, 521 Elf32_Word const *symtab, 522 Elf32_Word const *symtab_shndx, 523 Elf_Ehdr const *const ehdr) 524{ 525 Elf_Sym const *const sym0 = (Elf_Sym const *)(_w(symhdr->sh_offset) 526 + (void *)ehdr); 527 unsigned const nsym = _w(symhdr->sh_size) / _w(symhdr->sh_entsize); 528 Elf_Sym const *symp; 529 unsigned t; 530 531 for (symp = sym0, t = nsym; t; --t, ++symp) { 532 unsigned int const st_bind = ELF_ST_BIND(symp->st_info); 533 534 if (txtndx == get_symindex(symp, symtab, symtab_shndx) 535 /* avoid STB_WEAK */ 536 && (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) { 537 /* function symbols on ARM have quirks, avoid them */ 538 if (w2(ehdr->e_machine) == EM_ARM 539 && ELF_ST_TYPE(symp->st_info) == STT_FUNC) 540 continue; 541 542 *recvalp = _w(symp->st_value); 543 *sym_index = symp - sym0; 544 return 0; 545 } 546 } 547 fprintf(stderr, "Cannot find symbol for section %u: %s.\n", 548 txtndx, txtname); 549 return -1; 550} 551 552/* Evade ISO C restriction: no declaration after statement in has_rel_mcount. */ 553static char const * __has_rel_mcount(Elf_Shdr const *const relhdr, /* reltype */ 554 Elf_Shdr const *const shdr0, 555 char const *const shstrtab, 556 char const *const fname) 557{ 558 /* .sh_info depends on .sh_type == SHT_REL[,A] */ 559 Elf_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)]; 560 char const *const txtname = &shstrtab[w(txthdr->sh_name)]; 561 562 if (strcmp("__mcount_loc", txtname) == 0) { 563 fprintf(stderr, "warning: __mcount_loc already exists: %s\n", 564 fname); 565 return already_has_rel_mcount; 566 } 567 if (w(txthdr->sh_type) != SHT_PROGBITS || 568 !(_w(txthdr->sh_flags) & SHF_EXECINSTR)) 569 return NULL; 570 return txtname; 571} 572 573static char const *has_rel_mcount(Elf_Shdr const *const relhdr, 574 Elf_Shdr const *const shdr0, 575 char const *const shstrtab, 576 char const *const fname) 577{ 578 if (w(relhdr->sh_type) != SHT_REL && w(relhdr->sh_type) != SHT_RELA) 579 return NULL; 580 return __has_rel_mcount(relhdr, shdr0, shstrtab, fname); 581} 582 583 584static unsigned tot_relsize(Elf_Shdr const *const shdr0, 585 unsigned nhdr, 586 const char *const shstrtab, 587 const char *const fname) 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, shdr0, shstrtab, fname); 595 if (txtname == already_has_rel_mcount) { 596 totrelsz = 0; 597 break; 598 } 599 if (txtname && is_mcounted_section_name(txtname)) 600 totrelsz += _w(shdrp->sh_size); 601 } 602 return totrelsz; 603} 604 605/* Overall supervision for Elf32 ET_REL file. */ 606static int do_func(Elf_Ehdr *const ehdr, char const *const fname, 607 unsigned const reltype) 608{ 609 Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff) 610 + (void *)ehdr); 611 unsigned const nhdr = get_shnum(ehdr, shdr0); 612 Elf_Shdr *const shstr = &shdr0[get_shstrndx(ehdr, shdr0)]; 613 char const *const shstrtab = (char const *)(_w(shstr->sh_offset) 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 relevant relocs are for mcount. */ 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, shstrtab, fname); 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, &symtab_shndx); 653 654 for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) { 655 char const *const txtname = has_rel_mcount(relhdr, shdr0, 656 shstrtab, fname); 657 if (txtname == already_has_rel_mcount) { 658 result = 0; 659 file_updated = 0; 660 goto out; /* Nothing to be done; don't append! */ 661 } 662 if (txtname && is_mcounted_section_name(txtname)) { 663 unsigned int recsym; 664 uint_t recval = 0; 665 666 symsec_sh_link = w(relhdr->sh_link); 667 result = find_secsym_ndx(w(relhdr->sh_info), txtname, 668 &recval, &recsym, 669 &shdr0[symsec_sh_link], 670 symtab, symtab_shndx, 671 ehdr); 672 if (result) 673 goto out; 674 675 rel_entsize = _w(relhdr->sh_entsize); 676 mlocp = sift_rel_mcount(mlocp, 677 (void *)mlocp - (void *)mloc0, &mrelp, 678 relhdr, ehdr, recsym, recval, reltype); 679 } else if (txtname && (warn_on_notrace_sect || make_nop)) { 680 /* 681 * This section is ignored by ftrace, but still 682 * has mcount calls. Convert them to nops now. 683 */ 684 if (nop_mcount(relhdr, ehdr, txtname) < 0) { 685 result = -1; 686 goto out; 687 } 688 } 689 } 690 if (!result && mloc0 != mlocp) 691 result = append_func(ehdr, shstr, mloc0, mlocp, mrel0, mrelp, 692 rel_entsize, symsec_sh_link); 693out: 694 free(mrel0); 695 free(mloc0); 696 return result; 697} 698