1 /* x86 specific support for ELF 2 Copyright (C) 2017-2022 Free Software Foundation, Inc. 3 4 This file is part of BFD, the Binary File Descriptor library. 5 6 This program is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3 of the License, or 9 (at your option) any later version. 10 11 This program is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with this program; if not, write to the Free Software 18 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 19 MA 02110-1301, USA. */ 20 21 /* Don't generate unused section symbols. */ 22 #define TARGET_KEEP_UNUSED_SECTION_SYMBOLS false 23 24 #include "sysdep.h" 25 #include "bfd.h" 26 #include "bfdlink.h" 27 #include "libbfd.h" 28 #include "elf-bfd.h" 29 #include "hashtab.h" 30 #include "elf-linker-x86.h" 31 #include "elf/i386.h" 32 #include "elf/x86-64.h" 33 #include "sframe-api.h" 34 35 #define X86_64_PCREL_TYPE_P(TYPE) \ 36 ((TYPE) == R_X86_64_PC8 \ 37 || (TYPE) == R_X86_64_PC16 \ 38 || (TYPE) == R_X86_64_PC32 \ 39 || (TYPE) == R_X86_64_PC64) 40 #define I386_PCREL_TYPE_P(TYPE) ((TYPE) == R_386_PC32) 41 #define X86_PCREL_TYPE_P(IS_X86_64, TYPE) \ 42 ((IS_X86_64) ? X86_64_PCREL_TYPE_P (TYPE) : I386_PCREL_TYPE_P (TYPE)) 43 44 #define X86_64_SIZE_TYPE_P(TYPE) \ 45 ((TYPE) == R_X86_64_SIZE32 || (TYPE) == R_X86_64_SIZE64) 46 #define I386_SIZE_TYPE_P(TYPE) ((TYPE) == R_386_SIZE32) 47 #define X86_SIZE_TYPE_P(IS_X86_64, TYPE) \ 48 ((IS_X86_64) ? X86_64_SIZE_TYPE_P(TYPE) : I386_SIZE_TYPE_P (TYPE)) 49 50 #define X86_64_GOT_TYPE_P(TYPE) \ 51 ((TYPE) == R_X86_64_GOTPCREL \ 52 || (TYPE) == R_X86_64_GOTPCRELX \ 53 || (TYPE) == R_X86_64_REX_GOTPCRELX \ 54 || (TYPE) == R_X86_64_GOT32 \ 55 || (TYPE) == R_X86_64_GOT64 \ 56 || (TYPE) == R_X86_64_GOTPCREL64 \ 57 || (TYPE) == R_X86_64_GOTPLT64) 58 #define I386_GOT_TYPE_P(TYPE) \ 59 ((TYPE) == R_386_GOT32 || (TYPE) == R_386_GOT32X) 60 #define X86_GOT_TYPE_P(IS_X86_64, TYPE) \ 61 ((IS_X86_64) ? X86_64_GOT_TYPE_P (TYPE) : I386_GOT_TYPE_P (TYPE)) 62 63 #define X86_64_RELATIVE_RELOC_TYPE_P(TYPE) \ 64 (X86_64_PCREL_TYPE_P (TYPE) \ 65 || (TYPE) == R_X86_64_8 \ 66 || (TYPE) == R_X86_64_16 \ 67 || (TYPE) == R_X86_64_32 \ 68 || (TYPE) == R_X86_64_32S \ 69 || (TYPE) == R_X86_64_64) 70 #define I386_RELATIVE_RELOC_TYPE_P(TYPE) \ 71 ((TYPE) == R_386_32 || (TYPE) == R_386_PC32) 72 #define X86_RELATIVE_RELOC_TYPE_P(IS_X86_64, TYPE) \ 73 ((IS_X86_64) \ 74 ? X86_64_RELATIVE_RELOC_TYPE_P (TYPE) \ 75 : I386_RELATIVE_RELOC_TYPE_P(TYPE)) 76 77 #define X86_64_NEED_DYNAMIC_RELOC_TYPE_P(TYPE) \ 78 (X86_64_SIZE_TYPE_P (TYPE) \ 79 || X86_64_RELATIVE_RELOC_TYPE_P (TYPE)) 80 #define I386_NEED_DYNAMIC_RELOC_TYPE_P(TYPE) \ 81 (I386_SIZE_TYPE_P (TYPE) \ 82 || I386_RELATIVE_RELOC_TYPE_P (TYPE) \ 83 || (TYPE) == R_386_TLS_IE \ 84 || (TYPE) == R_386_TLS_LE \ 85 || (TYPE) == R_386_TLS_LE_32) 86 #define X86_NEED_DYNAMIC_RELOC_TYPE_P(IS_X86_64, TYPE) \ 87 ((IS_X86_64) \ 88 ? X86_64_NEED_DYNAMIC_RELOC_TYPE_P (TYPE) \ 89 : I386_NEED_DYNAMIC_RELOC_TYPE_P (TYPE)) 90 91 #define X86_LOCAL_GOT_RELATIVE_RELOC_P(IS_X86_64, INFO, SYM) \ 92 (bfd_link_pic (INFO) \ 93 && (!(IS_X86_64) || ((SYM) != NULL && (SYM)->st_shndx != SHN_ABS))) 94 95 #define PLT_CIE_LENGTH 20 96 #define PLT_FDE_LENGTH 36 97 #define PLT_FDE_START_OFFSET 4 + PLT_CIE_LENGTH + 8 98 #define PLT_FDE_LEN_OFFSET 4 + PLT_CIE_LENGTH + 12 99 100 #define I386_PCREL_TYPE_P(TYPE) ((TYPE) == R_386_PC32) 101 #define X86_64_PCREL_TYPE_P(TYPE) \ 102 ((TYPE) == R_X86_64_PC8 \ 103 || (TYPE) == R_X86_64_PC16 \ 104 || (TYPE) == R_X86_64_PC32 \ 105 || (TYPE) == R_X86_64_PC64) 106 107 /* This must be the same as sframe_get_hdr_size (sfh). For x86-64, this value 108 is the same as sizeof (sframe_header) because there is no SFrame auxilliary 109 header. */ 110 #define PLT_SFRAME_FDE_START_OFFSET sizeof (sframe_header) 111 112 #define ABI_64_P(abfd) \ 113 (get_elf_backend_data (abfd)->s->elfclass == ELFCLASS64) 114 115 /* If ELIMINATE_COPY_RELOCS is non-zero, the linker will try to avoid 116 copying dynamic variables from a shared lib into an app's dynbss 117 section, and instead use a dynamic relocation to point into the 118 shared lib. */ 119 #define ELIMINATE_COPY_RELOCS 1 120 121 #define elf_x86_hash_table(p, id) \ 122 (is_elf_hash_table ((p)->hash) \ 123 && elf_hash_table_id ((struct elf_link_hash_table *) ((p)->hash)) == (id) \ 124 ? ((struct elf_x86_link_hash_table *) ((p)->hash)) : NULL) 125 126 /* Will references to this symbol always be local in this object? */ 127 #define SYMBOL_REFERENCES_LOCAL_P(INFO, H) \ 128 _bfd_x86_elf_link_symbol_references_local ((INFO), (H)) 129 130 /* TRUE if an undefined weak symbol should be resolved to 0. Local 131 undefined weak symbol is always resolved to 0. Reference to an 132 undefined weak symbol is resolved to 0 in executable if undefined 133 weak symbol should be resolved to 0 (zero_undefweak > 0). */ 134 #define UNDEFINED_WEAK_RESOLVED_TO_ZERO(INFO, EH) \ 135 ((EH)->elf.root.type == bfd_link_hash_undefweak \ 136 && (SYMBOL_REFERENCES_LOCAL_P ((INFO), &(EH)->elf) \ 137 || (bfd_link_executable (INFO) \ 138 && (EH)->zero_undefweak > 0))) 139 140 /* Should copy relocation be generated for a symbol. Don't generate 141 copy relocation against a protected symbol defined in a shared 142 object. */ 143 #define SYMBOL_NO_COPYRELOC(INFO, EH) \ 144 ((EH)->def_protected \ 145 && ((EH)->elf.root.type == bfd_link_hash_defined \ 146 || (EH)->elf.root.type == bfd_link_hash_defweak) \ 147 && ((EH)->elf.root.u.def.section->owner->flags & DYNAMIC) != 0 \ 148 && ((EH)->elf.root.u.def.section->flags & SEC_CODE) == 0) 149 150 /* TRUE if dynamic relocation is needed. If we are creating a shared 151 library, and this is a reloc against a global symbol, or a non PC 152 relative reloc against a local symbol, then we need to copy the reloc 153 into the shared library. However, if we are linking with -Bsymbolic, 154 we do not need to copy a reloc against a global symbol which is 155 defined in an object we are including in the link (i.e., DEF_REGULAR 156 is set). 157 158 If PCREL_PLT is true, don't generate dynamic relocation in PIE for 159 PC-relative relocation against a dynamic function definition in data 160 section when PLT address can be used. 161 162 If on the other hand, we are creating an executable, we may need to 163 keep relocations for symbols satisfied by a dynamic library if we 164 manage to avoid copy relocs for the symbol. 165 166 We also need to generate dynamic pointer relocation against 167 STT_GNU_IFUNC symbol in the non-code section. */ 168 #define NEED_DYNAMIC_RELOCATION_P(IS_X86_64, INFO, PCREL_PLT, H, SEC, \ 169 R_TYPE, POINTER_TYPE) \ 170 ((bfd_link_pic (INFO) \ 171 && (! X86_PCREL_TYPE_P (IS_X86_64, R_TYPE) \ 172 || ((H) != NULL \ 173 && (! (bfd_link_pie (INFO) \ 174 || SYMBOLIC_BIND ((INFO), (H))) \ 175 || (H)->root.type == bfd_link_hash_defweak \ 176 || (!(bfd_link_pie (INFO) \ 177 && (PCREL_PLT) \ 178 && (H)->plt.refcount > 0 \ 179 && ((SEC)->flags & SEC_CODE) == 0 \ 180 && (H)->type == STT_FUNC \ 181 && (H)->def_dynamic) \ 182 && !(H)->def_regular))))) \ 183 || ((H) != NULL \ 184 && (H)->type == STT_GNU_IFUNC \ 185 && (R_TYPE) == POINTER_TYPE \ 186 && ((SEC)->flags & SEC_CODE) == 0) \ 187 || (ELIMINATE_COPY_RELOCS \ 188 && !bfd_link_pic (INFO) \ 189 && (H) != NULL \ 190 && ((H)->root.type == bfd_link_hash_defweak \ 191 || !(H)->def_regular))) 192 193 /* TRUE if dynamic relocation should be generated. Don't copy a 194 pc-relative relocation into the output file if the symbol needs 195 copy reloc or the symbol is undefined when building executable. 196 Copy dynamic function pointer relocations. Don't generate dynamic 197 relocations against resolved undefined weak symbols in PIE, except 198 when PC32_RELOC is TRUE. Undefined weak symbol is bound locally 199 when PIC is false. Don't generate dynamic relocations against 200 non-preemptible absolute symbol. NB: rel_from_abs is set on symbols 201 defined by linker scripts from "dot" (also SEGMENT_START or ORIGIN) 202 outside of an output section statement, which will be converted from 203 absolute to section-relative in set_sym_sections called from 204 ldexp_finalize_syms after ldemul_finish. */ 205 #define GENERATE_DYNAMIC_RELOCATION_P(IS_X86_64, INFO, EH, R_TYPE, \ 206 SEC, NEED_COPY_RELOC_IN_PIE, \ 207 RESOLVED_TO_ZERO, PC32_RELOC) \ 208 ((bfd_link_pic (INFO) \ 209 && !(bfd_is_abs_section (SEC) \ 210 && ((EH) == NULL \ 211 || (EH)->elf.root.rel_from_abs == 0) \ 212 && ((EH) == NULL \ 213 || SYMBOL_REFERENCES_LOCAL (INFO, &(EH)->elf))) \ 214 && !(NEED_COPY_RELOC_IN_PIE) \ 215 && ((EH) == NULL \ 216 || ((ELF_ST_VISIBILITY ((EH)->elf.other) == STV_DEFAULT \ 217 && (!(RESOLVED_TO_ZERO) || PC32_RELOC)) \ 218 || (EH)->elf.root.type != bfd_link_hash_undefweak)) \ 219 && ((!X86_PCREL_TYPE_P (IS_X86_64, R_TYPE) \ 220 && !X86_SIZE_TYPE_P (IS_X86_64, R_TYPE)) \ 221 || ! SYMBOL_CALLS_LOCAL ((INFO), \ 222 (struct elf_link_hash_entry *) (EH)))) \ 223 || (ELIMINATE_COPY_RELOCS \ 224 && !bfd_link_pic (INFO) \ 225 && (EH) != NULL \ 226 && (EH)->elf.dynindx != -1 \ 227 && (!(EH)->elf.non_got_ref \ 228 || ((EH)->elf.root.type == bfd_link_hash_undefweak \ 229 && !(RESOLVED_TO_ZERO))) \ 230 && (((EH)->elf.def_dynamic && !(EH)->elf.def_regular) \ 231 || (EH)->elf.root.type == bfd_link_hash_undefined))) 232 233 /* TRUE if this input relocation should be copied to output. H->dynindx 234 may be -1 if this symbol was marked to become local. */ 235 #define COPY_INPUT_RELOC_P(IS_X86_64, INFO, H, R_TYPE) \ 236 ((H) != NULL \ 237 && (H)->dynindx != -1 \ 238 && (X86_PCREL_TYPE_P (IS_X86_64, R_TYPE) \ 239 || !(bfd_link_executable (INFO) || SYMBOLIC_BIND ((INFO), (H))) \ 240 || !(H)->def_regular)) 241 242 /* TRUE if this is actually a static link, or it is a -Bsymbolic link 243 and the symbol is defined locally, or the symbol was forced to be 244 local because of a version file. */ 245 #define RESOLVED_LOCALLY_P(INFO, H, HTAB) \ 246 (!WILL_CALL_FINISH_DYNAMIC_SYMBOL ((HTAB)->elf.dynamic_sections_created, \ 247 bfd_link_pic (INFO), (H)) \ 248 || (bfd_link_pic (INFO) \ 249 && SYMBOL_REFERENCES_LOCAL_P ((INFO), (H))) \ 250 || (ELF_ST_VISIBILITY ((H)->other) \ 251 && (H)->root.type == bfd_link_hash_undefweak)) 252 253 /* TRUE if this symbol isn't defined by a shared object. */ 254 #define SYMBOL_DEFINED_NON_SHARED_P(H) \ 255 ((H)->def_regular \ 256 || (H)->root.linker_def \ 257 || (H)->root.ldscript_def \ 258 || ((struct elf_x86_link_hash_entry *) (H))->linker_def \ 259 || ELF_COMMON_DEF_P (H)) 260 261 /* Return TRUE if the symbol described by a linker hash entry H is 262 going to be absolute. Similar to bfd_is_abs_symbol, but excluding 263 all linker-script defined symbols. */ 264 #define ABS_SYMBOL_P(H) \ 265 (bfd_is_abs_symbol (&(H)->root) && !(H)->root.ldscript_def) 266 267 /* TRUE if relative relocation should be generated. GOT reference to 268 global symbol in PIC will lead to dynamic symbol. It becomes a 269 problem when "time" or "times" is defined as a variable in an 270 executable, clashing with functions of the same name in libc. If a 271 symbol isn't undefined weak symbol, don't make it dynamic in PIC and 272 generate relative relocation. Don't generate relative relocation 273 against non-preemptible absolute symbol. */ 274 #define GENERATE_RELATIVE_RELOC_P(INFO, H) \ 275 ((H)->dynindx == -1 \ 276 && !(H)->forced_local \ 277 && (H)->root.type != bfd_link_hash_undefweak \ 278 && bfd_link_pic (INFO) \ 279 && !ABS_SYMBOL_P (H)) 280 281 /* TRUE if this is a pointer reference to a local IFUNC. */ 282 #define POINTER_LOCAL_IFUNC_P(INFO, H) \ 283 ((H)->dynindx == -1 \ 284 || (H)->forced_local \ 285 || bfd_link_executable (INFO)) 286 287 /* TRUE if this is a PLT reference to a local IFUNC. */ 288 #define PLT_LOCAL_IFUNC_P(INFO, H) \ 289 ((H)->dynindx == -1 \ 290 || ((bfd_link_executable (INFO) \ 291 || ELF_ST_VISIBILITY ((H)->other) != STV_DEFAULT) \ 292 && (H)->def_regular \ 293 && (H)->type == STT_GNU_IFUNC)) 294 295 /* TRUE if TLS IE->LE transition is OK. */ 296 #define TLS_TRANSITION_IE_TO_LE_P(INFO, H, TLS_TYPE) \ 297 (bfd_link_executable (INFO) \ 298 && (H) != NULL \ 299 && (H)->dynindx == -1 \ 300 && (TLS_TYPE & GOT_TLS_IE)) 301 302 /* Verify that the symbol has an entry in the procedure linkage table. */ 303 #define VERIFY_PLT_ENTRY(INFO, H, PLT, GOTPLT, RELPLT, LOCAL_UNDEFWEAK) \ 304 do \ 305 { \ 306 if (((H)->dynindx == -1 \ 307 && !LOCAL_UNDEFWEAK \ 308 && !(((H)->forced_local || bfd_link_executable (INFO)) \ 309 && (H)->def_regular \ 310 && (H)->type == STT_GNU_IFUNC)) \ 311 || (PLT) == NULL \ 312 || (GOTPLT) == NULL \ 313 || (RELPLT) == NULL) \ 314 abort (); \ 315 } \ 316 while (0); 317 318 /* Verify that the symbol supports copy relocation. */ 319 #define VERIFY_COPY_RELOC(H, HTAB) \ 320 do \ 321 { \ 322 if ((H)->dynindx == -1 \ 323 || ((H)->root.type != bfd_link_hash_defined \ 324 && (H)->root.type != bfd_link_hash_defweak) \ 325 || (HTAB)->elf.srelbss == NULL \ 326 || (HTAB)->elf.sreldynrelro == NULL) \ 327 abort (); \ 328 } \ 329 while (0); 330 331 /* x86 ELF linker hash entry. */ 332 333 struct elf_x86_link_hash_entry 334 { 335 struct elf_link_hash_entry elf; 336 337 unsigned char tls_type; 338 339 /* Bit 0: Symbol has no GOT nor PLT relocations. 340 Bit 1: Symbol has non-GOT/non-PLT relocations in text sections. 341 zero_undefweak is initialized to 1 and undefined weak symbol 342 should be resolved to 0 if zero_undefweak > 0. */ 343 unsigned int zero_undefweak : 2; 344 345 /* Don't call finish_dynamic_symbol on this symbol. */ 346 unsigned int no_finish_dynamic_symbol : 1; 347 348 /* R_*_RELATIVE relocation in GOT for this symbol has been 349 processed. */ 350 unsigned int got_relative_reloc_done : 1; 351 352 /* TRUE if symbol is __tls_get_addr. */ 353 unsigned int tls_get_addr : 1; 354 355 /* TRUE if symbol is defined as a protected symbol. */ 356 unsigned int def_protected : 1; 357 358 /* 0: Symbol references are unknown. 359 1: Symbol references aren't local. 360 2: Symbol references are local. 361 */ 362 unsigned int local_ref : 2; 363 364 /* TRUE if symbol is defined by linker. */ 365 unsigned int linker_def : 1; 366 367 /* TRUE if symbol is referenced by a non-GOT/non-PLT relocation in a 368 relocatable object file without indirect external access marker. */ 369 unsigned int non_got_ref_without_indirect_extern_access : 1; 370 371 /* TRUE if symbol is referenced by R_386_GOTOFF relocation. This is 372 only used by i386. */ 373 unsigned int gotoff_ref : 1; 374 375 /* TRUE if a weak symbol with a real definition needs a copy reloc. 376 When there is a weak symbol with a real definition, the processor 377 independent code will have arranged for us to see the real 378 definition first. We need to copy the needs_copy bit from the 379 real definition and check it when allowing copy reloc in PIE. This 380 is only used by x86-64. */ 381 unsigned int needs_copy : 1; 382 383 /* Information about the GOT PLT entry. Filled when there are both 384 GOT and PLT relocations against the same function. */ 385 union gotplt_union plt_got; 386 387 /* Information about the second PLT entry. */ 388 union gotplt_union plt_second; 389 390 /* Offset of the GOTPLT entry reserved for the TLS descriptor, 391 starting at the end of the jump table. */ 392 bfd_vma tlsdesc_got; 393 }; 394 395 #define SFRAME_PLT0_MAX_NUM_FRES 2 396 #define SFRAME_PLTN_MAX_NUM_FRES 2 397 398 struct elf_x86_sframe_plt 399 { 400 unsigned int plt0_entry_size; 401 unsigned int plt0_num_fres; 402 const sframe_frame_row_entry *plt0_fres[SFRAME_PLT0_MAX_NUM_FRES]; 403 404 unsigned int pltn_entry_size; 405 unsigned int pltn_num_fres; 406 const sframe_frame_row_entry *pltn_fres[SFRAME_PLTN_MAX_NUM_FRES]; 407 408 unsigned int sec_pltn_entry_size; 409 unsigned int sec_pltn_num_fres; 410 const sframe_frame_row_entry *sec_pltn_fres[SFRAME_PLTN_MAX_NUM_FRES]; 411 }; 412 413 struct elf_x86_lazy_plt_layout 414 { 415 /* The first entry in a lazy procedure linkage table looks like this. */ 416 const bfd_byte *plt0_entry; 417 unsigned int plt0_entry_size; /* Size of PLT0 entry. */ 418 419 /* Later entries in a lazy procedure linkage table look like this. */ 420 const bfd_byte *plt_entry; 421 unsigned int plt_entry_size; /* Size of each PLT entry. */ 422 423 /* The TLSDESC entry in a lazy procedure linkage table looks like 424 this. This is for x86-64 only. */ 425 const bfd_byte *plt_tlsdesc_entry; 426 unsigned int plt_tlsdesc_entry_size; /* Size of TLSDESC entry. */ 427 428 /* Offsets into the TLSDESC entry that are to be replaced with 429 GOT+8 and GOT+TDG. These are for x86-64 only. */ 430 unsigned int plt_tlsdesc_got1_offset; 431 unsigned int plt_tlsdesc_got2_offset; 432 433 /* Offset of the end of the PC-relative instructions containing 434 plt_tlsdesc_got1_offset and plt_tlsdesc_got2_offset. These 435 are for x86-64 only. */ 436 unsigned int plt_tlsdesc_got1_insn_end; 437 unsigned int plt_tlsdesc_got2_insn_end; 438 439 /* Offsets into plt0_entry that are to be replaced with GOT[1] and 440 GOT[2]. */ 441 unsigned int plt0_got1_offset; 442 unsigned int plt0_got2_offset; 443 444 /* Offset of the end of the PC-relative instruction containing 445 plt0_got2_offset. This is for x86-64 only. */ 446 unsigned int plt0_got2_insn_end; 447 448 /* Offsets into plt_entry that are to be replaced with... */ 449 unsigned int plt_got_offset; /* ... address of this symbol in .got. */ 450 unsigned int plt_reloc_offset; /* ... offset into relocation table. */ 451 unsigned int plt_plt_offset; /* ... offset to start of .plt. */ 452 453 /* Length of the PC-relative instruction containing plt_got_offset. 454 This is used for x86-64 only. */ 455 unsigned int plt_got_insn_size; 456 457 /* Offset of the end of the PC-relative jump to plt0_entry. This is 458 used for x86-64 only. */ 459 unsigned int plt_plt_insn_end; 460 461 /* Offset into plt_entry where the initial value of the GOT entry 462 points. */ 463 unsigned int plt_lazy_offset; 464 465 /* The first entry in a PIC lazy procedure linkage table looks like 466 this. */ 467 const bfd_byte *pic_plt0_entry; 468 469 /* Subsequent entries in a PIC lazy procedure linkage table look 470 like this. */ 471 const bfd_byte *pic_plt_entry; 472 473 /* .eh_frame covering the lazy .plt section. */ 474 const bfd_byte *eh_frame_plt; 475 unsigned int eh_frame_plt_size; 476 }; 477 478 struct elf_x86_non_lazy_plt_layout 479 { 480 /* Entries in a non-lazy procedure linkage table look like this. */ 481 const bfd_byte *plt_entry; 482 /* Entries in a PIC non-lazy procedure linkage table look like this. 483 This is only used for i386 where absolute PLT and PIC PLT are 484 different. */ 485 const bfd_byte *pic_plt_entry; 486 487 unsigned int plt_entry_size; /* Size of each PLT entry. */ 488 489 /* Offsets into plt_entry that are to be replaced with... */ 490 unsigned int plt_got_offset; /* ... address of this symbol in .got. */ 491 492 /* Length of the PC-relative instruction containing plt_got_offset. 493 This is used for x86-64 only. */ 494 unsigned int plt_got_insn_size; 495 496 /* .eh_frame covering the non-lazy .plt section. */ 497 const bfd_byte *eh_frame_plt; 498 unsigned int eh_frame_plt_size; 499 }; 500 501 struct elf_x86_plt_layout 502 { 503 /* The first entry in a lazy procedure linkage table looks like this. */ 504 const bfd_byte *plt0_entry; 505 /* Entries in a procedure linkage table look like this. */ 506 const bfd_byte *plt_entry; 507 unsigned int plt_entry_size; /* Size of each PLT entry. */ 508 509 /* 1 has PLT0. */ 510 unsigned int has_plt0; 511 512 /* Offsets into plt_entry that are to be replaced with... */ 513 unsigned int plt_got_offset; /* ... address of this symbol in .got. */ 514 515 /* Length of the PC-relative instruction containing plt_got_offset. 516 This is only used for x86-64. */ 517 unsigned int plt_got_insn_size; 518 519 /* Alignment of the .iplt section. */ 520 unsigned int iplt_alignment; 521 522 /* .eh_frame covering the .plt section. */ 523 const bfd_byte *eh_frame_plt; 524 unsigned int eh_frame_plt_size; 525 }; 526 527 /* Values in tls_type of x86 ELF linker hash entry. */ 528 #define GOT_UNKNOWN 0 529 #define GOT_NORMAL 1 530 #define GOT_TLS_GD 2 531 #define GOT_TLS_IE 4 532 #define GOT_TLS_IE_POS 5 533 #define GOT_TLS_IE_NEG 6 534 #define GOT_TLS_IE_BOTH 7 535 #define GOT_TLS_GDESC 8 536 #define GOT_ABS 9 537 #define GOT_TLS_GD_BOTH_P(type) \ 538 ((type) == (GOT_TLS_GD | GOT_TLS_GDESC)) 539 #define GOT_TLS_GD_P(type) \ 540 ((type) == GOT_TLS_GD || GOT_TLS_GD_BOTH_P (type)) 541 #define GOT_TLS_GDESC_P(type) \ 542 ((type) == GOT_TLS_GDESC || GOT_TLS_GD_BOTH_P (type)) 543 #define GOT_TLS_GD_ANY_P(type) \ 544 (GOT_TLS_GD_P (type) || GOT_TLS_GDESC_P (type)) 545 546 #define elf_x86_hash_entry(ent) \ 547 ((struct elf_x86_link_hash_entry *)(ent)) 548 549 /* Information of an input relocation used to compute its contribution 550 to the DT_RELR section size. */ 551 552 struct elf_x86_relative_reloc_record 553 { 554 /* The original relocation info. */ 555 Elf_Internal_Rela rel; 556 /* The input or the GOT section where the relocation is applied. */ 557 asection *sec; 558 /* Local symbol info. NULL for global symbol. */ 559 Elf_Internal_Sym *sym; 560 union 561 { 562 /* Section where the local symbol is defined. */ 563 asection *sym_sec; 564 /* Global symbol hash. */ 565 struct elf_link_hash_entry *h; 566 } u; 567 /* The offset into the output section where the relative relocation 568 will be applied at run-time. */ 569 bfd_vma offset; 570 /* The run-time address. */ 571 bfd_vma address; 572 }; 573 574 struct elf_x86_relative_reloc_data 575 { 576 bfd_size_type count; 577 bfd_size_type size; 578 struct elf_x86_relative_reloc_record *data; 579 }; 580 581 /* DT_RELR bitmap. */ 582 struct elf_dt_relr_bitmap 583 { 584 bfd_size_type count; 585 bfd_size_type size; 586 union 587 { 588 /* 32-bit bitmap. */ 589 uint32_t *elf32; 590 /* 64-bit bitmap. */ 591 uint64_t *elf64; 592 } u; 593 }; 594 595 /* x86 ELF linker hash table. */ 596 597 struct elf_x86_link_hash_table 598 { 599 struct elf_link_hash_table elf; 600 601 /* Short-cuts to get to dynamic linker sections. */ 602 asection *interp; 603 asection *plt_eh_frame; 604 asection *plt_second; 605 asection *plt_second_eh_frame; 606 asection *plt_got; 607 asection *plt_got_eh_frame; 608 609 sframe_encoder_ctx *plt_cfe_ctx; 610 asection *plt_sframe; 611 sframe_encoder_ctx *plt_second_cfe_ctx; 612 asection *plt_second_sframe; 613 614 /* Parameters describing PLT generation, lazy or non-lazy. */ 615 struct elf_x86_plt_layout plt; 616 617 /* Parameters describing lazy PLT generation. */ 618 const struct elf_x86_lazy_plt_layout *lazy_plt; 619 620 /* Parameters describing non-lazy PLT generation. */ 621 const struct elf_x86_non_lazy_plt_layout *non_lazy_plt; 622 623 /* The .sframe helper object for .plt section. 624 This is used for x86-64 only. */ 625 const struct elf_x86_sframe_plt *sframe_plt; 626 627 union 628 { 629 bfd_signed_vma refcount; 630 bfd_vma offset; 631 } tls_ld_or_ldm_got; 632 633 /* The amount of space used by the jump slots in the GOT. */ 634 bfd_vma sgotplt_jump_table_size; 635 636 /* _TLS_MODULE_BASE_ symbol. */ 637 struct bfd_link_hash_entry *tls_module_base; 638 639 /* Used by local STT_GNU_IFUNC symbols. */ 640 htab_t loc_hash_table; 641 void * loc_hash_memory; 642 643 /* The index of the next R_X86_64_JUMP_SLOT entry in .rela.plt. */ 644 bfd_vma next_jump_slot_index; 645 /* The index of the next R_X86_64_IRELATIVE entry in .rela.plt. */ 646 bfd_vma next_irelative_index; 647 648 /* The (unloaded but important) .rel.plt.unloaded section on VxWorks. 649 This is used for i386 only. */ 650 asection *srelplt2; 651 652 /* The index of the next unused R_386_TLS_DESC slot in .rel.plt. This 653 is only used for i386. */ 654 bfd_vma next_tls_desc_index; 655 656 /* DT_RELR bitmap. */ 657 struct elf_dt_relr_bitmap dt_relr_bitmap; 658 659 /* Relative relocation data. */ 660 struct elf_x86_relative_reloc_data relative_reloc; 661 662 /* Unaligned relative relocation data. */ 663 struct elf_x86_relative_reloc_data unaligned_relative_reloc; 664 665 /* Number of relative reloc generation pass. */ 666 unsigned int generate_relative_reloc_pass; 667 668 /* Value used to fill the unused bytes of the first PLT entry. This 669 is only used for i386. */ 670 bfd_byte plt0_pad_byte; 671 672 /* TRUE if GOT is referenced. */ 673 unsigned int got_referenced : 1; 674 675 /* TRUE if PLT is PC-relative. PLT in PDE and PC-relative PLT in PIE 676 can be used as function address. 677 678 NB: i386 has non-PIC PLT and PIC PLT. Only non-PIC PLT in PDE can 679 be used as function address. PIC PLT in PIE can't be used as 680 function address. */ 681 unsigned int pcrel_plt : 1; 682 683 bfd_vma (*r_info) (bfd_vma, bfd_vma); 684 bfd_vma (*r_sym) (bfd_vma); 685 bool (*is_reloc_section) (const char *); 686 unsigned int sizeof_reloc; 687 unsigned int got_entry_size; 688 unsigned int pointer_r_type; 689 unsigned int relative_r_type; 690 int dynamic_interpreter_size; 691 const char *dynamic_interpreter; 692 const char *tls_get_addr; 693 const char *relative_r_name; 694 void (*elf_append_reloc) (bfd *, asection *, Elf_Internal_Rela *); 695 void (*elf_write_addend) (bfd *, uint64_t, void *); 696 void (*elf_write_addend_in_got) (bfd *, uint64_t, void *); 697 698 /* Options passed from the linker. */ 699 struct elf_linker_x86_params *params; 700 }; 701 702 struct elf_x86_init_table 703 { 704 /* The lazy PLT layout. */ 705 const struct elf_x86_lazy_plt_layout *lazy_plt; 706 707 /* The non-lazy PLT layout. */ 708 const struct elf_x86_non_lazy_plt_layout *non_lazy_plt; 709 710 /* The lazy PLT layout for IBT. */ 711 const struct elf_x86_lazy_plt_layout *lazy_ibt_plt; 712 713 /* The non-lazy PLT layout for IBT. */ 714 const struct elf_x86_non_lazy_plt_layout *non_lazy_ibt_plt; 715 716 /* The .sframe helper object for lazy .plt section. 717 This is used for x86-64 only. */ 718 const struct elf_x86_sframe_plt *sframe_lazy_plt; 719 720 /* The .sframe helper object for non-lazy .plt section. 721 This is used for x86-64 only. */ 722 const struct elf_x86_sframe_plt *sframe_non_lazy_plt; 723 724 /* The .sframe helper object for lazy IBT .plt section. 725 This is used for x86-64 only. */ 726 const struct elf_x86_sframe_plt *sframe_lazy_ibt_plt; 727 728 /* The .sframe helper object for non-lazy IBT .plt section. 729 This is used for x86-64 only. */ 730 const struct elf_x86_sframe_plt *sframe_non_lazy_ibt_plt; 731 732 bfd_byte plt0_pad_byte; 733 734 bfd_vma (*r_info) (bfd_vma, bfd_vma); 735 bfd_vma (*r_sym) (bfd_vma); 736 }; 737 738 struct elf_x86_obj_tdata 739 { 740 struct elf_obj_tdata root; 741 742 /* tls_type for each local got entry. */ 743 char *local_got_tls_type; 744 745 /* GOTPLT entries for TLS descriptors. */ 746 bfd_vma *local_tlsdesc_gotent; 747 748 /* R_*_RELATIVE relocation in GOT for this local symbol has been 749 processed. */ 750 char *relative_reloc_done; 751 }; 752 753 enum elf_x86_plt_type 754 { 755 plt_non_lazy = 0, 756 plt_lazy = 1 << 0, 757 plt_pic = 1 << 1, 758 plt_second = 1 << 2, 759 plt_unknown = -1 760 }; 761 762 struct elf_x86_plt 763 { 764 const char *name; 765 asection *sec; 766 bfd_byte *contents; 767 enum elf_x86_plt_type type; 768 unsigned int plt_got_offset; 769 unsigned int plt_entry_size; 770 unsigned int plt_got_insn_size; /* Only used for x86-64. */ 771 long count; 772 }; 773 774 /* Set if a relocation is converted from a GOTPCREL relocation. */ 775 #define R_X86_64_converted_reloc_bit (1 << 7) 776 777 #define elf_x86_tdata(abfd) \ 778 ((struct elf_x86_obj_tdata *) (abfd)->tdata.any) 779 780 #define elf_x86_local_got_tls_type(abfd) \ 781 (elf_x86_tdata (abfd)->local_got_tls_type) 782 783 #define elf_x86_local_tlsdesc_gotent(abfd) \ 784 (elf_x86_tdata (abfd)->local_tlsdesc_gotent) 785 786 #define elf_x86_relative_reloc_done(abfd) \ 787 (elf_x86_tdata (abfd)->relative_reloc_done) 788 789 #define elf_x86_compute_jump_table_size(htab) \ 790 ((htab)->elf.srelplt->reloc_count * (htab)->got_entry_size) 791 792 #define is_x86_elf(bfd, htab) \ 793 (bfd_get_flavour (bfd) == bfd_target_elf_flavour \ 794 && elf_tdata (bfd) != NULL \ 795 && elf_object_id (bfd) == (htab)->elf.hash_table_id) 796 797 /* Rename some of the generic section flags to better document how they 798 are used here. */ 799 #define check_relocs_failed sec_flg0 800 #define relative_reloc_packed sec_flg1 801 802 extern bool _bfd_x86_elf_mkobject 803 (bfd *); 804 805 extern void _bfd_x86_elf_set_tls_module_base 806 (struct bfd_link_info *); 807 808 extern bfd_vma _bfd_x86_elf_dtpoff_base 809 (struct bfd_link_info *); 810 811 extern bool _bfd_x86_elf_readonly_dynrelocs 812 (struct elf_link_hash_entry *, void *); 813 814 extern struct elf_link_hash_entry * _bfd_elf_x86_get_local_sym_hash 815 (struct elf_x86_link_hash_table *, bfd *, const Elf_Internal_Rela *, 816 bool); 817 818 extern hashval_t _bfd_x86_elf_local_htab_hash 819 (const void *); 820 821 extern int _bfd_x86_elf_local_htab_eq 822 (const void *, const void *); 823 824 extern struct bfd_hash_entry * _bfd_x86_elf_link_hash_newfunc 825 (struct bfd_hash_entry *, struct bfd_hash_table *, const char *); 826 827 extern struct bfd_link_hash_table * _bfd_x86_elf_link_hash_table_create 828 (bfd *); 829 830 extern int _bfd_x86_elf_compare_relocs 831 (const void *, const void *); 832 833 extern bool _bfd_x86_elf_link_check_relocs 834 (bfd *, struct bfd_link_info *); 835 836 extern bool _bfd_x86_elf_check_relocs 837 (bfd *, struct bfd_link_info *, asection *, 838 const Elf_Internal_Rela *); 839 840 extern bool _bfd_x86_elf_link_relax_section 841 (bfd *, asection *, struct bfd_link_info *, bool *); 842 843 extern bool _bfd_elf_x86_size_relative_relocs 844 (struct bfd_link_info *, bool *); 845 846 extern bool _bfd_elf_x86_finish_relative_relocs 847 (struct bfd_link_info *); 848 849 extern void _bfd_elf32_write_addend (bfd *, uint64_t, void *); 850 extern void _bfd_elf64_write_addend (bfd *, uint64_t, void *); 851 852 extern bool _bfd_elf_x86_valid_reloc_p 853 (asection *, struct bfd_link_info *, struct elf_x86_link_hash_table *, 854 const Elf_Internal_Rela *, struct elf_link_hash_entry *, 855 Elf_Internal_Sym *, Elf_Internal_Shdr *, bool *); 856 857 extern bool _bfd_x86_elf_size_dynamic_sections 858 (bfd *, struct bfd_link_info *); 859 860 extern struct elf_x86_link_hash_table *_bfd_x86_elf_finish_dynamic_sections 861 (bfd *, struct bfd_link_info *); 862 863 extern bool _bfd_x86_elf_always_size_sections 864 (bfd *, struct bfd_link_info *); 865 866 extern void _bfd_x86_elf_merge_symbol_attribute 867 (struct elf_link_hash_entry *, unsigned int, bool, bool); 868 869 extern void _bfd_x86_elf_copy_indirect_symbol 870 (struct bfd_link_info *, struct elf_link_hash_entry *, 871 struct elf_link_hash_entry *); 872 873 extern bool _bfd_x86_elf_fixup_symbol 874 (struct bfd_link_info *, struct elf_link_hash_entry *); 875 876 extern bool _bfd_x86_elf_hash_symbol 877 (struct elf_link_hash_entry *); 878 879 extern bool _bfd_x86_elf_adjust_dynamic_symbol 880 (struct bfd_link_info *, struct elf_link_hash_entry *); 881 882 extern void _bfd_x86_elf_hide_symbol 883 (struct bfd_link_info *, struct elf_link_hash_entry *, bool); 884 885 extern bool _bfd_x86_elf_link_symbol_references_local 886 (struct bfd_link_info *, struct elf_link_hash_entry *); 887 888 extern asection * _bfd_x86_elf_gc_mark_hook 889 (asection *, struct bfd_link_info *, Elf_Internal_Rela *, 890 struct elf_link_hash_entry *, Elf_Internal_Sym *); 891 892 extern long _bfd_x86_elf_get_synthetic_symtab 893 (bfd *, long, long, bfd_vma, struct elf_x86_plt [], asymbol **, 894 asymbol **); 895 896 extern enum elf_property_kind _bfd_x86_elf_parse_gnu_properties 897 (bfd *, unsigned int, bfd_byte *, unsigned int); 898 899 extern bool _bfd_x86_elf_merge_gnu_properties 900 (struct bfd_link_info *, bfd *, bfd *, elf_property *, elf_property *); 901 902 extern void _bfd_x86_elf_link_fixup_gnu_properties 903 (struct bfd_link_info *, elf_property_list **); 904 905 extern bfd * _bfd_x86_elf_link_setup_gnu_properties 906 (struct bfd_link_info *, struct elf_x86_init_table *); 907 908 extern void _bfd_x86_elf_link_fixup_ifunc_symbol 909 (struct bfd_link_info *, struct elf_x86_link_hash_table *, 910 struct elf_link_hash_entry *, Elf_Internal_Sym *sym); 911 912 extern void _bfd_x86_elf_link_report_relative_reloc 913 (struct bfd_link_info *, asection *, struct elf_link_hash_entry *, 914 Elf_Internal_Sym *, const char *, const void *); 915 916 #define bfd_elf64_mkobject \ 917 _bfd_x86_elf_mkobject 918 #define bfd_elf32_mkobject \ 919 _bfd_x86_elf_mkobject 920 #define bfd_elf64_bfd_link_hash_table_create \ 921 _bfd_x86_elf_link_hash_table_create 922 #define bfd_elf32_bfd_link_hash_table_create \ 923 _bfd_x86_elf_link_hash_table_create 924 #define bfd_elf64_bfd_link_check_relocs \ 925 _bfd_x86_elf_link_check_relocs 926 #define bfd_elf32_bfd_link_check_relocs \ 927 _bfd_x86_elf_link_check_relocs 928 #define bfd_elf32_bfd_relax_section \ 929 _bfd_x86_elf_link_relax_section 930 #define bfd_elf64_bfd_relax_section \ 931 _bfd_x86_elf_link_relax_section 932 933 #define elf_backend_check_relocs \ 934 _bfd_x86_elf_check_relocs 935 #define elf_backend_size_dynamic_sections \ 936 _bfd_x86_elf_size_dynamic_sections 937 #define elf_backend_merge_symbol_attribute \ 938 _bfd_x86_elf_merge_symbol_attribute 939 #define elf_backend_copy_indirect_symbol \ 940 _bfd_x86_elf_copy_indirect_symbol 941 #define elf_backend_fixup_symbol \ 942 _bfd_x86_elf_fixup_symbol 943 #define elf_backend_hash_symbol \ 944 _bfd_x86_elf_hash_symbol 945 #define elf_backend_adjust_dynamic_symbol \ 946 _bfd_x86_elf_adjust_dynamic_symbol 947 #define elf_backend_gc_mark_hook \ 948 _bfd_x86_elf_gc_mark_hook 949 #define elf_backend_omit_section_dynsym \ 950 _bfd_elf_omit_section_dynsym_all 951 #define elf_backend_parse_gnu_properties \ 952 _bfd_x86_elf_parse_gnu_properties 953 #define elf_backend_merge_gnu_properties \ 954 _bfd_x86_elf_merge_gnu_properties 955 #define elf_backend_fixup_gnu_properties \ 956 _bfd_x86_elf_link_fixup_gnu_properties 957 #define elf_backend_size_relative_relocs \ 958 _bfd_elf_x86_size_relative_relocs 959 #define elf_backend_finish_relative_relocs \ 960 _bfd_elf_x86_finish_relative_relocs 961 962 #define ELF_P_ALIGN ELF_MINPAGESIZE 963 964 /* Allocate x86 GOT info for local symbols. */ 965 966 static inline bool 967 elf_x86_allocate_local_got_info (bfd *abfd, bfd_size_type count) 968 { 969 bfd_signed_vma *local_got_refcounts = elf_local_got_refcounts (abfd); 970 if (local_got_refcounts == NULL) 971 { 972 bfd_size_type size = count * (sizeof (bfd_signed_vma) 973 + sizeof (bfd_vma) 974 + 2 * sizeof(char)); 975 local_got_refcounts = (bfd_signed_vma *) bfd_zalloc (abfd, size); 976 if (local_got_refcounts == NULL) 977 return false; 978 elf_local_got_refcounts (abfd) = local_got_refcounts; 979 elf_x86_local_tlsdesc_gotent (abfd) = 980 (bfd_vma *) (local_got_refcounts + count); 981 elf_x86_local_got_tls_type (abfd) = 982 (char *) (local_got_refcounts + 2 * count); 983 elf_x86_relative_reloc_done (abfd) = 984 ((char *) (local_got_refcounts + 2 * count)) + count; 985 } 986 return true; 987 } 988