1 /* `a.out' object-file definitions, including extensions to 64-bit fields 2 3 Copyright (C) 1999-2021 Free Software Foundation, Inc. 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program; if not, write to the Free Software 17 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 18 MA 02110-1301, USA. */ 19 20 #ifndef __A_OUT_64_H__ 21 #define __A_OUT_64_H__ 22 23 #ifndef BYTES_IN_WORD 24 #define BYTES_IN_WORD 4 25 #endif 26 27 /* This is the layout on disk of the 32-bit or 64-bit exec header. */ 28 29 #ifndef external_exec 30 struct external_exec 31 { 32 bfd_byte e_info[4]; /* Magic number and stuff. */ 33 bfd_byte e_text[BYTES_IN_WORD]; /* Length of text section in bytes. */ 34 bfd_byte e_data[BYTES_IN_WORD]; /* Length of data section in bytes. */ 35 bfd_byte e_bss[BYTES_IN_WORD]; /* Length of bss area in bytes. */ 36 bfd_byte e_syms[BYTES_IN_WORD]; /* Length of symbol table in bytes. */ 37 bfd_byte e_entry[BYTES_IN_WORD]; /* Start address. */ 38 bfd_byte e_trsize[BYTES_IN_WORD]; /* Length of text relocation info. */ 39 bfd_byte e_drsize[BYTES_IN_WORD]; /* Length of data relocation info. */ 40 }; 41 42 #define EXEC_BYTES_SIZE (4 + BYTES_IN_WORD * 7) 43 44 /* Magic numbers for a.out files. */ 45 46 #if ARCH_SIZE==64 47 #define OMAGIC 0x1001 /* Code indicating object file. */ 48 #define ZMAGIC 0x1002 /* Code indicating demand-paged executable. */ 49 #define NMAGIC 0x1003 /* Code indicating pure executable. */ 50 51 /* There is no 64-bit QMAGIC as far as I know. */ 52 53 #define N_BADMAG(x) (N_MAGIC(x) != OMAGIC \ 54 && N_MAGIC(x) != NMAGIC \ 55 && N_MAGIC(x) != ZMAGIC) 56 #else 57 #define OMAGIC 0407 /* Object file or impure executable. */ 58 #define NMAGIC 0410 /* Code indicating pure executable. */ 59 #define IMAGIC 0411 /* Separate instruction & data spaces for PDP-11. */ 60 #define ZMAGIC 0413 /* Code indicating demand-paged executable. */ 61 #define BMAGIC 0415 /* Used by a b.out object. */ 62 63 /* This indicates a demand-paged executable with the header in the text. 64 It is used by 386BSD (and variants) and Linux, at least. */ 65 #ifndef QMAGIC 66 #define QMAGIC 0314 67 #endif 68 # ifndef N_BADMAG 69 # define N_BADMAG(x) (N_MAGIC(x) != OMAGIC \ 70 && N_MAGIC(x) != NMAGIC \ 71 && N_MAGIC(x) != ZMAGIC \ 72 && N_MAGIC(x) != QMAGIC) 73 # endif /* N_BADMAG */ 74 #endif 75 76 #endif 77 78 #ifdef QMAGIC 79 #define N_IS_QMAGIC(x) (N_MAGIC (x) == QMAGIC) 80 #else 81 #define N_IS_QMAGIC(x) (0) 82 #endif 83 84 /* The difference between TARGET_PAGE_SIZE and N_SEGSIZE is that TARGET_PAGE_SIZE is 85 the finest granularity at which you can page something, thus it 86 controls the padding (if any) before the text segment of a ZMAGIC 87 file. N_SEGSIZE is the resolution at which things can be marked as 88 read-only versus read/write, so it controls the padding between the 89 text segment and the data segment (in memory; on disk the padding 90 between them is TARGET_PAGE_SIZE). TARGET_PAGE_SIZE and N_SEGSIZE are the same 91 for most machines, but different for sun3. */ 92 93 /* By default, segment size is constant. But some machines override this 94 to be a function of the a.out header (e.g. machine type). */ 95 96 #ifndef N_SEGSIZE 97 #define N_SEGSIZE(x) SEGMENT_SIZE 98 #endif 99 100 /* Virtual memory address of the text section. 101 This is getting very complicated. A good reason to discard a.out format 102 for something that specifies these fields explicitly. But til then... 103 104 * OMAGIC and NMAGIC files: 105 (object files: text for "relocatable addr 0" right after the header) 106 start at 0, offset is EXEC_BYTES_SIZE, size as stated. 107 * The text address, offset, and size of ZMAGIC files depend 108 on the entry point of the file: 109 * entry point below TEXT_START_ADDR: 110 (hack for SunOS shared libraries) 111 start at 0, offset is 0, size as stated. 112 * If N_HEADER_IN_TEXT(x) is true (which defaults to being the 113 case when the entry point is EXEC_BYTES_SIZE or further into a page): 114 no padding is needed; text can start after exec header. Sun 115 considers the text segment of such files to include the exec header; 116 for BFD's purposes, we don't, which makes more work for us. 117 start at TEXT_START_ADDR + EXEC_BYTES_SIZE, offset is EXEC_BYTES_SIZE, 118 size as stated minus EXEC_BYTES_SIZE. 119 * If N_HEADER_IN_TEXT(x) is false (which defaults to being the case when 120 the entry point is less than EXEC_BYTES_SIZE into a page (e.g. page 121 aligned)): (padding is needed so that text can start at a page boundary) 122 start at TEXT_START_ADDR, offset TARGET_PAGE_SIZE, size as stated. 123 124 Specific configurations may want to hardwire N_HEADER_IN_TEXT, 125 for efficiency or to allow people to play games with the entry point. 126 In that case, you would #define N_HEADER_IN_TEXT(x) as 1 for sunos, 127 and as 0 for most other hosts (Sony News, Vax Ultrix, etc). 128 (Do this in the appropriate bfd target file.) 129 (The default is a heuristic that will break if people try changing 130 the entry point, perhaps with the ld -e flag.) 131 132 * QMAGIC is always like a ZMAGIC for which N_HEADER_IN_TEXT is true, 133 and for which the starting address is TARGET_PAGE_SIZE (or should this be 134 SEGMENT_SIZE?) (TEXT_START_ADDR only applies to ZMAGIC, not to QMAGIC). */ 135 136 /* This macro is only relevant for ZMAGIC files; QMAGIC always has the header 137 in the text. */ 138 #ifndef N_HEADER_IN_TEXT 139 #define N_HEADER_IN_TEXT(x) \ 140 (((x)->a_entry & (TARGET_PAGE_SIZE-1)) >= EXEC_BYTES_SIZE) 141 #endif 142 143 /* Sun shared libraries, not linux. This macro is only relevant for ZMAGIC 144 files. */ 145 #ifndef N_SHARED_LIB 146 #define N_SHARED_LIB(x) (0) 147 #endif 148 149 /* Returning 0 not TEXT_START_ADDR for OMAGIC and NMAGIC is based on 150 the assumption that we are dealing with a .o file, not an 151 executable. This is necessary for OMAGIC (but means we don't work 152 right on the output from ld -N); more questionable for NMAGIC. */ 153 154 #ifndef N_TXTADDR 155 #define N_TXTADDR(x) \ 156 (/* The address of a QMAGIC file is always one page in, \ 157 with the header in the text. */ \ 158 N_IS_QMAGIC (x) \ 159 ? (bfd_vma) TARGET_PAGE_SIZE + EXEC_BYTES_SIZE \ 160 : (N_MAGIC (x) != ZMAGIC \ 161 ? (bfd_vma) 0 /* Object file or NMAGIC. */ \ 162 : (N_SHARED_LIB (x) \ 163 ? (bfd_vma) 0 \ 164 : (N_HEADER_IN_TEXT (x) \ 165 ? (bfd_vma) TEXT_START_ADDR + EXEC_BYTES_SIZE \ 166 : (bfd_vma) TEXT_START_ADDR)))) 167 #endif 168 169 /* If N_HEADER_IN_TEXT is not true for ZMAGIC, there is some padding 170 to make the text segment start at a certain boundary. For most 171 systems, this boundary is TARGET_PAGE_SIZE. But for Linux, in the 172 time-honored tradition of crazy ZMAGIC hacks, it is 1024 which is 173 not what TARGET_PAGE_SIZE needs to be for QMAGIC. */ 174 175 #ifndef ZMAGIC_DISK_BLOCK_SIZE 176 #define ZMAGIC_DISK_BLOCK_SIZE TARGET_PAGE_SIZE 177 #endif 178 179 #define N_DISK_BLOCK_SIZE(x) \ 180 (N_MAGIC(x) == ZMAGIC ? ZMAGIC_DISK_BLOCK_SIZE : TARGET_PAGE_SIZE) 181 182 /* Offset in an a.out of the start of the text section. */ 183 #ifndef N_TXTOFF 184 #define N_TXTOFF(x) \ 185 (/* For {O,N,Q}MAGIC, no padding. */ \ 186 N_MAGIC (x) != ZMAGIC \ 187 ? EXEC_BYTES_SIZE \ 188 : (N_SHARED_LIB (x) \ 189 ? 0 \ 190 : (N_HEADER_IN_TEXT (x) \ 191 ? EXEC_BYTES_SIZE /* No padding. */ \ 192 : ZMAGIC_DISK_BLOCK_SIZE /* A page of padding. */))) 193 #endif 194 /* Size of the text section. It's always as stated, except that we 195 offset it to `undo' the adjustment to N_TXTADDR and N_TXTOFF 196 for ZMAGIC files that nominally include the exec header 197 as part of the first page of text. (BFD doesn't consider the 198 exec header to be part of the text segment.) */ 199 #ifndef N_TXTSIZE 200 #define N_TXTSIZE(x) \ 201 (/* For QMAGIC, we don't consider the header part of the text section. */\ 202 N_IS_QMAGIC (x) \ 203 ? (x)->a_text - EXEC_BYTES_SIZE \ 204 : ((N_MAGIC (x) != ZMAGIC || N_SHARED_LIB (x)) \ 205 ? (x)->a_text \ 206 : (N_HEADER_IN_TEXT (x) \ 207 ? (x)->a_text - EXEC_BYTES_SIZE /* No padding. */ \ 208 : (x)->a_text /* A page of padding. */ ))) 209 #endif 210 /* The address of the data segment in virtual memory. 211 It is the text segment address, plus text segment size, rounded 212 up to a N_SEGSIZE boundary for pure or pageable files. */ 213 #ifndef N_DATADDR 214 #define N_DATADDR(x) \ 215 (N_MAGIC (x) == IMAGIC \ 216 ? (bfd_vma) 0 \ 217 : N_MAGIC (x) == OMAGIC \ 218 ? (N_TXTADDR (x) + N_TXTSIZE (x)) \ 219 : (N_SEGSIZE (x) + ((N_TXTADDR (x) + N_TXTSIZE (x) - 1) \ 220 & ~ (bfd_vma) (N_SEGSIZE (x) - 1)))) 221 #endif 222 /* The address of the BSS segment -- immediately after the data segment. */ 223 224 #define N_BSSADDR(x) (N_DATADDR (x) + (x)->a_data) 225 226 /* Offsets of the various portions of the file after the text segment. */ 227 228 /* For {Q,Z}MAGIC, there is padding to make the data segment start on 229 a page boundary. Most of the time the a_text field (and thus 230 N_TXTSIZE) already contains this padding. It is possible that for 231 BSDI and/or 386BSD it sometimes doesn't contain the padding, and 232 perhaps we should be adding it here. But this seems kind of 233 questionable and probably should be BSDI/386BSD-specific if we do 234 do it. 235 236 For NMAGIC (at least for hp300 BSD, probably others), there is 237 padding in memory only, not on disk, so we must *not* ever pad here 238 for NMAGIC. */ 239 240 #ifndef N_DATOFF 241 #define N_DATOFF(x) (N_TXTOFF (x) + N_TXTSIZE (x)) 242 #endif 243 #ifndef N_TRELOFF 244 #define N_TRELOFF(x) (N_DATOFF (x) + (x)->a_data) 245 #endif 246 #ifndef N_DRELOFF 247 #define N_DRELOFF(x) (N_TRELOFF (x) + (x)->a_trsize) 248 #endif 249 #ifndef N_SYMOFF 250 #define N_SYMOFF(x) (N_DRELOFF (x) + (x)->a_drsize) 251 #endif 252 #ifndef N_STROFF 253 #define N_STROFF(x) (N_SYMOFF (x) + (x)->a_syms) 254 #endif 255 256 /* Symbols */ 257 #ifndef external_nlist 258 struct external_nlist 259 { 260 bfd_byte e_strx[BYTES_IN_WORD]; /* Index into string table of name. */ 261 bfd_byte e_type[1]; /* Type of symbol. */ 262 bfd_byte e_other[1]; /* Misc info (usually empty). */ 263 bfd_byte e_desc[2]; /* Description field. */ 264 bfd_byte e_value[BYTES_IN_WORD]; /* Value of symbol. */ 265 }; 266 #define EXTERNAL_NLIST_SIZE (BYTES_IN_WORD+4+BYTES_IN_WORD) 267 #endif 268 269 struct internal_nlist 270 { 271 unsigned long n_strx; /* Index into string table of name. */ 272 unsigned char n_type; /* Type of symbol. */ 273 unsigned char n_other; /* Misc info (usually empty). */ 274 unsigned short n_desc; /* Description field. */ 275 bfd_vma n_value; /* Value of symbol. */ 276 }; 277 278 /* The n_type field is the symbol type, containing: */ 279 280 #define N_UNDF 0 /* Undefined symbol. */ 281 #define N_ABS 2 /* Absolute symbol -- defined at particular addr. */ 282 #define N_TEXT 4 /* Text sym -- defined at offset in text seg. */ 283 #define N_DATA 6 /* Data sym -- defined at offset in data seg. */ 284 #define N_BSS 8 /* BSS sym -- defined at offset in zero'd seg. */ 285 #define N_COMM 0x12 /* Common symbol (visible after shared lib dynlink). */ 286 #define N_FN 0x1f /* File name of .o file. */ 287 #define N_FN_SEQ 0x0C /* N_FN from Sequent compilers (sigh). */ 288 /* Note: N_EXT can only be usefully OR-ed with N_UNDF, N_ABS, N_TEXT, 289 N_DATA, or N_BSS. When the low-order bit of other types is set, 290 (e.g. N_WARNING versus N_FN), they are two different types. */ 291 #define N_EXT 1 /* External symbol (as opposed to local-to-this-file). */ 292 #define N_TYPE 0x1e 293 #define N_STAB 0xe0 /* If any of these bits are on, it's a debug symbol. */ 294 295 #define N_INDR 0x0a 296 297 /* The following symbols refer to set elements. 298 All the N_SET[ATDB] symbols with the same name form one set. 299 Space is allocated for the set in the text section, and each set 300 elements value is stored into one word of the space. 301 The first word of the space is the length of the set (number of elements). 302 303 The address of the set is made into an N_SETV symbol 304 whose name is the same as the name of the set. 305 This symbol acts like a N_DATA global symbol 306 in that it can satisfy undefined external references. */ 307 308 /* These appear as input to LD, in a .o file. */ 309 #define N_SETA 0x14 /* Absolute set element symbol. */ 310 #define N_SETT 0x16 /* Text set element symbol. */ 311 #define N_SETD 0x18 /* Data set element symbol. */ 312 #define N_SETB 0x1A /* Bss set element symbol. */ 313 314 /* This is output from LD. */ 315 #define N_SETV 0x1C /* Pointer to set vector in data area. */ 316 317 /* Warning symbol. The text gives a warning message, the next symbol 318 in the table will be undefined. When the symbol is referenced, the 319 message is printed. */ 320 321 #define N_WARNING 0x1e 322 323 /* Weak symbols. These are a GNU extension to the a.out format. The 324 semantics are those of ELF weak symbols. Weak symbols are always 325 externally visible. The N_WEAK? values are squeezed into the 326 available slots. The value of a N_WEAKU symbol is 0. The values 327 of the other types are the definitions. */ 328 #define N_WEAKU 0x0d /* Weak undefined symbol. */ 329 #define N_WEAKA 0x0e /* Weak absolute symbol. */ 330 #define N_WEAKT 0x0f /* Weak text symbol. */ 331 #define N_WEAKD 0x10 /* Weak data symbol. */ 332 #define N_WEAKB 0x11 /* Weak bss symbol. */ 333 334 /* Relocations 335 336 There are two types of relocation flavours for a.out systems, 337 standard and extended. The standard form is used on systems where the 338 instruction has room for all the bits of an offset to the operand, whilst 339 the extended form is used when an address operand has to be split over n 340 instructions. Eg, on the 68k, each move instruction can reference 341 the target with a displacement of 16 or 32 bits. On the sparc, move 342 instructions use an offset of 14 bits, so the offset is stored in 343 the reloc field, and the data in the section is ignored. */ 344 345 /* This structure describes a single relocation to be performed. 346 The text-relocation section of the file is a vector of these structures, 347 all of which apply to the text section. 348 Likewise, the data-relocation section applies to the data section. */ 349 350 struct reloc_std_external 351 { 352 bfd_byte r_address[BYTES_IN_WORD]; /* Offset of data to relocate. */ 353 bfd_byte r_index[3]; /* Symbol table index of symbol. */ 354 bfd_byte r_type[1]; /* Relocation type. */ 355 }; 356 357 #define RELOC_STD_BITS_PCREL_BIG ((unsigned int) 0x80) 358 #define RELOC_STD_BITS_PCREL_LITTLE ((unsigned int) 0x01) 359 360 #define RELOC_STD_BITS_LENGTH_BIG ((unsigned int) 0x60) 361 #define RELOC_STD_BITS_LENGTH_SH_BIG 5 362 #define RELOC_STD_BITS_LENGTH_LITTLE ((unsigned int) 0x06) 363 #define RELOC_STD_BITS_LENGTH_SH_LITTLE 1 364 365 #define RELOC_STD_BITS_EXTERN_BIG ((unsigned int) 0x10) 366 #define RELOC_STD_BITS_EXTERN_LITTLE ((unsigned int) 0x08) 367 368 #define RELOC_STD_BITS_BASEREL_BIG ((unsigned int) 0x08) 369 #define RELOC_STD_BITS_BASEREL_LITTLE ((unsigned int) 0x10) 370 371 #define RELOC_STD_BITS_JMPTABLE_BIG ((unsigned int) 0x04) 372 #define RELOC_STD_BITS_JMPTABLE_LITTLE ((unsigned int) 0x20) 373 374 #define RELOC_STD_BITS_RELATIVE_BIG ((unsigned int) 0x02) 375 #define RELOC_STD_BITS_RELATIVE_LITTLE ((unsigned int) 0x40) 376 377 #define RELOC_STD_SIZE (BYTES_IN_WORD + 3 + 1) /* Bytes per relocation entry. */ 378 379 struct reloc_std_internal 380 { 381 bfd_vma r_address; /* Address (within segment) to be relocated. */ 382 /* The meaning of r_symbolnum depends on r_extern. */ 383 unsigned int r_symbolnum:24; 384 /* Nonzero means value is a pc-relative offset 385 and it should be relocated for changes in its own address 386 as well as for changes in the symbol or section specified. */ 387 unsigned int r_pcrel:1; 388 /* Length (as exponent of 2) of the field to be relocated. 389 Thus, a value of 2 indicates 1<<2 bytes. */ 390 unsigned int r_length:2; 391 /* 1 => relocate with value of symbol. 392 r_symbolnum is the index of the symbol 393 in files the symbol table. 394 0 => relocate with the address of a segment. 395 r_symbolnum is N_TEXT, N_DATA, N_BSS or N_ABS 396 (the N_EXT bit may be set also, but signifies nothing). */ 397 unsigned int r_extern:1; 398 /* The next three bits are for SunOS shared libraries, and seem to 399 be undocumented. */ 400 unsigned int r_baserel:1; /* Linkage table relative. */ 401 unsigned int r_jmptable:1; /* pc-relative to jump table. */ 402 unsigned int r_relative:1; /* "relative relocation". */ 403 /* unused */ 404 unsigned int r_pad:1; /* Padding -- set to zero. */ 405 }; 406 407 408 /* EXTENDED RELOCS. */ 409 410 struct reloc_ext_external 411 { 412 bfd_byte r_address[BYTES_IN_WORD]; /* Offset of data to relocate. */ 413 bfd_byte r_index[3]; /* Symbol table index of symbol. */ 414 bfd_byte r_type[1]; /* Relocation type. */ 415 bfd_byte r_addend[BYTES_IN_WORD]; /* Datum addend. */ 416 }; 417 418 #ifndef RELOC_EXT_BITS_EXTERN_BIG 419 #define RELOC_EXT_BITS_EXTERN_BIG ((unsigned int) 0x80) 420 #endif 421 422 #ifndef RELOC_EXT_BITS_EXTERN_LITTLE 423 #define RELOC_EXT_BITS_EXTERN_LITTLE ((unsigned int) 0x01) 424 #endif 425 426 #ifndef RELOC_EXT_BITS_TYPE_BIG 427 #define RELOC_EXT_BITS_TYPE_BIG ((unsigned int) 0x1F) 428 #endif 429 430 #ifndef RELOC_EXT_BITS_TYPE_SH_BIG 431 #define RELOC_EXT_BITS_TYPE_SH_BIG 0 432 #endif 433 434 #ifndef RELOC_EXT_BITS_TYPE_LITTLE 435 #define RELOC_EXT_BITS_TYPE_LITTLE ((unsigned int) 0xF8) 436 #endif 437 438 #ifndef RELOC_EXT_BITS_TYPE_SH_LITTLE 439 #define RELOC_EXT_BITS_TYPE_SH_LITTLE 3 440 #endif 441 442 /* Bytes per relocation entry. */ 443 #define RELOC_EXT_SIZE (BYTES_IN_WORD + 3 + 1 + BYTES_IN_WORD) 444 445 enum reloc_type 446 { 447 /* Simple relocations. */ 448 RELOC_8, /* data[0:7] = addend + sv */ 449 RELOC_16, /* data[0:15] = addend + sv */ 450 RELOC_32, /* data[0:31] = addend + sv */ 451 /* PC-rel displacement. */ 452 RELOC_DISP8, /* data[0:7] = addend - pc + sv */ 453 RELOC_DISP16, /* data[0:15] = addend - pc + sv */ 454 RELOC_DISP32, /* data[0:31] = addend - pc + sv */ 455 /* Special. */ 456 RELOC_WDISP30, /* data[0:29] = (addend + sv - pc)>>2 */ 457 RELOC_WDISP22, /* data[0:21] = (addend + sv - pc)>>2 */ 458 RELOC_HI22, /* data[0:21] = (addend + sv)>>10 */ 459 RELOC_22, /* data[0:21] = (addend + sv) */ 460 RELOC_13, /* data[0:12] = (addend + sv) */ 461 RELOC_LO10, /* data[0:9] = (addend + sv) */ 462 RELOC_SFA_BASE, 463 RELOC_SFA_OFF13, 464 /* P.I.C. (base-relative). */ 465 RELOC_BASE10, /* Not sure - maybe we can do this the */ 466 RELOC_BASE13, /* right way now */ 467 RELOC_BASE22, 468 /* For some sort of pc-rel P.I.C. (?) */ 469 RELOC_PC10, 470 RELOC_PC22, 471 /* P.I.C. jump table. */ 472 RELOC_JMP_TBL, 473 /* Reputedly for shared libraries somehow. */ 474 RELOC_SEGOFF16, 475 RELOC_GLOB_DAT, 476 RELOC_JMP_SLOT, 477 RELOC_RELATIVE, 478 479 RELOC_11, 480 RELOC_WDISP2_14, 481 RELOC_WDISP19, 482 483 NO_RELOC 484 }; 485 486 487 struct reloc_internal 488 { 489 bfd_vma r_address; /* Offset of data to relocate. */ 490 long r_index; /* Symbol table index of symbol. */ 491 enum reloc_type r_type; /* Relocation type. */ 492 bfd_vma r_addend; /* Datum addend. */ 493 }; 494 495 /* Q. 496 Should the length of the string table be 4 bytes or 8 bytes ? 497 498 Q. 499 What about archive indexes ? */ 500 501 #endif /* __A_OUT_64_H__ */ 502