1 /* `a.out' object-file definitions, including extensions to 64-bit fields 2 3 Copyright (C) 1999-2020 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 ZMAGIC 0413 /* Code indicating demand-paged executable. */ 60 #define BMAGIC 0415 /* Used by a b.out object. */ 61 62 /* This indicates a demand-paged executable with the header in the text. 63 It is used by 386BSD (and variants) and Linux, at least. */ 64 #ifndef QMAGIC 65 #define QMAGIC 0314 66 #endif 67 # ifndef N_BADMAG 68 # define N_BADMAG(x) (N_MAGIC(x) != OMAGIC \ 69 && N_MAGIC(x) != NMAGIC \ 70 && N_MAGIC(x) != ZMAGIC \ 71 && N_MAGIC(x) != QMAGIC) 72 # endif /* N_BADMAG */ 73 #endif 74 75 #endif 76 77 #ifdef QMAGIC 78 #define N_IS_QMAGIC(x) (N_MAGIC (x) == QMAGIC) 79 #else 80 #define N_IS_QMAGIC(x) (0) 81 #endif 82 83 /* The difference between TARGET_PAGE_SIZE and N_SEGSIZE is that TARGET_PAGE_SIZE is 84 the finest granularity at which you can page something, thus it 85 controls the padding (if any) before the text segment of a ZMAGIC 86 file. N_SEGSIZE is the resolution at which things can be marked as 87 read-only versus read/write, so it controls the padding between the 88 text segment and the data segment (in memory; on disk the padding 89 between them is TARGET_PAGE_SIZE). TARGET_PAGE_SIZE and N_SEGSIZE are the same 90 for most machines, but different for sun3. */ 91 92 /* By default, segment size is constant. But some machines override this 93 to be a function of the a.out header (e.g. machine type). */ 94 95 #ifndef N_SEGSIZE 96 #define N_SEGSIZE(x) SEGMENT_SIZE 97 #endif 98 99 /* Virtual memory address of the text section. 100 This is getting very complicated. A good reason to discard a.out format 101 for something that specifies these fields explicitly. But til then... 102 103 * OMAGIC and NMAGIC files: 104 (object files: text for "relocatable addr 0" right after the header) 105 start at 0, offset is EXEC_BYTES_SIZE, size as stated. 106 * The text address, offset, and size of ZMAGIC files depend 107 on the entry point of the file: 108 * entry point below TEXT_START_ADDR: 109 (hack for SunOS shared libraries) 110 start at 0, offset is 0, size as stated. 111 * If N_HEADER_IN_TEXT(x) is true (which defaults to being the 112 case when the entry point is EXEC_BYTES_SIZE or further into a page): 113 no padding is needed; text can start after exec header. Sun 114 considers the text segment of such files to include the exec header; 115 for BFD's purposes, we don't, which makes more work for us. 116 start at TEXT_START_ADDR + EXEC_BYTES_SIZE, offset is EXEC_BYTES_SIZE, 117 size as stated minus EXEC_BYTES_SIZE. 118 * If N_HEADER_IN_TEXT(x) is false (which defaults to being the case when 119 the entry point is less than EXEC_BYTES_SIZE into a page (e.g. page 120 aligned)): (padding is needed so that text can start at a page boundary) 121 start at TEXT_START_ADDR, offset TARGET_PAGE_SIZE, size as stated. 122 123 Specific configurations may want to hardwire N_HEADER_IN_TEXT, 124 for efficiency or to allow people to play games with the entry point. 125 In that case, you would #define N_HEADER_IN_TEXT(x) as 1 for sunos, 126 and as 0 for most other hosts (Sony News, Vax Ultrix, etc). 127 (Do this in the appropriate bfd target file.) 128 (The default is a heuristic that will break if people try changing 129 the entry point, perhaps with the ld -e flag.) 130 131 * QMAGIC is always like a ZMAGIC for which N_HEADER_IN_TEXT is true, 132 and for which the starting address is TARGET_PAGE_SIZE (or should this be 133 SEGMENT_SIZE?) (TEXT_START_ADDR only applies to ZMAGIC, not to QMAGIC). */ 134 135 /* This macro is only relevant for ZMAGIC files; QMAGIC always has the header 136 in the text. */ 137 #ifndef N_HEADER_IN_TEXT 138 #define N_HEADER_IN_TEXT(x) \ 139 (((x)->a_entry & (TARGET_PAGE_SIZE-1)) >= EXEC_BYTES_SIZE) 140 #endif 141 142 /* Sun shared libraries, not linux. This macro is only relevant for ZMAGIC 143 files. */ 144 #ifndef N_SHARED_LIB 145 #define N_SHARED_LIB(x) (0) 146 #endif 147 148 /* Returning 0 not TEXT_START_ADDR for OMAGIC and NMAGIC is based on 149 the assumption that we are dealing with a .o file, not an 150 executable. This is necessary for OMAGIC (but means we don't work 151 right on the output from ld -N); more questionable for NMAGIC. */ 152 153 #ifndef N_TXTADDR 154 #define N_TXTADDR(x) \ 155 (/* The address of a QMAGIC file is always one page in, \ 156 with the header in the text. */ \ 157 N_IS_QMAGIC (x) \ 158 ? (bfd_vma) TARGET_PAGE_SIZE + EXEC_BYTES_SIZE \ 159 : (N_MAGIC (x) != ZMAGIC \ 160 ? (bfd_vma) 0 /* Object file or NMAGIC. */ \ 161 : (N_SHARED_LIB (x) \ 162 ? (bfd_vma) 0 \ 163 : (N_HEADER_IN_TEXT (x) \ 164 ? (bfd_vma) TEXT_START_ADDR + EXEC_BYTES_SIZE \ 165 : (bfd_vma) TEXT_START_ADDR)))) 166 #endif 167 168 /* If N_HEADER_IN_TEXT is not true for ZMAGIC, there is some padding 169 to make the text segment start at a certain boundary. For most 170 systems, this boundary is TARGET_PAGE_SIZE. But for Linux, in the 171 time-honored tradition of crazy ZMAGIC hacks, it is 1024 which is 172 not what TARGET_PAGE_SIZE needs to be for QMAGIC. */ 173 174 #ifndef ZMAGIC_DISK_BLOCK_SIZE 175 #define ZMAGIC_DISK_BLOCK_SIZE TARGET_PAGE_SIZE 176 #endif 177 178 #define N_DISK_BLOCK_SIZE(x) \ 179 (N_MAGIC(x) == ZMAGIC ? ZMAGIC_DISK_BLOCK_SIZE : TARGET_PAGE_SIZE) 180 181 /* Offset in an a.out of the start of the text section. */ 182 #ifndef N_TXTOFF 183 #define N_TXTOFF(x) \ 184 (/* For {O,N,Q}MAGIC, no padding. */ \ 185 N_MAGIC (x) != ZMAGIC \ 186 ? EXEC_BYTES_SIZE \ 187 : (N_SHARED_LIB (x) \ 188 ? 0 \ 189 : (N_HEADER_IN_TEXT (x) \ 190 ? EXEC_BYTES_SIZE /* No padding. */ \ 191 : ZMAGIC_DISK_BLOCK_SIZE /* A page of padding. */))) 192 #endif 193 /* Size of the text section. It's always as stated, except that we 194 offset it to `undo' the adjustment to N_TXTADDR and N_TXTOFF 195 for ZMAGIC files that nominally include the exec header 196 as part of the first page of text. (BFD doesn't consider the 197 exec header to be part of the text segment.) */ 198 #ifndef N_TXTSIZE 199 #define N_TXTSIZE(x) \ 200 (/* For QMAGIC, we don't consider the header part of the text section. */\ 201 N_IS_QMAGIC (x) \ 202 ? (x)->a_text - EXEC_BYTES_SIZE \ 203 : ((N_MAGIC (x) != ZMAGIC || N_SHARED_LIB (x)) \ 204 ? (x)->a_text \ 205 : (N_HEADER_IN_TEXT (x) \ 206 ? (x)->a_text - EXEC_BYTES_SIZE /* No padding. */ \ 207 : (x)->a_text /* A page of padding. */ ))) 208 #endif 209 /* The address of the data segment in virtual memory. 210 It is the text segment address, plus text segment size, rounded 211 up to a N_SEGSIZE boundary for pure or pageable files. */ 212 #ifndef N_DATADDR 213 #define N_DATADDR(x) \ 214 (N_MAGIC (x) == OMAGIC \ 215 ? (N_TXTADDR (x) + N_TXTSIZE (x)) \ 216 : (N_SEGSIZE (x) + ((N_TXTADDR (x) + N_TXTSIZE (x) - 1) \ 217 & ~ (bfd_vma) (N_SEGSIZE (x) - 1)))) 218 #endif 219 /* The address of the BSS segment -- immediately after the data segment. */ 220 221 #define N_BSSADDR(x) (N_DATADDR (x) + (x)->a_data) 222 223 /* Offsets of the various portions of the file after the text segment. */ 224 225 /* For {Q,Z}MAGIC, there is padding to make the data segment start on 226 a page boundary. Most of the time the a_text field (and thus 227 N_TXTSIZE) already contains this padding. It is possible that for 228 BSDI and/or 386BSD it sometimes doesn't contain the padding, and 229 perhaps we should be adding it here. But this seems kind of 230 questionable and probably should be BSDI/386BSD-specific if we do 231 do it. 232 233 For NMAGIC (at least for hp300 BSD, probably others), there is 234 padding in memory only, not on disk, so we must *not* ever pad here 235 for NMAGIC. */ 236 237 #ifndef N_DATOFF 238 #define N_DATOFF(x) (N_TXTOFF (x) + N_TXTSIZE (x)) 239 #endif 240 #ifndef N_TRELOFF 241 #define N_TRELOFF(x) (N_DATOFF (x) + (x)->a_data) 242 #endif 243 #ifndef N_DRELOFF 244 #define N_DRELOFF(x) (N_TRELOFF (x) + (x)->a_trsize) 245 #endif 246 #ifndef N_SYMOFF 247 #define N_SYMOFF(x) (N_DRELOFF (x) + (x)->a_drsize) 248 #endif 249 #ifndef N_STROFF 250 #define N_STROFF(x) (N_SYMOFF (x) + (x)->a_syms) 251 #endif 252 253 /* Symbols */ 254 #ifndef external_nlist 255 struct external_nlist 256 { 257 bfd_byte e_strx[BYTES_IN_WORD]; /* Index into string table of name. */ 258 bfd_byte e_type[1]; /* Type of symbol. */ 259 bfd_byte e_other[1]; /* Misc info (usually empty). */ 260 bfd_byte e_desc[2]; /* Description field. */ 261 bfd_byte e_value[BYTES_IN_WORD]; /* Value of symbol. */ 262 }; 263 #define EXTERNAL_NLIST_SIZE (BYTES_IN_WORD+4+BYTES_IN_WORD) 264 #endif 265 266 struct internal_nlist 267 { 268 unsigned long n_strx; /* Index into string table of name. */ 269 unsigned char n_type; /* Type of symbol. */ 270 unsigned char n_other; /* Misc info (usually empty). */ 271 unsigned short n_desc; /* Description field. */ 272 bfd_vma n_value; /* Value of symbol. */ 273 }; 274 275 /* The n_type field is the symbol type, containing: */ 276 277 #define N_UNDF 0 /* Undefined symbol. */ 278 #define N_ABS 2 /* Absolute symbol -- defined at particular addr. */ 279 #define N_TEXT 4 /* Text sym -- defined at offset in text seg. */ 280 #define N_DATA 6 /* Data sym -- defined at offset in data seg. */ 281 #define N_BSS 8 /* BSS sym -- defined at offset in zero'd seg. */ 282 #define N_COMM 0x12 /* Common symbol (visible after shared lib dynlink). */ 283 #define N_FN 0x1f /* File name of .o file. */ 284 #define N_FN_SEQ 0x0C /* N_FN from Sequent compilers (sigh). */ 285 /* Note: N_EXT can only be usefully OR-ed with N_UNDF, N_ABS, N_TEXT, 286 N_DATA, or N_BSS. When the low-order bit of other types is set, 287 (e.g. N_WARNING versus N_FN), they are two different types. */ 288 #define N_EXT 1 /* External symbol (as opposed to local-to-this-file). */ 289 #define N_TYPE 0x1e 290 #define N_STAB 0xe0 /* If any of these bits are on, it's a debug symbol. */ 291 292 #define N_INDR 0x0a 293 294 /* The following symbols refer to set elements. 295 All the N_SET[ATDB] symbols with the same name form one set. 296 Space is allocated for the set in the text section, and each set 297 elements value is stored into one word of the space. 298 The first word of the space is the length of the set (number of elements). 299 300 The address of the set is made into an N_SETV symbol 301 whose name is the same as the name of the set. 302 This symbol acts like a N_DATA global symbol 303 in that it can satisfy undefined external references. */ 304 305 /* These appear as input to LD, in a .o file. */ 306 #define N_SETA 0x14 /* Absolute set element symbol. */ 307 #define N_SETT 0x16 /* Text set element symbol. */ 308 #define N_SETD 0x18 /* Data set element symbol. */ 309 #define N_SETB 0x1A /* Bss set element symbol. */ 310 311 /* This is output from LD. */ 312 #define N_SETV 0x1C /* Pointer to set vector in data area. */ 313 314 /* Warning symbol. The text gives a warning message, the next symbol 315 in the table will be undefined. When the symbol is referenced, the 316 message is printed. */ 317 318 #define N_WARNING 0x1e 319 320 /* Weak symbols. These are a GNU extension to the a.out format. The 321 semantics are those of ELF weak symbols. Weak symbols are always 322 externally visible. The N_WEAK? values are squeezed into the 323 available slots. The value of a N_WEAKU symbol is 0. The values 324 of the other types are the definitions. */ 325 #define N_WEAKU 0x0d /* Weak undefined symbol. */ 326 #define N_WEAKA 0x0e /* Weak absolute symbol. */ 327 #define N_WEAKT 0x0f /* Weak text symbol. */ 328 #define N_WEAKD 0x10 /* Weak data symbol. */ 329 #define N_WEAKB 0x11 /* Weak bss symbol. */ 330 331 /* Relocations 332 333 There are two types of relocation flavours for a.out systems, 334 standard and extended. The standard form is used on systems where the 335 instruction has room for all the bits of an offset to the operand, whilst 336 the extended form is used when an address operand has to be split over n 337 instructions. Eg, on the 68k, each move instruction can reference 338 the target with a displacement of 16 or 32 bits. On the sparc, move 339 instructions use an offset of 14 bits, so the offset is stored in 340 the reloc field, and the data in the section is ignored. */ 341 342 /* This structure describes a single relocation to be performed. 343 The text-relocation section of the file is a vector of these structures, 344 all of which apply to the text section. 345 Likewise, the data-relocation section applies to the data section. */ 346 347 struct reloc_std_external 348 { 349 bfd_byte r_address[BYTES_IN_WORD]; /* Offset of data to relocate. */ 350 bfd_byte r_index[3]; /* Symbol table index of symbol. */ 351 bfd_byte r_type[1]; /* Relocation type. */ 352 }; 353 354 #define RELOC_STD_BITS_PCREL_BIG ((unsigned int) 0x80) 355 #define RELOC_STD_BITS_PCREL_LITTLE ((unsigned int) 0x01) 356 357 #define RELOC_STD_BITS_LENGTH_BIG ((unsigned int) 0x60) 358 #define RELOC_STD_BITS_LENGTH_SH_BIG 5 359 #define RELOC_STD_BITS_LENGTH_LITTLE ((unsigned int) 0x06) 360 #define RELOC_STD_BITS_LENGTH_SH_LITTLE 1 361 362 #define RELOC_STD_BITS_EXTERN_BIG ((unsigned int) 0x10) 363 #define RELOC_STD_BITS_EXTERN_LITTLE ((unsigned int) 0x08) 364 365 #define RELOC_STD_BITS_BASEREL_BIG ((unsigned int) 0x08) 366 #define RELOC_STD_BITS_BASEREL_LITTLE ((unsigned int) 0x10) 367 368 #define RELOC_STD_BITS_JMPTABLE_BIG ((unsigned int) 0x04) 369 #define RELOC_STD_BITS_JMPTABLE_LITTLE ((unsigned int) 0x20) 370 371 #define RELOC_STD_BITS_RELATIVE_BIG ((unsigned int) 0x02) 372 #define RELOC_STD_BITS_RELATIVE_LITTLE ((unsigned int) 0x40) 373 374 #define RELOC_STD_SIZE (BYTES_IN_WORD + 3 + 1) /* Bytes per relocation entry. */ 375 376 struct reloc_std_internal 377 { 378 bfd_vma r_address; /* Address (within segment) to be relocated. */ 379 /* The meaning of r_symbolnum depends on r_extern. */ 380 unsigned int r_symbolnum:24; 381 /* Nonzero means value is a pc-relative offset 382 and it should be relocated for changes in its own address 383 as well as for changes in the symbol or section specified. */ 384 unsigned int r_pcrel:1; 385 /* Length (as exponent of 2) of the field to be relocated. 386 Thus, a value of 2 indicates 1<<2 bytes. */ 387 unsigned int r_length:2; 388 /* 1 => relocate with value of symbol. 389 r_symbolnum is the index of the symbol 390 in files the symbol table. 391 0 => relocate with the address of a segment. 392 r_symbolnum is N_TEXT, N_DATA, N_BSS or N_ABS 393 (the N_EXT bit may be set also, but signifies nothing). */ 394 unsigned int r_extern:1; 395 /* The next three bits are for SunOS shared libraries, and seem to 396 be undocumented. */ 397 unsigned int r_baserel:1; /* Linkage table relative. */ 398 unsigned int r_jmptable:1; /* pc-relative to jump table. */ 399 unsigned int r_relative:1; /* "relative relocation". */ 400 /* unused */ 401 unsigned int r_pad:1; /* Padding -- set to zero. */ 402 }; 403 404 405 /* EXTENDED RELOCS. */ 406 407 struct reloc_ext_external 408 { 409 bfd_byte r_address[BYTES_IN_WORD]; /* Offset of data to relocate. */ 410 bfd_byte r_index[3]; /* Symbol table index of symbol. */ 411 bfd_byte r_type[1]; /* Relocation type. */ 412 bfd_byte r_addend[BYTES_IN_WORD]; /* Datum addend. */ 413 }; 414 415 #ifndef RELOC_EXT_BITS_EXTERN_BIG 416 #define RELOC_EXT_BITS_EXTERN_BIG ((unsigned int) 0x80) 417 #endif 418 419 #ifndef RELOC_EXT_BITS_EXTERN_LITTLE 420 #define RELOC_EXT_BITS_EXTERN_LITTLE ((unsigned int) 0x01) 421 #endif 422 423 #ifndef RELOC_EXT_BITS_TYPE_BIG 424 #define RELOC_EXT_BITS_TYPE_BIG ((unsigned int) 0x1F) 425 #endif 426 427 #ifndef RELOC_EXT_BITS_TYPE_SH_BIG 428 #define RELOC_EXT_BITS_TYPE_SH_BIG 0 429 #endif 430 431 #ifndef RELOC_EXT_BITS_TYPE_LITTLE 432 #define RELOC_EXT_BITS_TYPE_LITTLE ((unsigned int) 0xF8) 433 #endif 434 435 #ifndef RELOC_EXT_BITS_TYPE_SH_LITTLE 436 #define RELOC_EXT_BITS_TYPE_SH_LITTLE 3 437 #endif 438 439 /* Bytes per relocation entry. */ 440 #define RELOC_EXT_SIZE (BYTES_IN_WORD + 3 + 1 + BYTES_IN_WORD) 441 442 enum reloc_type 443 { 444 /* Simple relocations. */ 445 RELOC_8, /* data[0:7] = addend + sv */ 446 RELOC_16, /* data[0:15] = addend + sv */ 447 RELOC_32, /* data[0:31] = addend + sv */ 448 /* PC-rel displacement. */ 449 RELOC_DISP8, /* data[0:7] = addend - pc + sv */ 450 RELOC_DISP16, /* data[0:15] = addend - pc + sv */ 451 RELOC_DISP32, /* data[0:31] = addend - pc + sv */ 452 /* Special. */ 453 RELOC_WDISP30, /* data[0:29] = (addend + sv - pc)>>2 */ 454 RELOC_WDISP22, /* data[0:21] = (addend + sv - pc)>>2 */ 455 RELOC_HI22, /* data[0:21] = (addend + sv)>>10 */ 456 RELOC_22, /* data[0:21] = (addend + sv) */ 457 RELOC_13, /* data[0:12] = (addend + sv) */ 458 RELOC_LO10, /* data[0:9] = (addend + sv) */ 459 RELOC_SFA_BASE, 460 RELOC_SFA_OFF13, 461 /* P.I.C. (base-relative). */ 462 RELOC_BASE10, /* Not sure - maybe we can do this the */ 463 RELOC_BASE13, /* right way now */ 464 RELOC_BASE22, 465 /* For some sort of pc-rel P.I.C. (?) */ 466 RELOC_PC10, 467 RELOC_PC22, 468 /* P.I.C. jump table. */ 469 RELOC_JMP_TBL, 470 /* Reputedly for shared libraries somehow. */ 471 RELOC_SEGOFF16, 472 RELOC_GLOB_DAT, 473 RELOC_JMP_SLOT, 474 RELOC_RELATIVE, 475 476 RELOC_11, 477 RELOC_WDISP2_14, 478 RELOC_WDISP19, 479 480 NO_RELOC 481 }; 482 483 484 struct reloc_internal 485 { 486 bfd_vma r_address; /* Offset of data to relocate. */ 487 long r_index; /* Symbol table index of symbol. */ 488 enum reloc_type r_type; /* Relocation type. */ 489 bfd_vma r_addend; /* Datum addend. */ 490 }; 491 492 /* Q. 493 Should the length of the string table be 4 bytes or 8 bytes ? 494 495 Q. 496 What about archive indexes ? */ 497 498 #endif /* __A_OUT_64_H__ */ 499