include/uapi/linux/coff.h

   1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2 /* This file is derived from the GAS 2.1.4 assembler control file.
   3    The GAS product is under the GNU General Public License, version 2 or later.
   4    As such, this file is also under that license.
   5
   6    If the file format changes in the COFF object, this file should be
   7    subsequently updated to reflect the changes.
   8
   9    The actual loader module only uses a few of these structures. The full
  10    set is documented here because I received the full set. If you wish
  11    more information about COFF, then O'Reilly has a very excellent book.
  12 */
  13
  14 #ifndef _UAPI_LINUX_COFF_H
  15 #define _UAPI_LINUX_COFF_H
  16
  17 #define  E_SYMNMLEN  8   /* Number of characters in a symbol name         */
  18 #define  E_FILNMLEN 14   /* Number of characters in a file name           */
  19 #define  E_DIMNUM    4   /* Number of array dimensions in auxiliary entry */
  20
  21 /*
  22  * These defines are byte order independent. There is no alignment of fields
  23  * permitted in the structures. Therefore they are declared as characters
  24  * and the values loaded from the character positions. It also makes it
  25  * nice to have it "endian" independent.
  26  */
  27
  28 /* Load a short int from the following tables with little-endian formats */
  29 #define COFF_SHORT_L(ps) ((short)(((unsigned short)((unsigned char)ps[1])<<8)|\
  30                                   ((unsigned short)((unsigned char)ps[0]))))
  31
  32 /* Load a long int from the following tables with little-endian formats */
  33 #define COFF_LONG_L(ps) (((long)(((unsigned long)((unsigned char)ps[3])<<24) |\
  34                                  ((unsigned long)((unsigned char)ps[2])<<16) |\
  35                                  ((unsigned long)((unsigned char)ps[1])<<8)  |\
  36                                  ((unsigned long)((unsigned char)ps[0])))))
  37
  38 /* Load a short int from the following tables with big-endian formats */
  39 #define COFF_SHORT_H(ps) ((short)(((unsigned short)((unsigned char)ps[0])<<8)|\
  40                                   ((unsigned short)((unsigned char)ps[1]))))
  41
  42 /* Load a long int from the following tables with big-endian formats */
  43 #define COFF_LONG_H(ps) (((long)(((unsigned long)((unsigned char)ps[0])<<24) |\
  44                                  ((unsigned long)((unsigned char)ps[1])<<16) |\
  45                                  ((unsigned long)((unsigned char)ps[2])<<8)  |\
  46                                  ((unsigned long)((unsigned char)ps[3])))))
  47
  48 /* These may be overridden later by brain dead implementations which generate
  49    a big-endian header with little-endian data. In that case, generate a
  50    replacement macro which tests a flag and uses either of the two above
  51    as appropriate. */
  52
  53 #define COFF_LONG(v)   COFF_LONG_L(v)
  54 #define COFF_SHORT(v)  COFF_SHORT_L(v)
  55
  56 /*** coff information for Intel 386/486.  */
  57
  58 /********************** FILE HEADER **********************/
  59
  60 struct COFF_filehdr {
  61         char f_magic[2];        /* magic number                 */
  62         char f_nscns[2];        /* number of sections           */
  63         char f_timdat[4];       /* time & date stamp            */
  64         char f_symptr[4];       /* file pointer to symtab       */
  65         char f_nsyms[4];        /* number of symtab entries     */
  66         char f_opthdr[2];       /* sizeof(optional hdr)         */
  67         char f_flags[2];        /* flags                        */
  68 };
  69
  70 /*
  71  *   Bits for f_flags:
  72  *
  73  *      F_RELFLG        relocation info stripped from file
  74  *      F_EXEC          file is executable  (i.e. no unresolved external
  75  *                      references)
  76  *      F_LNNO          line numbers stripped from file
  77  *      F_LSYMS         local symbols stripped from file
  78  *      F_MINMAL        this is a minimal object file (".m") output of fextract
  79  *      F_UPDATE        this is a fully bound update file, output of ogen
  80  *      F_SWABD         this file has had its bytes swabbed (in names)
  81  *      F_AR16WR        this file has the byte ordering of an AR16WR
  82  *                      (e.g. 11/70) machine
  83  *      F_AR32WR        this file has the byte ordering of an AR32WR machine
  84  *                      (e.g. vax and iNTEL 386)
  85  *      F_AR32W         this file has the byte ordering of an AR32W machine
  86  *                      (e.g. 3b,maxi)
  87  *      F_PATCH         file contains "patch" list in optional header
  88  *      F_NODF          (minimal file only) no decision functions for
  89  *                      replaced functions
  90  */
  91
  92 #define  COFF_F_RELFLG          0000001
  93 #define  COFF_F_EXEC            0000002
  94 #define  COFF_F_LNNO            0000004
  95 #define  COFF_F_LSYMS           0000010
  96 #define  COFF_F_MINMAL          0000020
  97 #define  COFF_F_UPDATE          0000040
  98 #define  COFF_F_SWABD           0000100
  99 #define  COFF_F_AR16WR          0000200
 100 #define  COFF_F_AR32WR          0000400
 101 #define  COFF_F_AR32W           0001000
 102 #define  COFF_F_PATCH           0002000
 103 #define  COFF_F_NODF            0002000
 104
 105 #define COFF_I386MAGIC          0x14c   /* Linux's system    */
 106
 107 #if 0   /* Perhaps, someday, these formats may be used.      */
 108 #define COFF_I386PTXMAGIC       0x154
 109 #define COFF_I386AIXMAGIC       0x175   /* IBM's AIX system  */
 110 #define COFF_I386BADMAG(x) ((COFF_SHORT((x).f_magic) != COFF_I386MAGIC) \
 111                           && COFF_SHORT((x).f_magic) != COFF_I386PTXMAGIC \
 112                           && COFF_SHORT((x).f_magic) != COFF_I386AIXMAGIC)
 113 #else
 114 #define COFF_I386BADMAG(x) (COFF_SHORT((x).f_magic) != COFF_I386MAGIC)
 115 #endif
 116
 117 #define COFF_FILHDR     struct COFF_filehdr
 118 #define COFF_FILHSZ     sizeof(COFF_FILHDR)
 119
 120 /********************** AOUT "OPTIONAL HEADER" **********************/
 121
 122 /* Linux COFF must have this "optional" header. Standard COFF has no entry
 123    location for the "entry" point. They normally would start with the first
 124    location of the .text section. This is not a good idea for linux. So,
 125    the use of this "optional" header is not optional. It is required.
 126
 127    Do not be tempted to assume that the size of the optional header is
 128    a constant and simply index the next byte by the size of this structure.
 129    Use the 'f_opthdr' field in the main coff header for the size of the
 130    structure actually written to the file!!
 131 */
 132
 133 typedef struct
 134 {
 135   char  magic[2];               /* type of file                          */
 136   char  vstamp[2];              /* version stamp                         */
 137   char  tsize[4];               /* text size in bytes, padded to FW bdry */
 138   char  dsize[4];               /* initialized   data "   "              */
 139   char  bsize[4];               /* uninitialized data "   "              */
 140   char  entry[4];               /* entry pt.                             */
 141   char  text_start[4];          /* base of text used for this file       */
 142   char  data_start[4];          /* base of data used for this file       */
 143 }
 144 COFF_AOUTHDR;
 145
 146 #define COFF_AOUTSZ (sizeof(COFF_AOUTHDR))
 147
 148 #define COFF_STMAGIC    0401
 149 #define COFF_OMAGIC     0404
 150 #define COFF_JMAGIC     0407    /* dirty text and data image, can't share  */
 151 #define COFF_DMAGIC     0410    /* dirty text segment, data aligned        */
 152 #define COFF_ZMAGIC     0413    /* The proper magic number for executables  */
 153 #define COFF_SHMAGIC    0443    /* shared library header                   */
 154
 155 /********************** SECTION HEADER **********************/
 156
 157 struct COFF_scnhdr {
 158   char          s_name[8];      /* section name                     */
 159   char          s_paddr[4];     /* physical address, aliased s_nlib */
 160   char          s_vaddr[4];     /* virtual address                  */
 161   char          s_size[4];      /* section size                     */
 162   char          s_scnptr[4];    /* file ptr to raw data for section */
 163   char          s_relptr[4];    /* file ptr to relocation           */
 164   char          s_lnnoptr[4];   /* file ptr to line numbers         */
 165   char          s_nreloc[2];    /* number of relocation entries     */
 166   char          s_nlnno[2];     /* number of line number entries    */
 167   char          s_flags[4];     /* flags                            */
 168 };
 169
 170 #define COFF_SCNHDR     struct COFF_scnhdr
 171 #define COFF_SCNHSZ     sizeof(COFF_SCNHDR)
 172
 173 /*
 174  * names of "special" sections
 175  */
 176
 177 #define COFF_TEXT       ".text"
 178 #define COFF_DATA       ".data"
 179 #define COFF_BSS        ".bss"
 180 #define COFF_COMMENT    ".comment"
 181 #define COFF_LIB        ".lib"
 182
 183 #define COFF_SECT_TEXT  0      /* Section for instruction code             */
 184 #define COFF_SECT_DATA  1      /* Section for initialized globals          */
 185 #define COFF_SECT_BSS   2      /* Section for un-initialized globals       */
 186 #define COFF_SECT_REQD  3      /* Minimum number of sections for good file */
 187
 188 #define COFF_STYP_REG     0x00 /* regular segment                          */
 189 #define COFF_STYP_DSECT   0x01 /* dummy segment                            */
 190 #define COFF_STYP_NOLOAD  0x02 /* no-load segment                          */
 191 #define COFF_STYP_GROUP   0x04 /* group segment                            */
 192 #define COFF_STYP_PAD     0x08 /* .pad segment                             */
 193 #define COFF_STYP_COPY    0x10 /* copy section                             */
 194 #define COFF_STYP_TEXT    0x20 /* .text segment                            */
 195 #define COFF_STYP_DATA    0x40 /* .data segment                            */
 196 #define COFF_STYP_BSS     0x80 /* .bss segment                             */
 197 #define COFF_STYP_INFO   0x200 /* .comment section                         */
 198 #define COFF_STYP_OVER   0x400 /* overlay section                          */
 199 #define COFF_STYP_LIB    0x800 /* library section                          */
 200
 201 /*
 202  * Shared libraries have the following section header in the data field for
 203  * each library.
 204  */
 205
 206 struct COFF_slib {
 207   char          sl_entsz[4];    /* Size of this entry               */
 208   char          sl_pathndx[4];  /* size of the header field         */
 209 };
 210
 211 #define COFF_SLIBHD     struct COFF_slib
 212 #define COFF_SLIBSZ     sizeof(COFF_SLIBHD)
 213
 214 /********************** LINE NUMBERS **********************/
 215
 216 /* 1 line number entry for every "breakpointable" source line in a section.
 217  * Line numbers are grouped on a per function basis; first entry in a function
 218  * grouping will have l_lnno = 0 and in place of physical address will be the
 219  * symbol table index of the function name.
 220  */
 221
 222 struct COFF_lineno {
 223   union {
 224     char l_symndx[4];   /* function name symbol index, iff l_lnno == 0*/
 225     char l_paddr[4];    /* (physical) address of line number    */
 226   } l_addr;
 227   char l_lnno[2];       /* line number          */
 228 };
 229
 230 #define COFF_LINENO     struct COFF_lineno
 231 #define COFF_LINESZ     6
 232
 233 /********************** SYMBOLS **********************/
 234
 235 #define COFF_E_SYMNMLEN  8      /* # characters in a short symbol name  */
 236 #define COFF_E_FILNMLEN 14      /* # characters in a file name          */
 237 #define COFF_E_DIMNUM    4      /* # array dimensions in auxiliary entry */
 238
 239 /*
 240  *  All symbols and sections have the following definition
 241  */
 242
 243 struct COFF_syment
 244 {
 245   union {
 246     char e_name[E_SYMNMLEN];    /* Symbol name (first 8 characters) */
 247     struct {
 248       char e_zeroes[4];         /* Leading zeros */
 249       char e_offset[4];         /* Offset if this is a header section */
 250     } e;
 251   } e;
 252
 253   char e_value[4];              /* Value (address) of the segment */
 254   char e_scnum[2];              /* Section number */
 255   char e_type[2];               /* Type of section */
 256   char e_sclass[1];             /* Loader class */
 257   char e_numaux[1];             /* Number of auxiliary entries which follow */
 258 };
 259
 260 #define COFF_N_BTMASK   (0xf)   /* Mask for important class bits */
 261 #define COFF_N_TMASK    (0x30)  /* Mask for important type bits  */
 262 #define COFF_N_BTSHFT   (4)     /* # bits to shift class field   */
 263 #define COFF_N_TSHIFT   (2)     /* # bits to shift type field    */
 264
 265 /*
 266  *  Auxiliary entries because the main table is too limiting.
 267  */
 268
 269 union COFF_auxent {
 270
 271 /*
 272  *  Debugger information
 273  */
 274
 275   struct {
 276     char x_tagndx[4];           /* str, un, or enum tag indx */
 277     union {
 278       struct {
 279         char  x_lnno[2];        /* declaration line number */
 280         char  x_size[2];        /* str/union/array size */
 281       } x_lnsz;
 282       char x_fsize[4];          /* size of function */
 283     } x_misc;
 284
 285     union {
 286       struct {                  /* if ISFCN, tag, or .bb */
 287         char x_lnnoptr[4];      /* ptr to fcn line # */
 288         char x_endndx[4];       /* entry ndx past block end */
 289       } x_fcn;
 290
 291       struct {                  /* if ISARY, up to 4 dimen. */
 292         char x_dimen[E_DIMNUM][2];
 293       } x_ary;
 294     } x_fcnary;
 295
 296     char x_tvndx[2];    /* tv index */
 297   } x_sym;
 298
 299 /*
 300  *   Source file names (debugger information)
 301  */
 302
 303   union {
 304     char x_fname[E_FILNMLEN];
 305     struct {
 306       char x_zeroes[4];
 307       char x_offset[4];
 308     } x_n;
 309   } x_file;
 310
 311 /*
 312  *   Section information
 313  */
 314
 315   struct {
 316     char x_scnlen[4];   /* section length */
 317     char x_nreloc[2];   /* # relocation entries */
 318     char x_nlinno[2];   /* # line numbers */
 319   } x_scn;
 320
 321 /*
 322  *   Transfer vector (branch table)
 323  */
 324
 325   struct {
 326     char x_tvfill[4];   /* tv fill value */
 327     char x_tvlen[2];    /* length of .tv */
 328     char x_tvran[2][2]; /* tv range */
 329   } x_tv;               /* info about .tv section (in auxent of symbol .tv)) */
 330 };
 331
 332 #define COFF_SYMENT     struct COFF_syment
 333 #define COFF_SYMESZ     18
 334 #define COFF_AUXENT     union COFF_auxent
 335 #define COFF_AUXESZ     18
 336
 337 #define COFF_ETEXT      "etext"
 338
 339 /********************** RELOCATION DIRECTIVES **********************/
 340
 341 struct COFF_reloc {
 342   char r_vaddr[4];        /* Virtual address of item    */
 343   char r_symndx[4];       /* Symbol index in the symtab */
 344   char r_type[2];         /* Relocation type            */
 345 };
 346
 347 #define COFF_RELOC struct COFF_reloc
 348 #define COFF_RELSZ 10
 349
 350 #define COFF_DEF_DATA_SECTION_ALIGNMENT  4
 351 #define COFF_DEF_BSS_SECTION_ALIGNMENT   4
 352 #define COFF_DEF_TEXT_SECTION_ALIGNMENT  4
 353
 354 /* For new sections we haven't heard of before */
 355 #define COFF_DEF_SECTION_ALIGNMENT       4
 356
 357 #endif /* _UAPI_LINUX_COFF_H */