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 */
358