xref: /linux-6.15/include/linux/flat.h (revision 06d2bfed)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Copyright (C) 2002-2003  David McCullough <[email protected]>
4  * Copyright (C) 1998       Kenneth Albanowski <[email protected]>
5  *                          The Silver Hammer Group, Ltd.
6  *
7  * This file provides the definitions and structures needed to
8  * support uClinux flat-format executables.
9  */
10 #ifndef _LINUX_FLAT_H
11 #define _LINUX_FLAT_H
12 
13 #define	FLAT_VERSION			0x00000004L
14 
15 #ifdef CONFIG_BINFMT_SHARED_FLAT
16 #define	MAX_SHARED_LIBS			(4)
17 #else
18 #define	MAX_SHARED_LIBS			(1)
19 #endif
20 
21 /*
22  * To make everything easier to port and manage cross platform
23  * development,  all fields are in network byte order.
24  */
25 
26 struct flat_hdr {
27 	char magic[4];
28 	unsigned long rev;          /* version (as above) */
29 	unsigned long entry;        /* Offset of first executable instruction
30 	                               with text segment from beginning of file */
31 	unsigned long data_start;   /* Offset of data segment from beginning of
32 	                               file */
33 	unsigned long data_end;     /* Offset of end of data segment
34 	                               from beginning of file */
35 	unsigned long bss_end;      /* Offset of end of bss segment from beginning
36 	                               of file */
37 
38 	/* (It is assumed that data_end through bss_end forms the bss segment.) */
39 
40 	unsigned long stack_size;   /* Size of stack, in bytes */
41 	unsigned long reloc_start;  /* Offset of relocation records from
42 	                               beginning of file */
43 	unsigned long reloc_count;  /* Number of relocation records */
44 	unsigned long flags;
45 	unsigned long build_date;   /* When the program/library was built */
46 	unsigned long filler[5];    /* Reservered, set to zero */
47 };
48 
49 #define FLAT_FLAG_RAM    0x0001 /* load program entirely into RAM */
50 #define FLAT_FLAG_GOTPIC 0x0002 /* program is PIC with GOT */
51 #define FLAT_FLAG_GZIP   0x0004 /* all but the header is compressed */
52 #define FLAT_FLAG_GZDATA 0x0008 /* only data/relocs are compressed (for XIP) */
53 #define FLAT_FLAG_KTRACE 0x0010 /* output useful kernel trace for debugging */
54 
55 /*
56  * While it would be nice to keep this header clean,  users of older
57  * tools still need this support in the kernel.  So this section is
58  * purely for compatibility with old tool chains.
59  *
60  * DO NOT make changes or enhancements to the old format please,  just work
61  *        with the format above,  except to fix bugs with old format support.
62  */
63 
64 #define	OLD_FLAT_VERSION			0x00000002L
65 #define OLD_FLAT_RELOC_TYPE_TEXT	0
66 #define OLD_FLAT_RELOC_TYPE_DATA	1
67 #define OLD_FLAT_RELOC_TYPE_BSS		2
68 
69 typedef union {
70 	unsigned long	value;
71 	struct {
72 # if defined(mc68000) && !defined(CONFIG_COLDFIRE)
73 		signed long offset : 30;
74 		unsigned long type : 2;
75 #   	define OLD_FLAT_FLAG_RAM    0x1 /* load program entirely into RAM */
76 # elif defined(__BIG_ENDIAN_BITFIELD)
77 		unsigned long type : 2;
78 		signed long offset : 30;
79 #   	define OLD_FLAT_FLAG_RAM    0x1 /* load program entirely into RAM */
80 # elif defined(__LITTLE_ENDIAN_BITFIELD)
81 		signed long offset : 30;
82 		unsigned long type : 2;
83 #   	define OLD_FLAT_FLAG_RAM    0x1 /* load program entirely into RAM */
84 # else
85 #   	error "Unknown bitfield order for flat files."
86 # endif
87 	} reloc;
88 } flat_v2_reloc_t;
89 
90 #endif /* _LINUX_FLAT_H */
91