1 /* SPDX-License-Identifier: GPL-2.0 */ 1
2 #ifndef _LINUX_ELFNOTE_H
3 #define _LINUX_ELFNOTE_H
4 /*
5 * Helper macros to generate ELF Note structur
6 * PT_NOTE segment of the final vmlinux image.
7 * including name-value pairs of metadata into
8 * modules?) for use by external programs.
9 *
10 * Each note has three parts: a name, a type a
11 * intended to distinguish the note's originat
12 * company, project, subsystem, etc; it must b
13 * use in a section name. The type is an inte
14 * the data, and is considered to be within th
15 * "FooCo"'s type 42 is distinct from "BarProj
16 * "desc" field is the actual data. There are
17 * desc field's contents, though typically the
18 *
19 * All notes from a given NAME are put into a
20 * .note.NAME. When the kernel image is final
21 * are packed into a single .notes section, wh
22 * PT_NOTE segment. Because notes for a given
23 * the same section, they'll all be adjacent t
24 *
25 * This file defines macros for both C and ass
26 * syntax is slightly different, but they're s
27 *
28 * See the ELF specification for more detail a
29 */
30
31 #ifdef __ASSEMBLER__
32 /*
33 * Generate a structure with the same shape as
34 * turn out to be the same size and shape), fo
35 * desc data with appropriate padding. The 'd
36 * assembler pseudo op defining the type of th
37 * 'descdata' is the data itself e.g. "hello,
38 *
39 * e.g. ELFNOTE(XYZCo, 42, .asciz, "forty-two"
40 * ELFNOTE(XYZCo, 12, .long, 0xdeadbeef)
41 */
42 #define ELFNOTE_START(name, type, flags)
43 .pushsection .note.name, flags,@note ;
44 .balign 4 ;
45 .long 2f - 1f /* namesz */ ;
46 .long 4484f - 3f /* descsz */ ;
47 .long type ;
48 1:.asciz #name ;
49 2:.balign 4 ;
50 3:
51
52 #define ELFNOTE_END
53 4484:.balign 4 ;
54 .popsection ;
55
56 #define ELFNOTE(name, type, desc)
57 ELFNOTE_START(name, type, "a")
58 desc ;
59 ELFNOTE_END
60
61 #else /* !__ASSEMBLER__ */
62 #include <uapi/linux/elf.h>
63 /*
64 * Use an anonymous structure which matches th
65 * Elf{32,64}_Nhdr, but includes the name and
66 * type of name and desc depend on the macro a
67 * be a literal string, and "desc" must be pas
68 * only define one note per line, since __LINE
69 * unique symbols.
70 */
71 #define _ELFNOTE_PASTE(a,b) a##b
72 #define _ELFNOTE(size, name, unique, type, des
73 static const struct {
74 struct elf##size##_note _nhdr;
75 unsigned char _name[sizeof(nam
76 __attribute__((aligned(sizeof(
77 typeof(desc) _desc
78 __attribute__((al
79 } _ELFNOTE_PASTE(_note_, unique)
80 __used
81 __attribute__((section(".note.
82 aligned(sizeof(
83 unused)) = {
84 {
85 sizeof(name),
86 sizeof(desc),
87 type,
88 },
89 name,
90 desc
91 }
92 #define ELFNOTE(size, name, type, desc)
93 _ELFNOTE(size, name, __LINE__, type, d
94
95 #define ELFNOTE32(name, type, desc) ELFNOTE(32
96 #define ELFNOTE64(name, type, desc) ELFNOTE(64
97 #endif /* __ASSEMBLER__ */
98
99 #endif /* _LINUX_ELFNOTE_H */
100
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