/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_ELFNOTE_H #define _LINUX_ELFNOTE_H /* * Helper macros to generate ELF Note structures, which are put into a * PT_NOTE segment of the final vmlinux image. These are useful for * including name-value pairs of metadata into the kernel binary (or * modules?) for use by external programs. * * Each note has three parts: a name, a type and a desc. The name is * intended to distinguish the note's originator, so it would be a * company, project, subsystem, etc; it must be in a suitable form for * use in a section name. The type is an integer which is used to tag * the data, and is considered to be within the "name" namespace (so * "FooCo"'s type 42 is distinct from "BarProj"'s type 42). The * "desc" field is the actual data. There are no constraints on the * desc field's contents, though typically they're fairly small. * * All notes from a given NAME are put into a section named * .note.NAME. When the kernel image is finally linked, all the notes * are packed into a single .notes section, which is mapped into the * PT_NOTE segment. Because notes for a given name are grouped into * the same section, they'll all be adjacent the output file. * * This file defines macros for both C and assembler use. Their * syntax is slightly different, but they're semantically similar. * * See the ELF specification for more detail about ELF notes. */ #ifdef __ASSEMBLER__ /* * Generate a structure with the same shape as Elf{32,64}_Nhdr (which * turn out to be the same size and shape), followed by the name and * desc data with appropriate padding. The 'desctype' argument is the * assembler pseudo op defining the type of the data e.g. .asciz while * 'descdata' is the data itself e.g. "hello, world". * * e.g. ELFNOTE(XYZCo, 42, .asciz, "forty-two") * ELFNOTE(XYZCo, 12, .long, 0xdeadbeef) */ #define ELFNOTE_START(name, type, flags) … #define ELFNOTE_END … #define ELFNOTE(name, type, desc) … #else /* !__ASSEMBLER__ */ #include <uapi/linux/elf.h> /* * Use an anonymous structure which matches the shape of * Elf{32,64}_Nhdr, but includes the name and desc data. The size and * type of name and desc depend on the macro arguments. "name" must * be a literal string, and "desc" must be passed by value. You may * only define one note per line, since __LINE__ is used to generate * unique symbols. */ #define _ELFNOTE_PASTE … #define _ELFNOTE … #define ELFNOTE … #define ELFNOTE32 … #define ELFNOTE64 … #endif /* __ASSEMBLER__ */ #endif /* _LINUX_ELFNOTE_H */
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