cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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elfnote.h (3626B)


      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef _LINUX_ELFNOTE_H
      3#define _LINUX_ELFNOTE_H
      4/*
      5 * Helper macros to generate ELF Note structures, which are put into a
      6 * PT_NOTE segment of the final vmlinux image.  These are useful for
      7 * including name-value pairs of metadata into the kernel binary (or
      8 * modules?) for use by external programs.
      9 *
     10 * Each note has three parts: a name, a type and a desc.  The name is
     11 * intended to distinguish the note's originator, so it would be a
     12 * company, project, subsystem, etc; it must be in a suitable form for
     13 * use in a section name.  The type is an integer which is used to tag
     14 * the data, and is considered to be within the "name" namespace (so
     15 * "FooCo"'s type 42 is distinct from "BarProj"'s type 42).  The
     16 * "desc" field is the actual data.  There are no constraints on the
     17 * desc field's contents, though typically they're fairly small.
     18 *
     19 * All notes from a given NAME are put into a section named
     20 * .note.NAME.  When the kernel image is finally linked, all the notes
     21 * are packed into a single .notes section, which is mapped into the
     22 * PT_NOTE segment.  Because notes for a given name are grouped into
     23 * the same section, they'll all be adjacent the output file.
     24 *
     25 * This file defines macros for both C and assembler use.  Their
     26 * syntax is slightly different, but they're semantically similar.
     27 *
     28 * See the ELF specification for more detail about ELF notes.
     29 */
     30
     31#ifdef __ASSEMBLER__
     32/*
     33 * Generate a structure with the same shape as Elf{32,64}_Nhdr (which
     34 * turn out to be the same size and shape), followed by the name and
     35 * desc data with appropriate padding.  The 'desctype' argument is the
     36 * assembler pseudo op defining the type of the data e.g. .asciz while
     37 * 'descdata' is the data itself e.g.  "hello, world".
     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				;	\
     481:.asciz #name				;	\
     492:.balign 4				;	\
     503:
     51
     52#define ELFNOTE_END				\
     534484:.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 the shape of
     65 * Elf{32,64}_Nhdr, but includes the name and desc data.  The size and
     66 * type of name and desc depend on the macro arguments.  "name" must
     67 * be a literal string, and "desc" must be passed by value.  You may
     68 * only define one note per line, since __LINE__ is used to generate
     69 * unique symbols.
     70 */
     71#define _ELFNOTE_PASTE(a,b)	a##b
     72#define _ELFNOTE(size, name, unique, type, desc)			\
     73	static const struct {						\
     74		struct elf##size##_note _nhdr;				\
     75		unsigned char _name[sizeof(name)]			\
     76		__attribute__((aligned(sizeof(Elf##size##_Word))));	\
     77		typeof(desc) _desc					\
     78			     __attribute__((aligned(sizeof(Elf##size##_Word)))); \
     79	} _ELFNOTE_PASTE(_note_, unique)				\
     80		__used							\
     81		__attribute__((section(".note." name),			\
     82			       aligned(sizeof(Elf##size##_Word)),	\
     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, desc)
     94
     95#define ELFNOTE32(name, type, desc) ELFNOTE(32, name, type, desc)
     96#define ELFNOTE64(name, type, desc) ELFNOTE(64, name, type, desc)
     97#endif	/* __ASSEMBLER__ */
     98
     99#endif /* _LINUX_ELFNOTE_H */