1/* SPDX-License-Identifier: GPL-2.0-or-later */
2#ifndef _OBJTOOL_ENDIANNESS_H
3#define _OBJTOOL_ENDIANNESS_H
4
5#include <linux/kernel.h>
6#include <endian.h>
7#include <objtool/elf.h>
8
9/*
10 * Does a byte swap if target file endianness doesn't match the host, i.e. cross
11 * compilation for little endian on big endian and vice versa.
12 * To be used for multi-byte values conversion, which are read from / about
13 * to be written to a target native endianness ELF file.
14 */
15static inline bool need_bswap(struct elf *elf)
16{
17	return (__BYTE_ORDER == __LITTLE_ENDIAN) ^
18	       (elf->ehdr.e_ident[EI_DATA] == ELFDATA2LSB);
19}
20
21#define bswap_if_needed(elf, val)					\
22({									\
23	__typeof__(val) __ret;						\
24	bool __need_bswap = need_bswap(elf);				\
25	switch (sizeof(val)) {						\
26	case 8:								\
27		__ret = __need_bswap ? bswap_64(val) : (val); break;	\
28	case 4:								\
29		__ret = __need_bswap ? bswap_32(val) : (val); break;	\
30	case 2:								\
31		__ret = __need_bswap ? bswap_16(val) : (val); break;	\
32	default:							\
33		BUILD_BUG(); break;					\
34	}								\
35	__ret;								\
36})
37
38#endif /* _OBJTOOL_ENDIANNESS_H */
39