162306a36Sopenharmony_ci/* SPDX-License-Identifier: GPL-2.0-or-later */
262306a36Sopenharmony_ci#ifndef _OBJTOOL_ENDIANNESS_H
362306a36Sopenharmony_ci#define _OBJTOOL_ENDIANNESS_H
462306a36Sopenharmony_ci
562306a36Sopenharmony_ci#include <linux/kernel.h>
662306a36Sopenharmony_ci#include <endian.h>
762306a36Sopenharmony_ci#include <objtool/elf.h>
862306a36Sopenharmony_ci
962306a36Sopenharmony_ci/*
1062306a36Sopenharmony_ci * Does a byte swap if target file endianness doesn't match the host, i.e. cross
1162306a36Sopenharmony_ci * compilation for little endian on big endian and vice versa.
1262306a36Sopenharmony_ci * To be used for multi-byte values conversion, which are read from / about
1362306a36Sopenharmony_ci * to be written to a target native endianness ELF file.
1462306a36Sopenharmony_ci */
1562306a36Sopenharmony_cistatic inline bool need_bswap(struct elf *elf)
1662306a36Sopenharmony_ci{
1762306a36Sopenharmony_ci	return (__BYTE_ORDER == __LITTLE_ENDIAN) ^
1862306a36Sopenharmony_ci	       (elf->ehdr.e_ident[EI_DATA] == ELFDATA2LSB);
1962306a36Sopenharmony_ci}
2062306a36Sopenharmony_ci
2162306a36Sopenharmony_ci#define bswap_if_needed(elf, val)					\
2262306a36Sopenharmony_ci({									\
2362306a36Sopenharmony_ci	__typeof__(val) __ret;						\
2462306a36Sopenharmony_ci	bool __need_bswap = need_bswap(elf);				\
2562306a36Sopenharmony_ci	switch (sizeof(val)) {						\
2662306a36Sopenharmony_ci	case 8:								\
2762306a36Sopenharmony_ci		__ret = __need_bswap ? bswap_64(val) : (val); break;	\
2862306a36Sopenharmony_ci	case 4:								\
2962306a36Sopenharmony_ci		__ret = __need_bswap ? bswap_32(val) : (val); break;	\
3062306a36Sopenharmony_ci	case 2:								\
3162306a36Sopenharmony_ci		__ret = __need_bswap ? bswap_16(val) : (val); break;	\
3262306a36Sopenharmony_ci	default:							\
3362306a36Sopenharmony_ci		BUILD_BUG(); break;					\
3462306a36Sopenharmony_ci	}								\
3562306a36Sopenharmony_ci	__ret;								\
3662306a36Sopenharmony_ci})
3762306a36Sopenharmony_ci
3862306a36Sopenharmony_ci#endif /* _OBJTOOL_ENDIANNESS_H */
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