tools/objtool/include/objtool/endianness.h

Source file repositories/reference/linux-study-clean/tools/objtool/include/objtool/endianness.h

File Facts

System
Linux kernel
Corpus path
tools/objtool/include/objtool/endianness.h
Extension
.h
Size
1086 bytes
Lines
38
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef _OBJTOOL_ENDIANNESS_H
#define _OBJTOOL_ENDIANNESS_H

#include <linux/kernel.h>
#include <endian.h>

/*
 * Does a byte swap if target file endianness doesn't match the host, i.e. cross
 * compilation for little endian on big endian and vice versa.
 * To be used for multi-byte values conversion, which are read from / about
 * to be written to a target native endianness ELF file.
 */
static inline bool need_bswap(GElf_Ehdr *ehdr)
{
	return (__BYTE_ORDER == __LITTLE_ENDIAN) ^
	       (ehdr->e_ident[EI_DATA] == ELFDATA2LSB);
}

#define __bswap_if_needed(ehdr, val)					\
({									\
	__typeof__(val) __ret;						\
	bool __need_bswap = need_bswap(ehdr);				\
	switch (sizeof(val)) {						\
	case 8:								\
		__ret = __need_bswap ? bswap_64(val) : (val); break;	\
	case 4:								\
		__ret = __need_bswap ? bswap_32(val) : (val); break;	\
	case 2:								\
		__ret = __need_bswap ? bswap_16(val) : (val); break;	\
	default:							\
		BUILD_BUG(); break;					\
	}								\
	__ret;								\
})

#endif /* _OBJTOOL_ENDIANNESS_H */

Annotation

Implementation Notes