tools/objtool/include/objtool/endianness.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 #ifndef _OBJTOOL_ENDIANNESS_H
   3 #define _OBJTOOL_ENDIANNESS_H
   4
   5 #include <arch/endianness.h>
   6 #include <linux/kernel.h>
   7 #include <endian.h>
   8
   9 #ifndef __TARGET_BYTE_ORDER
  10 #error undefined arch __TARGET_BYTE_ORDER
  11 #endif
  12
  13 #if __BYTE_ORDER != __TARGET_BYTE_ORDER
  14 #define __NEED_BSWAP 1
  15 #else
  16 #define __NEED_BSWAP 0
  17 #endif
  18
  19 /*
  20  * Does a byte swap if target endianness doesn't match the host, i.e. cross
  21  * compilation for little endian on big endian and vice versa.
  22  * To be used for multi-byte values conversion, which are read from / about
  23  * to be written to a target native endianness ELF file.
  24  */
  25 #define bswap_if_needed(val)                                            \
  26 ({                                                                      \
  27         __typeof__(val) __ret;                                          \
  28         switch (sizeof(val)) {                                          \
  29         case 8: __ret = __NEED_BSWAP ? bswap_64(val) : (val); break;    \
  30         case 4: __ret = __NEED_BSWAP ? bswap_32(val) : (val); break;    \
  31         case 2: __ret = __NEED_BSWAP ? bswap_16(val) : (val); break;    \
  32         default:                                                        \
  33                 BUILD_BUG(); break;                                     \
  34         }                                                               \
  35         __ret;                                                          \
  36 })
  37
  38 #endif /* _OBJTOOL_ENDIANNESS_H */