mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 12:43:55 +08:00
441ff855f3
The byte order functions are visible to userspace. Unfortunately, __arch_swab32() contains an assembly instruction which is invalid when compiling for Thumb. This reverts to the C version when compiling for Thumb. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
59 lines
1.4 KiB
C
59 lines
1.4 KiB
C
/*
|
|
* linux/include/asm-arm/byteorder.h
|
|
*
|
|
* ARM Endian-ness. In little endian mode, the data bus is connected such
|
|
* that byte accesses appear as:
|
|
* 0 = d0...d7, 1 = d8...d15, 2 = d16...d23, 3 = d24...d31
|
|
* and word accesses (data or instruction) appear as:
|
|
* d0...d31
|
|
*
|
|
* When in big endian mode, byte accesses appear as:
|
|
* 0 = d24...d31, 1 = d16...d23, 2 = d8...d15, 3 = d0...d7
|
|
* and word accesses (data or instruction) appear as:
|
|
* d0...d31
|
|
*/
|
|
#ifndef __ASM_ARM_BYTEORDER_H
|
|
#define __ASM_ARM_BYTEORDER_H
|
|
|
|
#include <linux/compiler.h>
|
|
#include <asm/types.h>
|
|
|
|
static inline __attribute_const__ __u32 ___arch__swab32(__u32 x)
|
|
{
|
|
__u32 t;
|
|
|
|
#ifndef __thumb__
|
|
if (!__builtin_constant_p(x)) {
|
|
/*
|
|
* The compiler needs a bit of a hint here to always do the
|
|
* right thing and not screw it up to different degrees
|
|
* depending on the gcc version.
|
|
*/
|
|
asm ("eor\t%0, %1, %1, ror #16" : "=r" (t) : "r" (x));
|
|
} else
|
|
#endif
|
|
t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */
|
|
|
|
x = (x << 24) | (x >> 8); /* mov r0,r0,ror #8 */
|
|
t &= ~0x00FF0000; /* bic r1,r1,#0x00FF0000 */
|
|
x ^= (t >> 8); /* eor r0,r0,r1,lsr #8 */
|
|
|
|
return x;
|
|
}
|
|
|
|
#define __arch__swab32(x) ___arch__swab32(x)
|
|
|
|
#if !defined(__STRICT_ANSI__) || defined(__KERNEL__)
|
|
# define __BYTEORDER_HAS_U64__
|
|
# define __SWAB_64_THRU_32__
|
|
#endif
|
|
|
|
#ifdef __ARMEB__
|
|
#include <linux/byteorder/big_endian.h>
|
|
#else
|
|
#include <linux/byteorder/little_endian.h>
|
|
#endif
|
|
|
|
#endif
|
|
|