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kernel
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linux
[ARM] Fix byte order macros for Thumb
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>
authored by
H. Peter Anvin
and committed by
Russell King
441ff855
5e642387
+6
-4
+6
-4
include/asm-arm/byteorder.h
+6
-4
include/asm-arm/byteorder.h
···
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{
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__u32 t;
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-
if (__builtin_constant_p(x)) {
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t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */
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-
} else {
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+
#ifndef __thumb__
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if (!__builtin_constant_p(x)) {
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/*
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* The compiler needs a bit of a hint here to always do the
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* right thing and not screw it up to different degrees
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* depending on the gcc version.
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*/
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asm ("eor\t%0, %1, %1, ror #16" : "=r" (t) : "r" (x));
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}
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} else
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#endif
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t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */
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+
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x = (x << 24) | (x >> 8); /* mov r0,r0,ror #8 */
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t &= ~0x00FF0000; /* bic r1,r1,#0x00FF0000 */
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x ^= (t >> 8); /* eor r0,r0,r1,lsr #8 */