Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
powerpc: Use rol32() instead of opencoding in csum_fold()
rol32(x, 16) will do the rotate using rlwinm.
No need to open code using inline assembly.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/794337eff7bb803d2c4e67d9eee635390c4c48fe.1646812553.git.christophe.leroy@csgroup.eu
authored by
Christophe Leroy
and committed by
Michael Ellerman
a1ae4317
e6f6390a
+8
-7
+8
-7
arch/powerpc/include/asm/checksum.h
+8
-7
arch/powerpc/include/asm/checksum.h
···
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*/
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static inline __sum16 csum_fold(__wsum sum)
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{
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unsigned int tmp;
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u32 tmp = (__force u32)sum;
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/* swap the two 16-bit halves of sum */
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__asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
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/* if there is a carry from adding the two 16-bit halves,
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it will carry from the lower half into the upper half,
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giving us the correct sum in the upper half. */
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return (__force __sum16)(~((__force u32)sum + tmp) >> 16);
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/*
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* swap the two 16-bit halves of sum
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* if there is a carry from adding the two 16-bit halves,
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* it will carry from the lower half into the upper half,
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* giving us the correct sum in the upper half.
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*/
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return (__force __sum16)(~(tmp + rol32(tmp, 16)) >> 16);
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}
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static inline u32 from64to32(u64 x)