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Diffstat (limited to 'arch/s390/include/asm/checksum.h')
-rw-r--r--arch/s390/include/asm/checksum.h25
1 files changed, 4 insertions, 21 deletions
diff --git a/arch/s390/include/asm/checksum.h b/arch/s390/include/asm/checksum.h
index d5a8e7c1477..6c00f6800a3 100644
--- a/arch/s390/include/asm/checksum.h
+++ b/arch/s390/include/asm/checksum.h
@@ -78,28 +78,11 @@ csum_partial_copy_nocheck (const void *src, void *dst, int len, __wsum sum)
*/
static inline __sum16 csum_fold(__wsum sum)
{
-#ifndef __s390x__
- register_pair rp;
+ u32 csum = (__force u32) sum;
- asm volatile(
- " slr %N1,%N1\n" /* %0 = H L */
- " lr %1,%0\n" /* %0 = H L, %1 = H L 0 0 */
- " srdl %1,16\n" /* %0 = H L, %1 = 0 H L 0 */
- " alr %1,%N1\n" /* %0 = H L, %1 = L H L 0 */
- " alr %0,%1\n" /* %0 = H+L+C L+H */
- " srl %0,16\n" /* %0 = H+L+C */
- : "+&d" (sum), "=d" (rp) : : "cc");
-#else /* __s390x__ */
- asm volatile(
- " sr 3,3\n" /* %0 = H*65536 + L */
- " lr 2,%0\n" /* %0 = H L, 2/3 = H L / 0 0 */
- " srdl 2,16\n" /* %0 = H L, 2/3 = 0 H / L 0 */
- " alr 2,3\n" /* %0 = H L, 2/3 = L H / L 0 */
- " alr %0,2\n" /* %0 = H+L+C L+H */
- " srl %0,16\n" /* %0 = H+L+C */
- : "+&d" (sum) : : "cc", "2", "3");
-#endif /* __s390x__ */
- return (__force __sum16) ~sum;
+ csum += (csum >> 16) + (csum << 16);
+ csum >>= 16;
+ return (__force __sum16) ~csum;
}
/*