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Diffstat (limited to 'arch/s390/include/asm/checksum.h')
| -rw-r--r-- | arch/s390/include/asm/checksum.h | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/arch/s390/include/asm/checksum.h b/arch/s390/include/asm/checksum.h new file mode 100644 index 000000000000..d5a8e7c1477c --- /dev/null +++ b/arch/s390/include/asm/checksum.h @@ -0,0 +1,166 @@ +#ifndef _S390_CHECKSUM_H +#define _S390_CHECKSUM_H + +/* + * include/asm-s390/checksum.h + * S390 fast network checksum routines + * see also arch/S390/lib/checksum.c + * + * S390 version + * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation + * Author(s): Ulrich Hild (first version) + * Martin Schwidefsky (heavily optimized CKSM version) + * D.J. Barrow (third attempt) + */ + +#include <asm/uaccess.h> + +/* + * computes the checksum of a memory block at buff, length len, + * and adds in "sum" (32-bit) + * + * returns a 32-bit number suitable for feeding into itself + * or csum_tcpudp_magic + * + * this function must be called with even lengths, except + * for the last fragment, which may be odd + * + * it's best to have buff aligned on a 32-bit boundary + */ +static inline __wsum +csum_partial(const void *buff, int len, __wsum sum) +{ + register unsigned long reg2 asm("2") = (unsigned long) buff; + register unsigned long reg3 asm("3") = (unsigned long) len; + + asm volatile( + "0: cksm %0,%1\n" /* do checksum on longs */ + " jo 0b\n" + : "+d" (sum), "+d" (reg2), "+d" (reg3) : : "cc", "memory"); + return sum; +} + +/* + * the same as csum_partial_copy, but copies from user space. + * + * here even more important to align src and dst on a 32-bit (or even + * better 64-bit) boundary + * + * Copy from userspace and compute checksum. If we catch an exception + * then zero the rest of the buffer. + */ +static inline __wsum +csum_partial_copy_from_user(const void __user *src, void *dst, + int len, __wsum sum, + int *err_ptr) +{ + int missing; + + missing = copy_from_user(dst, src, len); + if (missing) { + memset(dst + len - missing, 0, missing); + *err_ptr = -EFAULT; + } + + return csum_partial(dst, len, sum); +} + + +static inline __wsum +csum_partial_copy_nocheck (const void *src, void *dst, int len, __wsum sum) +{ + memcpy(dst,src,len); + return csum_partial(dst, len, sum); +} + +/* + * Fold a partial checksum without adding pseudo headers + */ +static inline __sum16 csum_fold(__wsum sum) +{ +#ifndef __s390x__ + register_pair rp; + + 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; +} + +/* + * This is a version of ip_compute_csum() optimized for IP headers, + * which always checksum on 4 octet boundaries. + * + */ +static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) +{ + return csum_fold(csum_partial(iph, ihl*4, 0)); +} + +/* + * computes the checksum of the TCP/UDP pseudo-header + * returns a 32-bit checksum + */ +static inline __wsum +csum_tcpudp_nofold(__be32 saddr, __be32 daddr, + unsigned short len, unsigned short proto, + __wsum sum) +{ + __u32 csum = (__force __u32)sum; + + csum += (__force __u32)saddr; + if (csum < (__force __u32)saddr) + csum++; + + csum += (__force __u32)daddr; + if (csum < (__force __u32)daddr) + csum++; + + csum += len + proto; + if (csum < len + proto) + csum++; + + return (__force __wsum)csum; +} + +/* + * computes the checksum of the TCP/UDP pseudo-header + * returns a 16-bit checksum, already complemented + */ + +static inline __sum16 +csum_tcpudp_magic(__be32 saddr, __be32 daddr, + unsigned short len, unsigned short proto, + __wsum sum) +{ + return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); +} + +/* + * this routine is used for miscellaneous IP-like checksums, mainly + * in icmp.c + */ + +static inline __sum16 ip_compute_csum(const void *buff, int len) +{ + return csum_fold(csum_partial(buff, len, 0)); +} + +#endif /* _S390_CHECKSUM_H */ + + |