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Diffstat (limited to 'include/asm-s390x/checksum.h')
| -rw-r--r-- | include/asm-s390x/checksum.h | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/include/asm-s390x/checksum.h b/include/asm-s390x/checksum.h new file mode 100644 index 000000000..bb825c546 --- /dev/null +++ b/include/asm-s390x/checksum.h @@ -0,0 +1,188 @@ +#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 + */ +unsigned int +csum_partial(const unsigned char * buff, int len, unsigned int sum); + +/* + * csum_partial as an inline function + */ +extern inline unsigned int +csum_partial_inline(const unsigned char * buff, int len, unsigned int sum) +{ + __asm__ __volatile__ ( + " lgr 2,%1\n" /* address in gpr 2 */ + " lgfr 3,%2\n" /* length in gpr 3 */ + "0: cksm %0,2\n" /* do checksum on longs */ + " jo 0b\n" + : "+&d" (sum) + : "d" (buff), "d" (len) + : "cc", "2", "3" ); + return sum; +} + +/* + * the same as csum_partial, but copies from src while it + * checksums + * + * here even more important to align src and dst on a 32-bit (or even + * better 64-bit) boundary + */ + +extern inline unsigned int +csum_partial_copy(const char *src, char *dst, int len,unsigned int sum) +{ + memcpy(dst,src,len); + return csum_partial_inline(dst, len, 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 + */ + +extern inline unsigned int +csum_partial_copy_from_user(const char *src, char *dst, + int len, unsigned int sum, int *errp) +{ + if (copy_from_user(dst, src, len)) { + *errp = -EFAULT; + memset(dst, 0, len); + return sum; + } + return csum_partial_inline(dst, len, sum); +} + +extern inline unsigned int +csum_partial_copy_nocheck (const char *src, char *dst, int len, unsigned int sum) +{ + memcpy(dst,src,len); + return csum_partial_inline(dst, len, sum); +} + +/* + * Fold a partial checksum without adding pseudo headers + */ +extern inline unsigned short +csum_fold(unsigned int sum) +{ + __asm__ __volatile__ ( + " sr 3,3\n" /* %0 = H*65536 + L */ + " lr 2,%0\n" /* %0 = H L, R2/R3 = H L / 0 0 */ + " srdl 2,16\n" /* %0 = H L, R2/R3 = 0 H / L 0 */ + " alr 2,3\n" /* %0 = H L, R2/R3 = 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"); + return ((unsigned short) ~sum); +} + +/* + * This is a version of ip_compute_csum() optimized for IP headers, + * which always checksum on 4 octet boundaries. + * + */ +extern inline unsigned short +ip_fast_csum(unsigned char *iph, unsigned int ihl) +{ + unsigned long sum; + + __asm__ __volatile__ ( + " slgr %0,%0\n" /* set sum to zero */ + " lgr 2,%1\n" /* address in gpr 2 */ + " lgfr 3,%2\n" /* length in gpr 3 */ + "0: cksm %0,2\n" /* do checksum on ints */ + " jo 0b\n" + : "=&d" (sum) + : "d" (iph), "d" (ihl*4) + : "cc", "2", "3" ); + return csum_fold(sum); +} + +/* + * computes the checksum of the TCP/UDP pseudo-header + * returns a 32-bit checksum + */ +extern inline unsigned int +csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, + unsigned short len, unsigned short proto, + unsigned int sum) +{ + __asm__ __volatile__ ( + " lgfr %0,%0\n" + " algr %0,%1\n" /* sum += saddr */ + " brc 12,0f\n" + " aghi %0,1\n" /* add carry */ + "0: algr %0,%2\n" /* sum += daddr */ + " brc 12,1f\n" + " aghi %0,1\n" /* add carry */ + "1: algfr %0,%3\n" /* sum += (len<<16) + proto */ + " brc 12,2f\n" + " aghi %0,1\n" /* add carry */ + "2: srlg 0,%0,32\n" + " alr %0,0\n" /* fold to 32 bits */ + " brc 12,3f\n" + " ahi %0,1\n" /* add carry */ + "3: llgfr %0,%0" + : "+&d" (sum) + : "d" (saddr), "d" (daddr), + "d" (((unsigned int) len<<16) + (unsigned int) proto) + : "cc", "0" ); + return sum; +} + +/* + * computes the checksum of the TCP/UDP pseudo-header + * returns a 16-bit checksum, already complemented + */ + +extern inline unsigned short int +csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, + unsigned short len, unsigned short proto, + unsigned int 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 + */ + +extern inline unsigned short +ip_compute_csum(unsigned char * buff, int len) +{ + return csum_fold(csum_partial_inline(buff, len, 0)); +} + +#endif /* _S390_CHECKSUM_H */ + + |