1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
264 lines
7.6 KiB
C
264 lines
7.6 KiB
C
#ifndef _S390_CHECKSUM_H
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#define _S390_CHECKSUM_H
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/*
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* include/asm-s390/checksum.h
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* S390 fast network checksum routines
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* see also arch/S390/lib/checksum.c
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*
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* S390 version
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* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
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* Author(s): Ulrich Hild (first version)
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* Martin Schwidefsky (heavily optimized CKSM version)
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* D.J. Barrow (third attempt)
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*/
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#include <asm/uaccess.h>
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/*
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* computes the checksum of a memory block at buff, length len,
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* and adds in "sum" (32-bit)
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*
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* returns a 32-bit number suitable for feeding into itself
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* or csum_tcpudp_magic
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*
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* this function must be called with even lengths, except
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* for the last fragment, which may be odd
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*
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* it's best to have buff aligned on a 32-bit boundary
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*/
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static inline unsigned int
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csum_partial(const unsigned char * buff, int len, unsigned int sum)
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{
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/*
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* Experiments with ethernet and slip connections show that buf
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* is aligned on either a 2-byte or 4-byte boundary.
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*/
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#ifndef __s390x__
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register_pair rp;
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rp.subreg.even = (unsigned long) buff;
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rp.subreg.odd = (unsigned long) len;
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__asm__ __volatile__ (
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"0: cksm %0,%1\n" /* do checksum on longs */
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" jo 0b\n"
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: "+&d" (sum), "+&a" (rp) : : "cc", "memory" );
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#else /* __s390x__ */
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__asm__ __volatile__ (
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" lgr 2,%1\n" /* address in gpr 2 */
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" lgfr 3,%2\n" /* length in gpr 3 */
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"0: cksm %0,2\n" /* do checksum on longs */
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" jo 0b\n"
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: "+&d" (sum)
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: "d" (buff), "d" (len)
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: "cc", "memory", "2", "3" );
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#endif /* __s390x__ */
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return sum;
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}
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/*
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* csum_partial as an inline function
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*/
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static inline unsigned int
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csum_partial_inline(const unsigned char * buff, int len, unsigned int sum)
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{
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#ifndef __s390x__
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register_pair rp;
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rp.subreg.even = (unsigned long) buff;
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rp.subreg.odd = (unsigned long) len;
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__asm__ __volatile__ (
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"0: cksm %0,%1\n" /* do checksum on longs */
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" jo 0b\n"
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: "+&d" (sum), "+&a" (rp) : : "cc", "memory" );
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#else /* __s390x__ */
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__asm__ __volatile__ (
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" lgr 2,%1\n" /* address in gpr 2 */
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" lgfr 3,%2\n" /* length in gpr 3 */
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"0: cksm %0,2\n" /* do checksum on longs */
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" jo 0b\n"
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: "+&d" (sum)
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: "d" (buff), "d" (len)
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: "cc", "memory", "2", "3" );
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#endif /* __s390x__ */
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return sum;
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}
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/*
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* the same as csum_partial_copy, but copies from user space.
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*
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* here even more important to align src and dst on a 32-bit (or even
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* better 64-bit) boundary
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*
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* Copy from userspace and compute checksum. If we catch an exception
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* then zero the rest of the buffer.
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*/
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static inline unsigned int
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csum_partial_copy_from_user(const char __user *src, char *dst,
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int len, unsigned int sum,
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int *err_ptr)
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{
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int missing;
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missing = copy_from_user(dst, src, len);
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if (missing) {
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memset(dst + len - missing, 0, missing);
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*err_ptr = -EFAULT;
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}
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return csum_partial(dst, len, sum);
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}
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static inline unsigned int
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csum_partial_copy_nocheck (const char *src, char *dst, int len, unsigned int sum)
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{
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memcpy(dst,src,len);
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return csum_partial_inline(dst, len, sum);
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}
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/*
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* Fold a partial checksum without adding pseudo headers
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*/
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static inline unsigned short
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csum_fold(unsigned int sum)
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{
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#ifndef __s390x__
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register_pair rp;
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__asm__ __volatile__ (
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" slr %N1,%N1\n" /* %0 = H L */
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" lr %1,%0\n" /* %0 = H L, %1 = H L 0 0 */
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" srdl %1,16\n" /* %0 = H L, %1 = 0 H L 0 */
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" alr %1,%N1\n" /* %0 = H L, %1 = L H L 0 */
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" alr %0,%1\n" /* %0 = H+L+C L+H */
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" srl %0,16\n" /* %0 = H+L+C */
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: "+&d" (sum), "=d" (rp) : : "cc" );
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#else /* __s390x__ */
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__asm__ __volatile__ (
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" sr 3,3\n" /* %0 = H*65536 + L */
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" lr 2,%0\n" /* %0 = H L, R2/R3 = H L / 0 0 */
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" srdl 2,16\n" /* %0 = H L, R2/R3 = 0 H / L 0 */
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" alr 2,3\n" /* %0 = H L, R2/R3 = L H / L 0 */
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" alr %0,2\n" /* %0 = H+L+C L+H */
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" srl %0,16\n" /* %0 = H+L+C */
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: "+&d" (sum) : : "cc", "2", "3");
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#endif /* __s390x__ */
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return ((unsigned short) ~sum);
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}
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/*
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* This is a version of ip_compute_csum() optimized for IP headers,
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* which always checksum on 4 octet boundaries.
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*
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*/
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static inline unsigned short
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ip_fast_csum(unsigned char *iph, unsigned int ihl)
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{
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unsigned long sum;
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#ifndef __s390x__
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register_pair rp;
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rp.subreg.even = (unsigned long) iph;
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rp.subreg.odd = (unsigned long) ihl*4;
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__asm__ __volatile__ (
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" sr %0,%0\n" /* set sum to zero */
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"0: cksm %0,%1\n" /* do checksum on longs */
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" jo 0b\n"
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: "=&d" (sum), "+&a" (rp) : : "cc", "memory" );
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#else /* __s390x__ */
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__asm__ __volatile__ (
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" slgr %0,%0\n" /* set sum to zero */
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" lgr 2,%1\n" /* address in gpr 2 */
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" lgfr 3,%2\n" /* length in gpr 3 */
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"0: cksm %0,2\n" /* do checksum on ints */
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" jo 0b\n"
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: "=&d" (sum)
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: "d" (iph), "d" (ihl*4)
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: "cc", "memory", "2", "3" );
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#endif /* __s390x__ */
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return csum_fold(sum);
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}
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/*
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* computes the checksum of the TCP/UDP pseudo-header
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* returns a 32-bit checksum
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*/
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static inline unsigned int
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csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr,
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unsigned short len, unsigned short proto,
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unsigned int sum)
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{
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#ifndef __s390x__
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__asm__ __volatile__ (
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" alr %0,%1\n" /* sum += saddr */
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" brc 12,0f\n"
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" ahi %0,1\n" /* add carry */
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"0:"
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: "+&d" (sum) : "d" (saddr) : "cc" );
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__asm__ __volatile__ (
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" alr %0,%1\n" /* sum += daddr */
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" brc 12,1f\n"
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" ahi %0,1\n" /* add carry */
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"1:"
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: "+&d" (sum) : "d" (daddr) : "cc" );
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__asm__ __volatile__ (
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" alr %0,%1\n" /* sum += (len<<16) + (proto<<8) */
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" brc 12,2f\n"
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" ahi %0,1\n" /* add carry */
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"2:"
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: "+&d" (sum)
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: "d" (((unsigned int) len<<16) + (unsigned int) proto)
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: "cc" );
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#else /* __s390x__ */
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__asm__ __volatile__ (
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" lgfr %0,%0\n"
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" algr %0,%1\n" /* sum += saddr */
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" brc 12,0f\n"
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" aghi %0,1\n" /* add carry */
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"0: algr %0,%2\n" /* sum += daddr */
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" brc 12,1f\n"
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" aghi %0,1\n" /* add carry */
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"1: algfr %0,%3\n" /* sum += (len<<16) + proto */
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" brc 12,2f\n"
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" aghi %0,1\n" /* add carry */
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"2: srlg 0,%0,32\n"
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" alr %0,0\n" /* fold to 32 bits */
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" brc 12,3f\n"
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" ahi %0,1\n" /* add carry */
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"3: llgfr %0,%0"
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: "+&d" (sum)
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: "d" (saddr), "d" (daddr),
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"d" (((unsigned int) len<<16) + (unsigned int) proto)
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: "cc", "0" );
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#endif /* __s390x__ */
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return sum;
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}
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/*
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* computes the checksum of the TCP/UDP pseudo-header
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* returns a 16-bit checksum, already complemented
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*/
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static inline unsigned short int
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csum_tcpudp_magic(unsigned long saddr, unsigned long daddr,
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unsigned short len, unsigned short proto,
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unsigned int sum)
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{
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return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
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}
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/*
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* this routine is used for miscellaneous IP-like checksums, mainly
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* in icmp.c
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*/
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static inline unsigned short
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ip_compute_csum(unsigned char * buff, int len)
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{
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return csum_fold(csum_partial(buff, len, 0));
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}
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#endif /* _S390_CHECKSUM_H */
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