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#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

 *

 * Copy from userspace and compute checksum.  If we catch an exception

 * then zero the rest of the buffer.

 */

extern inline unsigned int

csum_partial_copy_from_user (const char *src, char *dst,

                                          int len, unsigned int 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);

}

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 */