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checksum.h
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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
*/
static inline unsigned int
csum_partial(const unsigned char * buff, int len, unsigned int sum)
{
/*
* Experiments with ethernet and slip connections show that buf
* is aligned on either a 2-byte or 4-byte boundary.
*/
#ifndef __s390x__
register_pair rp;
rp.subreg.even = (unsigned long) buff;
rp.subreg.odd = (unsigned long) len;
__asm__ __volatile__ (
"0: cksm %0,%1\n" /* do checksum on longs */
" jo 0b\n"
: "+&d" (sum), "+&a" (rp) : : "cc", "memory" );
#else /* __s390x__ */
__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", "memory", "2", "3" );
#endif /* __s390x__ */
return sum;
}
/*
* csum_partial as an inline function
*/
static inline unsigned int
csum_partial_inline(const unsigned char * buff, int len, unsigned int sum)
{
#ifndef __s390x__
register_pair rp;
rp.subreg.even = (unsigned long) buff;
rp.subreg.odd = (unsigned long) len;
__asm__ __volatile__ (
"0: cksm %0,%1\n" /* do checksum on longs */
" jo 0b\n"
: "+&d" (sum), "+&a" (rp) : : "cc", "memory" );
#else /* __s390x__ */
__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", "memory", "2", "3" );
#endif /* __s390x__ */
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 unsigned int
csum_partial_copy_from_user(const char __user *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);
}
static 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
*/
static inline unsigned short
csum_fold(unsigned int 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, 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");
#endif /* __s390x__ */
return ((unsigned short) ~sum);
}
/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksum on 4 octet boundaries.
*
*/
static inline unsigned short
ip_fast_csum(unsigned char *iph, unsigned int ihl)
{
unsigned long sum;
#ifndef __s390x__
register_pair rp;
rp.subreg.even = (unsigned long) iph;
rp.subreg.odd = (unsigned long) ihl*4;
__asm__ __volatile__ (
" sr %0,%0\n" /* set sum to zero */
"0: cksm %0,%1\n" /* do checksum on longs */
" jo 0b\n"
: "=&d" (sum), "+&a" (rp) : : "cc", "memory" );
#else /* __s390x__ */
__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", "memory", "2", "3" );
#endif /* __s390x__ */
return csum_fold(sum);
}
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 32-bit checksum
*/
static inline unsigned int
csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr,
unsigned short len, unsigned short proto,
unsigned int sum)
{
#ifndef __s390x__
__asm__ __volatile__ (
" alr %0,%1\n" /* sum += saddr */
" brc 12,0f\n"
" ahi %0,1\n" /* add carry */
"0:"
: "+&d" (sum) : "d" (saddr) : "cc" );
__asm__ __volatile__ (
" alr %0,%1\n" /* sum += daddr */
" brc 12,1f\n"
" ahi %0,1\n" /* add carry */
"1:"
: "+&d" (sum) : "d" (daddr) : "cc" );
__asm__ __volatile__ (
" alr %0,%1\n" /* sum += (len<<16) + (proto<<8) */
" brc 12,2f\n"
" ahi %0,1\n" /* add carry */
"2:"
: "+&d" (sum)
: "d" (((unsigned int) len<<16) + (unsigned int) proto)
: "cc" );
#else /* __s390x__ */
__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" );
#endif /* __s390x__ */
return sum;
}
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 16-bit checksum, already complemented
*/
static 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
*/
static inline unsigned short
ip_compute_csum(unsigned char * buff, int len)
{
return csum_fold(csum_partial(buff, len, 0));
}
#endif /* _S390_CHECKSUM_H */