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afbc1e994d
git commit f994aae1bd changed the
function declaration of csum_tcpudp_nofold. Argument types were
changed from unsigned long to __be32 (unsigned int). Therefore we
lost the implicit type conversion that zeroed the upper half of the
registers that are used to pass parameters. Since the inline assembly
relied on this we ended up adding random values and wrong checksums
were created.
Showed only up on machines with more than 4GB since gcc produced code
where the registers that are used to pass 'saddr' and 'daddr' previously
contained addresses before calling this function.
Fix this by using 32 bit arithmetics and convert code to C, since gcc
produces better code than these hand-optimized versions.
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
167 lines
4.1 KiB
C
167 lines
4.1 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 __wsum
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csum_partial(const void *buff, int len, __wsum sum)
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{
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register unsigned long reg2 asm("2") = (unsigned long) buff;
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register unsigned long reg3 asm("3") = (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), "+d" (reg2), "+d" (reg3) : : "cc", "memory");
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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 __wsum
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csum_partial_copy_from_user(const void __user *src, void *dst,
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int len, __wsum 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 __wsum
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csum_partial_copy_nocheck (const void *src, void *dst, int len, __wsum sum)
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{
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memcpy(dst,src,len);
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return csum_partial(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 __sum16 csum_fold(__wsum 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, 2/3 = H L / 0 0 */
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" srdl 2,16\n" /* %0 = H L, 2/3 = 0 H / L 0 */
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" alr 2,3\n" /* %0 = H L, 2/3 = 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 (__force __sum16) ~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 __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
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{
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return csum_fold(csum_partial(iph, ihl*4, 0));
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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 __wsum
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csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
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unsigned short len, unsigned short proto,
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__wsum sum)
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{
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__u32 csum = (__force __u32)sum;
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csum += (__force __u32)saddr;
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if (csum < (__force __u32)saddr)
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csum++;
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csum += (__force __u32)daddr;
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if (csum < (__force __u32)daddr)
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csum++;
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csum += len + proto;
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if (csum < len + proto)
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csum++;
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return (__force __wsum)csum;
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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 __sum16
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csum_tcpudp_magic(__be32 saddr, __be32 daddr,
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unsigned short len, unsigned short proto,
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__wsum 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 __sum16 ip_compute_csum(const void *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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