609a70ac92
ip_fast_csum() requires a memory clobber on its inline asm as it accesses memory in a fashion that gcc can't predict. The GCC manual says: If your assembler instructions access memory in an unpredictable fashion, add `memory' to the list of clobbered registers. This will cause GCC to not keep memory values cached in registers across the assembler instruction and not optimize stores or loads to that memory. The bug hasn't been noticed in FRV, but it has been seen in PA-RISC. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
180 lines
4.6 KiB
C
180 lines
4.6 KiB
C
/* checksum.h: FRV checksumming
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*
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* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _ASM_CHECKSUM_H
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#define _ASM_CHECKSUM_H
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#include <linux/in6.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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__wsum csum_partial(const void *buff, int len, __wsum sum);
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/*
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* the same as csum_partial, but copies from src while it
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* checksums
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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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__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
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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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extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
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int len, __wsum sum, int *csum_err);
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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
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__sum16 ip_fast_csum(const void *iph, unsigned int ihl)
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{
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unsigned int tmp, inc, sum = 0;
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asm(" addcc gr0,gr0,gr0,icc0\n" /* clear icc0.C */
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" subi %1,#4,%1 \n"
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"0: \n"
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" ldu.p @(%1,%3),%4 \n"
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" subicc %2,#1,%2,icc1 \n"
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" addxcc.p %4,%0,%0,icc0 \n"
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" bhi icc1,#2,0b \n"
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/* fold the 33-bit result into 16-bits */
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" addxcc gr0,%0,%0,icc0 \n"
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" srli %0,#16,%1 \n"
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" sethi #0,%0 \n"
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" add %1,%0,%0 \n"
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" srli %0,#16,%1 \n"
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" add %1,%0,%0 \n"
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: "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (inc), "=&r"(tmp)
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: "0" (sum), "1" (iph), "2" (ihl), "3" (4),
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"m"(*(volatile struct { int _[100]; } *)iph)
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: "icc0", "icc1", "memory"
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);
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return (__force __sum16)~sum;
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}
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/*
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* Fold a partial checksum
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*/
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static inline __sum16 csum_fold(__wsum sum)
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{
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unsigned int tmp;
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asm(" srli %0,#16,%1 \n"
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" sethi #0,%0 \n"
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" add %1,%0,%0 \n"
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" srli %0,#16,%1 \n"
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" add %1,%0,%0 \n"
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: "=r"(sum), "=&r"(tmp)
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: "0"(sum)
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);
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return (__force __sum16)~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 __wsum
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csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
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unsigned short proto, __wsum sum)
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{
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asm(" addcc %1,%0,%0,icc0 \n"
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" addxcc %2,%0,%0,icc0 \n"
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" addxcc %3,%0,%0,icc0 \n"
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" addxcc gr0,%0,%0,icc0 \n"
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: "=r" (sum)
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: "r" (daddr), "r" (saddr), "r" (len + proto), "0"(sum)
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: "icc0"
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);
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return sum;
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}
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static inline __sum16
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csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,
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unsigned short proto, __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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extern __sum16 ip_compute_csum(const void *buff, int len);
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#define _HAVE_ARCH_IPV6_CSUM
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static inline __sum16
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csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
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__u32 len, unsigned short proto, __wsum sum)
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{
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unsigned long tmp, tmp2;
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asm(" addcc %2,%0,%0,icc0 \n"
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/* add up the source addr */
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" ldi @(%3,0),%1 \n"
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" addxcc %1,%0,%0,icc0 \n"
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" ldi @(%3,4),%2 \n"
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" addxcc %2,%0,%0,icc0 \n"
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" ldi @(%3,8),%1 \n"
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" addxcc %1,%0,%0,icc0 \n"
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" ldi @(%3,12),%2 \n"
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" addxcc %2,%0,%0,icc0 \n"
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/* add up the dest addr */
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" ldi @(%4,0),%1 \n"
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" addxcc %1,%0,%0,icc0 \n"
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" ldi @(%4,4),%2 \n"
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" addxcc %2,%0,%0,icc0 \n"
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" ldi @(%4,8),%1 \n"
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" addxcc %1,%0,%0,icc0 \n"
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" ldi @(%4,12),%2 \n"
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" addxcc %2,%0,%0,icc0 \n"
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/* fold the 33-bit result into 16-bits */
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" addxcc gr0,%0,%0,icc0 \n"
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" srli %0,#16,%1 \n"
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" sethi #0,%0 \n"
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" add %1,%0,%0 \n"
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" srli %0,#16,%1 \n"
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" add %1,%0,%0 \n"
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: "=r" (sum), "=&r" (tmp), "=r" (tmp2)
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: "r" (saddr), "r" (daddr), "0" (sum), "2" (len + proto)
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: "icc0"
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);
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return (__force __sum16)~sum;
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}
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#endif /* _ASM_CHECKSUM_H */
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