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![Bob Breuer](/assets/img/avatar_default.png)
In some cases such as: iph->check = 0; iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); GCC may optimize out the previous store. Observed as a failure of NFS over udp (bad checksums on ip fragments) when compiled with GCC 3.4.2. Signed-off-by: Bob Breuer <breuerr@mc.net> Signed-off-by: David S. Miller <davem@davemloft.net>
242 lines
6.7 KiB
C
242 lines
6.7 KiB
C
/* $Id: checksum.h,v 1.33 2002/02/01 22:01:05 davem Exp $ */
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#ifndef __SPARC_CHECKSUM_H
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#define __SPARC_CHECKSUM_H
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/* checksum.h: IP/UDP/TCP checksum routines on the Sparc.
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*
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* Copyright(C) 1995 Linus Torvalds
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* Copyright(C) 1995 Miguel de Icaza
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* Copyright(C) 1996 David S. Miller
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* Copyright(C) 1996 Eddie C. Dost
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* Copyright(C) 1997 Jakub Jelinek
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*
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* derived from:
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* Alpha checksum c-code
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* ix86 inline assembly
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* RFC1071 Computing the Internet Checksum
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*/
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#include <linux/in6.h>
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#include <asm/uaccess.h>
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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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extern __wsum csum_partial(const void *buff, int len, __wsum sum);
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/* the same as csum_partial, but copies from fs: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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extern unsigned int __csum_partial_copy_sparc_generic (const unsigned char *, unsigned char *);
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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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register unsigned int ret asm("o0") = (unsigned int)src;
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register char *d asm("o1") = dst;
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register int l asm("g1") = len;
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__asm__ __volatile__ (
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"call __csum_partial_copy_sparc_generic\n\t"
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" mov %6, %%g7\n"
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: "=&r" (ret), "=&r" (d), "=&r" (l)
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: "0" (ret), "1" (d), "2" (l), "r" (sum)
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: "o2", "o3", "o4", "o5", "o7",
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"g2", "g3", "g4", "g5", "g7",
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"memory", "cc");
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return (__force __wsum)ret;
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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, int len,
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__wsum sum, int *err)
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{
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register unsigned long ret asm("o0") = (unsigned long)src;
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register char *d asm("o1") = dst;
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register int l asm("g1") = len;
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register __wsum s asm("g7") = sum;
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__asm__ __volatile__ (
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".section __ex_table,#alloc\n\t"
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".align 4\n\t"
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".word 1f,2\n\t"
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".previous\n"
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"1:\n\t"
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"call __csum_partial_copy_sparc_generic\n\t"
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" st %8, [%%sp + 64]\n"
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: "=&r" (ret), "=&r" (d), "=&r" (l), "=&r" (s)
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: "0" (ret), "1" (d), "2" (l), "3" (s), "r" (err)
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: "o2", "o3", "o4", "o5", "o7", "g2", "g3", "g4", "g5",
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"cc", "memory");
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return (__force __wsum)ret;
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}
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static inline __wsum
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csum_partial_copy_to_user(const void *src, void __user *dst, int len,
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__wsum sum, int *err)
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{
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if (!access_ok (VERIFY_WRITE, dst, len)) {
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*err = -EFAULT;
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return sum;
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} else {
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register unsigned long ret asm("o0") = (unsigned long)src;
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register char __user *d asm("o1") = dst;
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register int l asm("g1") = len;
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register __wsum s asm("g7") = sum;
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__asm__ __volatile__ (
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".section __ex_table,#alloc\n\t"
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".align 4\n\t"
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".word 1f,1\n\t"
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".previous\n"
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"1:\n\t"
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"call __csum_partial_copy_sparc_generic\n\t"
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" st %8, [%%sp + 64]\n"
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: "=&r" (ret), "=&r" (d), "=&r" (l), "=&r" (s)
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: "0" (ret), "1" (d), "2" (l), "3" (s), "r" (err)
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: "o2", "o3", "o4", "o5", "o7",
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"g2", "g3", "g4", "g5",
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"cc", "memory");
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return (__force __wsum)ret;
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}
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}
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#define HAVE_CSUM_COPY_USER
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#define csum_and_copy_to_user csum_partial_copy_to_user
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/* ihl is always 5 or greater, almost always is 5, and iph is word aligned
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* the majority of the time.
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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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__sum16 sum;
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/* Note: We must read %2 before we touch %0 for the first time,
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* because GCC can legitimately use the same register for
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* both operands.
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*/
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__asm__ __volatile__("sub\t%2, 4, %%g4\n\t"
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"ld\t[%1 + 0x00], %0\n\t"
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"ld\t[%1 + 0x04], %%g2\n\t"
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"ld\t[%1 + 0x08], %%g3\n\t"
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"addcc\t%%g2, %0, %0\n\t"
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"addxcc\t%%g3, %0, %0\n\t"
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"ld\t[%1 + 0x0c], %%g2\n\t"
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"ld\t[%1 + 0x10], %%g3\n\t"
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"addxcc\t%%g2, %0, %0\n\t"
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"addx\t%0, %%g0, %0\n"
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"1:\taddcc\t%%g3, %0, %0\n\t"
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"add\t%1, 4, %1\n\t"
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"addxcc\t%0, %%g0, %0\n\t"
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"subcc\t%%g4, 1, %%g4\n\t"
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"be,a\t2f\n\t"
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"sll\t%0, 16, %%g2\n\t"
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"b\t1b\n\t"
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"ld\t[%1 + 0x10], %%g3\n"
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"2:\taddcc\t%0, %%g2, %%g2\n\t"
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"srl\t%%g2, 16, %0\n\t"
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"addx\t%0, %%g0, %0\n\t"
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"xnor\t%%g0, %0, %0"
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: "=r" (sum), "=&r" (iph)
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: "r" (ihl), "1" (iph)
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: "g2", "g3", "g4", "cc", "memory");
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return sum;
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}
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/* Fold a partial checksum without adding pseudo headers. */
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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__ __volatile__("addcc\t%0, %1, %1\n\t"
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"srl\t%1, 16, %1\n\t"
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"addx\t%1, %%g0, %1\n\t"
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"xnor\t%%g0, %1, %0"
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: "=&r" (sum), "=r" (tmp)
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: "0" (sum), "1" ((__force u32)sum<<16)
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: "cc");
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return (__force __sum16)sum;
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}
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static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
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unsigned short len,
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unsigned short proto,
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__wsum sum)
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{
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__asm__ __volatile__("addcc\t%1, %0, %0\n\t"
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"addxcc\t%2, %0, %0\n\t"
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"addxcc\t%3, %0, %0\n\t"
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"addx\t%0, %%g0, %0\n\t"
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: "=r" (sum), "=r" (saddr)
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: "r" (daddr), "r" (proto + len), "0" (sum),
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"1" (saddr)
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: "cc");
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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 __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
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unsigned short len,
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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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#define _HAVE_ARCH_IPV6_CSUM
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static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
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const struct in6_addr *daddr,
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__u32 len, unsigned short proto,
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__wsum sum)
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{
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__asm__ __volatile__ (
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"addcc %3, %4, %%g4\n\t"
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"addxcc %5, %%g4, %%g4\n\t"
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"ld [%2 + 0x0c], %%g2\n\t"
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"ld [%2 + 0x08], %%g3\n\t"
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"addxcc %%g2, %%g4, %%g4\n\t"
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"ld [%2 + 0x04], %%g2\n\t"
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"addxcc %%g3, %%g4, %%g4\n\t"
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"ld [%2 + 0x00], %%g3\n\t"
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"addxcc %%g2, %%g4, %%g4\n\t"
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"ld [%1 + 0x0c], %%g2\n\t"
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"addxcc %%g3, %%g4, %%g4\n\t"
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"ld [%1 + 0x08], %%g3\n\t"
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"addxcc %%g2, %%g4, %%g4\n\t"
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"ld [%1 + 0x04], %%g2\n\t"
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"addxcc %%g3, %%g4, %%g4\n\t"
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"ld [%1 + 0x00], %%g3\n\t"
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"addxcc %%g2, %%g4, %%g4\n\t"
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"addxcc %%g3, %%g4, %0\n\t"
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"addx 0, %0, %0\n"
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: "=&r" (sum)
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: "r" (saddr), "r" (daddr),
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"r"(htonl(len)), "r"(htonl(proto)), "r"(sum)
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: "g2", "g3", "g4", "cc");
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return csum_fold(sum);
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}
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/* this routine is used for miscellaneous IP-like checksums, mainly in icmp.c */
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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 /* !(__SPARC_CHECKSUM_H) */
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