LXR linux/arch/powerpc/include/asm/checksum.h

   1#ifndef _ASM_POWERPC_CHECKSUM_H
   2#define _ASM_POWERPC_CHECKSUM_H
   3#ifdef __KERNEL__
   4
   5/*
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the License, or (at your option) any later version.
  10 */
  11
  12/*
  13 * This is a version of ip_compute_csum() optimized for IP headers,
  14 * which always checksum on 4 octet boundaries.  ihl is the number
  15 * of 32-bit words and is always >= 5.
  16 */
  17#ifdef CONFIG_GENERIC_CSUM
  18#include <asm-generic/checksum.h>
  19#else
  20extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
  21
  22/*
  23 * computes the checksum of a memory block at buff, length len,
  24 * and adds in "sum" (32-bit)
  25 *
  26 * returns a 32-bit number suitable for feeding into itself
  27 * or csum_tcpudp_magic
  28 *
  29 * this function must be called with even lengths, except
  30 * for the last fragment, which may be odd
  31 *
  32 * it's best to have buff aligned on a 32-bit boundary
  33 */
  34extern __wsum csum_partial(const void *buff, int len, __wsum sum);
  35
  36/*
  37 * Computes the checksum of a memory block at src, length len,
  38 * and adds in "sum" (32-bit), while copying the block to dst.
  39 * If an access exception occurs on src or dst, it stores -EFAULT
  40 * to *src_err or *dst_err respectively (if that pointer is not
  41 * NULL), and, for an error on src, zeroes the rest of dst.
  42 *
  43 * Like csum_partial, this must be called with even lengths,
  44 * except for the last fragment.
  45 */
  46extern __wsum csum_partial_copy_generic(const void *src, void *dst,
  47                                              int len, __wsum sum,
  48                                              int *src_err, int *dst_err);
  49
  50#ifdef __powerpc64__
  51#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
  52extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
  53                                      int len, __wsum sum, int *err_ptr);
  54#define HAVE_CSUM_COPY_USER
  55extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
  56                                    int len, __wsum sum, int *err_ptr);
  57#else
  58/*
  59 * the same as csum_partial, but copies from src to dst while it
  60 * checksums.
  61 */
  62#define csum_partial_copy_from_user(src, dst, len, sum, errp)   \
  63        csum_partial_copy_generic((__force const void *)(src), (dst), (len), (sum), (errp), NULL)
  64#endif
  65
  66#define csum_partial_copy_nocheck(src, dst, len, sum)   \
  67        csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
  68
  69
  70/*
  71 * turns a 32-bit partial checksum (e.g. from csum_partial) into a
  72 * 1's complement 16-bit checksum.
  73 */
  74static inline __sum16 csum_fold(__wsum sum)
  75{
  76        unsigned int tmp;
  77
  78        /* swap the two 16-bit halves of sum */
  79        __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
  80        /* if there is a carry from adding the two 16-bit halves,
  81           it will carry from the lower half into the upper half,
  82           giving us the correct sum in the upper half. */
  83        return (__force __sum16)(~((__force u32)sum + tmp) >> 16);
  84}
  85
  86/*
  87 * this routine is used for miscellaneous IP-like checksums, mainly
  88 * in icmp.c
  89 */
  90static inline __sum16 ip_compute_csum(const void *buff, int len)
  91{
  92        return csum_fold(csum_partial(buff, len, 0));
  93}
  94
  95static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
  96                                     unsigned short len,
  97                                     unsigned short proto,
  98                                     __wsum sum)
  99{
 100#ifdef __powerpc64__
 101        unsigned long s = (__force u32)sum;
 102
 103        s += (__force u32)saddr;
 104        s += (__force u32)daddr;
 105        s += proto + len;
 106        s += (s >> 32);
 107        return (__force __wsum) s;
 108#else
 109    __asm__("\n\
 110        addc %0,%0,%1 \n\
 111        adde %0,%0,%2 \n\
 112        adde %0,%0,%3 \n\
 113        addze %0,%0 \n\
 114        "
 115        : "=r" (sum)
 116        : "r" (daddr), "r"(saddr), "r"(proto + len), "0"(sum));
 117        return sum;
 118#endif
 119}
 120
 121/*
 122 * computes the checksum of the TCP/UDP pseudo-header
 123 * returns a 16-bit checksum, already complemented
 124 */
 125static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 126                                        unsigned short len,
 127                                        unsigned short proto,
 128                                        __wsum sum)
 129{
 130        return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
 131}
 132
 133#define HAVE_ARCH_CSUM_ADD
 134static inline __wsum csum_add(__wsum csum, __wsum addend)
 135{
 136#ifdef __powerpc64__
 137        u64 res = (__force u64)csum;
 138
 139        res += (__force u64)addend;
 140        return (__force __wsum)((u32)res + (res >> 32));
 141#else
 142        asm("addc %0,%0,%1;"
 143            "addze %0,%0;"
 144            : "+r" (csum) : "r" (addend));
 145        return csum;
 146#endif
 147}
 148
 149#endif
 150#endif /* __KERNEL__ */
 151#endif
 152