linux/include/asm-xtensa/checksum.h
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   1/*
   2 * include/asm-xtensa/checksum.h
   3 *
   4 * This file is subject to the terms and conditions of the GNU General Public
   5 * License.  See the file "COPYING" in the main directory of this archive
   6 * for more details.
   7 *
   8 * Copyright (C) 2001 - 2005 Tensilica Inc.
   9 */
  10
  11#ifndef _XTENSA_CHECKSUM_H
  12#define _XTENSA_CHECKSUM_H
  13
  14#include <linux/in6.h>
  15#include <asm/variant/core.h>
  16
  17/*
  18 * computes the checksum of a memory block at buff, length len,
  19 * and adds in "sum" (32-bit)
  20 *
  21 * returns a 32-bit number suitable for feeding into itself
  22 * or csum_tcpudp_magic
  23 *
  24 * this function must be called with even lengths, except
  25 * for the last fragment, which may be odd
  26 *
  27 * it's best to have buff aligned on a 32-bit boundary
  28 */
  29asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
  30
  31/*
  32 * the same as csum_partial, but copies from src while it
  33 * checksums, and handles user-space pointer exceptions correctly, when needed.
  34 *
  35 * here even more important to align src and dst on a 32-bit (or even
  36 * better 64-bit) boundary
  37 */
  38
  39asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len, __wsum sum,
  40                                                   int *src_err_ptr, int *dst_err_ptr);
  41
  42/*
  43 *      Note: when you get a NULL pointer exception here this means someone
  44 *      passed in an incorrect kernel address to one of these functions.
  45 *
  46 *      If you use these functions directly please don't forget the access_ok().
  47 */
  48static inline
  49__wsum csum_partial_copy_nocheck(const void *src, void *dst,
  50                                        int len, __wsum sum)
  51{
  52        return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
  53}
  54
  55static inline
  56__wsum csum_partial_copy_from_user(const void __user *src, void *dst,
  57                                                int len, __wsum sum, int *err_ptr)
  58{
  59        return csum_partial_copy_generic((__force const void *)src, dst,
  60                                        len, sum, err_ptr, NULL);
  61}
  62
  63/*
  64 *      Fold a partial checksum
  65 */
  66
  67static __inline__ __sum16 csum_fold(__wsum sum)
  68{
  69        unsigned int __dummy;
  70        __asm__("extui  %1, %0, 16, 16\n\t"
  71                "extui  %0 ,%0, 0, 16\n\t"
  72                "add    %0, %0, %1\n\t"
  73                "slli   %1, %0, 16\n\t"
  74                "add    %0, %0, %1\n\t"
  75                "extui  %0, %0, 16, 16\n\t"
  76                "neg    %0, %0\n\t"
  77                "addi   %0, %0, -1\n\t"
  78                "extui  %0, %0, 0, 16\n\t"
  79                : "=r" (sum), "=&r" (__dummy)
  80                : "0" (sum));
  81        return (__force __sum16)sum;
  82}
  83
  84/*
  85 *      This is a version of ip_compute_csum() optimized for IP headers,
  86 *      which always checksum on 4 octet boundaries.
  87 */
  88static __inline__ __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  89{
  90        unsigned int sum, tmp, endaddr;
  91
  92        __asm__ __volatile__(
  93                "sub            %0, %0, %0\n\t"
  94#if XCHAL_HAVE_LOOPS
  95                "loopgtz        %2, 2f\n\t"
  96#else
  97                "beqz           %2, 2f\n\t"
  98                "slli           %4, %2, 2\n\t"
  99                "add            %4, %4, %1\n\t"
 100                "0:\t"
 101#endif
 102                "l32i           %3, %1, 0\n\t"
 103                "add            %0, %0, %3\n\t"
 104                "bgeu           %0, %3, 1f\n\t"
 105                "addi           %0, %0, 1\n\t"
 106                "1:\t"
 107                "addi           %1, %1, 4\n\t"
 108#if !XCHAL_HAVE_LOOPS
 109                "blt            %1, %4, 0b\n\t"
 110#endif
 111                "2:\t"
 112        /* Since the input registers which are loaded with iph and ihl
 113           are modified, we must also specify them as outputs, or gcc
 114           will assume they contain their original values. */
 115                : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (tmp), "=&r" (endaddr)
 116                : "1" (iph), "2" (ihl));
 117
 118        return  csum_fold(sum);
 119}
 120
 121static __inline__ __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 122                                                   unsigned short len,
 123                                                   unsigned short proto,
 124                                                   __wsum sum)
 125{
 126
 127#ifdef __XTENSA_EL__
 128        unsigned long len_proto = (len + proto) << 8;
 129#elif defined(__XTENSA_EB__)
 130        unsigned long len_proto = len + proto;
 131#else
 132# error processor byte order undefined!
 133#endif
 134        __asm__("add    %0, %0, %1\n\t"
 135                "bgeu   %0, %1, 1f\n\t"
 136                "addi   %0, %0, 1\n\t"
 137                "1:\t"
 138                "add    %0, %0, %2\n\t"
 139                "bgeu   %0, %2, 1f\n\t"
 140                "addi   %0, %0, 1\n\t"
 141                "1:\t"
 142                "add    %0, %0, %3\n\t"
 143                "bgeu   %0, %3, 1f\n\t"
 144                "addi   %0, %0, 1\n\t"
 145                "1:\t"
 146                : "=r" (sum), "=r" (len_proto)
 147                : "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum));
 148        return sum;
 149}
 150
 151/*
 152 * computes the checksum of the TCP/UDP pseudo-header
 153 * returns a 16-bit checksum, already complemented
 154 */
 155static __inline__ __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 156                                                       unsigned short len,
 157                                                       unsigned short proto,
 158                                                       __wsum sum)
 159{
 160        return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 161}
 162
 163/*
 164 * this routine is used for miscellaneous IP-like checksums, mainly
 165 * in icmp.c
 166 */
 167
 168static __inline__ __sum16 ip_compute_csum(const void *buff, int len)
 169{
 170    return csum_fold (csum_partial(buff, len, 0));
 171}
 172
 173#define _HAVE_ARCH_IPV6_CSUM
 174static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 175                                          const struct in6_addr *daddr,
 176                                          __u32 len, unsigned short proto,
 177                                          __wsum sum)
 178{
 179        unsigned int __dummy;
 180        __asm__("l32i   %1, %2, 0\n\t"
 181                "add    %0, %0, %1\n\t"
 182                "bgeu   %0, %1, 1f\n\t"
 183                "addi   %0, %0, 1\n\t"
 184                "1:\t"
 185                "l32i   %1, %2, 4\n\t"
 186                "add    %0, %0, %1\n\t"
 187                "bgeu   %0, %1, 1f\n\t"
 188                "addi   %0, %0, 1\n\t"
 189                "1:\t"
 190                "l32i   %1, %2, 8\n\t"
 191                "add    %0, %0, %1\n\t"
 192                "bgeu   %0, %1, 1f\n\t"
 193                "addi   %0, %0, 1\n\t"
 194                "1:\t"
 195                "l32i   %1, %2, 12\n\t"
 196                "add    %0, %0, %1\n\t"
 197                "bgeu   %0, %1, 1f\n\t"
 198                "addi   %0, %0, 1\n\t"
 199                "1:\t"
 200                "l32i   %1, %3, 0\n\t"
 201                "add    %0, %0, %1\n\t"
 202                "bgeu   %0, %1, 1f\n\t"
 203                "addi   %0, %0, 1\n\t"
 204                "1:\t"
 205                "l32i   %1, %3, 4\n\t"
 206                "add    %0, %0, %1\n\t"
 207                "bgeu   %0, %1, 1f\n\t"
 208                "addi   %0, %0, 1\n\t"
 209                "1:\t"
 210                "l32i   %1, %3, 8\n\t"
 211                "add    %0, %0, %1\n\t"
 212                "bgeu   %0, %1, 1f\n\t"
 213                "addi   %0, %0, 1\n\t"
 214                "1:\t"
 215                "l32i   %1, %3, 12\n\t"
 216                "add    %0, %0, %1\n\t"
 217                "bgeu   %0, %1, 1f\n\t"
 218                "addi   %0, %0, 1\n\t"
 219                "1:\t"
 220                "add    %0, %0, %4\n\t"
 221                "bgeu   %0, %4, 1f\n\t"
 222                "addi   %0, %0, 1\n\t"
 223                "1:\t"
 224                "add    %0, %0, %5\n\t"
 225                "bgeu   %0, %5, 1f\n\t"
 226                "addi   %0, %0, 1\n\t"
 227                "1:\t"
 228                : "=r" (sum), "=&r" (__dummy)
 229                : "r" (saddr), "r" (daddr),
 230                  "r" (htonl(len)), "r" (htonl(proto)), "0" (sum));
 231
 232        return csum_fold(sum);
 233}
 234
 235/*
 236 *      Copy and checksum to user
 237 */
 238#define HAVE_CSUM_COPY_USER
 239static __inline__ __wsum csum_and_copy_to_user(const void *src, void __user *dst,
 240                                    int len, __wsum sum, int *err_ptr)
 241{
 242        if (access_ok(VERIFY_WRITE, dst, len))
 243                return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);
 244
 245        if (len)
 246                *err_ptr = -EFAULT;
 247
 248        return (__force __wsum)-1; /* invalid checksum */
 249}
 250#endif
 251