arch/xtensa/include/asm/checksum.h

   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 <linux/uaccess.h>
  16 #include <asm/core.h>
  17
  18 /*
  19  * computes the checksum of a memory block at buff, length len,
  20  * and adds in "sum" (32-bit)
  21  *
  22  * returns a 32-bit number suitable for feeding into itself
  23  * or csum_tcpudp_magic
  24  *
  25  * this function must be called with even lengths, except
  26  * for the last fragment, which may be odd
  27  *
  28  * it's best to have buff aligned on a 32-bit boundary
  29  */
  30 asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
  31
  32 /*
  33  * the same as csum_partial, but copies from src while it
  34  * checksums, and handles user-space pointer exceptions correctly, when needed.
  35  *
  36  * here even more important to align src and dst on a 32-bit (or even
  37  * better 64-bit) boundary
  38  */
  39
  40 asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
  41
  42 #define _HAVE_ARCH_CSUM_AND_COPY
  43 /*
  44  *      Note: when you get a NULL pointer exception here this means someone
  45  *      passed in an incorrect kernel address to one of these functions.
  46  */
  47 static inline
  48 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
  49 {
  50         return csum_partial_copy_generic(src, dst, len);
  51 }
  52
  53 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
  54 static inline
  55 __wsum csum_and_copy_from_user(const void __user *src, void *dst,
  56                                    int len)
  57 {
  58         if (!access_ok(src, len))
  59                 return 0;
  60         return csum_partial_copy_generic((__force const void *)src, dst, len);
  61 }
  62
  63 /*
  64  *      Fold a partial checksum
  65  */
  66
  67 static __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  */
  88 static __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),
 116                   "=&r" (endaddr)
 117                 : "1" (iph), "2" (ihl)
 118                 : "memory");
 119
 120         return  csum_fold(sum);
 121 }
 122
 123 static __inline__ __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 124                                             __u32 len, __u8 proto,
 125                                             __wsum sum)
 126 {
 127
 128 #ifdef __XTENSA_EL__
 129         unsigned long len_proto = (len + proto) << 8;
 130 #elif defined(__XTENSA_EB__)
 131         unsigned long len_proto = len + proto;
 132 #else
 133 # error processor byte order undefined!
 134 #endif
 135         __asm__("add    %0, %0, %1\n\t"
 136                 "bgeu   %0, %1, 1f\n\t"
 137                 "addi   %0, %0, 1\n\t"
 138                 "1:\t"
 139                 "add    %0, %0, %2\n\t"
 140                 "bgeu   %0, %2, 1f\n\t"
 141                 "addi   %0, %0, 1\n\t"
 142                 "1:\t"
 143                 "add    %0, %0, %3\n\t"
 144                 "bgeu   %0, %3, 1f\n\t"
 145                 "addi   %0, %0, 1\n\t"
 146                 "1:\t"
 147                 : "=r" (sum), "=r" (len_proto)
 148                 : "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum));
 149         return sum;
 150 }
 151
 152 /*
 153  * computes the checksum of the TCP/UDP pseudo-header
 154  * returns a 16-bit checksum, already complemented
 155  */
 156 static __inline__ __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 157                                             __u32 len, __u8 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
 168 static __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
 174 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 175                                           const struct in6_addr *daddr,
 176                                           __u32 len, __u8 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                 : "memory");
 232
 233         return csum_fold(sum);
 234 }
 235
 236 /*
 237  *      Copy and checksum to user
 238  */
 239 #define HAVE_CSUM_COPY_USER
 240 static __inline__ __wsum csum_and_copy_to_user(const void *src,
 241                                                void __user *dst, int len)
 242 {
 243         if (!access_ok(dst, len))
 244                 return 0;
 245         return csum_partial_copy_generic(src, (__force void *)dst, len);
 246 }
 247 #endif