include/asm-xtensa/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 <xtensa/config/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  */
  29 asmlinkage unsigned int csum_partial(const unsigned char * buff, int len, unsigned int 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
  39 asmlinkage unsigned int csum_partial_copy_generic( const char *src, char *dst, int len, int 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  */
  48 static inline
  49 unsigned int csum_partial_copy_nocheck ( const char *src, char *dst,
  50                                         int len, int sum)
  51 {
  52         return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);
  53 }
  54
  55 static inline
  56 unsigned int csum_partial_copy_from_user ( const char *src, char *dst,
  57                                                 int len, int sum, int *err_ptr)
  58 {
  59         return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, NULL);
  60 }
  61
  62 /*
  63  * These are the old (and unsafe) way of doing checksums, a warning message will be
  64  * printed if they are used and an exeption occurs.
  65  *
  66  * these functions should go away after some time.
  67  */
  68
  69 #define csum_partial_copy_fromuser csum_partial_copy
  70 unsigned int csum_partial_copy( const char *src, char *dst, int len, int sum);
  71
  72 /*
  73  *      Fold a partial checksum
  74  */
  75
  76 static __inline__ unsigned int csum_fold(unsigned int sum)
  77 {
  78         unsigned int __dummy;
  79         __asm__("extui  %1, %0, 16, 16\n\t"
  80                 "extui  %0 ,%0, 0, 16\n\t"
  81                 "add    %0, %0, %1\n\t"
  82                 "slli   %1, %0, 16\n\t"
  83                 "add    %0, %0, %1\n\t"
  84                 "extui  %0, %0, 16, 16\n\t"
  85                 "neg    %0, %0\n\t"
  86                 "addi   %0, %0, -1\n\t"
  87                 "extui  %0, %0, 0, 16\n\t"
  88                 : "=r" (sum), "=&r" (__dummy)
  89                 : "0" (sum));
  90         return sum;
  91 }
  92
  93 /*
  94  *      This is a version of ip_compute_csum() optimized for IP headers,
  95  *      which always checksum on 4 octet boundaries.
  96  */
  97 static __inline__ unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl)
  98 {
  99         unsigned int sum, tmp, endaddr;
 100
 101         __asm__ __volatile__(
 102                 "sub            %0, %0, %0\n\t"
 103 #if XCHAL_HAVE_LOOPS
 104                 "loopgtz        %2, 2f\n\t"
 105 #else
 106                 "beqz           %2, 2f\n\t"
 107                 "slli           %4, %2, 2\n\t"
 108                 "add            %4, %4, %1\n\t"
 109                 "0:\t"
 110 #endif
 111                 "l32i           %3, %1, 0\n\t"
 112                 "add            %0, %0, %3\n\t"
 113                 "bgeu           %0, %3, 1f\n\t"
 114                 "addi           %0, %0, 1\n\t"
 115                 "1:\t"
 116                 "addi           %1, %1, 4\n\t"
 117 #if !XCHAL_HAVE_LOOPS
 118                 "blt            %1, %4, 0b\n\t"
 119 #endif
 120                 "2:\t"
 121         /* Since the input registers which are loaded with iph and ihl
 122            are modified, we must also specify them as outputs, or gcc
 123            will assume they contain their original values. */
 124                 : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (tmp), "=&r" (endaddr)
 125                 : "1" (iph), "2" (ihl));
 126
 127         return  csum_fold(sum);
 128 }
 129
 130 static __inline__ unsigned long csum_tcpudp_nofold(unsigned long saddr,
 131                                                    unsigned long daddr,
 132                                                    unsigned short len,
 133                                                    unsigned short proto,
 134                                                    unsigned int sum)
 135 {
 136
 137 #ifdef __XTENSA_EL__
 138         unsigned long len_proto = (ntohs(len)<<16)+proto*256;
 139 #elif defined(__XTENSA_EB__)
 140         unsigned long len_proto = (proto<<16)+len;
 141 #else
 142 # error processor byte order undefined!
 143 #endif
 144         __asm__("add    %0, %0, %1\n\t"
 145                 "bgeu   %0, %1, 1f\n\t"
 146                 "addi   %0, %0, 1\n\t"
 147                 "1:\t"
 148                 "add    %0, %0, %2\n\t"
 149                 "bgeu   %0, %2, 1f\n\t"
 150                 "addi   %0, %0, 1\n\t"
 151                 "1:\t"
 152                 "add    %0, %0, %3\n\t"
 153                 "bgeu   %0, %3, 1f\n\t"
 154                 "addi   %0, %0, 1\n\t"
 155                 "1:\t"
 156                 : "=r" (sum), "=r" (len_proto)
 157                 : "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum));
 158         return sum;
 159 }
 160
 161 /*
 162  * computes the checksum of the TCP/UDP pseudo-header
 163  * returns a 16-bit checksum, already complemented
 164  */
 165 static __inline__ unsigned short int csum_tcpudp_magic(unsigned long saddr,
 166                                                        unsigned long daddr,
 167                                                        unsigned short len,
 168                                                        unsigned short proto,
 169                                                        unsigned int sum)
 170 {
 171         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 172 }
 173
 174 /*
 175  * this routine is used for miscellaneous IP-like checksums, mainly
 176  * in icmp.c
 177  */
 178
 179 static __inline__ unsigned short ip_compute_csum(unsigned char * buff, int len)
 180 {
 181     return csum_fold (csum_partial(buff, len, 0));
 182 }
 183
 184 #define _HAVE_ARCH_IPV6_CSUM
 185 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
 186                                                      struct in6_addr *daddr,
 187                                                      __u32 len,
 188                                                      unsigned short proto,
 189                                                      unsigned int sum)
 190 {
 191         unsigned int __dummy;
 192         __asm__("l32i   %1, %2, 0\n\t"
 193                 "add    %0, %0, %1\n\t"
 194                 "bgeu   %0, %1, 1f\n\t"
 195                 "addi   %0, %0, 1\n\t"
 196                 "1:\t"
 197                 "l32i   %1, %2, 4\n\t"
 198                 "add    %0, %0, %1\n\t"
 199                 "bgeu   %0, %1, 1f\n\t"
 200                 "addi   %0, %0, 1\n\t"
 201                 "1:\t"
 202                 "l32i   %1, %2, 8\n\t"
 203                 "add    %0, %0, %1\n\t"
 204                 "bgeu   %0, %1, 1f\n\t"
 205                 "addi   %0, %0, 1\n\t"
 206                 "1:\t"
 207                 "l32i   %1, %2, 12\n\t"
 208                 "add    %0, %0, %1\n\t"
 209                 "bgeu   %0, %1, 1f\n\t"
 210                 "addi   %0, %0, 1\n\t"
 211                 "1:\t"
 212                 "l32i   %1, %3, 0\n\t"
 213                 "add    %0, %0, %1\n\t"
 214                 "bgeu   %0, %1, 1f\n\t"
 215                 "addi   %0, %0, 1\n\t"
 216                 "1:\t"
 217                 "l32i   %1, %3, 4\n\t"
 218                 "add    %0, %0, %1\n\t"
 219                 "bgeu   %0, %1, 1f\n\t"
 220                 "addi   %0, %0, 1\n\t"
 221                 "1:\t"
 222                 "l32i   %1, %3, 8\n\t"
 223                 "add    %0, %0, %1\n\t"
 224                 "bgeu   %0, %1, 1f\n\t"
 225                 "addi   %0, %0, 1\n\t"
 226                 "1:\t"
 227                 "l32i   %1, %3, 12\n\t"
 228                 "add    %0, %0, %1\n\t"
 229                 "bgeu   %0, %1, 1f\n\t"
 230                 "addi   %0, %0, 1\n\t"
 231                 "1:\t"
 232                 "add    %0, %0, %4\n\t"
 233                 "bgeu   %0, %4, 1f\n\t"
 234                 "addi   %0, %0, 1\n\t"
 235                 "1:\t"
 236                 "add    %0, %0, %5\n\t"
 237                 "bgeu   %0, %5, 1f\n\t"
 238                 "addi   %0, %0, 1\n\t"
 239                 "1:\t"
 240                 : "=r" (sum), "=&r" (__dummy)
 241                 : "r" (saddr), "r" (daddr),
 242                   "r" (htonl(len)), "r" (htonl(proto)), "0" (sum));
 243
 244         return csum_fold(sum);
 245 }
 246
 247 /*
 248  *      Copy and checksum to user
 249  */
 250 #define HAVE_CSUM_COPY_USER
 251 static __inline__ unsigned int csum_and_copy_to_user (const char *src, char *dst,
 252                                     int len, int sum, int *err_ptr)
 253 {
 254         if (access_ok(VERIFY_WRITE, dst, len))
 255                 return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);
 256
 257         if (len)
 258                 *err_ptr = -EFAULT;
 259
 260         return -1; /* invalid checksum */
 261 }
 262 #endif