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/config.h>
  15 #include <linux/in6.h>
  16 #include <xtensa/config/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 unsigned int csum_partial(const unsigned char * buff, int len, unsigned int 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 unsigned int csum_partial_copy_generic( const char *src, char *dst, int len, int sum,
  41                                                    int *src_err_ptr, int *dst_err_ptr);
  42
  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  *      If you use these functions directly please don't forget the
  48  *      verify_area().
  49  */
  50 static inline
  51 unsigned int csum_partial_copy_nocheck ( const char *src, char *dst,
  52                                         int len, int sum)
  53 {
  54         return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);
  55 }
  56
  57 static inline
  58 unsigned int csum_partial_copy_from_user ( const char *src, char *dst,
  59                                                 int len, int sum, int *err_ptr)
  60 {
  61         return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, NULL);
  62 }
  63
  64 /*
  65  * These are the old (and unsafe) way of doing checksums, a warning message will be
  66  * printed if they are used and an exeption occurs.
  67  *
  68  * these functions should go away after some time.
  69  */
  70
  71 #define csum_partial_copy_fromuser csum_partial_copy
  72 unsigned int csum_partial_copy( const char *src, char *dst, int len, int sum);
  73
  74 /*
  75  *      Fold a partial checksum
  76  */
  77
  78 static __inline__ unsigned int csum_fold(unsigned int sum)
  79 {
  80         unsigned int __dummy;
  81         __asm__("extui  %1, %0, 16, 16\n\t"
  82                 "extui  %0 ,%0, 0, 16\n\t"
  83                 "add    %0, %0, %1\n\t"
  84                 "slli   %1, %0, 16\n\t"
  85                 "add    %0, %0, %1\n\t"
  86                 "extui  %0, %0, 16, 16\n\t"
  87                 "neg    %0, %0\n\t"
  88                 "addi   %0, %0, -1\n\t"
  89                 "extui  %0, %0, 0, 16\n\t"
  90                 : "=r" (sum), "=&r" (__dummy)
  91                 : "0" (sum));
  92         return sum;
  93 }
  94
  95 /*
  96  *      This is a version of ip_compute_csum() optimized for IP headers,
  97  *      which always checksum on 4 octet boundaries.
  98  */
  99 static __inline__ unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl)
 100 {
 101         unsigned int sum, tmp, endaddr;
 102
 103         __asm__ __volatile__(
 104                 "sub            %0, %0, %0\n\t"
 105 #if XCHAL_HAVE_LOOPS
 106                 "loopgtz        %2, 2f\n\t"
 107 #else
 108                 "beqz           %2, 2f\n\t"
 109                 "slli           %4, %2, 2\n\t"
 110                 "add            %4, %4, %1\n\t"
 111                 "0:\t"
 112 #endif
 113                 "l32i           %3, %1, 0\n\t"
 114                 "add            %0, %0, %3\n\t"
 115                 "bgeu           %0, %3, 1f\n\t"
 116                 "addi           %0, %0, 1\n\t"
 117                 "1:\t"
 118                 "addi           %1, %1, 4\n\t"
 119 #if !XCHAL_HAVE_LOOPS
 120                 "blt            %1, %4, 0b\n\t"
 121 #endif
 122                 "2:\t"
 123         /* Since the input registers which are loaded with iph and ihl
 124            are modified, we must also specify them as outputs, or gcc
 125            will assume they contain their original values. */
 126                 : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (tmp), "=&r" (endaddr)
 127                 : "1" (iph), "2" (ihl));
 128
 129         return  csum_fold(sum);
 130 }
 131
 132 static __inline__ unsigned long csum_tcpudp_nofold(unsigned long saddr,
 133                                                    unsigned long daddr,
 134                                                    unsigned short len,
 135                                                    unsigned short proto,
 136                                                    unsigned int sum)
 137 {
 138
 139 #ifdef __XTENSA_EL__
 140         unsigned long len_proto = (ntohs(len)<<16)+proto*256;
 141 #elif defined(__XTENSA_EB__)
 142         unsigned long len_proto = (proto<<16)+len;
 143 #else
 144 # error processor byte order undefined!
 145 #endif
 146         __asm__("add    %0, %0, %1\n\t"
 147                 "bgeu   %0, %1, 1f\n\t"
 148                 "addi   %0, %0, 1\n\t"
 149                 "1:\t"
 150                 "add    %0, %0, %2\n\t"
 151                 "bgeu   %0, %2, 1f\n\t"
 152                 "addi   %0, %0, 1\n\t"
 153                 "1:\t"
 154                 "add    %0, %0, %3\n\t"
 155                 "bgeu   %0, %3, 1f\n\t"
 156                 "addi   %0, %0, 1\n\t"
 157                 "1:\t"
 158                 : "=r" (sum), "=r" (len_proto)
 159                 : "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum));
 160         return sum;
 161 }
 162
 163 /*
 164  * computes the checksum of the TCP/UDP pseudo-header
 165  * returns a 16-bit checksum, already complemented
 166  */
 167 static __inline__ unsigned short int csum_tcpudp_magic(unsigned long saddr,
 168                                                        unsigned long daddr,
 169                                                        unsigned short len,
 170                                                        unsigned short proto,
 171                                                        unsigned int sum)
 172 {
 173         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 174 }
 175
 176 /*
 177  * this routine is used for miscellaneous IP-like checksums, mainly
 178  * in icmp.c
 179  */
 180
 181 static __inline__ unsigned short ip_compute_csum(unsigned char * buff, int len)
 182 {
 183     return csum_fold (csum_partial(buff, len, 0));
 184 }
 185
 186 #define _HAVE_ARCH_IPV6_CSUM
 187 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
 188                                                      struct in6_addr *daddr,
 189                                                      __u32 len,
 190                                                      unsigned short proto,
 191                                                      unsigned int sum)
 192 {
 193         unsigned int __dummy;
 194         __asm__("l32i   %1, %2, 0\n\t"
 195                 "add    %0, %0, %1\n\t"
 196                 "bgeu   %0, %1, 1f\n\t"
 197                 "addi   %0, %0, 1\n\t"
 198                 "1:\t"
 199                 "l32i   %1, %2, 4\n\t"
 200                 "add    %0, %0, %1\n\t"
 201                 "bgeu   %0, %1, 1f\n\t"
 202                 "addi   %0, %0, 1\n\t"
 203                 "1:\t"
 204                 "l32i   %1, %2, 8\n\t"
 205                 "add    %0, %0, %1\n\t"
 206                 "bgeu   %0, %1, 1f\n\t"
 207                 "addi   %0, %0, 1\n\t"
 208                 "1:\t"
 209                 "l32i   %1, %2, 12\n\t"
 210                 "add    %0, %0, %1\n\t"
 211                 "bgeu   %0, %1, 1f\n\t"
 212                 "addi   %0, %0, 1\n\t"
 213                 "1:\t"
 214                 "l32i   %1, %3, 0\n\t"
 215                 "add    %0, %0, %1\n\t"
 216                 "bgeu   %0, %1, 1f\n\t"
 217                 "addi   %0, %0, 1\n\t"
 218                 "1:\t"
 219                 "l32i   %1, %3, 4\n\t"
 220                 "add    %0, %0, %1\n\t"
 221                 "bgeu   %0, %1, 1f\n\t"
 222                 "addi   %0, %0, 1\n\t"
 223                 "1:\t"
 224                 "l32i   %1, %3, 8\n\t"
 225                 "add    %0, %0, %1\n\t"
 226                 "bgeu   %0, %1, 1f\n\t"
 227                 "addi   %0, %0, 1\n\t"
 228                 "1:\t"
 229                 "l32i   %1, %3, 12\n\t"
 230                 "add    %0, %0, %1\n\t"
 231                 "bgeu   %0, %1, 1f\n\t"
 232                 "addi   %0, %0, 1\n\t"
 233                 "1:\t"
 234                 "add    %0, %0, %4\n\t"
 235                 "bgeu   %0, %4, 1f\n\t"
 236                 "addi   %0, %0, 1\n\t"
 237                 "1:\t"
 238                 "add    %0, %0, %5\n\t"
 239                 "bgeu   %0, %5, 1f\n\t"
 240                 "addi   %0, %0, 1\n\t"
 241                 "1:\t"
 242                 : "=r" (sum), "=&r" (__dummy)
 243                 : "r" (saddr), "r" (daddr),
 244                   "r" (htonl(len)), "r" (htonl(proto)), "0" (sum));
 245
 246         return csum_fold(sum);
 247 }
 248
 249 /*
 250  *      Copy and checksum to user
 251  */
 252 #define HAVE_CSUM_COPY_USER
 253 static __inline__ unsigned int csum_and_copy_to_user (const char *src, char *dst,
 254                                     int len, int sum, int *err_ptr)
 255 {
 256         if (access_ok(VERIFY_WRITE, dst, len))
 257                 return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);
 258
 259         if (len)
 260                 *err_ptr = -EFAULT;
 261
 262         return -1; /* invalid checksum */
 263 }
 264 #endif