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 <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  */
  29 asmlinkage __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
  39 asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
  40                                             int len, __wsum 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 access_ok().
  48  */
  49 static inline
  50 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
  51                                         int len, __wsum sum)
  52 {
  53         return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
  54 }
  55
  56 static inline
  57 __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
  58                                    int len, __wsum sum, int *err_ptr)
  59 {
  60         return csum_partial_copy_generic((__force const void *)src, dst,
  61                                         len, sum, err_ptr, NULL);
  62 }
  63
  64 /*
  65  *      Fold a partial checksum
  66  */
  67
  68 static __inline__ __sum16 csum_fold(__wsum sum)
  69 {
  70         unsigned int __dummy;
  71         __asm__("extui  %1, %0, 16, 16\n\t"
  72                 "extui  %0 ,%0, 0, 16\n\t"
  73                 "add    %0, %0, %1\n\t"
  74                 "slli   %1, %0, 16\n\t"
  75                 "add    %0, %0, %1\n\t"
  76                 "extui  %0, %0, 16, 16\n\t"
  77                 "neg    %0, %0\n\t"
  78                 "addi   %0, %0, -1\n\t"
  79                 "extui  %0, %0, 0, 16\n\t"
  80                 : "=r" (sum), "=&r" (__dummy)
  81                 : "0" (sum));
  82         return (__force __sum16)sum;
  83 }
  84
  85 /*
  86  *      This is a version of ip_compute_csum() optimized for IP headers,
  87  *      which always checksum on 4 octet boundaries.
  88  */
  89 static __inline__ __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  90 {
  91         unsigned int sum, tmp, endaddr;
  92
  93         __asm__ __volatile__(
  94                 "sub            %0, %0, %0\n\t"
  95 #if XCHAL_HAVE_LOOPS
  96                 "loopgtz        %2, 2f\n\t"
  97 #else
  98                 "beqz           %2, 2f\n\t"
  99                 "slli           %4, %2, 2\n\t"
 100                 "add            %4, %4, %1\n\t"
 101                 "0:\t"
 102 #endif
 103                 "l32i           %3, %1, 0\n\t"
 104                 "add            %0, %0, %3\n\t"
 105                 "bgeu           %0, %3, 1f\n\t"
 106                 "addi           %0, %0, 1\n\t"
 107                 "1:\t"
 108                 "addi           %1, %1, 4\n\t"
 109 #if !XCHAL_HAVE_LOOPS
 110                 "blt            %1, %4, 0b\n\t"
 111 #endif
 112                 "2:\t"
 113         /* Since the input registers which are loaded with iph and ihl
 114            are modified, we must also specify them as outputs, or gcc
 115            will assume they contain their original values. */
 116                 : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (tmp),
 117                   "=&r" (endaddr)
 118                 : "1" (iph), "2" (ihl)
 119                 : "memory");
 120
 121         return  csum_fold(sum);
 122 }
 123
 124 static __inline__ __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 125                                                    unsigned short len,
 126                                                    unsigned short proto,
 127                                                    __wsum sum)
 128 {
 129
 130 #ifdef __XTENSA_EL__
 131         unsigned long len_proto = (len + proto) << 8;
 132 #elif defined(__XTENSA_EB__)
 133         unsigned long len_proto = len + proto;
 134 #else
 135 # error processor byte order undefined!
 136 #endif
 137         __asm__("add    %0, %0, %1\n\t"
 138                 "bgeu   %0, %1, 1f\n\t"
 139                 "addi   %0, %0, 1\n\t"
 140                 "1:\t"
 141                 "add    %0, %0, %2\n\t"
 142                 "bgeu   %0, %2, 1f\n\t"
 143                 "addi   %0, %0, 1\n\t"
 144                 "1:\t"
 145                 "add    %0, %0, %3\n\t"
 146                 "bgeu   %0, %3, 1f\n\t"
 147                 "addi   %0, %0, 1\n\t"
 148                 "1:\t"
 149                 : "=r" (sum), "=r" (len_proto)
 150                 : "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum));
 151         return sum;
 152 }
 153
 154 /*
 155  * computes the checksum of the TCP/UDP pseudo-header
 156  * returns a 16-bit checksum, already complemented
 157  */
 158 static __inline__ __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 159                                                        unsigned short len,
 160                                                        unsigned short proto,
 161                                                        __wsum sum)
 162 {
 163         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 164 }
 165
 166 /*
 167  * this routine is used for miscellaneous IP-like checksums, mainly
 168  * in icmp.c
 169  */
 170
 171 static __inline__ __sum16 ip_compute_csum(const void *buff, int len)
 172 {
 173         return csum_fold (csum_partial(buff, len, 0));
 174 }
 175
 176 #define _HAVE_ARCH_IPV6_CSUM
 177 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 178                                           const struct in6_addr *daddr,
 179                                           __u32 len, unsigned short proto,
 180                                           __wsum sum)
 181 {
 182         unsigned int __dummy;
 183         __asm__("l32i   %1, %2, 0\n\t"
 184                 "add    %0, %0, %1\n\t"
 185                 "bgeu   %0, %1, 1f\n\t"
 186                 "addi   %0, %0, 1\n\t"
 187                 "1:\t"
 188                 "l32i   %1, %2, 4\n\t"
 189                 "add    %0, %0, %1\n\t"
 190                 "bgeu   %0, %1, 1f\n\t"
 191                 "addi   %0, %0, 1\n\t"
 192                 "1:\t"
 193                 "l32i   %1, %2, 8\n\t"
 194                 "add    %0, %0, %1\n\t"
 195                 "bgeu   %0, %1, 1f\n\t"
 196                 "addi   %0, %0, 1\n\t"
 197                 "1:\t"
 198                 "l32i   %1, %2, 12\n\t"
 199                 "add    %0, %0, %1\n\t"
 200                 "bgeu   %0, %1, 1f\n\t"
 201                 "addi   %0, %0, 1\n\t"
 202                 "1:\t"
 203                 "l32i   %1, %3, 0\n\t"
 204                 "add    %0, %0, %1\n\t"
 205                 "bgeu   %0, %1, 1f\n\t"
 206                 "addi   %0, %0, 1\n\t"
 207                 "1:\t"
 208                 "l32i   %1, %3, 4\n\t"
 209                 "add    %0, %0, %1\n\t"
 210                 "bgeu   %0, %1, 1f\n\t"
 211                 "addi   %0, %0, 1\n\t"
 212                 "1:\t"
 213                 "l32i   %1, %3, 8\n\t"
 214                 "add    %0, %0, %1\n\t"
 215                 "bgeu   %0, %1, 1f\n\t"
 216                 "addi   %0, %0, 1\n\t"
 217                 "1:\t"
 218                 "l32i   %1, %3, 12\n\t"
 219                 "add    %0, %0, %1\n\t"
 220                 "bgeu   %0, %1, 1f\n\t"
 221                 "addi   %0, %0, 1\n\t"
 222                 "1:\t"
 223                 "add    %0, %0, %4\n\t"
 224                 "bgeu   %0, %4, 1f\n\t"
 225                 "addi   %0, %0, 1\n\t"
 226                 "1:\t"
 227                 "add    %0, %0, %5\n\t"
 228                 "bgeu   %0, %5, 1f\n\t"
 229                 "addi   %0, %0, 1\n\t"
 230                 "1:\t"
 231                 : "=r" (sum), "=&r" (__dummy)
 232                 : "r" (saddr), "r" (daddr),
 233                   "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
 234                 : "memory");
 235
 236         return csum_fold(sum);
 237 }
 238
 239 /*
 240  *      Copy and checksum to user
 241  */
 242 #define HAVE_CSUM_COPY_USER
 243 static __inline__ __wsum csum_and_copy_to_user(const void *src,
 244                                                void __user *dst, int len,
 245                                                __wsum sum, int *err_ptr)
 246 {
 247         if (access_ok(VERIFY_WRITE, dst, len))
 248                 return csum_partial_copy_generic(src,dst,len,sum,NULL,err_ptr);
 249
 250         if (len)
 251                 *err_ptr = -EFAULT;
 252
 253         return (__force __wsum)-1; /* invalid checksum */
 254 }
 255 #endif