include/asm-sh/checksum.h

   1 #ifndef __ASM_SH_CHECKSUM_H
   2 #define __ASM_SH_CHECKSUM_H
   3
   4 /*
   5  * This file is subject to the terms and conditions of the GNU General Public
   6  * License.  See the file "COPYING" in the main directory of this archive
   7  * for more details.
   8  *
   9  * Copyright (C) 1999 by Kaz Kojima & Niibe Yutaka
  10  */
  11
  12 #include <linux/in6.h>
  13
  14 /*
  15  * computes the checksum of a memory block at buff, length len,
  16  * and adds in "sum" (32-bit)
  17  *
  18  * returns a 32-bit number suitable for feeding into itself
  19  * or csum_tcpudp_magic
  20  *
  21  * this function must be called with even lengths, except
  22  * for the last fragment, which may be odd
  23  *
  24  * it's best to have buff aligned on a 32-bit boundary
  25  */
  26 asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
  27
  28 /*
  29  * the same as csum_partial, but copies from src while it
  30  * checksums, and handles user-space pointer exceptions correctly, when needed.
  31  *
  32  * here even more important to align src and dst on a 32-bit (or even
  33  * better 64-bit) boundary
  34  */
  35
  36 asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
  37                                             int len, __wsum sum,
  38                                             int *src_err_ptr, int *dst_err_ptr);
  39
  40 /*
  41  *      Note: when you get a NULL pointer exception here this means someone
  42  *      passed in an incorrect kernel address to one of these functions.
  43  *
  44  *      If you use these functions directly please don't forget the
  45  *      access_ok().
  46  */
  47 static inline
  48 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
  49                                  int len, __wsum sum)
  50 {
  51         return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
  52 }
  53
  54 static inline
  55 __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
  56                                    int len, __wsum sum, int *err_ptr)
  57 {
  58         return csum_partial_copy_generic((__force const void *)src, dst,
  59                                         len, sum, err_ptr, NULL);
  60 }
  61
  62 /*
  63  *      Fold a partial checksum
  64  */
  65
  66 static inline __sum16 csum_fold(__wsum sum)
  67 {
  68         unsigned int __dummy;
  69         __asm__("swap.w %0, %1\n\t"
  70                 "extu.w %0, %0\n\t"
  71                 "extu.w %1, %1\n\t"
  72                 "add    %1, %0\n\t"
  73                 "swap.w %0, %1\n\t"
  74                 "add    %1, %0\n\t"
  75                 "not    %0, %0\n\t"
  76                 : "=r" (sum), "=&r" (__dummy)
  77                 : "0" (sum)
  78                 : "t");
  79         return (__force __sum16)sum;
  80 }
  81
  82 /*
  83  *      This is a version of ip_compute_csum() optimized for IP headers,
  84  *      which always checksum on 4 octet boundaries.
  85  *
  86  *      i386 version by Jorge Cwik <jorge@laser.satlink.net>, adapted
  87  *      for linux by * Arnt Gulbrandsen.
  88  */
  89 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  90 {
  91         unsigned int sum, __dummy0, __dummy1;
  92
  93         __asm__ __volatile__(
  94                 "mov.l  @%1+, %0\n\t"
  95                 "mov.l  @%1+, %3\n\t"
  96                 "add    #-2, %2\n\t"
  97                 "clrt\n\t"
  98                 "1:\t"
  99                 "addc   %3, %0\n\t"
 100                 "movt   %4\n\t"
 101                 "mov.l  @%1+, %3\n\t"
 102                 "dt     %2\n\t"
 103                 "bf/s   1b\n\t"
 104                 " cmp/eq #1, %4\n\t"
 105                 "addc   %3, %0\n\t"
 106                 "addc   %2, %0"     /* Here %2 is 0, add carry-bit */
 107         /* Since the input registers which are loaded with iph and ihl
 108            are modified, we must also specify them as outputs, or gcc
 109            will assume they contain their original values. */
 110         : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (__dummy0), "=&z" (__dummy1)
 111         : "1" (iph), "2" (ihl)
 112         : "t");
 113
 114         return  csum_fold(sum);
 115 }
 116
 117 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 118                                         unsigned short len,
 119                                         unsigned short proto,
 120                                         __wsum sum)
 121 {
 122 #ifdef __LITTLE_ENDIAN__
 123         unsigned long len_proto = (proto + len) << 8;
 124 #else
 125         unsigned long len_proto = proto + len;
 126 #endif
 127         __asm__("clrt\n\t"
 128                 "addc   %0, %1\n\t"
 129                 "addc   %2, %1\n\t"
 130                 "addc   %3, %1\n\t"
 131                 "movt   %0\n\t"
 132                 "add    %1, %0"
 133                 : "=r" (sum), "=r" (len_proto)
 134                 : "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum)
 135                 : "t");
 136
 137         return sum;
 138 }
 139
 140 /*
 141  * computes the checksum of the TCP/UDP pseudo-header
 142  * returns a 16-bit checksum, already complemented
 143  */
 144 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 145                                         unsigned short len,
 146                                         unsigned short proto,
 147                                         __wsum sum)
 148 {
 149         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
 150 }
 151
 152 /*
 153  * this routine is used for miscellaneous IP-like checksums, mainly
 154  * in icmp.c
 155  */
 156 static inline __sum16 ip_compute_csum(const void *buff, int len)
 157 {
 158     return csum_fold(csum_partial(buff, len, 0));
 159 }
 160
 161 #define _HAVE_ARCH_IPV6_CSUM
 162 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 163                                       const struct in6_addr *daddr,
 164                                       __u32 len, unsigned short proto,
 165                                       __wsum sum)
 166 {
 167         unsigned int __dummy;
 168         __asm__("clrt\n\t"
 169                 "mov.l  @(0,%2), %1\n\t"
 170                 "addc   %1, %0\n\t"
 171                 "mov.l  @(4,%2), %1\n\t"
 172                 "addc   %1, %0\n\t"
 173                 "mov.l  @(8,%2), %1\n\t"
 174                 "addc   %1, %0\n\t"
 175                 "mov.l  @(12,%2), %1\n\t"
 176                 "addc   %1, %0\n\t"
 177                 "mov.l  @(0,%3), %1\n\t"
 178                 "addc   %1, %0\n\t"
 179                 "mov.l  @(4,%3), %1\n\t"
 180                 "addc   %1, %0\n\t"
 181                 "mov.l  @(8,%3), %1\n\t"
 182                 "addc   %1, %0\n\t"
 183                 "mov.l  @(12,%3), %1\n\t"
 184                 "addc   %1, %0\n\t"
 185                 "addc   %4, %0\n\t"
 186                 "addc   %5, %0\n\t"
 187                 "movt   %1\n\t"
 188                 "add    %1, %0\n"
 189                 : "=r" (sum), "=&r" (__dummy)
 190                 : "r" (saddr), "r" (daddr),
 191                   "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
 192                 : "t");
 193
 194         return csum_fold(sum);
 195 }
 196
 197 /*
 198  *      Copy and checksum to user
 199  */
 200 #define HAVE_CSUM_COPY_USER
 201 static inline __wsum csum_and_copy_to_user(const void *src,
 202                                            void __user *dst,
 203                                            int len, __wsum sum,
 204                                            int *err_ptr)
 205 {
 206         if (access_ok(VERIFY_WRITE, dst, len))
 207                 return csum_partial_copy_generic((__force const void *)src,
 208                                                 dst, len, sum, NULL, err_ptr);
 209
 210         if (len)
 211                 *err_ptr = -EFAULT;
 212
 213         return (__force __wsum)-1; /* invalid checksum */
 214 }
 215 #endif /* __ASM_SH_CHECKSUM_H */