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/config.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 unsigned int csum_partial(const unsigned char * buff, int len, unsigned int 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 unsigned int csum_partial_copy_generic( const char *src, char *dst, int len, int sum,
  37                                                    int *src_err_ptr, int *dst_err_ptr);
  38
  39 /*
  40  *      Note: when you get a NULL pointer exception here this means someone
  41  *      passed in an incorrect kernel address to one of these functions.
  42  *
  43  *      If you use these functions directly please don't forget the
  44  *      verify_area().
  45  */
  46 static __inline__
  47 unsigned int csum_partial_copy_nocheck ( const char *src, char *dst,
  48                                         int len, int sum)
  49 {
  50         return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);
  51 }
  52
  53 static __inline__
  54 unsigned int csum_partial_copy_from_user ( const char *src, char *dst,
  55                                                 int len, int sum, int *err_ptr)
  56 {
  57         return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, NULL);
  58 }
  59
  60 /*
  61  *      Fold a partial checksum
  62  */
  63
  64 static __inline__ unsigned int csum_fold(unsigned int sum)
  65 {
  66         unsigned int __dummy;
  67         __asm__("swap.w %0, %1\n\t"
  68                 "extu.w %0, %0\n\t"
  69                 "extu.w %1, %1\n\t"
  70                 "add    %1, %0\n\t"
  71                 "swap.w %0, %1\n\t"
  72                 "add    %1, %0\n\t"
  73                 "not    %0, %0\n\t"
  74                 : "=r" (sum), "=&r" (__dummy)
  75                 : "0" (sum)
  76                 : "t");
  77         return sum;
  78 }
  79
  80 /*
  81  *      This is a version of ip_compute_csum() optimized for IP headers,
  82  *      which always checksum on 4 octet boundaries.
  83  *
  84  *      i386 version by Jorge Cwik <jorge@laser.satlink.net>, adapted
  85  *      for linux by * Arnt Gulbrandsen.
  86  */
  87 static __inline__ unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl)
  88 {
  89         unsigned int sum, __dummy0, __dummy1;
  90
  91         __asm__ __volatile__(
  92                 "mov.l  @%1+, %0\n\t"
  93                 "mov.l  @%1+, %3\n\t"
  94                 "add    #-2, %2\n\t"
  95                 "clrt\n\t"
  96                 "1:\t"
  97                 "addc   %3, %0\n\t"
  98                 "movt   %4\n\t"
  99                 "mov.l  @%1+, %3\n\t"
 100                 "dt     %2\n\t"
 101                 "bf/s   1b\n\t"
 102                 " cmp/eq #1, %4\n\t"
 103                 "addc   %3, %0\n\t"
 104                 "addc   %2, %0"     /* Here %2 is 0, add carry-bit */
 105         /* Since the input registers which are loaded with iph and ihl
 106            are modified, we must also specify them as outputs, or gcc
 107            will assume they contain their original values. */
 108         : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (__dummy0), "=&z" (__dummy1)
 109         : "1" (iph), "2" (ihl)
 110         : "t");
 111
 112         return  csum_fold(sum);
 113 }
 114
 115 static __inline__ unsigned long csum_tcpudp_nofold(unsigned long saddr,
 116                                                    unsigned long daddr,
 117                                                    unsigned short len,
 118                                                    unsigned short proto,
 119                                                    unsigned int sum)
 120 {
 121 #ifdef __LITTLE_ENDIAN__
 122         unsigned long len_proto = (ntohs(len)<<16)+proto*256;
 123 #else
 124         unsigned long len_proto = (proto<<16)+len;
 125 #endif
 126         __asm__("clrt\n\t"
 127                 "addc   %0, %1\n\t"
 128                 "addc   %2, %1\n\t"
 129                 "addc   %3, %1\n\t"
 130                 "movt   %0\n\t"
 131                 "add    %1, %0"
 132                 : "=r" (sum), "=r" (len_proto)
 133                 : "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum)
 134                 : "t");
 135         return sum;
 136 }
 137
 138 /*
 139  * computes the checksum of the TCP/UDP pseudo-header
 140  * returns a 16-bit checksum, already complemented
 141  */
 142 static __inline__ unsigned short int csum_tcpudp_magic(unsigned long saddr,
 143                                                        unsigned long daddr,
 144                                                        unsigned short len,
 145                                                        unsigned short proto,
 146                                                        unsigned int sum)
 147 {
 148         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 149 }
 150
 151 /*
 152  * this routine is used for miscellaneous IP-like checksums, mainly
 153  * in icmp.c
 154  */
 155
 156 static __inline__ unsigned short ip_compute_csum(unsigned char * buff, int len)
 157 {
 158     return csum_fold (csum_partial(buff, len, 0));
 159 }
 160
 161 #define _HAVE_ARCH_IPV6_CSUM
 162 #ifdef CONFIG_IPV6
 163 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
 164                                                      struct in6_addr *daddr,
 165                                                      __u32 len,
 166                                                      unsigned short proto,
 167                                                      unsigned int sum)
 168 {
 169         unsigned int __dummy;
 170         __asm__("clrt\n\t"
 171                 "mov.l  @(0,%2), %1\n\t"
 172                 "addc   %1, %0\n\t"
 173                 "mov.l  @(4,%2), %1\n\t"
 174                 "addc   %1, %0\n\t"
 175                 "mov.l  @(8,%2), %1\n\t"
 176                 "addc   %1, %0\n\t"
 177                 "mov.l  @(12,%2), %1\n\t"
 178                 "addc   %1, %0\n\t"
 179                 "mov.l  @(0,%3), %1\n\t"
 180                 "addc   %1, %0\n\t"
 181                 "mov.l  @(4,%3), %1\n\t"
 182                 "addc   %1, %0\n\t"
 183                 "mov.l  @(8,%3), %1\n\t"
 184                 "addc   %1, %0\n\t"
 185                 "mov.l  @(12,%3), %1\n\t"
 186                 "addc   %1, %0\n\t"
 187                 "addc   %4, %0\n\t"
 188                 "addc   %5, %0\n\t"
 189                 "movt   %1\n\t"
 190                 "add    %1, %0\n"
 191                 : "=r" (sum), "=&r" (__dummy)
 192                 : "r" (saddr), "r" (daddr),
 193                   "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
 194                 : "t");
 195
 196         return csum_fold(sum);
 197 }
 198 #endif
 199
 200 /*
 201  *      Copy and checksum to user
 202  */
 203 #define HAVE_CSUM_COPY_USER
 204 static __inline__ unsigned int csum_and_copy_to_user (const char *src,
 205                                                       char __user *dst,
 206                                                       int len, int sum,
 207                                                       int *err_ptr)
 208 {
 209         if (access_ok(VERIFY_WRITE, dst, len))
 210                 return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);
 211
 212         if (len)
 213                 *err_ptr = -EFAULT;
 214
 215         return -1; /* invalid checksum */
 216 }
 217 #endif /* __ASM_SH_CHECKSUM_H */