include/asm-s390/checksum.h

   1 #ifndef _S390_CHECKSUM_H
   2 #define _S390_CHECKSUM_H
   3
   4 /*
   5  *  include/asm-s390/checksum.h
   6  *    S390 fast network checksum routines
   7  *    see also arch/S390/lib/checksum.c
   8  *
   9  *  S390 version
  10  *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
  11  *    Author(s): Ulrich Hild        (first version)
  12  *               Martin Schwidefsky (heavily optimized CKSM version)
  13  *               D.J. Barrow        (third attempt)
  14  */
  15
  16 #include <asm/uaccess.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 static inline unsigned int
  31 csum_partial(const unsigned char * buff, int len, unsigned int sum)
  32 {
  33         /*
  34          * Experiments with ethernet and slip connections show that buf
  35          * is aligned on either a 2-byte or 4-byte boundary.
  36          */
  37 #ifndef __s390x__
  38         register_pair rp;
  39
  40         rp.subreg.even = (unsigned long) buff;
  41         rp.subreg.odd = (unsigned long) len;
  42         __asm__ __volatile__ (
  43                 "0:  cksm %0,%1\n"      /* do checksum on longs */
  44                 "    jo   0b\n"
  45                 : "+&d" (sum), "+&a" (rp) : : "cc", "memory" );
  46 #else /* __s390x__ */
  47         __asm__ __volatile__ (
  48                 "    lgr  2,%1\n"    /* address in gpr 2 */
  49                 "    lgfr 3,%2\n"    /* length in gpr 3 */
  50                 "0:  cksm %0,2\n"    /* do checksum on longs */
  51                 "    jo   0b\n"
  52                 : "+&d" (sum)
  53                 : "d" (buff), "d" (len)
  54                 : "cc", "memory", "2", "3" );
  55 #endif /* __s390x__ */
  56         return sum;
  57 }
  58
  59 /*
  60  * csum_partial as an inline function
  61  */
  62 static inline unsigned int
  63 csum_partial_inline(const unsigned char * buff, int len, unsigned int sum)
  64 {
  65 #ifndef __s390x__
  66         register_pair rp;
  67
  68         rp.subreg.even = (unsigned long) buff;
  69         rp.subreg.odd = (unsigned long) len;
  70         __asm__ __volatile__ (
  71                 "0:  cksm %0,%1\n"    /* do checksum on longs */
  72                 "    jo   0b\n"
  73                 : "+&d" (sum), "+&a" (rp) : : "cc", "memory" );
  74 #else /* __s390x__ */
  75         __asm__ __volatile__ (
  76                 "    lgr  2,%1\n"    /* address in gpr 2 */
  77                 "    lgfr 3,%2\n"    /* length in gpr 3 */
  78                 "0:  cksm %0,2\n"    /* do checksum on longs */
  79                 "    jo   0b\n"
  80                 : "+&d" (sum)
  81                 : "d" (buff), "d" (len)
  82                 : "cc", "memory", "2", "3" );
  83 #endif /* __s390x__ */
  84         return sum;
  85 }
  86
  87 /*
  88  * the same as csum_partial_copy, but copies from user space.
  89  *
  90  * here even more important to align src and dst on a 32-bit (or even
  91  * better 64-bit) boundary
  92  *
  93  * Copy from userspace and compute checksum.  If we catch an exception
  94  * then zero the rest of the buffer.
  95  */
  96 static inline unsigned int
  97 csum_partial_copy_from_user(const char __user *src, char *dst,
  98                                           int len, unsigned int sum,
  99                                           int *err_ptr)
 100 {
 101         int missing;
 102
 103         missing = copy_from_user(dst, src, len);
 104         if (missing) {
 105                 memset(dst + len - missing, 0, missing);
 106                 *err_ptr = -EFAULT;
 107         }
 108
 109         return csum_partial(dst, len, sum);
 110 }
 111
 112
 113 static inline unsigned int
 114 csum_partial_copy_nocheck (const char *src, char *dst, int len, unsigned int sum)
 115 {
 116         memcpy(dst,src,len);
 117         return csum_partial_inline(dst, len, sum);
 118 }
 119
 120 /*
 121  *      Fold a partial checksum without adding pseudo headers
 122  */
 123 static inline unsigned short
 124 csum_fold(unsigned int sum)
 125 {
 126 #ifndef __s390x__
 127         register_pair rp;
 128
 129         __asm__ __volatile__ (
 130                 "    slr  %N1,%N1\n" /* %0 = H L */
 131                 "    lr   %1,%0\n"   /* %0 = H L, %1 = H L 0 0 */
 132                 "    srdl %1,16\n"   /* %0 = H L, %1 = 0 H L 0 */
 133                 "    alr  %1,%N1\n"  /* %0 = H L, %1 = L H L 0 */
 134                 "    alr  %0,%1\n"   /* %0 = H+L+C L+H */
 135                 "    srl  %0,16\n"   /* %0 = H+L+C */
 136                 : "+&d" (sum), "=d" (rp) : : "cc" );
 137 #else /* __s390x__ */
 138         __asm__ __volatile__ (
 139                 "    sr   3,3\n"   /* %0 = H*65536 + L */
 140                 "    lr   2,%0\n"  /* %0 = H L, R2/R3 = H L / 0 0 */
 141                 "    srdl 2,16\n"  /* %0 = H L, R2/R3 = 0 H / L 0 */
 142                 "    alr  2,3\n"   /* %0 = H L, R2/R3 = L H / L 0 */
 143                 "    alr  %0,2\n"  /* %0 = H+L+C L+H */
 144                 "    srl  %0,16\n" /* %0 = H+L+C */
 145                 : "+&d" (sum) : : "cc", "2", "3");
 146 #endif /* __s390x__ */
 147         return ((unsigned short) ~sum);
 148 }
 149
 150 /*
 151  *      This is a version of ip_compute_csum() optimized for IP headers,
 152  *      which always checksum on 4 octet boundaries.
 153  *
 154  */
 155 static inline unsigned short
 156 ip_fast_csum(unsigned char *iph, unsigned int ihl)
 157 {
 158         unsigned long sum;
 159 #ifndef __s390x__
 160         register_pair rp;
 161
 162         rp.subreg.even = (unsigned long) iph;
 163         rp.subreg.odd = (unsigned long) ihl*4;
 164         __asm__ __volatile__ (
 165                 "    sr   %0,%0\n"   /* set sum to zero */
 166                 "0:  cksm %0,%1\n"   /* do checksum on longs */
 167                 "    jo   0b\n"
 168                 : "=&d" (sum), "+&a" (rp) : : "cc", "memory" );
 169 #else /* __s390x__ */
 170         __asm__ __volatile__ (
 171                 "    slgr %0,%0\n"   /* set sum to zero */
 172                 "    lgr  2,%1\n"    /* address in gpr 2 */
 173                 "    lgfr 3,%2\n"    /* length in gpr 3 */
 174                 "0:  cksm %0,2\n"    /* do checksum on ints */
 175                 "    jo   0b\n"
 176                 : "=&d" (sum)
 177                 : "d" (iph), "d" (ihl*4)
 178                 : "cc", "memory", "2", "3" );
 179 #endif /* __s390x__ */
 180         return csum_fold(sum);
 181 }
 182
 183 /*
 184  * computes the checksum of the TCP/UDP pseudo-header
 185  * returns a 32-bit checksum
 186  */
 187 static inline unsigned int
 188 csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr,
 189                    unsigned short len, unsigned short proto,
 190                    unsigned int sum)
 191 {
 192 #ifndef __s390x__
 193         __asm__ __volatile__ (
 194                 "    alr   %0,%1\n"  /* sum += saddr */
 195                 "    brc   12,0f\n"
 196                 "    ahi   %0,1\n"   /* add carry */
 197                 "0:"
 198                 : "+&d" (sum) : "d" (saddr) : "cc" );
 199         __asm__ __volatile__ (
 200                 "    alr   %0,%1\n"  /* sum += daddr */
 201                 "    brc   12,1f\n"
 202                 "    ahi   %0,1\n"   /* add carry */
 203                 "1:"
 204                 : "+&d" (sum) : "d" (daddr) : "cc" );
 205         __asm__ __volatile__ (
 206                 "    alr   %0,%1\n"  /* sum += (len<<16) + (proto<<8) */
 207                 "    brc   12,2f\n"
 208                 "    ahi   %0,1\n"   /* add carry */
 209                 "2:"
 210                 : "+&d" (sum)
 211                 : "d" (((unsigned int) len<<16) + (unsigned int) proto)
 212                 : "cc" );
 213 #else /* __s390x__ */
 214         __asm__ __volatile__ (
 215                 "    lgfr  %0,%0\n"
 216                 "    algr  %0,%1\n"  /* sum += saddr */
 217                 "    brc   12,0f\n"
 218                 "    aghi  %0,1\n"   /* add carry */
 219                 "0:  algr  %0,%2\n"  /* sum += daddr */
 220                 "    brc   12,1f\n"
 221                 "    aghi  %0,1\n"   /* add carry */
 222                 "1:  algfr %0,%3\n"  /* sum += (len<<16) + proto */
 223                 "    brc   12,2f\n"
 224                 "    aghi  %0,1\n"   /* add carry */
 225                 "2:  srlg  0,%0,32\n"
 226                 "    alr   %0,0\n"   /* fold to 32 bits */
 227                 "    brc   12,3f\n"
 228                 "    ahi   %0,1\n"   /* add carry */
 229                 "3:  llgfr %0,%0"
 230                 : "+&d" (sum)
 231                 : "d" (saddr), "d" (daddr),
 232                   "d" (((unsigned int) len<<16) + (unsigned int) proto)
 233                 : "cc", "0" );
 234 #endif /* __s390x__ */
 235         return sum;
 236 }
 237
 238 /*
 239  * computes the checksum of the TCP/UDP pseudo-header
 240  * returns a 16-bit checksum, already complemented
 241  */
 242
 243 static inline unsigned short int
 244 csum_tcpudp_magic(unsigned long saddr, unsigned long daddr,
 245                   unsigned short len, unsigned short proto,
 246                   unsigned int sum)
 247 {
 248         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 249 }
 250
 251 /*
 252  * this routine is used for miscellaneous IP-like checksums, mainly
 253  * in icmp.c
 254  */
 255
 256 static inline unsigned short
 257 ip_compute_csum(unsigned char * buff, int len)
 258 {
 259         return csum_fold(csum_partial(buff, len, 0));
 260 }
 261
 262 #endif /* _S390_CHECKSUM_H */
 263
 264