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         register unsigned long reg2 asm("2") = (unsigned long) buff;
  34         register unsigned long reg3 asm("3") = (unsigned long) len;
  35
  36         asm volatile(
  37                 "0:     cksm    %0,%1\n"        /* do checksum on longs */
  38                 "       jo      0b\n"
  39                 : "+d" (sum), "+d" (reg2), "+d" (reg3) : : "cc", "memory");
  40         return sum;
  41 }
  42
  43 /*
  44  * the same as csum_partial_copy, but copies from user space.
  45  *
  46  * here even more important to align src and dst on a 32-bit (or even
  47  * better 64-bit) boundary
  48  *
  49  * Copy from userspace and compute checksum.  If we catch an exception
  50  * then zero the rest of the buffer.
  51  */
  52 static inline unsigned int
  53 csum_partial_copy_from_user(const char __user *src, char *dst,
  54                                           int len, unsigned int sum,
  55                                           int *err_ptr)
  56 {
  57         int missing;
  58
  59         missing = copy_from_user(dst, src, len);
  60         if (missing) {
  61                 memset(dst + len - missing, 0, missing);
  62                 *err_ptr = -EFAULT;
  63         }
  64
  65         return csum_partial(dst, len, sum);
  66 }
  67
  68
  69 static inline unsigned int
  70 csum_partial_copy_nocheck (const char *src, char *dst, int len, unsigned int sum)
  71 {
  72         memcpy(dst,src,len);
  73         return csum_partial(dst, len, sum);
  74 }
  75
  76 /*
  77  *      Fold a partial checksum without adding pseudo headers
  78  */
  79 static inline unsigned short
  80 csum_fold(unsigned int sum)
  81 {
  82 #ifndef __s390x__
  83         register_pair rp;
  84
  85         asm volatile(
  86                 "       slr     %N1,%N1\n"      /* %0 = H L */
  87                 "       lr      %1,%0\n"        /* %0 = H L, %1 = H L 0 0 */
  88                 "       srdl    %1,16\n"        /* %0 = H L, %1 = 0 H L 0 */
  89                 "       alr     %1,%N1\n"       /* %0 = H L, %1 = L H L 0 */
  90                 "       alr     %0,%1\n"        /* %0 = H+L+C L+H */
  91                 "       srl     %0,16\n"        /* %0 = H+L+C */
  92                 : "+&d" (sum), "=d" (rp) : : "cc");
  93 #else /* __s390x__ */
  94         asm volatile(
  95                 "       sr      3,3\n"          /* %0 = H*65536 + L */
  96                 "       lr      2,%0\n"         /* %0 = H L, 2/3 = H L / 0 0 */
  97                 "       srdl    2,16\n"         /* %0 = H L, 2/3 = 0 H / L 0 */
  98                 "       alr     2,3\n"          /* %0 = H L, 2/3 = L H / L 0 */
  99                 "       alr     %0,2\n"         /* %0 = H+L+C L+H */
 100                 "       srl     %0,16\n"        /* %0 = H+L+C */
 101                 : "+&d" (sum) : : "cc", "2", "3");
 102 #endif /* __s390x__ */
 103         return ((unsigned short) ~sum);
 104 }
 105
 106 /*
 107  *      This is a version of ip_compute_csum() optimized for IP headers,
 108  *      which always checksum on 4 octet boundaries.
 109  *
 110  */
 111 static inline unsigned short
 112 ip_fast_csum(unsigned char *iph, unsigned int ihl)
 113 {
 114         return csum_fold(csum_partial(iph, ihl*4, 0));
 115 }
 116
 117 /*
 118  * computes the checksum of the TCP/UDP pseudo-header
 119  * returns a 32-bit checksum
 120  */
 121 static inline unsigned int
 122 csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr,
 123                    unsigned short len, unsigned short proto,
 124                    unsigned int sum)
 125 {
 126 #ifndef __s390x__
 127         asm volatile(
 128                 "       alr     %0,%1\n" /* sum += saddr */
 129                 "       brc     12,0f\n"
 130                 "       ahi     %0,1\n"  /* add carry */
 131                 "0:"
 132                 : "+&d" (sum) : "d" (saddr) : "cc");
 133         asm volatile(
 134                 "       alr     %0,%1\n" /* sum += daddr */
 135                 "       brc     12,1f\n"
 136                 "       ahi     %0,1\n"  /* add carry */
 137                 "1:"
 138                 : "+&d" (sum) : "d" (daddr) : "cc");
 139         asm volatile(
 140                 "       alr     %0,%1\n" /* sum += (len<<16) + (proto<<8) */
 141                 "       brc     12,2f\n"
 142                 "       ahi     %0,1\n"  /* add carry */
 143                 "2:"
 144                 : "+&d" (sum)
 145                 : "d" (((unsigned int) len<<16) + (unsigned int) proto)
 146                 : "cc");
 147 #else /* __s390x__ */
 148         asm volatile(
 149                 "       lgfr    %0,%0\n"
 150                 "       algr    %0,%1\n"  /* sum += saddr */
 151                 "       brc     12,0f\n"
 152                 "       aghi    %0,1\n"   /* add carry */
 153                 "0:     algr    %0,%2\n"  /* sum += daddr */
 154                 "       brc     12,1f\n"
 155                 "       aghi    %0,1\n"   /* add carry */
 156                 "1:     algfr   %0,%3\n"  /* sum += (len<<16) + proto */
 157                 "       brc     12,2f\n"
 158                 "       aghi    %0,1\n"   /* add carry */
 159                 "2:     srlg    0,%0,32\n"
 160                 "       alr     %0,0\n"   /* fold to 32 bits */
 161                 "       brc     12,3f\n"
 162                 "       ahi     %0,1\n"   /* add carry */
 163                 "3:     llgfr   %0,%0"
 164                 : "+&d" (sum)
 165                 : "d" (saddr), "d" (daddr),
 166                   "d" (((unsigned int) len<<16) + (unsigned int) proto)
 167                 : "cc", "0");
 168 #endif /* __s390x__ */
 169         return sum;
 170 }
 171
 172 /*
 173  * computes the checksum of the TCP/UDP pseudo-header
 174  * returns a 16-bit checksum, already complemented
 175  */
 176
 177 static inline unsigned short int
 178 csum_tcpudp_magic(unsigned long saddr, unsigned long daddr,
 179                   unsigned short len, unsigned short proto,
 180                   unsigned int sum)
 181 {
 182         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 183 }
 184
 185 /*
 186  * this routine is used for miscellaneous IP-like checksums, mainly
 187  * in icmp.c
 188  */
 189
 190 static inline unsigned short
 191 ip_compute_csum(unsigned char * buff, int len)
 192 {
 193         return csum_fold(csum_partial(buff, len, 0));
 194 }
 195
 196 #endif /* _S390_CHECKSUM_H */
 197
 198