release/src-rt-6.x.4708/linux/linux-2.6.36/arch/parisc/include/asm/checksum.h

   1 #ifndef _PARISC_CHECKSUM_H
   2 #define _PARISC_CHECKSUM_H
   3
   4 #include <linux/in6.h>
   5
   6 /*
   7  * computes the checksum of a memory block at buff, length len,
   8  * and adds in "sum" (32-bit)
   9  *
  10  * returns a 32-bit number suitable for feeding into itself
  11  * or csum_tcpudp_magic
  12  *
  13  * this function must be called with even lengths, except
  14  * for the last fragment, which may be odd
  15  *
  16  * it's best to have buff aligned on a 32-bit boundary
  17  */
  18 extern __wsum csum_partial(const void *, int, __wsum);
  19
  20 /*
  21  * The same as csum_partial, but copies from src while it checksums.
  22  *
  23  * Here even more important to align src and dst on a 32-bit (or even
  24  * better 64-bit) boundary
  25  */
  26 extern __wsum csum_partial_copy_nocheck(const void *, void *, int, __wsum);
  27
  28 /*
  29  * this is a new version of the above that records errors it finds in *errp,
  30  * but continues and zeros the rest of the buffer.
  31  */
  32 extern __wsum csum_partial_copy_from_user(const void __user *src,
  33                 void *dst, int len, __wsum sum, int *errp);
  34
  35 /*
  36  *      Optimized for IP headers, which always checksum on 4 octet boundaries.
  37  *
  38  *      Written by Randolph Chung <tausq@debian.org>, and then mucked with by
  39  *      LaMont Jones <lamont@debian.org>
  40  */
  41 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  42 {
  43         unsigned int sum;
  44
  45         __asm__ __volatile__ (
  46 "       ldws,ma         4(%1), %0\n"
  47 "       addib,<=        -4, %2, 2f\n"
  48 "\n"
  49 "       ldws            4(%1), %%r20\n"
  50 "       ldws            8(%1), %%r21\n"
  51 "       add             %0, %%r20, %0\n"
  52 "       ldws,ma         12(%1), %%r19\n"
  53 "       addc            %0, %%r21, %0\n"
  54 "       addc            %0, %%r19, %0\n"
  55 "1:     ldws,ma         4(%1), %%r19\n"
  56 "       addib,<         0, %2, 1b\n"
  57 "       addc            %0, %%r19, %0\n"
  58 "\n"
  59 "       extru           %0, 31, 16, %%r20\n"
  60 "       extru           %0, 15, 16, %%r21\n"
  61 "       addc            %%r20, %%r21, %0\n"
  62 "       extru           %0, 15, 16, %%r21\n"
  63 "       add             %0, %%r21, %0\n"
  64 "       subi            -1, %0, %0\n"
  65 "2:\n"
  66         : "=r" (sum), "=r" (iph), "=r" (ihl)
  67         : "1" (iph), "2" (ihl)
  68         : "r19", "r20", "r21", "memory");
  69
  70         return (__force __sum16)sum;
  71 }
  72
  73 /*
  74  *      Fold a partial checksum
  75  */
  76 static inline __sum16 csum_fold(__wsum csum)
  77 {
  78         u32 sum = (__force u32)csum;
  79         /* add the swapped two 16-bit halves of sum,
  80            a possible carry from adding the two 16-bit halves,
  81            will carry from the lower half into the upper half,
  82            giving us the correct sum in the upper half. */
  83         sum += (sum << 16) + (sum >> 16);
  84         return (__force __sum16)(~sum >> 16);
  85 }
  86
  87 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
  88                                                unsigned short len,
  89                                                unsigned short proto,
  90                                                __wsum sum)
  91 {
  92         __asm__(
  93         "       add  %1, %0, %0\n"
  94         "       addc %2, %0, %0\n"
  95         "       addc %3, %0, %0\n"
  96         "       addc %%r0, %0, %0\n"
  97                 : "=r" (sum)
  98                 : "r" (daddr), "r"(saddr), "r"(proto+len), "0"(sum));
  99         return sum;
 100 }
 101
 102 /*
 103  * computes the checksum of the TCP/UDP pseudo-header
 104  * returns a 16-bit checksum, already complemented
 105  */
 106 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 107                                                    unsigned short len,
 108                                                    unsigned short proto,
 109                                                    __wsum sum)
 110 {
 111         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 112 }
 113
 114 /*
 115  * this routine is used for miscellaneous IP-like checksums, mainly
 116  * in icmp.c
 117  */
 118 static inline __sum16 ip_compute_csum(const void *buf, int len)
 119 {
 120          return csum_fold (csum_partial(buf, len, 0));
 121 }
 122
 123
 124 #define _HAVE_ARCH_IPV6_CSUM
 125 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 126                                           const struct in6_addr *daddr,
 127                                           __u32 len, unsigned short proto,
 128                                           __wsum sum)
 129 {
 130         __asm__ __volatile__ (
 131
 132 #if BITS_PER_LONG > 32
 133
 134         /*
 135         ** We can execute two loads and two adds per cycle on PA 8000.
 136         ** But add insn's get serialized waiting for the carry bit.
 137         ** Try to keep 4 registers with "live" values ahead of the ALU.
 138         */
 139
 140 "       ldd,ma          8(%1), %%r19\n" /* get 1st saddr word */
 141 "       ldd,ma          8(%2), %%r20\n" /* get 1st daddr word */
 142 "       add             %8, %3, %3\n"/* add 16-bit proto + len */
 143 "       add             %%r19, %0, %0\n"
 144 "       ldd,ma          8(%1), %%r21\n" /* 2cd saddr */
 145 "       ldd,ma          8(%2), %%r22\n" /* 2cd daddr */
 146 "       add,dc          %%r20, %0, %0\n"
 147 "       add,dc          %%r21, %0, %0\n"
 148 "       add,dc          %%r22, %0, %0\n"
 149 "       add,dc          %3, %0, %0\n"  /* fold in proto+len | carry bit */
 150 "       extrd,u         %0, 31, 32, %%r19\n"    /* copy upper half down */
 151 "       depdi           0, 31, 32, %0\n"        /* clear upper half */
 152 "       add             %%r19, %0, %0\n"        /* fold into 32-bits */
 153 "       addc            0, %0, %0\n"            /* add carry */
 154
 155 #else
 156
 157         /*
 158         ** For PA 1.x, the insn order doesn't matter as much.
 159         ** Insn stream is serialized on the carry bit here too.
 160         ** result from the previous operation (eg r0 + x)
 161         */
 162
 163 "       ldw,ma          4(%1), %%r19\n" /* get 1st saddr word */
 164 "       ldw,ma          4(%2), %%r20\n" /* get 1st daddr word */
 165 "       add             %8, %3, %3\n"   /* add 16-bit proto + len */
 166 "       add             %%r19, %0, %0\n"
 167 "       ldw,ma          4(%1), %%r21\n" /* 2cd saddr */
 168 "       addc            %%r20, %0, %0\n"
 169 "       ldw,ma          4(%2), %%r22\n" /* 2cd daddr */
 170 "       addc            %%r21, %0, %0\n"
 171 "       ldw,ma          4(%1), %%r19\n" /* 3rd saddr */
 172 "       addc            %%r22, %0, %0\n"
 173 "       ldw,ma          4(%2), %%r20\n" /* 3rd daddr */
 174 "       addc            %%r19, %0, %0\n"
 175 "       ldw,ma          4(%1), %%r21\n" /* 4th saddr */
 176 "       addc            %%r20, %0, %0\n"
 177 "       ldw,ma          4(%2), %%r22\n" /* 4th daddr */
 178 "       addc            %%r21, %0, %0\n"
 179 "       addc            %%r22, %0, %0\n"
 180 "       addc            %3, %0, %0\n"   /* fold in proto+len, catch carry */
 181
 182 #endif
 183         : "=r" (sum), "=r" (saddr), "=r" (daddr), "=r" (len)
 184         : "0" (sum), "1" (saddr), "2" (daddr), "3" (len), "r" (proto)
 185         : "r19", "r20", "r21", "r22", "memory");
 186         return csum_fold(sum);
 187 }
 188
 189 /*
 190  *      Copy and checksum to user
 191  */
 192 #define HAVE_CSUM_COPY_USER
 193 static __inline__ __wsum csum_and_copy_to_user(const void *src,
 194                                                       void __user *dst,
 195                                                       int len, __wsum sum,
 196                                                       int *err_ptr)
 197 {
 198         /* code stolen from include/asm-mips64 */
 199         sum = csum_partial(src, len, sum);
 200
 201         if (copy_to_user(dst, src, len)) {
 202                 *err_ptr = -EFAULT;
 203                 return (__force __wsum)-1;
 204         }
 205
 206         return sum;
 207 }
 208
 209 #endif