arch/powerpc/include/asm/checksum.h

   1 #ifndef _ASM_POWERPC_CHECKSUM_H
   2 #define _ASM_POWERPC_CHECKSUM_H
   3 #ifdef __KERNEL__
   4
   5 /*
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 /*
  13  * This is a version of ip_compute_csum() optimized for IP headers,
  14  * which always checksum on 4 octet boundaries.  ihl is the number
  15  * of 32-bit words and is always >= 5.
  16  */
  17 #ifdef CONFIG_GENERIC_CSUM
  18 #include <asm-generic/checksum.h>
  19 #else
  20 extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
  21
  22 /*
  23  * computes the checksum of a memory block at buff, length len,
  24  * and adds in "sum" (32-bit)
  25  *
  26  * returns a 32-bit number suitable for feeding into itself
  27  * or csum_tcpudp_magic
  28  *
  29  * this function must be called with even lengths, except
  30  * for the last fragment, which may be odd
  31  *
  32  * it's best to have buff aligned on a 32-bit boundary
  33  */
  34 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
  35
  36 /*
  37  * Computes the checksum of a memory block at src, length len,
  38  * and adds in "sum" (32-bit), while copying the block to dst.
  39  * If an access exception occurs on src or dst, it stores -EFAULT
  40  * to *src_err or *dst_err respectively (if that pointer is not
  41  * NULL), and, for an error on src, zeroes the rest of dst.
  42  *
  43  * Like csum_partial, this must be called with even lengths,
  44  * except for the last fragment.
  45  */
  46 extern __wsum csum_partial_copy_generic(const void *src, void *dst,
  47                                               int len, __wsum sum,
  48                                               int *src_err, int *dst_err);
  49
  50 #ifdef __powerpc64__
  51 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
  52 extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
  53                                       int len, __wsum sum, int *err_ptr);
  54 #define HAVE_CSUM_COPY_USER
  55 extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
  56                                     int len, __wsum sum, int *err_ptr);
  57 #else
  58 /*
  59  * the same as csum_partial, but copies from src to dst while it
  60  * checksums.
  61  */
  62 #define csum_partial_copy_from_user(src, dst, len, sum, errp)   \
  63         csum_partial_copy_generic((__force const void *)(src), (dst), (len), (sum), (errp), NULL)
  64 #endif
  65
  66 #define csum_partial_copy_nocheck(src, dst, len, sum)   \
  67         csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
  68
  69
  70 /*
  71  * turns a 32-bit partial checksum (e.g. from csum_partial) into a
  72  * 1's complement 16-bit checksum.
  73  */
  74 static inline __sum16 csum_fold(__wsum sum)
  75 {
  76         unsigned int tmp;
  77
  78         /* swap the two 16-bit halves of sum */
  79         __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
  80         /* if there is a carry from adding the two 16-bit halves,
  81            it will carry from the lower half into the upper half,
  82            giving us the correct sum in the upper half. */
  83         return (__force __sum16)(~((__force u32)sum + tmp) >> 16);
  84 }
  85
  86 /*
  87  * this routine is used for miscellaneous IP-like checksums, mainly
  88  * in icmp.c
  89  */
  90 static inline __sum16 ip_compute_csum(const void *buff, int len)
  91 {
  92         return csum_fold(csum_partial(buff, len, 0));
  93 }
  94
  95 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
  96                                      unsigned short len,
  97                                      unsigned short proto,
  98                                      __wsum sum)
  99 {
 100 #ifdef __powerpc64__
 101         unsigned long s = (__force u32)sum;
 102
 103         s += (__force u32)saddr;
 104         s += (__force u32)daddr;
 105         s += proto + len;
 106         s += (s >> 32);
 107         return (__force __wsum) s;
 108 #else
 109     __asm__("\n\
 110         addc %0,%0,%1 \n\
 111         adde %0,%0,%2 \n\
 112         adde %0,%0,%3 \n\
 113         addze %0,%0 \n\
 114         "
 115         : "=r" (sum)
 116         : "r" (daddr), "r"(saddr), "r"(proto + len), "0"(sum));
 117         return sum;
 118 #endif
 119 }
 120
 121 /*
 122  * computes the checksum of the TCP/UDP pseudo-header
 123  * returns a 16-bit checksum, already complemented
 124  */
 125 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 126                                         unsigned short len,
 127                                         unsigned short proto,
 128                                         __wsum sum)
 129 {
 130         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
 131 }
 132
 133 #define HAVE_ARCH_CSUM_ADD
 134 static inline __wsum csum_add(__wsum csum, __wsum addend)
 135 {
 136 #ifdef __powerpc64__
 137         u64 res = (__force u64)csum;
 138
 139         res += (__force u64)addend;
 140         return (__force __wsum)((u32)res + (res >> 32));
 141 #else
 142         asm("addc %0,%0,%1;"
 143             "addze %0,%0;"
 144             : "+r" (csum) : "r" (addend));
 145         return csum;
 146 #endif
 147 }
 148
 149 #endif
 150 #endif /* __KERNEL__ */
 151 #endif