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 the TCP/UDP pseudo-header
  24  * returns a 16-bit checksum, already complemented
  25  */
  26 extern __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
  27                                         unsigned short len,
  28                                         unsigned short proto,
  29                                         __wsum sum);
  30
  31 /*
  32  * computes the checksum of a memory block at buff, length len,
  33  * and adds in "sum" (32-bit)
  34  *
  35  * returns a 32-bit number suitable for feeding into itself
  36  * or csum_tcpudp_magic
  37  *
  38  * this function must be called with even lengths, except
  39  * for the last fragment, which may be odd
  40  *
  41  * it's best to have buff aligned on a 32-bit boundary
  42  */
  43 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
  44
  45 /*
  46  * Computes the checksum of a memory block at src, length len,
  47  * and adds in "sum" (32-bit), while copying the block to dst.
  48  * If an access exception occurs on src or dst, it stores -EFAULT
  49  * to *src_err or *dst_err respectively (if that pointer is not
  50  * NULL), and, for an error on src, zeroes the rest of dst.
  51  *
  52  * Like csum_partial, this must be called with even lengths,
  53  * except for the last fragment.
  54  */
  55 extern __wsum csum_partial_copy_generic(const void *src, void *dst,
  56                                               int len, __wsum sum,
  57                                               int *src_err, int *dst_err);
  58
  59 #ifdef __powerpc64__
  60 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
  61 extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
  62                                       int len, __wsum sum, int *err_ptr);
  63 #define HAVE_CSUM_COPY_USER
  64 extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
  65                                     int len, __wsum sum, int *err_ptr);
  66 #else
  67 /*
  68  * the same as csum_partial, but copies from src to dst while it
  69  * checksums.
  70  */
  71 #define csum_partial_copy_from_user(src, dst, len, sum, errp)   \
  72         csum_partial_copy_generic((__force const void *)(src), (dst), (len), (sum), (errp), NULL)
  73 #endif
  74
  75 #define csum_partial_copy_nocheck(src, dst, len, sum)   \
  76         csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
  77
  78
  79 /*
  80  * turns a 32-bit partial checksum (e.g. from csum_partial) into a
  81  * 1's complement 16-bit checksum.
  82  */
  83 static inline __sum16 csum_fold(__wsum sum)
  84 {
  85         unsigned int tmp;
  86
  87         /* swap the two 16-bit halves of sum */
  88         __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
  89         /* if there is a carry from adding the two 16-bit halves,
  90            it will carry from the lower half into the upper half,
  91            giving us the correct sum in the upper half. */
  92         return (__force __sum16)(~((__force u32)sum + tmp) >> 16);
  93 }
  94
  95 /*
  96  * this routine is used for miscellaneous IP-like checksums, mainly
  97  * in icmp.c
  98  */
  99 static inline __sum16 ip_compute_csum(const void *buff, int len)
 100 {
 101         return csum_fold(csum_partial(buff, len, 0));
 102 }
 103
 104 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 105                                      unsigned short len,
 106                                      unsigned short proto,
 107                                      __wsum sum)
 108 {
 109 #ifdef __powerpc64__
 110         unsigned long s = (__force u32)sum;
 111
 112         s += (__force u32)saddr;
 113         s += (__force u32)daddr;
 114         s += proto + len;
 115         s += (s >> 32);
 116         return (__force __wsum) s;
 117 #else
 118     __asm__("\n\
 119         addc %0,%0,%1 \n\
 120         adde %0,%0,%2 \n\
 121         adde %0,%0,%3 \n\
 122         addze %0,%0 \n\
 123         "
 124         : "=r" (sum)
 125         : "r" (daddr), "r"(saddr), "r"(proto + len), "0"(sum));
 126         return sum;
 127 #endif
 128 }
 129
 130 #endif
 131 #endif /* __KERNEL__ */
 132 #endif