arch/mn10300/lib/checksum.c

   1 /* MN10300 Optimised checksumming wrappers
   2  *
   3  * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
   4  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public Licence
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the Licence, or (at your option) any later version.
  11  */
  12 #include <linux/module.h>
  13 #include <linux/errno.h>
  14 #include <asm/byteorder.h>
  15 #include <asm/uaccess.h>
  16 #include <asm/checksum.h>
  17 #include "internal.h"
  18
  19 static inline unsigned short from32to16(__wsum sum)
  20 {
  21         asm("   add     %1,%0           \n"
  22             "   addc    0xffff,%0       \n"
  23             : "=r" (sum)
  24             : "r" (sum << 16), "0" (sum & 0xffff0000)
  25             );
  26         return sum >> 16;
  27 }
  28
  29 __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  30 {
  31         return ~do_csum(iph, ihl * 4);
  32 }
  33 EXPORT_SYMBOL(ip_fast_csum);
  34
  35 __wsum csum_partial(const void *buff, int len, __wsum sum)
  36 {
  37         __wsum result;
  38
  39         result = do_csum(buff, len);
  40         result += sum;
  41         if (sum > result)
  42                 result++;
  43         return result;
  44 }
  45 EXPORT_SYMBOL(csum_partial);
  46
  47 __sum16 ip_compute_csum(const void *buff, int len)
  48 {
  49         return ~from32to16(do_csum(buff, len));
  50 }
  51 EXPORT_SYMBOL(ip_compute_csum);
  52
  53 __wsum csum_partial_copy(const void *src, void *dst, int len, __wsum sum)
  54 {
  55         copy_from_user(dst, src, len);
  56         return csum_partial(dst, len, sum);
  57 }
  58 EXPORT_SYMBOL(csum_partial_copy);
  59
  60 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
  61                                  int len, __wsum sum)
  62 {
  63         sum = csum_partial(src, len, sum);
  64         memcpy(dst, src, len);
  65         return sum;
  66 }
  67 EXPORT_SYMBOL(csum_partial_copy_nocheck);
  68
  69 __wsum csum_partial_copy_from_user(const void *src, void *dst,
  70                                    int len, __wsum sum,
  71                                    int *err_ptr)
  72 {
  73         int missing;
  74
  75         missing = copy_from_user(dst, src, len);
  76         if (missing) {
  77                 memset(dst + len - missing, 0, missing);
  78                 *err_ptr = -EFAULT;
  79         }
  80
  81         return csum_partial(dst, len, sum);
  82 }
  83 EXPORT_SYMBOL(csum_partial_copy_from_user);
  84
  85 __wsum csum_and_copy_to_user(const void *src, void *dst,
  86                              int len, __wsum sum,
  87                              int *err_ptr)
  88 {
  89         int missing;
  90
  91         missing = copy_to_user(dst, src, len);
  92         if (missing) {
  93                 memset(dst + len - missing, 0, missing);
  94                 *err_ptr = -EFAULT;
  95         }
  96
  97         return csum_partial(src, len, sum);
  98 }
  99 EXPORT_SYMBOL(csum_and_copy_to_user);