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             : "cc"
  26             );
  27         return sum >> 16;
  28 }
  29
  30 __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  31 {
  32         return ~do_csum(iph, ihl * 4);
  33 }
  34 EXPORT_SYMBOL(ip_fast_csum);
  35
  36 __wsum csum_partial(const void *buff, int len, __wsum sum)
  37 {
  38         __wsum result;
  39
  40         result = do_csum(buff, len);
  41         result += sum;
  42         if (sum > result)
  43                 result++;
  44         return result;
  45 }
  46 EXPORT_SYMBOL(csum_partial);
  47
  48 __sum16 ip_compute_csum(const void *buff, int len)
  49 {
  50         return ~from32to16(do_csum(buff, len));
  51 }
  52 EXPORT_SYMBOL(ip_compute_csum);
  53
  54 __wsum csum_partial_copy(const void *src, void *dst, int len, __wsum sum)
  55 {
  56         copy_from_user(dst, src, len);
  57         return csum_partial(dst, len, sum);
  58 }
  59 EXPORT_SYMBOL(csum_partial_copy);
  60
  61 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
  62                                  int len, __wsum sum)
  63 {
  64         sum = csum_partial(src, len, sum);
  65         memcpy(dst, src, len);
  66         return sum;
  67 }
  68 EXPORT_SYMBOL(csum_partial_copy_nocheck);
  69
  70 __wsum csum_partial_copy_from_user(const void *src, void *dst,
  71                                    int len, __wsum sum,
  72                                    int *err_ptr)
  73 {
  74         int missing;
  75
  76         missing = copy_from_user(dst, src, len);
  77         if (missing) {
  78                 memset(dst + len - missing, 0, missing);
  79                 *err_ptr = -EFAULT;
  80         }
  81
  82         return csum_partial(dst, len, sum);
  83 }
  84 EXPORT_SYMBOL(csum_partial_copy_from_user);
  85
  86 __wsum csum_and_copy_to_user(const void *src, void *dst,
  87                              int len, __wsum sum,
  88                              int *err_ptr)
  89 {
  90         int missing;
  91
  92         missing = copy_to_user(dst, src, len);
  93         if (missing) {
  94                 memset(dst + len - missing, 0, missing);
  95                 *err_ptr = -EFAULT;
  96         }
  97
  98         return csum_partial(src, len, sum);
  99 }
 100 EXPORT_SYMBOL(csum_and_copy_to_user);