LXR linux/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
  19static 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}
  33EXPORT_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}
  45EXPORT_SYMBOL(csum_partial);
  46
  47__sum16 ip_compute_csum(const void *buff, int len)
  48{
  49        return ~from32to16(do_csum(buff, len));
  50}
  51EXPORT_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}
  58EXPORT_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}
  67EXPORT_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}
  83EXPORT_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}
  99EXPORT_SYMBOL(csum_and_copy_to_user);
 100