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            : "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}
  34EXPORT_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}
  46EXPORT_SYMBOL(csum_partial);
  47
  48__sum16 ip_compute_csum(const void *buff, int len)
  49{
  50        return ~from32to16(do_csum(buff, len));
  51}
  52EXPORT_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}
  59EXPORT_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}
  68EXPORT_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}
  84EXPORT_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}
 100EXPORT_SYMBOL(csum_and_copy_to_user);
 101