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kernel/linux-imx6_3.14.28/arch/mn10300/lib/checksum.c 2.29 KB
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  /* MN10300 Optimised checksumming wrappers
   *
   * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
   * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public Licence
   * as published by the Free Software Foundation; either version
   * 2 of the Licence, or (at your option) any later version.
   */
  #include <linux/module.h>
  #include <linux/errno.h>
  #include <asm/byteorder.h>
  #include <asm/uaccess.h>
  #include <asm/checksum.h>
  #include "internal.h"
  
  static inline unsigned short from32to16(__wsum sum)
  {
  	asm("	add	%1,%0		
  "
  	    "	addc	0xffff,%0	
  "
  	    : "=r" (sum)
  	    : "r" (sum << 16), "0" (sum & 0xffff0000)
  	    : "cc"
  	    );
  	return sum >> 16;
  }
  
  __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  {
  	return ~do_csum(iph, ihl * 4);
  }
  EXPORT_SYMBOL(ip_fast_csum);
  
  __wsum csum_partial(const void *buff, int len, __wsum sum)
  {
  	__wsum result;
  
  	result = do_csum(buff, len);
  	result += sum;
  	if (sum > result)
  		result++;
  	return result;
  }
  EXPORT_SYMBOL(csum_partial);
  
  __sum16 ip_compute_csum(const void *buff, int len)
  {
  	return ~from32to16(do_csum(buff, len));
  }
  EXPORT_SYMBOL(ip_compute_csum);
  
  __wsum csum_partial_copy(const void *src, void *dst, int len, __wsum sum)
  {
  	copy_from_user(dst, src, len);
  	return csum_partial(dst, len, sum);
  }
  EXPORT_SYMBOL(csum_partial_copy);
  
  __wsum csum_partial_copy_nocheck(const void *src, void *dst,
  				 int len, __wsum sum)
  {
  	sum = csum_partial(src, len, sum);
  	memcpy(dst, src, len);
  	return sum;
  }
  EXPORT_SYMBOL(csum_partial_copy_nocheck);
  
  __wsum csum_partial_copy_from_user(const void *src, void *dst,
  				   int len, __wsum sum,
  				   int *err_ptr)
  {
  	int missing;
  
  	missing = copy_from_user(dst, src, len);
  	if (missing) {
  		memset(dst + len - missing, 0, missing);
  		*err_ptr = -EFAULT;
  	}
  
  	return csum_partial(dst, len, sum);
  }
  EXPORT_SYMBOL(csum_partial_copy_from_user);
  
  __wsum csum_and_copy_to_user(const void *src, void *dst,
  			     int len, __wsum sum,
  			     int *err_ptr)
  {
  	int missing;
  
  	missing = copy_to_user(dst, src, len);
  	if (missing) {
  		memset(dst + len - missing, 0, missing);
  		*err_ptr = -EFAULT;
  	}
  
  	return csum_partial(src, len, sum);
  }
  EXPORT_SYMBOL(csum_and_copy_to_user);