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