1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright 2002, 2003 Andi Kleen, SuSE Labs. 4 * 5 * Wrappers of assembly checksum functions for x86-64. 6 */ 7 #include <asm/checksum.h> 8 #include <linux/export.h> 9 #include <linux/uaccess.h> 10 #include <asm/smap.h> 11 12 /** 13 * csum_and_copy_from_user - Copy and checksum from user space. 14 * @src: source address (user space) 15 * @dst: destination address 16 * @len: number of bytes to be copied. 17 * @isum: initial sum that is added into the result (32bit unfolded) 18 * @errp: set to -EFAULT for an bad source address. 19 * 20 * Returns an 32bit unfolded checksum of the buffer. 21 * src and dst are best aligned to 64bits. 22 */ 23 __wsum 24 csum_and_copy_from_user(const void __user *src, void *dst, int len) 25 { 26 __wsum sum; 27 28 might_sleep(); 29 if (!user_access_begin(src, len)) 30 return 0; 31 sum = csum_partial_copy_generic((__force const void *)src, dst, len); 32 user_access_end(); 33 return sum; 34 } 35 EXPORT_SYMBOL(csum_and_copy_from_user); 36 37 /** 38 * csum_and_copy_to_user - Copy and checksum to user space. 39 * @src: source address 40 * @dst: destination address (user space) 41 * @len: number of bytes to be copied. 42 * @isum: initial sum that is added into the result (32bit unfolded) 43 * @errp: set to -EFAULT for an bad destination address. 44 * 45 * Returns an 32bit unfolded checksum of the buffer. 46 * src and dst are best aligned to 64bits. 47 */ 48 __wsum 49 csum_and_copy_to_user(const void *src, void __user *dst, int len) 50 { 51 __wsum sum; 52 53 might_sleep(); 54 if (!user_access_begin(dst, len)) 55 return 0; 56 sum = csum_partial_copy_generic(src, (void __force *)dst, len); 57 user_access_end(); 58 return sum; 59 } 60 EXPORT_SYMBOL(csum_and_copy_to_user); 61 62 /** 63 * csum_partial_copy_nocheck - Copy and checksum. 64 * @src: source address 65 * @dst: destination address 66 * @len: number of bytes to be copied. 67 * @sum: initial sum that is added into the result (32bit unfolded) 68 * 69 * Returns an 32bit unfolded checksum of the buffer. 70 */ 71 __wsum 72 csum_partial_copy_nocheck(const void *src, void *dst, int len) 73 { 74 return csum_partial_copy_generic(src, dst, len); 75 } 76 EXPORT_SYMBOL(csum_partial_copy_nocheck); 77 78 __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 79 const struct in6_addr *daddr, 80 __u32 len, __u8 proto, __wsum sum) 81 { 82 __u64 rest, sum64; 83 84 rest = (__force __u64)htonl(len) + (__force __u64)htons(proto) + 85 (__force __u64)sum; 86 87 asm(" addq (%[saddr]),%[sum]\n" 88 " adcq 8(%[saddr]),%[sum]\n" 89 " adcq (%[daddr]),%[sum]\n" 90 " adcq 8(%[daddr]),%[sum]\n" 91 " adcq $0,%[sum]\n" 92 93 : [sum] "=r" (sum64) 94 : "[sum]" (rest), [saddr] "r" (saddr), [daddr] "r" (daddr)); 95 96 return csum_fold( 97 (__force __wsum)add32_with_carry(sum64 & 0xffffffff, sum64>>32)); 98 } 99 EXPORT_SYMBOL(csum_ipv6_magic); 100