1 /* 2 * Copyright 2002, 2003 Andi Kleen, SuSE Labs. 3 * Subject to the GNU Public License v.2 4 * 5 * Wrappers of assembly checksum functions for x86-64. 6 */ 7 #include <asm/checksum.h> 8 #include <linux/module.h> 9 10 /** 11 * csum_partial_copy_from_user - Copy and checksum from user space. 12 * @src: source address (user space) 13 * @dst: destination address 14 * @len: number of bytes to be copied. 15 * @isum: initial sum that is added into the result (32bit unfolded) 16 * @errp: set to -EFAULT for an bad source address. 17 * 18 * Returns an 32bit unfolded checksum of the buffer. 19 * src and dst are best aligned to 64bits. 20 */ 21 __wsum 22 csum_partial_copy_from_user(const void __user *src, void *dst, 23 int len, __wsum isum, int *errp) 24 { 25 might_sleep(); 26 *errp = 0; 27 28 if (!likely(access_ok(VERIFY_READ, src, len))) 29 goto out_err; 30 31 /* 32 * Why 6, not 7? To handle odd addresses aligned we 33 * would need to do considerable complications to fix the 34 * checksum which is defined as an 16bit accumulator. The 35 * fix alignment code is primarily for performance 36 * compatibility with 32bit and that will handle odd 37 * addresses slowly too. 38 */ 39 if (unlikely((unsigned long)src & 6)) { 40 while (((unsigned long)src & 6) && len >= 2) { 41 __u16 val16; 42 43 *errp = __get_user(val16, (const __u16 __user *)src); 44 if (*errp) 45 return isum; 46 47 *(__u16 *)dst = val16; 48 isum = (__force __wsum)add32_with_carry( 49 (__force unsigned)isum, val16); 50 src += 2; 51 dst += 2; 52 len -= 2; 53 } 54 } 55 isum = csum_partial_copy_generic((__force const void *)src, 56 dst, len, isum, errp, NULL); 57 if (unlikely(*errp)) 58 goto out_err; 59 60 return isum; 61 62 out_err: 63 *errp = -EFAULT; 64 memset(dst, 0, len); 65 66 return isum; 67 } 68 EXPORT_SYMBOL(csum_partial_copy_from_user); 69 70 /** 71 * csum_partial_copy_to_user - Copy and checksum to user space. 72 * @src: source address 73 * @dst: destination address (user space) 74 * @len: number of bytes to be copied. 75 * @isum: initial sum that is added into the result (32bit unfolded) 76 * @errp: set to -EFAULT for an bad destination address. 77 * 78 * Returns an 32bit unfolded checksum of the buffer. 79 * src and dst are best aligned to 64bits. 80 */ 81 __wsum 82 csum_partial_copy_to_user(const void *src, void __user *dst, 83 int len, __wsum isum, int *errp) 84 { 85 might_sleep(); 86 87 if (unlikely(!access_ok(VERIFY_WRITE, dst, len))) { 88 *errp = -EFAULT; 89 return 0; 90 } 91 92 if (unlikely((unsigned long)dst & 6)) { 93 while (((unsigned long)dst & 6) && len >= 2) { 94 __u16 val16 = *(__u16 *)src; 95 96 isum = (__force __wsum)add32_with_carry( 97 (__force unsigned)isum, val16); 98 *errp = __put_user(val16, (__u16 __user *)dst); 99 if (*errp) 100 return isum; 101 src += 2; 102 dst += 2; 103 len -= 2; 104 } 105 } 106 107 *errp = 0; 108 return csum_partial_copy_generic(src, (void __force *)dst, 109 len, isum, NULL, errp); 110 } 111 EXPORT_SYMBOL(csum_partial_copy_to_user); 112 113 /** 114 * csum_partial_copy_nocheck - Copy and checksum. 115 * @src: source address 116 * @dst: destination address 117 * @len: number of bytes to be copied. 118 * @sum: initial sum that is added into the result (32bit unfolded) 119 * 120 * Returns an 32bit unfolded checksum of the buffer. 121 */ 122 __wsum 123 csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum) 124 { 125 return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL); 126 } 127 EXPORT_SYMBOL(csum_partial_copy_nocheck); 128 129 __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 130 const struct in6_addr *daddr, 131 __u32 len, unsigned short proto, __wsum sum) 132 { 133 __u64 rest, sum64; 134 135 rest = (__force __u64)htonl(len) + (__force __u64)htons(proto) + 136 (__force __u64)sum; 137 138 asm(" addq (%[saddr]),%[sum]\n" 139 " adcq 8(%[saddr]),%[sum]\n" 140 " adcq (%[daddr]),%[sum]\n" 141 " adcq 8(%[daddr]),%[sum]\n" 142 " adcq $0,%[sum]\n" 143 144 : [sum] "=r" (sum64) 145 : "[sum]" (rest), [saddr] "r" (saddr), [daddr] "r" (daddr)); 146 147 return csum_fold( 148 (__force __wsum)add32_with_carry(sum64 & 0xffffffff, sum64>>32)); 149 } 150 EXPORT_SYMBOL(csum_ipv6_magic); 151