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
csum_and_copy_from_user(const void __user * src,void * dst,int len)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
36 /**
37 * csum_and_copy_to_user - Copy and checksum to user space.
38 * @src: source address
39 * @dst: destination address (user space)
40 * @len: number of bytes to be copied.
41 * @isum: initial sum that is added into the result (32bit unfolded)
42 * @errp: set to -EFAULT for an bad destination address.
43 *
44 * Returns an 32bit unfolded checksum of the buffer.
45 * src and dst are best aligned to 64bits.
46 */
47 __wsum
csum_and_copy_to_user(const void * src,void __user * dst,int len)48 csum_and_copy_to_user(const void *src, void __user *dst, int len)
49 {
50 __wsum sum;
51
52 might_sleep();
53 if (!user_access_begin(dst, len))
54 return 0;
55 sum = csum_partial_copy_generic(src, (void __force *)dst, len);
56 user_access_end();
57 return sum;
58 }
59
60 /**
61 * csum_partial_copy_nocheck - Copy and checksum.
62 * @src: source address
63 * @dst: destination address
64 * @len: number of bytes to be copied.
65 * @sum: initial sum that is added into the result (32bit unfolded)
66 *
67 * Returns an 32bit unfolded checksum of the buffer.
68 */
69 __wsum
csum_partial_copy_nocheck(const void * src,void * dst,int len)70 csum_partial_copy_nocheck(const void *src, void *dst, int len)
71 {
72 return csum_partial_copy_generic(src, dst, len);
73 }
74 EXPORT_SYMBOL(csum_partial_copy_nocheck);
75
csum_ipv6_magic(const struct in6_addr * saddr,const struct in6_addr * daddr,__u32 len,__u8 proto,__wsum sum)76 __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
77 const struct in6_addr *daddr,
78 __u32 len, __u8 proto, __wsum sum)
79 {
80 __u64 rest, sum64;
81
82 rest = (__force __u64)htonl(len) + (__force __u64)htons(proto) +
83 (__force __u64)sum;
84
85 asm(" addq (%[saddr]),%[sum]\n"
86 " adcq 8(%[saddr]),%[sum]\n"
87 " adcq (%[daddr]),%[sum]\n"
88 " adcq 8(%[daddr]),%[sum]\n"
89 " adcq $0,%[sum]\n"
90
91 : [sum] "=r" (sum64)
92 : "[sum]" (rest), [saddr] "r" (saddr), [daddr] "r" (daddr));
93
94 return csum_fold(
95 (__force __wsum)add32_with_carry(sum64 & 0xffffffff, sum64>>32));
96 }
97 EXPORT_SYMBOL(csum_ipv6_magic);
98