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 | * |
18 | * Returns an 32bit unfolded checksum of the buffer. |
19 | * src and dst are best aligned to 64bits. |
20 | */ |
21 | __wsum |
22 | csum_and_copy_from_user(const void __user *src, void *dst, int len) |
23 | { |
24 | __wsum sum; |
25 | |
26 | might_sleep(); |
27 | if (!user_access_begin(src, len)) |
28 | return 0; |
29 | sum = csum_partial_copy_generic(src: (__force const void *)src, dst, len); |
30 | user_access_end(); |
31 | return sum; |
32 | } |
33 | |
34 | /** |
35 | * csum_and_copy_to_user - Copy and checksum to user space. |
36 | * @src: source address |
37 | * @dst: destination address (user space) |
38 | * @len: number of bytes to be copied. |
39 | * |
40 | * Returns an 32bit unfolded checksum of the buffer. |
41 | * src and dst are best aligned to 64bits. |
42 | */ |
43 | __wsum |
44 | csum_and_copy_to_user(const void *src, void __user *dst, int len) |
45 | { |
46 | __wsum sum; |
47 | |
48 | might_sleep(); |
49 | if (!user_access_begin(dst, len)) |
50 | return 0; |
51 | sum = csum_partial_copy_generic(src, dst: (void __force *)dst, len); |
52 | user_access_end(); |
53 | return sum; |
54 | } |
55 | |
56 | /** |
57 | * csum_partial_copy_nocheck - Copy and checksum. |
58 | * @src: source address |
59 | * @dst: destination address |
60 | * @len: number of bytes to be copied. |
61 | * |
62 | * Returns an 32bit unfolded checksum of the buffer. |
63 | */ |
64 | __wsum |
65 | csum_partial_copy_nocheck(const void *src, void *dst, int len) |
66 | { |
67 | return csum_partial_copy_generic(src, dst, len); |
68 | } |
69 | EXPORT_SYMBOL(csum_partial_copy_nocheck); |
70 | |
71 | __sum16 csum_ipv6_magic(const struct in6_addr *saddr, |
72 | const struct in6_addr *daddr, |
73 | __u32 len, __u8 proto, __wsum sum) |
74 | { |
75 | __u64 rest, sum64; |
76 | |
77 | rest = (__force __u64)htonl(len) + (__force __u64)htons(proto) + |
78 | (__force __u64)sum; |
79 | |
80 | asm(" addq (%[saddr]),%[sum]\n" |
81 | " adcq 8(%[saddr]),%[sum]\n" |
82 | " adcq (%[daddr]),%[sum]\n" |
83 | " adcq 8(%[daddr]),%[sum]\n" |
84 | " adcq $0,%[sum]\n" |
85 | |
86 | : [sum] "=r" (sum64) |
87 | : "[sum]" (rest), [saddr] "r" (saddr), [daddr] "r" (daddr)); |
88 | |
89 | return csum_fold( |
90 | sum: (__force __wsum)add32_with_carry(a: sum64 & 0xffffffff, b: sum64>>32)); |
91 | } |
92 | EXPORT_SYMBOL(csum_ipv6_magic); |
93 | |