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 * @isum: 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
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