Merge branch 'hotfixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris...
[linux-2.6] / arch / x86 / lib / csum-wrappers_64.c
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);