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#include <asm/smap.h>
10
11/**
12 * csum_partial_copy_from_user - Copy and checksum from user space.
13 * @src: source address (user space)
14 * @dst: destination address
15 * @len: number of bytes to be copied.
16 * @isum: initial sum that is added into the result (32bit unfolded)
17 * @errp: set to -EFAULT for an bad source address.
18 *
19 * Returns an 32bit unfolded checksum of the buffer.
20 * src and dst are best aligned to 64bits.
21 */
22__wsum
23csum_partial_copy_from_user(const void __user *src, void *dst,
24			    int len, __wsum isum, int *errp)
25{
26	might_sleep();
27	*errp = 0;
28
29	if (!likely(access_ok(VERIFY_READ, src, len)))
30		goto out_err;
31
32	/*
33	 * Why 6, not 7? To handle odd addresses aligned we
34	 * would need to do considerable complications to fix the
35	 * checksum which is defined as an 16bit accumulator. The
36	 * fix alignment code is primarily for performance
37	 * compatibility with 32bit and that will handle odd
38	 * addresses slowly too.
39	 */
40	if (unlikely((unsigned long)src & 6)) {
41		while (((unsigned long)src & 6) && len >= 2) {
42			__u16 val16;
43
44			if (__get_user(val16, (const __u16 __user *)src))
45				goto out_err;
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	stac();
56	isum = csum_partial_copy_generic((__force const void *)src,
57				dst, len, isum, errp, NULL);
58	clac();
59	if (unlikely(*errp))
60		goto out_err;
61
62	return isum;
63
64out_err:
65	*errp = -EFAULT;
66	memset(dst, 0, len);
67
68	return isum;
69}
70EXPORT_SYMBOL(csum_partial_copy_from_user);
71
72/**
73 * csum_partial_copy_to_user - Copy and checksum to user space.
74 * @src: source address
75 * @dst: destination address (user space)
76 * @len: number of bytes to be copied.
77 * @isum: initial sum that is added into the result (32bit unfolded)
78 * @errp: set to -EFAULT for an bad destination address.
79 *
80 * Returns an 32bit unfolded checksum of the buffer.
81 * src and dst are best aligned to 64bits.
82 */
83__wsum
84csum_partial_copy_to_user(const void *src, void __user *dst,
85			  int len, __wsum isum, int *errp)
86{
87	__wsum ret;
88
89	might_sleep();
90
91	if (unlikely(!access_ok(VERIFY_WRITE, dst, len))) {
92		*errp = -EFAULT;
93		return 0;
94	}
95
96	if (unlikely((unsigned long)dst & 6)) {
97		while (((unsigned long)dst & 6) && len >= 2) {
98			__u16 val16 = *(__u16 *)src;
99
100			isum = (__force __wsum)add32_with_carry(
101					(__force unsigned)isum, val16);
102			*errp = __put_user(val16, (__u16 __user *)dst);
103			if (*errp)
104				return isum;
105			src += 2;
106			dst += 2;
107			len -= 2;
108		}
109	}
110
111	*errp = 0;
112	stac();
113	ret = csum_partial_copy_generic(src, (void __force *)dst,
114					len, isum, NULL, errp);
115	clac();
116	return ret;
117}
118EXPORT_SYMBOL(csum_partial_copy_to_user);
119
120/**
121 * csum_partial_copy_nocheck - Copy and checksum.
122 * @src: source address
123 * @dst: destination address
124 * @len: number of bytes to be copied.
125 * @sum: initial sum that is added into the result (32bit unfolded)
126 *
127 * Returns an 32bit unfolded checksum of the buffer.
128 */
129__wsum
130csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
131{
132	return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
133}
134EXPORT_SYMBOL(csum_partial_copy_nocheck);
135
136__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
137			const struct in6_addr *daddr,
138			__u32 len, unsigned short proto, __wsum sum)
139{
140	__u64 rest, sum64;
141
142	rest = (__force __u64)htonl(len) + (__force __u64)htons(proto) +
143		(__force __u64)sum;
144
145	asm("	addq (%[saddr]),%[sum]\n"
146	    "	adcq 8(%[saddr]),%[sum]\n"
147	    "	adcq (%[daddr]),%[sum]\n"
148	    "	adcq 8(%[daddr]),%[sum]\n"
149	    "	adcq $0,%[sum]\n"
150
151	    : [sum] "=r" (sum64)
152	    : "[sum]" (rest), [saddr] "r" (saddr), [daddr] "r" (daddr));
153
154	return csum_fold(
155	       (__force __wsum)add32_with_carry(sum64 & 0xffffffff, sum64>>32));
156}
157EXPORT_SYMBOL(csum_ipv6_magic);
158