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1/*
2 * Cryptographic API.
3 *
4 * Cipher operations.
5 *
6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
7 * 2002 Adam J. Richter <adam@yggdrasil.com>
8 * 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the Free
12 * Software Foundation; either version 2 of the License, or (at your option)
13 * any later version.
14 *
15 */
16
17#include <crypto/scatterwalk.h>
18#include <linux/kernel.h>
19#include <linux/mm.h>
20#include <linux/module.h>
21#include <linux/pagemap.h>
22#include <linux/highmem.h>
23#include <linux/scatterlist.h>
24
25static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
26{
27 void *src = out ? buf : sgdata;
28 void *dst = out ? sgdata : buf;
29
30 memcpy(dst, src, nbytes);
31}
32
33void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg)
34{
35 walk->sg = sg;
36
37 BUG_ON(!sg->length);
38
39 walk->offset = sg->offset;
40}
41EXPORT_SYMBOL_GPL(scatterwalk_start);
42
43void *scatterwalk_map(struct scatter_walk *walk)
44{
45 return kmap_atomic(scatterwalk_page(walk)) +
46 offset_in_page(walk->offset);
47}
48EXPORT_SYMBOL_GPL(scatterwalk_map);
49
50static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
51 unsigned int more)
52{
53 if (out) {
54 struct page *page;
55
56 page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
57 /* Test ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE first as
58 * PageSlab cannot be optimised away per se due to
59 * use of volatile pointer.
60 */
61 if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE && !PageSlab(page))
62 flush_dcache_page(page);
63 }
64
65 if (more) {
66 walk->offset += PAGE_SIZE - 1;
67 walk->offset &= PAGE_MASK;
68 if (walk->offset >= walk->sg->offset + walk->sg->length)
69 scatterwalk_start(walk, sg_next(walk->sg));
70 }
71}
72
73void scatterwalk_done(struct scatter_walk *walk, int out, int more)
74{
75 if (!(scatterwalk_pagelen(walk) & (PAGE_SIZE - 1)) || !more)
76 scatterwalk_pagedone(walk, out, more);
77}
78EXPORT_SYMBOL_GPL(scatterwalk_done);
79
80void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
81 size_t nbytes, int out)
82{
83 for (;;) {
84 unsigned int len_this_page = scatterwalk_pagelen(walk);
85 u8 *vaddr;
86
87 if (len_this_page > nbytes)
88 len_this_page = nbytes;
89
90 vaddr = scatterwalk_map(walk);
91 memcpy_dir(buf, vaddr, len_this_page, out);
92 scatterwalk_unmap(vaddr);
93
94 scatterwalk_advance(walk, len_this_page);
95
96 if (nbytes == len_this_page)
97 break;
98
99 buf += len_this_page;
100 nbytes -= len_this_page;
101
102 scatterwalk_pagedone(walk, out, 1);
103 }
104}
105EXPORT_SYMBOL_GPL(scatterwalk_copychunks);
106
107void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
108 unsigned int start, unsigned int nbytes, int out)
109{
110 struct scatter_walk walk;
111 struct scatterlist tmp[2];
112
113 if (!nbytes)
114 return;
115
116 sg = scatterwalk_ffwd(tmp, sg, start);
117
118 if (sg_page(sg) == virt_to_page(buf) &&
119 sg->offset == offset_in_page(buf))
120 return;
121
122 scatterwalk_start(&walk, sg);
123 scatterwalk_copychunks(buf, &walk, nbytes, out);
124 scatterwalk_done(&walk, out, 0);
125}
126EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy);
127
128int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes)
129{
130 int offset = 0, n = 0;
131
132 /* num_bytes is too small */
133 if (num_bytes < sg->length)
134 return -1;
135
136 do {
137 offset += sg->length;
138 n++;
139 sg = sg_next(sg);
140
141 /* num_bytes is too large */
142 if (unlikely(!sg && (num_bytes < offset)))
143 return -1;
144 } while (sg && (num_bytes > offset));
145
146 return n;
147}
148EXPORT_SYMBOL_GPL(scatterwalk_bytes_sglen);
149
150struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
151 struct scatterlist *src,
152 unsigned int len)
153{
154 for (;;) {
155 if (!len)
156 return src;
157
158 if (src->length > len)
159 break;
160
161 len -= src->length;
162 src = sg_next(src);
163 }
164
165 sg_init_table(dst, 2);
166 sg_set_page(dst, sg_page(src), src->length - len, src->offset + len);
167 scatterwalk_crypto_chain(dst, sg_next(src), 0, 2);
168
169 return dst;
170}
171EXPORT_SYMBOL_GPL(scatterwalk_ffwd);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Cryptographic API.
4 *
5 * Cipher operations.
6 *
7 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
8 * 2002 Adam J. Richter <adam@yggdrasil.com>
9 * 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
10 */
11
12#include <crypto/scatterwalk.h>
13#include <linux/kernel.h>
14#include <linux/mm.h>
15#include <linux/module.h>
16#include <linux/scatterlist.h>
17
18static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
19{
20 void *src = out ? buf : sgdata;
21 void *dst = out ? sgdata : buf;
22
23 memcpy(dst, src, nbytes);
24}
25
26void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
27 size_t nbytes, int out)
28{
29 for (;;) {
30 unsigned int len_this_page = scatterwalk_pagelen(walk);
31 u8 *vaddr;
32
33 if (len_this_page > nbytes)
34 len_this_page = nbytes;
35
36 if (out != 2) {
37 vaddr = scatterwalk_map(walk);
38 memcpy_dir(buf, vaddr, len_this_page, out);
39 scatterwalk_unmap(vaddr);
40 }
41
42 scatterwalk_advance(walk, len_this_page);
43
44 if (nbytes == len_this_page)
45 break;
46
47 buf += len_this_page;
48 nbytes -= len_this_page;
49
50 scatterwalk_pagedone(walk, out & 1, 1);
51 }
52}
53EXPORT_SYMBOL_GPL(scatterwalk_copychunks);
54
55void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
56 unsigned int start, unsigned int nbytes, int out)
57{
58 struct scatter_walk walk;
59 struct scatterlist tmp[2];
60
61 if (!nbytes)
62 return;
63
64 sg = scatterwalk_ffwd(tmp, sg, start);
65
66 scatterwalk_start(&walk, sg);
67 scatterwalk_copychunks(buf, &walk, nbytes, out);
68 scatterwalk_done(&walk, out, 0);
69}
70EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy);
71
72struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
73 struct scatterlist *src,
74 unsigned int len)
75{
76 for (;;) {
77 if (!len)
78 return src;
79
80 if (src->length > len)
81 break;
82
83 len -= src->length;
84 src = sg_next(src);
85 }
86
87 sg_init_table(dst, 2);
88 sg_set_page(dst, sg_page(src), src->length - len, src->offset + len);
89 scatterwalk_crypto_chain(dst, sg_next(src), 2);
90
91 return dst;
92}
93EXPORT_SYMBOL_GPL(scatterwalk_ffwd);