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 #include "kmap_types.h"
17
18 #include <linux/kernel.h>
19 #include <linux/mm.h>
20 #include <linux/pagemap.h>
21 #include <linux/highmem.h>
22 #include <asm/scatterlist.h>
23 #include "internal.h"
24 #include "scatterwalk.h"
25
26 enum km_type crypto_km_types[] = {
27 KM_USER0,
28 KM_USER1,
29 KM_SOFTIRQ0,
30 KM_SOFTIRQ1,
31 };
32
scatterwalk_whichbuf(struct scatter_walk * walk,unsigned int nbytes,void * scratch)33 void *scatterwalk_whichbuf(struct scatter_walk *walk, unsigned int nbytes, void *scratch)
34 {
35 if (nbytes <= walk->len_this_page &&
36 (((unsigned long)walk->data) & (PAGE_CACHE_SIZE - 1)) + nbytes <=
37 PAGE_CACHE_SIZE)
38 return walk->data;
39 else
40 return scratch;
41 }
42
memcpy_dir(void * buf,void * sgdata,size_t nbytes,int out)43 static void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
44 {
45 if (out)
46 memcpy(sgdata, buf, nbytes);
47 else
48 memcpy(buf, sgdata, nbytes);
49 }
50
scatterwalk_start(struct scatter_walk * walk,struct scatterlist * sg)51 void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg)
52 {
53 unsigned int rest_of_page;
54
55 walk->sg = sg;
56
57 walk->page = sg->page;
58 walk->len_this_segment = sg->length;
59
60 rest_of_page = PAGE_CACHE_SIZE - (sg->offset & (PAGE_CACHE_SIZE - 1));
61 walk->len_this_page = min(sg->length, rest_of_page);
62 walk->offset = sg->offset;
63 }
64
scatterwalk_map(struct scatter_walk * walk,int out)65 void scatterwalk_map(struct scatter_walk *walk, int out)
66 {
67 walk->data = crypto_kmap(walk->page, out) + walk->offset;
68 }
69
scatterwalk_pagedone(struct scatter_walk * walk,int out,unsigned int more)70 static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
71 unsigned int more)
72 {
73 /* walk->data may be pointing the first byte of the next page;
74 however, we know we transferred at least one byte. So,
75 walk->data - 1 will be a virtual address in the mapped page. */
76
77 if (out)
78 flush_dcache_page(walk->page);
79
80 if (more) {
81 walk->len_this_segment -= walk->len_this_page;
82
83 if (walk->len_this_segment) {
84 walk->page++;
85 walk->len_this_page = min(walk->len_this_segment,
86 (unsigned)PAGE_CACHE_SIZE);
87 walk->offset = 0;
88 }
89 else
90 scatterwalk_start(walk, sg_next(walk->sg));
91 }
92 }
93
scatterwalk_done(struct scatter_walk * walk,int out,int more)94 void scatterwalk_done(struct scatter_walk *walk, int out, int more)
95 {
96 crypto_kunmap(walk->data, out);
97 if (walk->len_this_page == 0 || !more)
98 scatterwalk_pagedone(walk, out, more);
99 }
100
101 /*
102 * Do not call this unless the total length of all of the fragments
103 * has been verified as multiple of the block size.
104 */
scatterwalk_copychunks(void * buf,struct scatter_walk * walk,size_t nbytes,int out)105 int scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
106 size_t nbytes, int out)
107 {
108 if (buf != walk->data) {
109 while (nbytes > walk->len_this_page) {
110 memcpy_dir(buf, walk->data, walk->len_this_page, out);
111 buf += walk->len_this_page;
112 nbytes -= walk->len_this_page;
113
114 crypto_kunmap(walk->data, out);
115 scatterwalk_pagedone(walk, out, 1);
116 scatterwalk_map(walk, out);
117 }
118
119 memcpy_dir(buf, walk->data, nbytes, out);
120 }
121
122 walk->offset += nbytes;
123 walk->len_this_page -= nbytes;
124 walk->len_this_segment -= nbytes;
125 return 0;
126 }
127