[SPARC64]: Fix %tstate ASI handling in start_thread{,32}()
[linux-2.6.git] / crypto / scatterwalk.c
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 <linux/kernel.h>
17 #include <linux/mm.h>
18 #include <linux/pagemap.h>
19 #include <linux/highmem.h>
20 #include <asm/scatterlist.h>
21 #include "internal.h"
22 #include "scatterwalk.h"
23
24 enum km_type crypto_km_types[] = {
25         KM_USER0,
26         KM_USER1,
27         KM_SOFTIRQ0,
28         KM_SOFTIRQ1,
29 };
30
31 static void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
32 {
33         if (out)
34                 memcpy(sgdata, buf, nbytes);
35         else
36                 memcpy(buf, sgdata, nbytes);
37 }
38
39 void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg)
40 {
41         unsigned int rest_of_page;
42
43         walk->sg = sg;
44
45         walk->page = sg->page;
46         walk->len_this_segment = sg->length;
47
48         BUG_ON(!sg->length);
49
50         rest_of_page = PAGE_CACHE_SIZE - (sg->offset & (PAGE_CACHE_SIZE - 1));
51         walk->len_this_page = min(sg->length, rest_of_page);
52         walk->offset = sg->offset;
53 }
54
55 void scatterwalk_map(struct scatter_walk *walk, int out)
56 {
57         walk->data = crypto_kmap(walk->page, out) + walk->offset;
58 }
59
60 static inline void scatterwalk_unmap(struct scatter_walk *walk, int out)
61 {
62         /* walk->data may be pointing the first byte of the next page;
63            however, we know we transfered at least one byte.  So,
64            walk->data - 1 will be a virtual address in the mapped page. */
65         crypto_kunmap(walk->data - 1, out);
66 }
67
68 static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
69                                  unsigned int more)
70 {
71         if (out)
72                 flush_dcache_page(walk->page);
73
74         if (more) {
75                 walk->len_this_segment -= walk->len_this_page;
76
77                 if (walk->len_this_segment) {
78                         walk->page++;
79                         walk->len_this_page = min(walk->len_this_segment,
80                                                   (unsigned)PAGE_CACHE_SIZE);
81                         walk->offset = 0;
82                 }
83                 else
84                         scatterwalk_start(walk, sg_next(walk->sg));
85         }
86 }
87
88 void scatterwalk_done(struct scatter_walk *walk, int out, int more)
89 {
90         scatterwalk_unmap(walk, out);
91         if (walk->len_this_page == 0 || !more)
92                 scatterwalk_pagedone(walk, out, more);
93 }
94
95 /*
96  * Do not call this unless the total length of all of the fragments
97  * has been verified as multiple of the block size.
98  */
99 int scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
100                            size_t nbytes, int out)
101 {
102         while (nbytes > walk->len_this_page) {
103                 memcpy_dir(buf, walk->data, walk->len_this_page, out);
104                 buf += walk->len_this_page;
105                 nbytes -= walk->len_this_page;
106
107                 scatterwalk_unmap(walk, out);
108                 scatterwalk_pagedone(walk, out, 1);
109                 scatterwalk_map(walk, out);
110         }
111
112         memcpy_dir(buf, walk->data, nbytes, out);
113         return nbytes;
114 }