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/module.h>
19#include <linux/pagemap.h>
20#include <linux/highmem.h>
21#include <linux/scatterlist.h>
22
23#include "internal.h"
24#include "scatterwalk.h"
25
26enum km_type crypto_km_types[] = {
27	KM_USER0,
28	KM_USER1,
29	KM_SOFTIRQ0,
30	KM_SOFTIRQ1,
31};
32EXPORT_SYMBOL_GPL(crypto_km_types);
33
34static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
35{
36	void *src = out ? buf : sgdata;
37	void *dst = out ? sgdata : buf;
38
39	memcpy(dst, src, nbytes);
40}
41
42void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg)
43{
44	walk->sg = sg;
45
46	BUG_ON(!sg->length);
47
48	walk->offset = sg->offset;
49}
50EXPORT_SYMBOL_GPL(scatterwalk_start);
51
52void *scatterwalk_map(struct scatter_walk *walk, int out)
53{
54	return crypto_kmap(scatterwalk_page(walk), out) +
55	       offset_in_page(walk->offset);
56}
57EXPORT_SYMBOL_GPL(scatterwalk_map);
58
59static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
60				 unsigned int more)
61{
62	if (out) {
63		struct page *page;
64
65		page = walk->sg->page + ((walk->offset - 1) >> PAGE_SHIFT);
66		flush_dcache_page(page);
67	}
68
69	if (more) {
70		walk->offset += PAGE_SIZE - 1;
71		walk->offset &= PAGE_MASK;
72		if (walk->offset >= walk->sg->offset + walk->sg->length)
73			scatterwalk_start(walk, sg_next(walk->sg));
74	}
75}
76
77void scatterwalk_done(struct scatter_walk *walk, int out, int more)
78{
79	if (!offset_in_page(walk->offset) || !more)
80		scatterwalk_pagedone(walk, out, more);
81}
82EXPORT_SYMBOL_GPL(scatterwalk_done);
83
84void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
85			    size_t nbytes, int out)
86{
87	for (;;) {
88		unsigned int len_this_page = scatterwalk_pagelen(walk);
89		u8 *vaddr;
90
91		if (len_this_page > nbytes)
92			len_this_page = nbytes;
93
94		vaddr = scatterwalk_map(walk, out);
95		memcpy_dir(buf, vaddr, len_this_page, out);
96		scatterwalk_unmap(vaddr, out);
97
98		scatterwalk_advance(walk, len_this_page);
99
100		if (nbytes == len_this_page)
101			break;
102
103		buf += len_this_page;
104		nbytes -= len_this_page;
105
106		scatterwalk_pagedone(walk, out, 1);
107	}
108}
109EXPORT_SYMBOL_GPL(scatterwalk_copychunks);
110