Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 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/bug.h> |
| 21 | #include <asm/scatterlist.h> |
| 22 | #include "internal.h" |
| 23 | #include "scatterwalk.h" |
| 24 | |
| 25 | enum km_type crypto_km_types[] = { |
| 26 | KM_USER0, |
| 27 | KM_USER1, |
| 28 | KM_SOFTIRQ0, |
| 29 | KM_SOFTIRQ1, |
| 30 | }; |
| 31 | |
| 32 | static void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out) |
| 33 | { |
| 34 | if (out) |
| 35 | memcpy(sgdata, buf, nbytes); |
| 36 | else |
| 37 | memcpy(buf, sgdata, nbytes); |
| 38 | } |
| 39 | |
| 40 | void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg) |
| 41 | { |
| 42 | unsigned int rest_of_page; |
| 43 | |
| 44 | walk->sg = sg; |
| 45 | |
| 46 | walk->page = sg->page; |
| 47 | walk->len_this_segment = sg->length; |
| 48 | |
| 49 | BUG_ON(!sg->length); |
| 50 | |
| 51 | rest_of_page = PAGE_CACHE_SIZE - (sg->offset & (PAGE_CACHE_SIZE - 1)); |
| 52 | walk->len_this_page = min(sg->length, rest_of_page); |
| 53 | walk->offset = sg->offset; |
| 54 | } |
| 55 | |
| 56 | void scatterwalk_map(struct scatter_walk *walk, int out) |
| 57 | { |
| 58 | walk->data = crypto_kmap(walk->page, out) + walk->offset; |
| 59 | } |
| 60 | |
| 61 | static inline void scatterwalk_unmap(struct scatter_walk *walk, int out) |
| 62 | { |
| 63 | /* walk->data may be pointing the first byte of the next page; |
| 64 | however, we know we transfered at least one byte. So, |
| 65 | walk->data - 1 will be a virtual address in the mapped page. */ |
| 66 | crypto_kunmap(walk->data - 1, out); |
| 67 | } |
| 68 | |
| 69 | static void scatterwalk_pagedone(struct scatter_walk *walk, int out, |
| 70 | unsigned int more) |
| 71 | { |
| 72 | if (out) |
| 73 | flush_dcache_page(walk->page); |
| 74 | |
| 75 | if (more) { |
| 76 | walk->len_this_segment -= walk->len_this_page; |
| 77 | |
| 78 | if (walk->len_this_segment) { |
| 79 | walk->page++; |
| 80 | walk->len_this_page = min(walk->len_this_segment, |
| 81 | (unsigned)PAGE_CACHE_SIZE); |
| 82 | walk->offset = 0; |
| 83 | } |
| 84 | else |
| 85 | scatterwalk_start(walk, sg_next(walk->sg)); |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | void scatterwalk_done(struct scatter_walk *walk, int out, int more) |
| 90 | { |
| 91 | scatterwalk_unmap(walk, out); |
| 92 | if (walk->len_this_page == 0 || !more) |
| 93 | scatterwalk_pagedone(walk, out, more); |
| 94 | } |
| 95 | |
| 96 | /* |
| 97 | * Do not call this unless the total length of all of the fragments |
| 98 | * has been verified as multiple of the block size. |
| 99 | */ |
| 100 | int scatterwalk_copychunks(void *buf, struct scatter_walk *walk, |
| 101 | size_t nbytes, int out) |
| 102 | { |
| 103 | do { |
| 104 | memcpy_dir(buf, walk->data, walk->len_this_page, out); |
| 105 | buf += walk->len_this_page; |
| 106 | nbytes -= walk->len_this_page; |
| 107 | |
| 108 | scatterwalk_unmap(walk, out); |
| 109 | scatterwalk_pagedone(walk, out, 1); |
| 110 | scatterwalk_map(walk, out); |
| 111 | } while (nbytes > walk->len_this_page); |
| 112 | |
| 113 | memcpy_dir(buf, walk->data, nbytes, out); |
| 114 | return nbytes; |
| 115 | } |