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 26 enum km_type crypto_km_types[] = { 27 KM_USER0, 28 KM_USER1, 29 KM_SOFTIRQ0, 30 KM_SOFTIRQ1, 31 }; 32 EXPORT_SYMBOL_GPL(crypto_km_types); 33 34 static 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 42 void 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 } 50 EXPORT_SYMBOL_GPL(scatterwalk_start); 51 52 void *scatterwalk_map(struct scatter_walk *walk, int out) 53 { 54 return crypto_kmap(scatterwalk_page(walk), out) + 55 offset_in_page(walk->offset); 56 } 57 EXPORT_SYMBOL_GPL(scatterwalk_map); 58 59 static 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 77 void 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 } 82 EXPORT_SYMBOL_GPL(scatterwalk_done); 83 84 void 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 } 109 EXPORT_SYMBOL_GPL(scatterwalk_copychunks); 110