1/** 2 * AES CBC routines supporting VMX instructions on the Power 8 3 * 4 * Copyright (C) 2015 International Business Machines Inc. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; version 2 only. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 18 * 19 * Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com> 20 */ 21 22#include <linux/types.h> 23#include <linux/err.h> 24#include <linux/crypto.h> 25#include <linux/delay.h> 26#include <linux/hardirq.h> 27#include <asm/switch_to.h> 28#include <crypto/aes.h> 29#include <crypto/scatterwalk.h> 30 31#include "aesp8-ppc.h" 32 33struct p8_aes_cbc_ctx { 34 struct crypto_blkcipher *fallback; 35 struct aes_key enc_key; 36 struct aes_key dec_key; 37}; 38 39static int p8_aes_cbc_init(struct crypto_tfm *tfm) 40{ 41 const char *alg; 42 struct crypto_blkcipher *fallback; 43 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 44 45 if (!(alg = crypto_tfm_alg_name(tfm))) { 46 printk(KERN_ERR "Failed to get algorithm name.\n"); 47 return -ENOENT; 48 } 49 50 fallback = crypto_alloc_blkcipher(alg, 0 ,CRYPTO_ALG_NEED_FALLBACK); 51 if (IS_ERR(fallback)) { 52 printk(KERN_ERR "Failed to allocate transformation for '%s': %ld\n", 53 alg, PTR_ERR(fallback)); 54 return PTR_ERR(fallback); 55 } 56 printk(KERN_INFO "Using '%s' as fallback implementation.\n", 57 crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback)); 58 59 crypto_blkcipher_set_flags(fallback, 60 crypto_blkcipher_get_flags((struct crypto_blkcipher *) tfm)); 61 ctx->fallback = fallback; 62 63 return 0; 64} 65 66static void p8_aes_cbc_exit(struct crypto_tfm *tfm) 67{ 68 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 69 70 if (ctx->fallback) { 71 crypto_free_blkcipher(ctx->fallback); 72 ctx->fallback = NULL; 73 } 74} 75 76static int p8_aes_cbc_setkey(struct crypto_tfm *tfm, const u8 *key, 77 unsigned int keylen) 78{ 79 int ret; 80 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 81 82 pagefault_disable(); 83 enable_kernel_altivec(); 84 enable_kernel_vsx(); 85 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key); 86 ret += aes_p8_set_decrypt_key(key, keylen * 8, &ctx->dec_key); 87 pagefault_enable(); 88 89 ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen); 90 return ret; 91} 92 93static int p8_aes_cbc_encrypt(struct blkcipher_desc *desc, 94 struct scatterlist *dst, struct scatterlist *src, 95 unsigned int nbytes) 96{ 97 int ret; 98 struct blkcipher_walk walk; 99 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx( 100 crypto_blkcipher_tfm(desc->tfm)); 101 struct blkcipher_desc fallback_desc = { 102 .tfm = ctx->fallback, 103 .info = desc->info, 104 .flags = desc->flags 105 }; 106 107 if (in_interrupt()) { 108 ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src, nbytes); 109 } else { 110 pagefault_disable(); 111 enable_kernel_altivec(); 112 enable_kernel_vsx(); 113 114 blkcipher_walk_init(&walk, dst, src, nbytes); 115 ret = blkcipher_walk_virt(desc, &walk); 116 while ((nbytes = walk.nbytes)) { 117 aes_p8_cbc_encrypt(walk.src.virt.addr, walk.dst.virt.addr, 118 nbytes & AES_BLOCK_MASK, &ctx->enc_key, walk.iv, 1); 119 nbytes &= AES_BLOCK_SIZE - 1; 120 ret = blkcipher_walk_done(desc, &walk, nbytes); 121 } 122 123 pagefault_enable(); 124 } 125 126 return ret; 127} 128 129static int p8_aes_cbc_decrypt(struct blkcipher_desc *desc, 130 struct scatterlist *dst, struct scatterlist *src, 131 unsigned int nbytes) 132{ 133 int ret; 134 struct blkcipher_walk walk; 135 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx( 136 crypto_blkcipher_tfm(desc->tfm)); 137 struct blkcipher_desc fallback_desc = { 138 .tfm = ctx->fallback, 139 .info = desc->info, 140 .flags = desc->flags 141 }; 142 143 if (in_interrupt()) { 144 ret = crypto_blkcipher_decrypt(&fallback_desc, dst, src, nbytes); 145 } else { 146 pagefault_disable(); 147 enable_kernel_altivec(); 148 enable_kernel_vsx(); 149 150 blkcipher_walk_init(&walk, dst, src, nbytes); 151 ret = blkcipher_walk_virt(desc, &walk); 152 while ((nbytes = walk.nbytes)) { 153 aes_p8_cbc_encrypt(walk.src.virt.addr, walk.dst.virt.addr, 154 nbytes & AES_BLOCK_MASK, &ctx->dec_key, walk.iv, 0); 155 nbytes &= AES_BLOCK_SIZE - 1; 156 ret = blkcipher_walk_done(desc, &walk, nbytes); 157 } 158 159 pagefault_enable(); 160 } 161 162 return ret; 163} 164 165 166struct crypto_alg p8_aes_cbc_alg = { 167 .cra_name = "cbc(aes)", 168 .cra_driver_name = "p8_aes_cbc", 169 .cra_module = THIS_MODULE, 170 .cra_priority = 1000, 171 .cra_type = &crypto_blkcipher_type, 172 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK, 173 .cra_alignmask = 0, 174 .cra_blocksize = AES_BLOCK_SIZE, 175 .cra_ctxsize = sizeof(struct p8_aes_cbc_ctx), 176 .cra_init = p8_aes_cbc_init, 177 .cra_exit = p8_aes_cbc_exit, 178 .cra_blkcipher = { 179 .ivsize = 0, 180 .min_keysize = AES_MIN_KEY_SIZE, 181 .max_keysize = AES_MAX_KEY_SIZE, 182 .setkey = p8_aes_cbc_setkey, 183 .encrypt = p8_aes_cbc_encrypt, 184 .decrypt = p8_aes_cbc_decrypt, 185 }, 186}; 187 188