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 33 struct p8_aes_cbc_ctx { 34 struct crypto_blkcipher *fallback; 35 struct aes_key enc_key; 36 struct aes_key dec_key; 37 }; 38 39 static 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 = 51 crypto_alloc_blkcipher(alg, 0, CRYPTO_ALG_NEED_FALLBACK); 52 if (IS_ERR(fallback)) { 53 printk(KERN_ERR 54 "Failed to allocate transformation for '%s': %ld\n", 55 alg, PTR_ERR(fallback)); 56 return PTR_ERR(fallback); 57 } 58 printk(KERN_INFO "Using '%s' as fallback implementation.\n", 59 crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback)); 60 61 crypto_blkcipher_set_flags( 62 fallback, 63 crypto_blkcipher_get_flags((struct crypto_blkcipher *)tfm)); 64 ctx->fallback = fallback; 65 66 return 0; 67 } 68 69 static void p8_aes_cbc_exit(struct crypto_tfm *tfm) 70 { 71 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 72 73 if (ctx->fallback) { 74 crypto_free_blkcipher(ctx->fallback); 75 ctx->fallback = NULL; 76 } 77 } 78 79 static int p8_aes_cbc_setkey(struct crypto_tfm *tfm, const u8 *key, 80 unsigned int keylen) 81 { 82 int ret; 83 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 84 85 preempt_disable(); 86 pagefault_disable(); 87 enable_kernel_vsx(); 88 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key); 89 ret += aes_p8_set_decrypt_key(key, keylen * 8, &ctx->dec_key); 90 pagefault_enable(); 91 preempt_enable(); 92 93 ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen); 94 return ret; 95 } 96 97 static int p8_aes_cbc_encrypt(struct blkcipher_desc *desc, 98 struct scatterlist *dst, 99 struct scatterlist *src, unsigned int nbytes) 100 { 101 int ret; 102 struct blkcipher_walk walk; 103 struct p8_aes_cbc_ctx *ctx = 104 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm)); 105 struct blkcipher_desc fallback_desc = { 106 .tfm = ctx->fallback, 107 .info = desc->info, 108 .flags = desc->flags 109 }; 110 111 if (in_interrupt()) { 112 ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src, 113 nbytes); 114 } else { 115 preempt_disable(); 116 pagefault_disable(); 117 enable_kernel_vsx(); 118 119 blkcipher_walk_init(&walk, dst, src, nbytes); 120 ret = blkcipher_walk_virt(desc, &walk); 121 while ((nbytes = walk.nbytes)) { 122 aes_p8_cbc_encrypt(walk.src.virt.addr, 123 walk.dst.virt.addr, 124 nbytes & AES_BLOCK_MASK, 125 &ctx->enc_key, walk.iv, 1); 126 nbytes &= AES_BLOCK_SIZE - 1; 127 ret = blkcipher_walk_done(desc, &walk, nbytes); 128 } 129 130 pagefault_enable(); 131 preempt_enable(); 132 } 133 134 return ret; 135 } 136 137 static int p8_aes_cbc_decrypt(struct blkcipher_desc *desc, 138 struct scatterlist *dst, 139 struct scatterlist *src, unsigned int nbytes) 140 { 141 int ret; 142 struct blkcipher_walk walk; 143 struct p8_aes_cbc_ctx *ctx = 144 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm)); 145 struct blkcipher_desc fallback_desc = { 146 .tfm = ctx->fallback, 147 .info = desc->info, 148 .flags = desc->flags 149 }; 150 151 if (in_interrupt()) { 152 ret = crypto_blkcipher_decrypt(&fallback_desc, dst, src, 153 nbytes); 154 } else { 155 preempt_disable(); 156 pagefault_disable(); 157 enable_kernel_vsx(); 158 159 blkcipher_walk_init(&walk, dst, src, nbytes); 160 ret = blkcipher_walk_virt(desc, &walk); 161 while ((nbytes = walk.nbytes)) { 162 aes_p8_cbc_encrypt(walk.src.virt.addr, 163 walk.dst.virt.addr, 164 nbytes & AES_BLOCK_MASK, 165 &ctx->dec_key, walk.iv, 0); 166 nbytes &= AES_BLOCK_SIZE - 1; 167 ret = blkcipher_walk_done(desc, &walk, nbytes); 168 } 169 170 pagefault_enable(); 171 preempt_enable(); 172 } 173 174 return ret; 175 } 176 177 178 struct crypto_alg p8_aes_cbc_alg = { 179 .cra_name = "cbc(aes)", 180 .cra_driver_name = "p8_aes_cbc", 181 .cra_module = THIS_MODULE, 182 .cra_priority = 1000, 183 .cra_type = &crypto_blkcipher_type, 184 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK, 185 .cra_alignmask = 0, 186 .cra_blocksize = AES_BLOCK_SIZE, 187 .cra_ctxsize = sizeof(struct p8_aes_cbc_ctx), 188 .cra_init = p8_aes_cbc_init, 189 .cra_exit = p8_aes_cbc_exit, 190 .cra_blkcipher = { 191 .ivsize = 0, 192 .min_keysize = AES_MIN_KEY_SIZE, 193 .max_keysize = AES_MAX_KEY_SIZE, 194 .setkey = p8_aes_cbc_setkey, 195 .encrypt = p8_aes_cbc_encrypt, 196 .decrypt = p8_aes_cbc_decrypt, 197 }, 198 }; 199