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 disable_kernel_vsx(); 91 pagefault_enable(); 92 preempt_enable(); 93 94 ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen); 95 return ret; 96 } 97 98 static int p8_aes_cbc_encrypt(struct blkcipher_desc *desc, 99 struct scatterlist *dst, 100 struct scatterlist *src, unsigned int nbytes) 101 { 102 int ret; 103 struct blkcipher_walk walk; 104 struct p8_aes_cbc_ctx *ctx = 105 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm)); 106 struct blkcipher_desc fallback_desc = { 107 .tfm = ctx->fallback, 108 .info = desc->info, 109 .flags = desc->flags 110 }; 111 112 if (in_interrupt()) { 113 ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src, 114 nbytes); 115 } else { 116 preempt_disable(); 117 pagefault_disable(); 118 enable_kernel_vsx(); 119 120 blkcipher_walk_init(&walk, dst, src, nbytes); 121 ret = blkcipher_walk_virt(desc, &walk); 122 while ((nbytes = walk.nbytes)) { 123 aes_p8_cbc_encrypt(walk.src.virt.addr, 124 walk.dst.virt.addr, 125 nbytes & AES_BLOCK_MASK, 126 &ctx->enc_key, walk.iv, 1); 127 nbytes &= AES_BLOCK_SIZE - 1; 128 ret = blkcipher_walk_done(desc, &walk, nbytes); 129 } 130 131 disable_kernel_vsx(); 132 pagefault_enable(); 133 preempt_enable(); 134 } 135 136 return ret; 137 } 138 139 static int p8_aes_cbc_decrypt(struct blkcipher_desc *desc, 140 struct scatterlist *dst, 141 struct scatterlist *src, unsigned int nbytes) 142 { 143 int ret; 144 struct blkcipher_walk walk; 145 struct p8_aes_cbc_ctx *ctx = 146 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm)); 147 struct blkcipher_desc fallback_desc = { 148 .tfm = ctx->fallback, 149 .info = desc->info, 150 .flags = desc->flags 151 }; 152 153 if (in_interrupt()) { 154 ret = crypto_blkcipher_decrypt(&fallback_desc, dst, src, 155 nbytes); 156 } else { 157 preempt_disable(); 158 pagefault_disable(); 159 enable_kernel_vsx(); 160 161 blkcipher_walk_init(&walk, dst, src, nbytes); 162 ret = blkcipher_walk_virt(desc, &walk); 163 while ((nbytes = walk.nbytes)) { 164 aes_p8_cbc_encrypt(walk.src.virt.addr, 165 walk.dst.virt.addr, 166 nbytes & AES_BLOCK_MASK, 167 &ctx->dec_key, walk.iv, 0); 168 nbytes &= AES_BLOCK_SIZE - 1; 169 ret = blkcipher_walk_done(desc, &walk, nbytes); 170 } 171 172 disable_kernel_vsx(); 173 pagefault_enable(); 174 preempt_enable(); 175 } 176 177 return ret; 178 } 179 180 181 struct crypto_alg p8_aes_cbc_alg = { 182 .cra_name = "cbc(aes)", 183 .cra_driver_name = "p8_aes_cbc", 184 .cra_module = THIS_MODULE, 185 .cra_priority = 1000, 186 .cra_type = &crypto_blkcipher_type, 187 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK, 188 .cra_alignmask = 0, 189 .cra_blocksize = AES_BLOCK_SIZE, 190 .cra_ctxsize = sizeof(struct p8_aes_cbc_ctx), 191 .cra_init = p8_aes_cbc_init, 192 .cra_exit = p8_aes_cbc_exit, 193 .cra_blkcipher = { 194 .ivsize = 0, 195 .min_keysize = AES_MIN_KEY_SIZE, 196 .max_keysize = AES_MAX_KEY_SIZE, 197 .setkey = p8_aes_cbc_setkey, 198 .encrypt = p8_aes_cbc_encrypt, 199 .decrypt = p8_aes_cbc_decrypt, 200 }, 201 }; 202