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 <asm/simd.h> 27 #include <asm/switch_to.h> 28 #include <crypto/aes.h> 29 #include <crypto/internal/simd.h> 30 #include <crypto/scatterwalk.h> 31 #include <crypto/skcipher.h> 32 33 #include "aesp8-ppc.h" 34 35 struct p8_aes_cbc_ctx { 36 struct crypto_sync_skcipher *fallback; 37 struct aes_key enc_key; 38 struct aes_key dec_key; 39 }; 40 41 static int p8_aes_cbc_init(struct crypto_tfm *tfm) 42 { 43 const char *alg = crypto_tfm_alg_name(tfm); 44 struct crypto_sync_skcipher *fallback; 45 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 46 47 fallback = crypto_alloc_sync_skcipher(alg, 0, 48 CRYPTO_ALG_NEED_FALLBACK); 49 50 if (IS_ERR(fallback)) { 51 printk(KERN_ERR 52 "Failed to allocate transformation for '%s': %ld\n", 53 alg, PTR_ERR(fallback)); 54 return PTR_ERR(fallback); 55 } 56 57 crypto_sync_skcipher_set_flags( 58 fallback, 59 crypto_skcipher_get_flags((struct crypto_skcipher *)tfm)); 60 ctx->fallback = fallback; 61 62 return 0; 63 } 64 65 static void p8_aes_cbc_exit(struct crypto_tfm *tfm) 66 { 67 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 68 69 if (ctx->fallback) { 70 crypto_free_sync_skcipher(ctx->fallback); 71 ctx->fallback = NULL; 72 } 73 } 74 75 static int p8_aes_cbc_setkey(struct crypto_tfm *tfm, const u8 *key, 76 unsigned int keylen) 77 { 78 int ret; 79 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm); 80 81 preempt_disable(); 82 pagefault_disable(); 83 enable_kernel_vsx(); 84 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key); 85 ret |= aes_p8_set_decrypt_key(key, keylen * 8, &ctx->dec_key); 86 disable_kernel_vsx(); 87 pagefault_enable(); 88 preempt_enable(); 89 90 ret |= crypto_sync_skcipher_setkey(ctx->fallback, key, keylen); 91 92 return ret ? -EINVAL : 0; 93 } 94 95 static int p8_aes_cbc_encrypt(struct blkcipher_desc *desc, 96 struct scatterlist *dst, 97 struct scatterlist *src, unsigned int nbytes) 98 { 99 int ret; 100 struct blkcipher_walk walk; 101 struct p8_aes_cbc_ctx *ctx = 102 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm)); 103 104 if (!crypto_simd_usable()) { 105 SYNC_SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback); 106 skcipher_request_set_sync_tfm(req, ctx->fallback); 107 skcipher_request_set_callback(req, desc->flags, NULL, NULL); 108 skcipher_request_set_crypt(req, src, dst, nbytes, desc->info); 109 ret = crypto_skcipher_encrypt(req); 110 skcipher_request_zero(req); 111 } else { 112 blkcipher_walk_init(&walk, dst, src, nbytes); 113 ret = blkcipher_walk_virt(desc, &walk); 114 while ((nbytes = walk.nbytes)) { 115 preempt_disable(); 116 pagefault_disable(); 117 enable_kernel_vsx(); 118 aes_p8_cbc_encrypt(walk.src.virt.addr, 119 walk.dst.virt.addr, 120 nbytes & AES_BLOCK_MASK, 121 &ctx->enc_key, walk.iv, 1); 122 disable_kernel_vsx(); 123 pagefault_enable(); 124 preempt_enable(); 125 126 nbytes &= AES_BLOCK_SIZE - 1; 127 ret = blkcipher_walk_done(desc, &walk, nbytes); 128 } 129 } 130 131 return ret; 132 } 133 134 static int p8_aes_cbc_decrypt(struct blkcipher_desc *desc, 135 struct scatterlist *dst, 136 struct scatterlist *src, unsigned int nbytes) 137 { 138 int ret; 139 struct blkcipher_walk walk; 140 struct p8_aes_cbc_ctx *ctx = 141 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm)); 142 143 if (!crypto_simd_usable()) { 144 SYNC_SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback); 145 skcipher_request_set_sync_tfm(req, ctx->fallback); 146 skcipher_request_set_callback(req, desc->flags, NULL, NULL); 147 skcipher_request_set_crypt(req, src, dst, nbytes, desc->info); 148 ret = crypto_skcipher_decrypt(req); 149 skcipher_request_zero(req); 150 } else { 151 blkcipher_walk_init(&walk, dst, src, nbytes); 152 ret = blkcipher_walk_virt(desc, &walk); 153 while ((nbytes = walk.nbytes)) { 154 preempt_disable(); 155 pagefault_disable(); 156 enable_kernel_vsx(); 157 aes_p8_cbc_encrypt(walk.src.virt.addr, 158 walk.dst.virt.addr, 159 nbytes & AES_BLOCK_MASK, 160 &ctx->dec_key, walk.iv, 0); 161 disable_kernel_vsx(); 162 pagefault_enable(); 163 preempt_enable(); 164 165 nbytes &= AES_BLOCK_SIZE - 1; 166 ret = blkcipher_walk_done(desc, &walk, nbytes); 167 } 168 } 169 170 return ret; 171 } 172 173 174 struct crypto_alg p8_aes_cbc_alg = { 175 .cra_name = "cbc(aes)", 176 .cra_driver_name = "p8_aes_cbc", 177 .cra_module = THIS_MODULE, 178 .cra_priority = 2000, 179 .cra_type = &crypto_blkcipher_type, 180 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK, 181 .cra_alignmask = 0, 182 .cra_blocksize = AES_BLOCK_SIZE, 183 .cra_ctxsize = sizeof(struct p8_aes_cbc_ctx), 184 .cra_init = p8_aes_cbc_init, 185 .cra_exit = p8_aes_cbc_exit, 186 .cra_blkcipher = { 187 .ivsize = AES_BLOCK_SIZE, 188 .min_keysize = AES_MIN_KEY_SIZE, 189 .max_keysize = AES_MAX_KEY_SIZE, 190 .setkey = p8_aes_cbc_setkey, 191 .encrypt = p8_aes_cbc_encrypt, 192 .decrypt = p8_aes_cbc_decrypt, 193 }, 194 }; 195