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