1 /** 2 * AES CTR 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 "aesp8-ppc.h" 31 32 struct p8_aes_ctr_ctx { 33 struct crypto_blkcipher *fallback; 34 struct aes_key enc_key; 35 }; 36 37 static int p8_aes_ctr_init(struct crypto_tfm *tfm) 38 { 39 const char *alg; 40 struct crypto_blkcipher *fallback; 41 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); 42 43 if (!(alg = crypto_tfm_alg_name(tfm))) { 44 printk(KERN_ERR "Failed to get algorithm name.\n"); 45 return -ENOENT; 46 } 47 48 fallback = 49 crypto_alloc_blkcipher(alg, 0, CRYPTO_ALG_NEED_FALLBACK); 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 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( 60 fallback, 61 crypto_blkcipher_get_flags((struct crypto_blkcipher *)tfm)); 62 ctx->fallback = fallback; 63 64 return 0; 65 } 66 67 static void p8_aes_ctr_exit(struct crypto_tfm *tfm) 68 { 69 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); 70 71 if (ctx->fallback) { 72 crypto_free_blkcipher(ctx->fallback); 73 ctx->fallback = NULL; 74 } 75 } 76 77 static int p8_aes_ctr_setkey(struct crypto_tfm *tfm, const u8 *key, 78 unsigned int keylen) 79 { 80 int ret; 81 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); 82 83 pagefault_disable(); 84 enable_kernel_vsx(); 85 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key); 86 disable_kernel_vsx(); 87 pagefault_enable(); 88 89 ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen); 90 return ret; 91 } 92 93 static void p8_aes_ctr_final(struct p8_aes_ctr_ctx *ctx, 94 struct blkcipher_walk *walk) 95 { 96 u8 *ctrblk = walk->iv; 97 u8 keystream[AES_BLOCK_SIZE]; 98 u8 *src = walk->src.virt.addr; 99 u8 *dst = walk->dst.virt.addr; 100 unsigned int nbytes = walk->nbytes; 101 102 pagefault_disable(); 103 enable_kernel_vsx(); 104 aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key); 105 disable_kernel_vsx(); 106 pagefault_enable(); 107 108 crypto_xor(keystream, src, nbytes); 109 memcpy(dst, keystream, nbytes); 110 crypto_inc(ctrblk, AES_BLOCK_SIZE); 111 } 112 113 static int p8_aes_ctr_crypt(struct blkcipher_desc *desc, 114 struct scatterlist *dst, 115 struct scatterlist *src, unsigned int nbytes) 116 { 117 int ret; 118 u64 inc; 119 struct blkcipher_walk walk; 120 struct p8_aes_ctr_ctx *ctx = 121 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm)); 122 struct blkcipher_desc fallback_desc = { 123 .tfm = ctx->fallback, 124 .info = desc->info, 125 .flags = desc->flags 126 }; 127 128 if (in_interrupt()) { 129 ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src, 130 nbytes); 131 } else { 132 blkcipher_walk_init(&walk, dst, src, nbytes); 133 ret = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE); 134 while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) { 135 pagefault_disable(); 136 enable_kernel_vsx(); 137 aes_p8_ctr32_encrypt_blocks(walk.src.virt.addr, 138 walk.dst.virt.addr, 139 (nbytes & 140 AES_BLOCK_MASK) / 141 AES_BLOCK_SIZE, 142 &ctx->enc_key, 143 walk.iv); 144 disable_kernel_vsx(); 145 pagefault_enable(); 146 147 /* We need to update IV mostly for last bytes/round */ 148 inc = (nbytes & AES_BLOCK_MASK) / AES_BLOCK_SIZE; 149 if (inc > 0) 150 while (inc--) 151 crypto_inc(walk.iv, AES_BLOCK_SIZE); 152 153 nbytes &= AES_BLOCK_SIZE - 1; 154 ret = blkcipher_walk_done(desc, &walk, nbytes); 155 } 156 if (walk.nbytes) { 157 p8_aes_ctr_final(ctx, &walk); 158 ret = blkcipher_walk_done(desc, &walk, 0); 159 } 160 } 161 162 return ret; 163 } 164 165 struct crypto_alg p8_aes_ctr_alg = { 166 .cra_name = "ctr(aes)", 167 .cra_driver_name = "p8_aes_ctr", 168 .cra_module = THIS_MODULE, 169 .cra_priority = 2000, 170 .cra_type = &crypto_blkcipher_type, 171 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK, 172 .cra_alignmask = 0, 173 .cra_blocksize = 1, 174 .cra_ctxsize = sizeof(struct p8_aes_ctr_ctx), 175 .cra_init = p8_aes_ctr_init, 176 .cra_exit = p8_aes_ctr_exit, 177 .cra_blkcipher = { 178 .ivsize = AES_BLOCK_SIZE, 179 .min_keysize = AES_MIN_KEY_SIZE, 180 .max_keysize = AES_MAX_KEY_SIZE, 181 .setkey = p8_aes_ctr_setkey, 182 .encrypt = p8_aes_ctr_crypt, 183 .decrypt = p8_aes_ctr_crypt, 184 }, 185 }; 186