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 32struct p8_aes_ctr_ctx { 33 struct crypto_blkcipher *fallback; 34 struct aes_key enc_key; 35}; 36 37static 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 = crypto_alloc_blkcipher(alg, 0 ,CRYPTO_ALG_NEED_FALLBACK); 49 if (IS_ERR(fallback)) { 50 printk(KERN_ERR "Failed to allocate transformation for '%s': %ld\n", 51 alg, PTR_ERR(fallback)); 52 return PTR_ERR(fallback); 53 } 54 printk(KERN_INFO "Using '%s' as fallback implementation.\n", 55 crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback)); 56 57 crypto_blkcipher_set_flags(fallback, 58 crypto_blkcipher_get_flags((struct crypto_blkcipher *) tfm)); 59 ctx->fallback = fallback; 60 61 return 0; 62} 63 64static void p8_aes_ctr_exit(struct crypto_tfm *tfm) 65{ 66 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); 67 68 if (ctx->fallback) { 69 crypto_free_blkcipher(ctx->fallback); 70 ctx->fallback = NULL; 71 } 72} 73 74static int p8_aes_ctr_setkey(struct crypto_tfm *tfm, const u8 *key, 75 unsigned int keylen) 76{ 77 int ret; 78 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); 79 80 pagefault_disable(); 81 enable_kernel_altivec(); 82 enable_kernel_vsx(); 83 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key); 84 pagefault_enable(); 85 86 ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen); 87 return ret; 88} 89 90static void p8_aes_ctr_final(struct p8_aes_ctr_ctx *ctx, 91 struct blkcipher_walk *walk) 92{ 93 u8 *ctrblk = walk->iv; 94 u8 keystream[AES_BLOCK_SIZE]; 95 u8 *src = walk->src.virt.addr; 96 u8 *dst = walk->dst.virt.addr; 97 unsigned int nbytes = walk->nbytes; 98 99 pagefault_disable(); 100 enable_kernel_altivec(); 101 enable_kernel_vsx(); 102 aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key); 103 pagefault_enable(); 104 105 crypto_xor(keystream, src, nbytes); 106 memcpy(dst, keystream, nbytes); 107 crypto_inc(ctrblk, AES_BLOCK_SIZE); 108} 109 110static int p8_aes_ctr_crypt(struct blkcipher_desc *desc, 111 struct scatterlist *dst, struct scatterlist *src, 112 unsigned int nbytes) 113{ 114 int ret; 115 struct blkcipher_walk walk; 116 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx( 117 crypto_blkcipher_tfm(desc->tfm)); 118 struct blkcipher_desc fallback_desc = { 119 .tfm = ctx->fallback, 120 .info = desc->info, 121 .flags = desc->flags 122 }; 123 124 if (in_interrupt()) { 125 ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src, nbytes); 126 } else { 127 blkcipher_walk_init(&walk, dst, src, nbytes); 128 ret = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE); 129 while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) { 130 pagefault_disable(); 131 enable_kernel_altivec(); 132 enable_kernel_vsx(); 133 aes_p8_ctr32_encrypt_blocks(walk.src.virt.addr, walk.dst.virt.addr, 134 (nbytes & AES_BLOCK_MASK)/AES_BLOCK_SIZE, &ctx->enc_key, walk.iv); 135 pagefault_enable(); 136 137 crypto_inc(walk.iv, AES_BLOCK_SIZE); 138 nbytes &= AES_BLOCK_SIZE - 1; 139 ret = blkcipher_walk_done(desc, &walk, nbytes); 140 } 141 if (walk.nbytes) { 142 p8_aes_ctr_final(ctx, &walk); 143 ret = blkcipher_walk_done(desc, &walk, 0); 144 } 145 } 146 147 return ret; 148} 149 150struct crypto_alg p8_aes_ctr_alg = { 151 .cra_name = "ctr(aes)", 152 .cra_driver_name = "p8_aes_ctr", 153 .cra_module = THIS_MODULE, 154 .cra_priority = 1000, 155 .cra_type = &crypto_blkcipher_type, 156 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK, 157 .cra_alignmask = 0, 158 .cra_blocksize = 1, 159 .cra_ctxsize = sizeof(struct p8_aes_ctr_ctx), 160 .cra_init = p8_aes_ctr_init, 161 .cra_exit = p8_aes_ctr_exit, 162 .cra_blkcipher = { 163 .ivsize = 0, 164 .min_keysize = AES_MIN_KEY_SIZE, 165 .max_keysize = AES_MAX_KEY_SIZE, 166 .setkey = p8_aes_ctr_setkey, 167 .encrypt = p8_aes_ctr_crypt, 168 .decrypt = p8_aes_ctr_crypt, 169 }, 170}; 171