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 <crypto/skcipher.h> 31 32 #include "aesp8-ppc.h" 33 34 struct p8_aes_ctr_ctx { 35 struct crypto_sync_skcipher *fallback; 36 struct aes_key enc_key; 37 }; 38 39 static int p8_aes_ctr_init(struct crypto_tfm *tfm) 40 { 41 const char *alg = crypto_tfm_alg_name(tfm); 42 struct crypto_sync_skcipher *fallback; 43 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); 44 45 fallback = crypto_alloc_sync_skcipher(alg, 0, 46 CRYPTO_ALG_NEED_FALLBACK); 47 if (IS_ERR(fallback)) { 48 printk(KERN_ERR 49 "Failed to allocate transformation for '%s': %ld\n", 50 alg, PTR_ERR(fallback)); 51 return PTR_ERR(fallback); 52 } 53 54 crypto_sync_skcipher_set_flags( 55 fallback, 56 crypto_skcipher_get_flags((struct crypto_skcipher *)tfm)); 57 ctx->fallback = fallback; 58 59 return 0; 60 } 61 62 static void p8_aes_ctr_exit(struct crypto_tfm *tfm) 63 { 64 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); 65 66 if (ctx->fallback) { 67 crypto_free_sync_skcipher(ctx->fallback); 68 ctx->fallback = NULL; 69 } 70 } 71 72 static int p8_aes_ctr_setkey(struct crypto_tfm *tfm, const u8 *key, 73 unsigned int keylen) 74 { 75 int ret; 76 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); 77 78 preempt_disable(); 79 pagefault_disable(); 80 enable_kernel_vsx(); 81 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key); 82 disable_kernel_vsx(); 83 pagefault_enable(); 84 preempt_enable(); 85 86 ret += crypto_sync_skcipher_setkey(ctx->fallback, key, keylen); 87 return ret; 88 } 89 90 static 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 preempt_disable(); 100 pagefault_disable(); 101 enable_kernel_vsx(); 102 aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key); 103 disable_kernel_vsx(); 104 pagefault_enable(); 105 preempt_enable(); 106 107 crypto_xor_cpy(dst, keystream, src, nbytes); 108 crypto_inc(ctrblk, AES_BLOCK_SIZE); 109 } 110 111 static int p8_aes_ctr_crypt(struct blkcipher_desc *desc, 112 struct scatterlist *dst, 113 struct scatterlist *src, unsigned int nbytes) 114 { 115 int ret; 116 u64 inc; 117 struct blkcipher_walk walk; 118 struct p8_aes_ctr_ctx *ctx = 119 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm)); 120 121 if (in_interrupt()) { 122 SYNC_SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback); 123 skcipher_request_set_sync_tfm(req, ctx->fallback); 124 skcipher_request_set_callback(req, desc->flags, NULL, NULL); 125 skcipher_request_set_crypt(req, src, dst, nbytes, desc->info); 126 ret = crypto_skcipher_encrypt(req); 127 skcipher_request_zero(req); 128 } else { 129 blkcipher_walk_init(&walk, dst, src, nbytes); 130 ret = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE); 131 while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) { 132 preempt_disable(); 133 pagefault_disable(); 134 enable_kernel_vsx(); 135 aes_p8_ctr32_encrypt_blocks(walk.src.virt.addr, 136 walk.dst.virt.addr, 137 (nbytes & 138 AES_BLOCK_MASK) / 139 AES_BLOCK_SIZE, 140 &ctx->enc_key, 141 walk.iv); 142 disable_kernel_vsx(); 143 pagefault_enable(); 144 preempt_enable(); 145 146 /* We need to update IV mostly for last bytes/round */ 147 inc = (nbytes & AES_BLOCK_MASK) / AES_BLOCK_SIZE; 148 if (inc > 0) 149 while (inc--) 150 crypto_inc(walk.iv, AES_BLOCK_SIZE); 151 152 nbytes &= AES_BLOCK_SIZE - 1; 153 ret = blkcipher_walk_done(desc, &walk, nbytes); 154 } 155 if (walk.nbytes) { 156 p8_aes_ctr_final(ctx, &walk); 157 ret = blkcipher_walk_done(desc, &walk, 0); 158 } 159 } 160 161 return ret; 162 } 163 164 struct crypto_alg p8_aes_ctr_alg = { 165 .cra_name = "ctr(aes)", 166 .cra_driver_name = "p8_aes_ctr", 167 .cra_module = THIS_MODULE, 168 .cra_priority = 2000, 169 .cra_type = &crypto_blkcipher_type, 170 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK, 171 .cra_alignmask = 0, 172 .cra_blocksize = 1, 173 .cra_ctxsize = sizeof(struct p8_aes_ctr_ctx), 174 .cra_init = p8_aes_ctr_init, 175 .cra_exit = p8_aes_ctr_exit, 176 .cra_blkcipher = { 177 .ivsize = AES_BLOCK_SIZE, 178 .min_keysize = AES_MIN_KEY_SIZE, 179 .max_keysize = AES_MAX_KEY_SIZE, 180 .setkey = p8_aes_ctr_setkey, 181 .encrypt = p8_aes_ctr_crypt, 182 .decrypt = p8_aes_ctr_crypt, 183 }, 184 }; 185