drivers/crypto/vmx/aes_cbc.c

   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 };