drivers/crypto/vmx/aes.c

   1 /**
   2  * AES 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
  30 #include "aesp8-ppc.h"
  31
  32 struct p8_aes_ctx {
  33         struct crypto_cipher *fallback;
  34         struct aes_key enc_key;
  35         struct aes_key dec_key;
  36 };
  37
  38 static int p8_aes_init(struct crypto_tfm *tfm)
  39 {
  40         const char *alg = crypto_tfm_alg_name(tfm);
  41         struct crypto_cipher *fallback;
  42         struct p8_aes_ctx *ctx = crypto_tfm_ctx(tfm);
  43
  44         fallback = crypto_alloc_cipher(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
  45         if (IS_ERR(fallback)) {
  46                 printk(KERN_ERR
  47                        "Failed to allocate transformation for '%s': %ld\n",
  48                        alg, PTR_ERR(fallback));
  49                 return PTR_ERR(fallback);
  50         }
  51         printk(KERN_INFO "Using '%s' as fallback implementation.\n",
  52                crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback));
  53
  54         crypto_cipher_set_flags(fallback,
  55                                 crypto_cipher_get_flags((struct
  56                                                          crypto_cipher *)
  57                                                         tfm));
  58         ctx->fallback = fallback;
  59
  60         return 0;
  61 }
  62
  63 static void p8_aes_exit(struct crypto_tfm *tfm)
  64 {
  65         struct p8_aes_ctx *ctx = crypto_tfm_ctx(tfm);
  66
  67         if (ctx->fallback) {
  68                 crypto_free_cipher(ctx->fallback);
  69                 ctx->fallback = NULL;
  70         }
  71 }
  72
  73 static int p8_aes_setkey(struct crypto_tfm *tfm, const u8 *key,
  74                          unsigned int keylen)
  75 {
  76         int ret;
  77         struct p8_aes_ctx *ctx = crypto_tfm_ctx(tfm);
  78
  79         preempt_disable();
  80         pagefault_disable();
  81         enable_kernel_vsx();
  82         ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
  83         ret += aes_p8_set_decrypt_key(key, keylen * 8, &ctx->dec_key);
  84         disable_kernel_vsx();
  85         pagefault_enable();
  86         preempt_enable();
  87
  88         ret += crypto_cipher_setkey(ctx->fallback, key, keylen);
  89         return ret;
  90 }
  91
  92 static void p8_aes_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
  93 {
  94         struct p8_aes_ctx *ctx = crypto_tfm_ctx(tfm);
  95
  96         if (in_interrupt()) {
  97                 crypto_cipher_encrypt_one(ctx->fallback, dst, src);
  98         } else {
  99                 preempt_disable();
 100                 pagefault_disable();
 101                 enable_kernel_vsx();
 102                 aes_p8_encrypt(src, dst, &ctx->enc_key);
 103                 disable_kernel_vsx();
 104                 pagefault_enable();
 105                 preempt_enable();
 106         }
 107 }
 108
 109 static void p8_aes_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
 110 {
 111         struct p8_aes_ctx *ctx = crypto_tfm_ctx(tfm);
 112
 113         if (in_interrupt()) {
 114                 crypto_cipher_decrypt_one(ctx->fallback, dst, src);
 115         } else {
 116                 preempt_disable();
 117                 pagefault_disable();
 118                 enable_kernel_vsx();
 119                 aes_p8_decrypt(src, dst, &ctx->dec_key);
 120                 disable_kernel_vsx();
 121                 pagefault_enable();
 122                 preempt_enable();
 123         }
 124 }
 125
 126 struct crypto_alg p8_aes_alg = {
 127         .cra_name = "aes",
 128         .cra_driver_name = "p8_aes",
 129         .cra_module = THIS_MODULE,
 130         .cra_priority = 1000,
 131         .cra_type = NULL,
 132         .cra_flags = CRYPTO_ALG_TYPE_CIPHER | CRYPTO_ALG_NEED_FALLBACK,
 133         .cra_alignmask = 0,
 134         .cra_blocksize = AES_BLOCK_SIZE,
 135         .cra_ctxsize = sizeof(struct p8_aes_ctx),
 136         .cra_init = p8_aes_init,
 137         .cra_exit = p8_aes_exit,
 138         .cra_cipher = {
 139                        .cia_min_keysize = AES_MIN_KEY_SIZE,
 140                        .cia_max_keysize = AES_MAX_KEY_SIZE,
 141                        .cia_setkey = p8_aes_setkey,
 142                        .cia_encrypt = p8_aes_encrypt,
 143                        .cia_decrypt = p8_aes_decrypt,
 144         },
 145 };