LXR linux/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
  32struct p8_aes_ctx {
  33        struct crypto_cipher *fallback;
  34        struct aes_key enc_key;
  35        struct aes_key dec_key;
  36};
  37
  38static int p8_aes_init(struct crypto_tfm *tfm)
  39{
  40        const char *alg;
  41        struct crypto_cipher *fallback;
  42        struct p8_aes_ctx *ctx = crypto_tfm_ctx(tfm);
  43
  44        if (!(alg = crypto_tfm_alg_name(tfm))) {
  45                printk(KERN_ERR "Failed to get algorithm name.\n");
  46                return -ENOENT;
  47        }
  48
  49        fallback = crypto_alloc_cipher(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_cipher_set_flags(fallback,
  60                                crypto_cipher_get_flags((struct
  61                                                         crypto_cipher *)
  62                                                        tfm));
  63        ctx->fallback = fallback;
  64
  65        return 0;
  66}
  67
  68static void p8_aes_exit(struct crypto_tfm *tfm)
  69{
  70        struct p8_aes_ctx *ctx = crypto_tfm_ctx(tfm);
  71
  72        if (ctx->fallback) {
  73                crypto_free_cipher(ctx->fallback);
  74                ctx->fallback = NULL;
  75        }
  76}
  77
  78static int p8_aes_setkey(struct crypto_tfm *tfm, const u8 *key,
  79                         unsigned int keylen)
  80{
  81        int ret;
  82        struct p8_aes_ctx *ctx = crypto_tfm_ctx(tfm);
  83
  84        preempt_disable();
  85        pagefault_disable();
  86        enable_kernel_vsx();
  87        ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
  88        ret += aes_p8_set_decrypt_key(key, keylen * 8, &ctx->dec_key);
  89        pagefault_enable();
  90        preempt_enable();
  91
  92        ret += crypto_cipher_setkey(ctx->fallback, key, keylen);
  93        return ret;
  94}
  95
  96static void p8_aes_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
  97{
  98        struct p8_aes_ctx *ctx = crypto_tfm_ctx(tfm);
  99
 100        if (in_interrupt()) {
 101                crypto_cipher_encrypt_one(ctx->fallback, dst, src);
 102        } else {
 103                preempt_disable();
 104                pagefault_disable();
 105                enable_kernel_vsx();
 106                aes_p8_encrypt(src, dst, &ctx->enc_key);
 107                pagefault_enable();
 108                preempt_enable();
 109        }
 110}
 111
 112static void p8_aes_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
 113{
 114        struct p8_aes_ctx *ctx = crypto_tfm_ctx(tfm);
 115
 116        if (in_interrupt()) {
 117                crypto_cipher_decrypt_one(ctx->fallback, dst, src);
 118        } else {
 119                preempt_disable();
 120                pagefault_disable();
 121                enable_kernel_vsx();
 122                aes_p8_decrypt(src, dst, &ctx->dec_key);
 123                pagefault_enable();
 124                preempt_enable();
 125        }
 126}
 127
 128struct crypto_alg p8_aes_alg = {
 129        .cra_name = "aes",
 130        .cra_driver_name = "p8_aes",
 131        .cra_module = THIS_MODULE,
 132        .cra_priority = 1000,
 133        .cra_type = NULL,
 134        .cra_flags = CRYPTO_ALG_TYPE_CIPHER | CRYPTO_ALG_NEED_FALLBACK,
 135        .cra_alignmask = 0,
 136        .cra_blocksize = AES_BLOCK_SIZE,
 137        .cra_ctxsize = sizeof(struct p8_aes_ctx),
 138        .cra_init = p8_aes_init,
 139        .cra_exit = p8_aes_exit,
 140        .cra_cipher = {
 141                       .cia_min_keysize = AES_MIN_KEY_SIZE,
 142                       .cia_max_keysize = AES_MAX_KEY_SIZE,
 143                       .cia_setkey = p8_aes_setkey,
 144                       .cia_encrypt = p8_aes_encrypt,
 145                       .cia_decrypt = p8_aes_decrypt,
 146        },
 147};
 148