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 "Failed to allocate transformation for '%s': %ld\n",
52                alg, PTR_ERR(fallback));
53        return PTR_ERR(fallback);
54    }
55    printk(KERN_INFO "Using '%s' as fallback implementation.\n",
56            crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback));
57
58    crypto_cipher_set_flags(fallback,
59            crypto_cipher_get_flags((struct crypto_cipher *) tfm));
60    ctx->fallback = fallback;
61
62    return 0;
63}
64
65static void p8_aes_exit(struct crypto_tfm *tfm)
66{
67    struct p8_aes_ctx *ctx = crypto_tfm_ctx(tfm);
68
69    if (ctx->fallback) {
70        crypto_free_cipher(ctx->fallback);
71        ctx->fallback = NULL;
72    }
73}
74
75static int p8_aes_setkey(struct crypto_tfm *tfm, const u8 *key,
76    unsigned int keylen)
77{
78    int ret;
79    struct p8_aes_ctx *ctx = crypto_tfm_ctx(tfm);
80
81    pagefault_disable();
82    enable_kernel_altivec();
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    pagefault_enable();
87
88    ret += crypto_cipher_setkey(ctx->fallback, key, keylen);
89    return ret;
90}
91
92static 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        pagefault_disable();
100        enable_kernel_altivec();
101        enable_kernel_vsx();
102        aes_p8_encrypt(src, dst, &ctx->enc_key);
103        pagefault_enable();
104    }
105}
106
107static void p8_aes_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
108{
109    struct p8_aes_ctx *ctx = crypto_tfm_ctx(tfm);
110
111    if (in_interrupt()) {
112        crypto_cipher_decrypt_one(ctx->fallback, dst, src);
113    } else {
114        pagefault_disable();
115        enable_kernel_altivec();
116        enable_kernel_vsx();
117        aes_p8_decrypt(src, dst, &ctx->dec_key);
118        pagefault_enable();
119    }
120}
121
122struct crypto_alg p8_aes_alg = {
123    .cra_name = "aes",
124    .cra_driver_name = "p8_aes",
125    .cra_module = THIS_MODULE,
126    .cra_priority = 1000,
127    .cra_type = NULL,
128    .cra_flags = CRYPTO_ALG_TYPE_CIPHER | CRYPTO_ALG_NEED_FALLBACK,
129    .cra_alignmask = 0,
130    .cra_blocksize = AES_BLOCK_SIZE,
131    .cra_ctxsize = sizeof(struct p8_aes_ctx),
132    .cra_init = p8_aes_init,
133    .cra_exit = p8_aes_exit,
134    .cra_cipher = {
135        .cia_min_keysize = AES_MIN_KEY_SIZE,
136        .cia_max_keysize = AES_MAX_KEY_SIZE,
137        .cia_setkey = p8_aes_setkey,
138        .cia_encrypt = p8_aes_encrypt,
139        .cia_decrypt = p8_aes_decrypt,
140    },
141};
142
143