1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * AES CTR routines supporting VMX instructions on the Power 8
4 *
5 * Copyright (C) 2015 International Business Machines Inc.
6 *
7 * Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com>
8 */
9
10 #include <asm/simd.h>
11 #include <asm/switch_to.h>
12 #include <crypto/aes.h>
13 #include <crypto/internal/simd.h>
14 #include <crypto/internal/skcipher.h>
15
16 #include "aesp8-ppc.h"
17
18 struct p8_aes_ctr_ctx {
19 struct crypto_skcipher *fallback;
20 struct aes_key enc_key;
21 };
22
23 static int p8_aes_ctr_init(struct crypto_skcipher *tfm)
24 {
25 struct p8_aes_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
26 struct crypto_skcipher *fallback;
27
28 fallback = crypto_alloc_skcipher("ctr(aes)", 0,
29 CRYPTO_ALG_NEED_FALLBACK |
30 CRYPTO_ALG_ASYNC);
31 if (IS_ERR(fallback)) {
32 pr_err("Failed to allocate ctr(aes) fallback: %ld\n",
33 PTR_ERR(fallback));
34 return PTR_ERR(fallback);
35 }
36
37 crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) +
38 crypto_skcipher_reqsize(fallback));
39 ctx->fallback = fallback;
40 return 0;
41 }
42
43 static void p8_aes_ctr_exit(struct crypto_skcipher *tfm)
44 {
45 struct p8_aes_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
46
47 crypto_free_skcipher(ctx->fallback);
48 }
49
50 static int p8_aes_ctr_setkey(struct crypto_skcipher *tfm, const u8 *key,
51 unsigned int keylen)
52 {
53 struct p8_aes_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
54 int ret;
55
56 preempt_disable();
57 pagefault_disable();
58 enable_kernel_vsx();
59 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
60 disable_kernel_vsx();
61 pagefault_enable();
62 preempt_enable();
63
64 ret |= crypto_skcipher_setkey(ctx->fallback, key, keylen);
65
66 return ret ? -EINVAL : 0;
67 }
68
69 static void p8_aes_ctr_final(const struct p8_aes_ctr_ctx *ctx,
70 struct skcipher_walk *walk)
71 {
72 u8 *ctrblk = walk->iv;
73 u8 keystream[AES_BLOCK_SIZE];
74 u8 *src = walk->src.virt.addr;
75 u8 *dst = walk->dst.virt.addr;
76 unsigned int nbytes = walk->nbytes;
77
78 preempt_disable();
79 pagefault_disable();
80 enable_kernel_vsx();
81 aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key);
82 disable_kernel_vsx();
83 pagefault_enable();
84 preempt_enable();
85
86 crypto_xor_cpy(dst, keystream, src, nbytes);
87 crypto_inc(ctrblk, AES_BLOCK_SIZE);
88 }
89
90 static int p8_aes_ctr_crypt(struct skcipher_request *req)
91 {
92 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
93 const struct p8_aes_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
94 struct skcipher_walk walk;
95 unsigned int nbytes;
96 int ret;
97
98 if (!crypto_simd_usable()) {
99 struct skcipher_request *subreq = skcipher_request_ctx(req);
100
101 *subreq = *req;
102 skcipher_request_set_tfm(subreq, ctx->fallback);
103 return crypto_skcipher_encrypt(subreq);
104 }
105
106 ret = skcipher_walk_virt(&walk, req, false);
107 while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
108 preempt_disable();
109 pagefault_disable();
110 enable_kernel_vsx();
111 aes_p8_ctr32_encrypt_blocks(walk.src.virt.addr,
112 walk.dst.virt.addr,
113 nbytes / AES_BLOCK_SIZE,
114 &ctx->enc_key, walk.iv);
115 disable_kernel_vsx();
116 pagefault_enable();
117 preempt_enable();
118
119 do {
120 crypto_inc(walk.iv, AES_BLOCK_SIZE);
121 } while ((nbytes -= AES_BLOCK_SIZE) >= AES_BLOCK_SIZE);
122
123 ret = skcipher_walk_done(&walk, nbytes);
124 }
125 if (nbytes) {
126 p8_aes_ctr_final(ctx, &walk);
127 ret = skcipher_walk_done(&walk, 0);
128 }
129 return ret;
130 }
131
132 struct skcipher_alg p8_aes_ctr_alg = {
133 .base.cra_name = "ctr(aes)",
134 .base.cra_driver_name = "p8_aes_ctr",
135 .base.cra_module = THIS_MODULE,
136 .base.cra_priority = 2000,
137 .base.cra_flags = CRYPTO_ALG_NEED_FALLBACK,
138 .base.cra_blocksize = 1,
139 .base.cra_ctxsize = sizeof(struct p8_aes_ctr_ctx),
140 .setkey = p8_aes_ctr_setkey,
141 .encrypt = p8_aes_ctr_crypt,
142 .decrypt = p8_aes_ctr_crypt,
143 .init = p8_aes_ctr_init,
144 .exit = p8_aes_ctr_exit,
145 .min_keysize = AES_MIN_KEY_SIZE,
146 .max_keysize = AES_MAX_KEY_SIZE,
147 .ivsize = AES_BLOCK_SIZE,
148 .chunksize = AES_BLOCK_SIZE,
149 };
150
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