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
18struct p8_aes_ctr_ctx {
19	struct crypto_skcipher *fallback;
20	struct aes_key enc_key;
21};
22
23static 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
43static 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
50static 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
69static 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
90static 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
132struct 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