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};