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// SPDX-License-Identifier: GPL-2.0-only
/*
* AES XTS routines supporting VMX In-core instructions on Power 8
*
* Copyright (C) 2015 International Business Machines Inc.
*
* Author: Leonidas S. Barbosa <leosilva@linux.vnet.ibm.com>
*/
#include <asm/simd.h>
#include <asm/switch_to.h>
#include <crypto/aes.h>
#include <crypto/internal/simd.h>
#include <crypto/internal/skcipher.h>
#include <crypto/xts.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include "aesp8-ppc.h"
struct p8_aes_xts_ctx {
struct crypto_skcipher *fallback;
struct aes_key enc_key;
struct aes_key dec_key;
struct aes_key tweak_key;
};
static int p8_aes_xts_init(struct crypto_skcipher *tfm)
{
struct p8_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
struct crypto_skcipher *fallback;
fallback = crypto_alloc_skcipher("xts(aes)", 0,
CRYPTO_ALG_NEED_FALLBACK |
CRYPTO_ALG_ASYNC);
if (IS_ERR(fallback)) {
pr_err("Failed to allocate xts(aes) fallback: %ld\n",
PTR_ERR(fallback));
return PTR_ERR(fallback);
}
crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) +
crypto_skcipher_reqsize(fallback));
ctx->fallback = fallback;
return 0;
}
static void p8_aes_xts_exit(struct crypto_skcipher *tfm)
{
struct p8_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
crypto_free_skcipher(ctx->fallback);
}
static int p8_aes_xts_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keylen)
{
struct p8_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
int ret;
ret = xts_verify_key(tfm, key, keylen);
if (ret)
return ret;
preempt_disable();
pagefault_disable();
enable_kernel_vsx();
ret = aes_p8_set_encrypt_key(key + keylen/2, (keylen/2) * 8, &ctx->tweak_key);
ret |= aes_p8_set_encrypt_key(key, (keylen/2) * 8, &ctx->enc_key);
ret |= aes_p8_set_decrypt_key(key, (keylen/2) * 8, &ctx->dec_key);
disable_kernel_vsx();
pagefault_enable();
preempt_enable();
ret |= crypto_skcipher_setkey(ctx->fallback, key, keylen);
return ret ? -EINVAL : 0;
}
static int p8_aes_xts_crypt(struct skcipher_request *req, int enc)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
const struct p8_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
unsigned int nbytes;
u8 tweak[AES_BLOCK_SIZE];
int ret;
if (req->cryptlen < AES_BLOCK_SIZE)
return -EINVAL;
if (!crypto_simd_usable() || (req->cryptlen % XTS_BLOCK_SIZE) != 0) {
struct skcipher_request *subreq = skcipher_request_ctx(req);
*subreq = *req;
skcipher_request_set_tfm(subreq, ctx->fallback);
return enc ? crypto_skcipher_encrypt(subreq) :
crypto_skcipher_decrypt(subreq);
}
ret = skcipher_walk_virt(&walk, req, false);
if (ret)
return ret;
preempt_disable();
pagefault_disable();
enable_kernel_vsx();
aes_p8_encrypt(walk.iv, tweak, &ctx->tweak_key);
disable_kernel_vsx();
pagefault_enable();
preempt_enable();
while ((nbytes = walk.nbytes) != 0) {
preempt_disable();
pagefault_disable();
enable_kernel_vsx();
if (enc)
aes_p8_xts_encrypt(walk.src.virt.addr,
walk.dst.virt.addr,
round_down(nbytes, AES_BLOCK_SIZE),
&ctx->enc_key, NULL, tweak);
else
aes_p8_xts_decrypt(walk.src.virt.addr,
walk.dst.virt.addr,
round_down(nbytes, AES_BLOCK_SIZE),
&ctx->dec_key, NULL, tweak);
disable_kernel_vsx();
pagefault_enable();
preempt_enable();
ret = skcipher_walk_done(&walk, nbytes % AES_BLOCK_SIZE);
}
return ret;
}
static int p8_aes_xts_encrypt(struct skcipher_request *req)
{
return p8_aes_xts_crypt(req, 1);
}
static int p8_aes_xts_decrypt(struct skcipher_request *req)
{
return p8_aes_xts_crypt(req, 0);
}
struct skcipher_alg p8_aes_xts_alg = {
.base.cra_name = "xts(aes)",
.base.cra_driver_name = "p8_aes_xts",
.base.cra_module = THIS_MODULE,
.base.cra_priority = 2000,
.base.cra_flags = CRYPTO_ALG_NEED_FALLBACK,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct p8_aes_xts_ctx),
.setkey = p8_aes_xts_setkey,
.encrypt = p8_aes_xts_encrypt,
.decrypt = p8_aes_xts_decrypt,
.init = p8_aes_xts_init,
.exit = p8_aes_xts_exit,
.min_keysize = 2 * AES_MIN_KEY_SIZE,
.max_keysize = 2 * AES_MAX_KEY_SIZE,
.ivsize = AES_BLOCK_SIZE,
};
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