aes_ctr.c
// SPDX-License-Identifier: GPL-2.0-only
/**
* AES CTR routines supporting VMX instructions on the Power 8
*
* Copyright (C) 2015 International Business Machines Inc.
*
* Author: Marcelo Henrique Cerri <mhcerri@br.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 "aesp8-ppc.h"
struct p8_aes_ctr_ctx {
struct crypto_skcipher *fallback;
struct aes_key enc_key;
};
static int p8_aes_ctr_init(struct crypto_skcipher *tfm)
{
struct p8_aes_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
struct crypto_skcipher *fallback;
fallback = crypto_alloc_skcipher("ctr(aes)", 0,
CRYPTO_ALG_NEED_FALLBACK |
CRYPTO_ALG_ASYNC);
if (IS_ERR(fallback)) {
pr_err("Failed to allocate ctr(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_ctr_exit(struct crypto_skcipher *tfm)
{
struct p8_aes_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
crypto_free_skcipher(ctx->fallback);
}
static int p8_aes_ctr_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keylen)
{
struct p8_aes_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
int ret;
preempt_disable();
pagefault_disable();
enable_kernel_vsx();
ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
disable_kernel_vsx();
pagefault_enable();
preempt_enable();
ret |= crypto_skcipher_setkey(ctx->fallback, key, keylen);
return ret ? -EINVAL : 0;
}
static void p8_aes_ctr_final(const struct p8_aes_ctr_ctx *ctx,
struct skcipher_walk *walk)
{
u8 *ctrblk = walk->iv;
u8 keystream[AES_BLOCK_SIZE];
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
unsigned int nbytes = walk->nbytes;
preempt_disable();
pagefault_disable();
enable_kernel_vsx();
aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key);
disable_kernel_vsx();
pagefault_enable();
preempt_enable();
crypto_xor_cpy(dst, keystream, src, nbytes);
crypto_inc(ctrblk, AES_BLOCK_SIZE);
}
static int p8_aes_ctr_crypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
const struct p8_aes_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
unsigned int nbytes;
int ret;
if (!crypto_simd_usable()) {
struct skcipher_request *subreq = skcipher_request_ctx(req);
*subreq = *req;
skcipher_request_set_tfm(subreq, ctx->fallback);
return crypto_skcipher_encrypt(subreq);
}
ret = skcipher_walk_virt(&walk, req, false);
while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
preempt_disable();
pagefault_disable();
enable_kernel_vsx();
aes_p8_ctr32_encrypt_blocks(walk.src.virt.addr,
walk.dst.virt.addr,
nbytes / AES_BLOCK_SIZE,
&ctx->enc_key, walk.iv);
disable_kernel_vsx();
pagefault_enable();
preempt_enable();
do {
crypto_inc(walk.iv, AES_BLOCK_SIZE);
} while ((nbytes -= AES_BLOCK_SIZE) >= AES_BLOCK_SIZE);
ret = skcipher_walk_done(&walk, nbytes);
}
if (nbytes) {
p8_aes_ctr_final(ctx, &walk);
ret = skcipher_walk_done(&walk, 0);
}
return ret;
}
struct skcipher_alg p8_aes_ctr_alg = {
.base.cra_name = "ctr(aes)",
.base.cra_driver_name = "p8_aes_ctr",
.base.cra_module = THIS_MODULE,
.base.cra_priority = 2000,
.base.cra_flags = CRYPTO_ALG_NEED_FALLBACK,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct p8_aes_ctr_ctx),
.setkey = p8_aes_ctr_setkey,
.encrypt = p8_aes_ctr_crypt,
.decrypt = p8_aes_ctr_crypt,
.init = p8_aes_ctr_init,
.exit = p8_aes_ctr_exit,
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.ivsize = AES_BLOCK_SIZE,
.chunksize = AES_BLOCK_SIZE,
};