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|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Glue code for AES implementation for SPE instructions (PPC)
*
* Based on generic implementation. The assembler module takes care
* about the SPE registers so it can run from interrupt context.
*
* Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de>
*/
#include <crypto/aes.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/crypto.h>
#include <asm/byteorder.h>
#include <asm/switch_to.h>
#include <crypto/algapi.h>
#include <crypto/xts.h>
/*
* MAX_BYTES defines the number of bytes that are allowed to be processed
* between preempt_disable() and preempt_enable(). e500 cores can issue two
* instructions per clock cycle using one 32/64 bit unit (SU1) and one 32
* bit unit (SU2). One of these can be a memory access that is executed via
* a single load and store unit (LSU). XTS-AES-256 takes ~780 operations per
* 16 byte block block or 25 cycles per byte. Thus 768 bytes of input data
* will need an estimated maximum of 20,000 cycles. Headroom for cache misses
* included. Even with the low end model clocked at 667 MHz this equals to a
* critical time window of less than 30us. The value has been chosen to
* process a 512 byte disk block in one or a large 1400 bytes IPsec network
* packet in two runs.
*
*/
#define MAX_BYTES 768
struct ppc_aes_ctx {
u32 key_enc[AES_MAX_KEYLENGTH_U32];
u32 key_dec[AES_MAX_KEYLENGTH_U32];
u32 rounds;
};
struct ppc_xts_ctx {
u32 key_enc[AES_MAX_KEYLENGTH_U32];
u32 key_dec[AES_MAX_KEYLENGTH_U32];
u32 key_twk[AES_MAX_KEYLENGTH_U32];
u32 rounds;
};
extern void ppc_encrypt_aes(u8 *out, const u8 *in, u32 *key_enc, u32 rounds);
extern void ppc_decrypt_aes(u8 *out, const u8 *in, u32 *key_dec, u32 rounds);
extern void ppc_encrypt_ecb(u8 *out, const u8 *in, u32 *key_enc, u32 rounds,
u32 bytes);
extern void ppc_decrypt_ecb(u8 *out, const u8 *in, u32 *key_dec, u32 rounds,
u32 bytes);
extern void ppc_encrypt_cbc(u8 *out, const u8 *in, u32 *key_enc, u32 rounds,
u32 bytes, u8 *iv);
extern void ppc_decrypt_cbc(u8 *out, const u8 *in, u32 *key_dec, u32 rounds,
u32 bytes, u8 *iv);
extern void ppc_crypt_ctr (u8 *out, const u8 *in, u32 *key_enc, u32 rounds,
u32 bytes, u8 *iv);
extern void ppc_encrypt_xts(u8 *out, const u8 *in, u32 *key_enc, u32 rounds,
u32 bytes, u8 *iv, u32 *key_twk);
extern void ppc_decrypt_xts(u8 *out, const u8 *in, u32 *key_dec, u32 rounds,
u32 bytes, u8 *iv, u32 *key_twk);
extern void ppc_expand_key_128(u32 *key_enc, const u8 *key);
extern void ppc_expand_key_192(u32 *key_enc, const u8 *key);
extern void ppc_expand_key_256(u32 *key_enc, const u8 *key);
extern void ppc_generate_decrypt_key(u32 *key_dec,u32 *key_enc,
unsigned int key_len);
static void spe_begin(void)
{
/* disable preemption and save users SPE registers if required */
preempt_disable();
enable_kernel_spe();
}
static void spe_end(void)
{
disable_kernel_spe();
/* reenable preemption */
preempt_enable();
}
static int ppc_aes_setkey(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct ppc_aes_ctx *ctx = crypto_tfm_ctx(tfm);
if (key_len != AES_KEYSIZE_128 &&
key_len != AES_KEYSIZE_192 &&
key_len != AES_KEYSIZE_256) {
tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
switch (key_len) {
case AES_KEYSIZE_128:
ctx->rounds = 4;
ppc_expand_key_128(ctx->key_enc, in_key);
break;
case AES_KEYSIZE_192:
ctx->rounds = 5;
ppc_expand_key_192(ctx->key_enc, in_key);
break;
case AES_KEYSIZE_256:
ctx->rounds = 6;
ppc_expand_key_256(ctx->key_enc, in_key);
break;
}
ppc_generate_decrypt_key(ctx->key_dec, ctx->key_enc, key_len);
return 0;
}
static int ppc_xts_setkey(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len)
{
struct ppc_xts_ctx *ctx = crypto_tfm_ctx(tfm);
int err;
err = xts_check_key(tfm, in_key, key_len);
if (err)
return err;
key_len >>= 1;
if (key_len != AES_KEYSIZE_128 &&
key_len != AES_KEYSIZE_192 &&
key_len != AES_KEYSIZE_256) {
tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
switch (key_len) {
case AES_KEYSIZE_128:
ctx->rounds = 4;
ppc_expand_key_128(ctx->key_enc, in_key);
ppc_expand_key_128(ctx->key_twk, in_key + AES_KEYSIZE_128);
break;
case AES_KEYSIZE_192:
ctx->rounds = 5;
ppc_expand_key_192(ctx->key_enc, in_key);
ppc_expand_key_192(ctx->key_twk, in_key + AES_KEYSIZE_192);
break;
case AES_KEYSIZE_256:
ctx->rounds = 6;
ppc_expand_key_256(ctx->key_enc, in_key);
ppc_expand_key_256(ctx->key_twk, in_key + AES_KEYSIZE_256);
break;
}
ppc_generate_decrypt_key(ctx->key_dec, ctx->key_enc, key_len);
return 0;
}
static void ppc_aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
struct ppc_aes_ctx *ctx = crypto_tfm_ctx(tfm);
spe_begin();
ppc_encrypt_aes(out, in, ctx->key_enc, ctx->rounds);
spe_end();
}
static void ppc_aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
struct ppc_aes_ctx *ctx = crypto_tfm_ctx(tfm);
spe_begin();
ppc_decrypt_aes(out, in, ctx->key_dec, ctx->rounds);
spe_end();
}
static int ppc_ecb_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
struct scatterlist *src, unsigned int nbytes)
{
struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
struct blkcipher_walk walk;
unsigned int ubytes;
int err;
desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
blkcipher_walk_init(&walk, dst, src, nbytes);
err = blkcipher_walk_virt(desc, &walk);
while ((nbytes = walk.nbytes)) {
ubytes = nbytes > MAX_BYTES ?
nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
nbytes -= ubytes;
spe_begin();
ppc_encrypt_ecb(walk.dst.virt.addr, walk.src.virt.addr,
ctx->key_enc, ctx->rounds, nbytes);
spe_end();
err = blkcipher_walk_done(desc, &walk, ubytes);
}
return err;
}
static int ppc_ecb_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,<
|