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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/internal/skcipher.h>
#include <crypto/xts.h>
#include <crypto/gf128mul.h>
#include <crypto/scatterwalk.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);
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;
default:
return -EINVAL;
}
ppc_generate_decrypt_key(ctx->key_dec, ctx->key_enc, key_len);
return 0;
}
static int ppc_aes_setkey_skcipher(struct crypto_skcipher *tfm,
const u8 *in_key, unsigned int key_len)
{
return ppc_aes_setkey(crypto_skcipher_tfm(tfm), in_key, key_len);
}
static int ppc_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
unsigned int key_len)
{
struct ppc_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
int err;
err = xts_verify_key(tfm, in_key, key_len);
if (err)
return err;
key_len >>= 1;
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;
default:
return -EINVAL;
}
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_crypt(struct skcipher_request *req, bool enc)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct ppc_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
unsigned int nbytes;
int err;
err = skcipher_walk_virt(&walk, req, false);
while ((nbytes = walk.nbytes) != 0) {
nbytes = min_t(unsigned int, nbytes, MAX_BYTES);
nbytes = round_down(nbytes, AES_BLOCK_SIZE);
spe_begin();
if (enc)
ppc_encrypt_ecb(walk.dst.virt.addr, walk.src.virt.addr,
ctx->key_enc, ctx->rounds, nbytes);
else
ppc_decrypt_ecb(walk.dst.virt.addr, walk.src.virt.addr,
ctx->key_dec, ctx->rounds, nbytes);
spe_end();
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
}
return err;
}
static int ppc_ecb_encrypt(struct skcipher_request *req)
{
return ppc_ecb_crypt(req, true);
}
static int ppc_ecb_decrypt(struct skcipher_request *req)
{
return ppc_ecb_crypt(req, false);
}
static int ppc_cbc_crypt(struct skcipher_request *req, bool enc)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct ppc_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
unsigned int nbytes;
int err;
err = skcipher_walk_virt(&walk, req, false);
while ((nbytes = walk.nbytes) != 0) {
nbytes = min_t(unsigned int, nbytes, MAX_BYTES);
nbytes = round_down(nbytes, AES_BLOCK_SIZE);
spe_begin();
if (enc)
ppc_encrypt_cbc(walk.dst.virt.addr, walk.src.virt.addr,
ctx->key_enc, ctx->rounds, nbytes,
walk.iv);
else
ppc_decrypt_cbc(walk.dst.virt.addr, walk.src.virt.addr,
ctx->key_dec, ctx->rounds, nbytes,
walk.iv);
spe_end();
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
}
return err;
}
static int ppc_cbc_encrypt(struct skcipher_request *req)
{
return ppc_cbc_crypt(req, true);
}
static int ppc_cbc_decrypt(struct skcipher_request *req)
{
return ppc_cbc_crypt(req, false);
}
static int ppc_ctr_crypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct ppc_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
unsigned int nbytes;
int err;
err = skcipher_walk_virt(&walk, req, false);
while ((nbytes = walk.nbytes) != 0) {
nbytes = min_t(unsigned int, nbytes, MAX_BYTES);
if (nbytes < walk.total)
nbytes = round_down(nbytes, AES_BLOCK_SIZE);
spe_begin();
ppc_crypt_ctr(walk.dst.virt.addr, walk.src.virt.addr,
ctx->key_enc, ctx->rounds, nbytes, walk.iv);
spe_end();
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
}
return err;
}
static int ppc_xts_crypt(struct skcipher_request *req, bool enc)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct ppc_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
unsigned int nbytes;
int err;
u32 *twk;
err = skcipher_walk_virt(&walk, req, false);
twk = ctx->key_twk;
while ((nbytes = walk.nbytes) != 0) {
nbytes = min_t(unsigned int, nbytes, MAX_BYTES);
nbytes = round_down(nbytes, AES_BLOCK_SIZE);
spe_begin();
if (enc)
ppc_encrypt_xts(walk.dst.virt.addr, walk.src.virt.addr,
ctx->key_enc, ctx->rounds, nbytes,
walk.iv, twk);
else
ppc_decrypt_xts(walk.dst.virt.addr, walk.src.virt.addr,
ctx->key_dec, ctx->rounds, nbytes,
walk.iv, twk);
spe_end();
twk = NULL;
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
}
return err;
}
static int ppc_xts_encrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct ppc_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
int tail = req->cryptlen % AES_BLOCK_SIZE;
int offset = req->cryptlen - tail - AES_BLOCK_SIZE;
struct skcipher_request subreq;
u8 b[2][AES_BLOCK_SIZE];
int err;
if (req->cryptlen < AES_BLOCK_SIZE)
return -EINVAL;
if (tail) {
subreq = *req;
skcipher_request_set_crypt(&subreq, req->src, req->dst,
req->cryptlen - tail, req->iv);
req = &subreq;
}
err = ppc_xts_crypt(req, true);
if (err || !tail)
return err;
scatterwalk_map_and_copy(b[0], req->dst, offset, AES_BLOCK_SIZE, 0);
memcpy(b[1], b[0], tail);
scatterwalk_map_and_copy(b[0], req->src, offset + AES_BLOCK_SIZE, tail, 0);
spe_begin();
ppc_encrypt_xts(b[0], b[0], ctx->key_enc, ctx->rounds, AES_BLOCK_SIZE,
req->iv, NULL);
spe_end();
scatterwalk_map_and_copy(b[0], req->dst, offset, AES_BLOCK_SIZE + tail, 1);
return 0;
}
static int ppc_xts_decrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct ppc_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
int tail = req->cryptlen % AES_BLOCK_SIZE;
int offset = req->cryptlen - tail - AES_BLOCK_SIZE;
struct skcipher_request subreq;
u8 b[3][AES_BLOCK_SIZE];
le128 twk;
int err;
if (req->cryptlen < AES_BLOCK_SIZE)
return -EINVAL;
if (tail) {
subreq = *req;
skcipher_request_set_crypt(&subreq, req->src, req->dst,
offset, req->iv);
req = &subreq;
}
err = ppc_xts_crypt(req, false);
if (err || !tail)
return err;
scatterwalk_map_and_copy(b[1], req->src, offset, AES_BLOCK_SIZE + tail, 0);
spe_begin();
if (!offset)
ppc_encrypt_ecb(req->iv, req->iv, ctx->key_twk, ctx->rounds,
AES_BLOCK_SIZE);
gf128mul_x_ble(&twk, (le128 *)req->iv);
ppc_decrypt_xts(b[1], b[1], ctx->key_dec, ctx->rounds, AES_BLOCK_SIZE,
(u8 *)&twk, NULL);
memcpy(b[0], b[2], tail);
memcpy(b[0] + tail, b[1] + tail, AES_BLOCK_SIZE - tail);
ppc_decrypt_xts(b[0], b[0], ctx->key_dec, ctx->rounds, AES_BLOCK_SIZE,
req->iv, NULL);
spe_end();
scatterwalk_map_and_copy(b[0], req->dst, offset, AES_BLOCK_SIZE + tail, 1);
return 0;
}
/*
* Algorithm definitions. Disabling alignment (cra_alignmask=0) was chosen
* because the e500 platform can handle unaligned reads/writes very efficently.
* This improves IPsec thoughput by another few percent. Additionally we assume
* that AES context is always aligned to at least 8 bytes because it is created
* with kmalloc() in the crypto infrastructure
*/
static struct crypto_alg aes_cipher_alg = {
.cra_name = "aes",
.cra_driver_name = "aes-ppc-spe",
.cra_priority = 300,
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = AES_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct ppc_aes_ctx),
.cra_alignmask = 0,
.cra_module = THIS_MODULE,
.cra_u = {
.cipher = {
.cia_min_keysize = AES_MIN_KEY_SIZE,
.cia_max_keysize = AES_MAX_KEY_SIZE,
.cia_setkey = ppc_aes_setkey,
.cia_encrypt = ppc_aes_encrypt,
.cia_decrypt = ppc_aes_decrypt
}
}
};
static struct skcipher_alg aes_skcipher_algs[] = {
{
.base.cra_name = "ecb(aes)",
.base.cra_driver_name = "ecb-ppc-spe",
.base.cra_priority = 300,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct ppc_aes_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.setkey = ppc_aes_setkey_skcipher,
.encrypt = ppc_ecb_encrypt,
.decrypt = ppc_ecb_decrypt,
}, {
.base.cra_name = "cbc(aes)",
.base.cra_driver_name = "cbc-ppc-spe",
.base.cra_priority = 300,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct ppc_aes_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.ivsize = AES_BLOCK_SIZE,
.setkey = ppc_aes_setkey_skcipher,
.encrypt = ppc_cbc_encrypt,
.decrypt = ppc_cbc_decrypt,
}, {
.base.cra_name = "ctr(aes)",
.base.cra_driver_name = "ctr-ppc-spe",
.base.cra_priority = 300,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct ppc_aes_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.ivsize = AES_BLOCK_SIZE,
.setkey = ppc_aes_setkey_skcipher,
.encrypt = ppc_ctr_crypt,
.decrypt = ppc_ctr_crypt,
.chunksize = AES_BLOCK_SIZE,
}, {
.base.cra_name = "xts(aes)",
.base.cra_driver_name = "xts-ppc-spe",
.base.cra_priority = 300,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct ppc_xts_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = AES_MIN_KEY_SIZE * 2,
.max_keysize = AES_MAX_KEY_SIZE * 2,
.ivsize = AES_BLOCK_SIZE,
.setkey = ppc_xts_setkey,
.encrypt = ppc_xts_encrypt,
.decrypt = ppc_xts_decrypt,
}
};
static int __init ppc_aes_mod_init(void)
{
int err;
err = crypto_register_alg(&aes_cipher_alg);
if (err)
return err;
err = crypto_register_skciphers(aes_skcipher_algs,
ARRAY_SIZE(aes_skcipher_algs));
if (err)
crypto_unregister_alg(&aes_cipher_alg);
return err;
}
static void __exit ppc_aes_mod_fini(void)
{
crypto_unregister_alg(&aes_cipher_alg);
crypto_unregister_skciphers(aes_skcipher_algs,
ARRAY_SIZE(aes_skcipher_algs));
}
module_init(ppc_aes_mod_init);
module_exit(ppc_aes_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS, SPE optimized");
MODULE_ALIAS_CRYPTO("aes");
MODULE_ALIAS_CRYPTO("ecb(aes)");
MODULE_ALIAS_CRYPTO("cbc(aes)");
MODULE_ALIAS_CRYPTO("ctr(aes)");
MODULE_ALIAS_CRYPTO("xts(aes)");
MODULE_ALIAS_CRYPTO("aes-ppc-spe");