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// SPDX-License-Identifier: GPL-2.0
/*
* ARM NEON accelerated ChaCha and XChaCha stream ciphers,
* including ChaCha20 (RFC7539)
*
* Copyright (C) 2016-2019 Linaro, Ltd. <ard.biesheuvel@linaro.org>
* Copyright (C) 2015 Martin Willi
*/
#include <crypto/algapi.h>
#include <crypto/internal/chacha.h>
#include <crypto/internal/simd.h>
#include <crypto/internal/skcipher.h>
#include <linux/jump_label.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/cputype.h>
#include <asm/hwcap.h>
#include <asm/neon.h>
#include <asm/simd.h>
asmlinkage void chacha_block_xor_neon(const u32 *state, u8 *dst, const u8 *src,
int nrounds);
asmlinkage void chacha_4block_xor_neon(const u32 *state, u8 *dst, const u8 *src,
int nrounds);
asmlinkage void hchacha_block_arm(const u32 *state, u32 *out, int nrounds);
asmlinkage void hchacha_block_neon(const u32 *state, u32 *out, int nrounds);
asmlinkage void chacha_doarm(u8 *dst, const u8 *src, unsigned int bytes,
const u32 *state, int nrounds);
static __ro_after_init DEFINE_STATIC_KEY_FALSE(use_neon);
static inline bool neon_usable(void)
{
return static_branch_likely(&use_neon) && crypto_simd_usable();
}
static void chacha_doneon(u32 *state, u8 *dst, const u8 *src,
unsigned int bytes, int nrounds)
{
u8 buf[CHACHA_BLOCK_SIZE];
while (bytes >= CHACHA_BLOCK_SIZE * 4) {
chacha_4block_xor_neon(state, dst, src, nrounds);
bytes -= CHACHA_BLOCK_SIZE * 4;
src += CHACHA_BLOCK_SIZE * 4;
dst += CHACHA_BLOCK_SIZE * 4;
state[12] += 4;
}
while (bytes >= CHACHA_BLOCK_SIZE) {
chacha_block_xor_neon(state, dst, src, nrounds);
bytes -= CHACHA_BLOCK_SIZE;
src += CHACHA_BLOCK_SIZE;
dst += CHACHA_BLOCK_SIZE;
state[12]++;
}
if (bytes) {
memcpy(buf, src, bytes);
chacha_block_xor_neon(state, buf, buf, nrounds);
memcpy(dst, buf, bytes);
}
}
void hchacha_block_arch(const u32 *state, u32 *stream, int nrounds)
{
if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon_usable()) {
hchacha_block_arm(state, stream, nrounds);
} else {
kernel_neon_begin();
hchacha_block_neon(state, stream, nrounds);
kernel_neon_end();
}
}
EXPORT_SYMBOL(hchacha_block_arch);
void chacha_init_arch(u32 *state, const u32 *key, const u8 *iv)
{
chacha_init_generic(state, key, iv);
}
EXPORT_SYMBOL(chacha_init_arch);
void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
int nrounds)
{
if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon_usable() ||
bytes <= CHACHA_BLOCK_SIZE) {
chacha_doarm(dst, src, bytes, state, nrounds);
state[12] += DIV_ROUND_UP(bytes, CHACHA_BLOCK_SIZE);
return;
}
do {
unsigned int todo = min_t(unsigned int, bytes, SZ_4K);
kernel_neon_begin();
chacha_doneon(state, dst, src, todo, nrounds);
kernel_neon_end();
bytes -= todo;
src += todo;
dst += todo;
} while (bytes);
}
EXPORT_SYMBOL(chacha_crypt_arch);
static int chacha_stream_xor(struct skcipher_request *req,
const struct chacha_ctx *ctx, const u8 *iv,
bool neon)
{
struct skcipher_walk walk;
u32 state[16];
int err;
err = skcipher_walk_virt(&walk, req, false);
chacha_init_generic(state, ctx->key, iv);
while (walk.nbytes > 0) {
unsigned int nbytes = walk.nbytes;
if (nbytes < walk.total)
nbytes = round_down(nbytes, walk.stride);
if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon) {
chacha_doarm(walk.dst.virt.addr, walk.src.virt.addr,
nbytes, state, ctx->nrounds);
state[12] += DIV_ROUND_UP(nbytes, CHACHA_BLOCK_SIZE);
} else {
kernel_neon_begin();
chacha_doneon(state, walk.dst.virt.addr,
walk.src.virt.addr, nbytes, ctx->nrounds);
kernel_neon_end();
}
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
}
return err;
}
static int do_chacha(struct skcipher_request *req, bool neon)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
return chacha_stream_xor(req, ctx, req->iv, neon);
}
static int chacha_arm(struct skcipher_request *req)
{
return do_chacha(req, false);
}
static int chacha_neon(struct skcipher_request *req)
{
return do_chacha(req, neon_usable());
}
static int do_xchacha(struct skcipher_request *req, bool neon)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
struct chacha_ctx subctx;
u32 state[16];
u8 real_iv[16];
chacha_init_generic(state, ctx->key, req->iv);
if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon) {
hchacha_block_arm(state, subctx.key, ctx->nrounds);
} else {
kernel_neon_begin();
hchacha_block_neon(state, subctx.key, ctx->nrounds);
kernel_neon_end();
}
subctx.nrounds = ctx->nrounds;
memcpy(&real_iv[0], req->iv + 24, 8);
memcpy(&real_iv[8], req->iv + 16, 8);
return chacha_stream_xor(req, &subctx, real_iv, neon);
}
static int xchacha_arm(struct skcipher_request *req)
{
return do_xchacha(req, false);
}
static int xchacha_neon(struct skcipher_request *req)
{
return do_xchacha(req, neon_usable());
}
static struct skcipher_alg arm_algs[] = {
{
.base.cra_name = "chacha20",
.base.cra_driver_name = "chacha20-arm",
.base.cra_priority = 200,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = CHACHA_KEY_SIZE,
.max_keysize = CHACHA_KEY_SIZE,
.ivsize = CHACHA_IV_SIZE,
.chunksize = CHACHA_BLOCK_SIZE,
.setkey = chacha20_setkey,
.encrypt = chacha_arm,
.decrypt = chacha_arm,
}, {
.base.cra_name = "xchacha20",
.base.cra_driver_name = "xchacha20-arm",
.base.cra_priority = 200,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = CHACHA_KEY_SIZE,
.max_keysize = CHACHA_KEY_SIZE,
.ivsize = XCHACHA_IV_SIZE,
.chunksize = CHACHA_BLOCK_SIZE,
.setkey = chacha20_setkey,
.encrypt = xchacha_arm,
.decrypt = xchacha_arm,
}, {
.base.cra_name = "xchacha12",
.base.cra_driver_name = "xchacha12-arm",
.base.cra_priority = 200,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = CHACHA_KEY_SIZE,
.max_keysize = CHACHA_KEY_SIZE,
.ivsize = XCHACHA_IV_SIZE,
.chunksize = CHACHA_BLOCK_SIZE,
.setkey = chacha12_setkey,
.encrypt = xchacha_arm,
.decrypt = xchacha_arm,
},
};
static struct skcipher_alg neon_algs[] = {
{
.base.cra_name = "chacha20",
.base.cra_driver_name = "chacha20-neon",
.base.cra_priority = 300,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = CHACHA_KEY_SIZE,
.max_keysize = CHACHA_KEY_SIZE,
.ivsize = CHACHA_IV_SIZE,
.chunksize = CHACHA_BLOCK_SIZE,
.walksize = 4 * CHACHA_BLOCK_SIZE,
.setkey = chacha20_setkey,
.encrypt = chacha_neon,
.decrypt = chacha_neon,
}, {
.base.cra_name = "xchacha20",
.base.cra_driver_name = "xchacha20-neon",
.base.cra_priority = 300,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = CHACHA_KEY_SIZE,
.max_keysize = CHACHA_KEY_SIZE,
.ivsize = XCHACHA_IV_SIZE,
.chunksize = CHACHA_BLOCK_SIZE,
.walksize = 4 * CHACHA_BLOCK_SIZE,
.setkey = chacha20_setkey,
.encrypt = xchacha_neon,
.decrypt = xchacha_neon,
}, {
.base.cra_name = "xchacha12",
.base.cra_driver_name = "xchacha12-neon",
.base.cra_priority = 300,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = CHACHA_KEY_SIZE,
.max_keysize = CHACHA_KEY_SIZE,
.ivsize = XCHACHA_IV_SIZE,
.chunksize = CHACHA_BLOCK_SIZE,
.walksize = 4 * CHACHA_BLOCK_SIZE,
.setkey = chacha12_setkey,
.encrypt = xchacha_neon,
.decrypt = xchacha_neon,
}
};
static int __init chacha_simd_mod_init(void)
{
int err = 0;
if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER)) {
err = crypto_register_skciphers(arm_algs, ARRAY_SIZE(arm_algs));
if (err)
return err;
}
if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && (elf_hwcap & HWCAP_NEON)) {
int i;
switch (read_cpuid_part()) {
case ARM_CPU_PART_CORTEX_A7:
case ARM_CPU_PART_CORTEX_A5:
/*
* The Cortex-A7 and Cortex-A5 do not perform well with
* the NEON implementation but do incredibly with the
* scalar one and use less power.
*/
for (i = 0; i < ARRAY_SIZE(neon_algs); i++)
neon_algs[i].base.cra_priority = 0;
break;
default:
static_branch_enable(&use_neon);
}
if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER)) {
err = crypto_register_skciphers(neon_algs, ARRAY_SIZE(neon_algs));
if (err)
crypto_unregister_skciphers(arm_algs, ARRAY_SIZE(arm_algs));
}
}
return err;
}
static void __exit chacha_simd_mod_fini(void)
{
if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER)) {
crypto_unregister_skciphers(arm_algs, ARRAY_SIZE(arm_algs));
if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && (elf_hwcap & HWCAP_NEON))
crypto_unregister_skciphers(neon_algs, ARRAY_SIZE(neon_algs));
}
}
module_init(chacha_simd_mod_init);
module_exit(chacha_simd_mod_fini);
MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (scalar and NEON accelerated)");
MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_CRYPTO("chacha20");
MODULE_ALIAS_CRYPTO("chacha20-arm");
MODULE_ALIAS_CRYPTO("xchacha20");
MODULE_ALIAS_CRYPTO("xchacha20-arm");
MODULE_ALIAS_CRYPTO("xchacha12");
MODULE_ALIAS_CRYPTO("xchacha12-arm");
#ifdef CONFIG_KERNEL_MODE_NEON
MODULE_ALIAS_CRYPTO("chacha20-neon");
MODULE_ALIAS_CRYPTO("xchacha20-neon");
MODULE_ALIAS_CRYPTO("xchacha12-neon");
#endif