arch/arm/crypto/chacha-glue.c - linux - Git at Google

 // 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, unsigned int nbytes);
 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) {
 		unsigned int l = min(bytes, CHACHA_BLOCK_SIZE * 4U);

 		chacha_4block_xor_neon(state, dst, src, nrounds, l);
 		bytes -= l;
 		src += l;
 		dst += l;
 		state[12] += DIV_ROUND_UP(l, CHACHA_BLOCK_SIZE);
 	}
 	if (bytes) {
 		const u8 *s = src;
 		u8 *d = dst;

 		if (bytes != CHACHA_BLOCK_SIZE)
 			s = d = memcpy(buf, src, bytes);
 		chacha_block_xor_neon(state, d, s, nrounds);
 		if (d != dst)
 			memcpy(dst, buf, bytes);
 		state[12]++;
 	}
 }

 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
	// 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, unsigned int nbytes);
	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) {
	unsigned int l = min(bytes, CHACHA_BLOCK_SIZE * 4U);

	chacha_4block_xor_neon(state, dst, src, nrounds, l);
	bytes -= l;
	src += l;
	dst += l;
	state[12] += DIV_ROUND_UP(l, CHACHA_BLOCK_SIZE);
	}
	if (bytes) {
	const u8 *s = src;
	u8 *d = dst;

	if (bytes != CHACHA_BLOCK_SIZE)
	s = d = memcpy(buf, src, bytes);
	chacha_block_xor_neon(state, d, s, nrounds);
	if (d != dst)
	memcpy(dst, buf, bytes);
	state[12]++;
	}
	}

	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