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Commit 95a34b77 authored by Eric Biggers's avatar Eric Biggers Committed by Herbert Xu
Browse files

crypto: arm64/chacha20 - refactor to allow varying number of rounds 



In preparation for adding XChaCha12 support, rename/refactor the ARM64
NEON implementation of ChaCha20 to support different numbers of rounds.

Reviewed-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent cc7cf991

arch/arm64/crypto/Makefile

+2 −2
Original line number Diff line number Diff line
@@ -50,8 +50,8 @@ sha256-arm64-y := sha256-glue.o sha256-core.o 
obj-$(CONFIG_CRYPTO_SHA512_ARM64) += sha512-arm64.o

sha512-arm64-y := sha512-glue.o sha512-core.o



obj-$(CONFIG_CRYPTO_CHACHA20_NEON) += chacha20-neon.o

chacha20-neon-y := chacha20-neon-core.o chacha20-neon-glue.o

obj-$(CONFIG_CRYPTO_CHACHA20_NEON) += chacha-neon.o

chacha-neon-y := chacha-neon-core.o chacha-neon-glue.o



obj-$(CONFIG_CRYPTO_NHPOLY1305_NEON) += nhpoly1305-neon.o

nhpoly1305-neon-y := nh-neon-core.o nhpoly1305-neon-glue.o

arch/arm64/crypto/chacha20-neon-core.S→arch/arm64/crypto/chacha-neon-core.S

+24 −21
Original line number Diff line number Diff line 
/*

 * ChaCha20 256-bit cipher algorithm, RFC7539, arm64 NEON functions

 * ChaCha/XChaCha NEON helper functions

 *

 * Copyright (C) 2016 Linaro, Ltd. <ard.biesheuvel@linaro.org>

 *
@@ -24,17 +24,18 @@ 
	.align		6



/*

 * chacha20_permute - permute one block

 * chacha_permute - permute one block

 *

 * Permute one 64-byte block where the state matrix is stored in the four NEON

 * registers v0-v3.  It performs matrix operations on four words in parallel,

 * but requires shuffling to rearrange the words after each round.

 *

 * Clobbers: x3, x10, v4, v12

 * The round count is given in w3.

 *

 * Clobbers: w3, x10, v4, v12

 */

chacha20_permute:

chacha_permute:



	mov		x3, #10

	adr		x10, ROT8

	ld1		{v12.4s}, [x10]
@@ -97,16 +98,17 @@ chacha20_permute: 
	// x3 = shuffle32(x3, MASK(0, 3, 2, 1))

	ext		v3.16b, v3.16b, v3.16b, #4



	subs		x3, x3, #1

	subs		w3, w3, #2

	b.ne		.Ldoubleround



	ret

ENDPROC(chacha20_permute)

ENDPROC(chacha_permute)



ENTRY(chacha20_block_xor_neon)

ENTRY(chacha_block_xor_neon)

	// x0: Input state matrix, s

	// x1: 1 data block output, o

	// x2: 1 data block input, i

	// w3: nrounds



	stp		x29, x30, [sp, #-16]!

	mov		x29, sp
@@ -115,7 +117,7 @@ ENTRY(chacha20_block_xor_neon) 
	ld1		{v0.4s-v3.4s}, [x0]

	ld1		{v8.4s-v11.4s}, [x0]



	bl		chacha20_permute

	bl		chacha_permute



	ld1		{v4.16b-v7.16b}, [x2]
@@ -139,42 +141,45 @@ ENTRY(chacha20_block_xor_neon) 


	ldp		x29, x30, [sp], #16

	ret

ENDPROC(chacha20_block_xor_neon)

ENDPROC(chacha_block_xor_neon)



ENTRY(hchacha20_block_neon)

ENTRY(hchacha_block_neon)

	// x0: Input state matrix, s

	// x1: output (8 32-bit words)

	// w2: nrounds



	stp		x29, x30, [sp, #-16]!

	mov		x29, sp



	ld1		{v0.4s-v3.4s}, [x0]



	bl		chacha20_permute

	mov		w3, w2

	bl		chacha_permute



	st1		{v0.16b}, [x1], #16

	st1		{v3.16b}, [x1]



	ldp		x29, x30, [sp], #16

	ret

ENDPROC(hchacha20_block_neon)

ENDPROC(hchacha_block_neon)



	.align		6

ENTRY(chacha20_4block_xor_neon)

ENTRY(chacha_4block_xor_neon)

	// x0: Input state matrix, s

	// x1: 4 data blocks output, o

	// x2: 4 data blocks input, i

	// w3: nrounds



	//

	// This function encrypts four consecutive ChaCha20 blocks by loading

	// This function encrypts four consecutive ChaCha blocks by loading

	// the state matrix in NEON registers four times. The algorithm performs

	// each operation on the corresponding word of each state matrix, hence

	// requires no word shuffling. For final XORing step we transpose the

	// matrix by interleaving 32- and then 64-bit words, which allows us to

	// do XOR in NEON registers.

	//

	adr		x3, CTRINC		// ... and ROT8

	ld1		{v30.4s-v31.4s}, [x3]

	adr		x9, CTRINC		// ... and ROT8

	ld1		{v30.4s-v31.4s}, [x9]



	// x0..15[0-3] = s0..3[0..3]

	mov		x4, x0
@@ -186,8 +191,6 @@ ENTRY(chacha20_4block_xor_neon) 
	// x12 += counter values 0-3

	add		v12.4s, v12.4s, v30.4s



	mov		x3, #10



.Ldoubleround4:

	// x0 += x4, x12 = rotl32(x12 ^ x0, 16)

	// x1 += x5, x13 = rotl32(x13 ^ x1, 16)
@@ -361,7 +364,7 @@ ENTRY(chacha20_4block_xor_neon) 
	sri		v7.4s, v18.4s, #25

	sri		v4.4s, v19.4s, #25



	subs		x3, x3, #1

	subs		w3, w3, #2

	b.ne		.Ldoubleround4



	ld4r		{v16.4s-v19.4s}, [x0], #16
@@ -475,7 +478,7 @@ ENTRY(chacha20_4block_xor_neon) 
	st1		{v28.16b-v31.16b}, [x1]



	ret

ENDPROC(chacha20_4block_xor_neon)

ENDPROC(chacha_4block_xor_neon)



CTRINC:	.word		0, 1, 2, 3

ROT8:	.word		0x02010003, 0x06050407, 0x0a09080b, 0x0e0d0c0f

arch/arm64/crypto/chacha20-neon-glue.c→arch/arm64/crypto/chacha-neon-glue.c

+31 −26
Original line number Diff line number Diff line 
/*

 * ChaCha20 256-bit cipher algorithm, RFC7539, arm64 NEON functions

 * ARM NEON accelerated ChaCha and XChaCha stream ciphers,

 * including ChaCha20 (RFC7539)

 *

 * Copyright (C) 2016 - 2017 Linaro, Ltd. <ard.biesheuvel@linaro.org>

 *
@@ -28,18 +29,20 @@ 
#include <asm/neon.h>

#include <asm/simd.h>



asmlinkage void chacha20_block_xor_neon(u32 *state, u8 *dst, const u8 *src);

asmlinkage void chacha20_4block_xor_neon(u32 *state, u8 *dst, const u8 *src);

asmlinkage void hchacha20_block_neon(const u32 *state, u32 *out);

asmlinkage void chacha_block_xor_neon(u32 *state, u8 *dst, const u8 *src,

				      int nrounds);

asmlinkage void chacha_4block_xor_neon(u32 *state, u8 *dst, const u8 *src,

				       int nrounds);

asmlinkage void hchacha_block_neon(const u32 *state, u32 *out, int nrounds);



static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,

			    unsigned int bytes)

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) {

		kernel_neon_begin();

		chacha20_4block_xor_neon(state, dst, src);

		chacha_4block_xor_neon(state, dst, src, nrounds);

		kernel_neon_end();

		bytes -= CHACHA_BLOCK_SIZE * 4;

		src += CHACHA_BLOCK_SIZE * 4;
@@ -52,7 +55,7 @@ static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src, 


	kernel_neon_begin();

	while (bytes >= CHACHA_BLOCK_SIZE) {

		chacha20_block_xor_neon(state, dst, src);

		chacha_block_xor_neon(state, dst, src, nrounds);

		bytes -= CHACHA_BLOCK_SIZE;

		src += CHACHA_BLOCK_SIZE;

		dst += CHACHA_BLOCK_SIZE;
@@ -60,13 +63,13 @@ static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src, 
	}

	if (bytes) {

		memcpy(buf, src, bytes);

		chacha20_block_xor_neon(state, buf, buf);

		chacha_block_xor_neon(state, buf, buf, nrounds);

		memcpy(dst, buf, bytes);

	}

	kernel_neon_end();

}



static int chacha20_neon_stream_xor(struct skcipher_request *req,

static int chacha_neon_stream_xor(struct skcipher_request *req,

				  struct chacha_ctx *ctx, u8 *iv)

{

	struct skcipher_walk walk;
@@ -83,15 +86,15 @@ static int chacha20_neon_stream_xor(struct skcipher_request *req, 
		if (nbytes < walk.total)

			nbytes = round_down(nbytes, walk.stride);



		chacha20_doneon(state, walk.dst.virt.addr, walk.src.virt.addr,

				nbytes);

		chacha_doneon(state, walk.dst.virt.addr, walk.src.virt.addr,

			      nbytes, ctx->nrounds);

		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);

	}



	return err;

}



static int chacha20_neon(struct skcipher_request *req)

static int chacha_neon(struct skcipher_request *req)

{

	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);

	struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
@@ -99,10 +102,10 @@ static int chacha20_neon(struct skcipher_request *req) 
	if (req->cryptlen <= CHACHA_BLOCK_SIZE || !may_use_simd())

		return crypto_chacha_crypt(req);



	return chacha20_neon_stream_xor(req, ctx, req->iv);

	return chacha_neon_stream_xor(req, ctx, req->iv);

}



static int xchacha20_neon(struct skcipher_request *req)

static int xchacha_neon(struct skcipher_request *req)

{

	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);

	struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
@@ -116,12 +119,13 @@ static int xchacha20_neon(struct skcipher_request *req) 
	crypto_chacha_init(state, ctx, req->iv);



	kernel_neon_begin();

	hchacha20_block_neon(state, subctx.key);

	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 chacha20_neon_stream_xor(req, &subctx, real_iv);

	return chacha_neon_stream_xor(req, &subctx, real_iv);

}



static struct skcipher_alg algs[] = {
@@ -139,8 +143,8 @@ static struct skcipher_alg algs[] = { 
		.chunksize		= CHACHA_BLOCK_SIZE,

		.walksize		= 4 * CHACHA_BLOCK_SIZE,

		.setkey			= crypto_chacha20_setkey,

		.encrypt		= chacha20_neon,

		.decrypt		= chacha20_neon,

		.encrypt		= chacha_neon,

		.decrypt		= chacha_neon,

	}, {

		.base.cra_name		= "xchacha20",

		.base.cra_driver_name	= "xchacha20-neon",
@@ -155,12 +159,12 @@ static struct skcipher_alg algs[] = { 
		.chunksize		= CHACHA_BLOCK_SIZE,

		.walksize		= 4 * CHACHA_BLOCK_SIZE,

		.setkey			= crypto_chacha20_setkey,

		.encrypt		= xchacha20_neon,

		.decrypt		= xchacha20_neon,

		.encrypt		= xchacha_neon,

		.decrypt		= xchacha_neon,

	}

};



static int __init chacha20_simd_mod_init(void)

static int __init chacha_simd_mod_init(void)

{

	if (!(elf_hwcap & HWCAP_ASIMD))

		return -ENODEV;
@@ -168,14 +172,15 @@ static int __init chacha20_simd_mod_init(void) 
	return crypto_register_skciphers(algs, ARRAY_SIZE(algs));

}



static void __exit chacha20_simd_mod_fini(void)

static void __exit chacha_simd_mod_fini(void)

{

	crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));

}



module_init(chacha20_simd_mod_init);

module_exit(chacha20_simd_mod_fini);

module_init(chacha_simd_mod_init);

module_exit(chacha_simd_mod_fini);



MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (NEON accelerated)");

MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");

MODULE_LICENSE("GPL v2");

MODULE_ALIAS_CRYPTO("chacha20");