Commit ceba0eda authored by Eric Biggers's avatar Eric Biggers Committed by Herbert Xu
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crypto: riscv/chacha - implement library instead of skcipher 



Currently the RISC-V optimized ChaCha20 is only wired up to the
crypto_skcipher API, which makes it unavailable to users of the library
API.  The crypto_skcipher API for ChaCha20 is going to change to be
implemented on top of the library API, so the library API needs to be
supported.  And of course it's needed anyway to serve the library users.

Therefore, change the RISC-V ChaCha20 code to implement the library API
instead of the crypto_skcipher API.

The library functions take the ChaCha state matrix directly (instead of
key and IV) and support both ChaCha20 and ChaCha12.  To make the RISC-V
code work properly for that, change the assembly code to take the state
matrix directly and add a nrounds parameter.

Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 570ef50a

arch/riscv/crypto/Kconfig

+4 −7
Original line number Diff line number Diff line
@@ -19,14 +19,11 @@ config CRYPTO_AES_RISCV64 
	  - Zvkg vector crypto extension (XTS)



config CRYPTO_CHACHA_RISCV64

	tristate "Ciphers: ChaCha"

	tristate

	depends on 64BIT && RISCV_ISA_V && TOOLCHAIN_HAS_VECTOR_CRYPTO

	select CRYPTO_SKCIPHER

	help

	  Length-preserving ciphers: ChaCha20 stream cipher algorithm



	  Architecture: riscv64 using:

	  - Zvkb vector crypto extension

	select CRYPTO_ARCH_HAVE_LIB_CHACHA

	select CRYPTO_LIB_CHACHA_GENERIC

	default CRYPTO_LIB_CHACHA_INTERNAL



config CRYPTO_GHASH_RISCV64

	tristate "Hash functions: GHASH"

arch/riscv/crypto/chacha-riscv64-glue.c

+34 −72
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * ChaCha20 using the RISC-V vector crypto extensions

 * ChaCha stream cipher (RISC-V optimized)

 *

 * Copyright (C) 2023 SiFive, Inc.

 * Author: Jerry Shih <jerry.shih@sifive.com>
@@ -8,94 +8,56 @@ 


#include <asm/simd.h>

#include <asm/vector.h>

#include <crypto/internal/chacha.h>

#include <crypto/internal/skcipher.h>

#include <crypto/chacha.h>

#include <crypto/internal/simd.h>

#include <linux/linkage.h>

#include <linux/module.h>



asmlinkage void chacha20_zvkb(const u32 key[8], const u8 *in, u8 *out,

			      size_t len, const u32 iv[4]);

static __ro_after_init DEFINE_STATIC_KEY_FALSE(use_zvkb);



static int riscv64_chacha20_crypt(struct skcipher_request *req)

asmlinkage void chacha_zvkb(u32 state[16], const u8 *in, u8 *out,

			    size_t nblocks, int nrounds);



void hchacha_block_arch(const u32 *state, u32 *out, int nrounds)

{

	hchacha_block_generic(state, out, nrounds);

}

EXPORT_SYMBOL(hchacha_block_arch);



void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,

		       int nrounds)

{

	u32 iv[CHACHA_IV_SIZE / sizeof(u32)];

	u8 block_buffer[CHACHA_BLOCK_SIZE];

	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);

	const struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);

	struct skcipher_walk walk;

	unsigned int nbytes;

	unsigned int tail_bytes;

	int err;

	unsigned int full_blocks = bytes / CHACHA_BLOCK_SIZE;

	unsigned int tail_bytes = bytes % CHACHA_BLOCK_SIZE;



	iv[0] = get_unaligned_le32(req->iv);

	iv[1] = get_unaligned_le32(req->iv + 4);

	iv[2] = get_unaligned_le32(req->iv + 8);

	iv[3] = get_unaligned_le32(req->iv + 12);

	if (!static_branch_likely(&use_zvkb) || !crypto_simd_usable())

		return chacha_crypt_generic(state, dst, src, bytes, nrounds);



	err = skcipher_walk_virt(&walk, req, false);

	while (walk.nbytes) {

		nbytes = walk.nbytes & ~(CHACHA_BLOCK_SIZE - 1);

		tail_bytes = walk.nbytes & (CHACHA_BLOCK_SIZE - 1);

	kernel_vector_begin();

		if (nbytes) {

			chacha20_zvkb(ctx->key, walk.src.virt.addr,

				      walk.dst.virt.addr, nbytes, iv);

			iv[0] += nbytes / CHACHA_BLOCK_SIZE;

	if (full_blocks) {

		chacha_zvkb(state, src, dst, full_blocks, nrounds);

		src += full_blocks * CHACHA_BLOCK_SIZE;

		dst += full_blocks * CHACHA_BLOCK_SIZE;

	}

		if (walk.nbytes == walk.total && tail_bytes > 0) {

			memcpy(block_buffer, walk.src.virt.addr + nbytes,

			       tail_bytes);

			chacha20_zvkb(ctx->key, block_buffer, block_buffer,

				      CHACHA_BLOCK_SIZE, iv);

			memcpy(walk.dst.virt.addr + nbytes, block_buffer,

			       tail_bytes);

			tail_bytes = 0;

	if (tail_bytes) {

		memcpy(block_buffer, src, tail_bytes);

		chacha_zvkb(state, block_buffer, block_buffer, 1, nrounds);

		memcpy(dst, block_buffer, tail_bytes);

	}

	kernel_vector_end();



		err = skcipher_walk_done(&walk, tail_bytes);

	}



	return err;

}



static struct skcipher_alg riscv64_chacha_alg = {

	.setkey = chacha20_setkey,

	.encrypt = riscv64_chacha20_crypt,

	.decrypt = riscv64_chacha20_crypt,

	.min_keysize = CHACHA_KEY_SIZE,

	.max_keysize = CHACHA_KEY_SIZE,

	.ivsize = CHACHA_IV_SIZE,

	.chunksize = CHACHA_BLOCK_SIZE,

	.walksize = 4 * CHACHA_BLOCK_SIZE,

	.base = {

		.cra_blocksize = 1,

		.cra_ctxsize = sizeof(struct chacha_ctx),

		.cra_priority = 300,

		.cra_name = "chacha20",

		.cra_driver_name = "chacha20-riscv64-zvkb",

		.cra_module = THIS_MODULE,

	},

};

EXPORT_SYMBOL(chacha_crypt_arch);



static int __init riscv64_chacha_mod_init(void)

{

	if (riscv_isa_extension_available(NULL, ZVKB) &&

	    riscv_vector_vlen() >= 128)

		return crypto_register_skcipher(&riscv64_chacha_alg);



	return -ENODEV;

}



static void __exit riscv64_chacha_mod_exit(void)

{

	crypto_unregister_skcipher(&riscv64_chacha_alg);

		static_branch_enable(&use_zvkb);

	return 0;

}



module_init(riscv64_chacha_mod_init);

module_exit(riscv64_chacha_mod_exit);



MODULE_DESCRIPTION("ChaCha20 (RISC-V accelerated)");

MODULE_DESCRIPTION("ChaCha stream cipher (RISC-V optimized)");

MODULE_AUTHOR("Jerry Shih <jerry.shih@sifive.com>");

MODULE_LICENSE("GPL");
 
MODULE_ALIAS_CRYPTO("chacha20");

arch/riscv/crypto/chacha-riscv64-zvkb.S

+37 −34
Original line number Diff line number Diff line
@@ -46,11 +46,11 @@ 
.text

.option arch, +zvkb



#define KEYP		a0

#define STATEP		a0

#define INP		a1

#define OUTP		a2

#define LEN		a3

#define IVP		a4

#define NBLOCKS		a3

#define NROUNDS		a4



#define CONSTS0		a5

#define CONSTS1		a6
@@ -59,7 +59,7 @@ 
#define TMP		t1

#define VL		t2

#define STRIDE		t3

#define NROUNDS		t4

#define ROUND_CTR	t4

#define KEY0		s0

#define KEY1		s1

#define KEY2		s2
@@ -132,14 +132,16 @@ 
	vror.vi		\b3, \b3, 32 - 7

.endm



// void chacha20_zvkb(const u32 key[8], const u8 *in, u8 *out, size_t len,

//		      const u32 iv[4]);

// void chacha_zvkb(u32 state[16], const u8 *in, u8 *out, size_t nblocks,

//		    int nrounds);

//

// |len| must be nonzero and a multiple of 64 (CHACHA_BLOCK_SIZE).

// The counter is treated as 32-bit, following the RFC7539 convention.

SYM_FUNC_START(chacha20_zvkb)

	srli		LEN, LEN, 6	// Bytes to blocks



// |nblocks| is the number of 64-byte blocks to process, and must be nonzero.

//

// |state| gives the ChaCha state matrix, including the 32-bit counter in

// state[12] following the RFC7539 convention; note that this differs from the

// original Salsa20 paper which uses a 64-bit counter in state[12..13].  The

// updated 32-bit counter is written back to state[12] before returning.

SYM_FUNC_START(chacha_zvkb)

	addi		sp, sp, -96

	sd		s0, 0(sp)

	sd		s1, 8(sp)
@@ -157,26 +159,26 @@ SYM_FUNC_START(chacha20_zvkb) 
	li		STRIDE, 64



	// Set up the initial state matrix in scalar registers.

	li		CONSTS0, 0x61707865	// "expa" little endian

	li		CONSTS1, 0x3320646e	// "nd 3" little endian

	li		CONSTS2, 0x79622d32	// "2-by" little endian

	li		CONSTS3, 0x6b206574	// "te k" little endian

	lw		KEY0, 0(KEYP)

	lw		KEY1, 4(KEYP)

	lw		KEY2, 8(KEYP)

	lw		KEY3, 12(KEYP)

	lw		KEY4, 16(KEYP)

	lw		KEY5, 20(KEYP)

	lw		KEY6, 24(KEYP)

	lw		KEY7, 28(KEYP)

	lw		COUNTER, 0(IVP)

	lw		NONCE0, 4(IVP)

	lw		NONCE1, 8(IVP)

	lw		NONCE2, 12(IVP)

	lw		CONSTS0, 0(STATEP)

	lw		CONSTS1, 4(STATEP)

	lw		CONSTS2, 8(STATEP)

	lw		CONSTS3, 12(STATEP)

	lw		KEY0, 16(STATEP)

	lw		KEY1, 20(STATEP)

	lw		KEY2, 24(STATEP)

	lw		KEY3, 28(STATEP)

	lw		KEY4, 32(STATEP)

	lw		KEY5, 36(STATEP)

	lw		KEY6, 40(STATEP)

	lw		KEY7, 44(STATEP)

	lw		COUNTER, 48(STATEP)

	lw		NONCE0, 52(STATEP)

	lw		NONCE1, 56(STATEP)

	lw		NONCE2, 60(STATEP)



.Lblock_loop:

	// Set vl to the number of blocks to process in this iteration.

	vsetvli		VL, LEN, e32, m1, ta, ma

	vsetvli		VL, NBLOCKS, e32, m1, ta, ma



	// Set up the initial state matrix for the next VL blocks in v0-v15.

	// v{i} holds the i'th 32-bit word of the state matrix for all blocks.
@@ -203,16 +205,16 @@ SYM_FUNC_START(chacha20_zvkb) 
	// v{16+i} holds the i'th 32-bit word for all blocks.

	vlsseg8e32.v	v16, (INP), STRIDE



	li		NROUNDS, 20

	mv		ROUND_CTR, NROUNDS

.Lnext_doubleround:

	addi		NROUNDS, NROUNDS, -2

	addi		ROUND_CTR, ROUND_CTR, -2

	// column round

	chacha_round	v0, v4, v8, v12, v1, v5, v9, v13, \

			v2, v6, v10, v14, v3, v7, v11, v15

	// diagonal round

	chacha_round	v0, v5, v10, v15, v1, v6, v11, v12, \

			v2, v7, v8, v13, v3, v4, v9, v14

	bnez		NROUNDS, .Lnext_doubleround

	bnez		ROUND_CTR, .Lnext_doubleround



	// Load the second half of the input data for each block into v24-v31.

	// v{24+i} holds the {8+i}'th 32-bit word for all blocks.
@@ -271,12 +273,13 @@ SYM_FUNC_START(chacha20_zvkb) 
	// Update the counter, the remaining number of blocks, and the input and

	// output pointers according to the number of blocks processed (VL).

	add		COUNTER, COUNTER, VL

	sub		LEN, LEN, VL

	sub		NBLOCKS, NBLOCKS, VL

	slli		TMP, VL, 6

	add		OUTP, OUTP, TMP

	add		INP, INP, TMP

	bnez		LEN, .Lblock_loop

	bnez		NBLOCKS, .Lblock_loop



	sw		COUNTER, 48(STATEP)

	ld		s0, 0(sp)

	ld		s1, 8(sp)

	ld		s2, 16(sp)
@@ -291,4 +294,4 @@ SYM_FUNC_START(chacha20_zvkb) 
	ld		s11, 88(sp)

	addi		sp, sp, 96

	ret

SYM_FUNC_END(chacha20_zvkb)
 
SYM_FUNC_END(chacha_zvkb)