chacha.h

 1/* SPDX-License-Identifier: GPL-2.0-only */
 2/*
 3 * ChaCha stream cipher (RISC-V optimized)
 4 *
 5 * Copyright (C) 2023 SiFive, Inc.
 6 * Author: Jerry Shih <jerry.shih@sifive.com>
 7 */
 8
 9#include <asm/simd.h>
10#include <asm/vector.h>
11#include <crypto/internal/simd.h>
12#include <linux/linkage.h>
13
14static __ro_after_init DEFINE_STATIC_KEY_FALSE(use_zvkb);
15
16asmlinkage void chacha_zvkb(struct chacha_state *state, const u8 *in, u8 *out,
17			    size_t nblocks, int nrounds);
18
19#define hchacha_block_arch hchacha_block_generic /* not implemented yet */
20
21static void chacha_crypt_arch(struct chacha_state *state, u8 *dst,
22			      const u8 *src, unsigned int bytes, int nrounds)
23{
24	u8 block_buffer[CHACHA_BLOCK_SIZE];
25	unsigned int full_blocks = bytes / CHACHA_BLOCK_SIZE;
26	unsigned int tail_bytes = bytes % CHACHA_BLOCK_SIZE;
27
28	if (!static_branch_likely(&use_zvkb) || !crypto_simd_usable())
29		return chacha_crypt_generic(state, dst, src, bytes, nrounds);
30
31	kernel_vector_begin();
32	if (full_blocks) {
33		chacha_zvkb(state, src, dst, full_blocks, nrounds);
34		src += full_blocks * CHACHA_BLOCK_SIZE;
35		dst += full_blocks * CHACHA_BLOCK_SIZE;
36	}
37	if (tail_bytes) {
38		memcpy(block_buffer, src, tail_bytes);
39		chacha_zvkb(state, block_buffer, block_buffer, 1, nrounds);
40		memcpy(dst, block_buffer, tail_bytes);
41	}
42	kernel_vector_end();
43}
44
45#define chacha_mod_init_arch chacha_mod_init_arch
46static void chacha_mod_init_arch(void)
47{
48	if (riscv_isa_extension_available(NULL, ZVKB) &&
49	    riscv_vector_vlen() >= 128)
50		static_branch_enable(&use_zvkb);
51}