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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/lib/crypto/riscv/chacha-riscv64-glue.c
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// SPDX-License-Identifier: GPL-2.0-only

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/*

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 * ChaCha stream cipher (RISC-V optimized)

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 *

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 * Copyright (C) 2023 SiFive, Inc.

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 * Author: Jerry Shih <[email protected]>

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 */

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#include <asm/simd.h>

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#include <asm/vector.h>

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#include <crypto/chacha.h>

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#include <crypto/internal/simd.h>

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#include <linux/linkage.h>

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#include <linux/module.h>

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static __ro_after_init DEFINE_STATIC_KEY_FALSE(use_zvkb);

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asmlinkage void chacha_zvkb(struct chacha_state *state, const u8 *in, u8 *out,

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			    size_t nblocks, int nrounds);

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void hchacha_block_arch(const struct chacha_state *state,

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			u32 out[HCHACHA_OUT_WORDS], int nrounds)

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{

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	hchacha_block_generic(state, out, nrounds);

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}

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EXPORT_SYMBOL(hchacha_block_arch);

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void chacha_crypt_arch(struct chacha_state *state, u8 *dst, const u8 *src,

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		       unsigned int bytes, int nrounds)

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{

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	u8 block_buffer[CHACHA_BLOCK_SIZE];

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	unsigned int full_blocks = bytes / CHACHA_BLOCK_SIZE;

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	unsigned int tail_bytes = bytes % CHACHA_BLOCK_SIZE;

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

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

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	kernel_vector_begin();

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	if (full_blocks) {

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

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		src += full_blocks * CHACHA_BLOCK_SIZE;

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		dst += full_blocks * CHACHA_BLOCK_SIZE;

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	}

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	if (tail_bytes) {

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		memcpy(block_buffer, src, tail_bytes);

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

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		memcpy(dst, block_buffer, tail_bytes);

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	}

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	kernel_vector_end();

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}

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EXPORT_SYMBOL(chacha_crypt_arch);

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bool chacha_is_arch_optimized(void)

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{

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	return static_key_enabled(&use_zvkb);

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}

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EXPORT_SYMBOL(chacha_is_arch_optimized);

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static int __init riscv64_chacha_mod_init(void)

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{

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	if (riscv_isa_extension_available(NULL, ZVKB) &&

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	    riscv_vector_vlen() >= 128)

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		static_branch_enable(&use_zvkb);

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	return 0;

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}

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subsys_initcall(riscv64_chacha_mod_init);

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static void __exit riscv64_chacha_mod_exit(void)

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{

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}

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module_exit(riscv64_chacha_mod_exit);

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

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MODULE_AUTHOR("Jerry Shih <[email protected]>");

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MODULE_LICENSE("GPL");

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