102 lines
2.8 KiB
C
102 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* ChaCha20 using the RISC-V vector crypto extensions
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*
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* Copyright (C) 2023 SiFive, Inc.
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* Author: Jerry Shih <jerry.shih@sifive.com>
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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/internal/chacha.h>
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#include <crypto/internal/skcipher.h>
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#include <linux/linkage.h>
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#include <linux/module.h>
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asmlinkage void chacha20_zvkb(const u32 key[8], const u8 *in, u8 *out,
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size_t len, const u32 iv[4]);
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static int riscv64_chacha20_crypt(struct skcipher_request *req)
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{
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u32 iv[CHACHA_IV_SIZE / sizeof(u32)];
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u8 block_buffer[CHACHA_BLOCK_SIZE];
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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const struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
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struct skcipher_walk walk;
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unsigned int nbytes;
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unsigned int tail_bytes;
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int err;
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iv[0] = get_unaligned_le32(req->iv);
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iv[1] = get_unaligned_le32(req->iv + 4);
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iv[2] = get_unaligned_le32(req->iv + 8);
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iv[3] = get_unaligned_le32(req->iv + 12);
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err = skcipher_walk_virt(&walk, req, false);
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while (walk.nbytes) {
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nbytes = walk.nbytes & ~(CHACHA_BLOCK_SIZE - 1);
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tail_bytes = walk.nbytes & (CHACHA_BLOCK_SIZE - 1);
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kernel_vector_begin();
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if (nbytes) {
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chacha20_zvkb(ctx->key, walk.src.virt.addr,
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walk.dst.virt.addr, nbytes, iv);
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iv[0] += nbytes / CHACHA_BLOCK_SIZE;
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}
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if (walk.nbytes == walk.total && tail_bytes > 0) {
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memcpy(block_buffer, walk.src.virt.addr + nbytes,
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tail_bytes);
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chacha20_zvkb(ctx->key, block_buffer, block_buffer,
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CHACHA_BLOCK_SIZE, iv);
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memcpy(walk.dst.virt.addr + nbytes, block_buffer,
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tail_bytes);
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tail_bytes = 0;
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}
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kernel_vector_end();
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err = skcipher_walk_done(&walk, tail_bytes);
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}
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return err;
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}
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static struct skcipher_alg riscv64_chacha_alg = {
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.setkey = chacha20_setkey,
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.encrypt = riscv64_chacha20_crypt,
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.decrypt = riscv64_chacha20_crypt,
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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = CHACHA_IV_SIZE,
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.chunksize = CHACHA_BLOCK_SIZE,
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.walksize = 4 * CHACHA_BLOCK_SIZE,
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.base = {
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.cra_blocksize = 1,
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.cra_ctxsize = sizeof(struct chacha_ctx),
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.cra_priority = 300,
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.cra_name = "chacha20",
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.cra_driver_name = "chacha20-riscv64-zvkb",
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.cra_module = THIS_MODULE,
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},
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};
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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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return crypto_register_skcipher(&riscv64_chacha_alg);
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return -ENODEV;
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}
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static void __exit riscv64_chacha_mod_exit(void)
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{
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crypto_unregister_skcipher(&riscv64_chacha_alg);
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}
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module_init(riscv64_chacha_mod_init);
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module_exit(riscv64_chacha_mod_exit);
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MODULE_DESCRIPTION("ChaCha20 (RISC-V accelerated)");
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MODULE_AUTHOR("Jerry Shih <jerry.shih@sifive.com>");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_CRYPTO("chacha20");
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