tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * ChaCha and HChaCha functions (ARM64 optimized)
3 *
4 * Copyright (C) 2016 - 2017 Linaro, Ltd. <ard.biesheuvel@linaro.org>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Based on:
11 * ChaCha20 256-bit cipher algorithm, RFC7539, SIMD glue code
12 *
13 * Copyright (C) 2015 Martin Willi
14 *
15 * This program is free software; you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License as published by
17 * the Free Software Foundation; either version 2 of the License, or
18 * (at your option) any later version.
19 */
20
21#include <crypto/chacha.h>
22#include <crypto/internal/simd.h>
23#include <linux/jump_label.h>
24#include <linux/kernel.h>
25#include <linux/module.h>
26
27#include <asm/hwcap.h>
28#include <asm/neon.h>
29#include <asm/simd.h>
30
31asmlinkage void chacha_block_xor_neon(const struct chacha_state *state,
32 u8 *dst, const u8 *src, int nrounds);
33asmlinkage void chacha_4block_xor_neon(const struct chacha_state *state,
34 u8 *dst, const u8 *src,
35 int nrounds, int bytes);
36asmlinkage void hchacha_block_neon(const struct chacha_state *state,
37 u32 out[HCHACHA_OUT_WORDS], int nrounds);
38
39static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
40
41static void chacha_doneon(struct chacha_state *state, u8 *dst, const u8 *src,
42 int bytes, int nrounds)
43{
44 while (bytes > 0) {
45 int l = min(bytes, CHACHA_BLOCK_SIZE * 5);
46
47 if (l <= CHACHA_BLOCK_SIZE) {
48 u8 buf[CHACHA_BLOCK_SIZE];
49
50 memcpy(buf, src, l);
51 chacha_block_xor_neon(state, buf, buf, nrounds);
52 memcpy(dst, buf, l);
53 state->x[12] += 1;
54 break;
55 }
56 chacha_4block_xor_neon(state, dst, src, nrounds, l);
57 bytes -= l;
58 src += l;
59 dst += l;
60 state->x[12] += DIV_ROUND_UP(l, CHACHA_BLOCK_SIZE);
61 }
62}
63
64void hchacha_block_arch(const struct chacha_state *state,
65 u32 out[HCHACHA_OUT_WORDS], int nrounds)
66{
67 if (!static_branch_likely(&have_neon) || !crypto_simd_usable()) {
68 hchacha_block_generic(state, out, nrounds);
69 } else {
70 kernel_neon_begin();
71 hchacha_block_neon(state, out, nrounds);
72 kernel_neon_end();
73 }
74}
75EXPORT_SYMBOL(hchacha_block_arch);
76
77void chacha_crypt_arch(struct chacha_state *state, u8 *dst, const u8 *src,
78 unsigned int bytes, int nrounds)
79{
80 if (!static_branch_likely(&have_neon) || bytes <= CHACHA_BLOCK_SIZE ||
81 !crypto_simd_usable())
82 return chacha_crypt_generic(state, dst, src, bytes, nrounds);
83
84 do {
85 unsigned int todo = min_t(unsigned int, bytes, SZ_4K);
86
87 kernel_neon_begin();
88 chacha_doneon(state, dst, src, todo, nrounds);
89 kernel_neon_end();
90
91 bytes -= todo;
92 src += todo;
93 dst += todo;
94 } while (bytes);
95}
96EXPORT_SYMBOL(chacha_crypt_arch);
97
98bool chacha_is_arch_optimized(void)
99{
100 return static_key_enabled(&have_neon);
101}
102EXPORT_SYMBOL(chacha_is_arch_optimized);
103
104static int __init chacha_simd_mod_init(void)
105{
106 if (cpu_have_named_feature(ASIMD))
107 static_branch_enable(&have_neon);
108 return 0;
109}
110subsys_initcall(chacha_simd_mod_init);
111
112static void __exit chacha_simd_mod_exit(void)
113{
114}
115module_exit(chacha_simd_mod_exit);
116
117MODULE_DESCRIPTION("ChaCha and HChaCha functions (ARM64 optimized)");
118MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
119MODULE_LICENSE("GPL v2");