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/internal/simd.h>
22 #include <linux/jump_label.h>
23 #include <linux/kernel.h>
24
25 #include <asm/hwcap.h>
26 #include <asm/neon.h>
27 #include <asm/simd.h>
28
29 asmlinkage void chacha_block_xor_neon(const struct chacha_state *state,
30 u8 *dst, const u8 *src, int nrounds);
31 asmlinkage void chacha_4block_xor_neon(const struct chacha_state *state,
32 u8 *dst, const u8 *src,
33 int nrounds, int bytes);
34 asmlinkage void hchacha_block_neon(const struct chacha_state *state,
35 u32 out[HCHACHA_OUT_WORDS], int nrounds);
36
37 static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
38
chacha_doneon(struct chacha_state * state,u8 * dst,const u8 * src,int bytes,int nrounds)39 static void chacha_doneon(struct chacha_state *state, u8 *dst, const u8 *src,
40 int bytes, int nrounds)
41 {
42 while (bytes > 0) {
43 int l = min(bytes, CHACHA_BLOCK_SIZE * 5);
44
45 if (l <= CHACHA_BLOCK_SIZE) {
46 u8 buf[CHACHA_BLOCK_SIZE];
47
48 memcpy(buf, src, l);
49 chacha_block_xor_neon(state, buf, buf, nrounds);
50 memcpy(dst, buf, l);
51 state->x[12] += 1;
52 break;
53 }
54 chacha_4block_xor_neon(state, dst, src, nrounds, l);
55 bytes -= l;
56 src += l;
57 dst += l;
58 state->x[12] += DIV_ROUND_UP(l, CHACHA_BLOCK_SIZE);
59 }
60 }
61
hchacha_block_arch(const struct chacha_state * state,u32 out[HCHACHA_OUT_WORDS],int nrounds)62 static void hchacha_block_arch(const struct chacha_state *state,
63 u32 out[HCHACHA_OUT_WORDS], int nrounds)
64 {
65 if (!static_branch_likely(&have_neon) || !crypto_simd_usable()) {
66 hchacha_block_generic(state, out, nrounds);
67 } else {
68 kernel_neon_begin();
69 hchacha_block_neon(state, out, nrounds);
70 kernel_neon_end();
71 }
72 }
73
chacha_crypt_arch(struct chacha_state * state,u8 * dst,const u8 * src,unsigned int bytes,int nrounds)74 static void chacha_crypt_arch(struct chacha_state *state, u8 *dst,
75 const u8 *src, unsigned int bytes, int nrounds)
76 {
77 if (!static_branch_likely(&have_neon) || bytes <= CHACHA_BLOCK_SIZE ||
78 !crypto_simd_usable())
79 return chacha_crypt_generic(state, dst, src, bytes, nrounds);
80
81 do {
82 unsigned int todo = min_t(unsigned int, bytes, SZ_4K);
83
84 kernel_neon_begin();
85 chacha_doneon(state, dst, src, todo, nrounds);
86 kernel_neon_end();
87
88 bytes -= todo;
89 src += todo;
90 dst += todo;
91 } while (bytes);
92 }
93
94 #define chacha_mod_init_arch chacha_mod_init_arch
chacha_mod_init_arch(void)95 static void chacha_mod_init_arch(void)
96 {
97 if (cpu_have_named_feature(ASIMD))
98 static_branch_enable(&have_neon);
99 }
100