Some documentation fixes.
[BearSSL] / src / symcipher / chacha20_sse2.c
1 /*
2 * Copyright (c) 2017 Thomas Pornin <pornin@bolet.org>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 * SOFTWARE.
23 */
24
25 #define BR_ENABLE_INTRINSICS 1
26 #include "inner.h"
27
28 #if BR_SSE2
29
30 /*
31 * This file contains a ChaCha20 implementation that leverages SSE2
32 * opcodes for better performance.
33 */
34
35 /* see bearssl_block.h */
36 br_chacha20_run
37 br_chacha20_sse2_get(void)
38 {
39 /*
40 * If using 64-bit mode, then SSE2 opcodes should be automatically
41 * available, since they are part of the ABI.
42 *
43 * In 32-bit mode, we use CPUID to detect the SSE2 feature.
44 */
45
46 #if BR_amd64
47 return &br_chacha20_sse2_run;
48 #else
49
50 /*
51 * SSE2 support is indicated by bit 26 in EDX.
52 */
53 if (br_cpuid(0, 0, 0, 0x04000000)) {
54 return &br_chacha20_sse2_run;
55 } else {
56 return 0;
57 }
58 #endif
59 }
60
61 BR_TARGETS_X86_UP
62
63 /* see bearssl_block.h */
64 BR_TARGET("sse2")
65 uint32_t
66 br_chacha20_sse2_run(const void *key,
67 const void *iv, uint32_t cc, void *data, size_t len)
68 {
69 unsigned char *buf;
70 uint32_t ivtmp[4];
71 __m128i kw0, kw1;
72 __m128i iw, cw;
73 __m128i one;
74
75 static const uint32_t CW[] = {
76 0x61707865, 0x3320646e, 0x79622d32, 0x6b206574
77 };
78
79 buf = data;
80 kw0 = _mm_loadu_si128(key);
81 kw1 = _mm_loadu_si128((const void *)((const unsigned char *)key + 16));
82 ivtmp[0] = cc;
83 memcpy(ivtmp + 1, iv, 12);
84 iw = _mm_loadu_si128((const void *)ivtmp);
85 cw = _mm_loadu_si128((const void *)CW);
86 one = _mm_set_epi32(0, 0, 0, 1);
87
88 while (len > 0) {
89 /*
90 * sj contains state words 4*j to 4*j+3.
91 */
92 __m128i s0, s1, s2, s3;
93 int i;
94
95 s0 = cw;
96 s1 = kw0;
97 s2 = kw1;
98 s3 = iw;
99 for (i = 0; i < 10; i ++) {
100 /*
101 * Even round is straightforward application on
102 * the state words.
103 */
104 s0 = _mm_add_epi32(s0, s1);
105 s3 = _mm_xor_si128(s3, s0);
106 s3 = _mm_or_si128(
107 _mm_slli_epi32(s3, 16),
108 _mm_srli_epi32(s3, 16));
109
110 s2 = _mm_add_epi32(s2, s3);
111 s1 = _mm_xor_si128(s1, s2);
112 s1 = _mm_or_si128(
113 _mm_slli_epi32(s1, 12),
114 _mm_srli_epi32(s1, 20));
115
116 s0 = _mm_add_epi32(s0, s1);
117 s3 = _mm_xor_si128(s3, s0);
118 s3 = _mm_or_si128(
119 _mm_slli_epi32(s3, 8),
120 _mm_srli_epi32(s3, 24));
121
122 s2 = _mm_add_epi32(s2, s3);
123 s1 = _mm_xor_si128(s1, s2);
124 s1 = _mm_or_si128(
125 _mm_slli_epi32(s1, 7),
126 _mm_srli_epi32(s1, 25));
127
128 /*
129 * For the odd round, we must rotate some state
130 * words so that the computations apply on the
131 * right combinations of words.
132 */
133 s1 = _mm_shuffle_epi32(s1, 0x39);
134 s2 = _mm_shuffle_epi32(s2, 0x4E);
135 s3 = _mm_shuffle_epi32(s3, 0x93);
136
137 s0 = _mm_add_epi32(s0, s1);
138 s3 = _mm_xor_si128(s3, s0);
139 s3 = _mm_or_si128(
140 _mm_slli_epi32(s3, 16),
141 _mm_srli_epi32(s3, 16));
142
143 s2 = _mm_add_epi32(s2, s3);
144 s1 = _mm_xor_si128(s1, s2);
145 s1 = _mm_or_si128(
146 _mm_slli_epi32(s1, 12),
147 _mm_srli_epi32(s1, 20));
148
149 s0 = _mm_add_epi32(s0, s1);
150 s3 = _mm_xor_si128(s3, s0);
151 s3 = _mm_or_si128(
152 _mm_slli_epi32(s3, 8),
153 _mm_srli_epi32(s3, 24));
154
155 s2 = _mm_add_epi32(s2, s3);
156 s1 = _mm_xor_si128(s1, s2);
157 s1 = _mm_or_si128(
158 _mm_slli_epi32(s1, 7),
159 _mm_srli_epi32(s1, 25));
160
161 /*
162 * After the odd round, we rotate back the values
163 * to undo the rotate at the start of the odd round.
164 */
165 s1 = _mm_shuffle_epi32(s1, 0x93);
166 s2 = _mm_shuffle_epi32(s2, 0x4E);
167 s3 = _mm_shuffle_epi32(s3, 0x39);
168 }
169
170 /*
171 * Addition with the initial state.
172 */
173 s0 = _mm_add_epi32(s0, cw);
174 s1 = _mm_add_epi32(s1, kw0);
175 s2 = _mm_add_epi32(s2, kw1);
176 s3 = _mm_add_epi32(s3, iw);
177
178 /*
179 * Increment block counter.
180 */
181 iw = _mm_add_epi32(iw, one);
182
183 /*
184 * XOR final state with the data.
185 */
186 if (len < 64) {
187 unsigned char tmp[64];
188 size_t u;
189
190 _mm_storeu_si128((void *)(tmp + 0), s0);
191 _mm_storeu_si128((void *)(tmp + 16), s1);
192 _mm_storeu_si128((void *)(tmp + 32), s2);
193 _mm_storeu_si128((void *)(tmp + 48), s3);
194 for (u = 0; u < len; u ++) {
195 buf[u] ^= tmp[u];
196 }
197 break;
198 } else {
199 __m128i b0, b1, b2, b3;
200
201 b0 = _mm_loadu_si128((const void *)(buf + 0));
202 b1 = _mm_loadu_si128((const void *)(buf + 16));
203 b2 = _mm_loadu_si128((const void *)(buf + 32));
204 b3 = _mm_loadu_si128((const void *)(buf + 48));
205 b0 = _mm_xor_si128(b0, s0);
206 b1 = _mm_xor_si128(b1, s1);
207 b2 = _mm_xor_si128(b2, s2);
208 b3 = _mm_xor_si128(b3, s3);
209 _mm_storeu_si128((void *)(buf + 0), b0);
210 _mm_storeu_si128((void *)(buf + 16), b1);
211 _mm_storeu_si128((void *)(buf + 32), b2);
212 _mm_storeu_si128((void *)(buf + 48), b3);
213 buf += 64;
214 len -= 64;
215 }
216 }
217
218 /*
219 * _mm_extract_epi32() requires SSE4.1. We prefer to stick to
220 * raw SSE2, thus we use _mm_extract_epi16().
221 */
222 return (uint32_t)_mm_extract_epi16(iw, 0)
223 | ((uint32_t)_mm_extract_epi16(iw, 1) << 16);
224 }
225
226 BR_TARGETS_X86_DOWN
227
228 #else
229
230 /* see bearssl_block.h */
231 br_chacha20_run
232 br_chacha20_sse2_get(void)
233 {
234 return 0;
235 }
236
237 #endif