1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2024 Xi Ruoyao <xry111@xry111.
4 */
5
6 #include <asm/asm.h>
7 #include <asm/regdef.h>
8 #include <linux/linkage.h>
9
10 .text
11
12 .macro OP_4REG op d0 d1 d2 d3 s0 s1 s2 s3
13 \op \d0, \d0, \s0
14 \op \d1, \d1, \s1
15 \op \d2, \d2, \s2
16 \op \d3, \d3, \s3
17 .endm
18
19 /*
20 * Very basic LoongArch implementation of ChaC
21 * number of blocks of output with a nonce of
22 * 8-byte counter. Importantly does not spill
23 * are:
24 *
25 * a0: output bytes
26 * a1: 32-byte key input
27 * a2: 8-byte counter input/output
28 * a3: number of 64-byte blocks to write
29 */
30 SYM_FUNC_START(__arch_chacha20_blocks_nostack)
31
32 /* We don't need a frame pointer */
33 #define s9 fp
34
35 #define output a0
36 #define key a1
37 #define counter a2
38 #define nblocks a3
39 #define i a4
40 #define state0 s0
41 #define state1 s1
42 #define state2 s2
43 #define state3 s3
44 #define state4 s4
45 #define state5 s5
46 #define state6 s6
47 #define state7 s7
48 #define state8 s8
49 #define state9 s9
50 #define state10 a5
51 #define state11 a6
52 #define state12 a7
53 #define state13 t0
54 #define state14 t1
55 #define state15 t2
56 #define cnt_lo t3
57 #define cnt_hi t4
58 #define copy0 t5
59 #define copy1 t6
60 #define copy2 t7
61
62 /* Reuse i as copy3 */
63 #define copy3 i
64
65 /* Packs to be used with OP_4REG */
66 #define line0 state0, state1, state2
67 #define line1 state4, state5, state6
68 #define line2 state8, state9, state1
69 #define line3 state12, state13, stat
70
71 #define line1_perm state5, state6, state7
72 #define line2_perm state10, state11, stat
73 #define line3_perm state15, state12, stat
74
75 #define copy copy0, copy1, copy2, c
76
77 #define _16 16, 16, 16, 16
78 #define _20 20, 20, 20, 20
79 #define _24 24, 24, 24, 24
80 #define _25 25, 25, 25, 25
81
82 /*
83 * The ABI requires s0-s9 saved, and s
84 * This does not violate the stack-les
85 * is spilled onto the stack.
86 */
87 PTR_ADDI sp, sp, (-SZREG * 10)
88 REG_S s0, sp, 0
89 REG_S s1, sp, SZREG
90 REG_S s2, sp, SZREG * 2
91 REG_S s3, sp, SZREG * 3
92 REG_S s4, sp, SZREG * 4
93 REG_S s5, sp, SZREG * 5
94 REG_S s6, sp, SZREG * 6
95 REG_S s7, sp, SZREG * 7
96 REG_S s8, sp, SZREG * 8
97 REG_S s9, sp, SZREG * 9
98
99 li.w copy0, 0x61707865
100 li.w copy1, 0x3320646e
101 li.w copy2, 0x79622d32
102
103 ld.w cnt_lo, counter, 0
104 ld.w cnt_hi, counter, 4
105
106 .Lblock:
107 /* state[0,1,2,3] = "expand 32-byte k"
108 move state0, copy0
109 move state1, copy1
110 move state2, copy2
111 li.w state3, 0x6b206574
112
113 /* state[4,5,..,11] = key */
114 ld.w state4, key, 0
115 ld.w state5, key, 4
116 ld.w state6, key, 8
117 ld.w state7, key, 12
118 ld.w state8, key, 16
119 ld.w state9, key, 20
120 ld.w state10, key, 24
121 ld.w state11, key, 28
122
123 /* state[12,13] = counter */
124 move state12, cnt_lo
125 move state13, cnt_hi
126
127 /* state[14,15] = 0 */
128 move state14, zero
129 move state15, zero
130
131 li.w i, 10
132 .Lpermute:
133 /* odd round */
134 OP_4REG add.w line0, line1
135 OP_4REG xor line3, line0
136 OP_4REG rotri.w line3, _16
137
138 OP_4REG add.w line2, line3
139 OP_4REG xor line1, line2
140 OP_4REG rotri.w line1, _20
141
142 OP_4REG add.w line0, line1
143 OP_4REG xor line3, line0
144 OP_4REG rotri.w line3, _24
145
146 OP_4REG add.w line2, line3
147 OP_4REG xor line1, line2
148 OP_4REG rotri.w line1, _25
149
150 /* even round */
151 OP_4REG add.w line0, line1_perm
152 OP_4REG xor line3_perm, line0
153 OP_4REG rotri.w line3_perm, _16
154
155 OP_4REG add.w line2_perm, line3_perm
156 OP_4REG xor line1_perm, line2_perm
157 OP_4REG rotri.w line1_perm, _20
158
159 OP_4REG add.w line0, line1_perm
160 OP_4REG xor line3_perm, line0
161 OP_4REG rotri.w line3_perm, _24
162
163 OP_4REG add.w line2_perm, line3_perm
164 OP_4REG xor line1_perm, line2_perm
165 OP_4REG rotri.w line1_perm, _25
166
167 addi.w i, i, -1
168 bnez i, .Lpermute
169
170 /*
171 * copy[3] = "expa", materialize it he
172 * same register with i which just bec
173 */
174 li.w copy3, 0x6b206574
175
176 /* output[0,1,2,3] = copy[0,1,2,3] + s
177 OP_4REG add.w line0, copy
178 st.w state0, output, 0
179 st.w state1, output, 4
180 st.w state2, output, 8
181 st.w state3, output, 12
182
183 /* from now on state[0,1,2,3] are scra
184
185 /* state[0,1,2,3] = lo32(key) */
186 ld.w state0, key, 0
187 ld.w state1, key, 4
188 ld.w state2, key, 8
189 ld.w state3, key, 12
190
191 /* output[4,5,6,7] = state[0,1,2,3] +
192 OP_4REG add.w line1, line0
193 st.w state4, output, 16
194 st.w state5, output, 20
195 st.w state6, output, 24
196 st.w state7, output, 28
197
198 /* state[0,1,2,3] = hi32(key) */
199 ld.w state0, key, 16
200 ld.w state1, key, 20
201 ld.w state2, key, 24
202 ld.w state3, key, 28
203
204 /* output[8,9,10,11] = state[0,1,2,3]
205 OP_4REG add.w line2, line0
206 st.w state8, output, 32
207 st.w state9, output, 36
208 st.w state10, output, 40
209 st.w state11, output, 44
210
211 /* output[12,13,14,15] = state[12,13,1
212 add.w state12, state12, cnt_
213 add.w state13, state13, cnt_
214 st.w state12, output, 48
215 st.w state13, output, 52
216 st.w state14, output, 56
217 st.w state15, output, 60
218
219 /* ++counter */
220 addi.w cnt_lo, cnt_lo, 1
221 sltui state0, cnt_lo, 1
222 add.w cnt_hi, cnt_hi, state0
223
224 /* output += 64 */
225 PTR_ADDI output, output, 64
226 /* --nblocks */
227 PTR_ADDI nblocks, nblocks, -1
228 bnez nblocks, .Lblock
229
230 /* counter = [cnt_lo, cnt_hi] */
231 st.w cnt_lo, counter, 0
232 st.w cnt_hi, counter, 4
233
234 /*
235 * Zero out the potentially sensitive
236 * again. As at now copy[0,1,2,3] just
237 * state[0,...,9] are s0-s9 those we'l
238 * only need to zero state[11,...,15].
239 */
240 move state10, zero
241 move state11, zero
242 move state12, zero
243 move state13, zero
244 move state14, zero
245 move state15, zero
246
247 REG_L s0, sp, 0
248 REG_L s1, sp, SZREG
249 REG_L s2, sp, SZREG * 2
250 REG_L s3, sp, SZREG * 3
251 REG_L s4, sp, SZREG * 4
252 REG_L s5, sp, SZREG * 5
253 REG_L s6, sp, SZREG * 6
254 REG_L s7, sp, SZREG * 7
255 REG_L s8, sp, SZREG * 8
256 REG_L s9, sp, SZREG * 9
257 PTR_ADDI sp, sp, -((-SZREG * 10
258
259 jr ra
260 SYM_FUNC_END(__arch_chacha20_blocks_nostack)
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