1 //
2 // Accelerated CRC-T10DIF using ARM NEON and Crypto Extensions instructions
3 //
4 // Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org>
5 // Copyright (C) 2019 Google LLC <ebiggers@google.com>
6 //
7 // This program is free software; you can redistribute it and/or modify
8 // it under the terms of the GNU General Public License version 2 as
9 // published by the Free Software Foundation.
10 //
11
12 // Derived from the x86 version:
13 //
14 // Implement fast CRC-T10DIF computation with SSE and PCLMULQDQ instructions
15 //
16 // Copyright (c) 2013, Intel Corporation
17 //
18 // Authors:
19 // Erdinc Ozturk <erdinc.ozturk@intel.com>
20 // Vinodh Gopal <vinodh.gopal@intel.com>
21 // James Guilford <james.guilford@intel.com>
22 // Tim Chen <tim.c.chen@linux.intel.com>
23 //
24 // This software is available to you under a choice of one of two
25 // licenses. You may choose to be licensed under the terms of the GNU
26 // General Public License (GPL) Version 2, available from the file
27 // COPYING in the main directory of this source tree, or the
28 // OpenIB.org BSD license below:
29 //
30 // Redistribution and use in source and binary forms, with or without
31 // modification, are permitted provided that the following conditions are
32 // met:
33 //
34 // * Redistributions of source code must retain the above copyright
35 // notice, this list of conditions and the following disclaimer.
36 //
37 // * Redistributions in binary form must reproduce the above copyright
38 // notice, this list of conditions and the following disclaimer in the
39 // documentation and/or other materials provided with the
40 // distribution.
41 //
42 // * Neither the name of the Intel Corporation nor the names of its
43 // contributors may be used to endorse or promote products derived from
44 // this software without specific prior written permission.
45 //
46 //
47 // THIS SOFTWARE IS PROVIDED BY INTEL CORPORATION ""AS IS"" AND ANY
48 // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
49 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
50 // PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL CORPORATION OR
51 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
52 // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
53 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
54 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
55 // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
56 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
57 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
58 //
59 // Reference paper titled "Fast CRC Computation for Generic
60 // Polynomials Using PCLMULQDQ Instruction"
61 // URL: http://www.intel.com/content/dam/www/public/us/en/documents
62 // /white-papers/fast-crc-computation-generic-polynomials-pclmulqdq-paper.pdf
63 //
64
65 #include <linux/linkage.h>
66 #include <asm/assembler.h>
67
68 #ifdef CONFIG_CPU_ENDIAN_BE8
69 #define CPU_LE(code...)
70 #else
71 #define CPU_LE(code...) code
72 #endif
73
74 .text
75 .arch armv7-a
76 .fpu crypto-neon-fp-armv8
77
78 init_crc .req r0
79 buf .req r1
80 len .req r2
81
82 fold_consts_ptr .req ip
83
84 q0l .req d0
85 q0h .req d1
86 q1l .req d2
87 q1h .req d3
88 q2l .req d4
89 q2h .req d5
90 q3l .req d6
91 q3h .req d7
92 q4l .req d8
93 q4h .req d9
94 q5l .req d10
95 q5h .req d11
96 q6l .req d12
97 q6h .req d13
98 q7l .req d14
99 q7h .req d15
100 q8l .req d16
101 q8h .req d17
102 q9l .req d18
103 q9h .req d19
104 q10l .req d20
105 q10h .req d21
106 q11l .req d22
107 q11h .req d23
108 q12l .req d24
109 q12h .req d25
110
111 FOLD_CONSTS .req q10
112 FOLD_CONST_L .req q10l
113 FOLD_CONST_H .req q10h
114
115 // Fold reg1, reg2 into the next 32 data bytes, storing the result back
116 // into reg1, reg2.
117 .macro fold_32_bytes, reg1, reg2
118 vld1.64 {q11-q12}, [buf]!
119
120 vmull.p64 q8, \reg1\()h, FOLD_CONST_H
121 vmull.p64 \reg1, \reg1\()l, FOLD_CONST_L
122 vmull.p64 q9, \reg2\()h, FOLD_CONST_H
123 vmull.p64 \reg2, \reg2\()l, FOLD_CONST_L
124
125 CPU_LE( vrev64.8 q11, q11 )
126 CPU_LE( vrev64.8 q12, q12 )
127 vswp q11l, q11h
128 vswp q12l, q12h
129
130 veor.8 \reg1, \reg1, q8
131 veor.8 \reg2, \reg2, q9
132 veor.8 \reg1, \reg1, q11
133 veor.8 \reg2, \reg2, q12
134 .endm
135
136 // Fold src_reg into dst_reg, optionally loading the next fold constants
137 .macro fold_16_bytes, src_reg, dst_reg, load_next_consts
138 vmull.p64 q8, \src_reg\()l, FOLD_CONST_L
139 vmull.p64 \src_reg, \src_reg\()h, FOLD_CONST_H
140 .ifnb \load_next_consts
141 vld1.64 {FOLD_CONSTS}, [fold_consts_ptr, :128]!
142 .endif
143 veor.8 \dst_reg, \dst_reg, q8
144 veor.8 \dst_reg, \dst_reg, \src_reg
145 .endm
146
147 .macro __adrl, out, sym
148 movw \out, #:lower16:\sym
149 movt \out, #:upper16:\sym
150 .endm
151
152 //
153 // u16 crc_t10dif_pmull(u16 init_crc, const u8 *buf, size_t len);
154 //
155 // Assumes len >= 16.
156 //
157 ENTRY(crc_t10dif_pmull)
158
159 // For sizes less than 256 bytes, we can't fold 128 bytes at a time.
160 cmp len, #256
161 blt .Lless_than_256_bytes
162
163 __adrl fold_consts_ptr, .Lfold_across_128_bytes_consts
164
165 // Load the first 128 data bytes. Byte swapping is necessary to make
166 // the bit order match the polynomial coefficient order.
167 vld1.64 {q0-q1}, [buf]!
168 vld1.64 {q2-q3}, [buf]!
169 vld1.64 {q4-q5}, [buf]!
170 vld1.64 {q6-q7}, [buf]!
171 CPU_LE( vrev64.8 q0, q0 )
172 CPU_LE( vrev64.8 q1, q1 )
173 CPU_LE( vrev64.8 q2, q2 )
174 CPU_LE( vrev64.8 q3, q3 )
175 CPU_LE( vrev64.8 q4, q4 )
176 CPU_LE( vrev64.8 q5, q5 )
177 CPU_LE( vrev64.8 q6, q6 )
178 CPU_LE( vrev64.8 q7, q7 )
179 vswp q0l, q0h
180 vswp q1l, q1h
181 vswp q2l, q2h
182 vswp q3l, q3h
183 vswp q4l, q4h
184 vswp q5l, q5h
185 vswp q6l, q6h
186 vswp q7l, q7h
187
188 // XOR the first 16 data *bits* with the initial CRC value.
189 vmov.i8 q8h, #0
190 vmov.u16 q8h[3], init_crc
191 veor q0h, q0h, q8h
192
193 // Load the constants for folding across 128 bytes.
194 vld1.64 {FOLD_CONSTS}, [fold_consts_ptr, :128]!
195
196 // Subtract 128 for the 128 data bytes just consumed. Subtract another
197 // 128 to simplify the termination condition of the following loop.
198 sub len, len, #256
199
200 // While >= 128 data bytes remain (not counting q0-q7), fold the 128
201 // bytes q0-q7 into them, storing the result back into q0-q7.
202 .Lfold_128_bytes_loop:
203 fold_32_bytes q0, q1
204 fold_32_bytes q2, q3
205 fold_32_bytes q4, q5
206 fold_32_bytes q6, q7
207 subs len, len, #128
208 bge .Lfold_128_bytes_loop
209
210 // Now fold the 112 bytes in q0-q6 into the 16 bytes in q7.
211
212 // Fold across 64 bytes.
213 vld1.64 {FOLD_CONSTS}, [fold_consts_ptr, :128]!
214 fold_16_bytes q0, q4
215 fold_16_bytes q1, q5
216 fold_16_bytes q2, q6
217 fold_16_bytes q3, q7, 1
218 // Fold across 32 bytes.
219 fold_16_bytes q4, q6
220 fold_16_bytes q5, q7, 1
221 // Fold across 16 bytes.
222 fold_16_bytes q6, q7
223
224 // Add 128 to get the correct number of data bytes remaining in 0...127
225 // (not counting q7), following the previous extra subtraction by 128.
226 // Then subtract 16 to simplify the termination condition of the
227 // following loop.
228 adds len, len, #(128-16)
229
230 // While >= 16 data bytes remain (not counting q7), fold the 16 bytes q7
231 // into them, storing the result back into q7.
232 blt .Lfold_16_bytes_loop_done
233 .Lfold_16_bytes_loop:
234 vmull.p64 q8, q7l, FOLD_CONST_L
235 vmull.p64 q7, q7h, FOLD_CONST_H
236 veor.8 q7, q7, q8
237 vld1.64 {q0}, [buf]!
238 CPU_LE( vrev64.8 q0, q0 )
239 vswp q0l, q0h
240 veor.8 q7, q7, q0
241 subs len, len, #16
242 bge .Lfold_16_bytes_loop
243
244 .Lfold_16_bytes_loop_done:
245 // Add 16 to get the correct number of data bytes remaining in 0...15
246 // (not counting q7), following the previous extra subtraction by 16.
247 adds len, len, #16
248 beq .Lreduce_final_16_bytes
249
250 .Lhandle_partial_segment:
251 // Reduce the last '16 + len' bytes where 1 <= len <= 15 and the first
252 // 16 bytes are in q7 and the rest are the remaining data in 'buf'. To
253 // do this without needing a fold constant for each possible 'len',
254 // redivide the bytes into a first chunk of 'len' bytes and a second
255 // chunk of 16 bytes, then fold the first chunk into the second.
256
257 // q0 = last 16 original data bytes
258 add buf, buf, len
259 sub buf, buf, #16
260 vld1.64 {q0}, [buf]
261 CPU_LE( vrev64.8 q0, q0 )
262 vswp q0l, q0h
263
264 // q1 = high order part of second chunk: q7 left-shifted by 'len' bytes.
265 __adrl r3, .Lbyteshift_table + 16
266 sub r3, r3, len
267 vld1.8 {q2}, [r3]
268 vtbl.8 q1l, {q7l-q7h}, q2l
269 vtbl.8 q1h, {q7l-q7h}, q2h
270
271 // q3 = first chunk: q7 right-shifted by '16-len' bytes.
272 vmov.i8 q3, #0x80
273 veor.8 q2, q2, q3
274 vtbl.8 q3l, {q7l-q7h}, q2l
275 vtbl.8 q3h, {q7l-q7h}, q2h
276
277 // Convert to 8-bit masks: 'len' 0x00 bytes, then '16-len' 0xff bytes.
278 vshr.s8 q2, q2, #7
279
280 // q2 = second chunk: 'len' bytes from q0 (low-order bytes),
281 // then '16-len' bytes from q1 (high-order bytes).
282 vbsl.8 q2, q1, q0
283
284 // Fold the first chunk into the second chunk, storing the result in q7.
285 vmull.p64 q0, q3l, FOLD_CONST_L
286 vmull.p64 q7, q3h, FOLD_CONST_H
287 veor.8 q7, q7, q0
288 veor.8 q7, q7, q2
289
290 .Lreduce_final_16_bytes:
291 // Reduce the 128-bit value M(x), stored in q7, to the final 16-bit CRC.
292
293 // Load 'x^48 * (x^48 mod G(x))' and 'x^48 * (x^80 mod G(x))'.
294 vld1.64 {FOLD_CONSTS}, [fold_consts_ptr, :128]!
295
296 // Fold the high 64 bits into the low 64 bits, while also multiplying by
297 // x^64. This produces a 128-bit value congruent to x^64 * M(x) and
298 // whose low 48 bits are 0.
299 vmull.p64 q0, q7h, FOLD_CONST_H // high bits * x^48 * (x^80 mod G(x))
300 veor.8 q0h, q0h, q7l // + low bits * x^64
301
302 // Fold the high 32 bits into the low 96 bits. This produces a 96-bit
303 // value congruent to x^64 * M(x) and whose low 48 bits are 0.
304 vmov.i8 q1, #0
305 vmov s4, s3 // extract high 32 bits
306 vmov s3, s5 // zero high 32 bits
307 vmull.p64 q1, q1l, FOLD_CONST_L // high 32 bits * x^48 * (x^48 mod G(x))
308 veor.8 q0, q0, q1 // + low bits
309
310 // Load G(x) and floor(x^48 / G(x)).
311 vld1.64 {FOLD_CONSTS}, [fold_consts_ptr, :128]
312
313 // Use Barrett reduction to compute the final CRC value.
314 vmull.p64 q1, q0h, FOLD_CONST_H // high 32 bits * floor(x^48 / G(x))
315 vshr.u64 q1l, q1l, #32 // /= x^32
316 vmull.p64 q1, q1l, FOLD_CONST_L // *= G(x)
317 vshr.u64 q0l, q0l, #48
318 veor.8 q0l, q0l, q1l // + low 16 nonzero bits
319 // Final CRC value (x^16 * M(x)) mod G(x) is in low 16 bits of q0.
320
321 vmov.u16 r0, q0l[0]
322 bx lr
323
324 .Lless_than_256_bytes:
325 // Checksumming a buffer of length 16...255 bytes
326
327 __adrl fold_consts_ptr, .Lfold_across_16_bytes_consts
328
329 // Load the first 16 data bytes.
330 vld1.64 {q7}, [buf]!
331 CPU_LE( vrev64.8 q7, q7 )
332 vswp q7l, q7h
333
334 // XOR the first 16 data *bits* with the initial CRC value.
335 vmov.i8 q0h, #0
336 vmov.u16 q0h[3], init_crc
337 veor.8 q7h, q7h, q0h
338
339 // Load the fold-across-16-bytes constants.
340 vld1.64 {FOLD_CONSTS}, [fold_consts_ptr, :128]!
341
342 cmp len, #16
343 beq .Lreduce_final_16_bytes // len == 16
344 subs len, len, #32
345 addlt len, len, #16
346 blt .Lhandle_partial_segment // 17 <= len <= 31
347 b .Lfold_16_bytes_loop // 32 <= len <= 255
348 ENDPROC(crc_t10dif_pmull)
349
350 .section ".rodata", "a"
351 .align 4
352
353 // Fold constants precomputed from the polynomial 0x18bb7
354 // G(x) = x^16 + x^15 + x^11 + x^9 + x^8 + x^7 + x^5 + x^4 + x^2 + x^1 + x^0
355 .Lfold_across_128_bytes_consts:
356 .quad 0x0000000000006123 // x^(8*128) mod G(x)
357 .quad 0x0000000000002295 // x^(8*128+64) mod G(x)
358 // .Lfold_across_64_bytes_consts:
359 .quad 0x0000000000001069 // x^(4*128) mod G(x)
360 .quad 0x000000000000dd31 // x^(4*128+64) mod G(x)
361 // .Lfold_across_32_bytes_consts:
362 .quad 0x000000000000857d // x^(2*128) mod G(x)
363 .quad 0x0000000000007acc // x^(2*128+64) mod G(x)
364 .Lfold_across_16_bytes_consts:
365 .quad 0x000000000000a010 // x^(1*128) mod G(x)
366 .quad 0x0000000000001faa // x^(1*128+64) mod G(x)
367 // .Lfinal_fold_consts:
368 .quad 0x1368000000000000 // x^48 * (x^48 mod G(x))
369 .quad 0x2d56000000000000 // x^48 * (x^80 mod G(x))
370 // .Lbarrett_reduction_consts:
371 .quad 0x0000000000018bb7 // G(x)
372 .quad 0x00000001f65a57f8 // floor(x^48 / G(x))
373
374 // For 1 <= len <= 15, the 16-byte vector beginning at &byteshift_table[16 -
375 // len] is the index vector to shift left by 'len' bytes, and is also {0x80,
376 // ..., 0x80} XOR the index vector to shift right by '16 - len' bytes.
377 .Lbyteshift_table:
378 .byte 0x0, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87
379 .byte 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f
380 .byte 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7
381 .byte 0x8, 0x9, 0xa, 0xb, 0xc, 0xd, 0xe , 0x0