2 * Implement fast CRC32C with PCLMULQDQ instructions. (x86_64)
4 * The white papers on CRC32C calculations with PCLMULQDQ instruction can be
6 * http://www.intel.com/content/dam/www/public/us/en/documents/white-papers/crc-iscsi-polynomial-crc32-instruction-paper.pdf
7 * http://www.intel.com/content/dam/www/public/us/en/documents/white-papers/fast-crc-computation-paper.pdf
9 * Copyright (C) 2012 Intel Corporation.
12 * Wajdi Feghali <wajdi.k.feghali@intel.com>
13 * James Guilford <james.guilford@intel.com>
14 * David Cote <david.m.cote@intel.com>
15 * Tim Chen <tim.c.chen@linux.intel.com>
17 * This software is available to you under a choice of one of two
18 * licenses. You may choose to be licensed under the terms of the GNU
19 * General Public License (GPL) Version 2, available from the file
20 * COPYING in the main directory of this source tree, or the
21 * OpenIB.org BSD license below:
23 * Redistribution and use in source and binary forms, with or
24 * without modification, are permitted provided that the following
27 * - Redistributions of source code must retain the above
28 * copyright notice, this list of conditions and the following
31 * - Redistributions in binary form must reproduce the above
32 * copyright notice, this list of conditions and the following
33 * disclaimer in the documentation and/or other materials
34 * provided with the distribution.
36 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
37 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
38 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
39 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
40 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
41 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
42 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
46 #include <linux/linkage.h>
48 ## ISCSI CRC 32 Implementation with crc32 and pclmulqdq Instruction
55 .word crc_\i - crc_array
58 .macro JNC_LESS_THAN j
62 # Define threshold where buffers are considered "small" and routed to more
63 # efficient "by-1" code. This "by-1" code only handles up to 255 bytes, so
64 # SMALL_SIZE can be no larger than 255.
66 #define SMALL_SIZE 200
68 .if (SMALL_SIZE > 255)
69 .error "SMALL_ SIZE must be < 256"
72 # unsigned int crc_pcl(u8 *buffer, int len, unsigned int crc_init);
87 #define crc_init_arg %rdx
90 #define crc_init_dw %r8d
98 ## Move crc_init for Linux to a different
99 mov crc_init_arg, crc_init
101 ################################################################
103 ################################################################
105 mov bufp, bufptmp # rdi = *buf
107 and $7, bufp # calculate the unalignment amount of
109 je proc_block # Skip if aligned
111 ## If len is less than 8 and we're unaligned, we need to jump
112 ## to special code to avoid reading beyond the end of the buffer
115 # less_than_8 expects length in upper 3 bits of len_dw
116 # less_than_8_post_shl1 expects length = carryflag * 8 + len_dw[31:30]
118 jmp less_than_8_post_shl1
121 #### Calculate CRC of unaligned bytes of the buffer (if any)
122 movq (bufptmp), tmp # load a quadward from the buffer
123 add bufp, bufptmp # align buffer pointer for quadword
125 sub bufp, len # update buffer length
127 crc32b %bl, crc_init_dw # compute crc32 of 1-byte
128 shr $8, tmp # get next byte
134 ################################################################
135 ## 2) PROCESS BLOCKS:
136 ################################################################
138 ## compute num of bytes to be processed
139 movq len, tmp # save num bytes in tmp
145 cmpq $SMALL_SIZE, len
149 movq $2731, %rax # 2731 = ceil(2^16 / 24)
153 ## eax contains floor(bytes / 24) = num 24-byte chunks to do
155 ## process rax 24-byte chunks (128 >= rax >= 0)
157 ## compute end address of each block
158 ## block 0 (base addr + RAX * 8)
159 ## block 1 (base addr + RAX * 16)
160 ## block 2 (base addr + RAX * 24)
161 lea (bufptmp, %rax, 8), block_0
162 lea (block_0, %rax, 8), block_1
163 lea (block_1, %rax, 8), block_2
169 lea jump_table(%rip), bufp
170 movzxw (bufp, %rax, 2), len
171 offset=crc_array-jump_table
172 lea offset(bufp, len, 1), bufp
175 ################################################################
176 ## 2a) PROCESS FULL BLOCKS:
177 ################################################################
180 lea 128*8*2(block_0), block_1
181 lea 128*8*3(block_0), block_2
182 add $128*8*1, block_0
187 # Fall thruogh into top of crc array (crc_128)
189 ################################################################
191 ################################################################
199 crc32q -i*8(block_0), crc_init
200 crc32q -i*8(block_1), crc1
201 crc32q -i*8(block_2), crc2
208 crc32q -i*8(block_0), crc_init
209 crc32q -i*8(block_1), crc1
210 # SKIP crc32 -i*8(block_2), crc2 ; Don't do this one yet
214 ################################################################
215 ## 4) Combine three results:
216 ################################################################
218 lea (K_table-16)(%rip), bufp # first entry is for idx 1
219 shlq $3, %rax # rax *= 8
220 subq %rax, tmp # tmp -= rax*8
222 subq %rax, tmp # tmp -= rax*16
223 # (total tmp -= rax*24)
226 movdqa (bufp), %xmm0 # 2 consts: K1:K2
228 movq crc_init, %xmm1 # CRC for block 1
229 pclmulqdq $0x00,%xmm0,%xmm1 # Multiply by K2
231 movq crc1, %xmm2 # CRC for block 2
232 pclmulqdq $0x10, %xmm0, %xmm2 # Multiply by K1
236 xor -i*8(block_2), %rax
240 ################################################################
242 ################################################################
252 shl $32-4, len_dw # less_than_16 expects length
253 # in upper 4 bits of len_dw
255 crc32q (bufptmp), crc_init
256 crc32q 8(bufptmp), crc_init
259 # len is less than 8 if we got here
260 # less_than_8 expects length in upper 3 bits of len_dw
261 # less_than_8_post_shl1 expects length = carryflag * 8 + len_dw[31:30]
263 jmp less_than_8_post_shl1
265 #######################################################################
266 ## 6) LESS THAN 256-bytes REMAIN AT THIS POINT (8-bits of len are full)
267 #######################################################################
269 shl $32-8, len_dw # Prepare len_dw for less_than_256
271 .rept 5 # j = {256, 128, 64, 32, 16}
273 LABEL less_than_ %j # less_than_j: Length should be in
274 # upper lg(j) bits of len_dw
276 shl $1, len_dw # Get next MSB
281 crc32q i(bufptmp), crc_init # Compute crc32 of 8-byte data
284 jz do_return # Return if remaining length is zero
285 add $j, bufptmp # Advance buf
288 less_than_8: # Length should be stored in
289 # upper 3 bits of len_dw
291 less_than_8_post_shl1:
293 crc32l (bufptmp), crc_init_dw # CRC of 4 bytes
294 jz do_return # return if remaining data is zero
296 less_than_4: # Length should be stored in
297 # upper 2 bits of len_dw
300 crc32w (bufptmp), crc_init_dw # CRC of 2 bytes
301 jz do_return # return if remaining data is zero
303 less_than_2: # Length should be stored in the MSB
307 crc32b (bufptmp), crc_init_dw # CRC of 1 byte
308 less_than_1: # Length should be zero
316 ################################################################
317 ## jump table Table is 129 entries x 2 bytes each
318 ################################################################
331 ################################################################
333 ## Table is 128 entries x 2 quad words each
334 ################################################################
338 .quad 0x14cd00bd6,0x105ec76f0
339 .quad 0x0ba4fc28e,0x14cd00bd6
340 .quad 0x1d82c63da,0x0f20c0dfe
341 .quad 0x09e4addf8,0x0ba4fc28e
342 .quad 0x039d3b296,0x1384aa63a
343 .quad 0x102f9b8a2,0x1d82c63da
344 .quad 0x14237f5e6,0x01c291d04
345 .quad 0x00d3b6092,0x09e4addf8
346 .quad 0x0c96cfdc0,0x0740eef02
347 .quad 0x18266e456,0x039d3b296
348 .quad 0x0daece73e,0x0083a6eec
349 .quad 0x0ab7aff2a,0x102f9b8a2
350 .quad 0x1248ea574,0x1c1733996
351 .quad 0x083348832,0x14237f5e6
352 .quad 0x12c743124,0x02ad91c30
353 .quad 0x0b9e02b86,0x00d3b6092
354 .quad 0x018b33a4e,0x06992cea2
355 .quad 0x1b331e26a,0x0c96cfdc0
356 .quad 0x17d35ba46,0x07e908048
357 .quad 0x1bf2e8b8a,0x18266e456
358 .quad 0x1a3e0968a,0x11ed1f9d8
359 .quad 0x0ce7f39f4,0x0daece73e
360 .quad 0x061d82e56,0x0f1d0f55e
361 .quad 0x0d270f1a2,0x0ab7aff2a
362 .quad 0x1c3f5f66c,0x0a87ab8a8
363 .quad 0x12ed0daac,0x1248ea574
364 .quad 0x065863b64,0x08462d800
365 .quad 0x11eef4f8e,0x083348832
366 .quad 0x1ee54f54c,0x071d111a8
367 .quad 0x0b3e32c28,0x12c743124
368 .quad 0x0064f7f26,0x0ffd852c6
369 .quad 0x0dd7e3b0c,0x0b9e02b86
370 .quad 0x0f285651c,0x0dcb17aa4
371 .quad 0x010746f3c,0x018b33a4e
372 .quad 0x1c24afea4,0x0f37c5aee
373 .quad 0x0271d9844,0x1b331e26a
374 .quad 0x08e766a0c,0x06051d5a2
375 .quad 0x093a5f730,0x17d35ba46
376 .quad 0x06cb08e5c,0x11d5ca20e
377 .quad 0x06b749fb2,0x1bf2e8b8a
378 .quad 0x1167f94f2,0x021f3d99c
379 .quad 0x0cec3662e,0x1a3e0968a
380 .quad 0x19329634a,0x08f158014
381 .quad 0x0e6fc4e6a,0x0ce7f39f4
382 .quad 0x08227bb8a,0x1a5e82106
383 .quad 0x0b0cd4768,0x061d82e56
384 .quad 0x13c2b89c4,0x188815ab2
385 .quad 0x0d7a4825c,0x0d270f1a2
386 .quad 0x10f5ff2ba,0x105405f3e
387 .quad 0x00167d312,0x1c3f5f66c
388 .quad 0x0f6076544,0x0e9adf796
389 .quad 0x026f6a60a,0x12ed0daac
390 .quad 0x1a2adb74e,0x096638b34
391 .quad 0x19d34af3a,0x065863b64
392 .quad 0x049c3cc9c,0x1e50585a0
393 .quad 0x068bce87a,0x11eef4f8e
394 .quad 0x1524fa6c6,0x19f1c69dc
395 .quad 0x16cba8aca,0x1ee54f54c
396 .quad 0x042d98888,0x12913343e
397 .quad 0x1329d9f7e,0x0b3e32c28
398 .quad 0x1b1c69528,0x088f25a3a
399 .quad 0x02178513a,0x0064f7f26
400 .quad 0x0e0ac139e,0x04e36f0b0
401 .quad 0x0170076fa,0x0dd7e3b0c
402 .quad 0x141a1a2e2,0x0bd6f81f8
403 .quad 0x16ad828b4,0x0f285651c
404 .quad 0x041d17b64,0x19425cbba
405 .quad 0x1fae1cc66,0x010746f3c
406 .quad 0x1a75b4b00,0x18db37e8a
407 .quad 0x0f872e54c,0x1c24afea4
408 .quad 0x01e41e9fc,0x04c144932
409 .quad 0x086d8e4d2,0x0271d9844
410 .quad 0x160f7af7a,0x052148f02
411 .quad 0x05bb8f1bc,0x08e766a0c
412 .quad 0x0a90fd27a,0x0a3c6f37a
413 .quad 0x0b3af077a,0x093a5f730
414 .quad 0x04984d782,0x1d22c238e
415 .quad 0x0ca6ef3ac,0x06cb08e5c
416 .quad 0x0234e0b26,0x063ded06a
417 .quad 0x1d88abd4a,0x06b749fb2
418 .quad 0x04597456a,0x04d56973c
419 .quad 0x0e9e28eb4,0x1167f94f2
420 .quad 0x07b3ff57a,0x19385bf2e
421 .quad 0x0c9c8b782,0x0cec3662e
422 .quad 0x13a9cba9e,0x0e417f38a
423 .quad 0x093e106a4,0x19329634a
424 .quad 0x167001a9c,0x14e727980
425 .quad 0x1ddffc5d4,0x0e6fc4e6a
426 .quad 0x00df04680,0x0d104b8fc
427 .quad 0x02342001e,0x08227bb8a
428 .quad 0x00a2a8d7e,0x05b397730
429 .quad 0x168763fa6,0x0b0cd4768
430 .quad 0x1ed5a407a,0x0e78eb416
431 .quad 0x0d2c3ed1a,0x13c2b89c4
432 .quad 0x0995a5724,0x1641378f0
433 .quad 0x19b1afbc4,0x0d7a4825c
434 .quad 0x109ffedc0,0x08d96551c
435 .quad 0x0f2271e60,0x10f5ff2ba
436 .quad 0x00b0bf8ca,0x00bf80dd2
437 .quad 0x123888b7a,0x00167d312
438 .quad 0x1e888f7dc,0x18dcddd1c
439 .quad 0x002ee03b2,0x0f6076544
440 .quad 0x183e8d8fe,0x06a45d2b2
441 .quad 0x133d7a042,0x026f6a60a
442 .quad 0x116b0f50c,0x1dd3e10e8
443 .quad 0x05fabe670,0x1a2adb74e
444 .quad 0x130004488,0x0de87806c
445 .quad 0x000bcf5f6,0x19d34af3a
446 .quad 0x18f0c7078,0x014338754
447 .quad 0x017f27698,0x049c3cc9c
448 .quad 0x058ca5f00,0x15e3e77ee
449 .quad 0x1af900c24,0x068bce87a
450 .quad 0x0b5cfca28,0x0dd07448e
451 .quad 0x0ded288f8,0x1524fa6c6
452 .quad 0x059f229bc,0x1d8048348
453 .quad 0x06d390dec,0x16cba8aca
454 .quad 0x037170390,0x0a3e3e02c
455 .quad 0x06353c1cc,0x042d98888
456 .quad 0x0c4584f5c,0x0d73c7bea
457 .quad 0x1f16a3418,0x1329d9f7e
458 .quad 0x0531377e2,0x185137662
459 .quad 0x1d8d9ca7c,0x1b1c69528
460 .quad 0x0b25b29f2,0x18a08b5bc
461 .quad 0x19fb2a8b0,0x02178513a
462 .quad 0x1a08fe6ac,0x1da758ae0
463 .quad 0x045cddf4e,0x0e0ac139e
464 .quad 0x1a91647f2,0x169cf9eb0
465 .quad 0x1a0f717c4,0x0170076fa