1/* 2 * Implement fast CRC32C with PCLMULQDQ instructions. (x86_64) 3 * 4 * The white papers on CRC32C calculations with PCLMULQDQ instruction can be 5 * downloaded from: 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 8 * 9 * Copyright (C) 2012 Intel Corporation. 10 * 11 * Authors: 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> 16 * 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: 22 * 23 * Redistribution and use in source and binary forms, with or 24 * without modification, are permitted provided that the following 25 * conditions are met: 26 * 27 * - Redistributions of source code must retain the above 28 * copyright notice, this list of conditions and the following 29 * disclaimer. 30 * 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. 35 * 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 43 * SOFTWARE. 44 */ 45 46#include <linux/linkage.h> 47#include <asm/nospec-branch.h> 48 49## ISCSI CRC 32 Implementation with crc32 and pclmulqdq Instruction 50 51.macro LABEL prefix n 52\prefix\n\(): 53.endm 54 55.macro JMPTBL_ENTRY i 56.quad crc_\i 57.endm 58 59.macro JNC_LESS_THAN j 60 jnc less_than_\j 61.endm 62 63# Define threshold where buffers are considered "small" and routed to more 64# efficient "by-1" code. This "by-1" code only handles up to 255 bytes, so 65# SMALL_SIZE can be no larger than 255. 66 67#define SMALL_SIZE 200 68 69.if (SMALL_SIZE > 255) 70.error "SMALL_ SIZE must be < 256" 71.endif 72 73# unsigned int crc_pcl(u8 *buffer, int len, unsigned int crc_init); 74 75.text 76SYM_FUNC_START(crc_pcl) 77#define bufp rdi 78#define bufp_dw %edi 79#define bufp_w %di 80#define bufp_b %dil 81#define bufptmp %rcx 82#define block_0 %rcx 83#define block_1 %rdx 84#define block_2 %r11 85#define len %rsi 86#define len_dw %esi 87#define len_w %si 88#define len_b %sil 89#define crc_init_arg %rdx 90#define tmp %rbx 91#define crc_init %r8 92#define crc_init_dw %r8d 93#define crc1 %r9 94#define crc2 %r10 95 96 pushq %rbx 97 pushq %rdi 98 pushq %rsi 99 100 ## Move crc_init for Linux to a different 101 mov crc_init_arg, crc_init 102 103 ################################################################ 104 ## 1) ALIGN: 105 ################################################################ 106 107 mov %bufp, bufptmp # rdi = *buf 108 neg %bufp 109 and $7, %bufp # calculate the unalignment amount of 110 # the address 111 je proc_block # Skip if aligned 112 113 ## If len is less than 8 and we're unaligned, we need to jump 114 ## to special code to avoid reading beyond the end of the buffer 115 cmp $8, len 116 jae do_align 117 # less_than_8 expects length in upper 3 bits of len_dw 118 # less_than_8_post_shl1 expects length = carryflag * 8 + len_dw[31:30] 119 shl $32-3+1, len_dw 120 jmp less_than_8_post_shl1 121 122do_align: 123 #### Calculate CRC of unaligned bytes of the buffer (if any) 124 movq (bufptmp), tmp # load a quadward from the buffer 125 add %bufp, bufptmp # align buffer pointer for quadword 126 # processing 127 sub %bufp, len # update buffer length 128align_loop: 129 crc32b %bl, crc_init_dw # compute crc32 of 1-byte 130 shr $8, tmp # get next byte 131 dec %bufp 132 jne align_loop 133 134proc_block: 135 136 ################################################################ 137 ## 2) PROCESS BLOCKS: 138 ################################################################ 139 140 ## compute num of bytes to be processed 141 movq len, tmp # save num bytes in tmp 142 143 cmpq $128*24, len 144 jae full_block 145 146continue_block: 147 cmpq $SMALL_SIZE, len 148 jb small 149 150 ## len < 128*24 151 movq $2731, %rax # 2731 = ceil(2^16 / 24) 152 mul len_dw 153 shrq $16, %rax 154 155 ## eax contains floor(bytes / 24) = num 24-byte chunks to do 156 157 ## process rax 24-byte chunks (128 >= rax >= 0) 158 159 ## compute end address of each block 160 ## block 0 (base addr + RAX * 8) 161 ## block 1 (base addr + RAX * 16) 162 ## block 2 (base addr + RAX * 24) 163 lea (bufptmp, %rax, 8), block_0 164 lea (block_0, %rax, 8), block_1 165 lea (block_1, %rax, 8), block_2 166 167 xor crc1, crc1 168 xor crc2, crc2 169 170 ## branch into array 171 mov jump_table(,%rax,8), %bufp 172 JMP_NOSPEC bufp 173 174 ################################################################ 175 ## 2a) PROCESS FULL BLOCKS: 176 ################################################################ 177full_block: 178 movl $128,%eax 179 lea 128*8*2(block_0), block_1 180 lea 128*8*3(block_0), block_2 181 add $128*8*1, block_0 182 183 xor crc1,crc1 184 xor crc2,crc2 185 186 # Fall thruogh into top of crc array (crc_128) 187 188 ################################################################ 189 ## 3) CRC Array: 190 ################################################################ 191 192crc_array: 193 i=128 194.rept 128-1 195.altmacro 196LABEL crc_ %i 197.noaltmacro 198 crc32q -i*8(block_0), crc_init 199 crc32q -i*8(block_1), crc1 200 crc32q -i*8(block_2), crc2 201 i=(i-1) 202.endr 203 204.altmacro 205LABEL crc_ %i 206.noaltmacro 207 crc32q -i*8(block_0), crc_init 208 crc32q -i*8(block_1), crc1 209# SKIP crc32 -i*8(block_2), crc2 ; Don't do this one yet 210 211 mov block_2, block_0 212 213 ################################################################ 214 ## 4) Combine three results: 215 ################################################################ 216 217 lea (K_table-8)(%rip), %bufp # first entry is for idx 1 218 shlq $3, %rax # rax *= 8 219 pmovzxdq (%bufp,%rax), %xmm0 # 2 consts: K1:K2 220 leal (%eax,%eax,2), %eax # rax *= 3 (total *24) 221 subq %rax, tmp # tmp -= rax*24 222 223 movq crc_init, %xmm1 # CRC for block 1 224 pclmulqdq $0x00, %xmm0, %xmm1 # Multiply by K2 225 226 movq crc1, %xmm2 # CRC for block 2 227 pclmulqdq $0x10, %xmm0, %xmm2 # Multiply by K1 228 229 pxor %xmm2,%xmm1 230 movq %xmm1, %rax 231 xor -i*8(block_2), %rax 232 mov crc2, crc_init 233 crc32 %rax, crc_init 234 235 ################################################################ 236 ## 5) Check for end: 237 ################################################################ 238 239LABEL crc_ 0 240 mov tmp, len 241 cmp $128*24, tmp 242 jae full_block 243 cmp $24, tmp 244 jae continue_block 245 246less_than_24: 247 shl $32-4, len_dw # less_than_16 expects length 248 # in upper 4 bits of len_dw 249 jnc less_than_16 250 crc32q (bufptmp), crc_init 251 crc32q 8(bufptmp), crc_init 252 jz do_return 253 add $16, bufptmp 254 # len is less than 8 if we got here 255 # less_than_8 expects length in upper 3 bits of len_dw 256 # less_than_8_post_shl1 expects length = carryflag * 8 + len_dw[31:30] 257 shl $2, len_dw 258 jmp less_than_8_post_shl1 259 260 ####################################################################### 261 ## 6) LESS THAN 256-bytes REMAIN AT THIS POINT (8-bits of len are full) 262 ####################################################################### 263small: 264 shl $32-8, len_dw # Prepare len_dw for less_than_256 265 j=256 266.rept 5 # j = {256, 128, 64, 32, 16} 267.altmacro 268LABEL less_than_ %j # less_than_j: Length should be in 269 # upper lg(j) bits of len_dw 270 j=(j/2) 271 shl $1, len_dw # Get next MSB 272 JNC_LESS_THAN %j 273.noaltmacro 274 i=0 275.rept (j/8) 276 crc32q i(bufptmp), crc_init # Compute crc32 of 8-byte data 277 i=i+8 278.endr 279 jz do_return # Return if remaining length is zero 280 add $j, bufptmp # Advance buf 281.endr 282 283less_than_8: # Length should be stored in 284 # upper 3 bits of len_dw 285 shl $1, len_dw 286less_than_8_post_shl1: 287 jnc less_than_4 288 crc32l (bufptmp), crc_init_dw # CRC of 4 bytes 289 jz do_return # return if remaining data is zero 290 add $4, bufptmp 291less_than_4: # Length should be stored in 292 # upper 2 bits of len_dw 293 shl $1, len_dw 294 jnc less_than_2 295 crc32w (bufptmp), crc_init_dw # CRC of 2 bytes 296 jz do_return # return if remaining data is zero 297 add $2, bufptmp 298less_than_2: # Length should be stored in the MSB 299 # of len_dw 300 shl $1, len_dw 301 jnc less_than_1 302 crc32b (bufptmp), crc_init_dw # CRC of 1 byte 303less_than_1: # Length should be zero 304do_return: 305 movq crc_init, %rax 306 popq %rsi 307 popq %rdi 308 popq %rbx 309 ret 310SYM_FUNC_END(crc_pcl) 311 312.section .rodata, "a", @progbits 313 ################################################################ 314 ## jump table Table is 129 entries x 2 bytes each 315 ################################################################ 316.align 4 317jump_table: 318 i=0 319.rept 129 320.altmacro 321JMPTBL_ENTRY %i 322.noaltmacro 323 i=i+1 324.endr 325 326 327 ################################################################ 328 ## PCLMULQDQ tables 329 ## Table is 128 entries x 2 words (8 bytes) each 330 ################################################################ 331.align 8 332K_table: 333 .long 0x493c7d27, 0x00000001 334 .long 0xba4fc28e, 0x493c7d27 335 .long 0xddc0152b, 0xf20c0dfe 336 .long 0x9e4addf8, 0xba4fc28e 337 .long 0x39d3b296, 0x3da6d0cb 338 .long 0x0715ce53, 0xddc0152b 339 .long 0x47db8317, 0x1c291d04 340 .long 0x0d3b6092, 0x9e4addf8 341 .long 0xc96cfdc0, 0x740eef02 342 .long 0x878a92a7, 0x39d3b296 343 .long 0xdaece73e, 0x083a6eec 344 .long 0xab7aff2a, 0x0715ce53 345 .long 0x2162d385, 0xc49f4f67 346 .long 0x83348832, 0x47db8317 347 .long 0x299847d5, 0x2ad91c30 348 .long 0xb9e02b86, 0x0d3b6092 349 .long 0x18b33a4e, 0x6992cea2 350 .long 0xb6dd949b, 0xc96cfdc0 351 .long 0x78d9ccb7, 0x7e908048 352 .long 0xbac2fd7b, 0x878a92a7 353 .long 0xa60ce07b, 0x1b3d8f29 354 .long 0xce7f39f4, 0xdaece73e 355 .long 0x61d82e56, 0xf1d0f55e 356 .long 0xd270f1a2, 0xab7aff2a 357 .long 0xc619809d, 0xa87ab8a8 358 .long 0x2b3cac5d, 0x2162d385 359 .long 0x65863b64, 0x8462d800 360 .long 0x1b03397f, 0x83348832 361 .long 0xebb883bd, 0x71d111a8 362 .long 0xb3e32c28, 0x299847d5 363 .long 0x064f7f26, 0xffd852c6 364 .long 0xdd7e3b0c, 0xb9e02b86 365 .long 0xf285651c, 0xdcb17aa4 366 .long 0x10746f3c, 0x18b33a4e 367 .long 0xc7a68855, 0xf37c5aee 368 .long 0x271d9844, 0xb6dd949b 369 .long 0x8e766a0c, 0x6051d5a2 370 .long 0x93a5f730, 0x78d9ccb7 371 .long 0x6cb08e5c, 0x18b0d4ff 372 .long 0x6b749fb2, 0xbac2fd7b 373 .long 0x1393e203, 0x21f3d99c 374 .long 0xcec3662e, 0xa60ce07b 375 .long 0x96c515bb, 0x8f158014 376 .long 0xe6fc4e6a, 0xce7f39f4 377 .long 0x8227bb8a, 0xa00457f7 378 .long 0xb0cd4768, 0x61d82e56 379 .long 0x39c7ff35, 0x8d6d2c43 380 .long 0xd7a4825c, 0xd270f1a2 381 .long 0x0ab3844b, 0x00ac29cf 382 .long 0x0167d312, 0xc619809d 383 .long 0xf6076544, 0xe9adf796 384 .long 0x26f6a60a, 0x2b3cac5d 385 .long 0xa741c1bf, 0x96638b34 386 .long 0x98d8d9cb, 0x65863b64 387 .long 0x49c3cc9c, 0xe0e9f351 388 .long 0x68bce87a, 0x1b03397f 389 .long 0x57a3d037, 0x9af01f2d 390 .long 0x6956fc3b, 0xebb883bd 391 .long 0x42d98888, 0x2cff42cf 392 .long 0x3771e98f, 0xb3e32c28 393 .long 0xb42ae3d9, 0x88f25a3a 394 .long 0x2178513a, 0x064f7f26 395 .long 0xe0ac139e, 0x4e36f0b0 396 .long 0x170076fa, 0xdd7e3b0c 397 .long 0x444dd413, 0xbd6f81f8 398 .long 0x6f345e45, 0xf285651c 399 .long 0x41d17b64, 0x91c9bd4b 400 .long 0xff0dba97, 0x10746f3c 401 .long 0xa2b73df1, 0x885f087b 402 .long 0xf872e54c, 0xc7a68855 403 .long 0x1e41e9fc, 0x4c144932 404 .long 0x86d8e4d2, 0x271d9844 405 .long 0x651bd98b, 0x52148f02 406 .long 0x5bb8f1bc, 0x8e766a0c 407 .long 0xa90fd27a, 0xa3c6f37a 408 .long 0xb3af077a, 0x93a5f730 409 .long 0x4984d782, 0xd7c0557f 410 .long 0xca6ef3ac, 0x6cb08e5c 411 .long 0x234e0b26, 0x63ded06a 412 .long 0xdd66cbbb, 0x6b749fb2 413 .long 0x4597456a, 0x4d56973c 414 .long 0xe9e28eb4, 0x1393e203 415 .long 0x7b3ff57a, 0x9669c9df 416 .long 0xc9c8b782, 0xcec3662e 417 .long 0x3f70cc6f, 0xe417f38a 418 .long 0x93e106a4, 0x96c515bb 419 .long 0x62ec6c6d, 0x4b9e0f71 420 .long 0xd813b325, 0xe6fc4e6a 421 .long 0x0df04680, 0xd104b8fc 422 .long 0x2342001e, 0x8227bb8a 423 .long 0x0a2a8d7e, 0x5b397730 424 .long 0x6d9a4957, 0xb0cd4768 425 .long 0xe8b6368b, 0xe78eb416 426 .long 0xd2c3ed1a, 0x39c7ff35 427 .long 0x995a5724, 0x61ff0e01 428 .long 0x9ef68d35, 0xd7a4825c 429 .long 0x0c139b31, 0x8d96551c 430 .long 0xf2271e60, 0x0ab3844b 431 .long 0x0b0bf8ca, 0x0bf80dd2 432 .long 0x2664fd8b, 0x0167d312 433 .long 0xed64812d, 0x8821abed 434 .long 0x02ee03b2, 0xf6076544 435 .long 0x8604ae0f, 0x6a45d2b2 436 .long 0x363bd6b3, 0x26f6a60a 437 .long 0x135c83fd, 0xd8d26619 438 .long 0x5fabe670, 0xa741c1bf 439 .long 0x35ec3279, 0xde87806c 440 .long 0x00bcf5f6, 0x98d8d9cb 441 .long 0x8ae00689, 0x14338754 442 .long 0x17f27698, 0x49c3cc9c 443 .long 0x58ca5f00, 0x5bd2011f 444 .long 0xaa7c7ad5, 0x68bce87a 445 .long 0xb5cfca28, 0xdd07448e 446 .long 0xded288f8, 0x57a3d037 447 .long 0x59f229bc, 0xdde8f5b9 448 .long 0x6d390dec, 0x6956fc3b 449 .long 0x37170390, 0xa3e3e02c 450 .long 0x6353c1cc, 0x42d98888 451 .long 0xc4584f5c, 0xd73c7bea 452 .long 0xf48642e9, 0x3771e98f 453 .long 0x531377e2, 0x80ff0093 454 .long 0xdd35bc8d, 0xb42ae3d9 455 .long 0xb25b29f2, 0x8fe4c34d 456 .long 0x9a5ede41, 0x2178513a 457 .long 0xa563905d, 0xdf99fc11 458 .long 0x45cddf4e, 0xe0ac139e 459 .long 0xacfa3103, 0x6c23e841 460 .long 0xa51b6135, 0x170076fa 461