| /* |
| * Implement fast CRC32C with PCLMULQDQ instructions. (x86_64) |
| * |
| * The white papers on CRC32C calculations with PCLMULQDQ instruction can be |
| * downloaded from: |
| * http://www.intel.com/content/dam/www/public/us/en/documents/white-papers/crc-iscsi-polynomial-crc32-instruction-paper.pdf |
| * http://www.intel.com/content/dam/www/public/us/en/documents/white-papers/fast-crc-computation-paper.pdf |
| * |
| * Copyright (C) 2012 Intel Corporation. |
| * Copyright 2024 Google LLC |
| * |
| * Authors: |
| * Wajdi Feghali <wajdi.k.feghali@intel.com> |
| * James Guilford <james.guilford@intel.com> |
| * David Cote <david.m.cote@intel.com> |
| * Tim Chen <tim.c.chen@linux.intel.com> |
| * |
| * This software is available to you under a choice of one of two |
| * licenses. You may choose to be licensed under the terms of the GNU |
| * General Public License (GPL) Version 2, available from the file |
| * COPYING in the main directory of this source tree, or the |
| * OpenIB.org BSD license below: |
| * |
| * Redistribution and use in source and binary forms, with or |
| * without modification, are permitted provided that the following |
| * conditions are met: |
| * |
| * - Redistributions of source code must retain the above |
| * copyright notice, this list of conditions and the following |
| * disclaimer. |
| * |
| * - Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following |
| * disclaimer in the documentation and/or other materials |
| * provided with the distribution. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
| * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS |
| * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN |
| * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
| * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| * SOFTWARE. |
| */ |
| |
| #include <linux/linkage.h> |
| |
| ## ISCSI CRC 32 Implementation with crc32 and pclmulqdq Instruction |
| |
| # Define threshold below which buffers are considered "small" and routed to |
| # regular CRC code that does not interleave the CRC instructions. |
| #define SMALL_SIZE 200 |
| |
| # unsigned int crc_pcl(const u8 *buffer, unsigned int len, unsigned int crc_init); |
| |
| .text |
| SYM_FUNC_START(crc_pcl) |
| #define bufp %rdi |
| #define bufp_d %edi |
| #define len %esi |
| #define crc_init %edx |
| #define crc_init_q %rdx |
| #define n_misaligned %ecx /* overlaps chunk_bytes! */ |
| #define n_misaligned_q %rcx |
| #define chunk_bytes %ecx /* overlaps n_misaligned! */ |
| #define chunk_bytes_q %rcx |
| #define crc1 %r8 |
| #define crc2 %r9 |
| |
| cmp $SMALL_SIZE, len |
| jb .Lsmall |
| |
| ################################################################ |
| ## 1) ALIGN: |
| ################################################################ |
| mov bufp_d, n_misaligned |
| neg n_misaligned |
| and $7, n_misaligned # calculate the misalignment amount of |
| # the address |
| je .Laligned # Skip if aligned |
| |
| # Process 1 <= n_misaligned <= 7 bytes individually in order to align |
| # the remaining data to an 8-byte boundary. |
| .Ldo_align: |
| movq (bufp), %rax |
| add n_misaligned_q, bufp |
| sub n_misaligned, len |
| .Lalign_loop: |
| crc32b %al, crc_init # compute crc32 of 1-byte |
| shr $8, %rax # get next byte |
| dec n_misaligned |
| jne .Lalign_loop |
| .Laligned: |
| |
| ################################################################ |
| ## 2) PROCESS BLOCK: |
| ################################################################ |
| |
| cmp $128*24, len |
| jae .Lfull_block |
| |
| .Lpartial_block: |
| # Compute floor(len / 24) to get num qwords to process from each lane. |
| imul $2731, len, %eax # 2731 = ceil(2^16 / 24) |
| shr $16, %eax |
| jmp .Lcrc_3lanes |
| |
| .Lfull_block: |
| # Processing 128 qwords from each lane. |
| mov $128, %eax |
| |
| ################################################################ |
| ## 3) CRC each of three lanes: |
| ################################################################ |
| |
| .Lcrc_3lanes: |
| xor crc1,crc1 |
| xor crc2,crc2 |
| mov %eax, chunk_bytes |
| shl $3, chunk_bytes # num bytes to process from each lane |
| sub $5, %eax # 4 for 4x_loop, 1 for special last iter |
| jl .Lcrc_3lanes_4x_done |
| |
| # Unroll the loop by a factor of 4 to reduce the overhead of the loop |
| # bookkeeping instructions, which can compete with crc32q for the ALUs. |
| .Lcrc_3lanes_4x_loop: |
| crc32q (bufp), crc_init_q |
| crc32q (bufp,chunk_bytes_q), crc1 |
| crc32q (bufp,chunk_bytes_q,2), crc2 |
| crc32q 8(bufp), crc_init_q |
| crc32q 8(bufp,chunk_bytes_q), crc1 |
| crc32q 8(bufp,chunk_bytes_q,2), crc2 |
| crc32q 16(bufp), crc_init_q |
| crc32q 16(bufp,chunk_bytes_q), crc1 |
| crc32q 16(bufp,chunk_bytes_q,2), crc2 |
| crc32q 24(bufp), crc_init_q |
| crc32q 24(bufp,chunk_bytes_q), crc1 |
| crc32q 24(bufp,chunk_bytes_q,2), crc2 |
| add $32, bufp |
| sub $4, %eax |
| jge .Lcrc_3lanes_4x_loop |
| |
| .Lcrc_3lanes_4x_done: |
| add $4, %eax |
| jz .Lcrc_3lanes_last_qword |
| |
| .Lcrc_3lanes_1x_loop: |
| crc32q (bufp), crc_init_q |
| crc32q (bufp,chunk_bytes_q), crc1 |
| crc32q (bufp,chunk_bytes_q,2), crc2 |
| add $8, bufp |
| dec %eax |
| jnz .Lcrc_3lanes_1x_loop |
| |
| .Lcrc_3lanes_last_qword: |
| crc32q (bufp), crc_init_q |
| crc32q (bufp,chunk_bytes_q), crc1 |
| # SKIP crc32q (bufp,chunk_bytes_q,2), crc2 ; Don't do this one yet |
| |
| ################################################################ |
| ## 4) Combine three results: |
| ################################################################ |
| |
| lea (K_table-8)(%rip), %rax # first entry is for idx 1 |
| pmovzxdq (%rax,chunk_bytes_q), %xmm0 # 2 consts: K1:K2 |
| lea (chunk_bytes,chunk_bytes,2), %eax # chunk_bytes * 3 |
| sub %eax, len # len -= chunk_bytes * 3 |
| |
| movq crc_init_q, %xmm1 # CRC for block 1 |
| pclmulqdq $0x00, %xmm0, %xmm1 # Multiply by K2 |
| |
| movq crc1, %xmm2 # CRC for block 2 |
| pclmulqdq $0x10, %xmm0, %xmm2 # Multiply by K1 |
| |
| pxor %xmm2,%xmm1 |
| movq %xmm1, %rax |
| xor (bufp,chunk_bytes_q,2), %rax |
| mov crc2, crc_init_q |
| crc32 %rax, crc_init_q |
| lea 8(bufp,chunk_bytes_q,2), bufp |
| |
| ################################################################ |
| ## 5) If more blocks remain, goto (2): |
| ################################################################ |
| |
| cmp $128*24, len |
| jae .Lfull_block |
| cmp $SMALL_SIZE, len |
| jae .Lpartial_block |
| |
| ####################################################################### |
| ## 6) Process any remainder without interleaving: |
| ####################################################################### |
| .Lsmall: |
| test len, len |
| jz .Ldone |
| mov len, %eax |
| shr $3, %eax |
| jz .Ldo_dword |
| .Ldo_qwords: |
| crc32q (bufp), crc_init_q |
| add $8, bufp |
| dec %eax |
| jnz .Ldo_qwords |
| .Ldo_dword: |
| test $4, len |
| jz .Ldo_word |
| crc32l (bufp), crc_init |
| add $4, bufp |
| .Ldo_word: |
| test $2, len |
| jz .Ldo_byte |
| crc32w (bufp), crc_init |
| add $2, bufp |
| .Ldo_byte: |
| test $1, len |
| jz .Ldone |
| crc32b (bufp), crc_init |
| .Ldone: |
| mov crc_init, %eax |
| RET |
| SYM_FUNC_END(crc_pcl) |
| |
| .section .rodata, "a", @progbits |
| ################################################################ |
| ## PCLMULQDQ tables |
| ## Table is 128 entries x 2 words (8 bytes) each |
| ################################################################ |
| .align 8 |
| K_table: |
| .long 0x493c7d27, 0x00000001 |
| .long 0xba4fc28e, 0x493c7d27 |
| .long 0xddc0152b, 0xf20c0dfe |
| .long 0x9e4addf8, 0xba4fc28e |
| .long 0x39d3b296, 0x3da6d0cb |
| .long 0x0715ce53, 0xddc0152b |
| .long 0x47db8317, 0x1c291d04 |
| .long 0x0d3b6092, 0x9e4addf8 |
| .long 0xc96cfdc0, 0x740eef02 |
| .long 0x878a92a7, 0x39d3b296 |
| .long 0xdaece73e, 0x083a6eec |
| .long 0xab7aff2a, 0x0715ce53 |
| .long 0x2162d385, 0xc49f4f67 |
| .long 0x83348832, 0x47db8317 |
| .long 0x299847d5, 0x2ad91c30 |
| .long 0xb9e02b86, 0x0d3b6092 |
| .long 0x18b33a4e, 0x6992cea2 |
| .long 0xb6dd949b, 0xc96cfdc0 |
| .long 0x78d9ccb7, 0x7e908048 |
| .long 0xbac2fd7b, 0x878a92a7 |
| .long 0xa60ce07b, 0x1b3d8f29 |
| .long 0xce7f39f4, 0xdaece73e |
| .long 0x61d82e56, 0xf1d0f55e |
| .long 0xd270f1a2, 0xab7aff2a |
| .long 0xc619809d, 0xa87ab8a8 |
| .long 0x2b3cac5d, 0x2162d385 |
| .long 0x65863b64, 0x8462d800 |
| .long 0x1b03397f, 0x83348832 |
| .long 0xebb883bd, 0x71d111a8 |
| .long 0xb3e32c28, 0x299847d5 |
| .long 0x064f7f26, 0xffd852c6 |
| .long 0xdd7e3b0c, 0xb9e02b86 |
| .long 0xf285651c, 0xdcb17aa4 |
| .long 0x10746f3c, 0x18b33a4e |
| .long 0xc7a68855, 0xf37c5aee |
| .long 0x271d9844, 0xb6dd949b |
| .long 0x8e766a0c, 0x6051d5a2 |
| .long 0x93a5f730, 0x78d9ccb7 |
| .long 0x6cb08e5c, 0x18b0d4ff |
| .long 0x6b749fb2, 0xbac2fd7b |
| .long 0x1393e203, 0x21f3d99c |
| .long 0xcec3662e, 0xa60ce07b |
| .long 0x96c515bb, 0x8f158014 |
| .long 0xe6fc4e6a, 0xce7f39f4 |
| .long 0x8227bb8a, 0xa00457f7 |
| .long 0xb0cd4768, 0x61d82e56 |
| .long 0x39c7ff35, 0x8d6d2c43 |
| .long 0xd7a4825c, 0xd270f1a2 |
| .long 0x0ab3844b, 0x00ac29cf |
| .long 0x0167d312, 0xc619809d |
| .long 0xf6076544, 0xe9adf796 |
| .long 0x26f6a60a, 0x2b3cac5d |
| .long 0xa741c1bf, 0x96638b34 |
| .long 0x98d8d9cb, 0x65863b64 |
| .long 0x49c3cc9c, 0xe0e9f351 |
| .long 0x68bce87a, 0x1b03397f |
| .long 0x57a3d037, 0x9af01f2d |
| .long 0x6956fc3b, 0xebb883bd |
| .long 0x42d98888, 0x2cff42cf |
| .long 0x3771e98f, 0xb3e32c28 |
| .long 0xb42ae3d9, 0x88f25a3a |
| .long 0x2178513a, 0x064f7f26 |
| .long 0xe0ac139e, 0x4e36f0b0 |
| .long 0x170076fa, 0xdd7e3b0c |
| .long 0x444dd413, 0xbd6f81f8 |
| .long 0x6f345e45, 0xf285651c |
| .long 0x41d17b64, 0x91c9bd4b |
| .long 0xff0dba97, 0x10746f3c |
| .long 0xa2b73df1, 0x885f087b |
| .long 0xf872e54c, 0xc7a68855 |
| .long 0x1e41e9fc, 0x4c144932 |
| .long 0x86d8e4d2, 0x271d9844 |
| .long 0x651bd98b, 0x52148f02 |
| .long 0x5bb8f1bc, 0x8e766a0c |
| .long 0xa90fd27a, 0xa3c6f37a |
| .long 0xb3af077a, 0x93a5f730 |
| .long 0x4984d782, 0xd7c0557f |
| .long 0xca6ef3ac, 0x6cb08e5c |
| .long 0x234e0b26, 0x63ded06a |
| .long 0xdd66cbbb, 0x6b749fb2 |
| .long 0x4597456a, 0x4d56973c |
| .long 0xe9e28eb4, 0x1393e203 |
| .long 0x7b3ff57a, 0x9669c9df |
| .long 0xc9c8b782, 0xcec3662e |
| .long 0x3f70cc6f, 0xe417f38a |
| .long 0x93e106a4, 0x96c515bb |
| .long 0x62ec6c6d, 0x4b9e0f71 |
| .long 0xd813b325, 0xe6fc4e6a |
| .long 0x0df04680, 0xd104b8fc |
| .long 0x2342001e, 0x8227bb8a |
| .long 0x0a2a8d7e, 0x5b397730 |
| .long 0x6d9a4957, 0xb0cd4768 |
| .long 0xe8b6368b, 0xe78eb416 |
| .long 0xd2c3ed1a, 0x39c7ff35 |
| .long 0x995a5724, 0x61ff0e01 |
| .long 0x9ef68d35, 0xd7a4825c |
| .long 0x0c139b31, 0x8d96551c |
| .long 0xf2271e60, 0x0ab3844b |
| .long 0x0b0bf8ca, 0x0bf80dd2 |
| .long 0x2664fd8b, 0x0167d312 |
| .long 0xed64812d, 0x8821abed |
| .long 0x02ee03b2, 0xf6076544 |
| .long 0x8604ae0f, 0x6a45d2b2 |
| .long 0x363bd6b3, 0x26f6a60a |
| .long 0x135c83fd, 0xd8d26619 |
| .long 0x5fabe670, 0xa741c1bf |
| .long 0x35ec3279, 0xde87806c |
| .long 0x00bcf5f6, 0x98d8d9cb |
| .long 0x8ae00689, 0x14338754 |
| .long 0x17f27698, 0x49c3cc9c |
| .long 0x58ca5f00, 0x5bd2011f |
| .long 0xaa7c7ad5, 0x68bce87a |
| .long 0xb5cfca28, 0xdd07448e |
| .long 0xded288f8, 0x57a3d037 |
| .long 0x59f229bc, 0xdde8f5b9 |
| .long 0x6d390dec, 0x6956fc3b |
| .long 0x37170390, 0xa3e3e02c |
| .long 0x6353c1cc, 0x42d98888 |
| .long 0xc4584f5c, 0xd73c7bea |
| .long 0xf48642e9, 0x3771e98f |
| .long 0x531377e2, 0x80ff0093 |
| .long 0xdd35bc8d, 0xb42ae3d9 |
| .long 0xb25b29f2, 0x8fe4c34d |
| .long 0x9a5ede41, 0x2178513a |
| .long 0xa563905d, 0xdf99fc11 |
| .long 0x45cddf4e, 0xe0ac139e |
| .long 0xacfa3103, 0x6c23e841 |
| .long 0xa51b6135, 0x170076fa |
