/* GPL HEADER START
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 only,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 for more details (a copy is included
* in the LICENSE file that accompanied this code).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; If not, see http://www.gnu.org/licenses
*
* Please visit http://www.xyratex.com/contact if you need additional
* information or have any questions.
*
* GPL HEADER END
*/
/*
* Copyright 2012 Xyratex Technology Limited
*
* Using hardware provided PCLMULQDQ instruction to accelerate the CRC32
* calculation.
* CRC32 polynomial:0x04c11db7(BE)/0xEDB88320(LE)
* PCLMULQDQ is a new instruction in Intel SSE4.2, the reference can be found
* at:
* http://www.intel.com/products/processor/manuals/
* Intel(R) 64 and IA-32 Architectures Software Developer's Manual
* Volume 2B: Instruction Set Reference, N-Z
*
* Authors: Gregory Prestas <Gregory_Prestas@us.xyratex.com>
* Alexander Boyko <Alexander_Boyko@xyratex.com>
*/
#include <linux/linkage.h>
#include <asm/inst.h>
.section .rodata
.align 16
/*
* [x4*128+32 mod P(x) << 32)]' << 1 = 0x154442bd4
* #define CONSTANT_R1 0x154442bd4LL
*
* [(x4*128-32 mod P(x) << 32)]' << 1 = 0x1c6e41596
* #define CONSTANT_R2 0x1c6e41596LL
*/
.Lconstant_R2R1:
.octa 0x00000001c6e415960000000154442bd4
/*
* [(x128+32 mod P(x) << 32)]' << 1 = 0x1751997d0
* #define CONSTANT_R3 0x1751997d0LL
*
* [(x128-32 mod P(x) << 32)]' << 1 = 0x0ccaa009e
* #define CONSTANT_R4 0x0ccaa009eLL
*/
.Lconstant_R4R3:
.octa 0x00000000ccaa009e00000001751997d0
/*
* [(x64 mod P(x) << 32)]' << 1 = 0x163cd6124
* #define CONSTANT_R5 0x163cd6124LL
*/
.Lconstant_R5:
.octa 0x00000000000000000000000163cd6124
.Lconstant_mask32:
.octa 0x000000000000000000000000FFFFFFFF
/*
* #define CRCPOLY_TRUE_LE_FULL 0x1DB710641LL
*
* Barrett Reduction constant (u64`) = u` = (x**64 / P(x))` = 0x1F7011641LL
* #define CONSTANT_RU 0x1F7011641LL
*/
.Lconstant_RUpoly:
.octa 0x00000001F701164100000001DB710641
#define CONSTANT %xmm0
#ifdef __x86_64__
#define BUF %rdi
#define LEN %rsi
#define CRC %edx
#else
#define BUF %eax
#define LEN %edx
#define CRC %ecx
#endif
.text
/**
* Calculate crc32
* BUF - buffer (16 bytes aligned)
* LEN - sizeof buffer (16 bytes aligned), LEN should be grater than 63
* CRC - initial crc32
* return %eax crc32
* uint crc32_pclmul_le_16(unsigned char const *buffer,
* size_t len, uint crc32)
*/
ENTRY(crc32_pclmul_le_16) /* buffer and buffer size are 16 bytes aligned */
movdqa (BUF), %xmm1
movdqa 0x10(BUF), %xmm2
movdqa 0x20(BUF), %xmm3
movdqa 0x30(BUF), %xmm4
movd CRC, CONSTANT
pxor CONSTANT, %xmm1
sub $0x40, LEN
add $0x40, BUF
cmp $0x40, LEN
jb less_64
#ifdef __x86_64__
movdqa .Lconstant_R2R1(%rip), CONSTANT
#else
movdqa .Lconstant_R2R1, CONSTANT
#endif
loop_64:/* 64 bytes Full cache line folding */
prefetchnta 0x40(BUF)
movdqa %xmm1, %xmm5
movdqa %xmm2, %xmm6
movdqa %xmm3, %xmm7
#ifdef __x86_64__
movdqa %xmm4, %xmm8
#endif
PCLMULQDQ 00, CONSTANT, %xmm1
PCLMULQDQ 00, CONSTANT, %xmm2
PCLMULQDQ 00, CONSTANT, %xmm3
#ifdef __x86_64__
PCLMULQDQ 00, CONSTANT, %xmm4
#endif
PCLMULQDQ 0x11, CONSTANT, %xmm5
PCLMULQDQ 0x11, CONSTANT, %xmm6
PCLMULQDQ 0x11, CONSTANT, %xmm7
#ifdef __x86_64__
PCLMULQDQ 0x11, CONSTANT, %xmm8
#endif
pxor %xmm5, %xmm1
pxor %xmm6, %xmm2
pxor %xmm7, %xmm3
#ifdef __x86_64__
pxor %xmm8, %xmm4
#else
/* xmm8 unsupported for x32 */
movdqa %xmm4, %xmm5
PCLMULQDQ 00, CONSTANT, %xmm4
PCLMULQDQ 0x11, CONSTANT, %xmm5
pxor %xmm5, %xmm4
#endif
pxor (BUF), %xmm1
pxor 0x10(BUF), %xmm2
pxor 0x20(BUF), %xmm3
pxor 0x30(BUF), %xmm4
sub $0x40, LEN
add $0x40, BUF
cmp $0x40, LEN
jge loop_64
less_64:/* Folding cache line into 128bit */
#ifdef __x86_64__
movdqa .Lconstant_R4R3(%rip), CONSTANT
#else
movdqa .Lconstant_R4R3, CONSTANT
#endif
prefetchnta (BUF)
movdqa %xmm1, %xmm5
PCLMULQDQ 0x00, CONSTANT, %xmm1
PCLMULQDQ 0x11, CONSTANT, %xmm5
pxor %xmm5, %xmm1
pxor %xmm2, %xmm1
movdqa %xmm1, %xmm5
PCLMULQDQ 0x00, CONSTANT, %xmm1
PCLMULQDQ 0x11, CONSTANT, %xmm5
pxor %xmm5, %xmm1
pxor %xmm3, %xmm1
movdqa %xmm1, %xmm5
PCLMULQDQ 0x00, CONSTANT, %xmm1
PCLMULQDQ 0x11, CONSTANT, %xmm5
pxor %xmm5, %xmm1
pxor %xmm4, %xmm1
cmp $0x10, LEN
jb fold_64
loop_16:/* Folding rest buffer into 128bit */
movdqa %xmm1, %xmm5
PCLMULQDQ 0x00, CONSTANT, %xmm1
PCLMULQDQ 0x11, CONSTANT, %xmm5
pxor %xmm5, %xmm1
pxor (BUF), %xmm1
sub $0x10, LEN
add $0x10, BUF
cmp $0x10, LEN
jge loop_16
fold_64:
/* perform the last 64 bit fold, also adds 32 zeroes
* to the input stream */
PCLMULQDQ 0x01, %xmm1, CONSTANT /* R4 * xmm1.low */
psrldq $0x08, %xmm1
pxor CONSTANT, %xmm1
/* final 32-bit fold */
movdqa %xmm1, %xmm2
#ifdef __x86_64__
movdqa .Lconstant_R5(%rip), CONSTANT
movdqa .Lconstant_mask32(%rip), %xmm3
#else
movdqa .Lconstant_R5, CONSTANT
movdqa .Lconstant_mask32, %xmm3
#endif
psrldq $0x04, %xmm2
pand %xmm3, %xmm1
PCLMULQDQ 0x00, CONSTANT, %xmm1
pxor %xmm2, %xmm1
/* Finish up with the bit-reversed barrett reduction 64 ==> 32 bits */
#ifdef __x86_64__
movdqa .Lconstant_RUpoly(%rip), CONSTANT
#else
movdqa .Lconstant_RUpoly, CONSTANT
#endif
movdqa %xmm1, %xmm2
pand %xmm3, %xmm1
PCLMULQDQ 0x10, CONSTANT, %xmm1
pand %xmm3, %xmm1
PCLMULQDQ 0x00, CONSTANT, %xmm1
pxor %xmm2, %xmm1
PEXTRD 0x01, %xmm1, %eax
ret
ENDPROC(crc32_pclmul_le_16)