/*
* Accelerated CRC32(C) using ARM CRC, NEON and Crypto Extensions instructions
*
* Copyright (C) 2016 Linaro Ltd <[email protected]>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
/* 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:
* https://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 <[email protected]>
* Alexander Boyko <[email protected]>
*/
#include <linux/linkage.h>
#include <linux/cfi_types.h>
#include <asm/assembler.h>
.text
.align 6
.arch armv8-a
.arch_extension crc
.fpu crypto-neon-fp-armv8
.Lcrc32_constants:
/*
* [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
*/
.quad 0x0000000154442bd4
.quad 0x00000001c6e41596
/*
* [(x128+32 mod P(x) << 32)]' << 1 = 0x1751997d0
* #define CONSTANT_R3 0x1751997d0LL
*
* [(x128-32 mod P(x) << 32)]' << 1 = 0x0ccaa009e
* #define CONSTANT_R4 0x0ccaa009eLL
*/
.quad 0x00000001751997d0
.quad 0x00000000ccaa009e
/*
* [(x64 mod P(x) << 32)]' << 1 = 0x163cd6124
* #define CONSTANT_R5 0x163cd6124LL
*/
.quad 0x0000000163cd6124
.quad 0x00000000FFFFFFFF
/*
* #define CRCPOLY_TRUE_LE_FULL 0x1DB710641LL
*
* Barrett Reduction constant (u64`) = u` = (x**64 / P(x))`
* = 0x1F7011641LL
* #define CONSTANT_RU 0x1F7011641LL
*/
.quad 0x00000001DB710641
.quad 0x00000001F7011641
.Lcrc32c_constants:
.quad 0x00000000740eef02
.quad 0x000000009e4addf8
.quad 0x00000000f20c0dfe
.quad 0x000000014cd00bd6
.quad 0x00000000dd45aab8
.quad 0x00000000FFFFFFFF
.quad 0x0000000105ec76f0
.quad 0x00000000dea713f1
dCONSTANTl .req d0
dCONSTANTh .req d1
qCONSTANT .req q0
BUF .req r0
LEN .req r1
CRC .req r2
qzr .req q9
/**
* Calculate crc32
* BUF - buffer
* LEN - sizeof buffer (multiple of 16 bytes), LEN should be > 63
* CRC - initial crc32
* return %eax crc32
* uint crc32_pmull_le(unsigned char const *buffer,
* size_t len, uint crc32)
*/
SYM_FUNC_START(crc32_pmull_le)
adr r3, .Lcrc32_constants
b 0f
SYM_FUNC_END(crc32_pmull_le)
SYM_FUNC_START(crc32c_pmull_le)
adr r3, .Lcrc32c_constants
0: bic LEN, LEN, #15
vld1.8 {q1-q2}, [BUF, :128]!
vld1.8 {q3-q4}, [BUF, :128]!
vmov.i8 qzr, #0
vmov.i8 qCONSTANT, #0
vmov.32 dCONSTANTl[0], CRC
veor.8 d2, d2, dCONSTANTl
sub LEN, LEN, #0x40
cmp LEN, #0x40
blt less_64
vld1.64 {qCONSTANT}, [r3]
loop_64: /* 64 bytes Full cache line folding */
sub LEN, LEN, #0x40
vmull.p64 q5, d3, dCONSTANTh
vmull.p64 q6, d5, dCONSTANTh
vmull.p64 q7, d7, dCONSTANTh
vmull.p64 q8, d9, dCONSTANTh
vmull.p64 q1, d2, dCONSTANTl
vmull.p64 q2, d4, dCONSTANTl
vmull.p64 q3, d6, dCONSTANTl
vmull.p64 q4, d8, dCONSTANTl
veor.8 q1, q1, q5
vld1.8 {q5}, [BUF, :128]!
veor.8 q2, q2, q6
vld1.8 {q6}, [BUF, :128]!
veor.8 q3, q3, q7
vld1.8 {q7}, [BUF, :128]!
veor.8 q4, q4, q8
vld1.8 {q8}, [BUF, :128]!
veor.8 q1, q1, q5
veor.8 q2, q2, q6
veor.8 q3, q3, q7
veor.8 q4, q4, q8
cmp LEN, #0x40
bge loop_64
less_64: /* Folding cache line into 128bit */
vldr dCONSTANTl, [r3, #16]
vldr dCONSTANTh, [r3, #24]
vmull.p64 q5, d3, dCONSTANTh
vmull.p64 q1, d2, dCONSTANTl
veor.8 q1, q1, q5
veor.8 q1, q1, q2
vmull.p64 q5, d3, dCONSTANTh
vmull.p64 q1, d2, dCONSTANTl
veor.8 q1, q1, q5
veor.8 q1, q1, q3
vmull.p64 q5, d3, dCONSTANTh
vmull.p64 q1, d2, dCONSTANTl
veor.8 q1, q1, q5
veor.8 q1, q1, q4
teq LEN, #0
beq fold_64
loop_16: /* Folding rest buffer into 128bit */
subs LEN, LEN, #0x10
vld1.8 {q2}, [BUF, :128]!
vmull.p64 q5, d3, dCONSTANTh
vmull.p64 q1, d2, dCONSTANTl
veor.8 q1, q1, q5
veor.8 q1, q1, q2
bne loop_16
fold_64:
/* perform the last 64 bit fold, also adds 32 zeroes
* to the input stream */
vmull.p64 q2, d2, dCONSTANTh
vext.8 q1, q1, qzr, #8
veor.8 q1, q1, q2
/* final 32-bit fold */
vldr dCONSTANTl, [r3, #32]
vldr d6, [r3, #40]
vmov.i8 d7, #0
vext.8 q2, q1, qzr, #4
vand.8 d2, d2, d6
vmull.p64 q1, d2, dCONSTANTl
veor.8 q1, q1, q2
/* Finish up with the bit-reversed barrett reduction 64 ==> 32 bits */
vldr dCONSTANTl, [r3, #48]
vldr dCONSTANTh, [r3, #56]
vand.8 q2, q1, q3
vext.8 q2, qzr, q2, #8
vmull.p64 q2, d5, dCONSTANTh
vand.8 q2, q2, q3
vmull.p64 q2, d4, dCONSTANTl
veor.8 q1, q1, q2
vmov r0, s5
bx lr
SYM_FUNC_END(crc32c_pmull_le)
.macro __crc32, c
subs ip, r2, #8
bmi .Ltail\c
tst r1, #3
bne .Lunaligned\c
teq ip, #0
.Laligned8\c:
ldrd r2, r3, [r1], #8
ARM_BE8(rev r2, r2 )
ARM_BE8(rev r3, r3 )
crc32\c\()w r0, r0, r2
crc32\c\()w r0, r0, r3
bxeq lr
subs ip, ip, #8
bpl .Laligned8\c
.Ltail\c:
tst ip, #4
beq 2f
ldr r3, [r1], #4
ARM_BE8(rev r3, r3 )
crc32\c\()w r0, r0, r3
2: tst ip, #2
beq 1f
ldrh r3, [r1], #2
ARM_BE8(rev16 r3, r3 )
crc32\c\()h r0, r0, r3
1: tst ip, #1
bxeq lr
ldrb r3, [r1]
crc32\c\()b r0, r0, r3
bx lr
.Lunaligned\c:
tst r1, #1
beq 2f
ldrb r3, [r1], #1
subs r2, r2, #1
crc32\c\()b r0, r0, r3
tst r1, #2
beq 0f
2: ldrh r3, [r1], #2
subs r2, r2, #2
ARM_BE8(rev16 r3, r3 )
crc32\c\()h r0, r0, r3
0: subs ip, r2, #8
bpl .Laligned8\c
b .Ltail\c
.endm
.align 5
SYM_TYPED_FUNC_START(crc32_armv8_le)
__crc32
SYM_FUNC_END(crc32_armv8_le)
.align 5
SYM_TYPED_FUNC_START(crc32c_armv8_le)
__crc32 c
SYM_FUNC_END(crc32c_armv8_le)
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