lib/raid/raid6/x86/avx2.c

Source file repositories/reference/linux-study-clean/lib/raid/raid6/x86/avx2.c

File Facts

System
Linux kernel
Corpus path
lib/raid/raid6/x86/avx2.c
Extension
.c
Size
16893 bytes
Lines
456
Domain
Kernel Services
Bucket
lib
Inferred role
Kernel Services: implementation source
Status
source implementation candidate

Why This File Exists

Shared kernel service surface used by multiple subsystems, including helpers, cryptography, virtualization support, and async I/O infrastructure.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2012 Intel Corporation
 * Author: Yuanhan Liu <yuanhan.liu@linux.intel.com>
 *
 * Based on sse2.c: Copyright 2002 H. Peter Anvin - All Rights Reserved
 *
 * AVX2 implementation of RAID-6 syndrome functions
 */

#include <asm/cpufeature.h>
#include <asm/fpu/api.h>
#include "algos.h"

static const struct raid6_avx2_constants {
	u64 x1d[4];
} raid6_avx2_constants __aligned(32) = {
	{ 0x1d1d1d1d1d1d1d1dULL, 0x1d1d1d1d1d1d1d1dULL,
	  0x1d1d1d1d1d1d1d1dULL, 0x1d1d1d1d1d1d1d1dULL,},
};

/*
 * Plain AVX2 implementation
 */
static void raid6_avx21_gen_syndrome(int disks, size_t bytes, void **ptrs)
{
	u8 **dptr = (u8 **)ptrs;
	u8 *p, *q;
	int d, z, z0;

	z0 = disks - 3;		/* Highest data disk */
	p = dptr[z0+1];		/* XOR parity */
	q = dptr[z0+2];		/* RS syndrome */

	kernel_fpu_begin();

	asm volatile("vmovdqa %0,%%ymm0" : : "m" (raid6_avx2_constants.x1d[0]));
	asm volatile("vpxor %ymm3,%ymm3,%ymm3");	/* Zero temp */

	for (d = 0; d < bytes; d += 32) {
		asm volatile("prefetchnta %0" : : "m" (dptr[z0][d]));
		asm volatile("vmovdqa %0,%%ymm2" : : "m" (dptr[z0][d]));/* P[0] */
		asm volatile("prefetchnta %0" : : "m" (dptr[z0-1][d]));
		asm volatile("vmovdqa %ymm2,%ymm4");/* Q[0] */
		asm volatile("vmovdqa %0,%%ymm6" : : "m" (dptr[z0-1][d]));
		for (z = z0-2; z >= 0; z--) {
			asm volatile("prefetchnta %0" : : "m" (dptr[z][d]));
			asm volatile("vpcmpgtb %ymm4,%ymm3,%ymm5");
			asm volatile("vpaddb %ymm4,%ymm4,%ymm4");
			asm volatile("vpand %ymm0,%ymm5,%ymm5");
			asm volatile("vpxor %ymm5,%ymm4,%ymm4");
			asm volatile("vpxor %ymm6,%ymm2,%ymm2");
			asm volatile("vpxor %ymm6,%ymm4,%ymm4");
			asm volatile("vmovdqa %0,%%ymm6" : : "m" (dptr[z][d]));
		}
		asm volatile("vpcmpgtb %ymm4,%ymm3,%ymm5");
		asm volatile("vpaddb %ymm4,%ymm4,%ymm4");
		asm volatile("vpand %ymm0,%ymm5,%ymm5");
		asm volatile("vpxor %ymm5,%ymm4,%ymm4");
		asm volatile("vpxor %ymm6,%ymm2,%ymm2");
		asm volatile("vpxor %ymm6,%ymm4,%ymm4");

		asm volatile("vmovntdq %%ymm2,%0" : "=m" (p[d]));
		asm volatile("vpxor %ymm2,%ymm2,%ymm2");
		asm volatile("vmovntdq %%ymm4,%0" : "=m" (q[d]));
		asm volatile("vpxor %ymm4,%ymm4,%ymm4");
	}

	asm volatile("sfence" : : : "memory");
	kernel_fpu_end();
}

static void raid6_avx21_xor_syndrome(int disks, int start, int stop,
				     size_t bytes, void **ptrs)
{
	u8 **dptr = (u8 **)ptrs;
	u8 *p, *q;
	int d, z, z0;

	z0 = stop;		/* P/Q right side optimization */
	p = dptr[disks-2];	/* XOR parity */
	q = dptr[disks-1];	/* RS syndrome */

	kernel_fpu_begin();

	asm volatile("vmovdqa %0,%%ymm0" : : "m" (raid6_avx2_constants.x1d[0]));

	for (d = 0 ; d < bytes ; d += 32) {
		asm volatile("vmovdqa %0,%%ymm4" :: "m" (dptr[z0][d]));
		asm volatile("vmovdqa %0,%%ymm2" : : "m" (p[d]));

Annotation

Implementation Notes