lib/raid/raid6/loongarch/recov_loongarch_simd.c

Source file repositories/reference/linux-study-clean/lib/raid/raid6/loongarch/recov_loongarch_simd.c

File Facts

System
Linux kernel
Corpus path
lib/raid/raid6/loongarch/recov_loongarch_simd.c
Extension
.c
Size
16612 bytes
Lines
503
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-only
/*
 * RAID6 recovery algorithms in LoongArch SIMD (LSX & LASX)
 *
 * Copyright (C) 2023 WANG Xuerui <git@xen0n.name>
 *
 * Originally based on recov_avx2.c and recov_ssse3.c:
 *
 * Copyright (C) 2012 Intel Corporation
 * Author: Jim Kukunas <james.t.kukunas@linux.intel.com>
 */

#include <linux/mm.h>
#include <linux/raid/pq.h>
#include <asm/cpu-features.h>
#include <asm/fpu.h>
#include "algos.h"

/*
 * Unlike with the syndrome calculation algorithms, there's no boot-time
 * selection of recovery algorithms by benchmarking, so we have to specify
 * the priorities and hope the future cores will all have decent vector
 * support (i.e. no LASX slower than LSX, or even scalar code).
 */

#ifdef CONFIG_CPU_HAS_LSX
static void raid6_2data_recov_lsx(int disks, size_t bytes, int faila,
				  int failb, void **ptrs)
{
	u8 *p, *q, *dp, *dq;
	const u8 *pbmul;	/* P multiplier table for B data */
	const u8 *qmul;		/* Q multiplier table (for both) */

	p = (u8 *)ptrs[disks - 2];
	q = (u8 *)ptrs[disks - 1];

	/*
	 * Compute syndrome with zero for the missing data pages
	 * Use the dead data pages as temporary storage for
	 * delta p and delta q
	 */
	dp = (u8 *)ptrs[faila];
	ptrs[faila] = page_address(ZERO_PAGE(0));
	ptrs[disks - 2] = dp;
	dq = (u8 *)ptrs[failb];
	ptrs[failb] = page_address(ZERO_PAGE(0));
	ptrs[disks - 1] = dq;

	raid6_gen_syndrome(disks, bytes, ptrs);

	/* Restore pointer table */
	ptrs[faila] = dp;
	ptrs[failb] = dq;
	ptrs[disks - 2] = p;
	ptrs[disks - 1] = q;

	/* Now, pick the proper data tables */
	pbmul = raid6_vgfmul[raid6_gfexi[failb - faila]];
	qmul  = raid6_vgfmul[raid6_gfinv[raid6_gfexp[faila] ^ raid6_gfexp[failb]]];

	kernel_fpu_begin();

	/*
	 * vr20, vr21: qmul
	 * vr22, vr23: pbmul
	 */
	asm volatile("vld $vr20, %0" : : "m" (qmul[0]));
	asm volatile("vld $vr21, %0" : : "m" (qmul[16]));
	asm volatile("vld $vr22, %0" : : "m" (pbmul[0]));
	asm volatile("vld $vr23, %0" : : "m" (pbmul[16]));

	while (bytes) {
		/* vr4 - vr7: Q */
		asm volatile("vld $vr4, %0" : : "m" (q[0]));
		asm volatile("vld $vr5, %0" : : "m" (q[16]));
		asm volatile("vld $vr6, %0" : : "m" (q[32]));
		asm volatile("vld $vr7, %0" : : "m" (q[48]));
		/*  vr4 - vr7: Q + Qxy */
		asm volatile("vld $vr8, %0" : : "m" (dq[0]));
		asm volatile("vld $vr9, %0" : : "m" (dq[16]));
		asm volatile("vld $vr10, %0" : : "m" (dq[32]));
		asm volatile("vld $vr11, %0" : : "m" (dq[48]));
		asm volatile("vxor.v $vr4, $vr4, $vr8");
		asm volatile("vxor.v $vr5, $vr5, $vr9");
		asm volatile("vxor.v $vr6, $vr6, $vr10");
		asm volatile("vxor.v $vr7, $vr7, $vr11");
		/* vr0 - vr3: P */
		asm volatile("vld $vr0, %0" : : "m" (p[0]));
		asm volatile("vld $vr1, %0" : : "m" (p[16]));
		asm volatile("vld $vr2, %0" : : "m" (p[32]));

Annotation

Implementation Notes