lib/raid/raid6/x86/recov_avx2.c

Source file repositories/reference/linux-study-clean/lib/raid/raid6/x86/recov_avx2.c

File Facts

System
Linux kernel
Corpus path
lib/raid/raid6/x86/recov_avx2.c
Extension
.c
Size
8846 bytes
Lines
308
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
/*
 * 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/fpu/api.h>
#include "algos.h"

static void raid6_2data_recov_avx2(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) */
	const u8 x0f = 0x0f;

	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();

	/* ymm0 = x0f[16] */
	asm volatile("vpbroadcastb %0, %%ymm7" : : "m" (x0f));

	while (bytes) {
#ifdef CONFIG_X86_64
		asm volatile("vmovdqa %0, %%ymm1" : : "m" (q[0]));
		asm volatile("vmovdqa %0, %%ymm9" : : "m" (q[32]));
		asm volatile("vmovdqa %0, %%ymm0" : : "m" (p[0]));
		asm volatile("vmovdqa %0, %%ymm8" : : "m" (p[32]));
		asm volatile("vpxor %0, %%ymm1, %%ymm1" : : "m" (dq[0]));
		asm volatile("vpxor %0, %%ymm9, %%ymm9" : : "m" (dq[32]));
		asm volatile("vpxor %0, %%ymm0, %%ymm0" : : "m" (dp[0]));
		asm volatile("vpxor %0, %%ymm8, %%ymm8" : : "m" (dp[32]));

		/*
		 * 1 = dq[0]  ^ q[0]
		 * 9 = dq[32] ^ q[32]
		 * 0 = dp[0]  ^ p[0]
		 * 8 = dp[32] ^ p[32]
		 */

		asm volatile("vbroadcasti128 %0, %%ymm4" : : "m" (qmul[0]));
		asm volatile("vbroadcasti128 %0, %%ymm5" : : "m" (qmul[16]));

		asm volatile("vpsraw $4, %ymm1, %ymm3");
		asm volatile("vpsraw $4, %ymm9, %ymm12");
		asm volatile("vpand %ymm7, %ymm1, %ymm1");
		asm volatile("vpand %ymm7, %ymm9, %ymm9");
		asm volatile("vpand %ymm7, %ymm3, %ymm3");
		asm volatile("vpand %ymm7, %ymm12, %ymm12");
		asm volatile("vpshufb %ymm9, %ymm4, %ymm14");
		asm volatile("vpshufb %ymm1, %ymm4, %ymm4");
		asm volatile("vpshufb %ymm12, %ymm5, %ymm15");
		asm volatile("vpshufb %ymm3, %ymm5, %ymm5");
		asm volatile("vpxor %ymm14, %ymm15, %ymm15");
		asm volatile("vpxor %ymm4, %ymm5, %ymm5");

		/*
		 * 5 = qx[0]
		 * 15 = qx[32]
		 */

		asm volatile("vbroadcasti128 %0, %%ymm4" : : "m" (pbmul[0]));

Annotation

Implementation Notes