raid6: Add LoongArch SIMD recovery implementation

Similar to the syndrome calculation, the recovery algorithms also work
on 64 bytes at a time to align with the L1 cache line size of current
and future LoongArch cores (that we care about). Which means
unrolled-by-4 LSX and unrolled-by-2 LASX code.

The assembly is originally based on the x86 SSSE3/AVX2 ports, but
register allocation has been redone to take advantage of LSX/LASX's 32
vector registers, and instruction sequence has been optimized to suit
(e.g. LoongArch can perform per-byte srl and andi on vectors, but x86
cannot).

Performance numbers measured by instrumenting the raid6test code, on a
3A5000 system clocked at 2.5GHz:

> lasx  2data: 354.987 MiB/s
> lasx  datap: 350.430 MiB/s
> lsx   2data: 340.026 MiB/s
> lsx   datap: 337.318 MiB/s
> intx1 2data: 164.280 MiB/s
> intx1 datap: 187.966 MiB/s

Because recovery algorithms are chosen solely based on priority and
availability, lasx is marked as priority 2 and lsx priority 1. At least
for the current generation of LoongArch micro-architectures, LASX should
always be faster than LSX whenever supported, and have similar power
consumption characteristics (because the only known LASX-capable uarch,
the LA464, always compute the full 256-bit result for vector ops).
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

include/linux/raid/pq.h

@@ -125,6 +125,8 @@ extern const struct raid6_recov_calls raid6_recov_avx2;
 extern const struct raid6_recov_calls raid6_recov_avx512;
 extern const struct raid6_recov_calls raid6_recov_s390xc;
 extern const struct raid6_recov_calls raid6_recov_neon;
+extern const struct raid6_recov_calls raid6_recov_lsx;
+extern const struct raid6_recov_calls raid6_recov_lasx;
 
 extern const struct raid6_calls raid6_neonx1;
 extern const struct raid6_calls raid6_neonx2;

lib/raid6/Makefile

@@ -9,7 +9,7 @@ raid6_pq-$(CONFIG_ALTIVEC) += altivec1.o altivec2.o altivec4.o altivec8.o \
                               vpermxor1.o vpermxor2.o vpermxor4.o vpermxor8.o
 raid6_pq-$(CONFIG_KERNEL_MODE_NEON) += neon.o neon1.o neon2.o neon4.o neon8.o recov_neon.o recov_neon_inner.o
 raid6_pq-$(CONFIG_S390) += s390vx8.o recov_s390xc.o
-raid6_pq-$(CONFIG_LOONGARCH) += loongarch_simd.o
+raid6_pq-$(CONFIG_LOONGARCH) += loongarch_simd.o recov_loongarch_simd.o
 
 hostprogs	+= mktables
 

lib/raid6/algos.c

@@ -111,6 +111,14 @@ const struct raid6_recov_calls *const raid6_recov_algos[] = {
 #endif
 #if defined(CONFIG_KERNEL_MODE_NEON)
 	&raid6_recov_neon,
+#endif
+#ifdef CONFIG_LOONGARCH
+#ifdef CONFIG_CPU_HAS_LASX
+	&raid6_recov_lasx,
+#endif
+#ifdef CONFIG_CPU_HAS_LSX
+	&raid6_recov_lsx,
+#endif
 #endif
 	&raid6_recov_intx1,
 	NULL

lib/raid6/recov_loongarch_simd.c

+// 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/raid/pq.h>
+#include "loongarch.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 int raid6_has_lsx(void)
+{
+	return 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] = (void *)raid6_empty_zero_page;
+	ptrs[disks - 2] = dp;
+	dq = (u8 *)ptrs[failb];
+	ptrs[failb] = (void *)raid6_empty_zero_page;
+	ptrs[disks - 1] = dq;
+
+	raid6_call.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]));
+		asm volatile("vld $vr3, %0" : : "m" (p[48]));
+		/* vr0 - vr3: P + Pxy */
+		asm volatile("vld $vr8, %0" : : "m" (dp[0]));
+		asm volatile("vld $vr9, %0" : : "m" (dp[16]));
+		asm volatile("vld $vr10, %0" : : "m" (dp[32]));
+		asm volatile("vld $vr11, %0" : : "m" (dp[48]));
+		asm volatile("vxor.v $vr0, $vr0, $vr8");
+		asm volatile("vxor.v $vr1, $vr1, $vr9");
+		asm volatile("vxor.v $vr2, $vr2, $vr10");
+		asm volatile("vxor.v $vr3, $vr3, $vr11");
+
+		/* vr8 - vr11: higher 4 bits of each byte of (Q + Qxy) */
+		asm volatile("vsrli.b $vr8, $vr4, 4");
+		asm volatile("vsrli.b $vr9, $vr5, 4");
+		asm volatile("vsrli.b $vr10, $vr6, 4");
+		asm volatile("vsrli.b $vr11, $vr7, 4");
+		/* vr4 - vr7: lower 4 bits of each byte of (Q + Qxy) */
+		asm volatile("vandi.b $vr4, $vr4, 0x0f");
+		asm volatile("vandi.b $vr5, $vr5, 0x0f");
+		asm volatile("vandi.b $vr6, $vr6, 0x0f");
+		asm volatile("vandi.b $vr7, $vr7, 0x0f");
+		/* lookup from qmul[0] */
+		asm volatile("vshuf.b $vr4, $vr20, $vr20, $vr4");
+		asm volatile("vshuf.b $vr5, $vr20, $vr20, $vr5");
+		asm volatile("vshuf.b $vr6, $vr20, $vr20, $vr6");
+		asm volatile("vshuf.b $vr7, $vr20, $vr20, $vr7");
+		/* lookup from qmul[16] */
+		asm volatile("vshuf.b $vr8, $vr21, $vr21, $vr8");
+		asm volatile("vshuf.b $vr9, $vr21, $vr21, $vr9");
+		asm volatile("vshuf.b $vr10, $vr21, $vr21, $vr10");
+		asm volatile("vshuf.b $vr11, $vr21, $vr21, $vr11");
+		/* vr16 - vr19: B(Q + Qxy) */
+		asm volatile("vxor.v $vr16, $vr8, $vr4");
+		asm volatile("vxor.v $vr17, $vr9, $vr5");
+		asm volatile("vxor.v $vr18, $vr10, $vr6");
+		asm volatile("vxor.v $vr19, $vr11, $vr7");
+
+		/* vr4 - vr7: higher 4 bits of each byte of (P + Pxy) */
+		asm volatile("vsrli.b $vr4, $vr0, 4");
+		asm volatile("vsrli.b $vr5, $vr1, 4");
+		asm volatile("vsrli.b $vr6, $vr2, 4");
+		asm volatile("vsrli.b $vr7, $vr3, 4");
+		/* vr12 - vr15: lower 4 bits of each byte of (P + Pxy) */
+		asm volatile("vandi.b $vr12, $vr0, 0x0f");
+		asm volatile("vandi.b $vr13, $vr1, 0x0f");
+		asm volatile("vandi.b $vr14, $vr2, 0x0f");
+		asm volatile("vandi.b $vr15, $vr3, 0x0f");
+		/* lookup from pbmul[0] */
+		asm volatile("vshuf.b $vr12, $vr22, $vr22, $vr12");
+		asm volatile("vshuf.b $vr13, $vr22, $vr22, $vr13");
+		asm volatile("vshuf.b $vr14, $vr22, $vr22, $vr14");
+		asm volatile("vshuf.b $vr15, $vr22, $vr22, $vr15");
+		/* lookup from pbmul[16] */
+		asm volatile("vshuf.b $vr4, $vr23, $vr23, $vr4");
+		asm volatile("vshuf.b $vr5, $vr23, $vr23, $vr5");
+		asm volatile("vshuf.b $vr6, $vr23, $vr23, $vr6");
+		asm volatile("vshuf.b $vr7, $vr23, $vr23, $vr7");
+		/* vr4 - vr7: A(P + Pxy) */
+		asm volatile("vxor.v $vr4, $vr4, $vr12");
+		asm volatile("vxor.v $vr5, $vr5, $vr13");
+		asm volatile("vxor.v $vr6, $vr6, $vr14");
+		asm volatile("vxor.v $vr7, $vr7, $vr15");
+
+		/* vr4 - vr7: A(P + Pxy) + B(Q + Qxy) = Dx */
+		asm volatile("vxor.v $vr4, $vr4, $vr16");
+		asm volatile("vxor.v $vr5, $vr5, $vr17");
+		asm volatile("vxor.v $vr6, $vr6, $vr18");
+		asm volatile("vxor.v $vr7, $vr7, $vr19");
+		asm volatile("vst $vr4, %0" : "=m" (dq[0]));
+		asm volatile("vst $vr5, %0" : "=m" (dq[16]));
+		asm volatile("vst $vr6, %0" : "=m" (dq[32]));
+		asm volatile("vst $vr7, %0" : "=m" (dq[48]));
+
+		/* vr0 - vr3: P + Pxy + Dx = Dy */
+		asm volatile("vxor.v $vr0, $vr0, $vr4");
+		asm volatile("vxor.v $vr1, $vr1, $vr5");
+		asm volatile("vxor.v $vr2, $vr2, $vr6");
+		asm volatile("vxor.v $vr3, $vr3, $vr7");
+		asm volatile("vst $vr0, %0" : "=m" (dp[0]));
+		asm volatile("vst $vr1, %0" : "=m" (dp[16]));
+		asm volatile("vst $vr2, %0" : "=m" (dp[32]));
+		asm volatile("vst $vr3, %0" : "=m" (dp[48]));
+
+		bytes -= 64;
+		p += 64;
+		q += 64;
+		dp += 64;
+		dq += 64;
+	}
+
+	kernel_fpu_end();
+}
+
+static void raid6_datap_recov_lsx(int disks, size_t bytes, int faila,
+				  void **ptrs)
+{
+	u8 *p, *q, *dq;
+	const u8 *qmul;		/* Q multiplier table */
+
+	p = (u8 *)ptrs[disks - 2];
+	q = (u8 *)ptrs[disks - 1];
+
+	/*
+	 * Compute syndrome with zero for the missing data page
+	 * Use the dead data page as temporary storage for delta q
+	 */
+	dq = (u8 *)ptrs[faila];
+	ptrs[faila] = (void *)raid6_empty_zero_page;
+	ptrs[disks - 1] = dq;
+
+	raid6_call.gen_syndrome(disks, bytes, ptrs);
+
+	/* Restore pointer table */
+	ptrs[faila] = dq;
+	ptrs[disks - 1] = q;
+
+	/* Now, pick the proper data tables */
+	qmul  = raid6_vgfmul[raid6_gfinv[raid6_gfexp[faila]]];
+
+	kernel_fpu_begin();
+
+	/* vr22, vr23: qmul */
+	asm volatile("vld $vr22, %0" : : "m" (qmul[0]));
+	asm volatile("vld $vr23, %0" : : "m" (qmul[16]));
+
+	while (bytes) {
+		/* vr0 - vr3: P + Dx */
+		asm volatile("vld $vr0, %0" : : "m" (p[0]));
+		asm volatile("vld $vr1, %0" : : "m" (p[16]));
+		asm volatile("vld $vr2, %0" : : "m" (p[32]));
+		asm volatile("vld $vr3, %0" : : "m" (p[48]));
+		/* vr4 - vr7: Qx */
+		asm volatile("vld $vr4, %0" : : "m" (dq[0]));
+		asm volatile("vld $vr5, %0" : : "m" (dq[16]));
+		asm volatile("vld $vr6, %0" : : "m" (dq[32]));
+		asm volatile("vld $vr7, %0" : : "m" (dq[48]));
+		/* vr4 - vr7: Q + Qx */
+		asm volatile("vld $vr8, %0" : : "m" (q[0]));
+		asm volatile("vld $vr9, %0" : : "m" (q[16]));
+		asm volatile("vld $vr10, %0" : : "m" (q[32]));
+		asm volatile("vld $vr11, %0" : : "m" (q[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");
+
+		/* vr8 - vr11: higher 4 bits of each byte of (Q + Qx) */
+		asm volatile("vsrli.b $vr8, $vr4, 4");
+		asm volatile("vsrli.b $vr9, $vr5, 4");
+		asm volatile("vsrli.b $vr10, $vr6, 4");
+		asm volatile("vsrli.b $vr11, $vr7, 4");
+		/* vr4 - vr7: lower 4 bits of each byte of (Q + Qx) */
+		asm volatile("vandi.b $vr4, $vr4, 0x0f");
+		asm volatile("vandi.b $vr5, $vr5, 0x0f");
+		asm volatile("vandi.b $vr6, $vr6, 0x0f");
+		asm volatile("vandi.b $vr7, $vr7, 0x0f");
+		/* lookup from qmul[0] */
+		asm volatile("vshuf.b $vr4, $vr22, $vr22, $vr4");
+		asm volatile("vshuf.b $vr5, $vr22, $vr22, $vr5");
+		asm volatile("vshuf.b $vr6, $vr22, $vr22, $vr6");
+		asm volatile("vshuf.b $vr7, $vr22, $vr22, $vr7");
+		/* lookup from qmul[16] */
+		asm volatile("vshuf.b $vr8, $vr23, $vr23, $vr8");
+		asm volatile("vshuf.b $vr9, $vr23, $vr23, $vr9");
+		asm volatile("vshuf.b $vr10, $vr23, $vr23, $vr10");
+		asm volatile("vshuf.b $vr11, $vr23, $vr23, $vr11");
+		/* vr4 - vr7: qmul(Q + Qx) = Dx */
+		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");
+		asm volatile("vst $vr4, %0" : "=m" (dq[0]));
+		asm volatile("vst $vr5, %0" : "=m" (dq[16]));
+		asm volatile("vst $vr6, %0" : "=m" (dq[32]));
+		asm volatile("vst $vr7, %0" : "=m" (dq[48]));
+
+		/* vr0 - vr3: P + Dx + Dx = P */
+		asm volatile("vxor.v $vr0, $vr0, $vr4");
+		asm volatile("vxor.v $vr1, $vr1, $vr5");
+		asm volatile("vxor.v $vr2, $vr2, $vr6");
+		asm volatile("vxor.v $vr3, $vr3, $vr7");
+		asm volatile("vst $vr0, %0" : "=m" (p[0]));
+		asm volatile("vst $vr1, %0" : "=m" (p[16]));
+		asm volatile("vst $vr2, %0" : "=m" (p[32]));
+		asm volatile("vst $vr3, %0" : "=m" (p[48]));
+
+		bytes -= 64;
+		p += 64;
+		q += 64;
+		dq += 64;
+	}
+
+	kernel_fpu_end();
+}
+
+const struct raid6_recov_calls raid6_recov_lsx = {
+	.data2 = raid6_2data_recov_lsx,
+	.datap = raid6_datap_recov_lsx,
+	.valid = raid6_has_lsx,
+	.name = "lsx",
+	.priority = 1,
+};
+#endif /* CONFIG_CPU_HAS_LSX */
+
+#ifdef CONFIG_CPU_HAS_LASX
+static int raid6_has_lasx(void)
+{
+	return cpu_has_lasx;
+}
+
+static void raid6_2data_recov_lasx(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] = (void *)raid6_empty_zero_page;
+	ptrs[disks - 2] = dp;
+	dq = (u8 *)ptrs[failb];
+	ptrs[failb] = (void *)raid6_empty_zero_page;
+	ptrs[disks - 1] = dq;
+
+	raid6_call.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();
+
+	/*
+	 * xr20, xr21: qmul
+	 * xr22, xr23: 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]));
+	asm volatile("xvreplve0.q $xr20, $xr20");
+	asm volatile("xvreplve0.q $xr21, $xr21");
+	asm volatile("xvreplve0.q $xr22, $xr22");
+	asm volatile("xvreplve0.q $xr23, $xr23");
+
+	while (bytes) {
+		/* xr0, xr1: Q */
+		asm volatile("xvld $xr0, %0" : : "m" (q[0]));
+		asm volatile("xvld $xr1, %0" : : "m" (q[32]));
+		/* xr0, xr1: Q + Qxy */
+		asm volatile("xvld $xr4, %0" : : "m" (dq[0]));
+		asm volatile("xvld $xr5, %0" : : "m" (dq[32]));
+		asm volatile("xvxor.v $xr0, $xr0, $xr4");
+		asm volatile("xvxor.v $xr1, $xr1, $xr5");
+		/* xr2, xr3: P */
+		asm volatile("xvld $xr2, %0" : : "m" (p[0]));
+		asm volatile("xvld $xr3, %0" : : "m" (p[32]));
+		/* xr2, xr3: P + Pxy */
+		asm volatile("xvld $xr4, %0" : : "m" (dp[0]));
+		asm volatile("xvld $xr5, %0" : : "m" (dp[32]));
+		asm volatile("xvxor.v $xr2, $xr2, $xr4");
+		asm volatile("xvxor.v $xr3, $xr3, $xr5");
+
+		/* xr4, xr5: higher 4 bits of each byte of (Q + Qxy) */
+		asm volatile("xvsrli.b $xr4, $xr0, 4");
+		asm volatile("xvsrli.b $xr5, $xr1, 4");
+		/* xr0, xr1: lower 4 bits of each byte of (Q + Qxy) */
+		asm volatile("xvandi.b $xr0, $xr0, 0x0f");
+		asm volatile("xvandi.b $xr1, $xr1, 0x0f");
+		/* lookup from qmul[0] */
+		asm volatile("xvshuf.b $xr0, $xr20, $xr20, $xr0");
+		asm volatile("xvshuf.b $xr1, $xr20, $xr20, $xr1");
+		/* lookup from qmul[16] */
+		asm volatile("xvshuf.b $xr4, $xr21, $xr21, $xr4");
+		asm volatile("xvshuf.b $xr5, $xr21, $xr21, $xr5");
+		/* xr6, xr7: B(Q + Qxy) */
+		asm volatile("xvxor.v $xr6, $xr4, $xr0");
+		asm volatile("xvxor.v $xr7, $xr5, $xr1");
+
+		/* xr4, xr5: higher 4 bits of each byte of (P + Pxy) */
+		asm volatile("xvsrli.b $xr4, $xr2, 4");
+		asm volatile("xvsrli.b $xr5, $xr3, 4");
+		/* xr0, xr1: lower 4 bits of each byte of (P + Pxy) */
+		asm volatile("xvandi.b $xr0, $xr2, 0x0f");
+		asm volatile("xvandi.b $xr1, $xr3, 0x0f");
+		/* lookup from pbmul[0] */
+		asm volatile("xvshuf.b $xr0, $xr22, $xr22, $xr0");
+		asm volatile("xvshuf.b $xr1, $xr22, $xr22, $xr1");
+		/* lookup from pbmul[16] */
+		asm volatile("xvshuf.b $xr4, $xr23, $xr23, $xr4");
+		asm volatile("xvshuf.b $xr5, $xr23, $xr23, $xr5");
+		/* xr0, xr1: A(P + Pxy) */
+		asm volatile("xvxor.v $xr0, $xr0, $xr4");
+		asm volatile("xvxor.v $xr1, $xr1, $xr5");
+
+		/* xr0, xr1: A(P + Pxy) + B(Q + Qxy) = Dx */
+		asm volatile("xvxor.v $xr0, $xr0, $xr6");
+		asm volatile("xvxor.v $xr1, $xr1, $xr7");
+
+		/* xr2, xr3: P + Pxy + Dx = Dy */
+		asm volatile("xvxor.v $xr2, $xr2, $xr0");
+		asm volatile("xvxor.v $xr3, $xr3, $xr1");
+
+		asm volatile("xvst $xr0, %0" : "=m" (dq[0]));
+		asm volatile("xvst $xr1, %0" : "=m" (dq[32]));
+		asm volatile("xvst $xr2, %0" : "=m" (dp[0]));
+		asm volatile("xvst $xr3, %0" : "=m" (dp[32]));
+
+		bytes -= 64;
+		p += 64;
+		q += 64;
+		dp += 64;
+		dq += 64;
+	}
+
+	kernel_fpu_end();
+}
+
+static void raid6_datap_recov_lasx(int disks, size_t bytes, int faila,
+				   void **ptrs)
+{
+	u8 *p, *q, *dq;
+	const u8 *qmul;		/* Q multiplier table */
+
+	p = (u8 *)ptrs[disks - 2];
+	q = (u8 *)ptrs[disks - 1];
+
+	/*
+	 * Compute syndrome with zero for the missing data page
+	 * Use the dead data page as temporary storage for delta q
+	 */
+	dq = (u8 *)ptrs[faila];
+	ptrs[faila] = (void *)raid6_empty_zero_page;
+	ptrs[disks - 1] = dq;
+
+	raid6_call.gen_syndrome(disks, bytes, ptrs);
+
+	/* Restore pointer table */
+	ptrs[faila] = dq;
+	ptrs[disks - 1] = q;
+
+	/* Now, pick the proper data tables */
+	qmul  = raid6_vgfmul[raid6_gfinv[raid6_gfexp[faila]]];
+
+	kernel_fpu_begin();
+
+	/* xr22, xr23: qmul */
+	asm volatile("vld $vr22, %0" : : "m" (qmul[0]));
+	asm volatile("xvreplve0.q $xr22, $xr22");
+	asm volatile("vld $vr23, %0" : : "m" (qmul[16]));
+	asm volatile("xvreplve0.q $xr23, $xr23");
+
+	while (bytes) {
+		/* xr0, xr1: P + Dx */
+		asm volatile("xvld $xr0, %0" : : "m" (p[0]));
+		asm volatile("xvld $xr1, %0" : : "m" (p[32]));
+		/* xr2, xr3: Qx */
+		asm volatile("xvld $xr2, %0" : : "m" (dq[0]));
+		asm volatile("xvld $xr3, %0" : : "m" (dq[32]));
+		/* xr2, xr3: Q + Qx */
+		asm volatile("xvld $xr4, %0" : : "m" (q[0]));
+		asm volatile("xvld $xr5, %0" : : "m" (q[32]));
+		asm volatile("xvxor.v $xr2, $xr2, $xr4");
+		asm volatile("xvxor.v $xr3, $xr3, $xr5");
+
+		/* xr4, xr5: higher 4 bits of each byte of (Q + Qx) */
+		asm volatile("xvsrli.b $xr4, $xr2, 4");
+		asm volatile("xvsrli.b $xr5, $xr3, 4");
+		/* xr2, xr3: lower 4 bits of each byte of (Q + Qx) */
+		asm volatile("xvandi.b $xr2, $xr2, 0x0f");
+		asm volatile("xvandi.b $xr3, $xr3, 0x0f");
+		/* lookup from qmul[0] */
+		asm volatile("xvshuf.b $xr2, $xr22, $xr22, $xr2");
+		asm volatile("xvshuf.b $xr3, $xr22, $xr22, $xr3");
+		/* lookup from qmul[16] */
+		asm volatile("xvshuf.b $xr4, $xr23, $xr23, $xr4");
+		asm volatile("xvshuf.b $xr5, $xr23, $xr23, $xr5");
+		/* xr2, xr3: qmul(Q + Qx) = Dx */
+		asm volatile("xvxor.v $xr2, $xr2, $xr4");
+		asm volatile("xvxor.v $xr3, $xr3, $xr5");
+
+		/* xr0, xr1: P + Dx + Dx = P */
+		asm volatile("xvxor.v $xr0, $xr0, $xr2");
+		asm volatile("xvxor.v $xr1, $xr1, $xr3");
+
+		asm volatile("xvst $xr2, %0" : "=m" (dq[0]));
+		asm volatile("xvst $xr3, %0" : "=m" (dq[32]));
+		asm volatile("xvst $xr0, %0" : "=m" (p[0]));
+		asm volatile("xvst $xr1, %0" : "=m" (p[32]));
+
+		bytes -= 64;
+		p += 64;
+		q += 64;
+		dq += 64;
+	}
+
+	kernel_fpu_end();
+}
+
+const struct raid6_recov_calls raid6_recov_lasx = {
+	.data2 = raid6_2data_recov_lasx,
+	.datap = raid6_datap_recov_lasx,
+	.valid = raid6_has_lasx,
+	.name = "lasx",
+	.priority = 2,
+};
+#endif /* CONFIG_CPU_HAS_LASX */

lib/raid6/test/Makefile

@@ -65,7 +65,7 @@ else ifeq ($(HAS_ALTIVEC),yes)
         OBJS += altivec1.o altivec2.o altivec4.o altivec8.o \
                 vpermxor1.o vpermxor2.o vpermxor4.o vpermxor8.o
 else ifeq ($(ARCH),loongarch64)
-        OBJS += loongarch_simd.o
+        OBJS += loongarch_simd.o recov_loongarch_simd.o
 endif
 
 .c.o: