linux/lib/raid6/recov_neon_inner.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012 Intel Corporation
 * Copyright (C) 2017 Linaro Ltd. <ard.biesheuvel@linaro.org>
 */

#include <arm_neon.h>

#ifdef CONFIG_ARM
/*
 * AArch32 does not provide this intrinsic natively because it does not
 * implement the underlying instruction. AArch32 only provides a 64-bit
 * wide vtbl.8 instruction, so use that instead.
 */
static uint8x16_t vqtbl1q_u8(uint8x16_t a, uint8x16_t b)
{
	union {
		uint8x16_t	val;
		uint8x8x2_t	pair;
	} __a = { a };

	return vcombine_u8(vtbl2_u8(__a.pair, vget_low_u8(b)),
			   vtbl2_u8(__a.pair, vget_high_u8(b)));
}
#endif

void __raid6_2data_recov_neon(int bytes, uint8_t *p, uint8_t *q, uint8_t *dp,
			      uint8_t *dq, const uint8_t *pbmul,
			      const uint8_t *qmul)
{
	uint8x16_t pm0 = vld1q_u8(pbmul);
	uint8x16_t pm1 = vld1q_u8(pbmul + 16);
	uint8x16_t qm0 = vld1q_u8(qmul);
	uint8x16_t qm1 = vld1q_u8(qmul + 16);
	uint8x16_t x0f = vdupq_n_u8(0x0f);

	/*
	 * while ( bytes-- ) {
	 *	uint8_t px, qx, db;
	 *
	 *	px    = *p ^ *dp;
	 *	qx    = qmul[*q ^ *dq];
	 *	*dq++ = db = pbmul[px] ^ qx;
	 *	*dp++ = db ^ px;
	 *	p++; q++;
	 * }
	 */

	while (bytes) {
		uint8x16_t vx, vy, px, qx, db;

		px = veorq_u8(vld1q_u8(p), vld1q_u8(dp));
		vx = veorq_u8(vld1q_u8(q), vld1q_u8(dq));

		vy = vshrq_n_u8(vx, 4);
		vx = vqtbl1q_u8(qm0, vandq_u8(vx, x0f));
		vy = vqtbl1q_u8(qm1, vy);
		qx = veorq_u8(vx, vy);

		vy = vshrq_n_u8(px, 4);
		vx = vqtbl1q_u8(pm0, vandq_u8(px, x0f));
		vy = vqtbl1q_u8(pm1, vy);
		vx = veorq_u8(vx, vy);
		db = veorq_u8(vx, qx);

		vst1q_u8(dq, db);
		vst1q_u8(dp, veorq_u8(db, px));

		bytes -= 16;
		p += 16;
		q += 16;
		dp += 16;
		dq += 16;
	}
}

void __raid6_datap_recov_neon(int bytes, uint8_t *p, uint8_t *q, uint8_t *dq,
			      const uint8_t *qmul)
{
	uint8x16_t qm0 = vld1q_u8(qmul);
	uint8x16_t qm1 = vld1q_u8(qmul + 16);
	uint8x16_t x0f = vdupq_n_u8(0x0f);

	/*
	 * while (bytes--) {
	 *	*p++ ^= *dq = qmul[*q ^ *dq];
	 *	q++; dq++;
	 * }
	 */

	while (bytes) {
		uint8x16_t vx, vy;

		vx = veorq_u8(vld1q_u8(q), vld1q_u8(dq));

		vy = vshrq_n_u8(vx, 4);
		vx = vqtbl1q_u8(qm0, vandq_u8(vx, x0f));
		vy = vqtbl1q_u8(qm1, vy);
		vx = veorq_u8(vx, vy);
		vy = veorq_u8(vx, vld1q_u8(p));

		vst1q_u8(dq, vx);
		vst1q_u8(p, vy);

		bytes -= 16;
		p += 16;
		q += 16;
		dq += 16;
	}
}