path: root/lib/raid6/rvv.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * RAID-6 syndrome calculation using RISC-V vector instructions
 *
 * Copyright 2024 Institute of Software, CAS.
 * Author: Chunyan Zhang <zhangchunyan@iscas.ac.cn>
 *
 * Based on neon.uc:
 *	Copyright 2002-2004 H. Peter Anvin
 */

#include "rvv.h"

#ifdef __riscv_vector
#error "This code must be built without compiler support for vector"
#endif

static void raid6_rvv1_gen_syndrome_real(int disks, unsigned long bytes, void **ptrs)
{
	u8 **dptr = (u8 **)ptrs;
	u8 *p, *q;
	unsigned long vl, d, nsize;
	int z, z0;

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

	asm volatile (".option	push\n"
		      ".option	arch,+v\n"
		      "vsetvli	%0, x0, e8, m1, ta, ma\n"
		      ".option	pop\n"
		      : "=&r" (vl)
	);

	nsize = vl;

	 /* v0:wp0, v1:wq0, v2:wd0/w20, v3:w10 */
	for (d = 0; d < bytes; d += nsize * 1) {
		/* wq$$ = wp$$ = *(unative_t *)&dptr[z0][d+$$*NSIZE]; */
		asm volatile (".option	push\n"
			      ".option	arch,+v\n"
			      "vle8.v	v0, (%[wp0])\n"
			      "vmv.v.v	v1, v0\n"
			      ".option	pop\n"
			      : :
			      [wp0]"r"(&dptr[z0][d + 0 * nsize])
		);

		for (z = z0 - 1 ; z >= 0 ; z--) {
			/*
			 * w2$$ = MASK(wq$$);
			 * w1$$ = SHLBYTE(wq$$);
			 * w2$$ &= NBYTES(0x1d);
			 * w1$$ ^= w2$$;
			 * wd$$ = *(unative_t *)&dptr[z][d+$$*NSIZE];
			 * wq$$ = w1$$ ^ wd$$;
			 * wp$$ ^= wd$$;
			 */
			asm volatile (".option	push\n"
				      ".option	arch,+v\n"
				      "vsra.vi	v2, v1, 7\n"
				      "vsll.vi	v3, v1, 1\n"
				      "vand.vx	v2, v2, %[x1d]\n"
				      "vxor.vv	v3, v3, v2\n"
				      "vle8.v	v2, (%[wd0])\n"
				      "vxor.vv	v1, v3, v2\n"
				      "vxor.vv	v0, v0, v2\n"
				      ".option	pop\n"
				      : :
				      [wd0]"r"(&dptr[z][d + 0 * nsize]),
				      [x1d]"r"(0x1d)
			);
		}

		/*
		 * *(unative_t *)&p[d+NSIZE*$$] = wp$$;
		 * *(unative_t *)&q[d+NSIZE*$$] = wq$$;
		 */
		asm volatile (".option	push\n"
			      ".option	arch,+v\n"
			      "vse8.v	v0, (%[wp0])\n"
			      "vse8.v	v1, (%[wq0])\n"
			      ".option	pop\n"
			      : :
			      [wp0]"r"(&p[d + nsize * 0]),
			      [wq0]"r"(&q[d + nsize * 0])
		);
	}
}

static void raid6_rvv1_xor_syndrome_real(int disks, int start, int stop,
					 unsigned long bytes, void **ptrs)
{
	u8 **dptr