root/arch/x86/include/asm/xor_avx.h
/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef _ASM_X86_XOR_AVX_H
#define _ASM_X86_XOR_AVX_H

/*
 * Optimized RAID-5 checksumming functions for AVX
 *
 * Copyright (C) 2012 Intel Corporation
 * Author: Jim Kukunas <james.t.kukunas@linux.intel.com>
 *
 * Based on Ingo Molnar and Zach Brown's respective MMX and SSE routines
 */

#include <linux/compiler.h>
#include <asm/fpu/api.h>

#define BLOCK4(i) \
                BLOCK(32 * i, 0) \
                BLOCK(32 * (i + 1), 1) \
                BLOCK(32 * (i + 2), 2) \
                BLOCK(32 * (i + 3), 3)

#define BLOCK16() \
                BLOCK4(0) \
                BLOCK4(4) \
                BLOCK4(8) \
                BLOCK4(12)

static void xor_avx_2(unsigned long bytes, unsigned long * __restrict p0,
                      const unsigned long * __restrict p1)
{
        unsigned long lines = bytes >> 9;

        kernel_fpu_begin();

        while (lines--) {
#undef BLOCK
#define BLOCK(i, reg) \
do { \
        asm volatile("vmovdqa %0, %%ymm" #reg : : "m" (p1[i / sizeof(*p1)])); \
        asm volatile("vxorps %0, %%ymm" #reg ", %%ymm"  #reg : : \
                "m" (p0[i / sizeof(*p0)])); \
        asm volatile("vmovdqa %%ymm" #reg ", %0" : \
                "=m" (p0[i / sizeof(*p0)])); \
} while (0);

                BLOCK16()

                p0 = (unsigned long *)((uintptr_t)p0 + 512);
                p1 = (unsigned long *)((uintptr_t)p1 + 512);
        }

        kernel_fpu_end();
}

static void xor_avx_3(unsigned long bytes, unsigned long * __restrict p0,
                      const unsigned long * __restrict p1,
                      const unsigned long * __restrict p2)
{
        unsigned long lines = bytes >> 9;

        kernel_fpu_begin();

        while (lines--) {
#undef BLOCK
#define BLOCK(i, reg) \
do { \
        asm volatile("vmovdqa %0, %%ymm" #reg : : "m" (p2[i / sizeof(*p2)])); \
        asm volatile("vxorps %0, %%ymm" #reg ", %%ymm" #reg : : \
                "m" (p1[i / sizeof(*p1)])); \
        asm volatile("vxorps %0, %%ymm" #reg ", %%ymm" #reg : : \
                "m" (p0[i / sizeof(*p0)])); \
        asm volatile("vmovdqa %%ymm" #reg ", %0" : \
                "=m" (p0[i / sizeof(*p0)])); \
} while (0);

                BLOCK16()

                p0 = (unsigned long *)((uintptr_t)p0 + 512);
                p1 = (unsigned long *)((uintptr_t)p1 + 512);
                p2 = (unsigned long *)((uintptr_t)p2 + 512);
        }

        kernel_fpu_end();
}

static void xor_avx_4(unsigned long bytes, unsigned long * __restrict p0,
                      const unsigned long * __restrict p1,
                      const unsigned long * __restrict p2,
                      const unsigned long * __restrict p3)
{
        unsigned long lines = bytes >> 9;

        kernel_fpu_begin();

        while (lines--) {
#undef BLOCK
#define BLOCK(i, reg) \
do { \
        asm volatile("vmovdqa %0, %%ymm" #reg : : "m" (p3[i / sizeof(*p3)])); \
        asm volatile("vxorps %0, %%ymm" #reg ", %%ymm" #reg : : \
                "m" (p2[i / sizeof(*p2)])); \
        asm volatile("vxorps %0, %%ymm" #reg ", %%ymm" #reg : : \
                "m" (p1[i / sizeof(*p1)])); \
        asm volatile("vxorps %0, %%ymm" #reg ", %%ymm" #reg : : \
                "m" (p0[i / sizeof(*p0)])); \
        asm volatile("vmovdqa %%ymm" #reg ", %0" : \
                "=m" (p0[i / sizeof(*p0)])); \
} while (0);

                BLOCK16();

                p0 = (unsigned long *)((uintptr_t)p0 + 512);
                p1 = (unsigned long *)((uintptr_t)p1 + 512);
                p2 = (unsigned long *)((uintptr_t)p2 + 512);
                p3 = (unsigned long *)((uintptr_t)p3 + 512);
        }

        kernel_fpu_end();
}

static void xor_avx_5(unsigned long bytes, unsigned long * __restrict p0,
             const unsigned long * __restrict p1,
             const unsigned long * __restrict p2,
             const unsigned long * __restrict p3,
             const unsigned long * __restrict p4)
{
        unsigned long lines = bytes >> 9;

        kernel_fpu_begin();

        while (lines--) {
#undef BLOCK
#define BLOCK(i, reg) \
do { \
        asm volatile("vmovdqa %0, %%ymm" #reg : : "m" (p4[i / sizeof(*p4)])); \
        asm volatile("vxorps %0, %%ymm" #reg ", %%ymm" #reg : : \
                "m" (p3[i / sizeof(*p3)])); \
        asm volatile("vxorps %0, %%ymm" #reg ", %%ymm" #reg : : \
                "m" (p2[i / sizeof(*p2)])); \
        asm volatile("vxorps %0, %%ymm" #reg ", %%ymm" #reg : : \
                "m" (p1[i / sizeof(*p1)])); \
        asm volatile("vxorps %0, %%ymm" #reg ", %%ymm" #reg : : \
                "m" (p0[i / sizeof(*p0)])); \
        asm volatile("vmovdqa %%ymm" #reg ", %0" : \
                "=m" (p0[i / sizeof(*p0)])); \
} while (0);

                BLOCK16()

                p0 = (unsigned long *)((uintptr_t)p0 + 512);
                p1 = (unsigned long *)((uintptr_t)p1 + 512);
                p2 = (unsigned long *)((uintptr_t)p2 + 512);
                p3 = (unsigned long *)((uintptr_t)p3 + 512);
                p4 = (unsigned long *)((uintptr_t)p4 + 512);
        }

        kernel_fpu_end();
}

static struct xor_block_template xor_block_avx = {
        .name = "avx",
        .do_2 = xor_avx_2,
        .do_3 = xor_avx_3,
        .do_4 = xor_avx_4,
        .do_5 = xor_avx_5,
};

#define AVX_XOR_SPEED \
do { \
        if (boot_cpu_has(X86_FEATURE_AVX) && boot_cpu_has(X86_FEATURE_OSXSAVE)) \
                xor_speed(&xor_block_avx); \
} while (0)

#define AVX_SELECT(FASTEST) \
        (boot_cpu_has(X86_FEATURE_AVX) && boot_cpu_has(X86_FEATURE_OSXSAVE) ? &xor_block_avx : FASTEST)

#endif