/* SPDX-License-Identifier: GPL-2.0 */
/*
* NH - ε-almost-universal hash function, x86_64 AVX2 accelerated
*
* Copyright 2018 Google LLC
*
* Author: Eric Biggers <ebiggers@google.com>
*/
#include <linux/linkage.h>
#define PASS0_SUMS %ymm0
#define PASS1_SUMS %ymm1
#define PASS2_SUMS %ymm2
#define PASS3_SUMS %ymm3
#define K0 %ymm4
#define K0_XMM %xmm4
#define K1 %ymm5
#define K1_XMM %xmm5
#define K2 %ymm6
#define K2_XMM %xmm6
#define K3 %ymm7
#define K3_XMM %xmm7
#define T0 %ymm8
#define T1 %ymm9
#define T2 %ymm10
#define T2_XMM %xmm10
#define T3 %ymm11
#define T3_XMM %xmm11
#define T4 %ymm12
#define T5 %ymm13
#define T6 %ymm14
#define T7 %ymm15
#define KEY %rdi
#define MESSAGE %rsi
#define MESSAGE_LEN %rdx
#define HASH %rcx
.macro _nh_2xstride k0, k1, k2, k3
// Add message words to key words
vpaddd \k0, T3, T0
vpaddd \k1, T3, T1
vpaddd \k2, T3, T2
vpaddd \k3, T3, T3
// Multiply 32x32 => 64 and accumulate
vpshufd $0x10, T0, T4
vpshufd $0x32, T0, T0
vpshufd $0x10, T1, T5
vpshufd $0x32, T1, T1
vpshufd $0x10, T2, T6
vpshufd $0x32, T2, T2
vpshufd $0x10, T3, T7
vpshufd $0x32, T3, T3
vpmuludq T4, T0, T0
vpmuludq T5, T1, T1
vpmuludq T6, T2, T2
vpmuludq T7, T3, T3
vpaddq T0, PASS0_SUMS, PASS0_SUMS
vpaddq T1, PASS1_SUMS, PASS1_SUMS
vpaddq T2, PASS2_SUMS, PASS2_SUMS
vpaddq T3, PASS3_SUMS, PASS3_SUMS
.endm
/*
* void nh_avx2(const u32 *key, const u8 *message, size_t message_len,
* u8 hash[NH_HASH_BYTES])
*
* It's guaranteed that message_len % 16 == 0.
*/
ENTRY(nh_avx2)
vmovdqu 0x00(KEY), K0
vmovdqu 0x10(KEY), K1
add $0x20, KEY
vpxor PASS0_SUMS, PASS0_SUMS, PASS0_SUMS
vpxor PASS1_SUMS, PASS1_SUMS, PASS1_SUMS
vpxor PASS2_SUMS, PASS2_SUMS, PASS2_SUMS
vpxor PASS3_SUMS, PASS3_SUMS, PASS3_SUMS
sub $0x40, MESSAGE_LEN
jl .Lloop4_done
.Lloop4:
vmovdqu (MESSAGE), T3
vmovdqu 0x00(KEY), K2
vmovdqu 0x10(KEY), K3
_nh_2xstride K0, K1, K2, K3
vmovdqu 0x20(MESSAGE), T3
vmovdqu 0x20(KEY), K0
vmovdqu 0x30(KEY), K1
_nh_2xstride K2, K3, K0, K1
add $0x40, MESSAGE
add $0x40, KEY
sub $0x40, MESSAGE_LEN
jge .Lloop4
.Lloop4_done:
and $0x3f, MESSAGE_LEN
jz .Ldone
cmp $0x20, MESSAGE_LEN
jl .Llast
// 2 or 3 strides remain; do 2 more.
vmovdqu (MESSAGE), T3
vmovdqu 0x00(KEY), K2
vmovdqu 0x10(KEY), K3
_nh_2xstride K0, K1, K2, K3
add $0x20, MESSAGE
add $0x20, KEY
sub $0x20, MESSAGE_LEN
jz .Ldone
vmovdqa K2, K0
vmovdqa K3, K1
.Llast:
// Last stride. Zero the high 128 bits of the message and keys so they
// don't affect the result when processing them like 2 strides.
vmovdqu (MESSAGE), T3_XMM
vmovdqa K0_XMM, K0_XMM
vmovdqa K1_XMM, K1_XMM
vmovdqu 0x00(KEY), K2_XMM
vmovdqu 0x10(KEY), K3_XMM
_nh_2xstride K0, K1, K2, K3
.Ldone:
// Sum the accumulators for each pass, then store the sums to 'hash'
// PASS0_SUMS is (0A 0B 0C 0D)
// PASS1_SUMS is (1A 1B 1C 1D)
// PASS2_SUMS is (2A 2B 2C 2D)
// PASS3_SUMS is (3A 3B 3C 3D)
// We need the horizontal sums:
// (0A + 0B + 0C + 0D,
// 1A + 1B + 1C + 1D,
// 2A + 2B + 2C + 2D,
// 3A + 3B + 3C + 3D)
//
vpunpcklqdq PASS1_SUMS, PASS0_SUMS, T0 // T0 = (0A 1A 0C 1C)
vpunpckhqdq PASS1_SUMS, PASS0_SUMS, T1 // T1 = (0B 1B 0D 1D)
vpunpcklqdq PASS3_SUMS, PASS2_SUMS, T2 // T2 = (2A 3A 2C 3C)
vpunpckhqdq PASS3_SUMS, PASS2_SUMS, T3 // T3 = (2B 3B 2D 3D)
vinserti128 $0x1, T2_XMM, T0, T4 // T4 = (0A 1A 2A 3A)
vinserti128 $0x1, T3_XMM, T1, T5 // T5 = (0B 1B 2B 3B)
vperm2i128 $0x31, T2, T0, T0 // T0 = (0C 1C 2C 3C)
vperm2i128 $0x31, T3, T1, T1 // T1 = (0D 1D 2D 3D)
vpaddq T5, T4, T4
vpaddq T1, T0, T0
vpaddq T4, T0, T0
vmovdqu T0, (HASH)
ret
ENDPROC(nh_avx2)