/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Accelerated GHASH implementation with Intel PCLMULQDQ-NI
 * instructions. This file contains accelerated part of ghash
 * implementation. More information about PCLMULQDQ can be found at:
 *
 * https://www.intel.com/content/dam/develop/external/us/en/documents/clmul-wp-rev-2-02-2014-04-20.pdf
 *
 * Copyright (c) 2009 Intel Corp.
 *   Author: Huang Ying <ying.huang@intel.com>
 *           Vinodh Gopal
 *           Erdinc Ozturk
 *           Deniz Karakoyunlu
 */

#include <linux/linkage.h>
#include <asm/frame.h>

.section        .rodata.cst16.bswap_mask, "aM", @progbits, 16
.align 16
.Lbswap_mask:
        .octa 0x000102030405060708090a0b0c0d0e0f

#define DATA    %xmm0
#define SHASH   %xmm1
#define T1      %xmm2
#define T2      %xmm3
#define T3      %xmm4
#define BSWAP   %xmm5
#define IN1     %xmm6

.text

/*
 * __clmul_gf128mul_ble:        internal ABI
 * input:
 *      DATA:                   operand1
 *      SHASH:                  operand2, hash_key << 1 mod poly
 * output:
 *      DATA:                   operand1 * operand2 mod poly
 * changed:
 *      T1
 *      T2
 *      T3
 */
SYM_FUNC_START_LOCAL(__clmul_gf128mul_ble)
        movaps DATA, T1
        pshufd $0b01001110, DATA, T2
        pshufd $0b01001110, SHASH, T3
        pxor DATA, T2
        pxor SHASH, T3

        pclmulqdq $0x00, SHASH, DATA    # DATA = a0 * b0
        pclmulqdq $0x11, SHASH, T1      # T1 = a1 * b1
        pclmulqdq $0x00, T3, T2         # T2 = (a1 + a0) * (b1 + b0)
        pxor DATA, T2
        pxor T1, T2                     # T2 = a0 * b1 + a1 * b0

        movaps T2, T3
        pslldq $8, T3
        psrldq $8, T2
        pxor T3, DATA
        pxor T2, T1                     # <T1:DATA> is result of
                                        # carry-less multiplication

        # first phase of the reduction
        movaps DATA, T3
        psllq $1, T3
        pxor DATA, T3
        psllq $5, T3
        pxor DATA, T3
        psllq $57, T3
        movaps T3, T2
        pslldq $8, T2
        psrldq $8, T3
        pxor T2, DATA
        pxor T3, T1

        # second phase of the reduction
        movaps DATA, T2
        psrlq $5, T2
        pxor DATA, T2
        psrlq $1, T2
        pxor DATA, T2
        psrlq $1, T2
        pxor T2, T1
        pxor T1, DATA
        RET
SYM_FUNC_END(__clmul_gf128mul_ble)

/* void clmul_ghash_mul(char *dst, const le128 *shash) */
SYM_FUNC_START(clmul_ghash_mul)
        FRAME_BEGIN
        movups (%rdi), DATA
        movups (%rsi), SHASH
        movaps .Lbswap_mask(%rip), BSWAP
        pshufb BSWAP, DATA
        call __clmul_gf128mul_ble
        pshufb BSWAP, DATA
        movups DATA, (%rdi)
        FRAME_END
        RET
SYM_FUNC_END(clmul_ghash_mul)

/*
 * int clmul_ghash_update(char *dst, const char *src, unsigned int srclen,
 *                        const le128 *shash);
 */
SYM_FUNC_START(clmul_ghash_update)
        FRAME_BEGIN
        cmp $16, %rdx
        jb .Lupdate_just_ret    # check length
        movaps .Lbswap_mask(%rip), BSWAP
        movups (%rdi), DATA
        movups (%rcx), SHASH
        pshufb BSWAP, DATA
.align 4
.Lupdate_loop:
        movups (%rsi), IN1
        pshufb BSWAP, IN1
        pxor IN1, DATA
        call __clmul_gf128mul_ble
        sub $16, %rdx
        add $16, %rsi
        cmp $16, %rdx
        jge .Lupdate_loop
        pshufb BSWAP, DATA
        movups DATA, (%rdi)
.Lupdate_just_ret:
        mov %rdx, %rax
        FRAME_END
        RET
SYM_FUNC_END(clmul_ghash_update)