/*
* Copyright (c) 2018, Intel Corporation.
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/

#include "precompiled.hpp"
#include "asm/assembler.hpp"
#include "asm/assembler.inline.hpp"
#include "runtime/stubRoutines.hpp"
#include "macroAssembler_x86.hpp"

// Multiply 128 x 128 bits, using 4 pclmulqdq operations
void MacroAssembler::schoolbookAAD(int i, Register htbl, XMMRegister data,
    XMMRegister tmp0, XMMRegister tmp1, XMMRegister tmp2, XMMRegister tmp3) {
    movdqu(xmm15, Address(htbl, i * 16));
    vpclmulhqlqdq(tmp3, data, xmm15); // 0x01
    vpxor(tmp2, tmp2, tmp3, Assembler::AVX_128bit);
    vpclmulldq(tmp3, data, xmm15); // 0x00
    vpxor(tmp0, tmp0, tmp3, Assembler::AVX_128bit);
    vpclmulhdq(tmp3, data, xmm15); // 0x11
    vpxor(tmp1, tmp1, tmp3, Assembler::AVX_128bit);
    vpclmullqhqdq(tmp3, data, xmm15); // 0x10
    vpxor(tmp2, tmp2, tmp3, Assembler::AVX_128bit);
}

// Multiply two 128 bit numbers resulting in a 256 bit value
// Result of the multiplication followed by reduction stored in state
void MacroAssembler::gfmul(XMMRegister tmp0, XMMRegister state) {
    const XMMRegister tmp1 = xmm4;
    const XMMRegister tmp2 = xmm5;
    const XMMRegister tmp3 = xmm6;
    const XMMRegister tmp4 = xmm7;

    vpclmulldq(tmp1, state, tmp0); //0x00  (a0 * b0)
    vpclmulhdq(tmp4, state, tmp0);//0x11 (a1 * b1)
    vpclmullqhqdq(tmp2, state, tmp0);//0x10 (a1 * b0)
    vpclmulhqlqdq(tmp3, state, tmp0); //0x01 (a0 * b1)

    vpxor(tmp2, tmp2, tmp3, Assembler::AVX_128bit); // (a0 * b1) + (a1 * b0)

    vpslldq(tmp3, tmp2, 8, Assembler::AVX_128bit);
    vpsrldq(tmp2, tmp2, 8, Assembler::AVX_128bit);
    vpxor(tmp1, tmp1, tmp3, Assembler::AVX_128bit); // tmp1 and tmp4 hold the result
    vpxor(tmp4, tmp4, tmp2, Assembler::AVX_128bit); // of carryless multiplication
    // Follows the reduction technique mentioned in 
    // Shift-XOR reduction described in Gueron-Kounavis May 2010
    // First phase of reduction
    //
    vpslld(xmm8, tmp1, 31, Assembler::AVX_128bit); // packed right shift shifting << 31
    vpslld(xmm9, tmp1, 30, Assembler::AVX_128bit); // packed right shift shifting << 30
    vpslld(xmm10, tmp1, 25, Assembler::AVX_128bit);// packed right shift shifting << 25
    // xor the shifted versions
    vpxor(xmm8, xmm8, xmm9, Assembler::AVX_128bit);
    vpxor(xmm8, xmm8, xmm10, Assembler::AVX_128bit);
    vpslldq(xmm9, xmm8, 12, Assembler::AVX_128bit);
    vpsrldq(xmm8, xmm8, 4, Assembler::AVX_128bit);
    vpxor(tmp1, tmp1, xmm9, Assembler::AVX_128bit);// first phase of the reduction complete
    //
    // Second phase of the reduction
    //
    vpsrld(xmm9, tmp1, 1, Assembler::AVX_128bit);// packed left shifting >> 1
    vpsrld(xmm10, tmp1, 2, Assembler::AVX_128bit);// packed left shifting >> 2
    vpsrld(xmm11, tmp1, 7, Assembler::AVX_128bit);// packed left shifting >> 7
    vpxor(xmm9, xmm9, xmm10, Assembler::AVX_128bit);// xor the shifted versions
    vpxor(xmm9, xmm9, xmm11, Assembler::AVX_128bit);
    vpxor(xmm9, xmm9, xmm8, Assembler::AVX_128bit);
    vpxor(tmp1, tmp1, xmm9, Assembler::AVX_128bit);
    vpxor(state, tmp4, tmp1, Assembler::AVX_128bit);// the result is in state
    ret(0);
}

// This method takes in the subkey after expansion and generates 16 * 8 powers of subkey H using GFMUL operation.
// The powers are used for carry-less multiplication in scalar multiblock ghash operations.
void MacroAssembler::generateHtbl(Register htbl) {
    const XMMRegister t = xmm0;
    const XMMRegister tmp0 = xmm1;
    Label GFMUL;
    // load the original subkey hash
    movdqu(t, Address(htbl, 0));
    // shuffle using long swap mask
    movdqu(xmm10, ExternalAddress(StubRoutines::x86::ghash_long_swap_mask_addr()));
    vpshufb(t, t, xmm10, Assembler::AVX_128bit);
    //Save the shuffled mask as the first htbl entry
    movdqu(Address(htbl, 0 * 16), t);
    movdqu(tmp0, t);
    // Compute H' = GFMUL(H, 2)
    vpsrld(xmm3, t, 7, Assembler::AVX_128bit);
    movdqu(xmm4, ExternalAddress(StubRoutines::x86::ghash_shufflemask_addr()));
    vpshufb(xmm3, xmm3, xmm4, Assembler::AVX_128bit);
    movl(rax, 0xff00);
    movdl(xmm4, rax);
    vpshufb(xmm4, xmm4, xmm3, Assembler::AVX_128bit);
    movdqu(xmm5, ExternalAddress(StubRoutines::x86::ghash_polynomial_addr()));
    vpand(xmm5, xmm5, xmm4, Assembler::AVX_128bit);
    vpsrld(xmm3, t, 31, Assembler::AVX_128bit);
    vpslld(xmm4, t, 1, Assembler::AVX_128bit);
    vpslldq(xmm3, xmm3, 4, Assembler::AVX_128bit);
    vpxor(t, xmm4, xmm3, Assembler::AVX_128bit);// t holds p(x) <<1 or H * 2

    //Adding p(x)<<1 to xmm5 which holds the reduction polynomial
    vpxor(t, t, xmm5, Assembler::AVX_128bit);
    // tmp0 and t hold H. Now we compute powers of H by using GFMUL(H, H)
    movdqu(tmp0, t);
    // store GFMUL(H,2)
    movdqu(Address(htbl, 1 * 16), t); // H * 2
    call(GFMUL, relocInfo::none);
    movdqu(Address(htbl, 2 * 16), t); //H ^ 2 * 2
    call(GFMUL, relocInfo::none);
    movdqu(Address(htbl, 3 * 16), t); //H ^ 3 * 2
    call(GFMUL, relocInfo::none);
    movdqu(Address(htbl, 4 * 16), t); //H ^ 4 * 2
    call(GFMUL, relocInfo::none);
    movdqu(Address(htbl, 5 * 16), t); //H ^ 5 * 2
    call(GFMUL, relocInfo::none);
    movdqu(Address(htbl, 6 * 16), t); //H ^ 6 * 2
    call(GFMUL, relocInfo::none);
    movdqu(Address(htbl, 7 * 16), t); //H ^ 7 * 2
    call(GFMUL, relocInfo::none);
    movdqu(Address(htbl, 8 * 16), t); //H ^ 8 * 2

    ret(0);
    bind(GFMUL);
    gfmul(tmp0, t);
}

// Multiblock and single block GHASH computation using Shift XOR reduction technique
void MacroAssembler::avx_ghash(Register input_state, Register htbl,
    Register input_data, Register blocks) {

    // temporary variables to hold input data and input state
    const XMMRegister data = xmm1;
    const XMMRegister state = xmm0;
    // temporary variables to hold intermediate results
    const XMMRegister tmp0 = xmm3;
    const XMMRegister tmp1 = xmm4;
    const XMMRegister tmp2 = xmm5;
    const XMMRegister tmp3 = xmm6;
    const XMMRegister tmp4 = xmm7;
    // temporary variables to hold byte and long swap masks
    const XMMRegister bswap_mask = xmm2;
    const XMMRegister lswap_mask = xmm14;

    Label GENERATE_HTBL, BEGIN_PROCESS, GHASH_LOOP, BLOCK8_REDUCTION,
          ONE_BLK_INIT, PROCESS_1_BLOCK, PROCESS_8_BLOCKS, SAVE_STATE, EXIT_GHASH;

    testptr(blocks, blocks);
    jcc(Assembler::zero, EXIT_GHASH);

    // Check if Hashtable has been already generated
    movdqu(tmp2, Address(htbl, 2 * 16));
    ptest(tmp2, tmp2);
    jcc(Assembler::notZero, BEGIN_PROCESS);
    call(GENERATE_HTBL, relocInfo::none);

    // Shuffle the input state
    bind(BEGIN_PROCESS);
    movdqu(lswap_mask, ExternalAddress(StubRoutines::x86::ghash_long_swap_mask_addr()));
    movdqu(state, Address(input_state, 0));
    vpshufb(state, state, lswap_mask, Assembler::AVX_128bit);

    //Do 8 multiplies followed by a reduction processing 8 blocks of data at a time
    //Each block = 16 bytes.
    bind(PROCESS_8_BLOCKS);
    cmpl(blocks, 8);
    jcc(Assembler::below, ONE_BLK_INIT);
    subl(blocks, 8);
    movdqu(bswap_mask, ExternalAddress(StubRoutines::x86::ghash_byte_swap_mask_addr()));
    movdqu(data, Address(input_data, 16 * 7));
    vpshufb(data, data, bswap_mask, Assembler::AVX_128bit);
    //Loading 1*16 as calculated powers of H required starts at that location.
    movdqu(xmm15, Address(htbl, 1 * 16));
    //Perform carryless multiplication of (H*2, data block #7)
    vpclmulhqlqdq(tmp2, data, xmm15);//a0 * b1
    vpclmulldq(tmp0, data, xmm15);//a0 * b0
    vpclmulhdq(tmp1, data, xmm15);//a1 * b1
    vpclmullqhqdq(tmp3, data, xmm15);//a1* b0
    vpxor(tmp2, tmp2, tmp3, Assembler::AVX_128bit);// (a0 * b1) + (a1 * b0)

    movdqu(data, Address(input_data, 16 * 6));
    vpshufb(data, data, bswap_mask, Assembler::AVX_128bit);
    // Perform carryless multiplication of (H^2 * 2, data block #6)
    schoolbookAAD(2, htbl, data, tmp0, tmp1, tmp2, tmp3);

    movdqu(data, Address(input_data, 16 * 5));
    vpshufb(data, data, bswap_mask, Assembler::AVX_128bit);
    // Perform carryless multiplication of (H^3 * 2, data block #5)
    schoolbookAAD(3, htbl, data, tmp0, tmp1, tmp2, tmp3);
    movdqu(data, Address(input_data, 16 * 4));
    vpshufb(data, data, bswap_mask, Assembler::AVX_128bit);
    // Perform carryless multiplication of (H^4 * 2, data block #4)
    schoolbookAAD(4, htbl, data, tmp0, tmp1, tmp2, tmp3);
    movdqu(data, Address(input_data, 16 * 3));
    vpshufb(data, data, bswap_mask, Assembler::AVX_128bit);
    // Perform carryless multiplication of (H^5 * 2, data block #3)
    schoolbookAAD(5, htbl, data, tmp0, tmp1, tmp2, tmp3);
    movdqu(data, Address(input_data, 16 * 2));
    vpshufb(data, data, bswap_mask, Assembler::AVX_128bit);
    // Perform carryless multiplication of (H^6 * 2, data block #2)
    schoolbookAAD(6, htbl, data, tmp0, tmp1, tmp2, tmp3);
    movdqu(data, Address(input_data, 16 * 1));
    vpshufb(data, data, bswap_mask, Assembler::AVX_128bit);
    // Perform carryless multiplication of (H^7 * 2, data block #1)
    schoolbookAAD(7, htbl, data, tmp0, tmp1, tmp2, tmp3);
    movdqu(data, Address(input_data, 16 * 0));
    // xor data block#0 with input state before perfoming carry-less multiplication
    vpshufb(data, data, bswap_mask, Assembler::AVX_128bit);
    vpxor(data, data, state, Assembler::AVX_128bit);
    // Perform carryless multiplication of (H^8 * 2, data block #0)
    schoolbookAAD(8, htbl, data, tmp0, tmp1, tmp2, tmp3);
    vpslldq(tmp3, tmp2, 8, Assembler::AVX_128bit);
    vpsrldq(tmp2, tmp2, 8, Assembler::AVX_128bit);
    vpxor(tmp0, tmp0, tmp3, Assembler::AVX_128bit);// tmp0, tmp1 contains aggregated results of 
    vpxor(tmp1, tmp1, tmp2, Assembler::AVX_128bit);// the multiplication operation

    // we have the 2 128-bit partially accumulated multiplication results in tmp0:tmp1
    // with higher 128-bit in tmp1 and lower 128-bit in corresponding tmp0
    // Follows the reduction technique mentioned in 
    // Shift-XOR reduction described in Gueron-Kounavis May 2010
    bind(BLOCK8_REDUCTION);
    // First Phase of the reduction
    vpslld(xmm8, tmp0, 31, Assembler::AVX_128bit); // packed right shifting << 31
    vpslld(xmm9, tmp0, 30, Assembler::AVX_128bit); // packed right shifting << 30
    vpslld(xmm10, tmp0, 25, Assembler::AVX_128bit); // packed right shifting << 25
    // xor the shifted versions
    vpxor(xmm8, xmm8, xmm10, Assembler::AVX_128bit);
    vpxor(xmm8, xmm8, xmm9, Assembler::AVX_128bit);

    vpslldq(xmm9, xmm8, 12, Assembler::AVX_128bit);
    vpsrldq(xmm8, xmm8, 4, Assembler::AVX_128bit);

    vpxor(tmp0, tmp0, xmm9, Assembler::AVX_128bit); // first phase of reduction is complete
    // second phase of the reduction
    vpsrld(xmm9, tmp0, 1, Assembler::AVX_128bit); // packed left shifting >> 1
    vpsrld(xmm10, tmp0, 2, Assembler::AVX_128bit); // packed left shifting >> 2
    vpsrld(tmp2, tmp0, 7, Assembler::AVX_128bit); // packed left shifting >> 7
    // xor the shifted versions
    vpxor(xmm9, xmm9, xmm10, Assembler::AVX_128bit);
    vpxor(xmm9, xmm9, tmp2, Assembler::AVX_128bit);
    vpxor(xmm9, xmm9, xmm8, Assembler::AVX_128bit);
    vpxor(tmp0, xmm9, tmp0, Assembler::AVX_128bit);
    // Final result is in state
    vpxor(state, tmp0, tmp1, Assembler::AVX_128bit);

    lea(input_data, Address(input_data, 16 * 8));
    jmp(PROCESS_8_BLOCKS);

    // Since this is one block operation we will only use H * 2 i.e. the first power of H
    bind(ONE_BLK_INIT);
    movdqu(tmp0, Address(htbl, 1 * 16));
    movdqu(bswap_mask, ExternalAddress(StubRoutines::x86::ghash_byte_swap_mask_addr()));

    //Do one (128 bit x 128 bit) carry-less multiplication at a time followed by a reduction.
    bind(PROCESS_1_BLOCK);
    cmpl(blocks, 0);
    jcc(Assembler::equal, SAVE_STATE);
    subl(blocks, 1);
    movdqu(data, Address(input_data, 0));
    vpshufb(data, data, bswap_mask, Assembler::AVX_128bit);
    vpxor(state, state, data, Assembler::AVX_128bit);
    // gfmul(H*2, state)
    call(GHASH_LOOP, relocInfo::none);
    addptr(input_data, 16);
    jmp(PROCESS_1_BLOCK);

    bind(SAVE_STATE);
    vpshufb(state, state, lswap_mask, Assembler::AVX_128bit);
    movdqu(Address(input_state, 0), state);
    jmp(EXIT_GHASH);

    bind(GHASH_LOOP);
    gfmul(tmp0, state);
    bind(GENERATE_HTBL);
    generateHtbl(htbl);

    bind(EXIT_GHASH);
    // zero out xmm registers used for Htbl storage
    vpxor(xmm0, xmm0, xmm0, Assembler::AVX_128bit);
    vpxor(xmm1, xmm1, xmm1, Assembler::AVX_128bit);
    vpxor(xmm3, xmm3, xmm3, Assembler::AVX_128bit);
    vpxor(xmm15, xmm15, xmm15, Assembler::AVX_128bit);
}