/* SPDX-License-Identifier: Apache-2.0 OR BSD-2-Clause */
//
// This file is dual-licensed, meaning that you can use it under your
// choice of either of the following two licenses:
//
// Copyright 2023 The OpenSSL Project Authors. All Rights Reserved.
//
// Licensed under the Apache License 2.0 (the "License"). You can obtain
// a copy in the file LICENSE in the source distribution or at
// https://www.openssl.org/source/license.html
//
// or
//
// Copyright (c) 2023, Christoph Müllner <christoph.muellner@vrull.eu>
// Copyright (c) 2023, Phoebe Chen <phoebe.chen@sifive.com>
// Copyright 2024 Google LLC
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// The generated code of this file depends on the following RISC-V extensions:
// - RV64I
// - RISC-V Vector ('V') with VLEN >= 128
// - RISC-V Vector SHA-2 Secure Hash extension ('Zvknha' or 'Zvknhb')
// - RISC-V Vector Cryptography Bit-manipulation extension ('Zvkb')

#include <linux/linkage.h>

.text
.option arch, +zvknha, +zvkb

#define STATEP          a0
#define DATA            a1
#define NUM_BLOCKS      a2

#define STATEP_C        a3

#define MASK            v0
#define INDICES         v1
#define W0              v2
#define W1              v3
#define W2              v4
#define W3              v5
#define VTMP            v6
#define FEBA            v7
#define HGDC            v8
#define K0              v10
#define K1              v11
#define K2              v12
#define K3              v13
#define K4              v14
#define K5              v15
#define K6              v16
#define K7              v17
#define K8              v18
#define K9              v19
#define K10             v20
#define K11             v21
#define K12             v22
#define K13             v23
#define K14             v24
#define K15             v25
#define PREV_FEBA       v26
#define PREV_HGDC       v27

// Do 4 rounds of SHA-256.  w0 contains the current 4 message schedule words.
//
// If not all the message schedule words have been computed yet, then this also
// computes 4 more message schedule words.  w1-w3 contain the next 3 groups of 4
// message schedule words; this macro computes the group after w3 and writes it
// to w0.  This means that the next (w0, w1, w2, w3) is the current (w1, w2, w3,
// w0), so the caller must cycle through the registers accordingly.
.macro  sha256_4rounds  last, k, w0, w1, w2, w3
        vadd.vv         VTMP, \k, \w0
        vsha2cl.vv      HGDC, FEBA, VTMP
        vsha2ch.vv      FEBA, HGDC, VTMP
.if !\last
        vmerge.vvm      VTMP, \w2, \w1, MASK
        vsha2ms.vv      \w0, VTMP, \w3
.endif
.endm

.macro  sha256_16rounds last, k0, k1, k2, k3
        sha256_4rounds  \last, \k0, W0, W1, W2, W3
        sha256_4rounds  \last, \k1, W1, W2, W3, W0
        sha256_4rounds  \last, \k2, W2, W3, W0, W1
        sha256_4rounds  \last, \k3, W3, W0, W1, W2
.endm

// void sha256_transform_zvknha_or_zvknhb_zvkb(struct sha256_block_state *state,
//                                             const u8 *data, size_t nblocks);
SYM_FUNC_START(sha256_transform_zvknha_or_zvknhb_zvkb)

        // Load the round constants into K0-K15.
        vsetivli        zero, 4, e32, m1, ta, ma
        la              t0, K256
        vle32.v         K0, (t0)
        addi            t0, t0, 16
        vle32.v         K1, (t0)
        addi            t0, t0, 16
        vle32.v         K2, (t0)
        addi            t0, t0, 16
        vle32.v         K3, (t0)
        addi            t0, t0, 16
        vle32.v         K4, (t0)
        addi            t0, t0, 16
        vle32.v         K5, (t0)
        addi            t0, t0, 16
        vle32.v         K6, (t0)
        addi            t0, t0, 16
        vle32.v         K7, (t0)
        addi            t0, t0, 16
        vle32.v         K8, (t0)
        addi            t0, t0, 16
        vle32.v         K9, (t0)
        addi            t0, t0, 16
        vle32.v         K10, (t0)
        addi            t0, t0, 16
        vle32.v         K11, (t0)
        addi            t0, t0, 16
        vle32.v         K12, (t0)
        addi            t0, t0, 16
        vle32.v         K13, (t0)
        addi            t0, t0, 16
        vle32.v         K14, (t0)
        addi            t0, t0, 16
        vle32.v         K15, (t0)

        // Setup mask for the vmerge to replace the first word (idx==0) in
        // message scheduling.  There are 4 words, so an 8-bit mask suffices.
        vsetivli        zero, 1, e8, m1, ta, ma
        vmv.v.i         MASK, 0x01

        // Load the state.  The state is stored as {a,b,c,d,e,f,g,h}, but we
        // need {f,e,b,a},{h,g,d,c}.  The dst vtype is e32m1 and the index vtype
        // is e8mf4.  We use index-load with the i8 indices {20, 16, 4, 0},
        // loaded using the 32-bit little endian value 0x00041014.
        li              t0, 0x00041014
        vsetivli        zero, 1, e32, m1, ta, ma
        vmv.v.x         INDICES, t0
        addi            STATEP_C, STATEP, 8
        vsetivli        zero, 4, e32, m1, ta, ma
        vluxei8.v       FEBA, (STATEP), INDICES
        vluxei8.v       HGDC, (STATEP_C), INDICES

.Lnext_block:
        addi            NUM_BLOCKS, NUM_BLOCKS, -1

        // Save the previous state, as it's needed later.
        vmv.v.v         PREV_FEBA, FEBA
        vmv.v.v         PREV_HGDC, HGDC

        // Load the next 512-bit message block and endian-swap each 32-bit word.
        vle32.v         W0, (DATA)
        vrev8.v         W0, W0
        addi            DATA, DATA, 16
        vle32.v         W1, (DATA)
        vrev8.v         W1, W1
        addi            DATA, DATA, 16
        vle32.v         W2, (DATA)
        vrev8.v         W2, W2
        addi            DATA, DATA, 16
        vle32.v         W3, (DATA)
        vrev8.v         W3, W3
        addi            DATA, DATA, 16

        // Do the 64 rounds of SHA-256.
        sha256_16rounds 0, K0, K1, K2, K3
        sha256_16rounds 0, K4, K5, K6, K7
        sha256_16rounds 0, K8, K9, K10, K11
        sha256_16rounds 1, K12, K13, K14, K15

        // Add the previous state.
        vadd.vv         FEBA, FEBA, PREV_FEBA
        vadd.vv         HGDC, HGDC, PREV_HGDC

        // Repeat if more blocks remain.
        bnez            NUM_BLOCKS, .Lnext_block

        // Store the new state and return.
        vsuxei8.v       FEBA, (STATEP), INDICES
        vsuxei8.v       HGDC, (STATEP_C), INDICES
        ret
SYM_FUNC_END(sha256_transform_zvknha_or_zvknhb_zvkb)

.section ".rodata"
.p2align 2
.type K256, @object
K256:
        .word           0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5
        .word           0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5
        .word           0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3
        .word           0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174
        .word           0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc
        .word           0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da
        .word           0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7
        .word           0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967
        .word           0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13
        .word           0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85
        .word           0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3
        .word           0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070
        .word           0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5
        .word           0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3
        .word           0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208
        .word           0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
.size K256, . - K256