/****************************************************************************
 * Copyright (C) 2018-2020 Maschell
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ****************************************************************************/

#include <cstdint>
#include <cstdio>
#include <cstring>
#include <coreinit/cache.h>
#include <coreinit/memorymap.h>

#include "kernel.h"

/* assembly functions */
extern "C" void Syscall_0x36(void);
extern "C" void KernelPatchesRevertHook(void);
extern "C" void KernelPatches(void);

void __attribute__ ((noinline)) kern_write(void *addr, uint32_t value);


void doKernelSetup() {
    kern_write((void *) (KERN_SYSCALL_TBL_1 + (0x36 * 4)), (unsigned int) KernelPatches);
    kern_write((void *) (KERN_SYSCALL_TBL_2 + (0x36 * 4)), (unsigned int) KernelPatches);
    kern_write((void *) (KERN_SYSCALL_TBL_3 + (0x36 * 4)), (unsigned int) KernelPatches);
    kern_write((void *) (KERN_SYSCALL_TBL_4 + (0x36 * 4)), (unsigned int) KernelPatches);
    kern_write((void *) (KERN_SYSCALL_TBL_5 + (0x36 * 4)), (unsigned int) KernelPatches);

    Syscall_0x36();
}

void revertKernelHook() {
    kern_write((void *) (KERN_SYSCALL_TBL_1 + (0x36 * 4)), (unsigned int) KernelPatchesRevertHook);
    kern_write((void *) (KERN_SYSCALL_TBL_2 + (0x36 * 4)), (unsigned int) KernelPatchesRevertHook);
    kern_write((void *) (KERN_SYSCALL_TBL_3 + (0x36 * 4)), (unsigned int) KernelPatchesRevertHook);
    kern_write((void *) (KERN_SYSCALL_TBL_4 + (0x36 * 4)), (unsigned int) KernelPatchesRevertHook);
    kern_write((void *) (KERN_SYSCALL_TBL_5 + (0x36 * 4)), (unsigned int) KernelPatchesRevertHook);

    Syscall_0x36();
}

/* Write a 32-bit word with kernel permissions */
void __attribute__ ((noinline)) kern_write(void *addr, uint32_t value) {
    asm volatile (
    "li 3,1\n"
    "li 4,0\n"
    "mr 5,%1\n"
    "li 6,0\n"
    "li 7,0\n"
    "lis 8,1\n"
    "mr 9,%0\n"
    "mr %1,1\n"
    "li 0,0x3500\n"
    "sc\n"
    "nop\n"
    "mr 1,%1\n"
    :
    :    "r"(addr), "r"(value)
    :    "memory", "ctr", "lr", "0", "3", "4", "5", "6", "7", "8", "9", "10",
    "11", "12"
    );
}