Luma3DS-3GX/source/firm.c

/*
*   firm.c
*       by Reisyukaku
*   Copyright (c) 2015 All Rights Reserved
*/

#include "firm.h"
#include "patches.h"
#include "memory.h"
#include "fs.h"
#include "emunand.h"
#include "crypto.h"

firmHeader *firmLocation = (firmHeader *)0x24000000;
firmSectionHeader *section;
u32 firmSize = 0;
u8  mode = 1,
    console = 1;
u16 pressed;

//Load firm into FCRAM
u8 loadFirm(void){

    if(PDN_MPCORE_CFG == 1) console = 0;
    pressed = HID_PAD;
    section = firmLocation->section;

    //If L and R are pressed, boot SysNAND with the NAND FIRM
    if((pressed & BUTTON_L1R1) == BUTTON_L1R1){
        mode = 0;
        //Read FIRM from NAND and write to FCRAM
        firmSize = console ? 0xF2C00 : 0xE9000;
        nandFirm0((u8*)firmLocation, firmSize, console);
        if(memcmp((u8*)firmLocation, "FIRM", 4) != 0) return 1;
    }
    //Load FIRM from SDCard
    else{
        const char firmPath[] = "/rei/firmware.bin";
        firmSize = fileSize(firmPath);
        if (!firmSize) return 1;
        fileRead((u8*)firmLocation, firmPath, firmSize);
        if((((u32)section[2].address >> 8) & 0xFF) != (console ? 0x60 : 0x68)) return 1;
    }

    if(console) arm9loader((u8*)firmLocation + section[2].offset, mode);

    return 0;
}

//Nand redirection
u8 loadEmu(void){

    u32 emuOffset = 0,
    emuHeader = 0,
    emuRead = 0,
    emuWrite = 0,
    sdmmcOffset = 0,
    mpuOffset = 0,
    emuCodeOffset = 0;

    //Read emunand code from SD
    getEmuCode(firmLocation, &emuCodeOffset, firmSize);
    const char path[] = "/rei/emunand/emunand.bin";
    u32 size = fileSize(path);
    if (!size) return 1;
    fileRead((u8*)emuCodeOffset, path, size);

    //Find and patch emunand related offsets
    u32 *pos_sdmmc = memsearch((u32*)emuCodeOffset, "SDMC", size, 4);
    u32 *pos_offset = memsearch((u32*)emuCodeOffset, "NAND", size, 4);
    u32 *pos_header = memsearch((u32*)emuCodeOffset, "NCSD", size, 4);
    getSDMMC(firmLocation, &sdmmcOffset, firmSize);
    getEmunandSect(&emuOffset, &emuHeader);
    getEmuRW(firmLocation, firmSize, &emuRead, &emuWrite);
    getMPU(firmLocation, &mpuOffset, firmSize);
    *pos_sdmmc = sdmmcOffset;
    *pos_offset = emuOffset;
    *pos_header = emuHeader;

    //Add emunand hooks
    if(!console) nandRedir[5] = 0xA4;
    memcpy((u8*)emuRead, nandRedir, sizeof(nandRedir));
    memcpy((u8*)emuWrite, nandRedir, sizeof(nandRedir));

    //Set MPU for emu code region
    memcpy((u8*)mpuOffset, mpu, sizeof(mpu));

    return 0;
}

//Patches
u8 patchFirm(void){

    //If L is pressed, boot SysNAND with the SDCard FIRM
    if(mode && !(pressed & BUTTON_L1)) if (loadEmu()) return 1;

    //Disable signature checks
    u32 sigOffset = 0,
    sigOffset2 = 0;
    getSignatures(firmLocation, firmSize, &sigOffset, &sigOffset2);
    memcpy((u8*)sigOffset, sigPat1, sizeof(sigPat1));
    memcpy((u8*)sigOffset2, sigPat2, sizeof(sigPat2));

    //Apply reboot patch and write patched FIRM
    if(!console && mode &&
       ((fileSize("/rei/reversereboot") > 0) == (pressed & BUTTON_A))){
        u32 rebootOffset = 0,
        rebootOffset2 = 0;
        getReboot(firmLocation, firmSize, &rebootOffset, &rebootOffset2);
        char path[] = "/rei/reboot/reboot1.bin";
        u32 size = fileSize(path);
        if (!size) return 1;
        fileRead((u8*)rebootOffset, path, size);
        memcpy((u8*)rebootOffset + size, L"sdmc:", 10);
        memcpy((u8*)rebootOffset + size + 10, L"" PATCHED_FIRM_PATH, sizeof(PATCHED_FIRM_PATH) * 2);
        path[18] = '2';
        size = fileSize(path);
        if (!size) return 1;
        fileRead((u8*)rebootOffset2, path, size);
        if (fileWrite((u8*)firmLocation, PATCHED_FIRM_PATH, firmSize) != 0) return 1;
    }

    return 0;
}

//Firmlaunchhax
void launchFirm(void){

    //Set MPU
    __asm__ (
        "msr cpsr_c, #0xDF\n\t"         //Set system mode, disable interrupts
        "ldr r0, =0x10000035\n\t"       //Memory area 0x10000000-0x18000000, enabled, 128MB
        "ldr r4, =0x18000035\n\t"       //Memory area 0x18000000-0x20000000, enabled, 128MB
        "mcr p15, 0, r0, c6, c3, 0\n\t" //Set memory area 3 (0x10000000-0x18000000)
        "mcr p15, 0, r4, c6, c4, 0\n\t" //Set memory area 4 (0x18000000-0x20000000)
        "mrc p15, 0, r0, c2, c0, 0\n\t" //read data cacheable bit
        "mrc p15, 0, r4, c2, c0, 1\n\t" //read inst cacheable bit
        "mrc p15, 0, r1, c3, c0, 0\n\t" //read data writeable
        "mrc p15, 0, r2, c5, c0, 2\n\t" //read data access permission
        "mrc p15, 0, r3, c5, c0, 3\n\t" //read inst access permission
        "orr r0, r0, #0x30\n\t"
        "orr r4, r4, #0x30\n\t"
        "orr r1, r1, #0x30\n\t"
        "bic r2, r2, #0xF0000\n\t"
        "bic r3, r3, #0xF0000\n\t"
        "orr r2, r2, #0x30000\n\t"
        "orr r3, r3, #0x30000\n\t"
        "mcr p15, 0, r0, c2, c0, 0\n\t" //write data cacheable bit
        "mcr p15, 0, r4, c2, c0, 1\n\t" //write inst cacheable bit
        "mcr p15, 0, r1, c3, c0, 0\n\t" //write data writeable
        "mcr p15, 0, r2, c5, c0, 2\n\t" //write data access permission
        "mcr p15, 0, r3, c5, c0, 3\n\t" //write inst access permission
        ::: "r0", "r1", "r2", "r3", "r4"
    );
    
    //Copy firm partitions to respective memory locations
    memcpy(section[0].address, (u8*)firmLocation + section[0].offset, section[0].size);
    memcpy(section[1].address, (u8*)firmLocation + section[1].offset, section[1].size);
    memcpy(section[2].address, (u8*)firmLocation + section[2].offset, section[2].size);
    *(u32 *)0x1FFFFFF8 = (u32)firmLocation->arm11Entry;
    
    //Final jump to arm9 binary
    console ? ((void (*)())0x801B01C)() : ((void (*)())firmLocation->arm9Entry)();
}