ksOS/Bootloader/Source/main.c

#include "uefi/uefi.h" // IWYU pragma: keep
#include "../../Common/bootinfo.h"

void print(wchar_t* msg) {
    ST->ConOut->OutputString(ST->ConOut, msg);
}

efi_status_t die() {
    while(1) __asm__ volatile("wfi");
    return EFI_ABORTED;
}

int compare_guid(efi_guid_t* a, efi_guid_t* b) {
    uint8_t* p1 = (uint8_t*)a;
    uint8_t* p2 = (uint8_t*)b;
    for (int i = 0; i < 16; i++) {
        if (p1[i] != p2[i]) return 0;
    }
    return 1;
}

int main()
{
    efi_gop_t* gop = NULL;
    efi_guid_t gop_guid = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
    ST->BootServices->LocateProtocol(&gop_guid, 0, (void**)&gop);

    efi_guid_t dtb_guid = {0xb1b621d5, 0xf19c, 0x41a5, {0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0}};
    void* dtbAddress = NULL;

    for (uintn_t i = 0; i < ST->NumberOfTableEntries; i++) {
        if (compare_guid(&ST->ConfigurationTable[i].VendorGuid, &dtb_guid)) {
            dtbAddress = ST->ConfigurationTable[i].VendorTable;
            break;
        }
    }

    if (!dtbAddress) {
        print(L"Failed to find DTB!\r\n");
        return die();
    }

    efi_loaded_image_protocol_t* loaded_image;
    efi_guid_t lip_guid = EFI_LOADED_IMAGE_PROTOCOL_GUID;
    gBS->HandleProtocol(IM, &lip_guid, (void**)&loaded_image);

    efi_simple_file_system_protocol_t* fs;
    efi_guid_t sfsp_guid = EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID;
    gBS->HandleProtocol(loaded_image->DeviceHandle, &sfsp_guid, (void**)&fs);

    efi_file_handle_t* root;
    fs->OpenVolume(fs, &root);

    efi_file_handle_t* kernel_file;
    uintn_t kinfo_size = 0;
    efi_file_info_t* kfile_info = NULL;
    efi_guid_t fi_guid = EFI_FILE_INFO_GUID;

    efi_status_t status = root->Open(root, &kernel_file, L"ksOSKernel.bin", EFI_FILE_MODE_READ, 0);
    if (EFI_ERROR(status)) {
        print(L"Cant find ksOSKernel.bin\r\n");
        return die();
    }

    status = kernel_file->GetInfo(kernel_file, &fi_guid, &kinfo_size, NULL);
    if (status == EFI_BUFFER_TOO_SMALL) { 
        gBS->AllocatePool(EfiLoaderData, kinfo_size, (void**)&kfile_info);
        status = kernel_file->GetInfo(kernel_file, &fi_guid, &kinfo_size, kfile_info);
    }

    uint64_t kernel_size = kfile_info->FileSize;
    uintn_t kernel_size_read = (uintn_t)kernel_size;
    
    uintn_t kernel_pages = (kernel_size + 0xFFF) / 0x1000;
    efi_physical_address_t kernel_addr = 0; 
    
    status = gBS->AllocatePages(AllocateAnyPages, EfiLoaderData, kernel_pages, &kernel_addr);
    if (EFI_ERROR(status)) {
        print(L"Failed to allocate ANY memory for kernel!\r\n");
        return die();
    }

    kernel_file->Read(kernel_file, &kernel_size_read, (void*)kernel_addr); \
    printf("Kernel loaded at %p\r\n", (void*)kernel_addr);

    Bootinfo* bootInfo = (Bootinfo*)malloc(sizeof(Bootinfo));
    bootInfo->magic = BOOTINFO_MAGIC;

    bootInfo->kernelInfo.kernelAddress = (void*)kernel_addr;
    bootInfo->kernelInfo.kernelSize = kernel_size;

    bootInfo->framebuffer.base = (BIUInt32*)gop->Mode->FrameBufferBase;
    bootInfo->framebuffer.baseSize = gop->Mode->FrameBufferSize;
    bootInfo->framebuffer.height = gop->Mode->Information->VerticalResolution;
    bootInfo->framebuffer.width = gop->Mode->Information->HorizontalResolution;
    bootInfo->framebuffer.pitch = gop->Mode->Information->PixelsPerScanLine;

    bootInfo->dtb = dtbAddress;
    printf("DTB located at: %p\r\n", (void*)dtbAddress);
    
    uintn_t map_size = 0;
    efi_memory_descriptor_t *map = NULL;
    uintn_t map_key;
    uintn_t desc_size;
    uint32_t desc_version;


    print(L"Almost ready to jump :D. Working with memory map\r\n");

    gBS->GetMemoryMap(&map_size, NULL, &map_key, &desc_size, &desc_version);
    map_size += 4096;
    // woah letsgoo
    status = gBS->AllocatePool(EfiLoaderData, map_size, (void**)&map);
    if (EFI_ERROR(status)) {
        print(L"Failed to allocate pool\r\n");
    }

    do {
        status = gBS->GetMemoryMap(&map_size, map, &map_key, &desc_size, &desc_version);
        if (EFI_ERROR(status)) {
            break;
        }
        
        bootInfo->memoryMap.descriptorSize = desc_size;
        bootInfo->memoryMap.descriptorVersion = desc_version;
        bootInfo->memoryMap.mapSize = map_size;
        bootInfo->memoryMap.mapKey = map_key;
        bootInfo->memoryMap.map = map;

        status = gBS->ExitBootServices(IM, map_key);
        if (status == EFI_SUCCESS) {
            break; // FUCK OFF;
        }
        map_size += 2 * desc_size; 
    } while (EFI_ERROR(status));

    typedef void (__attribute__((sysv_abi)) *kentry)(Bootinfo*);
    kentry kmain = (kentry)kernel_addr;

    kmain(bootInfo); // yay! :D


    return EFI_SUCCESS;
}