systemd-boot small font HiDPI workaround

uefi_hidpi.c

#include <efi.h>
#include <efilib.h>

#define SHELL_INTERFACE_PROTOCOL \
{ \
	0x47c7b223, 0xc42a, 0x11d2, { 0x8e, 0x57, 0x0, 0xa0, 0xc9, 0x69, 0x72, \
			0x3b } \
}

typedef struct _EFI_SHELL_ARG_INFO {
	UINT32  Attributes;
} EFI_SHELL_ARG_INFO;

typedef struct _EFI_SHELL_INTERFACE {
	//
	// Handle back to original image handle & image info
	//
	EFI_HANDLE                ImageHandle;
	EFI_LOADED_IMAGE_PROTOCOL *Info;

	//
	// Parsed arg list
	//
	CHAR16                    **Argv;
	UINTN                     Argc;

	//
	// Storage for file redirection args after parsing
	//
	CHAR16                    **RedirArgv;
	UINTN                     RedirArgc;

	//
	// A file style handle for console io
	//
	EFI_FILE_HANDLE           StdIn;
	EFI_FILE_HANDLE           StdOut;
	EFI_FILE_HANDLE           StdErr;
	EFI_SHELL_ARG_INFO        *ArgInfo;
	BOOLEAN                   EchoOn;
} EFI_SHELL_INTERFACE;

EFI_STATUS
EFIAPI
efi_main (EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable) {
	EFI_STATUS Status;
	EFI_INPUT_KEY Key;

	InitializeLib(ImageHandle, SystemTable);

	/* Change screen to mode 2 */
//	uefi_call_wrapper(SystemTable->ConOut->SetMode, 2, SystemTable->ConOut,
//			(UINTN)2);

	Print(L"Hello, world!\n");

	EFI_SHELL_INTERFACE Interface = {ImageHandle};
	EFI_GUID ShellInterfaceProtocol  = SHELL_INTERFACE_PROTOCOL;

	Print(L"Installing shell interface protocol.\n");

	/* This call switches the screen resolution in my machine
	 * (Toshiba P50t), as if calling ST->ConOut->SetMode(2) (see commented
	 * code above). The default mode 0 is 80x25 and the screen resolution is
	 * 4k (visible area is 640x475 in the middle of the screen, text is
	 * very small). Mode 2 is 100x31 filling the whole display area, so the
	 * screen resolution is  800x600, making the text much larger. */
	Status = LibInstallProtocolInterfaces(&ImageHandle,
			&ShellInterfaceProtocol, &Interface, NULL);

	if (Status != EFI_SUCCESS)
		Print(L"Install error.\n");
	else
		Print(L"Installed.\n");


	Print(L"Press any key to continue.");
	Pause();
	uefi_call_wrapper(ST->ConIn->ReadKeyStroke, 2, ST->ConIn, &Key);
	Print(L"\n");

	return EFI_SUCCESS;
}