Compiling C EFI application with Make and GNU-EFI, and running in QEMU

main.c

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


EFI_STATUS EFIAPI
efi_main (EFI_HANDLE image_handle, EFI_SYSTEM_TABLE* system_table)
{
    InitializeLib(image_handle, system_table);
    Print(L"Hello from the UEFI\n");
    return EFI_SUCCESS;
}

Makefile

ARCH=x86_64

OBJS=main.o
TARGET=main.efi

CC=gcc

EFI_INCLUDE_PATH=/usr/local/include/efi
EFI_INCLUDES=-I$(EFI_INCLUDE_PATH) -I$(EFI_INCLUDE_PATH)/$(ARCH) -I$(EFI_INCLUDE_PATH)/protocol

CFLAGS=$(EFI_INCLUDES) -fno-stack-protector -fpic \
		  -fshort-wchar -mno-red-zone -Wall -DEFI_FUNCTION_WRAPPER

LIB_PATH=/usr/local/lib
EFI_LIB_PATH=/usr/local/lib/
EFI_CRT_OBJS=$(EFI_LIB_PATH)/crt0-efi-$(ARCH).o
EFI_LDS=$(EFI_LIB_PATH)/elf_$(ARCH)_efi.lds

LDFLAGS=-nostdlib -znocombreloc -T $(EFI_LDS) -shared \
	  		-Bsymbolic -L $(EFI_LIB_PATH) -L $(LIB_PATH) $(EFI_CRT_OBJS) 

all: $(TARGET)

main.so: $(OBJS)
		ld $(LDFLAGS) $(OBJS) -o $@ -lefi -lgnuefi

%.o: %.c
	$(CC) -c -o $@ $< $(CFLAGS)

%.efi: %.so
	objcopy -j .text -j .sdata -j .data -j .dynamic \
			-j .dynsym  -j .rel -j .rela -j .reloc \
			--target=efi-app-$(ARCH) $^ $@

clean:
	rm *.so *.o *.efi

run.sh

#!/bin/bash

RUN_PATH=build/qemu

OVMF_DISK_IMG=/usr/share/ovmf/OVMF.fd
BINARY_PATH=main.efi
DISK_PATH=${RUN_PATH}/uefi.img


# clean previous
make clean

# build
make

# make image
mkdir -p ${RUN_PATH}

## prepare disk image


## prepare files for efi partition (application binary + startup script)
dd if=/dev/zero of=/tmp/part.img bs=512 count=91669
mformat -i /tmp/part.img -h 32 -t 32 -n 64 -c 1

mcopy -i /tmp/part.img ${BINARY_PATH} ::app.efi
echo app.efi > startup.nsh
mcopy -i /tmp/part.img startup.nsh ::/

## make full image (with format and efi partition)
dd if=/dev/zero of=${DISK_PATH} bs=512 count=93750
parted ${DISK_PATH} -s -a minimal mklabel gpt
parted ${DISK_PATH} -s -a minimal mkpart EFI FAT16 2048s 93716s
parted ${DISK_PATH} -s -a minimal toggle 1 boot
## copy files into the image
dd if=/tmp/part.img of=${DISK_PATH} bs=512 count=91669 seek=2048 conv=notrunc

# run
qemu-system-x86_64 \
  -cpu qemu64 \
  -enable-kvm \
  -net none \
  -drive if=pflash,format=raw,unit=0,file=${OVMF_DISK_IMG},readonly=on \
  -drive if=ide,format=raw,file=${DISK_PATH}