如何使用 gnu-efi 编译 uefi 应用程序？

Question

我尝试使用 gnu-efi 编译 uefi 代码。但是我不明白如何编译我的 uefi 应用程序代码。

我得到gnu-efi 3.0.2，解压并输入make && make install。我写你好世界代码：

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

EFI_STATUS efi_main (EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable) {
    InitializeLib(ImageHandle, SystemTable);
    Print(L"Hello, world!\n");

    return EFI_SUCCESS;
}

我的 OS 是 Ubuntu 15.04.

Answer 1

包括 gnu-efi 文件
```
#include <efi.h> 
#include <efilib.h>
```
看起来你的包含被 SO
创建 make 文件；

If you were building a "Hello, World" program for Linux in a Linux environment, you could compile it without a Makefile. Building the program in Linux for EFI, though, is essentially a cross-compilation operation. As such, it necessitates using unusual compilation and linker options, as well as a post-linking operation to convert the program into a form that the EFI will accept. Although you could type all the relevant commands by hand, a Makefile helps a lot.

ARCH            = $(shell uname -m | sed s,i[3456789]86,ia32,)

OBJS            = main.o
TARGET          = hello.efi

EFIINC          = /usr/include/efi
EFIINCS         = -I$(EFIINC) -I$(EFIINC)/$(ARCH) -I$(EFIINC)/protocol
LIB             = /usr/lib64
EFILIB          = /usr/lib64/gnuefi
EFI_CRT_OBJS    = $(EFILIB)/crt0-efi-$(ARCH).o
EFI_LDS         = $(EFILIB)/elf_$(ARCH)_efi.lds

CFLAGS          = $(EFIINCS) -fno-stack-protector -fpic \
          -fshort-wchar -mno-red-zone -Wall 
ifeq ($(ARCH),x86_64)
  CFLAGS += -DEFI_FUNCTION_WRAPPER
endif

LDFLAGS         = -nostdlib -znocombreloc -T $(EFI_LDS) -shared \
          -Bsymbolic -L $(EFILIB) -L $(LIB) $(EFI_CRT_OBJS) 

all: $(TARGET)

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

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

参考：

http://www.rodsbooks.com/efi-programming/hello.html

Answer 2

在 Ubuntu 18.04 中，这两行：

LIB             = /usr/lib64

EFILIB          = /usr/lib64/gnuefi

需要改为：

LIB             = /usr/lib

EFILIB          = /usr/lib

如何使用 gnu-efi 编译 uefi 应用程序？

How to compile uefi application using gnu-efi?

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