x86: Set up toolchain flags for running as EFI application

Adjust the toolchain flags to build U-Boot as a relocatable shared library,
as required by EFI.

Signed-off-by: Ben Stoltz <stoltz@google.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>

arch/x86/config.mk

@@ -8,19 +8,43 @@
 CONFIG_STANDALONE_LOAD_ADDR ?= 0x40000
 
 PLATFORM_CPPFLAGS += -fno-strict-aliasing
-PLATFORM_CPPFLAGS += -mregparm=3
 PLATFORM_CPPFLAGS += -fomit-frame-pointer
 PF_CPPFLAGS_X86   := $(call cc-option, -fno-toplevel-reorder, \
 		       $(call cc-option, -fno-unit-at-a-time)) \
 		     $(call cc-option, -mpreferred-stack-boundary=2)
+
 PLATFORM_CPPFLAGS += $(PF_CPPFLAGS_X86)
 PLATFORM_CPPFLAGS += -fno-dwarf2-cfi-asm
 PLATFORM_CPPFLAGS += -march=i386 -m32
 
 PLATFORM_RELFLAGS += -ffunction-sections -fvisibility=hidden
 
-PLATFORM_LDFLAGS += --emit-relocs -Bsymbolic -Bsymbolic-functions -m elf_i386
+PLATFORM_LDFLAGS += -Bsymbolic -Bsymbolic-functions -m elf_i386
 
-LDFLAGS_FINAL += --gc-sections -pie
 LDFLAGS_FINAL += --wrap=__divdi3 --wrap=__udivdi3
 LDFLAGS_FINAL += --wrap=__moddi3 --wrap=__umoddi3
+
+OBJCOPYFLAGS_EFI := -j .text -j .sdata -j .data -j .dynamic -j .dynsym \
+	-j .rel -j .rela -j .reloc
+
+CFLAGS_NON_EFI := -mregparm=3
+CFLAGS_EFI := -fpic -fshort-wchar
+
+EFIARCH = ia32
+
+LDSCRIPT_EFI := $(srctree)/$(CPUDIR)/efi/elf_$(EFIARCH)_efi.lds
+OBJCOPYFLAGS_EFI += --target=efi-app-$(EFIARCH)
+
+ifeq ($(CONFIG_EFI_APP),y)
+
+PLATFORM_CPPFLAGS += $(CFLAGS_EFI)
+LDFLAGS_FINAL += -znocombreloc -shared
+LDSCRIPT := $(LDSCRIPT_EFI)
+
+else
+
+PLATFORM_CPPFLAGS += $(CFLAGS_NON_EFI)
+PLATFORM_LDFLAGS += --emit-relocs
+LDFLAGS_FINAL += --gc-sections -pie
+
+endif