169 lines
		
	
	
		
			6.6 KiB
		
	
	
	
		
			Makefile
		
	
	
	
	
	
			
		
		
	
	
			169 lines
		
	
	
		
			6.6 KiB
		
	
	
	
		
			Makefile
		
	
	
	
	
	
| # SPDX-License-Identifier: GPL-2.0
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| #
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| # The stub may be linked into the kernel proper or into a separate boot binary,
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| # but in either case, it executes before the kernel does (with MMU disabled) so
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| # things like ftrace and stack-protector are likely to cause trouble if left
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| # enabled, even if doing so doesn't break the build.
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| #
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| cflags-$(CONFIG_X86_32)		:= -march=i386
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| cflags-$(CONFIG_X86_64)		:= -mcmodel=small
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| cflags-$(CONFIG_X86)		+= -m$(BITS) -D__KERNEL__ \
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| 				   -fPIC -fno-strict-aliasing -mno-red-zone \
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| 				   -mno-mmx -mno-sse -fshort-wchar \
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| 				   -Wno-pointer-sign \
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| 				   $(call cc-disable-warning, address-of-packed-member) \
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| 				   $(call cc-disable-warning, gnu) \
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| 				   -fno-asynchronous-unwind-tables \
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| 				   $(CLANG_FLAGS)
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| 
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| # arm64 uses the full KBUILD_CFLAGS so it's necessary to explicitly
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| # disable the stackleak plugin
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| cflags-$(CONFIG_ARM64)		:= $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
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| 				   -fpie $(DISABLE_STACKLEAK_PLUGIN) \
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| 				   $(call cc-option,-mbranch-protection=none)
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| cflags-$(CONFIG_ARM)		:= $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
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| 				   -fno-builtin -fpic \
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| 				   $(call cc-option,-mno-single-pic-base)
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| cflags-$(CONFIG_RISCV)		:= $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
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| 				   -fpic -mno-relax
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| cflags-$(CONFIG_LOONGARCH)	:= $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
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| 				   -fpie
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| 
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| cflags-$(CONFIG_EFI_PARAMS_FROM_FDT)	+= -I$(srctree)/scripts/dtc/libfdt
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| 
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| KBUILD_CFLAGS			:= $(cflags-y) -Os -DDISABLE_BRANCH_PROFILING \
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| 				   -include $(srctree)/include/linux/hidden.h \
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| 				   -D__NO_FORTIFY \
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| 				   -ffreestanding \
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| 				   -fno-stack-protector \
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| 				   $(call cc-option,-fno-addrsig) \
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| 				   -D__DISABLE_EXPORTS
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| 
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| #
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| # struct randomization only makes sense for Linux internal types, which the EFI
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| # stub code never touches, so let's turn off struct randomization for the stub
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| # altogether
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| #
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| KBUILD_CFLAGS := $(filter-out $(RANDSTRUCT_CFLAGS), $(KBUILD_CFLAGS))
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| 
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| # remove SCS flags from all objects in this directory
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| KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_SCS), $(KBUILD_CFLAGS))
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| # disable CFI
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| KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_CFI), $(KBUILD_CFLAGS))
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| # disable LTO
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| KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_LTO), $(KBUILD_CFLAGS))
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| 
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| # The .data section would be renamed to .data.efistub, therefore, remove
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| # `-fdata-sections` flag from KBUILD_CFLAGS_KERNEL
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| KBUILD_CFLAGS_KERNEL := $(filter-out -fdata-sections, $(KBUILD_CFLAGS_KERNEL))
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| 
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| GCOV_PROFILE			:= n
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| # Sanitizer runtimes are unavailable and cannot be linked here.
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| KASAN_SANITIZE			:= n
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| KCSAN_SANITIZE			:= n
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| KMSAN_SANITIZE			:= n
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| UBSAN_SANITIZE			:= n
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| OBJECT_FILES_NON_STANDARD	:= y
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| 
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| # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
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| KCOV_INSTRUMENT			:= n
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| 
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| lib-y				:= efi-stub-helper.o gop.o secureboot.o tpm.o \
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| 				   file.o mem.o random.o randomalloc.o pci.o \
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| 				   skip_spaces.o lib-cmdline.o lib-ctype.o \
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| 				   alignedmem.o relocate.o vsprintf.o
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| 
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| # include the stub's libfdt dependencies from lib/ when needed
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| libfdt-deps			:= fdt_rw.c fdt_ro.c fdt_wip.c fdt.c \
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| 				   fdt_empty_tree.c fdt_sw.c
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| 
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| lib-$(CONFIG_EFI_PARAMS_FROM_FDT) += fdt.o \
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| 				     $(patsubst %.c,lib-%.o,$(libfdt-deps))
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| 
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| $(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
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| 	$(call if_changed_rule,cc_o_c)
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| 
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| lib-$(CONFIG_EFI_GENERIC_STUB)	+= efi-stub.o string.o intrinsics.o systable.o
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| 
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| lib-$(CONFIG_ARM)		+= arm32-stub.o
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| lib-$(CONFIG_ARM64)		+= arm64-stub.o smbios.o
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| lib-$(CONFIG_X86)		+= x86-stub.o
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| lib-$(CONFIG_X86_64)		+= x86-5lvl.o
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| lib-$(CONFIG_RISCV)		+= riscv-stub.o
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| lib-$(CONFIG_LOONGARCH)		+= loongarch-stub.o
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| 
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| CFLAGS_arm32-stub.o		:= -DTEXT_OFFSET=$(TEXT_OFFSET)
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| 
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| zboot-obj-$(CONFIG_RISCV)	:= lib-clz_ctz.o lib-ashldi3.o
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| lib-$(CONFIG_EFI_ZBOOT)		+= zboot.o $(zboot-obj-y)
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| 
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| extra-y				:= $(lib-y)
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| lib-y				:= $(patsubst %.o,%.stub.o,$(lib-y))
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| 
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| # Even when -mbranch-protection=none is set, Clang will generate a
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| # .note.gnu.property for code-less object files (like lib/ctype.c),
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| # so work around this by explicitly removing the unwanted section.
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| # https://bugs.llvm.org/show_bug.cgi?id=46480
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| STUBCOPY_FLAGS-y		+= --remove-section=.note.gnu.property
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| 
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| STUBCOPY_RELOC-$(CONFIG_X86_32)	:= R_386_32
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| STUBCOPY_RELOC-$(CONFIG_X86_64)	:= R_X86_64_64
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| 
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| #
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| # ARM discards the .data section because it disallows r/w data in the
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| # decompressor. So move our .data to .data.efistub and .bss to .bss.efistub,
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| # which are preserved explicitly by the decompressor linker script.
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| #
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| STUBCOPY_FLAGS-$(CONFIG_ARM)	+= --rename-section .data=.data.efistub	\
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| 				   --rename-section .bss=.bss.efistub,load,alloc
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| STUBCOPY_RELOC-$(CONFIG_ARM)	:= R_ARM_ABS
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| 
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| #
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| # arm64 puts the stub in the kernel proper, which will unnecessarily retain all
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| # code indefinitely unless it is annotated as __init/__initdata/__initconst etc.
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| # So let's apply the __init annotations at the section level, by prefixing
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| # the section names directly. This will ensure that even all the inline string
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| # literals are covered.
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| # The fact that the stub and the kernel proper are essentially the same binary
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| # also means that we need to be extra careful to make sure that the stub does
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| # not rely on any absolute symbol references, considering that the virtual
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| # kernel mapping that the linker uses is not active yet when the stub is
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| # executing. So build all C dependencies of the EFI stub into libstub, and do
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| # a verification pass to see if any absolute relocations exist in any of the
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| # object files.
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| #
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| STUBCOPY_FLAGS-$(CONFIG_ARM64)	+= --prefix-alloc-sections=.init \
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| 				   --prefix-symbols=__efistub_
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| STUBCOPY_RELOC-$(CONFIG_ARM64)	:= R_AARCH64_ABS
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| 
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| # For RISC-V, we don't need anything special other than arm64. Keep all the
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| # symbols in .init section and make sure that no absolute symbols references
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| # doesn't exist.
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| STUBCOPY_FLAGS-$(CONFIG_RISCV)	+= --prefix-alloc-sections=.init \
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| 				   --prefix-symbols=__efistub_
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| STUBCOPY_RELOC-$(CONFIG_RISCV)	:= R_RISCV_HI20
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| 
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| # For LoongArch, keep all the symbols in .init section and make sure that no
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| # absolute symbols references exist.
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| STUBCOPY_FLAGS-$(CONFIG_LOONGARCH)	+= --prefix-alloc-sections=.init \
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| 					   --prefix-symbols=__efistub_
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| STUBCOPY_RELOC-$(CONFIG_LOONGARCH)	:= R_LARCH_MARK_LA
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| 
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| $(obj)/%.stub.o: $(obj)/%.o FORCE
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| 	$(call if_changed,stubcopy)
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| 
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| #
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| # Strip debug sections and some other sections that may legally contain
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| # absolute relocations, so that we can inspect the remaining sections for
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| # such relocations. If none are found, regenerate the output object, but
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| # this time, use objcopy and leave all sections in place.
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| #
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| quiet_cmd_stubcopy = STUBCPY $@
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|       cmd_stubcopy =							\
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| 	$(STRIP) --strip-debug -o $@ $<;				\
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| 	if $(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y); then		\
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| 		echo "$@: absolute symbol references not allowed in the EFI stub" >&2; \
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| 		/bin/false;						\
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| 	fi;								\
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| 	$(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@
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