# # The stub may be linked into the kernel proper or into a separate boot binary, # but in either case, it executes before the kernel does (with MMU disabled) so # things like ftrace and stack-protector are likely to cause trouble if left # enabled, even if doing so doesn't break the build. # cflags-$([31mCONFIG_X86_32[0m) := -march=i386 cflags-$([31mCONFIG_X86_64[0m) := -mcmodel=small cflags-$([31mCONFIG_X86[0m) += -m$(BITS) -D__KERNEL__ -O2 \ -fPIC -fno-strict-aliasing -mno-red-zone \ -mno-mmx -mno-sse cflags-$([31mCONFIG_ARM64[0m) := $(subst -pg,,$(KBUILD_CFLAGS)) cflags-$([31mCONFIG_ARM[0m) := $(subst -pg,,$(KBUILD_CFLAGS)) -g0 \ -fno-builtin -fpic -mno-single-pic-base cflags-$([31mCONFIG_EFI_ARMSTUB[0m) += -I$(srctree)/scripts/dtc/libfdt KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \ $(call cc-option,-ffreestanding) \ $(call cc-option,-fno-stack-protector) GCOV_PROFILE := n KASAN_SANITIZE := n UBSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. KCOV_INSTRUMENT := n lib-y := efi-stub-helper.o gop.o # include the stub's generic dependencies from lib/ when building for ARM/arm64 arm-deps := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c sort.c $(obj)/lib-%.o: $(srctree)/lib/%.c FORCE $(call if_changed_rule,cc_o_c) lib-$([31mCONFIG_EFI_ARMSTUB[0m) += arm-stub.o fdt.o string.o random.o \ $(patsubst %.c,lib-%.o,$(arm-deps)) lib-$([31mCONFIG_ARM[0m) += arm32-stub.o lib-$([31mCONFIG_ARM64[0m) += arm64-stub.o CFLAGS_arm64-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET) # # arm64 puts the stub in the kernel proper, which will unnecessarily retain all # code indefinitely unless it is annotated as __init/__initdata/__initconst etc. # So let's apply the __init annotations at the section level, by prefixing # the section names directly. This will ensure that even all the inline string # literals are covered. # The fact that the stub and the kernel proper are essentially the same binary # also means that we need to be extra careful to make sure that the stub does # not rely on any absolute symbol references, considering that the virtual # kernel mapping that the linker uses is not active yet when the stub is # executing. So build all C dependencies of the EFI stub into libstub, and do # a verification pass to see if any absolute relocations exist in any of the # object files. # extra-$([31mCONFIG_EFI_ARMSTUB[0m) := $(lib-y) lib-$([31mCONFIG_EFI_ARMSTUB[0m) := $(patsubst %.o,%.stub.o,$(lib-y)) STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab* -R *kcrctab* STUBCOPY_FLAGS-$([31mCONFIG_ARM64[0m) += --prefix-alloc-sections=.init \ --prefix-symbols=__efistub_ STUBCOPY_RELOC-$([31mCONFIG_ARM64[0m) := R_AARCH64_ABS $(obj)/%.stub.o: $(obj)/%.o FORCE $(call if_changed,stubcopy) quiet_cmd_stubcopy = STUBCPY $@ cmd_stubcopy = if $(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@; then \ $(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y) \ && (echo >&2 "$@: absolute symbol references not allowed in the EFI stub"; \ rm -f $@; /bin/false); else /bin/false; fi # # ARM discards the .data section because it disallows r/w data in the # decompressor. So move our .data to .data.efistub, which is preserved # explicitly by the decompressor linker script. # STUBCOPY_FLAGS-$([31mCONFIG_ARM[0m) += --rename-section .data=.data.efistub \ -R ___ksymtab+sort -R ___kcrctab+sort STUBCOPY_RELOC-$([31mCONFIG_ARM[0m) := R_ARM_ABS |