diff options
Diffstat (limited to 'kernel/drivers/firmware/efi/libstub/Makefile')
| -rw-r--r-- | kernel/drivers/firmware/efi/libstub/Makefile | 42 |
1 files changed, 35 insertions, 7 deletions
diff --git a/kernel/drivers/firmware/efi/libstub/Makefile b/kernel/drivers/firmware/efi/libstub/Makefile index 280bc0a63..3c0467d36 100644 --- a/kernel/drivers/firmware/efi/libstub/Makefile +++ b/kernel/drivers/firmware/efi/libstub/Makefile @@ -14,6 +14,8 @@ cflags-$(CONFIG_ARM64) := $(subst -pg,,$(KBUILD_CFLAGS)) cflags-$(CONFIG_ARM) := $(subst -pg,,$(KBUILD_CFLAGS)) \ -fno-builtin -fpic -mno-single-pic-base +cflags-$(CONFIG_EFI_ARMSTUB) += -I$(srctree)/scripts/dtc/libfdt + KBUILD_CFLAGS := $(cflags-y) \ $(call cc-option,-ffreestanding) \ $(call cc-option,-fno-stack-protector) @@ -22,9 +24,18 @@ GCOV_PROFILE := n KASAN_SANITIZE := n lib-y := efi-stub-helper.o -lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o -CFLAGS_fdt.o += -I$(srctree)/scripts/dtc/libfdt/ +# include the stub's generic dependencies from lib/ when building for ARM/arm64 +arm-deps := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c sort.c + +$(obj)/lib-%.o: $(srctree)/lib/%.c FORCE + $(call if_changed_rule,cc_o_c) + +lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o \ + $(patsubst %.c,lib-%.o,$(arm-deps)) + +lib-$(CONFIG_ARM64) += arm64-stub.o +CFLAGS_arm64-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET) # # arm64 puts the stub in the kernel proper, which will unnecessarily retain all @@ -32,10 +43,27 @@ CFLAGS_fdt.o += -I$(srctree)/scripts/dtc/libfdt/ # So let's apply the __init annotations at the section level, by prefixing # the section names directly. This will ensure that even all the inline string # literals are covered. +# The fact that the stub and the kernel proper are essentially the same binary +# also means that we need to be extra careful to make sure that the stub does +# not rely on any absolute symbol references, considering that the virtual +# kernel mapping that the linker uses is not active yet when the stub is +# executing. So build all C dependencies of the EFI stub into libstub, and do +# a verification pass to see if any absolute relocations exist in any of the +# object files. # -extra-$(CONFIG_ARM64) := $(lib-y) -lib-$(CONFIG_ARM64) := $(patsubst %.o,%.init.o,$(lib-y)) +extra-$(CONFIG_EFI_ARMSTUB) := $(lib-y) +lib-$(CONFIG_EFI_ARMSTUB) := $(patsubst %.o,%.stub.o,$(lib-y)) + +STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab* -R *kcrctab* +STUBCOPY_FLAGS-$(CONFIG_ARM64) += --prefix-alloc-sections=.init \ + --prefix-symbols=__efistub_ +STUBCOPY_RELOC-$(CONFIG_ARM64) := R_AARCH64_ABS + +$(obj)/%.stub.o: $(obj)/%.o FORCE + $(call if_changed,stubcopy) -OBJCOPYFLAGS := --prefix-alloc-sections=.init -$(obj)/%.init.o: $(obj)/%.o FORCE - $(call if_changed,objcopy) +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 |