Documentation/kbuild/makefiles.rst says: Use of lib-y is normally restricted to `lib/` and `arch/*/lib`. I want to disallow lib-y outside of them. Add a custom rule to build lib.a, which is linked to the decompressor for ARCH=x86, ARCH=arm. For ARCH=arm64, use obj-y to link objects to vmlinux in the ordinary way. Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> --- arch/arm64/Makefile | 1 - drivers/firmware/efi/Makefile | 2 +- drivers/firmware/efi/libstub/Makefile | 51 +++++++++++++++------------ 3 files changed, 30 insertions(+), 24 deletions(-) diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 650e1185c190..ab79b20efc8d 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -145,7 +145,6 @@ export TEXT_OFFSET core-y += arch/arm64/ libs-y := arch/arm64/lib/ $(libs-y) -core-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a # Default target when executing plain make boot := arch/arm64/boot diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile index 7a216984552b..317a05cd388b 100644 --- a/drivers/firmware/efi/Makefile +++ b/drivers/firmware/efi/Makefile @@ -20,7 +20,7 @@ obj-$(CONFIG_EFI_VARS_PSTORE) += efi-pstore.o obj-$(CONFIG_UEFI_CPER) += cper.o obj-$(CONFIG_EFI_RUNTIME_MAP) += runtime-map.o obj-$(CONFIG_EFI_RUNTIME_WRAPPERS) += runtime-wrappers.o -subdir-$(CONFIG_EFI_STUB) += libstub +obj-$(CONFIG_EFI_STUB) += libstub/ obj-$(CONFIG_EFI_FAKE_MEMMAP) += fake_map.o obj-$(CONFIG_EFI_BOOTLOADER_CONTROL) += efibc.o obj-$(CONFIG_EFI_TEST) += test/ diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index cce4a7436052..e4e9b17fa3b2 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -44,7 +44,7 @@ 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 secureboot.o tpm.o \ +stub-obj-y := efi-stub-helper.o gop.o secureboot.o tpm.o \ file.o mem.o random.o randomalloc.o pci.o \ skip_spaces.o lib-cmdline.o lib-ctype.o \ alignedmem.o relocate.o vsprintf.o @@ -55,15 +55,19 @@ efi-deps-y := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c $(obj)/lib-%.o: $(srctree)/lib/%.c FORCE $(call if_changed_rule,cc_o_c) -lib-$(CONFIG_EFI_GENERIC_STUB) += efi-stub.o fdt.o string.o \ +stub-obj-$(CONFIG_EFI_GENERIC_STUB) += efi-stub.o fdt.o string.o \ $(patsubst %.c,lib-%.o,$(efi-deps-y)) -lib-$(CONFIG_ARM) += arm32-stub.o -lib-$(CONFIG_ARM64) += arm64-stub.o -lib-$(CONFIG_X86) += x86-stub.o +stub-obj-$(CONFIG_ARM) += arm32-stub.o +stub-obj-$(CONFIG_ARM64) += arm64-stub.o +stub-obj-$(CONFIG_X86) += x86-stub.o CFLAGS_arm32-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET) CFLAGS_arm64-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET) +targets += $(stub-obj-y) +stub-obj-y := $(patsubst %.o,%.stub.o, $(stub-obj-y)) +targets += $(stub-obj-y) + # # For x86, bootloaders like systemd-boot or grub-efi do not zero-initialize the # .bss section, so the .bss section of the EFI stub needs to be included in the @@ -83,23 +87,6 @@ STUBCOPY_FLAGS-$(CONFIG_ARM) += --rename-section .data=.data.efistub \ --rename-section .bss=.bss.efistub,load,alloc STUBCOPY_RELOC-$(CONFIG_ARM) := R_ARM_ABS -# -# 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-y := $(lib-y) -lib-y := $(patsubst %.o,%.stub.o,$(lib-y)) - STUBCOPY_FLAGS-$(CONFIG_ARM64) += --prefix-alloc-sections=.init \ --prefix-symbols=__efistub_ STUBCOPY_RELOC-$(CONFIG_ARM64) := R_AARCH64_ABS @@ -121,3 +108,23 @@ quiet_cmd_stubcopy = STUBCPY $@ /bin/false; \ fi; \ $(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@ + +# arm64 puts the stub in the kernel proper, which will unnecessarily retain all +# code indefinitely unless it is annotated as __init/__initdata/__initconst etc. +# So let's apply the __init annotations at the section level, by prefixing +# the section names directly. This will ensure that even all the inline string +# literals are covered. +# The fact that the stub and the kernel proper are essentially the same binary +# also means that we need to be extra careful to make sure that the stub does +# not rely on any absolute symbol references, considering that the virtual +# kernel mapping that the linker uses is not active yet when the stub is +# executing. So build all C dependencies of the EFI stub into libstub, and do +# a verification pass to see if any absolute relocations exist in any of the +# object files. +# +obj-$(CONFIG_ARM64) += $(stub-obj-y) +extra-$(CONFIG_ARM) += lib.a +extra-$(CONFIG_X86) += lib.a + +$(obj)/lib.a: $(addprefix $(obj)/, $(stub-obj-y)) FORCE + $(call if_changed,ar) -- 2.25.1
