On Wed, 3 Jun 2020 at 07:34, Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote: > > 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. > Why? > 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. > The code works perfectly fine as is, and I don't see what is fundamentally wrong with using static libraries outside of lib/ and arch/*/lib. Also, I would like this code to still be incorporated as a static library into arm64 as well, so that only pieces that are actually needed are incorporated into the final image. > 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 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
