On Fri, Jun 26, 2020 at 11:59 AM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
>
> Some Makefiles already pass -ffreestanding unconditionally.
> For example, arch/arm64/lib/Makefile, arch/x86/purgatory/Makefile.
> No problem report so far about hard-coding this option. So, we can
> assume all supported compilers know -ffreestanding.
>
> I confirmed GCC 4.8 and Clang manuals document this option.
>
> Get rid of cc-option from -ffreestanding.
>
> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> ---
>
> arch/s390/Makefile | 2 +-
> arch/x86/Makefile | 2 +-
> arch/x86/boot/compressed/Makefile | 2 +-
> drivers/firmware/efi/libstub/Makefile | 2 +-
> 4 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/s390/Makefile b/arch/s390/Makefile
> index 8dfa2cf1f05c..ba94b03c8b2f 100644
> --- a/arch/s390/Makefile
> +++ b/arch/s390/Makefile
> @@ -27,7 +27,7 @@ KBUILD_CFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -O2
> KBUILD_CFLAGS_DECOMPRESSOR += -DDISABLE_BRANCH_PROFILING -D__NO_FORTIFY
> KBUILD_CFLAGS_DECOMPRESSOR += -fno-delete-null-pointer-checks -msoft-float
> KBUILD_CFLAGS_DECOMPRESSOR += -fno-asynchronous-unwind-tables
> -KBUILD_CFLAGS_DECOMPRESSOR += $(call cc-option,-ffreestanding)
> +KBUILD_CFLAGS_DECOMPRESSOR += -ffreestanding
> KBUILD_CFLAGS_DECOMPRESSOR += $(call cc-disable-warning, address-of-packed-member)
> KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),-g)
> KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO_DWARF4), $(call cc-option, -gdwarf-4,))
> diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> index 89c3cdfba753..edc68538a04e 100644
> --- a/arch/x86/Makefile
> +++ b/arch/x86/Makefile
> @@ -36,7 +36,7 @@ REALMODE_CFLAGS := $(M16_CFLAGS) -g -Os -DDISABLE_BRANCH_PROFILING \
> -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
> -mno-mmx -mno-sse
>
> -REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -ffreestanding)
> +REALMODE_CFLAGS += -ffreestanding
See also
commit 032a2c4f65a2 ("x86/build: Use __cc-option for boot code
compiler options")
for additional context (to fellow reviewers).
> REALMODE_CFLAGS += -fno-stack-protector
> REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member)
> REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4))
> diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
> index c88a31569a5e..b7beabecef8a 100644
> --- a/arch/x86/boot/compressed/Makefile
> +++ b/arch/x86/boot/compressed/Makefile
> @@ -35,7 +35,7 @@ cflags-$(CONFIG_X86_32) := -march=i386
> cflags-$(CONFIG_X86_64) := -mcmodel=small
> KBUILD_CFLAGS += $(cflags-y)
> KBUILD_CFLAGS += -mno-mmx -mno-sse
> -KBUILD_CFLAGS += $(call cc-option,-ffreestanding)
> +KBUILD_CFLAGS += -ffreestanding
> KBUILD_CFLAGS += -fno-stack-protector
> KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member)
> KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
> diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
> index f8418763cd79..296b18fbd7a2 100644
> --- a/drivers/firmware/efi/libstub/Makefile
> +++ b/drivers/firmware/efi/libstub/Makefile
> @@ -28,7 +28,7 @@ cflags-$(CONFIG_EFI_GENERIC_STUB) += -I$(srctree)/scripts/dtc/libfdt
> KBUILD_CFLAGS := $(cflags-y) -Os -DDISABLE_BRANCH_PROFILING \
> -include $(srctree)/drivers/firmware/efi/libstub/hidden.h \
> -D__NO_FORTIFY \
> - $(call cc-option,-ffreestanding) \
> + -ffreestanding \
> -fno-stack-protector \
> $(call cc-option,-fno-addrsig) \
> -D__DISABLE_EXPORTS
> --
--
Thanks,
~Nick Desaulniers
