Introduce CC_FLAGS_DIALECT to make it easier to update the various places in the tree that rely on the GNU C standard and Microsoft extensions flags atomically. All remaining uses of '-std=gnu11' and '-fms-extensions' are in the tools directory (which has its own build system) and other standalone Makefiles. This will allow the kernel to use a narrower option to enable the Microsoft anonymous tagged structure extension in a simpler manner. Place the CC_FLAGS_DIALECT block after the configuration include (so that a future change can move the selection of the flag to Kconfig) but before the arch/$(SRCARCH)/Makefile include (so that CC_FLAGS_DIALECT is available for use in those Makefiles).
Signed-off-by: Nathan Chancellor <[email protected]> --- Makefile | 16 ++++++++++++---- arch/arm64/kernel/vdso32/Makefile | 3 +-- arch/loongarch/vdso/Makefile | 2 +- arch/parisc/boot/compressed/Makefile | 2 +- arch/powerpc/boot/Makefile | 3 +-- arch/s390/Makefile | 3 +-- arch/s390/purgatory/Makefile | 3 +-- arch/x86/Makefile | 6 +----- arch/x86/boot/compressed/Makefile | 6 +----- drivers/firmware/efi/libstub/Makefile | 3 +-- scripts/Makefile.warn | 5 ----- 11 files changed, 21 insertions(+), 31 deletions(-) diff --git a/Makefile b/Makefile index e944c6e71e81..06ff3032a6bc 100644 --- a/Makefile +++ b/Makefile @@ -587,7 +587,6 @@ LINUXINCLUDE := \ KBUILD_AFLAGS := -D__ASSEMBLY__ -fno-PIE KBUILD_CFLAGS := -KBUILD_CFLAGS += -std=gnu11 KBUILD_CFLAGS += -fshort-wchar KBUILD_CFLAGS += -funsigned-char KBUILD_CFLAGS += -fno-common @@ -790,6 +789,18 @@ ifdef need-config include $(objtree)/include/config/auto.conf endif +CC_FLAGS_DIALECT := -std=gnu11 +# Allow including a tagged struct or union anonymously in another struct/union. +CC_FLAGS_DIALECT += -fms-extensions +# Clang enables warnings about GNU and Microsoft extensions by default, disable +# them because this is expected with the above options. +ifdef CONFIG_CC_IS_CLANG +CC_FLAGS_DIALECT += -Wno-gnu +CC_FLAGS_DIALECT += -Wno-microsoft-anon-tag +endif +export CC_FLAGS_DIALECT +KBUILD_CFLAGS += $(CC_FLAGS_DIALECT) + ifeq ($(KBUILD_EXTMOD),) # Objects we will link into vmlinux / subdirs we need to visit core-y := @@ -1093,9 +1104,6 @@ NOSTDINC_FLAGS += -nostdinc # perform bounds checking. KBUILD_CFLAGS += $(call cc-option, -fstrict-flex-arrays=3) -# Allow including a tagged struct or union anonymously in another struct/union. -KBUILD_CFLAGS += -fms-extensions - # disable invalid "can't wrap" optimizations for signed / pointers KBUILD_CFLAGS += -fno-strict-overflow diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile index 9d0efed91414..bea3675fa668 100644 --- a/arch/arm64/kernel/vdso32/Makefile +++ b/arch/arm64/kernel/vdso32/Makefile @@ -63,7 +63,7 @@ VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ $(filter -Werror,$(KBUILD_CPPFLAGS)) \ -Werror-implicit-function-declaration \ -Wno-format-security \ - -std=gnu11 -fms-extensions + $(CC_FLAGS_DIALECT) VDSO_CFLAGS += -O2 # Some useful compiler-dependent flags from top-level Makefile VDSO_CFLAGS += $(call cc32-option,-Wno-pointer-sign) @@ -71,7 +71,6 @@ VDSO_CFLAGS += -fno-strict-overflow VDSO_CFLAGS += $(call cc32-option,-Werror=strict-prototypes) VDSO_CFLAGS += -Werror=date-time VDSO_CFLAGS += $(call cc32-option,-Werror=incompatible-pointer-types) -VDSO_CFLAGS += $(if $(CONFIG_CC_IS_CLANG),-Wno-microsoft-anon-tag) # Compile as THUMB2 or ARM. Unwinding via frame-pointers in THUMB2 is # unreliable. diff --git a/arch/loongarch/vdso/Makefile b/arch/loongarch/vdso/Makefile index 520f1513f07d..904ef4a0d826 100644 --- a/arch/loongarch/vdso/Makefile +++ b/arch/loongarch/vdso/Makefile @@ -24,7 +24,7 @@ endif cflags-vdso := $(ccflags-vdso) \ -isystem $(shell $(CC) -print-file-name=include) \ $(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \ - -std=gnu11 -fms-extensions -O2 -g -fno-strict-aliasing -fno-common -fno-builtin \ + $(CC_FLAGS_DIALECT) -O2 -g -fno-strict-aliasing -fno-common -fno-builtin \ -fno-stack-protector -fno-jump-tables -DDISABLE_BRANCH_PROFILING \ $(call cc-option, -fno-asynchronous-unwind-tables) \ $(call cc-option, -fno-stack-protector) diff --git a/arch/parisc/boot/compressed/Makefile b/arch/parisc/boot/compressed/Makefile index f8481e4e9d21..14eefb5ed5d1 100644 --- a/arch/parisc/boot/compressed/Makefile +++ b/arch/parisc/boot/compressed/Makefile @@ -18,7 +18,7 @@ KBUILD_CFLAGS += -fno-PIE -mno-space-regs -mdisable-fpregs -Os ifndef CONFIG_64BIT KBUILD_CFLAGS += -mfast-indirect-calls endif -KBUILD_CFLAGS += -std=gnu11 -fms-extensions +KBUILD_CFLAGS += $(CC_FLAGS_DIALECT) LDFLAGS_vmlinux := -X -e startup --as-needed -T $(obj)/vmlinux: $(obj)/vmlinux.lds $(addprefix $(obj)/, $(OBJECTS)) $(LIBGCC) FORCE diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile index f1a4761ebd44..7ee0fa2d3371 100644 --- a/arch/powerpc/boot/Makefile +++ b/arch/powerpc/boot/Makefile @@ -70,7 +70,7 @@ BOOTCPPFLAGS := -nostdinc $(LINUXINCLUDE) BOOTCPPFLAGS += -isystem $(shell $(BOOTCC) -print-file-name=include) BOOTCFLAGS := $(BOOTTARGETFLAGS) \ - -std=gnu11 -fms-extensions \ + $(CC_FLAGS_DIALECT) \ -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ -fno-strict-aliasing -O2 \ -msoft-float -mno-altivec -mno-vsx \ @@ -86,7 +86,6 @@ BOOTARFLAGS := -crD ifdef CONFIG_CC_IS_CLANG BOOTCFLAGS += $(CLANG_FLAGS) -BOOTCFLAGS += -Wno-microsoft-anon-tag BOOTAFLAGS += $(CLANG_FLAGS) endif diff --git a/arch/s390/Makefile b/arch/s390/Makefile index d78ad6885ca2..c8d16aca1cdc 100644 --- a/arch/s390/Makefile +++ b/arch/s390/Makefile @@ -22,7 +22,7 @@ KBUILD_AFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -D__ASSEMBLY__ ifndef CONFIG_AS_IS_LLVM KBUILD_AFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),$(aflags_dwarf)) endif -KBUILD_CFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -O2 -mpacked-stack -std=gnu11 -fms-extensions +KBUILD_CFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -O2 -mpacked-stack $(CC_FLAGS_DIALECT) KBUILD_CFLAGS_DECOMPRESSOR += -DDISABLE_BRANCH_PROFILING -D__NO_FORTIFY KBUILD_CFLAGS_DECOMPRESSOR += -D__DECOMPRESSOR KBUILD_CFLAGS_DECOMPRESSOR += -Wno-pointer-sign @@ -35,7 +35,6 @@ KBUILD_CFLAGS_DECOMPRESSOR += $(call cc-disable-warning, address-of-packed-membe KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),-g) KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO_DWARF4), $(call cc-option, -gdwarf-4,)) KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_CC_NO_ARRAY_BOUNDS),-Wno-array-bounds) -KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_CC_IS_CLANG),-Wno-microsoft-anon-tag) UTS_MACHINE := s390x STACK_SIZE := $(if $(CONFIG_KASAN),65536,$(if $(CONFIG_KMSAN),65536,16384)) diff --git a/arch/s390/purgatory/Makefile b/arch/s390/purgatory/Makefile index 61d240a37633..95a8ac45b67e 100644 --- a/arch/s390/purgatory/Makefile +++ b/arch/s390/purgatory/Makefile @@ -13,7 +13,7 @@ CFLAGS_sha256.o := -D__NO_FORTIFY $(obj)/mem.o: $(srctree)/arch/s390/lib/mem.S FORCE $(call if_changed_rule,as_o_S) -KBUILD_CFLAGS := -std=gnu11 -fms-extensions -fno-strict-aliasing -Wall -Wstrict-prototypes +KBUILD_CFLAGS := $(CC_FLAGS_DIALECT) -fno-strict-aliasing -Wall -Wstrict-prototypes KBUILD_CFLAGS += -Wno-pointer-sign -Wno-sign-compare KBUILD_CFLAGS += -fno-zero-initialized-in-bss -fno-builtin -ffreestanding KBUILD_CFLAGS += -Os -m64 -msoft-float -fno-common @@ -21,7 +21,6 @@ KBUILD_CFLAGS += -fno-stack-protector KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING KBUILD_CFLAGS += -D__DISABLE_EXPORTS KBUILD_CFLAGS += $(CLANG_FLAGS) -KBUILD_CFLAGS += $(if $(CONFIG_CC_IS_CLANG),-Wno-microsoft-anon-tag) KBUILD_CFLAGS += $(call cc-option,-fno-PIE) KBUILD_CFLAGS += $(call cc-option, -Wno-default-const-init-unsafe) KBUILD_AFLAGS := $(filter-out -DCC_USING_EXPOLINE,$(KBUILD_AFLAGS)) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 5f881460a8b5..46fec0b08487 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -48,7 +48,7 @@ endif # How to compile the 16-bit code. Note we always compile for -march=i386; # that way we can complain to the user if the CPU is insufficient. -REALMODE_CFLAGS := -std=gnu11 -fms-extensions -m16 -g -Os \ +REALMODE_CFLAGS := $(CC_FLAGS_DIALECT) -m16 -g -Os \ -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \ -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \ -fno-strict-aliasing -fomit-frame-pointer -fno-pic \ @@ -59,10 +59,6 @@ REALMODE_CFLAGS += -fno-stack-protector REALMODE_CFLAGS += -Wno-address-of-packed-member REALMODE_CFLAGS += $(cc_stack_align4) REALMODE_CFLAGS += $(CLANG_FLAGS) -ifdef CONFIG_CC_IS_CLANG -REALMODE_CFLAGS += -Wno-gnu -REALMODE_CFLAGS += -Wno-microsoft-anon-tag -endif export REALMODE_CFLAGS # BITS is used as extension for files which are available in a 32 bit diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 68f9d7a1683b..8924196927bf 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -25,7 +25,7 @@ targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \ # avoid errors with '-march=i386', and future flags may depend on the target to # be valid. KBUILD_CFLAGS := -m$(BITS) -O2 $(CLANG_FLAGS) -KBUILD_CFLAGS += -std=gnu11 -fms-extensions +KBUILD_CFLAGS += $(CC_FLAGS_DIALECT) KBUILD_CFLAGS += -fno-strict-aliasing -fPIE KBUILD_CFLAGS += -Wundef KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING @@ -36,10 +36,6 @@ KBUILD_CFLAGS += -mno-mmx -mno-sse KBUILD_CFLAGS += -ffreestanding -fshort-wchar KBUILD_CFLAGS += -fno-stack-protector KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) -ifdef CONFIG_CC_IS_CLANG -KBUILD_CFLAGS += -Wno-gnu -KBUILD_CFLAGS += -Wno-microsoft-anon-tag -endif KBUILD_CFLAGS += -Wno-pointer-sign KBUILD_CFLAGS += -fno-asynchronous-unwind-tables KBUILD_CFLAGS += -D__DISABLE_EXPORTS diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index e386ffd009b7..fbb8d4e33256 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -11,12 +11,11 @@ cflags-y := $(KBUILD_CFLAGS) cflags-$(CONFIG_X86_32) := -march=i386 cflags-$(CONFIG_X86_64) := -mcmodel=small -cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ -std=gnu11 -fms-extensions \ +cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ $(CC_FLAGS_DIALECT) \ -fPIC -fno-strict-aliasing -mno-red-zone \ -mno-mmx -mno-sse -fshort-wchar \ -Wno-pointer-sign \ $(call cc-disable-warning, address-of-packed-member) \ - $(if $(CONFIG_CC_IS_CLANG),-Wno-gnu -Wno-microsoft-anon-tag) \ -fno-asynchronous-unwind-tables \ $(CLANG_FLAGS) diff --git a/scripts/Makefile.warn b/scripts/Makefile.warn index 5567da6c7dfe..e77ca875aea4 100644 --- a/scripts/Makefile.warn +++ b/scripts/Makefile.warn @@ -28,11 +28,6 @@ endif KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds ifdef CONFIG_CC_IS_CLANG -# The kernel builds with '-std=gnu11' and '-fms-extensions' so use of GNU and -# Microsoft extensions is acceptable. -KBUILD_CFLAGS += -Wno-gnu -KBUILD_CFLAGS += -Wno-microsoft-anon-tag - # Clang checks for overflow/truncation with '%p', while GCC does not: # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111219 KBUILD_CFLAGS += $(call cc-option, -Wno-format-overflow-non-kprintf) -- 2.53.0
