From: Nathan Chancellor Date: Fri, 31 Oct 2025 01:26:28 +0000 (-0400) Subject: kbuild: Add '-fms-extensions' to areas with dedicated CFLAGS X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=5ff8ad3909524ad55297a434f87c238224825bf4;p=thirdparty%2Flinux.git kbuild: Add '-fms-extensions' to areas with dedicated CFLAGS This is a follow up to commit c4781dc3d1cf ("Kbuild: enable -fms-extensions") but in a separate change due to being substantially different from the initial submission. There are many places within the kernel that use their own CFLAGS instead of the main KBUILD_CFLAGS, meaning code written with the main kernel's use of '-fms-extensions' in mind that may be tangentially included in these areas will result in "error: declaration does not declare anything" messages from the compiler. Add '-fms-extensions' to all these areas to ensure consistency, along with -Wno-microsoft-anon-tag to silence clang's warning about use of the extension that the kernel cares about using. parisc does not build with clang so it does not need this warning flag. LoongArch does not need it either because -W flags from KBUILD_FLAGS are pulled into cflags-vdso. Reported-by: Christian Brauner Closes: https://lore.kernel.org/20251030-meerjungfrau-getrocknet-7b46eacc215d@brauner/ Reviewed-by: Christian Brauner Acked-by: Ard Biesheuvel Signed-off-by: Nathan Chancellor --- diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile index ffa3536581f67..9d0efed91414c 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 + -std=gnu11 -fms-extensions VDSO_CFLAGS += -O2 # Some useful compiler-dependent flags from top-level Makefile VDSO_CFLAGS += $(call cc32-option,-Wno-pointer-sign) @@ -71,6 +71,7 @@ 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 d8316f9934824..c0cc3ca5da9f4 100644 --- a/arch/loongarch/vdso/Makefile +++ b/arch/loongarch/vdso/Makefile @@ -19,7 +19,7 @@ ccflags-vdso := \ cflags-vdso := $(ccflags-vdso) \ -isystem $(shell $(CC) -print-file-name=include) \ $(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \ - -std=gnu11 -O2 -g -fno-strict-aliasing -fno-common -fno-builtin \ + -std=gnu11 -fms-extensions -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 17c42d718eb33..f8481e4e9d214 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 +KBUILD_CFLAGS += -std=gnu11 -fms-extensions 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 c47b78c1d3e7e..f1a4761ebd44b 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 \ + -std=gnu11 -fms-extensions \ -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ -fno-strict-aliasing -O2 \ -msoft-float -mno-altivec -mno-vsx \ @@ -86,6 +86,7 @@ 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 b4769241332bb..8578361133a4b 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 +KBUILD_CFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -O2 -mpacked-stack -std=gnu11 -fms-extensions KBUILD_CFLAGS_DECOMPRESSOR += -DDISABLE_BRANCH_PROFILING -D__NO_FORTIFY KBUILD_CFLAGS_DECOMPRESSOR += -D__DECOMPRESSOR KBUILD_CFLAGS_DECOMPRESSOR += -Wno-pointer-sign @@ -35,6 +35,7 @@ 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 bd39b36e7bd68..0c196a5b194af 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 -fno-strict-aliasing -Wall -Wstrict-prototypes +KBUILD_CFLAGS := -std=gnu11 -fms-extensions -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 @@ -21,6 +21,7 @@ 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_AFLAGS := $(filter-out -DCC_USING_EXPOLINE,$(KBUILD_AFLAGS)) KBUILD_AFLAGS += -D__DISABLE_EXPORTS diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 4db7e4bf69f5c..e20e25b8b16ce 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -48,7 +48,8 @@ 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 -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \ +REALMODE_CFLAGS := -std=gnu11 -fms-extensions -m16 -g -Os \ + -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \ -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \ -fno-strict-aliasing -fomit-frame-pointer -fno-pic \ -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none) @@ -60,6 +61,7 @@ REALMODE_CFLAGS += $(cc_stack_align4) REALMODE_CFLAGS += $(CLANG_FLAGS) ifdef CONFIG_CC_IS_CLANG REALMODE_CFLAGS += -Wno-gnu +REALMODE_CFLAGS += -Wno-microsoft-anon-tag endif export REALMODE_CFLAGS diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 74657589264df..68f9d7a1683b5 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -25,7 +25,7 @@ targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \ # avoid errors with '-march=i386', and future flags may depend on the target to # be valid. KBUILD_CFLAGS := -m$(BITS) -O2 $(CLANG_FLAGS) -KBUILD_CFLAGS += -std=gnu11 +KBUILD_CFLAGS += -std=gnu11 -fms-extensions KBUILD_CFLAGS += -fno-strict-aliasing -fPIE KBUILD_CFLAGS += -Wundef KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING @@ -36,7 +36,10 @@ 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) -KBUILD_CFLAGS += $(call cc-disable-warning, gnu) +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 94b05e4451dd3..7d15a85d579fa 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -11,12 +11,12 @@ cflags-y := $(KBUILD_CFLAGS) cflags-$(CONFIG_X86_32) := -march=i386 cflags-$(CONFIG_X86_64) := -mcmodel=small -cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ -std=gnu11 \ +cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ -std=gnu11 -fms-extensions \ -fPIC -fno-strict-aliasing -mno-red-zone \ -mno-mmx -mno-sse -fshort-wchar \ -Wno-pointer-sign \ $(call cc-disable-warning, address-of-packed-member) \ - $(call cc-disable-warning, gnu) \ + $(if $(CONFIG_CC_IS_CLANG),-Wno-gnu -Wno-microsoft-anon-tag) \ -fno-asynchronous-unwind-tables \ $(CLANG_FLAGS)