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authorNathan Chancellor <nathan@kernel.org>2025-10-30 21:26:28 -0400
committerNathan Chancellor <nathan@kernel.org>2025-10-30 21:26:28 -0400
commit5ff8ad3909524ad55297a434f87c238224825bf4 (patch)
tree4f0ded600367eb62f22793745a553600b68b50af /arch
parentc4781dc3d1cf0e017e1f290607ddc56cfe187afc (diff)
downloadlinux-5ff8ad3909524ad55297a434f87c238224825bf4.tar.gz
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 <brauner@kernel.org> Closes: https://lore.kernel.org/20251030-meerjungfrau-getrocknet-7b46eacc215d@brauner/ Reviewed-by: Christian Brauner <brauner@kernel.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/kernel/vdso32/Makefile3
-rw-r--r--arch/loongarch/vdso/Makefile2
-rw-r--r--arch/parisc/boot/compressed/Makefile2
-rw-r--r--arch/powerpc/boot/Makefile3
-rw-r--r--arch/s390/Makefile3
-rw-r--r--arch/s390/purgatory/Makefile3
-rw-r--r--arch/x86/Makefile4
-rw-r--r--arch/x86/boot/compressed/Makefile7
8 files changed, 18 insertions, 9 deletions
diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile
index ffa3536581f670..9d0efed91414cb 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 d8316f99348240..c0cc3ca5da9f4b 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 17c42d718eb336..f8481e4e9d2141 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 c47b78c1d3e7ef..f1a4761ebd44b7 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 b4769241332bb9..8578361133a4ba 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 bd39b36e7bd688..0c196a5b194af0 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 4db7e4bf69f5cd..e20e25b8b16ceb 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 += $(CLANG_FLAGS)
ifdef CONFIG_CC_IS_CLANG
REALMODE_CFLAGS += -Wno-gnu
+REALMODE_CFLAGS += -Wno-microsoft-anon-tag
endif
export REALMODE_CFLAGS
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 74657589264dfa..68f9d7a1683b57 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -25,7 +25,7 @@ targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
# avoid errors with '-march=i386', and future flags may depend on the target to
# be valid.
KBUILD_CFLAGS := -m$(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