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x86/build: Remove stale cc-option checks
cc-option, __cc-option, cc-option-yn, and cc-disable-warning all invoke the compiler during build time, and can slow down the build when these checks become stale for our supported compilers, whose minimally supported versions increases over time. See Documentation/process/changes.rst for the current supported minimal versions (GCC 4.9+, clang 10.0.1+). Compiler version support for these flags may be verified on godbolt.org. The following flags are supported by all supported versions of GCC and Clang. Remove their cc-option, __cc-option, and cc-option-yn tests. -Wno-address-of-packed-member -mno-avx -m32 -mno-80387 -march=k8 -march=nocona -march=core2 -march=atom -mtune=generic -mfentry [ mingo: Fixed regression on GCC, via partial revert of the stack-boundary changes. ] Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://github.com/ClangBuiltLinux/linux/issues/1436 Link: https://lkml.kernel.org/r/20210812183848.1519994-1-ndesaulniers@google.com
This commit is contained in:
Nick Desaulniers
Ingo Molnar
parent
36a21d5172
commit
989ceac799
@ -31,8 +31,8 @@ REALMODE_CFLAGS := -m16 -g -Os -DDISABLE_BRANCH_PROFILING \
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REALMODE_CFLAGS += -ffreestanding
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REALMODE_CFLAGS += -fno-stack-protector
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REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member)
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REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4))
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REALMODE_CFLAGS += -Wno-address-of-packed-member
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REALMODE_CFLAGS += $(cc_stack_align4)
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REALMODE_CFLAGS += $(CLANG_FLAGS)
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export REALMODE_CFLAGS
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@ -48,8 +48,7 @@ export BITS
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#
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# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
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#
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KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
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KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
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KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
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# Intel CET isn't enabled in the kernel
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KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
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@ -59,9 +58,8 @@ ifeq ($(CONFIG_X86_32),y)
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UTS_MACHINE := i386
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CHECKFLAGS += -D__i386__
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biarch := $(call cc-option,-m32)
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KBUILD_AFLAGS += $(biarch)
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KBUILD_CFLAGS += $(biarch)
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KBUILD_AFLAGS += -m32
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KBUILD_CFLAGS += -m32
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KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
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@ -72,7 +70,7 @@ ifeq ($(CONFIG_X86_32),y)
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# Align the stack to the register width instead of using the default
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# alignment of 16 bytes. This reduces stack usage and the number of
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# alignment instructions.
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KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4))
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KBUILD_CFLAGS += $(cc_stack_align4)
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# CPU-specific tuning. Anything which can be shared with UML should go here.
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include arch/x86/Makefile_32.cpu
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@ -93,7 +91,6 @@ else
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UTS_MACHINE := x86_64
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CHECKFLAGS += -D__x86_64__
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biarch := -m64
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KBUILD_AFLAGS += -m64
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KBUILD_CFLAGS += -m64
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@ -104,7 +101,7 @@ else
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KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
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# Don't autogenerate traditional x87 instructions
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KBUILD_CFLAGS += $(call cc-option,-mno-80387)
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KBUILD_CFLAGS += -mno-80387
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KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
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# By default gcc and clang use a stack alignment of 16 bytes for x86.
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@ -114,20 +111,17 @@ else
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# default alignment which keep the stack *mis*aligned.
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# Furthermore an alignment to the register width reduces stack usage
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# and the number of alignment instructions.
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KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8))
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KBUILD_CFLAGS += $(cc_stack_align8)
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# Use -mskip-rax-setup if supported.
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KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
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# FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
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cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
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cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
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cflags-$(CONFIG_MCORE2) += \
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$(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
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cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \
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$(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
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cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
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cflags-$(CONFIG_MK8) += -march=k8
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cflags-$(CONFIG_MPSC) += -march=nocona
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cflags-$(CONFIG_MCORE2) += -march=core2
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cflags-$(CONFIG_MATOM) += -march=atom
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cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic
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KBUILD_CFLAGS += $(cflags-y)
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KBUILD_CFLAGS += -mno-red-zone
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@ -158,18 +152,6 @@ export CONFIG_X86_X32_ABI
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ifdef CONFIG_FUNCTION_GRAPH_TRACER
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ifndef CONFIG_HAVE_FENTRY
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ACCUMULATE_OUTGOING_ARGS := 1
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else
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ifeq ($(call cc-option-yn, -mfentry), n)
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ACCUMULATE_OUTGOING_ARGS := 1
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# GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
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# If '-Os' is enabled, disable it and print a warning.
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ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
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undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
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$(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE. Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
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endif
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endif
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endif
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endif
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@ -193,7 +175,7 @@ ifdef CONFIG_RETPOLINE
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# only been fixed starting from gcc stable version 8.4.0 and
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# onwards, but not for older ones. See gcc bug #86952.
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ifndef CONFIG_CC_IS_CLANG
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KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
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KBUILD_CFLAGS += -fno-jump-tables
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endif
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endif
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