mirror of
https://github.com/torvalds/linux
synced 2024-07-08 20:29:39 +00:00
7fa6a27466
clang does not support -falign-jumps and only recently gained support
for -falign-loops. When one of the configuration options that adds these
flags is enabled, clang warns and all cc-{disable-warning,option} that
follow fail because -Werror gets added to test for the presence of this
warning:
clang-14: warning: optimization flag '-falign-jumps=0' is not supported
[-Wignored-optimization-argument]
To resolve this, add a couple of cc-option calls when building with
clang; gcc has supported these options since 3.2 so there is no point in
testing for their support. -falign-functions was implemented in clang-7,
-falign-loops was implemented in clang-14, and -falign-jumps has not
been implemented yet.
Link: https://lore.kernel.org/r/YSQE2f5teuvKLkON@Ryzen-9-3900X.localdomain/
Link: https://lore.kernel.org/r/20210824022640.2170859-2-nathan@kernel.org/
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
54 lines
2.4 KiB
Plaintext
54 lines
2.4 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0
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# CPU tuning section - shared with UML.
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# Must change only cflags-y (or [yn]), not CFLAGS! That makes a difference for UML.
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tune = $(call cc-option,-mtune=$(1),$(2))
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ifdef CONFIG_CC_IS_CLANG
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align := -falign-functions=0 $(call cc-option,-falign-jumps=0) $(call cc-option,-falign-loops=0)
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else
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align := -falign-functions=0 -falign-jumps=0 -falign-loops=0
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endif
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cflags-$(CONFIG_M486SX) += -march=i486
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cflags-$(CONFIG_M486) += -march=i486
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cflags-$(CONFIG_M586) += -march=i586
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cflags-$(CONFIG_M586TSC) += -march=i586
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cflags-$(CONFIG_M586MMX) += -march=pentium-mmx
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cflags-$(CONFIG_M686) += -march=i686
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cflags-$(CONFIG_MPENTIUMII) += -march=i686 $(call tune,pentium2)
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cflags-$(CONFIG_MPENTIUMIII) += -march=i686 $(call tune,pentium3)
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cflags-$(CONFIG_MPENTIUMM) += -march=i686 $(call tune,pentium3)
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cflags-$(CONFIG_MPENTIUM4) += -march=i686 $(call tune,pentium4)
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cflags-$(CONFIG_MK6) += -march=k6
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# Please note, that patches that add -march=athlon-xp and friends are pointless.
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# They make zero difference whatsosever to performance at this time.
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cflags-$(CONFIG_MK7) += -march=athlon
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cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8,-march=athlon)
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cflags-$(CONFIG_MCRUSOE) += -march=i686 $(align)
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cflags-$(CONFIG_MEFFICEON) += -march=i686 $(call tune,pentium3) $(align)
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cflags-$(CONFIG_MWINCHIPC6) += $(call cc-option,-march=winchip-c6,-march=i586)
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cflags-$(CONFIG_MWINCHIP3D) += $(call cc-option,-march=winchip2,-march=i586)
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cflags-$(CONFIG_MCYRIXIII) += $(call cc-option,-march=c3,-march=i486) $(align)
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cflags-$(CONFIG_MVIAC3_2) += $(call cc-option,-march=c3-2,-march=i686)
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cflags-$(CONFIG_MVIAC7) += -march=i686
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cflags-$(CONFIG_MCORE2) += -march=i686 $(call tune,core2)
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cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom,$(call cc-option,-march=core2,-march=i686)) \
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$(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
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# AMD Elan support
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cflags-$(CONFIG_MELAN) += -march=i486
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# Geode GX1 support
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cflags-$(CONFIG_MGEODEGX1) += -march=pentium-mmx
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cflags-$(CONFIG_MGEODE_LX) += $(call cc-option,-march=geode,-march=pentium-mmx)
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# add at the end to overwrite eventual tuning options from earlier
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# cpu entries
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cflags-$(CONFIG_X86_GENERIC) += $(call tune,generic,$(call tune,i686))
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# Bug fix for binutils: this option is required in order to keep
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# binutils from generating NOPL instructions against our will.
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ifneq ($(CONFIG_X86_P6_NOP),y)
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cflags-y += $(call cc-option,-Wa$(comma)-mtune=generic32,)
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endif
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