Commit 7fa6a274 authored by Nathan Chancellor's avatar Nathan Chancellor Committed by Masahiro Yamada
Browse files

x86/build: Do not add -falign flags unconditionally for clang 

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: default avatarkernel test robot <lkp@intel.com>
Reviewed-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Acked-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarNathan Chancellor <nathan@kernel.org>
Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
parent 7c801446

arch/x86/Makefile_32.cpu

+9 −3
Original line number Diff line number Diff line
@@ -4,6 +4,12 @@ 


tune		= $(call cc-option,-mtune=$(1),$(2))



ifdef CONFIG_CC_IS_CLANG

align		:= -falign-functions=0 $(call cc-option,-falign-jumps=0) $(call cc-option,-falign-loops=0)

else

align		:= -falign-functions=0 -falign-jumps=0 -falign-loops=0

endif



cflags-$(CONFIG_M486SX)		+= -march=i486

cflags-$(CONFIG_M486)		+= -march=i486

cflags-$(CONFIG_M586)		+= -march=i586
@@ -19,11 +25,11 @@ cflags-$(CONFIG_MK6) += -march=k6 
# They make zero difference whatsosever to performance at this time.

cflags-$(CONFIG_MK7)		+= -march=athlon

cflags-$(CONFIG_MK8)		+= $(call cc-option,-march=k8,-march=athlon)

cflags-$(CONFIG_MCRUSOE)	+= -march=i686 -falign-functions=0 -falign-jumps=0 -falign-loops=0

cflags-$(CONFIG_MEFFICEON)	+= -march=i686 $(call tune,pentium3) -falign-functions=0 -falign-jumps=0 -falign-loops=0

cflags-$(CONFIG_MCRUSOE)	+= -march=i686 $(align)

cflags-$(CONFIG_MEFFICEON)	+= -march=i686 $(call tune,pentium3) $(align)

cflags-$(CONFIG_MWINCHIPC6)	+= $(call cc-option,-march=winchip-c6,-march=i586)

cflags-$(CONFIG_MWINCHIP3D)	+= $(call cc-option,-march=winchip2,-march=i586)

cflags-$(CONFIG_MCYRIXIII)	+= $(call cc-option,-march=c3,-march=i486) -falign-functions=0 -falign-jumps=0 -falign-loops=0

cflags-$(CONFIG_MCYRIXIII)	+= $(call cc-option,-march=c3,-march=i486) $(align)

cflags-$(CONFIG_MVIAC3_2)	+= $(call cc-option,-march=c3-2,-march=i686)

cflags-$(CONFIG_MVIAC7)		+= -march=i686

cflags-$(CONFIG_MCORE2)		+= -march=i686 $(call tune,core2)