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authorNathan Chancellor <nathan@kernel.org>2021-09-16 21:40:16 +0300
committerMasahiro Yamada <masahiroy@kernel.org>2021-09-19 04:35:53 +0300
commit7fa6a2746616c8de4c40b748c2bb0656e00624ff (patch)
tree2f8097a5df55574d5cf2ca5095cf352f73a6fd61 /arch
parent7c80144626db460bc3969027810a540741865fb1 (diff)
downloadlinux-7fa6a2746616c8de4c40b748c2bb0656e00624ff.tar.xz
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: 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>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/Makefile_32.cpu12
1 files changed, 9 insertions, 3 deletions
diff --git a/arch/x86/Makefile_32.cpu b/arch/x86/Makefile_32.cpu
index e7355f8b51c2..94834c4b5e5e 100644
--- a/arch/x86/Makefile_32.cpu
+++ b/arch/x86/Makefile_32.cpu
@@ -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)