This is a note to let you know that I've just added the patch titled
powerpc/vdso: Remove an unsupported flag from vgettimeofday-32.o with clang
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-vdso-remove-an-unsupported-flag-from-vgettim.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a1fd4ceb1d8fb517404405ad41a1b758dcfa0b02
Author: Nathan Chancellor <nathan@xxxxxxxxxx>
Date: Wed Jan 11 20:05:05 2023 -0700
powerpc/vdso: Remove an unsupported flag from vgettimeofday-32.o with clang
[ Upstream commit 05e05bfc92d196669a3d087fc34d3998b6ddb758 ]
When clang's -Qunused-arguments is dropped from KBUILD_CPPFLAGS, it
warns:
clang-16: error: argument unused during compilation: '-fno-stack-clash-protection' [-Werror,-Wunused-command-line-argument]
This warning happens because vgettimeofday-32.c gets its base CFLAGS
from the main kernel, which may contain flags that are only supported on
a 64-bit target but not a 32-bit one, which is the case here.
-fstack-clash-protection and its negation are only suppported by the
64-bit powerpc target but that flag is included in an invocation for a
32-bit powerpc target, so clang points out that while the flag is one
that it recognizes, it is not actually used by this compiler job.
To eliminate the warning, remove -fno-stack-clash-protection from
vgettimeofday-32.c's CFLAGS when using clang, as has been done for other
flags previously.
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Tested-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
Tested-by: Anders Roxell <anders.roxell@xxxxxxxxxx>
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Stable-dep-of: d677ce521334 ("powerpc/vdso: Drop -mstack-protector-guard flags in 32-bit files with clang")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile
index d4023bceec348..7e69e87fbf744 100644
--- a/arch/powerpc/kernel/vdso/Makefile
+++ b/arch/powerpc/kernel/vdso/Makefile
@@ -16,6 +16,11 @@ ifneq ($(c-gettimeofday-y),)
CFLAGS_vgettimeofday-32.o += -ffreestanding -fasynchronous-unwind-tables
CFLAGS_REMOVE_vgettimeofday-32.o = $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_vgettimeofday-32.o += -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc
+ # This flag is supported by clang for 64-bit but not 32-bit so it will cause
+ # an unused command line flag warning for this file.
+ ifdef CONFIG_CC_IS_CLANG
+ CFLAGS_REMOVE_vgettimeofday-32.o += -fno-stack-clash-protection
+ endif
CFLAGS_vgettimeofday-64.o += -include $(c-gettimeofday-y)
CFLAGS_vgettimeofday-64.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
CFLAGS_vgettimeofday-64.o += $(call cc-option, -fno-stack-protector)
