6.1-stable review patch. If anyone has any objections, please let me know.
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From: Nathan Chancellor nathan@kernel.org
[ 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@kernel.org Reviewed-by: Nick Desaulniers ndesaulniers@google.com Tested-by: Linux Kernel Functional Testing lkft@linaro.org Tested-by: Anders Roxell anders.roxell@linaro.org Signed-off-by: Masahiro Yamada masahiroy@kernel.org Stable-dep-of: d677ce521334 ("powerpc/vdso: Drop -mstack-protector-guard flags in 32-bit files with clang") Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/kernel/vdso/Makefile | 5 +++++ 1 file changed, 5 insertions(+)
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)