backport of 14831fad73f5 for 5.10 and 5.4

From: Nick Desaulniers <ndesaulniers@google.com>
To: Sasha Levin <sashal@kernel.org>, Greg KH <gregkh@linuxfoundation.org>
Cc: "# 3.4.x" <stable@vger.kernel.org>,
	Lucas Henneman <henneman@google.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Nathan Chancellor <nathan@kernel.org>,
	Will Deacon <will@kernel.org>,
	llvm@lists.linux.dev
Subject: backport of 14831fad73f5 for 5.10 and 5.4
Date: Thu, 18 Nov 2021 11:30:38 -0800	[thread overview]
Message-ID: <CAKwvOdmaGrk80s5T9uDMd-XEVTOUupaCxiU1mbtkk9K276KS5w@mail.gmail.com> (raw)

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Dear stable kernel maintainers,
Please consider applying the attached backport of 14831fad73f5 to
linux-5.10.y and linux-5.4.y.

14831fad73f5 first landed in v5.16-rc1.

There was a minor conflict due to missing e35123d83ee3 ("arm64: lto:
Strengthen READ_ONCE() to acquire when CONFIG_LTO=y") which first
landed in v5.11-rc1.

It fixes a minor warning observed during `make mrproper` for Android
kernel builds.
-- 
Thanks,
~Nick Desaulniers

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From 6f18bb92716ad8c70e4738e77ff82e98f02386e1 Mon Sep 17 00:00:00 2001
From: Nick Desaulniers <ndesaulniers@google.com>
Date: Tue, 19 Oct 2021 15:36:45 -0700
Subject: [PATCH] arm64: vdso32: suppress error message for 'make mrproper'

commit 14831fad73f5ac30ac61760487d95a538e6ab3cb upstream.

When running the following command without arm-linux-gnueabi-gcc in
one's $PATH, the following warning is observed:

$ ARCH=arm64 CROSS_COMPILE_COMPAT=arm-linux-gnueabi- make -j72 LLVM=1 mrproper
make[1]: arm-linux-gnueabi-gcc: No such file or directory

This is because KCONFIG is not run for mrproper, so CONFIG_CC_IS_CLANG
is not set, and we end up eagerly evaluating various variables that try
to invoke CC_COMPAT.

This is a similar problem to what was observed in
commit dc960bfeedb0 ("h8300: suppress error messages for 'make clean'")

Reported-by: Lucas Henneman <henneman@google.com>
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
[nd: adjusted context due to missing e35123d83ee3]
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20211019223646.1146945-4-ndesaulniers@google.com
Signed-off-by: Will Deacon <will@kernel.org>
---
 arch/arm64/kernel/vdso32/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile
index 40dffe60b845..51957a585e66 100644
--- a/arch/arm64/kernel/vdso32/Makefile
+++ b/arch/arm64/kernel/vdso32/Makefile
@@ -32,7 +32,8 @@ cc32-as-instr = $(call try-run,\
 # As a result we set our own flags here.
 
 # KBUILD_CPPFLAGS and NOSTDINC_FLAGS from top-level Makefile
-VDSO_CPPFLAGS := -D__KERNEL__ -nostdinc -isystem $(shell $(CC_COMPAT) -print-file-name=include)
+VDSO_CPPFLAGS := -D__KERNEL__ -nostdinc
+VDSO_CPPFLAGS += -isystem $(shell $(CC_COMPAT) -print-file-name=include)
 VDSO_CPPFLAGS += $(LINUXINCLUDE)
 
 # Common C and assembly flags
-- 
2.34.0.rc2.393.gf8c9666880-goog

