4.4-stable review patch. If anyone has any objections, please let me know.
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From: Stefan Agner stefan@agner.ch
commit ef8c4ed9db80261f397f0c0bf723684601ae3b52 upstream.
When using a GCC cross toolchain which is not in a compiled in Clang search path, Clang reverts to the system assembler and linker. This leads to assembler or linker errors, depending on which tool is first used for a given architecture.
It seems that Clang is not searching $PATH for a matching assembler or linker.
Make sure that Clang picks up the correct assembler or linker by passing the cross compilers bin directory as search path.
This allows to use Clang provided by distributions with GCC toolchains not in /usr/bin.
Link: https://github.com/ClangBuiltLinux/linux/issues/78 Signed-off-by: Stefan Agner stefan@agner.ch Reviewed-and-tested-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Masahiro Yamada yamada.masahiro@socionext.com [nc: Adjust context] Signed-off-by: Nathan Chancellor natechancellor@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- Makefile | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/Makefile +++ b/Makefile @@ -610,13 +610,15 @@ all: vmlinux ifeq ($(cc-name),clang) ifneq ($(CROSS_COMPILE),) CLANG_TARGET := --target=$(notdir $(CROSS_COMPILE:%-=%)) -GCC_TOOLCHAIN := $(realpath $(dir $(shell which $(LD)))/..) +GCC_TOOLCHAIN_DIR := $(dir $(shell which $(LD))) +CLANG_PREFIX := --prefix=$(GCC_TOOLCHAIN_DIR) +GCC_TOOLCHAIN := $(realpath $(GCC_TOOLCHAIN_DIR)/..) endif ifneq ($(GCC_TOOLCHAIN),) CLANG_GCC_TC := --gcc-toolchain=$(GCC_TOOLCHAIN) endif -KBUILD_CFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC) -KBUILD_AFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC) +KBUILD_CFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC) $(CLANG_PREFIX) +KBUILD_AFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC) $(CLANG_PREFIX) KBUILD_CFLAGS += $(call cc-option, -no-integrated-as) KBUILD_AFLAGS += $(call cc-option, -no-integrated-as) endif