From: Nathan Chancellor nathan@kernel.org
commit f634ca650f724347892068489c7920631a3aac6a upstream.
Normally, invocations of $(HOSTCC) include $(KBUILD_HOSTLDFLAGS), which in turn includes $(HOSTLDFLAGS), which allows users to pass in their own flags when linking. However, the 'has_libelf' test does not, meaning that if a user requests a specific linker via HOSTLDFLAGS=-fuse-ld=..., it is not respected and the build might error.
For example, if a user building with clang wants to use all of the LLVM tools without any GNU tools, they might remove all of the GNU tools from their system or PATH then build with
$ make HOSTLDFLAGS=-fuse-ld=lld LLVM=1 LLVM_IAS=1
which says use all of the LLVM tools, the integrated assembler, and ld.lld for linking host executables. Without this change, the build will error because $(HOSTCC) uses its default linker, rather than the one requested via -fuse-ld=..., which is GNU ld in clang's case in a default configuration.
error: Cannot generate ORC metadata for CONFIG_UNWINDER_ORC=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel make[1]: *** [Makefile:1260: prepare-objtool] Error 1
Add $(KBUILD_HOSTLDFLAGS) to the 'has_libelf' test so that the linker choice is respected.
Link: https://github.com/ClangBuiltLinux/linux/issues/479 Signed-off-by: Nathan Chancellor nathan@kernel.org Signed-off-by: Masahiro Yamada masahiroy@kernel.org Cc: Paul Barker paul.barker@sancloud.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/Makefile +++ b/Makefile @@ -1073,7 +1073,7 @@ export mod_sign_cmd HOST_LIBELF_LIBS = $(shell pkg-config libelf --libs 2>/dev/null || echo -lelf)
has_libelf = $(call try-run,\ - echo "int main() {}" | $(HOSTCC) -xc -o /dev/null $(HOST_LIBELF_LIBS) -,1,0) + echo "int main() {}" | $(HOSTCC) $(KBUILD_HOSTLDFLAGS) -xc -o /dev/null $(HOST_LIBELF_LIBS) -,1,0)
ifdef CONFIG_STACK_VALIDATION ifeq ($(has_libelf),1)