[PATCH 4.14 208/229] kbuild: clear LDFLAGS in the top Makefile

Greg Kroah-Hartman
2022-08-23T10:20:19Z

From: Masahiro Yamada <yamada.masahiro@socionext.com>

commit ce99d0bf312daf0178e640da9e3c93b773a67e7d upstream.

Currently LDFLAGS is not cleared, so same flags are accumulated in
LDFLAGS when the top Makefile is recursively invoked.

I found unneeded rebuild for ARCH=arm64 when CONFIG_TRIM_UNUSED_KSYMS
is enabled. If include/generated/autoksyms.h is updated, the top
Makefile is recursively invoked, then arch/arm64/Makefile adds one
more '-maarch64linux'. Due to the command line change, modules are
rebuilt needlessly.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Makefile | 1 +
1 file changed, 1 insertion(+)

--- a/Makefile
+++ b/Makefile
@@ -426,6 +426,7 @@ KBUILD_CFLAGS_KERNEL :=
KBUILD_AFLAGS_MODULE := -DMODULE
KBUILD_CFLAGS_MODULE := -DMODULE
KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds
+LDFLAGS :=
GCC_PLUGINS_CFLAGS :=
CLANG_FLAGS :=