[PATCH v1 2/3] arm64: Only link libstub to final vmlinux

[Tiezhu Yang]

Since the efistub functions are useless for stack unwinder, they can be
ignored by objtool. No need to link libstub to the vmlinux.o, only link
libstub to the final vmlinux. Otherwise, there may be objtool warnings
when arm64 supports objtool, this is to make consistent with the other
archs that use libstub.

Link: https://lore.kernel.org/lkml/pq4h7jgndnt6p45lj4kgubxjd5gidfetugcuf5rcxzxxanzetd@6rrlpjnjsmuy/
Suggested-by: Josh Poimboeuf <jpoimboe at kernel.org>
Signed-off-by: Tiezhu Yang <yangtiezhu at loongson.cn>
---
 arch/arm64/Makefile | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 73a10f65ce8b..038f37ef2143 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -156,7 +156,10 @@ KBUILD_CPPFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
 KBUILD_AFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
 
 libs-y		:= arch/arm64/lib/ $(libs-y)
-libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
+
+ifdef CONFIG_EFI_STUB
+KBUILD_VMLINUX_LIBS_PRELINK += $(objtree)/drivers/firmware/efi/libstub/lib.a
+endif
 
 # Default target when executing plain make
 boot		:= arch/arm64/boot
-- 
2.42.0