[PATCH 22/28] efi/libstub: avoid linking libstub/lib-ksyms.o into vmlinux

Ard Biesheuvel
2020-03-08T08:10:30Z

From: Masahiro Yamada <masahiroy@kernel.org>

drivers/firmware/efi/libstub/Makefile builds a static library, which
is not linked into the main vmlinux target in the ordinary way [arm64],
or at all [ARM, x86].

Since commit 7f2084fa55e6 ("[kbuild] handle exports in lib-y objects
reliably"), any Makefile using lib-y generates lib-ksyms.o which is
linked into vmlinux.

In this case, the following garbage object is linked into vmlinux.

drivers/firmware/efi/libstub/lib-ksyms.o

We do not want to follow the default linking rules for static libraries
built under libstub/ so using subdir-y instead of obj-y is the correct
way to descend into this directory.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20200305055047.6097-1-masahiroy@kernel.org
[ardb: update commit log to clarify that arm64 deviates in this respect]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
drivers/firmware/efi/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
index 317a05cd388b..7a216984552b 100644
--- a/drivers/firmware/efi/Makefile
+++ b/drivers/firmware/efi/Makefile
@@ -20,7 +20,7 @@ obj-$(CONFIG_EFI_VARS_PSTORE) += efi-pstore.o
obj-$(CONFIG_UEFI_CPER) += cper.o
obj-$(CONFIG_EFI_RUNTIME_MAP) += runtime-map.o
obj-$(CONFIG_EFI_RUNTIME_WRAPPERS) += runtime-wrappers.o
-obj-$(CONFIG_EFI_STUB) += libstub/
+subdir-$(CONFIG_EFI_STUB) += libstub
obj-$(CONFIG_EFI_FAKE_MEMMAP) += fake_map.o
obj-$(CONFIG_EFI_BOOTLOADER_CONTROL) += efibc.o
obj-$(CONFIG_EFI_TEST) += test/
--
2.17.1