[PATCH 07/11] efi/libstub: Disable some warnings for x86{,_64}

[Ard Biesheuvel]

From: Nathan Chancellor <natechancellor@xxxxxxxxx>

When building the kernel with Clang, some disabled warnings appear
because this Makefile overrides KBUILD_CFLAGS for x86{,_64}. Add them to
this list so that the build is clean again.

-Wpointer-sign was disabled for the whole kernel before the beginning
of git history.

-Waddress-of-packed-member was disabled for the whole kernel in
commit bfb38988c51e ("kbuild: clang: Disable 'address-of-packed-member'
warning") and for x86/boot/compressed in commit 20c6c1890455 ("x86/boot:
Disable the address-of-packed-member compiler warning").

-Wgnu was disabled for the whole kernel in commit 61163efae020 ("kbuild:
LLVMLinux: Add Kbuild support for building kernel with Clang") and for
x86/boot/compressed in commit 6c3b56b19730 ("x86/boot: Disable Clang
warnings about GNU extensions").

Link: https://github.com/ClangBuiltLinux/linux/issues/112
Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Reviewed-by: Sedat Dilek <sedat.dilek@xxxxxxxxx>
Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
 drivers/firmware/efi/libstub/Makefile | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index c51627660dbb..d9845099635e 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -9,7 +9,10 @@ cflags-$(CONFIG_X86_32)		:= -march=i386
 cflags-$(CONFIG_X86_64)		:= -mcmodel=small
 cflags-$(CONFIG_X86)		+= -m$(BITS) -D__KERNEL__ -O2 \
 				   -fPIC -fno-strict-aliasing -mno-red-zone \
-				   -mno-mmx -mno-sse -fshort-wchar
+				   -mno-mmx -mno-sse -fshort-wchar \
+				   -Wno-pointer-sign \
+				   $(call cc-disable-warning, address-of-packed-member) \
+				   $(call cc-disable-warning, gnu)
 
 # arm64 uses the full KBUILD_CFLAGS so it's necessary to explicitly
 # disable the stackleak plugin
-- 
2.19.1