From: Matthias Kaehlcke mka@chromium.org
commit 20c6c189045539d29f4854d92b7ea9c329e1edfc upstream.
The clang warning 'address-of-packed-member' is disabled for the general kernel code, also disable it for the x86 boot code.
This suppresses a bunch of warnings like this when building with clang:
./arch/x86/include/asm/processor.h:535:30: warning: taking address of packed member 'sp0' of class or structure 'x86_hw_tss' may result in an unaligned pointer value [-Waddress-of-packed-member] return this_cpu_read_stable(cpu_tss.x86_tss.sp0); ^~~~~~~~~~~~~~~~~~~ ./arch/x86/include/asm/percpu.h:391:59: note: expanded from macro 'this_cpu_read_stable' #define this_cpu_read_stable(var) percpu_stable_op("mov", var) ^~~ ./arch/x86/include/asm/percpu.h:228:16: note: expanded from macro 'percpu_stable_op' : "p" (&(var))); ^~~
Signed-off-by: Matthias Kaehlcke mka@chromium.org Cc: Doug Anderson dianders@chromium.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Masahiro Yamada yamada.masahiro@socionext.com Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Link: http://lkml.kernel.org/r/20170725215053.135586-1-mka@chromium.org Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/boot/compressed/Makefile | 1 + 1 file changed, 1 insertion(+)
--- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -30,6 +30,7 @@ KBUILD_CFLAGS += $(cflags-y) KBUILD_CFLAGS += -mno-mmx -mno-sse KBUILD_CFLAGS += $(call cc-option,-ffreestanding) KBUILD_CFLAGS += $(call cc-option,-fno-stack-protector) +KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member)
KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ GCOV_PROFILE := n