Early prototypes of Clang with asm goto support produce 6 instances of the following warning:
In file included from arch/x86/boot/compressed/misc.h:20: In file included from ./include/linux/elf.h:5: In file included from ./arch/x86/include/asm/elf.h:8: In file included from ./include/linux/thread_info.h:38: In file included from ./arch/x86/include/asm/thread_info.h:53: ./arch/x86/include/asm/cpufeature.h:150:2: warning: "Compiler lacks ASM_GOTO support. Add -D __BPF_TRACING__ to your compiler arguments" [-W#warnings] your compiler arguments" ^ Since 6 files under arch/x86/boot/compressed/ include arch/x86/boot/compressed/misc.h AND arch/x86/boot/compressed/Makefile happens to redefine KBUILD_CFLAGS, which set these variables in the top level MAKEFILE. Suggested-by: Borislav Petkov <[email protected]> Signed-off-by: Nick Desaulniers <[email protected]> --- v1 -> v2: Updated commit message to provide more context as per Borislav. arch/x86/boot/compressed/Makefile | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 28764dacf018..158c0b4e178a 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -56,6 +56,13 @@ KBUILD_LDFLAGS += $(shell $(LD) --help 2>&1 | grep -q "\-z noreloc-overflow" \ endif LDFLAGS_vmlinux := -T +# check for 'asm goto' +ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLAGS)), y) + CC_HAVE_ASM_GOTO := 1 + KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO + KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO +endif + hostprogs-y := mkpiggy HOST_EXTRACFLAGS += -I$(srctree)/tools/include -- 2.19.0.605.g01d371f741-goog
