The linker only emits the BTI veneers if *all* input objects have GNU_PROPERTY_AARCH64_FEATURE_1_BTI. All the kernel's objects now advertise it, but if some object stops doing so, BTI veneers silently stop getting created on >128MB kernels, resulting in BTI exceptions at runtime.
Force BTI veneers enabled with "-z force-bti" to prevent a single bad object from ruining things. This also emits a warning (or error with CONFIG_WERROR) if any objects are missing the bit. Signed-off-by: Josh Poimboeuf <[email protected]> --- arch/arm64/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 4eee721c0b278..d0db9a6766a2f 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -25,6 +25,7 @@ endif ifeq ($(CONFIG_ARM64_BTI_KERNEL),y) KBUILD_AFLAGS += -include $(srctree)/arch/arm64/include/asm/bti-note.h +LDFLAGS_vmlinux += $(call ld-option,-z force-bti) endif cc_has_k_constraint := $(call try-run,echo \ -- 2.55.0
