Only reserve x18 with CONFIG_SHADOW_CALL_STACK. Note that all external kernel modules must also have x18 reserved if the kernel uses SCS. Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> --- arch/arm64/Makefile | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 1c7b276bc7c5..ef76101201b2 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -55,7 +55,7 @@ endif KBUILD_CFLAGS += -mgeneral-regs-only $(lseinstr) $(brokengasinst) \ $(compat_vdso) $(cc_has_k_constraint) -KBUILD_CFLAGS += -fno-asynchronous-unwind-tables -ffixed-x18 +KBUILD_CFLAGS += -fno-asynchronous-unwind-tables KBUILD_CFLAGS += $(call cc-disable-warning, psabi) KBUILD_AFLAGS += $(lseinstr) $(brokengasinst) $(compat_vdso) @@ -72,6 +72,10 @@ stack_protector_prepare: prepare0 include/generated/asm-offsets.h)) endif +ifeq ($(CONFIG_SHADOW_CALL_STACK), y) +KBUILD_CFLAGS += -ffixed-x18 +endif + ifeq ($(CONFIG_CPU_BIG_ENDIAN), y) KBUILD_CPPFLAGS += -mbig-endian CHECKFLAGS += -D__AARCH64EB__ -- 2.23.0.866.gb869b98d4c-goog
