From: "H.J. Lu" <hjl.to...@gmail.com> When Indirect Branch Tracking (IBT) is enabled, vDSO functions may be called indirectly, and must have ENDBR32 or ENDBR64 as the first instruction. The compiler must support -fcf-protection=branch so that it can be used to compile vDSO.
Signed-off-by: H.J. Lu <hjl.to...@gmail.com> Signed-off-by: Yu-cheng Yu <yu-cheng...@intel.com> Acked-by: Andy Lutomirski <l...@kernel.org> --- arch/x86/entry/vdso/Makefile | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 215376d975a2..1f1b6893068a 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -94,6 +94,10 @@ endif $(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) +ifdef CONFIG_X86_BRANCH_TRACKING_USER +$(vobjs) $(vobjs32): KBUILD_CFLAGS += -fcf-protection=branch +endif + # # vDSO code runs in userspace and -pg doesn't help with profiling anyway. # -- 2.21.0
