Index: head/share/mk/bsd.linker.mk
===================================================================
--- head/share/mk/bsd.linker.mk
+++ head/share/mk/bsd.linker.mk
@@ -71,6 +71,7 @@
 ${X_}LINKER_FEATURES=
 .if ${${X_}LINKER_TYPE} != "bfd" || ${${X_}LINKER_VERSION} > 21750
 ${X_}LINKER_FEATURES+=	build-id
+${X_}LINKER_FEATURES+=	ifunc
 .endif
 .if ${${X_}LINKER_TYPE} != "lld" || ${${X_}LINKER_VERSION} >= 50000
 ${X_}LINKER_FEATURES+=	filter
Index: head/sys/conf/kern.pre.mk
===================================================================
--- head/sys/conf/kern.pre.mk
+++ head/sys/conf/kern.pre.mk
@@ -121,6 +121,9 @@
 .endif
 
 .if ${MACHINE_CPUARCH} == "amd64"
+.if defined(LINKER_FEATURES) && ${LINKER_FEATURES:Mifunc} == ""
+.error amd64 kernel requires linker ifunc support
+.endif
 LDFLAGS+=	-Wl,-z max-page-size=2097152 -Wl,-z common-page-size=4096
 .endif