-obj-y += kernel/
-obj-y += mm/
-obj-y += crypto/
-obj-y += appldata/
-obj-y += hypfs/
-obj-y += kvm/
+obj-y += kernel/
+obj-y += mm/
+obj-$(CONFIG_KVM) += kvm/
+obj-$(CONFIG_CRYPTO_HW) += crypto/
+obj-$(CONFIG_S390_HYPFS_FS) += hypfs/
+obj-$(CONFIG_APPLDATA_BASE) += appldata/
+obj-$(CONFIG_MATHEMU) += math-emu/