kbuild: Always link module (.ko) from associated (.o)

For extracting the versions and finding the unresolved symbols, we
need multi-part modules to be linked together already, so this
patch separates the building of the modules as a .o file from generating
the .ko in the next step.

scripts/Makefile.build

@@ -224,15 +224,7 @@ quiet_cmd_link_multi-y = LD      $@
 cmd_link_multi-y = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) -r -o $@ $(filter $(addprefix $(obj)/,$($(subst $(obj)/,,$(@:.o=-objs))) $($(subst $(obj)/,,$(@:.o=-y)))),$^)
 
 quiet_cmd_link_multi-m = LD [M]  $@
-cmd_link_multi-m = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) $(LDFLAGS_MODULE) -o $@ $(filter $(addprefix $(obj)/,$($(subst $(obj)/,,$(@:.ko=-objs))) $($(subst $(obj)/,,$(@:.ko=-y)))),$^) init/vermagic.o
-
-quiet_cmd_link_single-m = LD [M]  $@
-cmd_link_single-m = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) $(LDFLAGS_MODULE) -o $@ $< init/vermagic.o
-
-# Don't rebuilt vermagic.o unless we actually are in the init/ dir
-ifneq ($(obj),init)
-init/vermagic.o: ;
-endif
+cmd_link_multi-m = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) $(LDFLAGS_MODULE) -o $@ $(filter $(addprefix $(obj)/,$($(subst $(obj)/,,$(@:.o=-objs))) $($(subst $(obj)/,,$(@:.o=-y)))),$^)
 
 # We would rather have a list of rules like
 # 	foo.o: $(foo-objs)
@@ -241,13 +233,27 @@ endif
 $(multi-used-y) : %.o: $(multi-objs-y) FORCE
 	$(call if_changed,link_multi-y)
 
-$(multi-used-m:.o=.ko) : %.ko: $(multi-objs-m) init/vermagic.o FORCE
+$(multi-used-m) : %.o: $(multi-objs-m) FORCE
+	$(touch-module)
 	$(call if_changed,link_multi-m)
 
-$(single-used-m:.o=.ko) : %.ko: %.o init/vermagic.o FORCE
-	$(call if_changed,link_single-m)
+targets += $(multi-used-y) $(multi-used-m)
+
+#
+# Rule to link modules ( .o -> .ko )
+#
+quiet_cmd_link_module = LD [M]  $@
+cmd_link_module = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) $(LDFLAGS_MODULE) -o $@ $< init/vermagic.o
+
+# Don't rebuilt vermagic.o unless we actually are in the init/ dir
+ifneq ($(obj),init)
+init/vermagic.o: ;
+endif
+
+$(single-used-m:.o=.ko) $(multi-used-m:.o=.ko): %.ko: %.o init/vermagic.o FORCE
+	$(call if_changed,link_module)
 
-targets += $(multi-used-y) $(multi-used-m:.o=.ko) $(single-used-m:.o=.ko)
+targets += $(single-used-m:.o=.ko) $(multi-used-m:.o=.ko)
 
 # Compile programs on the host
 # ===========================================================================