kbuild: Rearrange Rules.make

This patch doesn't change anything but the order (and some comments) in
Rules.make. The reason for that is that we use Rules.make for three
different purposes, fastdep, modules_install and the actual building.

As an example, we don't need all the dependencies and saved command lines
when installing modules, so it'll speed up this pass to only include the
rules which will actually get used.

Rules.make

@@ -85,7 +85,105 @@ subdir-obj-y := $(foreach o,$(obj-y),$(if $(filter-out $(o),$(notdir $(o))),$(o)
 real-objs-y := $(foreach m, $(filter-out $(subdir-obj-y), $(obj-y)), $(if $($(m:.o=-objs)),$($(m:.o=-objs)),$(m))) $(EXTRA_TARGETS)
 real-objs-m := $(foreach m, $(obj-m), $(if $($(m:.o=-objs)),$($(m:.o=-objs)),$(m)))
 
-# Get things started.
+
+# We're called for one of three purposes:
+# o fastdep: build module version files (.ver) for $(export-objs) in
+#   the current directory
+# o modules_install: install the modules in the current directory
+# o build: When no target is given, first_rule is the default and
+#   will build the built-in and modular objects in this dir
+#   (or a subset thereof, depending on $(KBUILD_MODULES),$(KBUILD_BUILTIN)
+#   When targets are given directly (like foo.o), we just build these
+#   targets (That happens when someone does make some/dir/foo.[ois])
+
+ifeq ($(MAKECMDGOALS),fastdep)
+
+# ===========================================================================
+# Module versions
+# ===========================================================================
+
+ifneq "$(strip $(export-objs))" ""
+
+MODVERDIR := $(TOPDIR)/include/linux/modules/$(RELDIR)
+
+#
+# Added the SMP separator to stop module accidents between uniprocessor
+# and SMP Intel boxes - AC - from bits by Michael Chastain
+#
+
+ifdef CONFIG_SMP
+	genksyms_smp_prefix := -p smp_
+else
+	genksyms_smp_prefix := 
+endif
+
+# We don't track dependencies for .ver files, so we FORCE to check
+# them always (i.e. always at "make dep" time).
+
+quiet_cmd_create_ver = Creating include/linux/modules/$(RELDIR)/$*.ver
+cmd_create_ver = $(CC) $(CFLAGS) $(EXTRA_CFLAGS) -E -D__GENKSYMS__ $< | \
+		 $(GENKSYMS) $(genksyms_smp_prefix) -k $(VERSION).$(PATCHLEVEL).$(SUBLEVEL) > $@.tmp
+
+$(MODVERDIR)/%.ver: %.c FORCE
+	@mkdir -p $(dir $@)
+	@$(call cmd,cmd_create_ver)
+	@if [ -r $@ ] && cmp -s $@ $@.tmp; then \
+	  rm -f $@.tmp; \
+	else \
+	  touch $(TOPDIR)/include/linux/modversions.h; \
+	  mv -f $@.tmp $@; \
+	fi
+
+# updates .ver files but not modversions.h
+fastdep: $(addprefix $(MODVERDIR)/,$(export-objs:.o=.ver))
+ifneq ($(export-objs),)
+	@mkdir -p $(TOPDIR)/.tmp_export-objs/modules/$(RELDIR)
+	@touch $(addprefix $(TOPDIR)/.tmp_export-objs/modules/$(RELDIR)/,$(export-objs:.o=.ver))
+endif
+
+# Descending when making module versions
+# ---------------------------------------------------------------------------
+
+fastdep-list := $(addprefix _sfdep_,$(subdir-ymn))
+
+.PHONY: fastdep $(fastdep-list)
+
+fastdep: $(fastdep-list)
+
+$(fastdep-list):
+	@$(MAKE) -C $(patsubst _sfdep_%,%,$@) fastdep
+
+
+endif # export-objs 
+
+else # ! fastdep
+ifeq ($(MAKECMDGOALS),modules_install)
+
+# ==========================================================================
+# Installing modules
+# ==========================================================================
+
+modinst-list := $(addprefix _modinst_,$(subdir-ym))
+
+.PHONY: modules_install _modinst_ $(modinst-list)
+
+modules_install: $(modinst-list)
+ifneq ($(obj-m),)
+	@echo Installing modules in $(MODLIB)/kernel/$(RELDIR)
+	@mkdir -p $(MODLIB)/kernel/$(RELDIR)
+	@cp $(obj-m) $(MODLIB)/kernel/$(RELDIR)
+else
+	@echo -n
+endif
+
+$(modinst-list):
+	@$(MAKE) -C $(patsubst _modinst_%,%,$@) modules_install
+
+
+else # ! modules_install
+
+# ==========================================================================
+# Building
 # ==========================================================================
 
 # If a Makefile does define neither O_TARGET nor L_TARGET,
@@ -257,18 +355,6 @@ $(host-progs-multi): %: $(host-progs-multi-objs) FORCE
 	$(call if_changed,host_cc__o)
 
 
-# Descending when making module versions
-# ---------------------------------------------------------------------------
-
-fastdep-list := $(addprefix _sfdep_,$(subdir-ymn))
-
-.PHONY: fastdep $(fastdep-list)
-
-fastdep: $(fastdep-list)
-
-$(fastdep-list):
-	@$(MAKE) -C $(patsubst _sfdep_%,%,$@) fastdep
-
 # Descending when building
 # ---------------------------------------------------------------------------
 
@@ -281,24 +367,12 @@ sub_dirs: $(subdir-list)
 $(subdir-list):
 	@$(MAKE) -C $(patsubst _subdir_%,%,$@)
 
-# Descending and installing modules
-# ---------------------------------------------------------------------------
-
-modinst-list := $(addprefix _modinst_,$(subdir-ym))
+endif # ! modules_install
+endif # ! fastdep
 
-.PHONY: modules_install _modinst_ $(modinst-list)
-
-modules_install: $(modinst-list)
-ifneq ($(obj-m),)
-	@echo Installing modules in $(MODLIB)/kernel/$(RELDIR)
-	@mkdir -p $(MODLIB)/kernel/$(RELDIR)
-	@cp $(obj-m) $(MODLIB)/kernel/$(RELDIR)
-else
-	@echo -n
-endif
-
-$(modinst-list):
-	@$(MAKE) -C $(patsubst _modinst_%,%,$@) modules_install
+# ===========================================================================
+# Generic stuff
+# ===========================================================================
 
 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
 # ---------------------------------------------------------------------------
@@ -319,51 +393,6 @@ script:
 # Exporting objects are: all objects that define symbol tables
 #
 
-ifdef CONFIG_MODVERSIONS
-ifneq "$(strip $(export-objs))" ""
-
-MODVERDIR := $(TOPDIR)/include/linux/modules/$(RELDIR)
-
-#
-# Added the SMP separator to stop module accidents between uniprocessor
-# and SMP Intel boxes - AC - from bits by Michael Chastain
-#
-
-ifdef CONFIG_SMP
-	genksyms_smp_prefix := -p smp_
-else
-	genksyms_smp_prefix := 
-endif
-
-# We don't track dependencies for .ver files, so we FORCE to check
-# them always (i.e. always at "make dep" time).
-
-quiet_cmd_create_ver = Creating include/linux/modules/$(RELDIR)/$*.ver
-cmd_create_ver = $(CC) $(CFLAGS) $(EXTRA_CFLAGS) -E -D__GENKSYMS__ $< | \
-		 $(GENKSYMS) $(genksyms_smp_prefix) -k $(VERSION).$(PATCHLEVEL).$(SUBLEVEL) > $@.tmp
-
-$(MODVERDIR)/%.ver: %.c FORCE
-	@mkdir -p $(dir $@)
-	@$(call cmd,cmd_create_ver)
-	@if [ -r $@ ] && cmp -s $@ $@.tmp; then \
-	  rm -f $@.tmp; \
-	else \
-	  touch $(TOPDIR)/include/linux/modversions.h; \
-	  mv -f $@.tmp $@; \
-	fi
-
-# updates .ver files but not modversions.h
-fastdep: $(addprefix $(MODVERDIR)/,$(export-objs:.o=.ver))
-ifneq ($(export-objs),)
-	@mkdir -p $(TOPDIR)/.tmp_export-objs/modules/$(RELDIR)
-	@touch $(addprefix $(TOPDIR)/.tmp_export-objs/modules/$(RELDIR)/,$(export-objs:.o=.ver))
-endif
-
-
-endif # export-objs 
-
-endif # CONFIG_MODVERSIONS
-
 # ---------------------------------------------------------------------------
 # Check if command line has changed