Rules.make - pub/scm/linux/kernel/git/tglx/history - Git at Google

 #
 # This file contains rules which are shared between multiple Makefiles.
 #

 # Some standard vars

 comma   := ,
 empty   :=
 space   := $(empty) $(empty)

 # Figure out paths
 # ---------------------------------------------------------------------------
 # Find the path relative to the toplevel dir, $(RELDIR), and express
 # the toplevel dir as a relative path from this dir, $(TOPDIR_REL)

 ifeq ($(findstring $(TOPDIR),$(CURDIR)),)
   # Can only happen when something is built out of tree
   RELDIR := $(CURDIR)
   TOPDIR_REL := $(TOPDIR)
 else
   RELDIR := $(subst $(TOPDIR)/,,$(CURDIR))
   TOPDIR_REL := $(subst $(space),,$(foreach d,$(subst /, ,$(RELDIR)),../))
 endif

 # Figure out what we need to build from the various variables
 # ===========================================================================

 # When an object is listed to be built compiled-in and modular,
 # only build the compiled-in version

 obj-m := $(filter-out $(obj-y),$(obj-m))

 # Handle objects in subdirs
 # ---------------------------------------------------------------------------
 # o if we encounter foo/ in $(obj-y), replace it by foo/built-in.o
 #   and add the directory to the list of dirs to descend into: $(subdir-y)
 # o if we encounter foo/ in $(obj-m), remove it from $(obj-m)
 #   and add the directory to the list of dirs to descend into: $(subdir-m)

 __subdir-y	:= $(patsubst %/,%,$(filter %/, $(obj-y)))
 subdir-y	+= $(__subdir-y)
 __subdir-m	:= $(patsubst %/,%,$(filter %/, $(obj-m)))
 subdir-m	+= $(__subdir-m)
 __subdir-n	:= $(patsubst %/,%,$(filter %/, $(obj-n)))
 subdir-n	+= $(__subdir-n)
 __subdir-	:= $(patsubst %/,%,$(filter %/, $(obj-)))
 subdir-		+= $(__subdir-)
 obj-y		:= $(patsubst %/, %/built-in.o, $(obj-y))
 obj-m		:= $(filter-out %/, $(obj-m))

 # If a dir is selected in $(subdir-y) and also mentioned in $(mod-subdirs),
 # add it to $(subdir-m)

 both-m          := $(filter $(mod-subdirs), $(subdir-y))
 subdir-ym	:= $(sort $(subdir-y) $(subdir-m))
 subdir-ymn	:= $(sort $(subdir-ym) $(subdir-n) $(subdir-))

 # export.o is never a composite object, since $(export-objs) has a
 # fixed meaning (== objects which EXPORT_SYMBOL())
 __obj-y = $(filter-out export.o,$(obj-y))
 __obj-m = $(filter-out export.o,$(obj-m))

 # if $(foo-objs) exists, foo.o is a composite object
 __multi-used-y := $(sort $(foreach m,$(__obj-y), $(if $($(m:.o=-objs)), $(m))))
 __multi-used-m := $(sort $(foreach m,$(__obj-m), $(if $($(m:.o=-objs)), $(m))))

 # FIXME: Rip this out later
 # Backwards compatibility: if a composite object is listed in
 # $(list-multi), skip it here, since the Makefile will have an explicit
 # link rule for it

 multi-used-y := $(filter-out $(list-multi),$(__multi-used-y))
 multi-used-m := $(filter-out $(list-multi),$(__multi-used-m))

 # Build list of the parts of our composite objects, our composite
 # objects depend on those (obviously)
 multi-objs-y := $(foreach m, $(multi-used-y), $($(m:.o=-objs)))
 multi-objs-m := $(foreach m, $(multi-used-m), $($(m:.o=-objs)))

 # $(subdir-obj-y) is the list of objects in $(obj-y) which do not live
 # in the local directory
 subdir-obj-y := $(foreach o,$(obj-y),$(if $(filter-out $(o),$(notdir $(o))),$(o)))

 # Replace multi-part objects by their individual parts, look at local dir only
 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.
 # ==========================================================================

 ifndef O_TARGET
 ifndef L_TARGET
 O_TARGET := built-in.o
 endif
 endif

 #	The echo suppresses the "Nothing to be done for first_rule"
 first_rule: $(if $(KBUILD_BUILTIN),$(O_TARGET) $(L_TARGET) $(EXTRA_TARGETS)) \
 	    $(if $(KBUILD_MODULES),$(obj-m)) \
 	    sub_dirs
 	@echo -n

 # Compile C sources (.c)
 # ---------------------------------------------------------------------------

 # If we don't know if built-in or modular, assume built-in.
 # Only happens in Makefiles which override the default first_rule:
 modkern_cflags := $(CFLAGS_KERNEL)

 $(real-objs-y)        : modkern_cflags := $(CFLAGS_KERNEL)
 $(real-objs-y:.o=.i)  : modkern_cflags := $(CFLAGS_KERNEL)
 $(real-objs-y:.o=.s)  : modkern_cflags := $(CFLAGS_KERNEL)
 $(real-objs-y:.o=.lst): modkern_cflags := $(CFLAGS_KERNEL)

 $(real-objs-m)        : modkern_cflags := $(CFLAGS_MODULE)
 $(real-objs-m:.o=.i)  : modkern_cflags := $(CFLAGS_MODULE)
 $(real-objs-m:.o=.lst): modkern_cflags := $(CFLAGS_MODULE)

 $(export-objs)        : export_flags   := $(EXPORT_FLAGS)
 $(export-objs:.o=.i)  : export_flags   := $(EXPORT_FLAGS)
 $(export-objs:.o=.s)  : export_flags   := $(EXPORT_FLAGS)
 $(export-objs:.o=.lst): export_flags   := $(EXPORT_FLAGS)

 c_flags = $(CFLAGS) $(NOSTDINC_FLAGS) $(modkern_cflags) $(EXTRA_CFLAGS) $(CFLAGS_$(*F).o) -DKBUILD_BASENAME=$(subst $(comma),_,$(subst -,_,$(*F))) $(export_flags)

 quiet_cmd_cc_s_c = CC     $(RELDIR)/$@
 cmd_cc_s_c       = $(CC) $(c_flags) -S -o $@ $<

 %.s: %.c FORCE
 	$(call cmd,cmd_cc_s_c)

 quiet_cmd_cc_i_c = CPP    $(RELDIR)/$@
 cmd_cc_i_c       = $(CPP) $(c_flags)   -o $@ $<

 %.i: %.c FORCE
 	$(call cmd,cmd_cc_i_c)

 quiet_cmd_cc_o_c = CC     $(RELDIR)/$@
 cmd_cc_o_c       = $(CC) -Wp,-MD,.$(subst /,_,$@).d $(c_flags) -c -o $@ $<

 %.o: %.c FORCE
 	$(call if_changed_dep,cc_o_c)

 quiet_cmd_cc_lst_c = Generating $(RELDIR)/$@
 cmd_cc_lst_c     = $(CC) $(c_flags) -g -c -o $*.o $< && $(TOPDIR)/scripts/makelst $*.o $(TOPDIR)/System.map $(OBJDUMP) > $@

 %.lst: %.c FORCE
 	$(call cmd,cmd_cc_lst_c)

 # Compile assembler sources (.S)
 # ---------------------------------------------------------------------------

 # FIXME (s.a.)
 modkern_aflags := $(AFLAGS_KERNEL)

 $(real-objs-y)      : modkern_aflags := $(AFLAGS_KERNEL)
 $(real-objs-y:.o=.s): modkern_aflags := $(AFLAGS_KERNEL)

 $(real-objs-m)      : modkern_aflags := $(AFLAGS_MODULE)
 $(real-objs-m:.o=.s): modkern_aflags := $(AFLAGS_MODULE)

 a_flags = $(AFLAGS) $(NOSTDINC_FLAGS) $(modkern_aflags) $(EXTRA_AFLAGS) $(AFLAGS_$(*F).o)

 quiet_cmd_as_s_S = CPP    $(RELDIR)/$@
 cmd_as_s_S       = $(CPP) $(a_flags)   -o $@ $<

 %.s: %.S FORCE
 	$(call cmd,cmd_as_s_S)

 quiet_cmd_as_o_S = AS     $(RELDIR)/$@
 cmd_as_o_S       = $(CC) -Wp,-MD,.$(subst /,_,$@).d $(a_flags) -c -o $@ $<

 %.o: %.S FORCE
 	$(call if_changed_dep,as_o_S)

 # If a Makefile does define neither O_TARGET nor L_TARGET,
 # use a standard O_TARGET named "built-in.o"

 # Build the compiled-in targets
 # ---------------------------------------------------------------------------

 # To build objects in subdirs, we need to descend into the directories
 $(sort $(subdir-obj-y)): sub_dirs ;

 #
 # Rule to compile a set of .o files into one .o file
 #
 ifdef O_TARGET
 quiet_cmd_link_o_target = LD     $(RELDIR)/$@
 # If the list of objects to link is empty, just create an empty O_TARGET
 cmd_link_o_target = $(if $(strip $(obj-y)),\
 		      $(LD) $(EXTRA_LDFLAGS) -r -o $@ $(filter $(obj-y), $^),\
 		      rm -f $@; $(AR) rcs $@)

 $(O_TARGET): $(obj-y) FORCE
 	$(call if_changed,cmd_link_o_target)
 endif # O_TARGET

 #
 # Rule to compile a set of .o files into one .a file
 #
 ifdef L_TARGET
 quiet_cmd_link_l_target = AR     $(RELDIR)/$@
 cmd_link_l_target = rm -f $@; $(AR) $(EXTRA_ARFLAGS) rcs $@ $(obj-y)

 $(L_TARGET): $(obj-y) FORCE
 	$(call if_changed,cmd_link_l_target)
 endif

 #
 # Rule to link composite objects
 #

 quiet_cmd_link_multi = LD     $(RELDIR)/$@
 cmd_link_multi = $(LD) $(EXTRA_LDFLAGS) -r -o $@ $(filter $($(basename $@)-objs),$^)

 # We would rather have a list of rules like
 # 	foo.o: $(foo-objs)
 # but that's not so easy, so we rather make all composite objects depend
 # on the set of all their parts
 $(multi-used-y) : %.o: $(multi-objs-y) FORCE
 	$(call if_changed,cmd_link_multi)

 $(multi-used-m) : %.o: $(multi-objs-m) FORCE
 	$(call if_changed,cmd_link_multi)

 # Compile programs on the host
 # ===========================================================================

 host-progs-single     := $(foreach m,$(host-progs),$(if $($(m)-objs),,$(m)))
 host-progs-multi      := $(foreach m,$(host-progs),$(if $($(m)-objs),$(m)))
 host-progs-multi-objs := $(foreach m,$(host-progs-multi),$($(m)-objs))

 quiet_cmd_host_cc__c  = HOSTCC $(RELDIR)/$@
 cmd_host_cc__c        = $(HOSTCC) -Wp,-MD,.$(subst /,_,$@).d \
 			$(HOSTCFLAGS) $(HOST_EXTRACFLAGS) -o $@ $<

 $(host-progs-single): %: %.c FORCE
 	$(call if_changed_dep,host_cc__c)

 quiet_cmd_host_cc_o_c = HOSTCC $(RELDIR)/$@
 cmd_host_cc_o_c       = $(HOSTCC) -Wp,-MD,.$(subst /,_,$@).d \
 			$(HOSTCFLAGS) $(HOST_EXTRACFLAGS) -c -o $@ $<

 $(host-progs-multi-objs): %.o: %.c FORCE
 	$(call if_changed_dep,host_cc_o_c)

 quiet_cmd_host_cc__o  = HOSTLD $(RELDIR)/$@
 cmd_host_cc__o        = $(HOSTCC) $(HOSTLDFLAGS) -o $@ $($@-objs) \
 			$(HOST_LOADLIBES)

 $(host-progs-multi): %: $(host-progs-multi-objs) FORCE
 	$(call if_changed,cmd_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
 # ---------------------------------------------------------------------------

 subdir-list := $(addprefix _subdir_,$(subdir-ym))

 .PHONY: sub_dirs $(subdir-list)

 sub_dirs: $(subdir-list)

 $(subdir-list):
 	@$(MAKE) -C $(patsubst _subdir_%,%,$@)

 # Descending and 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

 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
 # ---------------------------------------------------------------------------

 .PHONY: FORCE

 FORCE:

 #
 # This is useful for testing
 # FIXME: really?
 script:
 	$(SCRIPT)

 #
 # This sets version suffixes on exported symbols
 # Separate the object into "normal" objects and "exporting" objects
 # 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

 # Usage:
 # normally one uses rules like
 #
 # %.o: %.c
 # 	<command line>
 #
 # However, these only rebuild the target when the source has changed,
 # but not when e.g. the command or the flags on the command line changed.
 #
 # This extension allows to do the following:
 #
 # command = <command line>
 #
 # %.o: %.c dummy
 #	$(call if_changed,command)
 #
 # which will make sure to rebuild the target when either its prerequisites
 # change or the command line changes
 #
 # The magic works as follows:
 # The addition of dummy to the dependencies causes the rule for rebuilding
 # to be always executed. However, the if_changed function will generate
 # an empty command when
 # o none of the prequesites changed (i.e $? is empty)
 # o the command line did not change (we compare the old command line,
 #   which is saved in .<target>.o, to the current command line using
 #   the two filter-out commands)

 # read all saved command lines and dependencies

 cmd_files := $(wildcard .*.cmd)
 ifneq ($(cmd_files),)
   include $(cmd_files)
 endif

 # function to only execute the passed command if necessary

 if_changed = $(if $(strip $? \
 		          $(filter-out $($(1)),$(cmd_$(@F)))\
 			  $(filter-out $(cmd_$(@F)),$($(1)))),\
 	       @$(if $($(quiet)$(1)),echo '  $($(quiet)$(1))' &&) $($(1)) && echo 'cmd_$@ := $($(1))' > $(@D)/.$(@F).cmd)


 # execute the command and also postprocess generated .d dependencies
 # file

 if_changed_dep = $(if $(strip $? \
 		          $(filter-out $(cmd_$(1)),$(cmd_$@))\
 			  $(filter-out $(cmd_$@),$(cmd_$(1)))),\
 	@set -e; \
 	$(if $($(quiet)cmd_$(1)),echo '  $($(quiet)cmd_$(1))';) \
 	$(cmd_$(1)); \
 	$(TOPDIR)/scripts/fixdep $(subst /,_,$@) $(TOPDIR) '$(cmd_$(1))' > .$(subst /,_,$@).tmp; \
 	rm -f .$(subst /,_,$@).d; \
 	mv -f .$(subst /,_,$@).tmp .$(subst /,_,$@).cmd )

 # If quiet is set, only print short version of command

 cmd = @$(if $($(quiet)$(1)),echo '  $($(quiet)$(1))' &&) $($(1))
	#
	# This file contains rules which are shared between multiple Makefiles.
	#

	# Some standard vars

	comma := ,
	empty :=
	space := $(empty) $(empty)

	# Figure out paths
	# ---------------------------------------------------------------------------
	# Find the path relative to the toplevel dir, $(RELDIR), and express
	# the toplevel dir as a relative path from this dir, $(TOPDIR_REL)

	ifeq ($(findstring $(TOPDIR),$(CURDIR)),)
	# Can only happen when something is built out of tree
	RELDIR := $(CURDIR)
	TOPDIR_REL := $(TOPDIR)
	else
	RELDIR := $(subst $(TOPDIR)/,,$(CURDIR))
	TOPDIR_REL := $(subst $(space),,$(foreach d,$(subst /, ,$(RELDIR)),../))
	endif

	# Figure out what we need to build from the various variables
	# ===========================================================================

	# When an object is listed to be built compiled-in and modular,
	# only build the compiled-in version

	obj-m := $(filter-out $(obj-y),$(obj-m))

	# Handle objects in subdirs
	# ---------------------------------------------------------------------------
	# o if we encounter foo/ in $(obj-y), replace it by foo/built-in.o
	# and add the directory to the list of dirs to descend into: $(subdir-y)
	# o if we encounter foo/ in $(obj-m), remove it from $(obj-m)
	# and add the directory to the list of dirs to descend into: $(subdir-m)

	__subdir-y := $(patsubst %/,%,$(filter %/, $(obj-y)))
	subdir-y += $(__subdir-y)
	__subdir-m := $(patsubst %/,%,$(filter %/, $(obj-m)))
	subdir-m += $(__subdir-m)
	__subdir-n := $(patsubst %/,%,$(filter %/, $(obj-n)))
	subdir-n += $(__subdir-n)
	__subdir- := $(patsubst %/,%,$(filter %/, $(obj-)))
	subdir- += $(__subdir-)
	obj-y := $(patsubst %/, %/built-in.o, $(obj-y))
	obj-m := $(filter-out %/, $(obj-m))

	# If a dir is selected in $(subdir-y) and also mentioned in $(mod-subdirs),
	# add it to $(subdir-m)

	both-m := $(filter $(mod-subdirs), $(subdir-y))
	subdir-ym := $(sort $(subdir-y) $(subdir-m))
	subdir-ymn := $(sort $(subdir-ym) $(subdir-n) $(subdir-))

	# export.o is never a composite object, since $(export-objs) has a
	# fixed meaning (== objects which EXPORT_SYMBOL())
	__obj-y = $(filter-out export.o,$(obj-y))
	__obj-m = $(filter-out export.o,$(obj-m))

	# if $(foo-objs) exists, foo.o is a composite object
	__multi-used-y := $(sort $(foreach m,$(__obj-y), $(if $($(m:.o=-objs)), $(m))))
	__multi-used-m := $(sort $(foreach m,$(__obj-m), $(if $($(m:.o=-objs)), $(m))))

	# FIXME: Rip this out later
	# Backwards compatibility: if a composite object is listed in
	# $(list-multi), skip it here, since the Makefile will have an explicit
	# link rule for it

	multi-used-y := $(filter-out $(list-multi),$(__multi-used-y))
	multi-used-m := $(filter-out $(list-multi),$(__multi-used-m))

	# Build list of the parts of our composite objects, our composite
	# objects depend on those (obviously)
	multi-objs-y := $(foreach m, $(multi-used-y), $($(m:.o=-objs)))
	multi-objs-m := $(foreach m, $(multi-used-m), $($(m:.o=-objs)))

	# $(subdir-obj-y) is the list of objects in $(obj-y) which do not live
	# in the local directory
	subdir-obj-y := $(foreach o,$(obj-y),$(if $(filter-out $(o),$(notdir $(o))),$(o)))

	# Replace multi-part objects by their individual parts, look at local dir only
	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.
	# ==========================================================================

	ifndef O_TARGET
	ifndef L_TARGET
	O_TARGET := built-in.o
	endif
	endif

	# The echo suppresses the "Nothing to be done for first_rule"
	first_rule: $(if $(KBUILD_BUILTIN),$(O_TARGET) $(L_TARGET) $(EXTRA_TARGETS)) \
	$(if $(KBUILD_MODULES),$(obj-m)) \
	sub_dirs
	@echo -n

	# Compile C sources (.c)
	# ---------------------------------------------------------------------------

	# If we don't know if built-in or modular, assume built-in.
	# Only happens in Makefiles which override the default first_rule:
	modkern_cflags := $(CFLAGS_KERNEL)

	$(real-objs-y) : modkern_cflags := $(CFLAGS_KERNEL)
	$(real-objs-y:.o=.i) : modkern_cflags := $(CFLAGS_KERNEL)
	$(real-objs-y:.o=.s) : modkern_cflags := $(CFLAGS_KERNEL)
	$(real-objs-y:.o=.lst): modkern_cflags := $(CFLAGS_KERNEL)

	$(real-objs-m) : modkern_cflags := $(CFLAGS_MODULE)
	$(real-objs-m:.o=.i) : modkern_cflags := $(CFLAGS_MODULE)
	$(real-objs-m:.o=.lst): modkern_cflags := $(CFLAGS_MODULE)

	$(export-objs) : export_flags := $(EXPORT_FLAGS)
	$(export-objs:.o=.i) : export_flags := $(EXPORT_FLAGS)
	$(export-objs:.o=.s) : export_flags := $(EXPORT_FLAGS)
	$(export-objs:.o=.lst): export_flags := $(EXPORT_FLAGS)

	c_flags = $(CFLAGS) $(NOSTDINC_FLAGS) $(modkern_cflags) $(EXTRA_CFLAGS) $(CFLAGS_$(F).o) -DKBUILD_BASENAME=$(subst $(comma),_,$(subst -,_,$(F))) $(export_flags)

	quiet_cmd_cc_s_c = CC $(RELDIR)/$@
	cmd_cc_s_c = $(CC) $(c_flags) -S -o $@ $<

	%.s: %.c FORCE
	$(call cmd,cmd_cc_s_c)

	quiet_cmd_cc_i_c = CPP $(RELDIR)/$@
	cmd_cc_i_c = $(CPP) $(c_flags) -o $@ $<

	%.i: %.c FORCE
	$(call cmd,cmd_cc_i_c)

	quiet_cmd_cc_o_c = CC $(RELDIR)/$@
	cmd_cc_o_c = $(CC) -Wp,-MD,.$(subst /,_,$@).d $(c_flags) -c -o $@ $<

	%.o: %.c FORCE
	$(call if_changed_dep,cc_o_c)

	quiet_cmd_cc_lst_c = Generating $(RELDIR)/$@
	cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $.o $< && $(TOPDIR)/scripts/makelst $.o $(TOPDIR)/System.map $(OBJDUMP) > $@

	%.lst: %.c FORCE
	$(call cmd,cmd_cc_lst_c)

	# Compile assembler sources (.S)
	# ---------------------------------------------------------------------------

	# FIXME (s.a.)
	modkern_aflags := $(AFLAGS_KERNEL)

	$(real-objs-y) : modkern_aflags := $(AFLAGS_KERNEL)
	$(real-objs-y:.o=.s): modkern_aflags := $(AFLAGS_KERNEL)

	$(real-objs-m) : modkern_aflags := $(AFLAGS_MODULE)
	$(real-objs-m:.o=.s): modkern_aflags := $(AFLAGS_MODULE)

	a_flags = $(AFLAGS) $(NOSTDINC_FLAGS) $(modkern_aflags) $(EXTRA_AFLAGS) $(AFLAGS_$(*F).o)

	quiet_cmd_as_s_S = CPP $(RELDIR)/$@
	cmd_as_s_S = $(CPP) $(a_flags) -o $@ $<

	%.s: %.S FORCE
	$(call cmd,cmd_as_s_S)

	quiet_cmd_as_o_S = AS $(RELDIR)/$@
	cmd_as_o_S = $(CC) -Wp,-MD,.$(subst /,_,$@).d $(a_flags) -c -o $@ $<

	%.o: %.S FORCE
	$(call if_changed_dep,as_o_S)

	# If a Makefile does define neither O_TARGET nor L_TARGET,
	# use a standard O_TARGET named "built-in.o"

	# Build the compiled-in targets
	# ---------------------------------------------------------------------------

	# To build objects in subdirs, we need to descend into the directories
	$(sort $(subdir-obj-y)): sub_dirs ;

	#
	# Rule to compile a set of .o files into one .o file
	#
	ifdef O_TARGET
	quiet_cmd_link_o_target = LD $(RELDIR)/$@
	# If the list of objects to link is empty, just create an empty O_TARGET
	cmd_link_o_target = $(if $(strip $(obj-y)),\
	$(LD) $(EXTRA_LDFLAGS) -r -o $@ $(filter $(obj-y), $^),\
	rm -f $@; $(AR) rcs $@)

	$(O_TARGET): $(obj-y) FORCE
	$(call if_changed,cmd_link_o_target)
	endif # O_TARGET

	#
	# Rule to compile a set of .o files into one .a file
	#
	ifdef L_TARGET
	quiet_cmd_link_l_target = AR $(RELDIR)/$@
	cmd_link_l_target = rm -f $@; $(AR) $(EXTRA_ARFLAGS) rcs $@ $(obj-y)

	$(L_TARGET): $(obj-y) FORCE
	$(call if_changed,cmd_link_l_target)
	endif

	#
	# Rule to link composite objects
	#

	quiet_cmd_link_multi = LD $(RELDIR)/$@
	cmd_link_multi = $(LD) $(EXTRA_LDFLAGS) -r -o $@ $(filter $($(basename $@)-objs),$^)

	# We would rather have a list of rules like
	# foo.o: $(foo-objs)
	# but that's not so easy, so we rather make all composite objects depend
	# on the set of all their parts
	$(multi-used-y) : %.o: $(multi-objs-y) FORCE
	$(call if_changed,cmd_link_multi)

	$(multi-used-m) : %.o: $(multi-objs-m) FORCE
	$(call if_changed,cmd_link_multi)

	# Compile programs on the host
	# ===========================================================================

	host-progs-single := $(foreach m,$(host-progs),$(if $($(m)-objs),,$(m)))
	host-progs-multi := $(foreach m,$(host-progs),$(if $($(m)-objs),$(m)))
	host-progs-multi-objs := $(foreach m,$(host-progs-multi),$($(m)-objs))

	quiet_cmd_host_cc__c = HOSTCC $(RELDIR)/$@
	cmd_host_cc__c = $(HOSTCC) -Wp,-MD,.$(subst /,_,$@).d \
	$(HOSTCFLAGS) $(HOST_EXTRACFLAGS) -o $@ $<

	$(host-progs-single): %: %.c FORCE
	$(call if_changed_dep,host_cc__c)

	quiet_cmd_host_cc_o_c = HOSTCC $(RELDIR)/$@
	cmd_host_cc_o_c = $(HOSTCC) -Wp,-MD,.$(subst /,_,$@).d \
	$(HOSTCFLAGS) $(HOST_EXTRACFLAGS) -c -o $@ $<

	$(host-progs-multi-objs): %.o: %.c FORCE
	$(call if_changed_dep,host_cc_o_c)

	quiet_cmd_host_cc__o = HOSTLD $(RELDIR)/$@
	cmd_host_cc__o = $(HOSTCC) $(HOSTLDFLAGS) -o $@ $($@-objs) \
	$(HOST_LOADLIBES)

	$(host-progs-multi): %: $(host-progs-multi-objs) FORCE
	$(call if_changed,cmd_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
	# ---------------------------------------------------------------------------

	subdir-list := $(addprefix _subdir_,$(subdir-ym))

	.PHONY: sub_dirs $(subdir-list)

	sub_dirs: $(subdir-list)

	$(subdir-list):
	@$(MAKE) -C $(patsubst _subdir_%,%,$@)

	# Descending and 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

	# Add FORCE to the prequisites of a target to force it to be always rebuilt.
	# ---------------------------------------------------------------------------

	.PHONY: FORCE

	FORCE:

	#
	# This is useful for testing
	# FIXME: really?
	script:
	$(SCRIPT)

	#
	# This sets version suffixes on exported symbols
	# Separate the object into "normal" objects and "exporting" objects
	# 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

	# Usage:
	# normally one uses rules like
	#
	# %.o: %.c
	# <command line>
	#
	# However, these only rebuild the target when the source has changed,
	# but not when e.g. the command or the flags on the command line changed.
	#
	# This extension allows to do the following:
	#
	# command = <command line>
	#
	# %.o: %.c dummy
	# $(call if_changed,command)
	#
	# which will make sure to rebuild the target when either its prerequisites
	# change or the command line changes
	#
	# The magic works as follows:
	# The addition of dummy to the dependencies causes the rule for rebuilding
	# to be always executed. However, the if_changed function will generate
	# an empty command when
	# o none of the prequesites changed (i.e $? is empty)
	# o the command line did not change (we compare the old command line,
	# which is saved in .<target>.o, to the current command line using
	# the two filter-out commands)

	# read all saved command lines and dependencies

	cmd_files := $(wildcard .*.cmd)
	ifneq ($(cmd_files),)
	include $(cmd_files)
	endif

	# function to only execute the passed command if necessary

	if_changed = $(if $(strip $? \
	$(filter-out $($(1)),$(cmd_$(@F)))\
	$(filter-out $(cmd_$(@F)),$($(1)))),\
	@$(if $($(quiet)$(1)),echo ' $($(quiet)$(1))' &&) $($(1)) && echo 'cmd_$@ := $($(1))' > $(@D)/.$(@F).cmd)


	# execute the command and also postprocess generated .d dependencies
	# file

	if_changed_dep = $(if $(strip $? \
	$(filter-out $(cmd_$(1)),$(cmd_$@))\
	$(filter-out $(cmd_$@),$(cmd_$(1)))),\
	@set -e; \
	$(if $($(quiet)cmd_$(1)),echo ' $($(quiet)cmd_$(1))';) \
	$(cmd_$(1)); \
	$(TOPDIR)/scripts/fixdep $(subst /,_,$@) $(TOPDIR) '$(cmd_$(1))' > .$(subst /,_,$@).tmp; \
	rm -f .$(subst /,_,$@).d; \
	mv -f .$(subst /,_,$@).tmp .$(subst /,_,$@).cmd )

	# If quiet is set, only print short version of command

	cmd = @$(if $($(quiet)$(1)),echo ' $($(quiet)$(1))' &&) $($(1))