#
# 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

# Some paths for the Makefiles to use
# ---------------------------------------------------------------------------

# Usage:
#
# $(obj)/target.o                     : target.o in the build dir
# $(src)/target.c                     : target.c in the source dir
# $(objtree)/include/linux/version.h  : Some file relative to the build
#					dir root
# $(srctree)/include/linux/module.h   : Some file relative to the source
#				        dir root
#
# Those can only be used in the section after
# include $(TOPDIR)/Rules.make, i.e for generated files and the like.
# Intentionally.
#
# We don't support separate source / object yet, so these are just
# placeholders for now

obj := .
src := .
objtree := $(TOPDIR)
srctree := $(TOPDIR)

# 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))

# Subdirectories we need to descend into

subdir-ym	:= $(sort $(subdir-y) $(subdir-m))

# 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)))

# Only build module versions for files which are selected to be built
export-objs := $(filter $(export-objs),$(real-objs-y) $(real-objs-m))

# The temporary file to save gcc -MD generated dependencies must not
# contain a comma
depfile = $(subst $(comma),_,$(@D)/.$(@F).d)

# 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
# ===========================================================================

ifeq ($(strip $(export-objs)),)

# If we don't export any symbols in this dir, just descend
# ---------------------------------------------------------------------------

fastdep: sub_dirs
	@echo -n

else

# This sets version suffixes on exported symbols
# ---------------------------------------------------------------------------

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

#	Don't include modversions.h, we're just about to generate it here.

CFLAGS_MODULE := $(filter-out -include $(HPATH)/linux/modversions.h,$(CFLAGS_MODULE))

$(addprefix $(MODVERDIR)/,$(real-objs-y:.o=.ver)): modkern_cflags := $(CFLAGS_KERNEL)
$(addprefix $(MODVERDIR)/,$(real-objs-m:.o=.ver)): modkern_cflags := $(CFLAGS_MODULE)
$(addprefix $(MODVERDIR)/,$(export-objs:.o=.ver)): export_flags   := -D__GENKSYMS__

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

# Our objects only depend on modversions.h, not on the individual .ver
# files (fix-dep filters them), so touch modversions.h if any of the .ver
# files changes

quiet_cmd_cc_ver_c = MKVER  include/linux/modules/$(RELDIR)/$*.ver
cmd_cc_ver_c = $(CPP) $(c_flags) $< | $(GENKSYMS) $(genksyms_smp_prefix) \
		 -k $(VERSION).$(PATCHLEVEL).$(SUBLEVEL) > $@.tmp

# Okay, let's explain what's happening in rule_make_cc_ver_c:
# o echo the command
# o execute the command
# o If the $(CPP) fails, we won't notice because it's output is piped
#   to $(GENKSYMS) which does not fail. We recognize this case by
#   looking if the generated $(depfile) exists, though.
# o If the .ver file changed, touch modversions.h, which is our maker
#   of any changed .ver files.
# o Move command line and deps into their normal .*.cmd place.  

define rule_cc_ver_c
	$(if $($(quiet)cmd_cc_ver_c),echo '  $($(quiet)cmd_cc_ver_c)';) \
	$(cmd_cc_ver_c); \
	if [ ! -r $(depfile) ]; then exit 1; fi; \
	$(TOPDIR)/scripts/fixdep $(depfile) $@ $(TOPDIR) '$(cmd_cc_ver_c)' > $(@D)/.$(@F).tmp; \
	rm -f $(depfile); \
	if [ ! -r $@ ] || cmp -s $@ $@.tmp; then \
	  touch $(TOPDIR)/include/linux/modversions.h; \
	fi; \
	mv -f $@.tmp $@
	mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd
endef

$(MODVERDIR)/%.ver: %.c FORCE
	@$(call if_changed_rule,cc_ver_c)

targets := $(addprefix $(MODVERDIR)/,$(export-objs:.o=.ver))

fastdep: $(targets) sub_dirs
	@mkdir -p $(TOPDIR)/.tmp_export-objs/modules/$(RELDIR)
	@touch $(addprefix $(TOPDIR)/.tmp_export-objs/modules/$(RELDIR)/,$(export-objs:.o=.ver))

endif # export-objs 

else # ! fastdep
ifeq ($(MAKECMDGOALS),modules_install)

# ==========================================================================
# Installing modules
# ==========================================================================

.PHONY: modules_install

modules_install: sub_dirs
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

else # ! modules_install

# ==========================================================================
# Building
# ==========================================================================

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

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)
# ---------------------------------------------------------------------------

# Default is built-in, unless we know otherwise
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 = -Wp,-MD,$(depfile) $(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 if_changed_dep,cc_s_c)

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

%.i: %.c FORCE
	$(call if_changed_dep,cc_i_c)

quiet_cmd_cc_o_c = CC     $(RELDIR)/$@
cmd_cc_o_c       = $(CC) $(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 if_changed_dep,cc_lst_c)

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

modkern_aflags := $(AFLAGS_KERNEL)

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

a_flags = -Wp,-MD,$(depfile) $(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 if_changed_dep,as_s_S)

quiet_cmd_as_o_S = AS     $(RELDIR)/$@
cmd_as_o_S       = $(CC) $(a_flags) -c -o $@ $<

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

targets += $(real-objs-y) $(real-objs-m) $(EXTRA_TARGETS) $(MAKECMDGOALS)

# 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,link_o_target)

targets += $(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,link_l_target)

targets += $(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,link_multi)

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

targets += $(multi-used-y) $(multi-used-m)

# 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) \
			$(HOST_LOADLIBES) -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,host_cc__o)

targets += $(host-progs-single) $(host-progs-multi-objs) $(host-progs-multi) 

endif # ! modules_install
endif # ! fastdep

# Shipped files
# ===========================================================================

%:: %_shipped
	@echo '  CP     $(RELDIR)/$@'
	@cp $< $@

# ===========================================================================
# Generic stuff
# ===========================================================================

# Descending
# ---------------------------------------------------------------------------

.PHONY: sub_dirs $(subdir-ym)

sub_dirs: $(subdir-ym)

$(subdir-ym):
	@$(MAKE) -C $@ $(MAKECMDGOALS)

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

.PHONY: FORCE

FORCE:

#
# 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
#

# ---------------------------------------------------------------------------
# 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 for the $(targets) we
# may be building above, using $(if_changed{,_dep}). As an
# optimization, we don't need to read them if the target does not
# exist, we will rebuild anyway in that case.

targets := $(wildcard $(sort $(targets)))
cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))

ifneq ($(cmd_files),)
  include $(cmd_files)
endif

# function to only execute the passed command if necessary

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


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

if_changed_dep = $(if $(strip $? $(filter-out FORCE $(wildcard $^),$^)\
		          $(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 $(depfile) $@ $(TOPDIR) '$(cmd_$(1))' > $(@D)/.$(@F).tmp; \
	rm -f $(depfile); \
	mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd)

# Usage: $(call if_changed_rule,foo)
# will check if $(cmd_foo) changed, or any of the prequisites changed,
# and if so will execute $(rule_foo)

if_changed_rule = $(if $(strip $? \
		               $(filter-out $(cmd_$(1)),$(cmd_$@))\
			       $(filter-out $(cmd_$@),$(cmd_$(1)))),\
			@set -e; \
			mkdir -p $(dir $@); \
			$(rule_$(1)))

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

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