kbuild: introduce Kbuild.include

Kbuild.include is a placeholder for definitions originally present in
both the top-level Makefile and scripts/Makefile.build.
There were a slight difference in the filechk definition, so the most videly
used version was kept and usr/Makefile was adopted for this syntax.

Signed-off-by: Sam Ravnborg <[e-mail]>
---

Makefile

···
 # Look for make include files relative to root of kernel src
 MAKEFLAGS += --include-dir=$(srctree)
 
+# We need some generic definitions
+include scripts/Kbuild.include
+
 # For maximum performance (+ possibly random breakage, uncomment
 # the following)
 
···
 # tree rather than in the kernel tree. The kernel tree might
 # even be read-only.
 export MODVERDIR := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_versions
-
-# The temporary file to save gcc -MD generated dependencies must not
-# contain a comma
-comma := ,
-depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
 
 # Files to ignore in find ... statements
 
···
   $(cmd_files): ;	# Do not try to update included dependency files
   include $(cmd_files)
 endif
-
-# Execute command and generate cmd file
-if_changed = $(if $(strip $? \
-		          $(filter-out $(cmd_$(1)),$(cmd_$@))\
-			  $(filter-out $(cmd_$@),$(cmd_$(1)))),\
-	@set -e; \
-	$(if $($(quiet)cmd_$(1)),echo '  $(subst ','\'',$($(quiet)cmd_$(1)))';) \
-	$(cmd_$(1)); \
-	echo 'cmd_$@ := $(subst $$,$$$$,$(subst ','\'',$(cmd_$(1))))' > $(@D)/.$(@F).cmd)
-
-
-# execute the command and also postprocess generated .d dependencies
-# file
-if_changed_dep = $(if $(strip $? $(filter-out FORCE $(wildcard $^),$^)\
-		          $(filter-out $(cmd_$(1)),$(cmd_$@))\
-			  $(filter-out $(cmd_$@),$(cmd_$(1)))),\
-	$(Q)set -e; \
-	$(if $($(quiet)cmd_$(1)),echo '  $(subst ','\'',$($(quiet)cmd_$(1)))';) \
-	$(cmd_$(1)); \
-	scripts/basic/fixdep $(depfile) $@ '$(subst $$,$$$$,$(subst ','\'',$(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)),$(cmd_$(@F)))\
-			       $(filter-out $(cmd_$(@F)),$(cmd_$(1)))),\
-	               $(Q)$(rule_$(1)))
-
-# If quiet is set, only print short version of command
-
-cmd = @$(if $($(quiet)cmd_$(1)),echo '  $($(quiet)cmd_$(1))' &&) $(cmd_$(1))
-
-# filechk is used to check if the content of a generated file is updated.
-# Sample usage:
-# define filechk_sample
-#	echo $KERNELRELEASE
-# endef
-# version.h : Makefile
-#	$(call filechk,sample)
-# The rule defined shall write to stdout the content of the new file.
-# The existing file will be compared with the new one.
-# - If no file exist it is created
-# - If the content differ the new file is used
-# - If they are equal no change, and no timestamp update
-
-define filechk
-	@set -e;				\
-	echo '  CHK     $@';			\
-	mkdir -p $(dir $@);			\
-	$(filechk_$(1)) < $< > $@.tmp;		\
-	if [ -r $@ ] && cmp -s $@ $@.tmp; then	\
-		rm -f $@.tmp;			\
-	else					\
-		echo '  UPD     $@';		\
-		mv -f $@.tmp $@;		\
-	fi
-endef
-
-# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=dir
-# Usage:
-# $(Q)$(MAKE) $(build)=dir
-build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
 
 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=dir
 # Usage:

scripts/Kbuild.include

···
+####
+# kbuild: Generic definitions
+
+# Convinient variables
+comma   := ,
+empty   :=
+space   := $(empty) $(empty)
+
+###
+# The temporary file to save gcc -MD generated dependencies must not
+# contain a comma
+depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
+
+###
+# filechk is used to check if the content of a generated file is updated.
+# Sample usage:
+# define filechk_sample
+#	echo $KERNELRELEASE
+# endef
+# version.h : Makefile
+#	$(call filechk,sample)
+# The rule defined shall write to stdout the content of the new file.
+# The existing file will be compared with the new one.
+# - If no file exist it is created
+# - If the content differ the new file is used
+# - If they are equal no change, and no timestamp update
+# - stdin is piped in from the first prerequisite ($<) so one has
+#   to specify a valid file as first prerequisite (often the kbuild file)
+define filechk
+	$(Q)set -e;				\
+	echo '  CHK     $@';			\
+	mkdir -p $(dir $@);			\
+	$(filechk_$(1)) < $< > $@.tmp;		\
+	if [ -r $@ ] && cmp -s $@ $@.tmp; then	\
+		rm -f $@.tmp;			\
+	else					\
+		echo '  UPD     $@';		\
+		mv -f $@.tmp $@;		\
+	fi
+endef
+
+###
+# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
+# Usage:
+# $(Q)$(MAKE) $(build)=dir
+build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
+
+# If quiet is set, only print short version of command
+cmd = @$(if $($(quiet)cmd_$(1)),\
+      echo '  $(subst ','\'',$($(quiet)cmd_$(1)))' &&) $(cmd_$(1))
+
+###
+# if_changed      - execute command if any prerequisite is newer than 
+#                   target, or command line has changed
+# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
+#                   including used config symbols
+# if_changed_rule - as if_changed but execute rule instead
+# See Documentation/kbuild/makefiles.txt for more info
+
+ifneq ($(KBUILD_NOCMDDEP),1)
+# Check if both arguments has same arguments. Result in empty string if equal
+# User may override this check using make KBUILD_NOCMDDEP=1
+arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) )
+endif
+
+# echo command. Short version is $(quiet) equals quiet, otherwise full command
+echo-cmd = $(if $($(quiet)cmd_$(1)), \
+	echo '  $(subst ','\'',$($(quiet)cmd_$(1)))';)
+
+# function to only execute the passed command if necessary
+# >'< substitution is for echo to work, >$< substitution to preserve $ when reloading .cmd file
+# note: when using inline perl scripts [perl -e '...$$t=1;...'] in $(cmd_xxx) double $$ your perl vars
+# 
+if_changed = $(if $(strip $? $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \
+	@set -e; \
+	$(echo-cmd) \
+	$(cmd_$(1)); \
+	echo 'cmd_$@ := $(subst $$,$$$$,$(subst ','\'',$(cmd_$(1))))' > $(@D)/.$(@F).cmd)
+
+# execute the command and also postprocess generated .d dependencies
+# file
+if_changed_dep = $(if $(strip $? $(filter-out FORCE $(wildcard $^),$^)\
+	$(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),                  \
+	@set -e; \
+	$(echo-cmd) \
+	$(cmd_$(1)); \
+	scripts/basic/fixdep $(depfile) $@ '$(subst $$,$$$$,$(subst ','\'',$(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 $? $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),\
+			@set -e; \
+			$(rule_$(1)))

scripts/Makefile.build

···
 
 include $(if $(wildcard $(obj)/Kbuild), $(obj)/Kbuild, $(obj)/Makefile)
 
+include scripts/Kbuild.include
 include scripts/Makefile.lib
 
 ifdef host-progs

scripts/Makefile.lib

···
-# ===========================================================================
-# kbuild: Generic definitions
-# ===========================================================================
-
-# Standard vars
-
-comma   := ,
-empty   :=
-space   := $(empty) $(empty)
-
 # Backward compatibility - to be removed...
 extra-y	+= $(EXTRA_TARGETS)
 # Figure out what we need to build from the various variables
···
 multi-objs-m	:= $(addprefix $(obj)/,$(multi-objs-m))
 subdir-ym	:= $(addprefix $(obj)/,$(subdir-ym))
 obj-dirs	:= $(addprefix $(obj)/,$(obj-dirs))
-
-# The temporary file to save gcc -MD generated dependencies must not
-# contain a comma
-depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
 
 # These flags are needed for modversions and compiling, so we define them here
 # already
···
 quiet_cmd_gzip = GZIP    $@
 cmd_gzip = gzip -f -9 < $< > $@
 
-# ===========================================================================
-# Generic stuff
-# ===========================================================================
-
-ifneq ($(KBUILD_NOCMDDEP),1)
-# Check if both arguments has same arguments. Result in empty string if equal
-# User may override this check using make KBUILD_NOCMDDEP=1
-arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) )
-
-endif
-
-# echo command. Short version is $(quiet) equals quiet, otherwise full command
-echo-cmd = $(if $($(quiet)cmd_$(1)), \
-	echo '  $(subst ','\'',$($(quiet)cmd_$(1)))';)
-
-# function to only execute the passed command if necessary
-# >'< substitution is for echo to work, >$< substitution to preserve $ when reloading .cmd file
-# note: when using inline perl scripts [perl -e '...$$t=1;...'] in $(cmd_xxx) double $$ your perl vars
-# 
-if_changed = $(if $(strip $? $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \
-	@set -e; \
-	$(echo-cmd) \
-	$(cmd_$(1)); \
-	echo 'cmd_$@ := $(subst $$,$$$$,$(subst ','\'',$(cmd_$(1))))' > $(@D)/.$(@F).cmd)
-
-
-# execute the command and also postprocess generated .d dependencies
-# file
-
-if_changed_dep = $(if $(strip $? $(filter-out FORCE $(wildcard $^),$^)\
-	$(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),                  \
-	@set -e; \
-	$(echo-cmd) \
-	$(cmd_$(1)); \
-	scripts/basic/fixdep $(depfile) $@ '$(subst $$,$$$$,$(subst ','\'',$(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 $? $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),\
-			@set -e; \
-			$(rule_$(1)))
-
-# If quiet is set, only print short version of command
-
-cmd = @$(if $($(quiet)cmd_$(1)),echo '  $(subst ','\'',$($(quiet)cmd_$(1)))' &&) $(cmd_$(1))
-
-# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
-# Usage:
-# $(Q)$(MAKE) $(build)=dir
-build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
-
-# filechk is used to check if the content of a generated file is updated.
-# Sample usage:
-# define filechk_sample
-#	echo $KERNELRELEASE
-# endef
-# version.h : Makefile
-#	$(call filechk,sample)
-# The rule defined shall write to stdout the content of the new file.
-# The existing file will be compared with the new one.
-# - If no file exist it is created
-# - If the content differ the new file is used
-# - If they are equal no change, and no timestamp update
-
-define filechk
-	$(Q)set -e;				\
-	echo '  CHK     $@';			\
-	mkdir -p $(dir $@);			\
-	$(filechk_$(1)) $(2) > $@.tmp;		\
-	if [ -r $@ ] && cmp -s $@ $@.tmp; then	\
-		rm -f $@.tmp;			\
-	else					\
-		echo '  UPD     $@';		\
-		mv -f $@.tmp $@;		\
-	fi
-endef
 

scripts/Makefile.modinst

···
 .PHONY: __modinst
 __modinst:
 
-include scripts/Makefile.lib
+include scripts/Kbuild.include
 
 #
 

scripts/Makefile.modpost

···
 _modpost: __modpost
 
 include .config
+include scripts/Kbuild.include
 include scripts/Makefile.lib
 
 symverfile := $(objtree)/Module.symvers

usr/Makefile

···
 filechk_initramfs_list = $(CONFIG_SHELL) \
  $(srctree)/scripts/gen_initramfs_list.sh $(gen_initramfs_args) $(quotefixed_initramfs_source)
 
-$(obj)/initramfs_list: FORCE
+$(obj)/initramfs_list: $(obj)/Makefile FORCE
 	$(call filechk,initramfs_list)
 
 quiet_cmd_cpio = CPIO    $@