[PATCH v3 1/2] kbuild: add read-file macro

[PATCH v3 1/2] kbuild: add read-file macro

[Masahiro Yamada]

Since GNU Make 4.2, $(file ...) supports the read operater '<', which
is useful to read a file without forking a new process. No warning is
shown even if the input file is missing.

For older Make versions, it falls back to the cat command.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Tested-by: Alexander Lobakin <alexandr.lobakin@intel.com>
---

Changes in v3:
  - Check the MAKE_VERSION in an ad-hoc way

 Makefile                  |  2 +-
 scripts/Kbuild.include    | 14 ++++++++++++++
 scripts/Makefile.modfinal |  2 +-
 scripts/Makefile.modinst  |  2 +-
 4 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index 8801cac4d3d5..2dda1e9a717a 100644
--- a/Makefile
+++ b/Makefile
@@ -376,7 +376,7 @@ else # !mixed-build
 include $(srctree)/scripts/Kbuild.include
 
 # Read KERNELRELEASE from include/config/kernel.release (if it exists)
-KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
+KERNELRELEASE = $(call read-file, include/config/kernel.release)
 KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION)
 export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
 
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 5019bc1e38e4..abdc269a51da 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -10,6 +10,10 @@ empty   :=
 space   := $(empty) $(empty)
 space_escape := _-_SPACE_-_
 pound := \#
+define newline
+
+
+endef
 
 ###
 # Comparison macros.
@@ -61,6 +65,16 @@ stringify = $(squote)$(quote)$1$(quote)$(squote)
 kbuild-dir = $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
 kbuild-file = $(or $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Makefile)
 
+###
+# Read a file, replacing newlines with spaces
+#
+# Make 4.2 or later can read a file by using its builtin function.
+ifneq ($(filter-out 3.% 4.0 4.1, $(MAKE_VERSION)),)
+read-file = $(subst $(newline),$(space),$(file < $1))
+else
+read-file = $(shell cat $1 2>/dev/null)
+endif
+
 ###
 # Easy method for doing a status message
        kecho := :
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index 25bedd83644b..7252f6cf7837 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -13,7 +13,7 @@ include $(srctree)/scripts/Kbuild.include
 include $(srctree)/scripts/Makefile.lib
 
 # find all modules listed in modules.order
-modules := $(sort $(shell cat $(MODORDER)))
+modules := $(sort $(call read-file, $(MODORDER)))
 
 __modfinal: $(modules)
 	@:
diff --git a/scripts/Makefile.modinst b/scripts/Makefile.modinst
index a4c987c23750..509d424dbbd2 100644
--- a/scripts/Makefile.modinst
+++ b/scripts/Makefile.modinst
@@ -9,7 +9,7 @@ __modinst:
 include include/config/auto.conf
 include $(srctree)/scripts/Kbuild.include
 
-modules := $(sort $(shell cat $(MODORDER)))
+modules := $(sort $(call read-file, $(MODORDER)))
 
 ifeq ($(KBUILD_EXTMOD),)
 dst := $(MODLIB)/kernel
-- 
2.34.1

[PATCH v3 2/2] kconfig: refactor Makefile to reduce process forks

[Masahiro Yamada]

Refactor Makefile and use read-file macro. For Make >= 4.2, it can read
out a file by using the built-in function.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
---

Changes in v3:
 - Clean up *conf-cflags *conf-libs *conf-bin by "make mrproper"

 scripts/kconfig/.gitignore   |  4 +++-
 scripts/kconfig/Makefile     | 45 +++++++++++++++++++-----------------
 scripts/kconfig/gconf-cfg.sh |  7 ++++--
 scripts/kconfig/mconf-cfg.sh | 25 +++++++++++---------
 scripts/kconfig/nconf-cfg.sh | 23 ++++++++++--------
 scripts/kconfig/qconf-cfg.sh | 10 +++++---
 scripts/remove-stale-files   |  2 ++
 7 files changed, 68 insertions(+), 48 deletions(-)

diff --git a/scripts/kconfig/.gitignore b/scripts/kconfig/.gitignore
index 500e7424b3ef..c8a3f9cd52f0 100644
--- a/scripts/kconfig/.gitignore
+++ b/scripts/kconfig/.gitignore
@@ -1,5 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 /conf
 /[gmnq]conf
-/[gmnq]conf-cfg
+/[gmnq]conf-cflags
+/[gmnq]conf-libs
+/qconf-bin
 /qconf-moc.cc
diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index b8ef0fb4bbef..0b1d15efaeb0 100644
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -159,11 +159,12 @@ conf-objs	:= conf.o $(common-objs)
 hostprogs	+= nconf
 nconf-objs	:= nconf.o nconf.gui.o $(common-objs)
 
-HOSTLDLIBS_nconf	= $(shell . $(obj)/nconf-cfg && echo $$libs)
-HOSTCFLAGS_nconf.o	= $(shell . $(obj)/nconf-cfg && echo $$cflags)
-HOSTCFLAGS_nconf.gui.o	= $(shell . $(obj)/nconf-cfg && echo $$cflags)
+HOSTLDLIBS_nconf       = $(call read-file, $(obj)/nconf-libs)
+HOSTCFLAGS_nconf.o     = $(call read-file, $(obj)/nconf-cflags)
+HOSTCFLAGS_nconf.gui.o = $(call read-file, $(obj)/nconf-cflags)
 
-$(obj)/nconf.o $(obj)/nconf.gui.o: $(obj)/nconf-cfg
+$(obj)/nconf: | $(obj)/nconf-libs
+$(obj)/nconf.o $(obj)/nconf.gui.o: | $(obj)/nconf-cflags
 
 # mconf: Used for the menuconfig target based on lxdialog
 hostprogs	+= mconf
@@ -171,27 +172,28 @@ lxdialog	:= $(addprefix lxdialog/, \
 		     checklist.o inputbox.o menubox.o textbox.o util.o yesno.o)
 mconf-objs	:= mconf.o $(lxdialog) $(common-objs)
 
-HOSTLDLIBS_mconf = $(shell . $(obj)/mconf-cfg && echo $$libs)
+HOSTLDLIBS_mconf = $(call read-file, $(obj)/mconf-libs)
 $(foreach f, mconf.o $(lxdialog), \
-  $(eval HOSTCFLAGS_$f = $$(shell . $(obj)/mconf-cfg && echo $$$$cflags)))
+  $(eval HOSTCFLAGS_$f = $$(call read-file, $(obj)/mconf-cflags)))
 
-$(addprefix $(obj)/, mconf.o $(lxdialog)): $(obj)/mconf-cfg
+$(obj)/mconf: | $(obj)/mconf-libs
+$(addprefix $(obj)/, mconf.o $(lxdialog)): | $(obj)/mconf-cflags
 
 # qconf: Used for the xconfig target based on Qt
 hostprogs	+= qconf
 qconf-cxxobjs	:= qconf.o qconf-moc.o
 qconf-objs	:= images.o $(common-objs)
 
-HOSTLDLIBS_qconf	= $(shell . $(obj)/qconf-cfg && echo $$libs)
-HOSTCXXFLAGS_qconf.o	= $(shell . $(obj)/qconf-cfg && echo $$cflags)
-HOSTCXXFLAGS_qconf-moc.o = $(shell . $(obj)/qconf-cfg && echo $$cflags)
-
-$(obj)/qconf.o: $(obj)/qconf-cfg
+HOSTLDLIBS_qconf         = $(call read-file, $(obj)/qconf-libs)
+HOSTCXXFLAGS_qconf.o     = -std=c++11 -fPIC $(call read-file, $(obj)/qconf-cflags)
+HOSTCXXFLAGS_qconf-moc.o = -std=c++11 -fPIC $(call read-file, $(obj)/qconf-cflags)
+$(obj)/qconf: | $(obj)/qconf-libs
+$(obj)/qconf.o $(obj)/qconf-moc.o: | $(obj)/qconf-cflags
 
 quiet_cmd_moc = MOC     $@
-      cmd_moc = $(shell . $(obj)/qconf-cfg && echo $$moc) $< -o $@
+      cmd_moc = $(call read-file, $(obj)/qconf-bin)/moc $< -o $@
 
-$(obj)/qconf-moc.cc: $(src)/qconf.h $(obj)/qconf-cfg FORCE
+$(obj)/qconf-moc.cc: $(src)/qconf.h FORCE | $(obj)/qconf-bin
 	$(call if_changed,moc)
 
 targets += qconf-moc.cc
@@ -200,15 +202,16 @@ targets += qconf-moc.cc
 hostprogs	+= gconf
 gconf-objs	:= gconf.o images.o $(common-objs)
 
-HOSTLDLIBS_gconf    = $(shell . $(obj)/gconf-cfg && echo $$libs)
-HOSTCFLAGS_gconf.o  = $(shell . $(obj)/gconf-cfg && echo $$cflags)
+HOSTLDLIBS_gconf   = $(call read-file, $(obj)/gconf-libs)
+HOSTCFLAGS_gconf.o = $(call read-file, $(obj)/gconf-cflags)
 
-$(obj)/gconf.o: $(obj)/gconf-cfg
+$(obj)/gconf: | $(obj)/gconf-libs
+$(obj)/gconf.o: | $(obj)/gconf-cflags
 
 # check if necessary packages are available, and configure build flags
-filechk_conf_cfg = $(CONFIG_SHELL) $<
+cmd_conf_cfg = $< $(addprefix $(obj)/$*conf-, cflags libs bin)
 
-$(obj)/%conf-cfg: $(src)/%conf-cfg.sh FORCE
-	$(call filechk,conf_cfg)
+$(obj)/%conf-cflags $(obj)/%conf-libs $(obj)/%conf-bin: $(src)/%conf-cfg.sh
+	$(call cmd,conf_cfg)
 
-clean-files += *conf-cfg
+clean-files += *conf-cflags *conf-libs *conf-bin
diff --git a/scripts/kconfig/gconf-cfg.sh b/scripts/kconfig/gconf-cfg.sh
index cbd90c28c05f..040d8f338820 100755
--- a/scripts/kconfig/gconf-cfg.sh
+++ b/scripts/kconfig/gconf-cfg.sh
@@ -1,6 +1,9 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 
+cflags=$1
+libs=$2
+
 PKG="gtk+-2.0 gmodule-2.0 libglade-2.0"
 
 if [ -z "$(command -v ${HOSTPKG_CONFIG})" ]; then
@@ -26,5 +29,5 @@ if ! ${HOSTPKG_CONFIG} --atleast-version=2.0.0 gtk+-2.0; then
 	exit 1
 fi
 
-echo cflags=\"$(${HOSTPKG_CONFIG} --cflags $PKG)\"
-echo libs=\"$(${HOSTPKG_CONFIG} --libs $PKG)\"
+${HOSTPKG_CONFIG} --cflags ${PKG} > ${cflags}
+${HOSTPKG_CONFIG} --libs ${PKG} > ${libs}
diff --git a/scripts/kconfig/mconf-cfg.sh b/scripts/kconfig/mconf-cfg.sh
index 025b565e0b7c..1e61f50a5905 100755
--- a/scripts/kconfig/mconf-cfg.sh
+++ b/scripts/kconfig/mconf-cfg.sh
@@ -1,19 +1,22 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 
+cflags=$1
+libs=$2
+
 PKG="ncursesw"
 PKG2="ncurses"
 
 if [ -n "$(command -v ${HOSTPKG_CONFIG})" ]; then
 	if ${HOSTPKG_CONFIG} --exists $PKG; then
-		echo cflags=\"$(${HOSTPKG_CONFIG} --cflags $PKG)\"
-		echo libs=\"$(${HOSTPKG_CONFIG} --libs $PKG)\"
+		${HOSTPKG_CONFIG} --cflags ${PKG} > ${cflags}
+		${HOSTPKG_CONFIG} --libs ${PKG} > ${libs}
 		exit 0
 	fi
 
-	if ${HOSTPKG_CONFIG} --exists $PKG2; then
-		echo cflags=\"$(${HOSTPKG_CONFIG} --cflags $PKG2)\"
-		echo libs=\"$(${HOSTPKG_CONFIG} --libs $PKG2)\"
+	if ${HOSTPKG_CONFIG} --exists ${PKG2}; then
+		${HOSTPKG_CONFIG} --cflags ${PKG2} > ${cflags}
+		${HOSTPKG_CONFIG} --libs ${PKG2} > ${libs}
 		exit 0
 	fi
 fi
@@ -22,22 +25,22 @@ fi
 # (Even if it is installed, some distributions such as openSUSE cannot
 # find ncurses by pkg-config.)
 if [ -f /usr/include/ncursesw/ncurses.h ]; then
-	echo cflags=\"-D_GNU_SOURCE -I/usr/include/ncursesw\"
-	echo libs=\"-lncursesw\"
+	echo -D_GNU_SOURCE -I/usr/include/ncursesw > ${cflags}
+	echo -lncursesw > ${libs}
 	exit 0
 fi
 
 if [ -f /usr/include/ncurses/ncurses.h ]; then
-	echo cflags=\"-D_GNU_SOURCE -I/usr/include/ncurses\"
-	echo libs=\"-lncurses\"
+	echo -D_GNU_SOURCE -I/usr/include/ncurses > ${cflags}
+	echo -lncurses > ${libs}
 	exit 0
 fi
 
 # As a final fallback before giving up, check if $HOSTCC knows of a default
 # ncurses installation (e.g. from a vendor-specific sysroot).
 if echo '#include <ncurses.h>' | ${HOSTCC} -E - >/dev/null 2>&1; then
-	echo cflags=\"-D_GNU_SOURCE\"
-	echo libs=\"-lncurses\"
+	echo -D_GNU_SOURCE > ${cflags}
+	echo -lncurses > ${libs}
 	exit 0
 fi
 
diff --git a/scripts/kconfig/nconf-cfg.sh b/scripts/kconfig/nconf-cfg.sh
index 3a10bac2adb3..f871a2160e36 100755
--- a/scripts/kconfig/nconf-cfg.sh
+++ b/scripts/kconfig/nconf-cfg.sh
@@ -1,19 +1,22 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 
+cflags=$1
+libs=$2
+
 PKG="ncursesw menuw panelw"
 PKG2="ncurses menu panel"
 
 if [ -n "$(command -v ${HOSTPKG_CONFIG})" ]; then
 	if ${HOSTPKG_CONFIG} --exists $PKG; then
-		echo cflags=\"$(${HOSTPKG_CONFIG} --cflags $PKG)\"
-		echo libs=\"$(${HOSTPKG_CONFIG} --libs $PKG)\"
+		${HOSTPKG_CONFIG} --cflags ${PKG} > ${cflags}
+		${HOSTPKG_CONFIG} --libs ${PKG} > ${libs}
 		exit 0
 	fi
 
 	if ${HOSTPKG_CONFIG} --exists $PKG2; then
-		echo cflags=\"$(${HOSTPKG_CONFIG} --cflags $PKG2)\"
-		echo libs=\"$(${HOSTPKG_CONFIG} --libs $PKG2)\"
+		${HOSTPKG_CONFIG} --cflags ${PKG2} > ${cflags}
+		${HOSTPKG_CONFIG} --libs ${PKG2} > ${libs}
 		exit 0
 	fi
 fi
@@ -22,20 +25,20 @@ fi
 # (Even if it is installed, some distributions such as openSUSE cannot
 # find ncurses by pkg-config.)
 if [ -f /usr/include/ncursesw/ncurses.h ]; then
-	echo cflags=\"-D_GNU_SOURCE -I/usr/include/ncursesw\"
-	echo libs=\"-lncursesw -lmenuw -lpanelw\"
+	echo -D_GNU_SOURCE -I/usr/include/ncursesw > ${cflags}
+	echo -lncursesw -lmenuw -lpanelw > ${libs}
 	exit 0
 fi
 
 if [ -f /usr/include/ncurses/ncurses.h ]; then
-	echo cflags=\"-D_GNU_SOURCE -I/usr/include/ncurses\"
-	echo libs=\"-lncurses -lmenu -lpanel\"
+	echo -D_GNU_SOURCE -I/usr/include/ncurses > ${cflags}
+	echo -lncurses -lmenu -lpanel > ${libs}
 	exit 0
 fi
 
 if [ -f /usr/include/ncurses.h ]; then
-	echo cflags=\"-D_GNU_SOURCE\"
-	echo libs=\"-lncurses -lmenu -lpanel\"
+	echo -D_GNU_SOURCE > ${cflags}
+	echo -lncurses -lmenu -lpanel > ${libs}
 	exit 0
 fi
 
diff --git a/scripts/kconfig/qconf-cfg.sh b/scripts/kconfig/qconf-cfg.sh
index ad652cb53947..117f36e568fc 100755
--- a/scripts/kconfig/qconf-cfg.sh
+++ b/scripts/kconfig/qconf-cfg.sh
@@ -1,6 +1,10 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 
+cflags=$1
+libs=$2
+bin=$3
+
 PKG="Qt5Core Qt5Gui Qt5Widgets"
 
 if [ -z "$(command -v ${HOSTPKG_CONFIG})" ]; then
@@ -11,9 +15,9 @@ if [ -z "$(command -v ${HOSTPKG_CONFIG})" ]; then
 fi
 
 if ${HOSTPKG_CONFIG} --exists $PKG; then
-	echo cflags=\"-std=c++11 -fPIC $(${HOSTPKG_CONFIG} --cflags $PKG)\"
-	echo libs=\"$(${HOSTPKG_CONFIG} --libs $PKG)\"
-	echo moc=\"$(${HOSTPKG_CONFIG} --variable=host_bins Qt5Core)/moc\"
+	${HOSTPKG_CONFIG} --cflags ${PKG} > ${cflags}
+	${HOSTPKG_CONFIG} --libs ${PKG} > ${libs}
+	${HOSTPKG_CONFIG} --variable=host_bins Qt5Core > ${bin}
 	exit 0
 fi
 
diff --git a/scripts/remove-stale-files b/scripts/remove-stale-files
index ccadfa3afb2b..64b14aa5aebf 100755
--- a/scripts/remove-stale-files
+++ b/scripts/remove-stale-files
@@ -47,3 +47,5 @@ rm -f arch/riscv/purgatory/kexec-purgatory.c
 rm -f scripts/extract-cert
 
 rm -f arch/x86/purgatory/kexec-purgatory.c
+
+rm -f scripts/kconfig/[gmnq]conf-cfg
-- 
2.34.1