kbuild: introduce hostprogs-always-y and userprogs-always-y

To build host programs, you need to add the program names to 'hostprogs' to use the necessary build rule, but it is not enough to build them because there is no dependency. There are two types of host programs: built as the prerequisite of another (e.g. gen_crc32table in lib/Makefile), or always built when Kbuild visits the Makefile (e.g. genksyms in scripts/genksyms/Makefile). The latter is typical in Makefiles under scripts/, which contains host programs globally used during the kernel build. To build them, you need to add them to both 'hostprogs' and 'always-y'. This commit adds hostprogs-always-y as a shorthand. The same applies to user programs. net/bpfilter/Makefile builds bpfilter_umh on demand, hence always-y is unneeded. In contrast, programs under samples/ are added to both 'userprogs' and 'always-y' so they are always built when Kbuild visits the Makefiles. userprogs-always-y works as a shorthand. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2020-08-01 21:27:18 +09:00 · 2020-08-01 21:27:18 +09:00 · faabed295c
parent 85569d19d0
commit faabed295c
22 changed files with 78 additions and 55 deletions
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@ -749,6 +749,10 @@ Both possibilities are described in the following.
 		hostprogs     := lxdialog
 		always-y      := $(hostprogs)

+	Kbuild provides the following shorthand for this:
+
+		hostprogs-always-y := lxdialog
+
 	This will tell kbuild to build lxdialog even if not referenced in
 	any rule.

@ -831,7 +835,32 @@ The syntax is quite similar. The difference is to use "userprogs" instead of
 5.4 When userspace programs are actually built
 ----------------------------------------------

-	Same as "When host programs are actually built".
+	Kbuild builds userspace programs only when told to do so.
+	There are two ways to do this.
+
+	(1) Add it as the prerequisite of another file
+
+	Example::
+
+		#net/bpfilter/Makefile
+		userprogs := bpfilter_umh
+		$(obj)/bpfilter_umh_blob.o: $(obj)/bpfilter_umh
+
+	$(obj)/bpfilter_umh is built before $(obj)/bpfilter_umh_blob.o
+
+	(2) Use always-y
+
+	Example::
+
+		userprogs := binderfs_example
+		always-y := $(userprogs)
+
+	Kbuild provides the following shorthand for this:
+
+		userprogs-always-y := binderfs_example
+
+	This will tell Kbuild to build binderfs_example when it visits this
+	Makefile.

 6 Kbuild clean infrastructure
 =============================
--- a/samples/auxdisplay/Makefile
+++ b/samples/auxdisplay/Makefile
@ -1,3 +1,2 @@
 # SPDX-License-Identifier: GPL-2.0
-userprogs := cfag12864b-example
-always-y := $(userprogs)
+userprogs-always-y += cfag12864b-example
--- a/samples/binderfs/Makefile
+++ b/samples/binderfs/Makefile
@ -1,5 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-userprogs := binderfs_example
-always-y := $(userprogs)
+userprogs-always-y += binderfs_example

 userccflags += -I usr/include
--- a/samples/connector/Makefile
+++ b/samples/connector/Makefile
@ -1,7 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_SAMPLE_CONNECTOR) += cn_test.o

-userprogs := ucon
-always-$(CONFIG_CC_CAN_LINK) := $(userprogs)
+userprogs-always-$(CONFIG_CC_CAN_LINK) += ucon

 userccflags += -I usr/include
--- a/samples/hidraw/Makefile
+++ b/samples/hidraw/Makefile
@ -1,5 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
-userprogs := hid-example
-always-y := $(userprogs)
+userprogs-always-y += hid-example

 userccflags += -I usr/include
--- a/samples/mei/Makefile
+++ b/samples/mei/Makefile
@ -1,7 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 # Copyright (c) 2012-2019, Intel Corporation. All rights reserved.
-
-userprogs := mei-amt-version
-always-y := $(userprogs)
+userprogs-always-y += mei-amt-version

 userccflags += -I usr/include
--- a/samples/pidfd/Makefile
+++ b/samples/pidfd/Makefile
@ -1,6 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
-
-usertprogs := pidfd-metadata
-always-y := $(userprogs)
+usertprogs-always-y += pidfd-metadata

 userccflags += -I usr/include
--- a/samples/seccomp/Makefile
+++ b/samples/seccomp/Makefile
@ -1,8 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
-userprogs := bpf-fancy dropper bpf-direct user-trap
+userprogs-always-y += bpf-fancy dropper bpf-direct user-trap

 bpf-fancy-objs := bpf-fancy.o bpf-helper.o

 userccflags += -I usr/include
-
-always-y := $(userprogs)
--- a/samples/timers/Makefile
+++ b/samples/timers/Makefile
@ -1,5 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
-userprogs := hpet_example
-always-y := $(userprogs)
+userprogs-always-y += hpet_example

 userccflags += -I usr/include
--- a/samples/uhid/Makefile
+++ b/samples/uhid/Makefile
@ -1,5 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-userprogs := uhid-example
-always-y := $(userprogs)
+userprogs-always-y += uhid-example

 userccflags += -I usr/include
--- a/samples/vfs/Makefile
+++ b/samples/vfs/Makefile
@ -1,5 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-userprogs := test-fsmount test-statx
-always-y := $(userprogs)
+userprogs-always-y += test-fsmount test-statx

 userccflags += -I usr/include
--- a/samples/watch_queue/Makefile
+++ b/samples/watch_queue/Makefile
@ -1,5 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-userprogs := watch_test
-always-y := $(userprogs)
+userprogs-always-y += watch_test

 userccflags += -I usr/include
--- a/samples/watchdog/Makefile
+++ b/samples/watchdog/Makefile
@ -1,3 +1,2 @@
 # SPDX-License-Identifier: GPL-2.0
-userprogs := watchdog-simple
-always-y := $(userprogs)
+userprogs-always-y += watchdog-simple
--- a/scripts/Makefile
+++ b/scripts/Makefile
@ -3,14 +3,14 @@
 # scripts contains sources for various helper programs used throughout
 # the kernel for the build process.

-always-$(CONFIG_BUILD_BIN2C)			+= bin2c
-always-$(CONFIG_KALLSYMS)			+= kallsyms
-always-$(BUILD_C_RECORDMCOUNT)			+= recordmcount
-always-$(CONFIG_BUILDTIME_TABLE_SORT)		+= sorttable
-always-$(CONFIG_ASN1)				+= asn1_compiler
-always-$(CONFIG_MODULE_SIG_FORMAT)		+= sign-file
-always-$(CONFIG_SYSTEM_TRUSTED_KEYRING)		+= extract-cert
-always-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE)	+= insert-sys-cert
+hostprogs-always-$(CONFIG_BUILD_BIN2C)			+= bin2c
+hostprogs-always-$(CONFIG_KALLSYMS)			+= kallsyms
+hostprogs-always-$(BUILD_C_RECORDMCOUNT)		+= recordmcount
+hostprogs-always-$(CONFIG_BUILDTIME_TABLE_SORT)		+= sorttable
+hostprogs-always-$(CONFIG_ASN1)				+= asn1_compiler
+hostprogs-always-$(CONFIG_MODULE_SIG_FORMAT)		+= sign-file
+hostprogs-always-$(CONFIG_SYSTEM_TRUSTED_KEYRING)	+= extract-cert
+hostprogs-always-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE)	+= insert-sys-cert

 HOSTCFLAGS_sorttable.o = -I$(srctree)/tools/include
 HOSTCFLAGS_asn1_compiler.o = -I$(srctree)/include
@ -26,8 +26,6 @@ HOSTCFLAGS_sorttable.o += -DUNWINDER_ORC_ENABLED
 HOSTLDLIBS_sorttable = -lpthread
 endif

-hostprogs := $(always-y) $(always-m)
-
 # The following programs are only built on demand
 hostprogs += unifdef

--- a/scripts/Makefile.clean
+++ b/scripts/Makefile.clean
@ -27,9 +27,15 @@ subdir-ymn	:= $(addprefix $(obj)/,$(subdir-ymn))
 # build a list of files to remove, usually relative to the current
 # directory

-__clean-files	:= $(extra-y) $(extra-m) $(extra-)       \
-		   $(always) $(always-y) $(always-m) $(always-) $(targets) $(clean-files)   \
-		   $(hostprogs) $(hostprogs-y) $(hostprogs-m) $(hostprogs-) $(userprogs)
+__clean-files	:= \
+	$(clean-files) $(targets) $(hostprogs) $(userprogs) \
+	$(extra-y) $(extra-m) $(extra-) \
+	$(always-y) $(always-m) $(always-) \
+	$(hostprogs-always-y) $(hostprogs-always-m) $(hostprogs-always-) \
+	$(userprogs-always-y) $(userprogs-always-m) $(userprogs-always-)
+
+# deprecated
+__clean-files	+= $(always) $(hostprogs-y) $(hostprogs-m) $(hostprogs-)

 __clean-files   := $(filter-out $(no-clean-files), $(__clean-files))

--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@ -68,6 +68,17 @@ real-obj-m := $(foreach m, $(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))

 always-y += $(always-m)

+# hostprogs-always-y += foo
+# ... is a shorthand for
+# hostprogs += foo
+# always-y  += foo
+hostprogs += $(hostprogs-always-y) $(hostprogs-always-m)
+always-y += $(hostprogs-always-y) $(hostprogs-always-m)
+
+# userprogs-always-y is likewise.
+userprogs += $(userprogs-always-y) $(userprogs-always-m)
+always-y += $(userprogs-always-y) $(userprogs-always-m)
+
 # DTB
 # If CONFIG_OF_ALL_DTBS is enabled, all DT blobs are built
 extra-y				+= $(dtb-y)
--- a/scripts/basic/Makefile
+++ b/scripts/basic/Makefile
@ -2,5 +2,4 @@
 #
 # fixdep: used to generate dependency information during build process

-hostprogs	:= fixdep
-always-y	:= $(hostprogs)
+hostprogs-always-y	+= fixdep
--- a/scripts/dtc/Makefile
+++ b/scripts/dtc/Makefile
@ -1,9 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 # scripts/dtc makefile

-hostprogs			:= dtc
-always-$(CONFIG_DTC)		+= $(hostprogs)
-always-$(CHECK_DT_BINDING)	+= $(hostprogs)
+hostprogs-always-$(CONFIG_DTC)		+= dtc
+hostprogs-always-$(CHECK_DT_BINDING)	+= dtc

 dtc-objs	:= dtc.o flattree.o fstree.o data.o livetree.o treesource.o \
 		   srcpos.o checks.o util.o
--- a/scripts/genksyms/Makefile
+++ b/scripts/genksyms/Makefile
@ -1,7 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0

-hostprogs	:= genksyms
-always-y	:= $(hostprogs)
+hostprogs-always-y	+= genksyms

 genksyms-objs	:= genksyms.o parse.tab.o lex.lex.o

--- a/scripts/mod/Makefile
+++ b/scripts/mod/Makefile
@ -1,8 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 OBJECT_FILES_NON_STANDARD := y

-hostprogs	:= modpost mk_elfconfig
-always-y	:= $(hostprogs) empty.o
+hostprogs-always-y	+= modpost mk_elfconfig
+always-y		+= empty.o

 modpost-objs	:= modpost.o file2alias.o sumversion.o

--- a/scripts/selinux/genheaders/Makefile
+++ b/scripts/selinux/genheaders/Makefile
@ -1,7 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
-hostprogs	:= genheaders
+hostprogs-always-y += genheaders
 HOST_EXTRACFLAGS += \
 	-I$(srctree)/include/uapi -I$(srctree)/include \
 	-I$(srctree)/security/selinux/include
-
-always-y	:= $(hostprogs)
--- a/scripts/selinux/mdp/Makefile
+++ b/scripts/selinux/mdp/Makefile
@ -1,8 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
-hostprogs	:= mdp
+hostprogs-always-y += mdp
 HOST_EXTRACFLAGS += \
 	-I$(srctree)/include/uapi -I$(srctree)/include \
 	-I$(srctree)/security/selinux/include -I$(objtree)/include

-always-y	:= $(hostprogs)
 clean-files	:= policy.* file_contexts