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>

9 files changed, 36 insertions, 27 deletions

diff --git a/scripts/Makefile b/scripts/Makefile
index 95ecf970c74c..bc018e4b733e 100644
--- 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
 
diff --git a/scripts/Makefile.clean b/scripts/Makefile.clean
index 3cdf31218198..d9e0ceace6a6 100644
--- 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))
 
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 5cfd377778b4..841ac038132b 100644
--- 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)
diff --git a/scripts/basic/Makefile b/scripts/basic/Makefile
index 290dd27d2809..eeb6a38c5551 100644
--- 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
diff --git a/scripts/dtc/Makefile b/scripts/dtc/Makefile
index 0b44917f981c..a698ece43fff 100644
--- 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
diff --git a/scripts/genksyms/Makefile b/scripts/genksyms/Makefile
index d328de1e10ee..ce4f99935de5 100644
--- 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
 
diff --git a/scripts/mod/Makefile b/scripts/mod/Makefile
index 296b6a3878b2..78071681d924 100644
--- 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
 
diff --git a/scripts/selinux/genheaders/Makefile b/scripts/selinux/genheaders/Makefile
index 70cf8d95d07c..1faf7f07e8db 100644
--- 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	:= $(hostprogs)
diff --git a/scripts/selinux/mdp/Makefile b/scripts/selinux/mdp/Makefile
index 3026f3c2aa2b..d61058ddd15c 100644
--- a/scripts/selinux/mdp/Makefile
+++ b/scripts/selinux/mdp/Makefile
@@ -1,8 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
-hostprogs	:= mdp
+hostprogs-always-y += mdp
 HOST_EXTRACFLAGS += \
 	-I$(srctree)/include/uapi -I$(srctree)/include \
 	-I$(srctree)/security/selinux/include -I$(objtree)/include
 
-always-y	:= $(hostprogs)
 clean-files	:= policy.* file_contexts