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>

diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index 14d8e7d..b81b891 100644 (file)
--- 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
 =============================

diff --git a/samples/auxdisplay/Makefile b/samples/auxdisplay/Makefile
index dbdf939..19d5568 100644 (file)
--- 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

diff --git a/samples/binderfs/Makefile b/samples/binderfs/Makefile
index 989e4ba..629e43b 100644 (file)
--- 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

diff --git a/samples/connector/Makefile b/samples/connector/Makefile
index 50cb40e..d98a9e0 100644 (file)
--- 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

diff --git a/samples/hidraw/Makefile b/samples/hidraw/Makefile
index d2c77ed..594d989 100644 (file)
--- 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

diff --git a/samples/mei/Makefile b/samples/mei/Makefile
index 329411f..c54b8a0 100644 (file)
--- 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

diff --git a/samples/pidfd/Makefile b/samples/pidfd/Makefile
index 6e5b67e..9754e2d 100644 (file)
--- 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

diff --git a/samples/seccomp/Makefile b/samples/seccomp/Makefile
index 75916c2..c85ae0e 100644 (file)
--- 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)

diff --git a/samples/timers/Makefile b/samples/timers/Makefile
index 15c7ddb..e6836cd 100644 (file)
--- 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

diff --git a/samples/uhid/Makefile b/samples/uhid/Makefile
index 9e652fc..0aa424e 100644 (file)
--- 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

diff --git a/samples/vfs/Makefile b/samples/vfs/Makefile
index 00b6824..6377a67 100644 (file)
--- 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

diff --git a/samples/watch_queue/Makefile b/samples/watch_queue/Makefile
index 792b22f..c0db3a6 100644 (file)
--- 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

diff --git a/samples/watchdog/Makefile b/samples/watchdog/Makefile
index 17384cf..ab39d23 100644 (file)
--- 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

diff --git a/scripts/Makefile b/scripts/Makefile
index 95ecf97..bc018e4 100644 (file)
--- 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 3cdf312..d9e0cea 100644 (file)
--- 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 5cfd377..841ac03 100644 (file)
--- 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 290dd27..eeb6a38 100644 (file)
--- 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 0b44917..a698ece 100644 (file)
--- 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 d328de1..ce4f999 100644 (file)
--- 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 296b6a3..7807168 100644 (file)
--- 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 70cf8d9..1faf7f0 100644 (file)
--- 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 3026f3c..d61058d 100644 (file)
--- 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