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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>
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‎Documentation/kbuild/makefiles.rst

+30-1
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@@ -749,6 +749,10 @@ Both possibilities are described in the following.
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hostprogs := lxdialog
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always-y := $(hostprogs)
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Kbuild provides the following shorthand for this:
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hostprogs-always-y := lxdialog
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This will tell kbuild to build lxdialog even if not referenced in
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any rule.
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@@ -831,7 +835,32 @@ The syntax is quite similar. The difference is to use "userprogs" instead of
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5.4 When userspace programs are actually built
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----------------------------------------------
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Same as "When host programs are actually built".
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Kbuild builds userspace programs only when told to do so.
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There are two ways to do this.
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(1) Add it as the prerequisite of another file
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Example::
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#net/bpfilter/Makefile
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userprogs := bpfilter_umh
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$(obj)/bpfilter_umh_blob.o: $(obj)/bpfilter_umh
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$(obj)/bpfilter_umh is built before $(obj)/bpfilter_umh_blob.o
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(2) Use always-y
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Example::
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userprogs := binderfs_example
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always-y := $(userprogs)
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Kbuild provides the following shorthand for this:
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userprogs-always-y := binderfs_example
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This will tell Kbuild to build binderfs_example when it visits this
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Makefile.
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6 Kbuild clean infrastructure
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=============================

‎samples/auxdisplay/Makefile

+1-2
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@@ -1,3 +1,2 @@
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# SPDX-License-Identifier: GPL-2.0
2-
userprogs := cfag12864b-example
3-
always-y := $(userprogs)
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userprogs-always-y += cfag12864b-example

‎samples/binderfs/Makefile

+1-2
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@@ -1,5 +1,4 @@
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# SPDX-License-Identifier: GPL-2.0-only
2-
userprogs := binderfs_example
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always-y := $(userprogs)
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userprogs-always-y += binderfs_example
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userccflags += -I usr/include

‎samples/connector/Makefile

+1-2
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@@ -1,7 +1,6 @@
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# SPDX-License-Identifier: GPL-2.0
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obj-$(CONFIG_SAMPLE_CONNECTOR) += cn_test.o
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4-
userprogs := ucon
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always-$(CONFIG_CC_CAN_LINK) := $(userprogs)
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userprogs-always-$(CONFIG_CC_CAN_LINK) += ucon
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userccflags += -I usr/include

‎samples/hidraw/Makefile

+1-2
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@@ -1,5 +1,4 @@
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# SPDX-License-Identifier: GPL-2.0
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userprogs := hid-example
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always-y := $(userprogs)
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userprogs-always-y += hid-example
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userccflags += -I usr/include

‎samples/mei/Makefile

+1-3
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@@ -1,7 +1,5 @@
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# SPDX-License-Identifier: GPL-2.0
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# Copyright (c) 2012-2019, Intel Corporation. All rights reserved.
3-
4-
userprogs := mei-amt-version
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always-y := $(userprogs)
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userprogs-always-y += mei-amt-version
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userccflags += -I usr/include

‎samples/pidfd/Makefile

+1-3
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@@ -1,6 +1,4 @@
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# SPDX-License-Identifier: GPL-2.0
2-
3-
usertprogs := pidfd-metadata
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always-y := $(userprogs)
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usertprogs-always-y += pidfd-metadata
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userccflags += -I usr/include

‎samples/seccomp/Makefile

+1-3
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@@ -1,8 +1,6 @@
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# SPDX-License-Identifier: GPL-2.0
2-
userprogs := bpf-fancy dropper bpf-direct user-trap
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userprogs-always-y += bpf-fancy dropper bpf-direct user-trap
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bpf-fancy-objs := bpf-fancy.o bpf-helper.o
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userccflags += -I usr/include
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always-y := $(userprogs)

‎samples/timers/Makefile

+1-2
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@@ -1,5 +1,4 @@
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# SPDX-License-Identifier: GPL-2.0
2-
userprogs := hpet_example
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always-y := $(userprogs)
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userprogs-always-y += hpet_example
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userccflags += -I usr/include

‎samples/uhid/Makefile

+1-2
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,4 @@
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# SPDX-License-Identifier: GPL-2.0-only
2-
userprogs := uhid-example
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always-y := $(userprogs)
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userprogs-always-y += uhid-example
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userccflags += -I usr/include

‎samples/vfs/Makefile

+1-2
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@@ -1,5 +1,4 @@
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# SPDX-License-Identifier: GPL-2.0-only
2-
userprogs := test-fsmount test-statx
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always-y := $(userprogs)
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userprogs-always-y += test-fsmount test-statx
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userccflags += -I usr/include

‎samples/watch_queue/Makefile

+1-2
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@@ -1,5 +1,4 @@
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# SPDX-License-Identifier: GPL-2.0-only
2-
userprogs := watch_test
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always-y := $(userprogs)
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userprogs-always-y += watch_test
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userccflags += -I usr/include

‎samples/watchdog/Makefile

+1-2
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@@ -1,3 +1,2 @@
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# SPDX-License-Identifier: GPL-2.0
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userprogs := watchdog-simple
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always-y := $(userprogs)
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userprogs-always-y += watchdog-simple

‎scripts/Makefile

+8-10
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@@ -3,14 +3,14 @@
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# scripts contains sources for various helper programs used throughout
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# the kernel for the build process.
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6-
always-$(CONFIG_BUILD_BIN2C) += bin2c
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always-$(CONFIG_KALLSYMS) += kallsyms
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always-$(BUILD_C_RECORDMCOUNT) += recordmcount
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always-$(CONFIG_BUILDTIME_TABLE_SORT) += sorttable
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always-$(CONFIG_ASN1) += asn1_compiler
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always-$(CONFIG_MODULE_SIG_FORMAT) += sign-file
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always-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += extract-cert
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always-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE) += insert-sys-cert
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hostprogs-always-$(CONFIG_BUILD_BIN2C) += bin2c
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hostprogs-always-$(CONFIG_KALLSYMS) += kallsyms
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hostprogs-always-$(BUILD_C_RECORDMCOUNT) += recordmcount
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hostprogs-always-$(CONFIG_BUILDTIME_TABLE_SORT) += sorttable
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hostprogs-always-$(CONFIG_ASN1) += asn1_compiler
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hostprogs-always-$(CONFIG_MODULE_SIG_FORMAT) += sign-file
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hostprogs-always-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += extract-cert
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hostprogs-always-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE) += insert-sys-cert
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HOSTCFLAGS_sorttable.o = -I$(srctree)/tools/include
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HOSTCFLAGS_asn1_compiler.o = -I$(srctree)/include
@@ -26,8 +26,6 @@ HOSTCFLAGS_sorttable.o += -DUNWINDER_ORC_ENABLED
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HOSTLDLIBS_sorttable = -lpthread
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endif
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hostprogs := $(always-y) $(always-m)
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# The following programs are only built on demand
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hostprogs += unifdef
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‎scripts/Makefile.clean

+9-3
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@@ -27,9 +27,15 @@ subdir-ymn := $(addprefix $(obj)/,$(subdir-ymn))
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# build a list of files to remove, usually relative to the current
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# directory
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30-
__clean-files := $(extra-y) $(extra-m) $(extra-) \
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$(always) $(always-y) $(always-m) $(always-) $(targets) $(clean-files) \
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$(hostprogs) $(hostprogs-y) $(hostprogs-m) $(hostprogs-) $(userprogs)
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__clean-files := \
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$(clean-files) $(targets) $(hostprogs) $(userprogs) \
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$(extra-y) $(extra-m) $(extra-) \
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$(always-y) $(always-m) $(always-) \
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$(hostprogs-always-y) $(hostprogs-always-m) $(hostprogs-always-) \
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$(userprogs-always-y) $(userprogs-always-m) $(userprogs-always-)
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# deprecated
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__clean-files += $(always) $(hostprogs-y) $(hostprogs-m) $(hostprogs-)
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__clean-files := $(filter-out $(no-clean-files), $(__clean-files))
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‎scripts/Makefile.lib

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@@ -68,6 +68,17 @@ real-obj-m := $(foreach m, $(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))
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always-y += $(always-m)
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# hostprogs-always-y += foo
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# ... is a shorthand for
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# hostprogs += foo
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# always-y += foo
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hostprogs += $(hostprogs-always-y) $(hostprogs-always-m)
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always-y += $(hostprogs-always-y) $(hostprogs-always-m)
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# userprogs-always-y is likewise.
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userprogs += $(userprogs-always-y) $(userprogs-always-m)
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always-y += $(userprogs-always-y) $(userprogs-always-m)
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# DTB
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# If CONFIG_OF_ALL_DTBS is enabled, all DT blobs are built
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extra-y += $(dtb-y)

‎scripts/basic/Makefile

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@@ -2,5 +2,4 @@
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#
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# fixdep: used to generate dependency information during build process
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5-
hostprogs := fixdep
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always-y := $(hostprogs)
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hostprogs-always-y += fixdep

‎scripts/dtc/Makefile

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@@ -1,9 +1,8 @@
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# SPDX-License-Identifier: GPL-2.0
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# scripts/dtc makefile
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4-
hostprogs := dtc
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always-$(CONFIG_DTC) += $(hostprogs)
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always-$(CHECK_DT_BINDING) += $(hostprogs)
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hostprogs-always-$(CONFIG_DTC) += dtc
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hostprogs-always-$(CHECK_DT_BINDING) += dtc
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dtc-objs := dtc.o flattree.o fstree.o data.o livetree.o treesource.o \
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srcpos.o checks.o util.o

‎scripts/genksyms/Makefile

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@@ -1,7 +1,6 @@
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# SPDX-License-Identifier: GPL-2.0
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3-
hostprogs := genksyms
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always-y := $(hostprogs)
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hostprogs-always-y += genksyms
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genksyms-objs := genksyms.o parse.tab.o lex.lex.o
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‎scripts/mod/Makefile

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@@ -1,8 +1,8 @@
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# SPDX-License-Identifier: GPL-2.0
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OBJECT_FILES_NON_STANDARD := y
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4-
hostprogs := modpost mk_elfconfig
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always-y := $(hostprogs) empty.o
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hostprogs-always-y += modpost mk_elfconfig
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always-y += empty.o
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modpost-objs := modpost.o file2alias.o sumversion.o
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‎scripts/selinux/genheaders/Makefile

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@@ -1,7 +1,5 @@
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# SPDX-License-Identifier: GPL-2.0
2-
hostprogs := genheaders
2+
hostprogs-always-y += genheaders
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HOST_EXTRACFLAGS += \
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-I$(srctree)/include/uapi -I$(srctree)/include \
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-I$(srctree)/security/selinux/include
6-
7-
always-y := $(hostprogs)

‎scripts/selinux/mdp/Makefile

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@@ -1,8 +1,7 @@
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# SPDX-License-Identifier: GPL-2.0
2-
hostprogs := mdp
2+
hostprogs-always-y += mdp
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HOST_EXTRACFLAGS += \
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-I$(srctree)/include/uapi -I$(srctree)/include \
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-I$(srctree)/security/selinux/include -I$(objtree)/include
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7-
always-y := $(hostprogs)
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clean-files := policy.* file_contexts

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