Makefile

# SPDX-License-Identifier: GPL-2.0
#
# kbuild file for usr/ - including initramfs image
#

suffix_y = $(subst $\",,$(CONFIG_INITRAMFS_COMPRESSION))
datafile_y = initramfs_data.cpio$(suffix_y)
datafile_d_y = .$(datafile_y).d
AFLAGS_initramfs_data.o += -DINITRAMFS_IMAGE="usr/$(datafile_y)"

# clean rules do not have CONFIG_INITRAMFS_COMPRESSION.  So clean up after all
# possible compression formats.
clean-files += initramfs_data.cpio*

# Generate builtin.o based on initramfs_data.o
obj-$(CONFIG_BLK_DEV_INITRD) := initramfs_data.o

# initramfs_data.o contains the compressed initramfs_data.cpio image.
# The image is included using .incbin, a dependency which is not
# tracked automatically.
$(obj)/initramfs_data.o: $(obj)/$(datafile_y) FORCE

#####
# Generate the initramfs cpio archive

hostprogs-y := gen_init_cpio
ramfs-input := $(if $(filter-out "",$(CONFIG_INITRAMFS_SOURCE)), \
			$(shell echo $(CONFIG_INITRAMFS_SOURCE)),-d)
ramfs-args  := \
        $(if $(CONFIG_INITRAMFS_ROOT_UID), -u $(CONFIG_INITRAMFS_ROOT_UID)) \
        $(if $(CONFIG_INITRAMFS_ROOT_GID), -g $(CONFIG_INITRAMFS_ROOT_GID))

# $(datafile_d_y) is used to identify all files included
# in initramfs and to detect if any files are added/removed.
# Removed files are identified by directory timestamp being updated
# The dependency list is generated by gen_initramfs.sh -l
ifneq ($(wildcard $(obj)/$(datafile_d_y)),)
	include $(obj)/$(datafile_d_y)
endif

quiet_cmd_initfs = GEN     $@
      cmd_initfs = $(CONFIG_SHELL) $< -o $@ -l $(obj)/$(datafile_d_y) $(ramfs-args) $(ramfs-input)

targets := $(datafile_y)

# do not try to update files included in initramfs
$(deps_initramfs): ;

# We rebuild initramfs_data.cpio if:
# 1) Any included file is newer than initramfs_data.cpio
# 2) There are changes in which files are included (added or deleted)
# 3) If gen_init_cpio are newer than initramfs_data.cpio
# 4) Arguments to gen_initramfs.sh changes
$(obj)/$(datafile_y): $(src)/gen_initramfs.sh $(obj)/gen_init_cpio $(deps_initramfs) FORCE
	$(call if_changed,initfs)

subdir-$(CONFIG_UAPI_HEADER_TEST) += include