+#
+# kbuild file for usr/ - including initramfs image
+#
-obj-y := initramfs_data.o
-
-host-progs := gen_init_cpio
+klibcdirs:;
-clean-files := initramfs_data.cpio.gz
+# Generate builtin.o based on initramfs_data.o
+obj-y := initramfs_data.o
# initramfs_data.o contains the initramfs_data.cpio.gz image.
# The image is included using .incbin, a dependency which is not
# tracked automatically.
$(obj)/initramfs_data.o: $(obj)/initramfs_data.cpio.gz FORCE
-# initramfs-y are the programs which will be copied into the CPIO
-# archive. Currently, the filenames are hardcoded in gen_init_cpio,
-# but we need the information for the build as well, so it's duplicated
-# here.
-
-# Commented out for now
-# initramfs-y := $(obj)/root/hello
-
-quiet_cmd_cpio = CPIO $@
- cmd_cpio = ./$< > $@
-
-$(obj)/initramfs_data.cpio: $(obj)/gen_init_cpio $(initramfs-y) FORCE
- $(call if_changed,cpio)
-
-targets += initramfs_data.cpio
-
-$(obj)/initramfs_data.cpio.gz: $(obj)/initramfs_data.cpio FORCE
- $(call if_changed,gzip)
-
-targets += initramfs_data.cpio.gz
+#####
+# Generate the initramfs cpio archive
+
+hostprogs-y := gen_init_cpio
+initramfs := $(CONFIG_SHELL) $(srctree)/scripts/gen_initramfs_list.sh
+ramfs-input := $(if $(filter-out "",$(CONFIG_INITRAMFS_SOURCE)), \
+ $(CONFIG_INITRAMFS_SOURCE),-d)
+ramfs-args := \
+ $(if $(CONFIG_INITRAMFS_ROOT_UID), -u $(CONFIG_INITRAMFS_ROOT_UID)) \
+ $(if $(CONFIG_INITRAMFS_ROOT_GID), -g $(CONFIG_INITRAMFS_ROOT_GID))
+
+# .initramfs_data.cpio.gz.d is used to identify all files included
+# in initramfs and to detect if any files are added/removed.
+# Removed files are identified by directory timestamp being updated
+# The dependency list is generated by gen_initramfs.sh -l
+ifneq ($(wildcard $(obj)/.initramfs_data.cpio.gz.d),)
+ include $(obj)/.initramfs_data.cpio.gz.d
+endif
+
+quiet_cmd_initfs = GEN $@
+ cmd_initfs = $(initramfs) -o $@ $(ramfs-args) $(ramfs-input)
+
+targets := initramfs_data.cpio.gz
+# do not try to update files included in initramfs
+$(deps_initramfs): ;
+
+$(deps_initramfs): klibcdirs
+# We rebuild initramfs_data.cpio.gz if:
+# 1) Any included file is newer then initramfs_data.cpio.gz
+# 2) There are changes in which files are included (added or deleted)
+# 3) If gen_init_cpio are newer than initramfs_data.cpio.gz
+# 4) arguments to gen_initramfs.sh changes
+$(obj)/initramfs_data.cpio.gz: $(obj)/gen_init_cpio $(deps_initramfs) klibcdirs
+ $(Q)$(initramfs) -l $(ramfs-input) > $(obj)/.initramfs_data.cpio.gz.d
+ $(call if_changed,initfs)