linux/usr/Makefile
Sam Ravnborg 58a2f7d85a kbuild: do not try to build content of initramfs
When a file supplied via CONFIG_INITRAMFS pointed to a file
for which kbuild had a rule to compile it (foo.c => foo.o)
then kbuild would compile the file before adding the
file to the initramfs.

Teach make that files included in initramfs shall not be updated by adding
an 'empty command'. (See "Using Empty Commands" in info make).

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2006-08-07 20:58:28 +02:00

51 lines
1.8 KiB
Makefile

#
# kbuild file for usr/ - including initramfs image
#
klibcdirs:;
# 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
#####
# 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)