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P J P 9ba4bcb645 initramfs: read CONFIG_RD_ variables for initramfs compression

When expert configuration option(CONFIG_EXPERT) is enabled, menuconfig
offers a choice of compression algorithm to compress initial ramfs image;
This choice is stored into CONFIG_RD_* variables.  But usr/Makefile uses
earlier INITRAMFS_COMPRESSION_* macros to build initial ramfs file.  Since
none of them is defined, resulting 'initramfs_data.cpio' file remains
un-compressed.

This patch updates the Makefile to use CONFIG_RD_* variables and adds
support for LZ4 compression algorithm.  Also updates the
'gen_initramfs_list.sh' script to check whether a selected compression
command is accessible or not.  And fall-back to default gzip(1)
compression when it is not.

Signed-off-by: P J P <prasad@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2013-11-13 12:09:26 +09:00

2.3 KiB

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kbuild file for usr/ - including initramfs image

klibcdirs:; PHONY += klibcdirs

Bzip2

suffix_$(CONFIG_RD_BZIP2) = .bz2

Lzma

suffix_$(CONFIG_RD_LZMA) = .lzma

XZ

suffix_$(CONFIG_RD_XZ) = .xz

Lzo

suffix_$(CONFIG_RD_LZO) = .lzo

Lz4

suffix_$(CONFIG_RD_LZ4) = .lz4

Gzip

suffix_$(CONFIG_RD_GZIP) = .gz

AFLAGS_initramfs_data.o += -DINITRAMFS_IMAGE="usr/initramfs_data.cpio$(suffix_y)"

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: $(obj)/initramfs_data.cpio$(suffix_y) 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)),
$(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))

.initramfs_data.cpio.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.d),) include $(obj)/.initramfs_data.cpio.d endif

quiet_cmd_initfs = GEN $@ cmd_initfs = $(initramfs) -o $@ $(ramfs-args) $(ramfs-input)

targets := initramfs_data.cpio.gz initramfs_data.cpio.bz2
initramfs_data.cpio.lzma initramfs_data.cpio.xz
initramfs_data.cpio.lzo initramfs_data.cpio.lz4
initramfs_data.cpio

do not try to update files included in initramfs

$(deps_initramfs): ;

$(deps_initramfs): klibcdirs

We rebuild initramfs_data.cpio if:

1) Any included file is newer then 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

$(obj)/initramfs_data.cpio$(suffix_y): $(obj)/gen_init_cpio $(deps_initramfs) klibcdirs $(Q)$(initramfs) -l $(ramfs-input) > $(obj)/.initramfs_data.cpio.d $(call if_changed,initfs)

2.3 KiB Raw Blame History