forked from Minki/linux
65e00e04e5
Currently, usr/gen_initramfs.sh takes care of all the use-cases:
[1] generates a cpio file unless CONFIG_INITRAMFS_SOURCE points to
a single cpio archive
[2] If CONFIG_INITRAMFS_SOURCE is the path to a cpio archive,
use it as-is.
[3] Compress the cpio file according to CONFIG_INITRAMFS_COMPRESSION_*
unless it is passed a compressed archive.
To simplify the script, move [2] and [3] to usr/Makefile.
If CONFIG_INITRAMFS_SOURCE is the path to a cpio archive, there is
no need to run this shell script.
For the cpio archive compression, you can re-use the rules from
scripts/Makefile.lib .
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
210 lines
7.1 KiB
Plaintext
210 lines
7.1 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0
|
|
#
|
|
# Configuration for initramfs
|
|
#
|
|
|
|
config INITRAMFS_SOURCE
|
|
string "Initramfs source file(s)"
|
|
default ""
|
|
help
|
|
This can be either a single cpio archive with a .cpio suffix or a
|
|
space-separated list of directories and files for building the
|
|
initramfs image. A cpio archive should contain a filesystem archive
|
|
to be used as an initramfs image. Directories should contain a
|
|
filesystem layout to be included in the initramfs image. Files
|
|
should contain entries according to the format described by the
|
|
"usr/gen_init_cpio" program in the kernel tree.
|
|
|
|
When multiple directories and files are specified then the
|
|
initramfs image will be the aggregate of all of them.
|
|
|
|
See <file:Documentation/driver-api/early-userspace/early_userspace_support.rst> for more details.
|
|
|
|
If you are not sure, leave it blank.
|
|
|
|
config INITRAMFS_FORCE
|
|
bool "Ignore the initramfs passed by the bootloader"
|
|
depends on CMDLINE_EXTEND || CMDLINE_FORCE
|
|
help
|
|
This option causes the kernel to ignore the initramfs image
|
|
(or initrd image) passed to it by the bootloader. This is
|
|
analogous to CMDLINE_FORCE, which is found on some architectures,
|
|
and is useful if you cannot or don't want to change the image
|
|
your bootloader passes to the kernel.
|
|
|
|
config INITRAMFS_ROOT_UID
|
|
int "User ID to map to 0 (user root)"
|
|
depends on INITRAMFS_SOURCE!=""
|
|
default "0"
|
|
help
|
|
If INITRAMFS_SOURCE points to a directory, files owned by this UID
|
|
(-1 = current user) will be owned by root in the resulting image.
|
|
|
|
If you are not sure, leave it set to "0".
|
|
|
|
config INITRAMFS_ROOT_GID
|
|
int "Group ID to map to 0 (group root)"
|
|
depends on INITRAMFS_SOURCE!=""
|
|
default "0"
|
|
help
|
|
If INITRAMFS_SOURCE points to a directory, files owned by this GID
|
|
(-1 = current group) will be owned by root in the resulting image.
|
|
|
|
If you are not sure, leave it set to "0".
|
|
|
|
config RD_GZIP
|
|
bool "Support initial ramdisk/ramfs compressed using gzip"
|
|
default y
|
|
select DECOMPRESS_GZIP
|
|
help
|
|
Support loading of a gzip encoded initial ramdisk or cpio buffer.
|
|
If unsure, say Y.
|
|
|
|
config RD_BZIP2
|
|
bool "Support initial ramdisk/ramfs compressed using bzip2"
|
|
default y
|
|
select DECOMPRESS_BZIP2
|
|
help
|
|
Support loading of a bzip2 encoded initial ramdisk or cpio buffer
|
|
If unsure, say N.
|
|
|
|
config RD_LZMA
|
|
bool "Support initial ramdisk/ramfs compressed using LZMA"
|
|
default y
|
|
select DECOMPRESS_LZMA
|
|
help
|
|
Support loading of a LZMA encoded initial ramdisk or cpio buffer
|
|
If unsure, say N.
|
|
|
|
config RD_XZ
|
|
bool "Support initial ramdisk/ramfs compressed using XZ"
|
|
default y
|
|
select DECOMPRESS_XZ
|
|
help
|
|
Support loading of a XZ encoded initial ramdisk or cpio buffer.
|
|
If unsure, say N.
|
|
|
|
config RD_LZO
|
|
bool "Support initial ramdisk/ramfs compressed using LZO"
|
|
default y
|
|
select DECOMPRESS_LZO
|
|
help
|
|
Support loading of a LZO encoded initial ramdisk or cpio buffer
|
|
If unsure, say N.
|
|
|
|
config RD_LZ4
|
|
bool "Support initial ramdisk/ramfs compressed using LZ4"
|
|
default y
|
|
select DECOMPRESS_LZ4
|
|
help
|
|
Support loading of a LZ4 encoded initial ramdisk or cpio buffer
|
|
If unsure, say N.
|
|
|
|
choice
|
|
prompt "Built-in initramfs compression mode"
|
|
help
|
|
This option allows you to decide by which algorithm the builtin
|
|
initramfs will be compressed. Several compression algorithms are
|
|
available, which differ in efficiency, compression and
|
|
decompression speed. Compression speed is only relevant
|
|
when building a kernel. Decompression speed is relevant at
|
|
each boot. Also the memory usage during decompression may become
|
|
relevant on memory constrained systems. This is usually based on the
|
|
dictionary size of the algorithm with algorithms like XZ and LZMA
|
|
featuring large dictionary sizes.
|
|
|
|
High compression options are mostly useful for users who are
|
|
low on RAM, since it reduces the memory consumption during
|
|
boot.
|
|
|
|
Keep in mind that your build system needs to provide the appropriate
|
|
compression tool to compress the generated initram cpio file for
|
|
embedding.
|
|
|
|
If in doubt, select 'None'
|
|
|
|
config INITRAMFS_COMPRESSION_NONE
|
|
bool "None"
|
|
help
|
|
Do not compress the built-in initramfs at all. This may sound wasteful
|
|
in space, but, you should be aware that the built-in initramfs will be
|
|
compressed at a later stage anyways along with the rest of the kernel,
|
|
on those architectures that support this. However, not compressing the
|
|
initramfs may lead to slightly higher memory consumption during a
|
|
short time at boot, while both the cpio image and the unpacked
|
|
filesystem image will be present in memory simultaneously
|
|
|
|
config INITRAMFS_COMPRESSION_GZIP
|
|
bool "Gzip"
|
|
depends on RD_GZIP
|
|
help
|
|
Use the old and well tested gzip compression algorithm. Gzip provides
|
|
a good balance between compression ratio and decompression speed and
|
|
has a reasonable compression speed. It is also more likely to be
|
|
supported by your build system as the gzip tool is present by default
|
|
on most distros.
|
|
|
|
config INITRAMFS_COMPRESSION_BZIP2
|
|
bool "Bzip2"
|
|
depends on RD_BZIP2
|
|
help
|
|
It's compression ratio and speed is intermediate. Decompression speed
|
|
is slowest among the choices. The initramfs size is about 10% smaller
|
|
with bzip2, in comparison to gzip. Bzip2 uses a large amount of
|
|
memory. For modern kernels you will need at least 8MB RAM or more for
|
|
booting.
|
|
|
|
If you choose this, keep in mind that you need to have the bzip2 tool
|
|
available to be able to compress the initram.
|
|
|
|
config INITRAMFS_COMPRESSION_LZMA
|
|
bool "LZMA"
|
|
depends on RD_LZMA
|
|
help
|
|
This algorithm's compression ratio is best but has a large dictionary
|
|
size which might cause issues in memory constrained systems.
|
|
Decompression speed is between the other choices. Compression is
|
|
slowest. The initramfs size is about 33% smaller with LZMA in
|
|
comparison to gzip.
|
|
|
|
If you choose this, keep in mind that you may need to install the xz
|
|
or lzma tools to be able to compress the initram.
|
|
|
|
config INITRAMFS_COMPRESSION_XZ
|
|
bool "XZ"
|
|
depends on RD_XZ
|
|
help
|
|
XZ uses the LZMA2 algorithm and has a large dictionary which may cause
|
|
problems on memory constrained systems. The initramfs size is about
|
|
30% smaller with XZ in comparison to gzip. Decompression speed is
|
|
better than that of bzip2 but worse than gzip and LZO. Compression is
|
|
slow.
|
|
|
|
If you choose this, keep in mind that you may need to install the xz
|
|
tool to be able to compress the initram.
|
|
|
|
config INITRAMFS_COMPRESSION_LZO
|
|
bool "LZO"
|
|
depends on RD_LZO
|
|
help
|
|
It's compression ratio is the second poorest amongst the choices. The
|
|
kernel size is about 10% bigger than gzip. Despite that, it's
|
|
decompression speed is the second fastest and it's compression speed
|
|
is quite fast too.
|
|
|
|
If you choose this, keep in mind that you may need to install the lzop
|
|
tool to be able to compress the initram.
|
|
|
|
config INITRAMFS_COMPRESSION_LZ4
|
|
bool "LZ4"
|
|
depends on RD_LZ4
|
|
help
|
|
It's compression ratio is the poorest amongst the choices. The kernel
|
|
size is about 15% bigger than gzip; however its decompression speed
|
|
is the fastest.
|
|
|
|
If you choose this, keep in mind that most distros don't provide lz4
|
|
by default which could cause a build failure.
|
|
|
|
endchoice
|