2005-08-10 12:44:50 -06:00
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#
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# Configuration for initramfs
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#
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config INITRAMFS_SOURCE
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string "Initramfs source file(s)"
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default ""
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help
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This can be either a single cpio archive with a .cpio suffix or a
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space-separated list of directories and files for building the
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initramfs image. A cpio archive should contain a filesystem archive
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to be used as an initramfs image. Directories should contain a
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filesystem layout to be included in the initramfs image. Files
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should contain entries according to the format described by the
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"usr/gen_init_cpio" program in the kernel tree.
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When multiple directories and files are specified then the
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initramfs image will be the aggregate of all of them.
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2007-03-16 07:01:45 -06:00
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See <file:Documentation/early-userspace/README> for more details.
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2005-08-10 12:44:50 -06:00
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If you are not sure, leave it blank.
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2017-05-08 16:56:57 -06:00
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config INITRAMFS_FORCE
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bool "Ignore the initramfs passed by the bootloader"
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depends on CMDLINE_EXTEND || CMDLINE_FORCE
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help
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This option causes the kernel to ignore the initramfs image
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(or initrd image) passed to it by the bootloader. This is
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analogous to CMDLINE_FORCE, which is found on some architectures,
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and is useful if you cannot or don't want to change the image
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your bootloader passes to the kernel.
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2005-08-10 12:44:50 -06:00
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config INITRAMFS_ROOT_UID
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int "User ID to map to 0 (user root)"
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depends on INITRAMFS_SOURCE!=""
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default "0"
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help
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This setting is only meaningful if the INITRAMFS_SOURCE is
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contains a directory. Setting this user ID (UID) to something
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other than "0" will cause all files owned by that UID to be
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owned by user root in the initial ramdisk image.
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If you are not sure, leave it set to "0".
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config INITRAMFS_ROOT_GID
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int "Group ID to map to 0 (group root)"
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depends on INITRAMFS_SOURCE!=""
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default "0"
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help
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This setting is only meaningful if the INITRAMFS_SOURCE is
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contains a directory. Setting this group ID (GID) to something
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other than "0" will cause all files owned by that GID to be
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owned by group root in the initial ramdisk image.
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If you are not sure, leave it set to "0".
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2009-01-07 01:03:49 -07:00
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config RD_GZIP
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2014-12-12 17:58:03 -07:00
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bool "Support initial ramdisks compressed using gzip"
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2009-03-28 16:49:08 -06:00
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depends on BLK_DEV_INITRD
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2014-12-12 17:58:03 -07:00
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default y
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2009-01-07 01:03:49 -07:00
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select DECOMPRESS_GZIP
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help
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Support loading of a gzip encoded initial ramdisk or cpio buffer.
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If unsure, say Y.
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config RD_BZIP2
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2014-12-12 17:58:03 -07:00
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bool "Support initial ramdisks compressed using bzip2"
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default y
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2009-03-28 16:49:08 -06:00
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depends on BLK_DEV_INITRD
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2009-01-07 01:03:49 -07:00
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select DECOMPRESS_BZIP2
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help
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Support loading of a bzip2 encoded initial ramdisk or cpio buffer
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If unsure, say N.
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config RD_LZMA
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2014-12-12 17:58:03 -07:00
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bool "Support initial ramdisks compressed using LZMA"
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default y
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2009-03-28 16:49:08 -06:00
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depends on BLK_DEV_INITRD
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2009-01-07 01:03:49 -07:00
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select DECOMPRESS_LZMA
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help
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2009-03-28 17:10:59 -06:00
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Support loading of a LZMA encoded initial ramdisk or cpio buffer
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2009-01-07 01:03:49 -07:00
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If unsure, say N.
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2009-02-19 14:43:51 -07:00
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decompressors: add boot-time XZ support
This implements the API defined in <linux/decompress/generic.h> which is
used for kernel, initramfs, and initrd decompression. This patch together
with the first patch is enough for XZ-compressed initramfs and initrd;
XZ-compressed kernel will need arch-specific changes.
The buffering requirements described in decompress_unxz.c are stricter
than with gzip, so the relevant changes should be done to the
arch-specific code when adding support for XZ-compressed kernel.
Similarly, the heap size in arch-specific pre-boot code may need to be
increased (30 KiB is enough).
The XZ decompressor needs memmove(), memeq() (memcmp() == 0), and
memzero() (memset(ptr, 0, size)), which aren't available in all
arch-specific pre-boot environments. I'm including simple versions in
decompress_unxz.c, but a cleaner solution would naturally be nicer.
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alain Knaff <alain@knaff.lu>
Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-12 18:01:23 -07:00
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config RD_XZ
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2014-12-12 17:58:03 -07:00
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bool "Support initial ramdisks compressed using XZ"
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decompressors: add boot-time XZ support
This implements the API defined in <linux/decompress/generic.h> which is
used for kernel, initramfs, and initrd decompression. This patch together
with the first patch is enough for XZ-compressed initramfs and initrd;
XZ-compressed kernel will need arch-specific changes.
The buffering requirements described in decompress_unxz.c are stricter
than with gzip, so the relevant changes should be done to the
arch-specific code when adding support for XZ-compressed kernel.
Similarly, the heap size in arch-specific pre-boot code may need to be
increased (30 KiB is enough).
The XZ decompressor needs memmove(), memeq() (memcmp() == 0), and
memzero() (memset(ptr, 0, size)), which aren't available in all
arch-specific pre-boot environments. I'm including simple versions in
decompress_unxz.c, but a cleaner solution would naturally be nicer.
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alain Knaff <alain@knaff.lu>
Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-12 18:01:23 -07:00
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depends on BLK_DEV_INITRD
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2014-12-12 17:58:03 -07:00
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default y
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decompressors: add boot-time XZ support
This implements the API defined in <linux/decompress/generic.h> which is
used for kernel, initramfs, and initrd decompression. This patch together
with the first patch is enough for XZ-compressed initramfs and initrd;
XZ-compressed kernel will need arch-specific changes.
The buffering requirements described in decompress_unxz.c are stricter
than with gzip, so the relevant changes should be done to the
arch-specific code when adding support for XZ-compressed kernel.
Similarly, the heap size in arch-specific pre-boot code may need to be
increased (30 KiB is enough).
The XZ decompressor needs memmove(), memeq() (memcmp() == 0), and
memzero() (memset(ptr, 0, size)), which aren't available in all
arch-specific pre-boot environments. I'm including simple versions in
decompress_unxz.c, but a cleaner solution would naturally be nicer.
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alain Knaff <alain@knaff.lu>
Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-12 18:01:23 -07:00
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select DECOMPRESS_XZ
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help
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Support loading of a XZ encoded initial ramdisk or cpio buffer.
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If unsure, say N.
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2010-01-08 15:42:46 -07:00
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config RD_LZO
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2014-12-12 17:58:03 -07:00
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bool "Support initial ramdisks compressed using LZO"
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default y
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2010-01-08 15:42:46 -07:00
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depends on BLK_DEV_INITRD
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select DECOMPRESS_LZO
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help
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Support loading of a LZO encoded initial ramdisk or cpio buffer
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If unsure, say N.
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2013-07-08 17:01:46 -06:00
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config RD_LZ4
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2014-12-12 17:58:03 -07:00
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bool "Support initial ramdisks compressed using LZ4"
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default y
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2013-07-08 17:01:46 -06:00
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depends on BLK_DEV_INITRD
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select DECOMPRESS_LZ4
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help
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Support loading of a LZ4 encoded initial ramdisk or cpio buffer
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If unsure, say N.
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2016-12-14 16:06:01 -07:00
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2016-12-14 16:06:04 -07:00
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choice
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prompt "Built-in initramfs compression mode"
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depends on INITRAMFS_SOURCE!=""
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optional
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help
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This option allows you to decide by which algorithm the builtin
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initramfs will be compressed. Several compression algorithms are
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available, which differ in efficiency, compression and
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decompression speed. Compression speed is only relevant
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when building a kernel. Decompression speed is relevant at
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each boot. Also the memory usage during decompression may become
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relevant on memory constrained systems. This is usually based on the
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dictionary size of the algorithm with algorithms like XZ and LZMA
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featuring large dictionary sizes.
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High compression options are mostly useful for users who are
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low on RAM, since it reduces the memory consumption during
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boot.
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Keep in mind that your build system needs to provide the appropriate
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compression tool to compress the generated initram cpio file for
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embedding.
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If in doubt, select 'None'
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config INITRAMFS_COMPRESSION_NONE
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bool "None"
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help
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Do not compress the built-in initramfs at all. This may sound wasteful
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in space, but, you should be aware that the built-in initramfs will be
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compressed at a later stage anyways along with the rest of the kernel,
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on those architectures that support this. However, not compressing the
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initramfs may lead to slightly higher memory consumption during a
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short time at boot, while both the cpio image and the unpacked
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filesystem image will be present in memory simultaneously
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config INITRAMFS_COMPRESSION_GZIP
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bool "Gzip"
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depends on RD_GZIP
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help
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Use the old and well tested gzip compression algorithm. Gzip provides
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a good balance between compression ratio and decompression speed and
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has a reasonable compression speed. It is also more likely to be
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supported by your build system as the gzip tool is present by default
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on most distros.
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config INITRAMFS_COMPRESSION_BZIP2
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bool "Bzip2"
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depends on RD_BZIP2
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help
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It's compression ratio and speed is intermediate. Decompression speed
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is slowest among the choices. The initramfs size is about 10% smaller
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with bzip2, in comparison to gzip. Bzip2 uses a large amount of
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memory. For modern kernels you will need at least 8MB RAM or more for
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booting.
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If you choose this, keep in mind that you need to have the bzip2 tool
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available to be able to compress the initram.
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config INITRAMFS_COMPRESSION_LZMA
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bool "LZMA"
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depends on RD_LZMA
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help
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This algorithm's compression ratio is best but has a large dictionary
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size which might cause issues in memory constrained systems.
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Decompression speed is between the other choices. Compression is
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slowest. The initramfs size is about 33% smaller with LZMA in
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comparison to gzip.
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If you choose this, keep in mind that you may need to install the xz
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or lzma tools to be able to compress the initram.
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config INITRAMFS_COMPRESSION_XZ
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bool "XZ"
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depends on RD_XZ
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help
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XZ uses the LZMA2 algorithm and has a large dictionary which may cause
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problems on memory constrained systems. The initramfs size is about
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30% smaller with XZ in comparison to gzip. Decompression speed is
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better than that of bzip2 but worse than gzip and LZO. Compression is
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slow.
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If you choose this, keep in mind that you may need to install the xz
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tool to be able to compress the initram.
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config INITRAMFS_COMPRESSION_LZO
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bool "LZO"
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depends on RD_LZO
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help
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It's compression ratio is the second poorest amongst the choices. The
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kernel size is about 10% bigger than gzip. Despite that, it's
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decompression speed is the second fastest and it's compression speed
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is quite fast too.
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If you choose this, keep in mind that you may need to install the lzop
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tool to be able to compress the initram.
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config INITRAMFS_COMPRESSION_LZ4
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bool "LZ4"
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depends on RD_LZ4
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help
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It's compression ratio is the poorest amongst the choices. The kernel
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size is about 15% bigger than gzip; however its decompression speed
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is the fastest.
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If you choose this, keep in mind that most distros don't provide lz4
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by default which could cause a build failure.
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endchoice
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2016-12-14 16:06:01 -07:00
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config INITRAMFS_COMPRESSION
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initramfs: fix disabling of initramfs (and its compression)
Commit db2aa7fd15e8 ("initramfs: allow again choice of the embedded
initram compression algorithm") introduced the possibility to select the
initramfs compression algorithm from Kconfig and while this is a nice
feature it broke the use case described below.
Here is what my build system does:
- kernel is initially configured not to have an initramfs included
- build the user space root file system
- re-configure the kernel to have an initramfs included
(CONFIG_INITRAMFS_SOURCE="/path/to/romfs") and set relevant
CONFIG_INITRAMFS options, in my case, no compression option
(CONFIG_INITRAMFS_COMPRESSION_NONE)
- kernel is re-built with these options -> kernel+initramfs image is
copied
- kernel is re-built again without these options -> kernel image is
copied
Building a kernel without an initramfs means setting this option:
CONFIG_INITRAMFS_SOURCE="" (and this one only)
whereas building a kernel with an initramfs means setting these options:
CONFIG_INITRAMFS_SOURCE="/home/fainelli/work/uclinux-rootfs/romfs /home/fainelli/work/uclinux-rootfs/misc/initramfs.dev"
CONFIG_INITRAMFS_ROOT_UID=1000
CONFIG_INITRAMFS_ROOT_GID=1000
CONFIG_INITRAMFS_COMPRESSION_NONE=y
CONFIG_INITRAMFS_COMPRESSION=""
Commit db2aa7fd15e85 ("initramfs: allow again choice of the embedded
initram compression algorithm") is problematic because
CONFIG_INITRAMFS_COMPRESSION which is used to determine the
initramfs_data.cpio extension/compression is a string, and due to how
Kconfig works it will evaluate in order, how to assign it.
Setting CONFIG_INITRAMFS_COMPRESSION_NONE with CONFIG_INITRAMFS_SOURCE=""
cannot possibly work (because of the depends on INITRAMFS_SOURCE!=""
imposed on CONFIG_INITRAMFS_COMPRESSION ) yet we still get
CONFIG_INITRAMFS_COMPRESSION assigned to ".gz" because CONFIG_RD_GZIP=y
is set in my kernel, even when there is no initramfs being built.
So we basically end-up generating two initramfs_data.cpio* files, one
without extension, and one with .gz. This causes usr/Makefile to track
usr/initramfs_data.cpio.gz, and not usr/initramfs_data.cpio anymore,
that is also largely problematic after 9e3596b0c6539e ("kbuild:
initramfs cleanup, set target from Kconfig") because we used to track
all possible initramfs_data files in the $(targets) variable before that
commit.
The end result is that the kernel with an initramfs clearly does not
contain what we expect it to, it has a stale initramfs_data.cpio file
built into it, and we keep re-generating an initramfs_data.cpio.gz file
which is not the one that we want to include in the kernel image proper.
The fix consists in hiding CONFIG_INITRAMFS_COMPRESSION when
CONFIG_INITRAMFS_SOURCE="". This puts us back in a state to the
pre-4.10 behavior where we can properly disable and re-enable initramfs
within the same kernel .config file, and be in control of what
CONFIG_INITRAMFS_COMPRESSION is set to.
Fixes: db2aa7fd15e8 ("initramfs: allow again choice of the embedded initram compression algorithm")
Fixes: 9e3596b0c653 ("kbuild: initramfs cleanup, set target from Kconfig")
Link: http://lkml.kernel.org/r/20170521033337.6197-1-f.fainelli@gmail.com
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
Cc: P J P <ppandit@redhat.com>
Cc: Paul Bolle <pebolle@tiscali.nl>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-02 15:46:22 -06:00
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depends on INITRAMFS_SOURCE!=""
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2016-12-14 16:06:01 -07:00
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string
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2016-12-14 16:06:04 -07:00
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default "" if INITRAMFS_COMPRESSION_NONE
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default ".gz" if INITRAMFS_COMPRESSION_GZIP
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default ".bz2" if INITRAMFS_COMPRESSION_BZIP2
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default ".lzma" if INITRAMFS_COMPRESSION_LZMA
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default ".xz" if INITRAMFS_COMPRESSION_XZ
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default ".lzo" if INITRAMFS_COMPRESSION_LZO
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default ".lz4" if INITRAMFS_COMPRESSION_LZ4
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2016-12-14 16:06:01 -07:00
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default ".gz" if RD_GZIP
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default ".lz4" if RD_LZ4
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default ".lzo" if RD_LZO
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default ".xz" if RD_XZ
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default ".lzma" if RD_LZMA
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default ".bz2" if RD_BZIP2
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default ""
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