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- #
- # 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/early-userspace/README> for more details.
- If you are not sure, leave it blank.
- config INITRAMFS_ROOT_UID
- int "User ID to map to 0 (user root)"
- depends on INITRAMFS_SOURCE!=""
- default "0"
- help
- This setting is only meaningful if the INITRAMFS_SOURCE is
- contains a directory. Setting this user ID (UID) to something
- other than "0" will cause all files owned by that UID to be
- owned by user root in the initial ramdisk 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
- This setting is only meaningful if the INITRAMFS_SOURCE is
- contains a directory. Setting this group ID (GID) to something
- other than "0" will cause all files owned by that GID to be
- owned by group root in the initial ramdisk image.
- If you are not sure, leave it set to "0".
- config RD_GZIP
- bool "Support initial ramdisks compressed using gzip" if EXPERT
- default y
- depends on BLK_DEV_INITRD
- 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 ramdisks compressed using bzip2" if EXPERT
- default !EXPERT
- depends on BLK_DEV_INITRD
- 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 ramdisks compressed using LZMA" if EXPERT
- default !EXPERT
- depends on BLK_DEV_INITRD
- 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 ramdisks compressed using XZ" if EXPERT
- default !EXPERT
- depends on BLK_DEV_INITRD
- 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 ramdisks compressed using LZO" if EXPERT
- default !EXPERT
- depends on BLK_DEV_INITRD
- select DECOMPRESS_LZO
- help
- Support loading of a LZO encoded initial ramdisk or cpio buffer
- If unsure, say N.
- choice
- prompt "Built-in initramfs compression mode" if INITRAMFS_SOURCE!=""
- help
- This option decides 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.
- If you have any problems with bzip2 or LZMA compressed
- initramfs, mail me (Alain Knaff) <alain@knaff.lu>.
- High compression options are mostly useful for users who are
- low on RAM, since it reduces the memory consumption during
- boot.
- If in doubt, select 'gzip'
- 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
- The old and tried gzip compression. It provides a good balance
- between compression ratio and decompression speed.
- config INITRAMFS_COMPRESSION_BZIP2
- bool "Bzip2"
- depends on RD_BZIP2
- help
- Its compression ratio and speed is intermediate.
- Decompression speed is slowest among the four. 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.
- config INITRAMFS_COMPRESSION_LZMA
- bool "LZMA"
- depends on RD_LZMA
- help
- The most recent compression algorithm.
- Its ratio is best, decompression speed is between the other
- three. Compression is slowest. The initramfs size is about 33%
- smaller with LZMA in comparison to gzip.
- config INITRAMFS_COMPRESSION_XZ
- bool "XZ"
- depends on RD_XZ
- help
- XZ uses the LZMA2 algorithm. 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.
- config INITRAMFS_COMPRESSION_LZO
- bool "LZO"
- depends on RD_LZO
- help
- Its compression ratio is the poorest among the four. The kernel
- size is about 10% bigger than gzip; however its speed
- (both compression and decompression) is the fastest.
- endchoice
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