1# 2# Configuration for initramfs 3# 4 5config INITRAMFS_SOURCE 6 string "Initramfs source file(s)" 7 default "" 8 help 9 This can be either a single cpio archive with a .cpio suffix or a 10 space-separated list of directories and files for building the 11 initramfs image. A cpio archive should contain a filesystem archive 12 to be used as an initramfs image. Directories should contain a 13 filesystem layout to be included in the initramfs image. Files 14 should contain entries according to the format described by the 15 "usr/gen_init_cpio" program in the kernel tree. 16 17 When multiple directories and files are specified then the 18 initramfs image will be the aggregate of all of them. 19 20 See <file:Documentation/early-userspace/README> for more details. 21 22 If you are not sure, leave it blank. 23 24config INITRAMFS_ROOT_UID 25 int "User ID to map to 0 (user root)" 26 depends on INITRAMFS_SOURCE!="" 27 default "0" 28 help 29 This setting is only meaningful if the INITRAMFS_SOURCE is 30 contains a directory. Setting this user ID (UID) to something 31 other than "0" will cause all files owned by that UID to be 32 owned by user root in the initial ramdisk image. 33 34 If you are not sure, leave it set to "0". 35 36config INITRAMFS_ROOT_GID 37 int "Group ID to map to 0 (group root)" 38 depends on INITRAMFS_SOURCE!="" 39 default "0" 40 help 41 This setting is only meaningful if the INITRAMFS_SOURCE is 42 contains a directory. Setting this group ID (GID) to something 43 other than "0" will cause all files owned by that GID to be 44 owned by group root in the initial ramdisk image. 45 46 If you are not sure, leave it set to "0". 47 48config RD_GZIP 49 bool "Support initial ramdisks compressed using gzip" if EMBEDDED 50 default y 51 depends on BLK_DEV_INITRD 52 select DECOMPRESS_GZIP 53 help 54 Support loading of a gzip encoded initial ramdisk or cpio buffer. 55 If unsure, say Y. 56 57config RD_BZIP2 58 bool "Support initial ramdisks compressed using bzip2" if EMBEDDED 59 default !EMBEDDED 60 depends on BLK_DEV_INITRD 61 select DECOMPRESS_BZIP2 62 help 63 Support loading of a bzip2 encoded initial ramdisk or cpio buffer 64 If unsure, say N. 65 66config RD_LZMA 67 bool "Support initial ramdisks compressed using LZMA" if EMBEDDED 68 default !EMBEDDED 69 depends on BLK_DEV_INITRD 70 select DECOMPRESS_LZMA 71 help 72 Support loading of a LZMA encoded initial ramdisk or cpio buffer 73 If unsure, say N. 74 75choice 76 prompt "Built-in initramfs compression mode" if INITRAMFS_SOURCE!="" 77 help 78 This option decides by which algorithm the builtin initramfs 79 will be compressed. Several compression algorithms are 80 available, which differ in efficiency, compression and 81 decompression speed. Compression speed is only relevant 82 when building a kernel. Decompression speed is relevant at 83 each boot. 84 85 If you have any problems with bzip2 or LZMA compressed 86 initramfs, mail me (Alain Knaff) <alain@knaff.lu>. 87 88 High compression options are mostly useful for users who are 89 low on RAM, since it reduces the memory consumption during 90 boot. 91 92 If in doubt, select 'gzip' 93 94config INITRAMFS_COMPRESSION_NONE 95 bool "None" 96 help 97 Do not compress the built-in initramfs at all. This may 98 sound wasteful in space, but, you should be aware that the 99 built-in initramfs will be compressed at a later stage 100 anyways along with the rest of the kernel, on those 101 architectures that support this. 102 However, not compressing the initramfs may lead to slightly 103 higher memory consumption during a short time at boot, while 104 both the cpio image and the unpacked filesystem image will 105 be present in memory simultaneously 106 107config INITRAMFS_COMPRESSION_GZIP 108 bool "Gzip" 109 depends on RD_GZIP 110 help 111 The old and tried gzip compression. Its compression ratio is 112 the poorest among the 3 choices; however its speed (both 113 compression and decompression) is the fastest. 114 115config INITRAMFS_COMPRESSION_BZIP2 116 bool "Bzip2" 117 depends on RD_BZIP2 118 help 119 Its compression ratio and speed is intermediate. 120 Decompression speed is slowest among the three. The initramfs 121 size is about 10% smaller with bzip2, in comparison to gzip. 122 Bzip2 uses a large amount of memory. For modern kernels you 123 will need at least 8MB RAM or more for booting. 124 125config INITRAMFS_COMPRESSION_LZMA 126 bool "LZMA" 127 depends on RD_LZMA 128 help 129 The most recent compression algorithm. 130 Its ratio is best, decompression speed is between the other 131 two. Compression is slowest. The initramfs size is about 33% 132 smaller with LZMA in comparison to gzip. 133 134endchoice 135