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" 77 help 78 This setting is only meaningful if the INITRAMFS_SOURCE is 79 set. It decides by which algorithm the INITRAMFS_SOURCE will 80 be compressed. 81 Several compression algorithms are available, which differ 82 in efficiency, compression and decompression speed. 83 Compression speed is only relevant when building a kernel. 84 Decompression speed is relevant at each boot. 85 86 If you have any problems with bzip2 or lzma compressed 87 initramfs, mail me (Alain Knaff) <alain@knaff.lu>. 88 89 High compression options are mostly useful for users who 90 are low on disk space (embedded systems), but for whom ram 91 size matters less. 92 93 If in doubt, select 'gzip' 94 95config INITRAMFS_COMPRESSION_NONE 96 bool "None" 97 help 98 Do not compress the built-in initramfs at all. This may 99 sound wasteful in space, but, you should be aware that the 100 built-in initramfs will be compressed at a later stage 101 anyways along with the rest of the kernel, on those 102 architectures that support this. 103 However, not compressing the initramfs may lead to slightly 104 higher memory consumption during a short time at boot, while 105 both the cpio image and the unpacked filesystem image will 106 be present in memory simultaneously 107 108config INITRAMFS_COMPRESSION_GZIP 109 bool "Gzip" 110 depends on RD_GZIP 111 help 112 The old and tried gzip compression. Its compression ratio is 113 the poorest among the 3 choices; however its speed (both 114 compression and decompression) is the fastest. 115 116config INITRAMFS_COMPRESSION_BZIP2 117 bool "Bzip2" 118 depends on RD_BZIP2 119 help 120 Its compression ratio and speed is intermediate. 121 Decompression speed is slowest among the three. The initramfs 122 size is about 10% smaller with bzip2, in comparison to gzip. 123 Bzip2 uses a large amount of memory. For modern kernels you 124 will need at least 8MB RAM or more for booting. 125 126config INITRAMFS_COMPRESSION_LZMA 127 bool "LZMA" 128 depends on RD_LZMA 129 help 130 The most recent compression algorithm. 131 Its ratio is best, decompression speed is between the other 132 two. Compression is slowest. The initramfs size is about 33% 133 smaller with LZMA in comparison to gzip. 134 135endchoice 136