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 75config RD_LZO 76 bool "Support initial ramdisks compressed using LZO" if EMBEDDED 77 default !EMBEDDED 78 depends on BLK_DEV_INITRD 79 select DECOMPRESS_LZO 80 help 81 Support loading of a LZO encoded initial ramdisk or cpio buffer 82 If unsure, say N. 83 84choice 85 prompt "Built-in initramfs compression mode" if INITRAMFS_SOURCE!="" 86 help 87 This option decides by which algorithm the builtin initramfs 88 will be compressed. Several compression algorithms are 89 available, which differ in efficiency, compression and 90 decompression speed. Compression speed is only relevant 91 when building a kernel. Decompression speed is relevant at 92 each boot. 93 94 If you have any problems with bzip2 or LZMA compressed 95 initramfs, mail me (Alain Knaff) <alain@knaff.lu>. 96 97 High compression options are mostly useful for users who are 98 low on RAM, since it reduces the memory consumption during 99 boot. 100 101 If in doubt, select 'gzip' 102 103config INITRAMFS_COMPRESSION_NONE 104 bool "None" 105 help 106 Do not compress the built-in initramfs at all. This may 107 sound wasteful in space, but, you should be aware that the 108 built-in initramfs will be compressed at a later stage 109 anyways along with the rest of the kernel, on those 110 architectures that support this. 111 However, not compressing the initramfs may lead to slightly 112 higher memory consumption during a short time at boot, while 113 both the cpio image and the unpacked filesystem image will 114 be present in memory simultaneously 115 116config INITRAMFS_COMPRESSION_GZIP 117 bool "Gzip" 118 depends on RD_GZIP 119 help 120 The old and tried gzip compression. It provides a good balance 121 between compression ratio and decompression speed. 122 123config INITRAMFS_COMPRESSION_BZIP2 124 bool "Bzip2" 125 depends on RD_BZIP2 126 help 127 Its compression ratio and speed is intermediate. 128 Decompression speed is slowest among the four. The initramfs 129 size is about 10% smaller with bzip2, in comparison to gzip. 130 Bzip2 uses a large amount of memory. For modern kernels you 131 will need at least 8MB RAM or more for booting. 132 133config INITRAMFS_COMPRESSION_LZMA 134 bool "LZMA" 135 depends on RD_LZMA 136 help 137 The most recent compression algorithm. 138 Its ratio is best, decompression speed is between the other 139 three. Compression is slowest. The initramfs size is about 33% 140 smaller with LZMA in comparison to gzip. 141 142config INITRAMFS_COMPRESSION_LZO 143 bool "LZO" 144 depends on RD_LZO 145 help 146 Its compression ratio is the poorest among the four. The kernel 147 size is about about 10% bigger than gzip; however its speed 148 (both compression and decompression) is the fastest. 149 150endchoice 151