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 75if INITRAMFS_SOURCE!="" 76 77choice 78 prompt "Built-in initramfs compression mode" 79 help 80 This option decides by which algorithm the builtin initramfs 81 will be compressed. Several compression algorithms are 82 available, which differ in efficiency, compression and 83 decompression speed. Compression speed is only relevant 84 when building a kernel. Decompression speed is relevant at 85 each boot. 86 87 If you have any problems with bzip2 or LZMA compressed 88 initramfs, mail me (Alain Knaff) <alain@knaff.lu>. 89 90 High compression options are mostly useful for users who are 91 low on RAM, since it reduces the memory consumption during 92 boot. 93 94 If in doubt, select 'gzip' 95 96config INITRAMFS_COMPRESSION_NONE 97 bool "None" 98 help 99 Do not compress the built-in initramfs at all. This may 100 sound wasteful in space, but, you should be aware that the 101 built-in initramfs will be compressed at a later stage 102 anyways along with the rest of the kernel, on those 103 architectures that support this. 104 However, not compressing the initramfs may lead to slightly 105 higher memory consumption during a short time at boot, while 106 both the cpio image and the unpacked filesystem image will 107 be present in memory simultaneously 108 109config INITRAMFS_COMPRESSION_GZIP 110 bool "Gzip" 111 depends on RD_GZIP 112 help 113 The old and tried gzip compression. Its compression ratio is 114 the poorest among the 3 choices; however its speed (both 115 compression and decompression) is the fastest. 116 117config INITRAMFS_COMPRESSION_BZIP2 118 bool "Bzip2" 119 depends on RD_BZIP2 120 help 121 Its compression ratio and speed is intermediate. 122 Decompression speed is slowest among the three. The initramfs 123 size is about 10% smaller with bzip2, in comparison to gzip. 124 Bzip2 uses a large amount of memory. For modern kernels you 125 will need at least 8MB RAM or more for booting. 126 127config INITRAMFS_COMPRESSION_LZMA 128 bool "LZMA" 129 depends on RD_LZMA 130 help 131 The most recent compression algorithm. 132 Its ratio is best, decompression speed is between the other 133 two. Compression is slowest. The initramfs size is about 33% 134 smaller with LZMA in comparison to gzip. 135 136endchoice 137 138endif 139 140if INITRAMFS_SOURCE="" 141# The builtin initramfs is so small so we don't want to bug the user... 142 143config INITRAMFS_COMPRESSION_NONE 144 bool 145 default y 146 147endif 148