1
2
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 EXPERT
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 EXPERT
59 default !EXPERT
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 EXPERT
68 default !EXPERT
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_XZ
76 bool "Support initial ramdisks compressed using XZ" if EXPERT
77 default !EXPERT
78 depends on BLK_DEV_INITRD
79 select DECOMPRESS_XZ
80 help
81 Support loading of a XZ encoded initial ramdisk or cpio buffer.
82 If unsure, say N.
83
84config RD_LZO
85 bool "Support initial ramdisks compressed using LZO" if EXPERT
86 default !EXPERT
87 depends on BLK_DEV_INITRD
88 select DECOMPRESS_LZO
89 help
90 Support loading of a LZO encoded initial ramdisk or cpio buffer
91 If unsure, say N.
92
93choice
94 prompt "Built-in initramfs compression mode" if INITRAMFS_SOURCE!=""
95 help
96 This option decides by which algorithm the builtin initramfs
97 will be compressed. Several compression algorithms are
98 available, which differ in efficiency, compression and
99 decompression speed. Compression speed is only relevant
100 when building a kernel. Decompression speed is relevant at
101 each boot.
102
103 If you have any problems with bzip2 or LZMA compressed
104 initramfs, mail me (Alain Knaff) <alain@knaff.lu>.
105
106 High compression options are mostly useful for users who are
107 low on RAM, since it reduces the memory consumption during
108 boot.
109
110 If in doubt, select 'gzip'
111
112config INITRAMFS_COMPRESSION_NONE
113 bool "None"
114 help
115 Do not compress the built-in initramfs at all. This may
116 sound wasteful in space, but, you should be aware that the
117 built-in initramfs will be compressed at a later stage
118 anyways along with the rest of the kernel, on those
119 architectures that support this.
120 However, not compressing the initramfs may lead to slightly
121 higher memory consumption during a short time at boot, while
122 both the cpio image and the unpacked filesystem image will
123 be present in memory simultaneously
124
125config INITRAMFS_COMPRESSION_GZIP
126 bool "Gzip"
127 depends on RD_GZIP
128 help
129 The old and tried gzip compression. It provides a good balance
130 between compression ratio and decompression speed.
131
132config INITRAMFS_COMPRESSION_BZIP2
133 bool "Bzip2"
134 depends on RD_BZIP2
135 help
136 Its compression ratio and speed is intermediate.
137 Decompression speed is slowest among the four. The initramfs
138 size is about 10% smaller with bzip2, in comparison to gzip.
139 Bzip2 uses a large amount of memory. For modern kernels you
140 will need at least 8MB RAM or more for booting.
141
142config INITRAMFS_COMPRESSION_LZMA
143 bool "LZMA"
144 depends on RD_LZMA
145 help
146 The most recent compression algorithm.
147 Its ratio is best, decompression speed is between the other
148 three. Compression is slowest. The initramfs size is about 33%
149 smaller with LZMA in comparison to gzip.
150
151config INITRAMFS_COMPRESSION_XZ
152 bool "XZ"
153 depends on RD_XZ
154 help
155 XZ uses the LZMA2 algorithm. The initramfs size is about 30%
156 smaller with XZ in comparison to gzip. Decompression speed
157 is better than that of bzip2 but worse than gzip and LZO.
158 Compression is slow.
159
160config INITRAMFS_COMPRESSION_LZO
161 bool "LZO"
162 depends on RD_LZO
163 help
164 Its compression ratio is the poorest among the four. The kernel
165 size is about 10% bigger than gzip; however its speed
166 (both compression and decompression) is the fastest.
167
168endchoice
169
