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dbec4866 SR |
1 | # |
2 | # Configuration for initramfs | |
3 | # | |
4 | ||
5 | config 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 | ||
0979f378 | 20 | See <file:Documentation/early-userspace/README> for more details. |
dbec4866 SR |
21 | |
22 | If you are not sure, leave it blank. | |
23 | ||
24 | config 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 | ||
36 | config 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". | |
fb9a4ca9 PA |
47 | |
48 | config RD_GZIP | |
6a108a14 | 49 | bool "Support initial ramdisks compressed using gzip" if EXPERT |
fb9a4ca9 | 50 | default y |
73d8a12f | 51 | depends on BLK_DEV_INITRD |
fb9a4ca9 PA |
52 | select DECOMPRESS_GZIP |
53 | help | |
54 | Support loading of a gzip encoded initial ramdisk or cpio buffer. | |
55 | If unsure, say Y. | |
56 | ||
57 | config RD_BZIP2 | |
6a108a14 DR |
58 | bool "Support initial ramdisks compressed using bzip2" if EXPERT |
59 | default !EXPERT | |
73d8a12f | 60 | depends on BLK_DEV_INITRD |
fb9a4ca9 PA |
61 | select DECOMPRESS_BZIP2 |
62 | help | |
63 | Support loading of a bzip2 encoded initial ramdisk or cpio buffer | |
64 | If unsure, say N. | |
65 | ||
66 | config RD_LZMA | |
6a108a14 DR |
67 | bool "Support initial ramdisks compressed using LZMA" if EXPERT |
68 | default !EXPERT | |
73d8a12f | 69 | depends on BLK_DEV_INITRD |
fb9a4ca9 PA |
70 | select DECOMPRESS_LZMA |
71 | help | |
55d1d26f | 72 | Support loading of a LZMA encoded initial ramdisk or cpio buffer |
fb9a4ca9 | 73 | If unsure, say N. |
ab76f3d7 | 74 | |
3ebe1243 | 75 | config RD_XZ |
6a108a14 DR |
76 | bool "Support initial ramdisks compressed using XZ" if EXPERT |
77 | default !EXPERT | |
3ebe1243 LC |
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 | ||
cacb246f | 84 | config RD_LZO |
6a108a14 DR |
85 | bool "Support initial ramdisks compressed using LZO" if EXPERT |
86 | default !EXPERT | |
cacb246f AT |
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 | ||
e76e1fdf KL |
93 | config RD_LZ4 |
94 | bool "Support initial ramdisks compressed using LZ4" if EXPERT | |
95 | default !EXPERT | |
96 | depends on BLK_DEV_INITRD | |
97 | select DECOMPRESS_LZ4 | |
98 | help | |
99 | Support loading of a LZ4 encoded initial ramdisk or cpio buffer | |
100 | If unsure, say N. | |
101 | ||
ab76f3d7 | 102 | choice |
1359096e | 103 | prompt "Built-in initramfs compression mode" if INITRAMFS_SOURCE!="" |
ab76f3d7 | 104 | help |
40297927 PA |
105 | This option decides by which algorithm the builtin initramfs |
106 | will be compressed. Several compression algorithms are | |
107 | available, which differ in efficiency, compression and | |
108 | decompression speed. Compression speed is only relevant | |
109 | when building a kernel. Decompression speed is relevant at | |
110 | each boot. | |
ab76f3d7 | 111 | |
55d1d26f | 112 | If you have any problems with bzip2 or LZMA compressed |
ab76f3d7 AK |
113 | initramfs, mail me (Alain Knaff) <[email protected]>. |
114 | ||
40297927 PA |
115 | High compression options are mostly useful for users who are |
116 | low on RAM, since it reduces the memory consumption during | |
117 | boot. | |
ab76f3d7 AK |
118 | |
119 | If in doubt, select 'gzip' | |
120 | ||
121 | config INITRAMFS_COMPRESSION_NONE | |
122 | bool "None" | |
123 | help | |
124 | Do not compress the built-in initramfs at all. This may | |
125 | sound wasteful in space, but, you should be aware that the | |
126 | built-in initramfs will be compressed at a later stage | |
127 | anyways along with the rest of the kernel, on those | |
128 | architectures that support this. | |
129 | However, not compressing the initramfs may lead to slightly | |
130 | higher memory consumption during a short time at boot, while | |
131 | both the cpio image and the unpacked filesystem image will | |
132 | be present in memory simultaneously | |
133 | ||
134 | config INITRAMFS_COMPRESSION_GZIP | |
135 | bool "Gzip" | |
136 | depends on RD_GZIP | |
137 | help | |
cacb246f AT |
138 | The old and tried gzip compression. It provides a good balance |
139 | between compression ratio and decompression speed. | |
ab76f3d7 AK |
140 | |
141 | config INITRAMFS_COMPRESSION_BZIP2 | |
142 | bool "Bzip2" | |
143 | depends on RD_BZIP2 | |
144 | help | |
145 | Its compression ratio and speed is intermediate. | |
0a4dd35c | 146 | Decompression speed is slowest among the choices. The initramfs |
ab76f3d7 AK |
147 | size is about 10% smaller with bzip2, in comparison to gzip. |
148 | Bzip2 uses a large amount of memory. For modern kernels you | |
149 | will need at least 8MB RAM or more for booting. | |
150 | ||
151 | config INITRAMFS_COMPRESSION_LZMA | |
152 | bool "LZMA" | |
153 | depends on RD_LZMA | |
154 | help | |
0a4dd35c RD |
155 | This algorithm's compression ratio is best. |
156 | Decompression speed is between the other choices. | |
157 | Compression is slowest. The initramfs size is about 33% | |
ab76f3d7 AK |
158 | smaller with LZMA in comparison to gzip. |
159 | ||
3ebe1243 LC |
160 | config INITRAMFS_COMPRESSION_XZ |
161 | bool "XZ" | |
162 | depends on RD_XZ | |
163 | help | |
164 | XZ uses the LZMA2 algorithm. The initramfs size is about 30% | |
165 | smaller with XZ in comparison to gzip. Decompression speed | |
166 | is better than that of bzip2 but worse than gzip and LZO. | |
167 | Compression is slow. | |
168 | ||
cacb246f AT |
169 | config INITRAMFS_COMPRESSION_LZO |
170 | bool "LZO" | |
171 | depends on RD_LZO | |
172 | help | |
0a4dd35c | 173 | Its compression ratio is the poorest among the choices. The kernel |
681b3049 | 174 | size is about 10% bigger than gzip; however its speed |
cacb246f AT |
175 | (both compression and decompression) is the fastest. |
176 | ||
ab76f3d7 | 177 | endchoice |