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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 | |
337bed41 | 49 | bool "Support initial ramdisks compressed using gzip" if EMBEDDED |
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 | |
337bed41 | 58 | bool "Support initial ramdisks compressed using bzip2" if EMBEDDED |
73d8a12f PA |
59 | default !EMBEDDED |
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 | |
55d1d26f | 67 | bool "Support initial ramdisks compressed using LZMA" if EMBEDDED |
73d8a12f PA |
68 | default !EMBEDDED |
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 AK |
74 | |
75 | choice | |
1359096e | 76 | prompt "Built-in initramfs compression mode" if INITRAMFS_SOURCE!="" |
ab76f3d7 | 77 | help |
40297927 PA |
78 | This option decides by which algorithm the builtin initramfs |
79 | will be compressed. Several compression algorithms are | |
80 | available, which differ in efficiency, compression and | |
81 | decompression speed. Compression speed is only relevant | |
82 | when building a kernel. Decompression speed is relevant at | |
83 | each boot. | |
ab76f3d7 | 84 | |
55d1d26f | 85 | If you have any problems with bzip2 or LZMA compressed |
ab76f3d7 AK |
86 | initramfs, mail me (Alain Knaff) <alain@knaff.lu>. |
87 | ||
40297927 PA |
88 | High compression options are mostly useful for users who are |
89 | low on RAM, since it reduces the memory consumption during | |
90 | boot. | |
ab76f3d7 AK |
91 | |
92 | If in doubt, select 'gzip' | |
93 | ||
94 | config INITRAMFS_COMPRESSION_NONE | |
95 | bool "None" | |
96 | help | |
97 | Do not compress the built-in initramfs at all. This may | |
98 | sound wasteful in space, but, you should be aware that the | |
99 | built-in initramfs will be compressed at a later stage | |
100 | anyways along with the rest of the kernel, on those | |
101 | architectures that support this. | |
102 | However, not compressing the initramfs may lead to slightly | |
103 | higher memory consumption during a short time at boot, while | |
104 | both the cpio image and the unpacked filesystem image will | |
105 | be present in memory simultaneously | |
106 | ||
107 | config INITRAMFS_COMPRESSION_GZIP | |
108 | bool "Gzip" | |
109 | depends on RD_GZIP | |
110 | help | |
111 | The old and tried gzip compression. Its compression ratio is | |
112 | the poorest among the 3 choices; however its speed (both | |
113 | compression and decompression) is the fastest. | |
114 | ||
115 | config INITRAMFS_COMPRESSION_BZIP2 | |
116 | bool "Bzip2" | |
117 | depends on RD_BZIP2 | |
118 | help | |
119 | Its compression ratio and speed is intermediate. | |
120 | Decompression speed is slowest among the three. The initramfs | |
121 | size is about 10% smaller with bzip2, in comparison to gzip. | |
122 | Bzip2 uses a large amount of memory. For modern kernels you | |
123 | will need at least 8MB RAM or more for booting. | |
124 | ||
125 | config INITRAMFS_COMPRESSION_LZMA | |
126 | bool "LZMA" | |
127 | depends on RD_LZMA | |
128 | help | |
129 | The most recent compression algorithm. | |
130 | Its ratio is best, decompression speed is between the other | |
131 | two. Compression is slowest. The initramfs size is about 33% | |
132 | smaller with LZMA in comparison to gzip. | |
133 | ||
134 | endchoice |