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