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 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