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Sam Ravnborgdbec4862005-08-10 20:44:50 +02001#
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
Alexander E. Patrakov0979f372007-03-16 18:01:45 +050020 See <file:Documentation/early-userspace/README> for more details.
Sam Ravnborgdbec4862005-08-10 20:44:50 +020021
22 If you are not sure, leave it blank.
23
Daniel Thompsoncff75e02017-05-08 15:56:57 -070024config INITRAMFS_FORCE
25 bool "Ignore the initramfs passed by the bootloader"
26 depends on CMDLINE_EXTEND || CMDLINE_FORCE
27 help
28 This option causes the kernel to ignore the initramfs image
29 (or initrd image) passed to it by the bootloader. This is
30 analogous to CMDLINE_FORCE, which is found on some architectures,
31 and is useful if you cannot or don't want to change the image
32 your bootloader passes to the kernel.
33
Sam Ravnborgdbec4862005-08-10 20:44:50 +020034config INITRAMFS_ROOT_UID
35 int "User ID to map to 0 (user root)"
36 depends on INITRAMFS_SOURCE!=""
37 default "0"
38 help
39 This setting is only meaningful if the INITRAMFS_SOURCE is
40 contains a directory. Setting this user ID (UID) to something
41 other than "0" will cause all files owned by that UID to be
42 owned by user root in the initial ramdisk image.
43
44 If you are not sure, leave it set to "0".
45
46config INITRAMFS_ROOT_GID
47 int "Group ID to map to 0 (group root)"
48 depends on INITRAMFS_SOURCE!=""
49 default "0"
50 help
51 This setting is only meaningful if the INITRAMFS_SOURCE is
52 contains a directory. Setting this group ID (GID) to something
53 other than "0" will cause all files owned by that GID to be
54 owned by group root in the initial ramdisk image.
55
56 If you are not sure, leave it set to "0".
H. Peter Anvinfb9a4ca2009-01-07 00:03:49 -080057
58config RD_GZIP
Andi Kleenec72c662014-12-12 16:58:03 -080059 bool "Support initial ramdisks compressed using gzip"
H. Peter Anvin73d8a122009-03-28 15:49:08 -070060 depends on BLK_DEV_INITRD
Andi Kleenec72c662014-12-12 16:58:03 -080061 default y
H. Peter Anvinfb9a4ca2009-01-07 00:03:49 -080062 select DECOMPRESS_GZIP
63 help
64 Support loading of a gzip encoded initial ramdisk or cpio buffer.
65 If unsure, say Y.
66
67config RD_BZIP2
Andi Kleenec72c662014-12-12 16:58:03 -080068 bool "Support initial ramdisks compressed using bzip2"
69 default y
H. Peter Anvin73d8a122009-03-28 15:49:08 -070070 depends on BLK_DEV_INITRD
H. Peter Anvinfb9a4ca2009-01-07 00:03:49 -080071 select DECOMPRESS_BZIP2
72 help
73 Support loading of a bzip2 encoded initial ramdisk or cpio buffer
74 If unsure, say N.
75
76config RD_LZMA
Andi Kleenec72c662014-12-12 16:58:03 -080077 bool "Support initial ramdisks compressed using LZMA"
78 default y
H. Peter Anvin73d8a122009-03-28 15:49:08 -070079 depends on BLK_DEV_INITRD
H. Peter Anvinfb9a4ca2009-01-07 00:03:49 -080080 select DECOMPRESS_LZMA
81 help
H. Peter Anvin55d1d262009-03-28 16:10:59 -070082 Support loading of a LZMA encoded initial ramdisk or cpio buffer
H. Peter Anvinfb9a4ca2009-01-07 00:03:49 -080083 If unsure, say N.
Alain Knaffab76f3d2009-02-19 13:43:51 -080084
Lasse Collin3ebe1242011-01-12 17:01:23 -080085config RD_XZ
Andi Kleenec72c662014-12-12 16:58:03 -080086 bool "Support initial ramdisks compressed using XZ"
Lasse Collin3ebe1242011-01-12 17:01:23 -080087 depends on BLK_DEV_INITRD
Andi Kleenec72c662014-12-12 16:58:03 -080088 default y
Lasse Collin3ebe1242011-01-12 17:01:23 -080089 select DECOMPRESS_XZ
90 help
91 Support loading of a XZ encoded initial ramdisk or cpio buffer.
92 If unsure, say N.
93
Albin Tonnerrecacb2462010-01-08 14:42:46 -080094config RD_LZO
Andi Kleenec72c662014-12-12 16:58:03 -080095 bool "Support initial ramdisks compressed using LZO"
96 default y
Albin Tonnerrecacb2462010-01-08 14:42:46 -080097 depends on BLK_DEV_INITRD
98 select DECOMPRESS_LZO
99 help
100 Support loading of a LZO encoded initial ramdisk or cpio buffer
101 If unsure, say N.
102
Kyungsik Leee76e1fd2013-07-08 16:01:46 -0700103config RD_LZ4
Andi Kleenec72c662014-12-12 16:58:03 -0800104 bool "Support initial ramdisks compressed using LZ4"
105 default y
Kyungsik Leee76e1fd2013-07-08 16:01:46 -0700106 depends on BLK_DEV_INITRD
107 select DECOMPRESS_LZ4
108 help
109 Support loading of a LZ4 encoded initial ramdisk or cpio buffer
110 If unsure, say N.
Francisco Blas Izquierdo Riera (klondike)35e669e2016-12-14 15:06:01 -0800111
Francisco Blas Izquierdo Riera (klondike)db2aa7f2016-12-14 15:06:04 -0800112choice
113 prompt "Built-in initramfs compression mode"
114 depends on INITRAMFS_SOURCE!=""
115 optional
116 help
117 This option allows you to decide by which algorithm the builtin
118 initramfs will be compressed. Several compression algorithms are
119 available, which differ in efficiency, compression and
120 decompression speed. Compression speed is only relevant
121 when building a kernel. Decompression speed is relevant at
122 each boot. Also the memory usage during decompression may become
123 relevant on memory constrained systems. This is usually based on the
124 dictionary size of the algorithm with algorithms like XZ and LZMA
125 featuring large dictionary sizes.
126
127 High compression options are mostly useful for users who are
128 low on RAM, since it reduces the memory consumption during
129 boot.
130
131 Keep in mind that your build system needs to provide the appropriate
132 compression tool to compress the generated initram cpio file for
133 embedding.
134
135 If in doubt, select 'None'
136
137config INITRAMFS_COMPRESSION_NONE
138 bool "None"
139 help
140 Do not compress the built-in initramfs at all. This may sound wasteful
141 in space, but, you should be aware that the built-in initramfs will be
142 compressed at a later stage anyways along with the rest of the kernel,
143 on those architectures that support this. However, not compressing the
144 initramfs may lead to slightly higher memory consumption during a
145 short time at boot, while both the cpio image and the unpacked
146 filesystem image will be present in memory simultaneously
147
148config INITRAMFS_COMPRESSION_GZIP
149 bool "Gzip"
150 depends on RD_GZIP
151 help
152 Use the old and well tested gzip compression algorithm. Gzip provides
153 a good balance between compression ratio and decompression speed and
154 has a reasonable compression speed. It is also more likely to be
155 supported by your build system as the gzip tool is present by default
156 on most distros.
157
158config INITRAMFS_COMPRESSION_BZIP2
159 bool "Bzip2"
160 depends on RD_BZIP2
161 help
162 It's compression ratio and speed is intermediate. Decompression speed
163 is slowest among the choices. The initramfs size is about 10% smaller
164 with bzip2, in comparison to gzip. Bzip2 uses a large amount of
165 memory. For modern kernels you will need at least 8MB RAM or more for
166 booting.
167
168 If you choose this, keep in mind that you need to have the bzip2 tool
169 available to be able to compress the initram.
170
171config INITRAMFS_COMPRESSION_LZMA
172 bool "LZMA"
173 depends on RD_LZMA
174 help
175 This algorithm's compression ratio is best but has a large dictionary
176 size which might cause issues in memory constrained systems.
177 Decompression speed is between the other choices. Compression is
178 slowest. The initramfs size is about 33% smaller with LZMA in
179 comparison to gzip.
180
181 If you choose this, keep in mind that you may need to install the xz
182 or lzma tools to be able to compress the initram.
183
184config INITRAMFS_COMPRESSION_XZ
185 bool "XZ"
186 depends on RD_XZ
187 help
188 XZ uses the LZMA2 algorithm and has a large dictionary which may cause
189 problems on memory constrained systems. The initramfs size is about
190 30% smaller with XZ in comparison to gzip. Decompression speed is
191 better than that of bzip2 but worse than gzip and LZO. Compression is
192 slow.
193
194 If you choose this, keep in mind that you may need to install the xz
195 tool to be able to compress the initram.
196
197config INITRAMFS_COMPRESSION_LZO
198 bool "LZO"
199 depends on RD_LZO
200 help
201 It's compression ratio is the second poorest amongst the choices. The
202 kernel size is about 10% bigger than gzip. Despite that, it's
203 decompression speed is the second fastest and it's compression speed
204 is quite fast too.
205
206 If you choose this, keep in mind that you may need to install the lzop
207 tool to be able to compress the initram.
208
209config INITRAMFS_COMPRESSION_LZ4
210 bool "LZ4"
211 depends on RD_LZ4
212 help
213 It's compression ratio is the poorest amongst the choices. The kernel
214 size is about 15% bigger than gzip; however its decompression speed
215 is the fastest.
216
217 If you choose this, keep in mind that most distros don't provide lz4
218 by default which could cause a build failure.
219
220endchoice
221
Francisco Blas Izquierdo Riera (klondike)35e669e2016-12-14 15:06:01 -0800222config INITRAMFS_COMPRESSION
223 string
Francisco Blas Izquierdo Riera (klondike)db2aa7f2016-12-14 15:06:04 -0800224 default "" if INITRAMFS_COMPRESSION_NONE
225 default ".gz" if INITRAMFS_COMPRESSION_GZIP
226 default ".bz2" if INITRAMFS_COMPRESSION_BZIP2
227 default ".lzma" if INITRAMFS_COMPRESSION_LZMA
228 default ".xz" if INITRAMFS_COMPRESSION_XZ
229 default ".lzo" if INITRAMFS_COMPRESSION_LZO
230 default ".lz4" if INITRAMFS_COMPRESSION_LZ4
Francisco Blas Izquierdo Riera (klondike)35e669e2016-12-14 15:06:01 -0800231 default ".gz" if RD_GZIP
232 default ".lz4" if RD_LZ4
233 default ".lzo" if RD_LZO
234 default ".xz" if RD_XZ
235 default ".lzma" if RD_LZMA
236 default ".bz2" if RD_BZIP2
237 default ""