1 # SPDX-License-Identifier: GPL-2.0 <<
2 # 1 #
3 # Configuration for initramfs 2 # Configuration for initramfs
4 # 3 #
5 4
6 config INITRAMFS_SOURCE 5 config INITRAMFS_SOURCE
7 string "Initramfs source file(s)" 6 string "Initramfs source file(s)"
8 default "" 7 default ""
9 help 8 help
10 This can be either a single cpio arc 9 This can be either a single cpio archive with a .cpio suffix or a
11 space-separated list of directories 10 space-separated list of directories and files for building the
12 initramfs image. A cpio archive sho 11 initramfs image. A cpio archive should contain a filesystem archive
13 to be used as an initramfs image. D 12 to be used as an initramfs image. Directories should contain a
14 filesystem layout to be included in 13 filesystem layout to be included in the initramfs image. Files
15 should contain entries according to 14 should contain entries according to the format described by the
16 "usr/gen_init_cpio" program in the k 15 "usr/gen_init_cpio" program in the kernel tree.
17 16
18 When multiple directories and files 17 When multiple directories and files are specified then the
19 initramfs image will be the aggregat 18 initramfs image will be the aggregate of all of them.
20 19
21 See <file:Documentation/driver-api/e !! 20 See <file:Documentation/early-userspace/README> for more details.
22 21
23 If you are not sure, leave it blank. 22 If you are not sure, leave it blank.
24 23
25 config INITRAMFS_FORCE <<
26 bool "Ignore the initramfs passed by t <<
27 depends on CMDLINE_EXTEND || CMDLINE_F <<
28 help <<
29 This option causes the kernel to ign <<
30 (or initrd image) passed to it by th <<
31 analogous to CMDLINE_FORCE, which is <<
32 and is useful if you cannot or don't <<
33 your bootloader passes to the kernel <<
34 <<
35 config INITRAMFS_ROOT_UID 24 config INITRAMFS_ROOT_UID
36 int "User ID to map to 0 (user root)" 25 int "User ID to map to 0 (user root)"
37 depends on INITRAMFS_SOURCE!="" 26 depends on INITRAMFS_SOURCE!=""
38 default "0" 27 default "0"
39 help 28 help
40 If INITRAMFS_SOURCE points to a dire !! 29 This setting is only meaningful if the INITRAMFS_SOURCE is
41 (-1 = current user) will be owned by !! 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.
42 33
43 If you are not sure, leave it set to 34 If you are not sure, leave it set to "0".
44 35
45 config INITRAMFS_ROOT_GID 36 config INITRAMFS_ROOT_GID
46 int "Group ID to map to 0 (group root) 37 int "Group ID to map to 0 (group root)"
47 depends on INITRAMFS_SOURCE!="" 38 depends on INITRAMFS_SOURCE!=""
48 default "0" 39 default "0"
49 help 40 help
50 If INITRAMFS_SOURCE points to a dire !! 41 This setting is only meaningful if the INITRAMFS_SOURCE is
51 (-1 = current group) will be owned b !! 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.
52 45
53 If you are not sure, leave it set to 46 If you are not sure, leave it set to "0".
54 47
55 config RD_GZIP 48 config RD_GZIP
56 bool "Support initial ramdisk/ramfs co !! 49 bool "Support initial ramdisks compressed using gzip" if EXPERT
57 default y 50 default y
>> 51 depends on BLK_DEV_INITRD
58 select DECOMPRESS_GZIP 52 select DECOMPRESS_GZIP
59 help 53 help
60 Support loading of a gzip encoded in 54 Support loading of a gzip encoded initial ramdisk or cpio buffer.
61 If unsure, say Y. 55 If unsure, say Y.
62 56
63 config RD_BZIP2 57 config RD_BZIP2
64 bool "Support initial ramdisk/ramfs co !! 58 bool "Support initial ramdisks compressed using bzip2" if EXPERT
65 default y !! 59 default !EXPERT
>> 60 depends on BLK_DEV_INITRD
66 select DECOMPRESS_BZIP2 61 select DECOMPRESS_BZIP2
67 help 62 help
68 Support loading of a bzip2 encoded i 63 Support loading of a bzip2 encoded initial ramdisk or cpio buffer
69 If unsure, say N. 64 If unsure, say N.
70 65
71 config RD_LZMA 66 config RD_LZMA
72 bool "Support initial ramdisk/ramfs co !! 67 bool "Support initial ramdisks compressed using LZMA" if EXPERT
73 default y !! 68 default !EXPERT
>> 69 depends on BLK_DEV_INITRD
74 select DECOMPRESS_LZMA 70 select DECOMPRESS_LZMA
75 help 71 help
76 Support loading of a LZMA encoded in 72 Support loading of a LZMA encoded initial ramdisk or cpio buffer
77 If unsure, say N. 73 If unsure, say N.
78 74
79 config RD_XZ 75 config RD_XZ
80 bool "Support initial ramdisk/ramfs co !! 76 bool "Support initial ramdisks compressed using XZ" if EXPERT
81 default y !! 77 default !EXPERT
>> 78 depends on BLK_DEV_INITRD
82 select DECOMPRESS_XZ 79 select DECOMPRESS_XZ
83 help 80 help
84 Support loading of a XZ encoded init 81 Support loading of a XZ encoded initial ramdisk or cpio buffer.
85 If unsure, say N. 82 If unsure, say N.
86 83
87 config RD_LZO 84 config RD_LZO
88 bool "Support initial ramdisk/ramfs co !! 85 bool "Support initial ramdisks compressed using LZO" if EXPERT
89 default y !! 86 default !EXPERT
>> 87 depends on BLK_DEV_INITRD
90 select DECOMPRESS_LZO 88 select DECOMPRESS_LZO
91 help 89 help
92 Support loading of a LZO encoded ini 90 Support loading of a LZO encoded initial ramdisk or cpio buffer
93 If unsure, say N. 91 If unsure, say N.
94 92
95 config RD_LZ4 <<
96 bool "Support initial ramdisk/ramfs co <<
97 default y <<
98 select DECOMPRESS_LZ4 <<
99 help <<
100 Support loading of a LZ4 encoded ini <<
101 If unsure, say N. <<
102 <<
103 config RD_ZSTD <<
104 bool "Support initial ramdisk/ramfs co <<
105 default y <<
106 select DECOMPRESS_ZSTD <<
107 help <<
108 Support loading of a ZSTD encoded in <<
109 If unsure, say N. <<
110 <<
111 choice 93 choice
112 prompt "Built-in initramfs compression !! 94 prompt "Built-in initramfs compression mode" if INITRAMFS_SOURCE!=""
113 depends on INITRAMFS_SOURCE != "" <<
114 help 95 help
115 This option allows you to decide by !! 96 This option decides by which algorithm the builtin initramfs
116 initramfs will be compressed. Sever !! 97 will be compressed. Several compression algorithms are
117 available, which differ in efficienc 98 available, which differ in efficiency, compression and
118 decompression speed. Compression sp 99 decompression speed. Compression speed is only relevant
119 when building a kernel. Decompressi 100 when building a kernel. Decompression speed is relevant at
120 each boot. Also the memory usage dur !! 101 each boot.
121 relevant on memory constrained syste !! 102
122 dictionary size of the algorithm wit !! 103 If you have any problems with bzip2 or LZMA compressed
123 featuring large dictionary sizes. !! 104 initramfs, mail me (Alain Knaff) <alain@knaff.lu>.
124 105
125 High compression options are mostly 106 High compression options are mostly useful for users who are
126 low on RAM, since it reduces the mem 107 low on RAM, since it reduces the memory consumption during
127 boot. 108 boot.
128 109
129 Keep in mind that your build system !! 110 If in doubt, select 'gzip'
130 compression tool to compress the gen <<
131 embedding. <<
132 111
133 If in doubt, select 'None' !! 112 config 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
134 124
135 config INITRAMFS_COMPRESSION_GZIP 125 config INITRAMFS_COMPRESSION_GZIP
136 bool "Gzip" 126 bool "Gzip"
137 depends on RD_GZIP 127 depends on RD_GZIP
138 help 128 help
139 Use the old and well tested gzip com !! 129 The old and tried gzip compression. It provides a good balance
140 a good balance between compression r !! 130 between compression ratio and decompression speed.
141 has a reasonable compression speed. <<
142 supported by your build system as th <<
143 on most distros. <<
144 131
145 config INITRAMFS_COMPRESSION_BZIP2 132 config INITRAMFS_COMPRESSION_BZIP2
146 bool "Bzip2" 133 bool "Bzip2"
147 depends on RD_BZIP2 134 depends on RD_BZIP2
148 help 135 help
149 It's compression ratio and speed is !! 136 Its compression ratio and speed is intermediate.
150 is slowest among the choices. The in !! 137 Decompression speed is slowest among the choices. The initramfs
151 with bzip2, in comparison to gzip. B !! 138 size is about 10% smaller with bzip2, in comparison to gzip.
152 memory. For modern kernels you will !! 139 Bzip2 uses a large amount of memory. For modern kernels you
153 booting. !! 140 will need at least 8MB RAM or more for booting.
154 <<
155 If you choose this, keep in mind tha <<
156 available to be able to compress the <<
157 141
158 config INITRAMFS_COMPRESSION_LZMA 142 config INITRAMFS_COMPRESSION_LZMA
159 bool "LZMA" 143 bool "LZMA"
160 depends on RD_LZMA 144 depends on RD_LZMA
161 help 145 help
162 This algorithm's compression ratio i !! 146 This algorithm's compression ratio is best.
163 size which might cause issues in mem !! 147 Decompression speed is between the other choices.
164 Decompression speed is between the o !! 148 Compression is slowest. The initramfs size is about 33%
165 slowest. The initramfs size is about !! 149 smaller with LZMA in comparison to gzip.
166 comparison to gzip. <<
167 <<
168 If you choose this, keep in mind tha <<
169 or lzma tools to be able to compress <<
170 150
171 config INITRAMFS_COMPRESSION_XZ 151 config INITRAMFS_COMPRESSION_XZ
172 bool "XZ" 152 bool "XZ"
173 depends on RD_XZ 153 depends on RD_XZ
174 help 154 help
175 XZ uses the LZMA2 algorithm and has !! 155 XZ uses the LZMA2 algorithm. The initramfs size is about 30%
176 problems on memory constrained syste !! 156 smaller with XZ in comparison to gzip. Decompression speed
177 30% smaller with XZ in comparison to !! 157 is better than that of bzip2 but worse than gzip and LZO.
178 better than that of bzip2 but worse !! 158 Compression is slow.
179 slow. <<
180 <<
181 If you choose this, keep in mind tha <<
182 tool to be able to compress the init <<
183 159
184 config INITRAMFS_COMPRESSION_LZO 160 config INITRAMFS_COMPRESSION_LZO
185 bool "LZO" 161 bool "LZO"
186 depends on RD_LZO 162 depends on RD_LZO
187 help 163 help
188 Its compression ratio is the second !! 164 Its compression ratio is the poorest among the choices. The kernel
189 kernel size is about 10% bigger than !! 165 size is about 10% bigger than gzip; however its speed
190 decompression speed is the second fa !! 166 (both compression and decompression) is the fastest.
191 is quite fast too. <<
192 <<
193 If you choose this, keep in mind tha <<
194 tool to be able to compress the init <<
195 <<
196 config INITRAMFS_COMPRESSION_LZ4 <<
197 bool "LZ4" <<
198 depends on RD_LZ4 <<
199 help <<
200 It's compression ratio is the poores <<
201 size is about 15% bigger than gzip; <<
202 is the fastest. <<
203 <<
204 If you choose this, keep in mind tha <<
205 by default which could cause a build <<
206 <<
207 config INITRAMFS_COMPRESSION_ZSTD <<
208 bool "ZSTD" <<
209 depends on RD_ZSTD <<
210 help <<
211 ZSTD is a compression algorithm targ <<
212 with fast decompression speed. It wi <<
213 decompress around the same speed as <<
214 <<
215 If you choose this, keep in mind tha <<
216 tool to be able to compress the init <<
217 <<
218 config INITRAMFS_COMPRESSION_NONE <<
219 bool "None" <<
220 help <<
221 Do not compress the built-in initram <<
222 in space, but, you should be aware t <<
223 compressed at a later stage anyways <<
224 on those architectures that support <<
225 initramfs may lead to slightly highe <<
226 short time at boot, while both the c <<
227 filesystem image will be present in <<
228 167
229 endchoice 168 endchoice
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