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-rw-r--r--usr/Kconfig62
-rw-r--r--usr/Makefile18
2 files changed, 68 insertions, 12 deletions
diff --git a/usr/Kconfig b/usr/Kconfig
index a691a8f5898b..43a3a0fe8f29 100644
--- a/usr/Kconfig
+++ b/usr/Kconfig
@@ -71,3 +71,65 @@ config RD_LZMA
71 help 71 help
72 Support loading of a lzma encoded initial ramdisk or cpio buffer 72 Support loading of a lzma encoded initial ramdisk or cpio buffer
73 If unsure, say N. 73 If unsure, say N.
74
75choice
76 prompt "Built-in initramfs compression mode"
77 help
78 This setting is only meaningful if the INITRAMFS_SOURCE is
79 set. It decides by which algorithm the INITRAMFS_SOURCE will
80 be compressed.
81 Several compression algorithms are available, which differ
82 in efficiency, compression and decompression speed.
83 Compression speed is only relevant when building a kernel.
84 Decompression speed is relevant at each boot.
85
86 If you have any problems with bzip2 or lzma compressed
87 initramfs, mail me (Alain Knaff) <alain@knaff.lu>.
88
89 High compression options are mostly useful for users who
90 are low on disk space (embedded systems), but for whom ram
91 size matters less.
92
93 If in doubt, select 'gzip'
94
95config INITRAMFS_COMPRESSION_NONE
96 bool "None"
97 help
98 Do not compress the built-in initramfs at all. This may
99 sound wasteful in space, but, you should be aware that the
100 built-in initramfs will be compressed at a later stage
101 anyways along with the rest of the kernel, on those
102 architectures that support this.
103 However, not compressing the initramfs may lead to slightly
104 higher memory consumption during a short time at boot, while
105 both the cpio image and the unpacked filesystem image will
106 be present in memory simultaneously
107
108config INITRAMFS_COMPRESSION_GZIP
109 bool "Gzip"
110 depends on RD_GZIP
111 help
112 The old and tried gzip compression. Its compression ratio is
113 the poorest among the 3 choices; however its speed (both
114 compression and decompression) is the fastest.
115
116config INITRAMFS_COMPRESSION_BZIP2
117 bool "Bzip2"
118 depends on RD_BZIP2
119 help
120 Its compression ratio and speed is intermediate.
121 Decompression speed is slowest among the three. The initramfs
122 size is about 10% smaller with bzip2, in comparison to gzip.
123 Bzip2 uses a large amount of memory. For modern kernels you
124 will need at least 8MB RAM or more for booting.
125
126config INITRAMFS_COMPRESSION_LZMA
127 bool "LZMA"
128 depends on RD_LZMA
129 help
130 The most recent compression algorithm.
131 Its ratio is best, decompression speed is between the other
132 two. Compression is slowest. The initramfs size is about 33%
133 smaller with LZMA in comparison to gzip.
134
135endchoice
diff --git a/usr/Makefile b/usr/Makefile
index 451cdff7dff9..b84894b3929d 100644
--- a/usr/Makefile
+++ b/usr/Makefile
@@ -5,24 +5,18 @@
5klibcdirs:; 5klibcdirs:;
6PHONY += klibcdirs 6PHONY += klibcdirs
7 7
8# Find out "preferred" ramdisk compressor. Order of preference is
9# 1. bzip2 efficient, and likely to be present
10# 2. gzip former default
11# 3. lzma
12# 4. none
13 8
14# None of the above 9# No compression
15suffix_y = 10suffix_$(CONFIG_INITRAMFS_COMPRESSION_NONE) =
16
17# Lzma, but no gzip nor bzip2
18suffix_$(CONFIG_RD_LZMA) = .lzma
19 11
20# Gzip, but no bzip2 12# Gzip, but no bzip2
21suffix_$(CONFIG_RD_GZIP) = .gz 13suffix_$(CONFIG_INITRAMFS_COMPRESSION_GZIP) = .gz
22 14
23# Bzip2 15# Bzip2
24suffix_$(CONFIG_RD_BZIP2) = .bz2 16suffix_$(CONFIG_INITRAMFS_COMPRESSION_BZIP2) = .bz2
25 17
18# Lzma
19suffix_$(CONFIG_INITRAMFS_COMPRESSION_LZMA) = .lzma
26 20
27# Generate builtin.o based on initramfs_data.o 21# Generate builtin.o based on initramfs_data.o
28obj-$(CONFIG_BLK_DEV_INITRD) := initramfs_data$(suffix_y).o 22obj-$(CONFIG_BLK_DEV_INITRD) := initramfs_data$(suffix_y).o