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authorLasse Collin <lasse.collin@tukaani.org>2011-01-12 17:01:23 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 08:03:25 -0800
commit3ebe12439ba7fc62e1d6ecb569b7287771716ca1 (patch)
tree65945a63ad1474489d80c8ca1fb1c1c8091fb7a2 /usr
parent24fa0402a9b6a537e87e38341e78b7da86486846 (diff)
downloadlinux-stericsson-3ebe12439ba7fc62e1d6ecb569b7287771716ca1.tar.gz
decompressors: add boot-time XZ support
This implements the API defined in <linux/decompress/generic.h> which is used for kernel, initramfs, and initrd decompression. This patch together with the first patch is enough for XZ-compressed initramfs and initrd; XZ-compressed kernel will need arch-specific changes. The buffering requirements described in decompress_unxz.c are stricter than with gzip, so the relevant changes should be done to the arch-specific code when adding support for XZ-compressed kernel. Similarly, the heap size in arch-specific pre-boot code may need to be increased (30 KiB is enough). The XZ decompressor needs memmove(), memeq() (memcmp() == 0), and memzero() (memset(ptr, 0, size)), which aren't available in all arch-specific pre-boot environments. I'm including simple versions in decompress_unxz.c, but a cleaner solution would naturally be nicer. Signed-off-by: Lasse Collin <lasse.collin@tukaani.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Alain Knaff <alain@knaff.lu> Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com> Cc: Phillip Lougher <phillip@lougher.demon.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'usr')
-rw-r--r--usr/Kconfig18
-rw-r--r--usr/Makefile5
2 files changed, 22 insertions, 1 deletions
diff --git a/usr/Kconfig b/usr/Kconfig
index c2c7fe2f717d..4780deac5974 100644
--- a/usr/Kconfig
+++ b/usr/Kconfig
@@ -72,6 +72,15 @@ config RD_LZMA
Support loading of a LZMA encoded initial ramdisk or cpio buffer
If unsure, say N.
+config RD_XZ
+ bool "Support initial ramdisks compressed using XZ" if EMBEDDED
+ default !EMBEDDED
+ depends on BLK_DEV_INITRD
+ select DECOMPRESS_XZ
+ help
+ Support loading of a XZ encoded initial ramdisk or cpio buffer.
+ If unsure, say N.
+
config RD_LZO
bool "Support initial ramdisks compressed using LZO" if EMBEDDED
default !EMBEDDED
@@ -139,6 +148,15 @@ config INITRAMFS_COMPRESSION_LZMA
three. Compression is slowest. The initramfs size is about 33%
smaller with LZMA in comparison to gzip.
+config INITRAMFS_COMPRESSION_XZ
+ bool "XZ"
+ depends on RD_XZ
+ help
+ XZ uses the LZMA2 algorithm. The initramfs size is about 30%
+ smaller with XZ in comparison to gzip. Decompression speed
+ is better than that of bzip2 but worse than gzip and LZO.
+ Compression is slow.
+
config INITRAMFS_COMPRESSION_LZO
bool "LZO"
depends on RD_LZO
diff --git a/usr/Makefile b/usr/Makefile
index 6faa444b7087..029ffe6cd0d8 100644
--- a/usr/Makefile
+++ b/usr/Makefile
@@ -15,6 +15,9 @@ suffix_$(CONFIG_INITRAMFS_COMPRESSION_BZIP2) = .bz2
# Lzma
suffix_$(CONFIG_INITRAMFS_COMPRESSION_LZMA) = .lzma
+# XZ
+suffix_$(CONFIG_INITRAMFS_COMPRESSION_XZ) = .xz
+
# Lzo
suffix_$(CONFIG_INITRAMFS_COMPRESSION_LZO) = .lzo
@@ -50,7 +53,7 @@ endif
quiet_cmd_initfs = GEN $@
cmd_initfs = $(initramfs) -o $@ $(ramfs-args) $(ramfs-input)
-targets := initramfs_data.cpio.gz initramfs_data.cpio.bz2 initramfs_data.cpio.lzma initramfs_data.cpio.lzo initramfs_data.cpio
+targets := initramfs_data.cpio.gz initramfs_data.cpio.bz2 initramfs_data.cpio.lzma initramfs_data.cpio.xz initramfs_data.cpio.lzo initramfs_data.cpio
# do not try to update files included in initramfs
$(deps_initramfs): ;