path: root/scripts/xz_wrap.sh
diff options
authorLasse Collin <lasse.collin@tukaani.org>2011-01-12 17:01:22 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 08:03:24 -0800
commit24fa0402a9b6a537e87e38341e78b7da86486846 (patch)
tree06adb32802cf8a3491dff1f4e5cad464c676040a /scripts/xz_wrap.sh
parentfb7fa589fd3ecc212fabd7867a4ecc3b175260c1 (diff)
decompressors: add XZ decompressor module
In userspace, the .lzma format has become mostly a legacy file format that got superseded by the .xz format. Similarly, LZMA Utils was superseded by XZ Utils. These patches add support for XZ decompression into the kernel. Most of the code is as is from XZ Embedded <http://tukaani.org/xz/embedded.html>. It was written for the Linux kernel but is usable in other projects too. Advantages of XZ over the current LZMA code in the kernel: - Nice API that can be used by other kernel modules; it's not limited to kernel, initramfs, and initrd decompression. - Integrity check support (CRC32) - BCJ filters improve compression of executable code on certain architectures. These together with LZMA2 can produce a few percent smaller kernel or Squashfs images than plain LZMA without making the decompression slower. This patch: Add the main decompression code (xz_dec), testing module (xz_dec_test), wrapper script (xz_wrap.sh) for the xz command line tool, and documentation. The xz_dec module is enough to have a usable XZ decompressor e.g. for Squashfs. 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 'scripts/xz_wrap.sh')
1 files changed, 23 insertions, 0 deletions
diff --git a/scripts/xz_wrap.sh b/scripts/xz_wrap.sh
new file mode 100644
index 00000000000..17a5798c29d
--- /dev/null
+++ b/scripts/xz_wrap.sh
@@ -0,0 +1,23 @@
+# This is a wrapper for xz to compress the kernel image using appropriate
+# compression options depending on the architecture.
+# Author: Lasse Collin <lasse.collin@tukaani.org>
+# This file has been put into the public domain.
+# You can do whatever you want with this file.
+case $ARCH in
+ x86|x86_64) BCJ=--x86 ;;
+ powerpc) BCJ=--powerpc ;;
+ ia64) BCJ=--ia64; LZMA2OPTS=pb=4 ;;
+ arm) BCJ=--arm ;;
+ sparc) BCJ=--sparc ;;
+exec xz --check=crc32 $BCJ --lzma2=$LZMA2OPTS,dict=32MiB