From 3ebe12439ba7fc62e1d6ecb569b7287771716ca1 Mon Sep 17 00:00:00 2001 From: Lasse Collin Date: Wed, 12 Jan 2011 17:01:23 -0800 Subject: decompressors: add boot-time XZ support This implements the API defined in 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 Cc: "H. Peter Anvin" Cc: Alain Knaff Cc: Albin Tonnerre Cc: Phillip Lougher Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- usr/Kconfig | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'usr/Kconfig') 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 -- cgit v1.2.3