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authorLasse Collin <lasse.collin@tukaani.org>2011-01-12 17:01:24 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 08:03:25 -0800
commit303148045aac34b70db722a54e5ad94a3a6625c6 (patch)
tree9be64b5d44cbef232daf11a89107772cb21647de /Documentation/x86
parent3ebe12439ba7fc62e1d6ecb569b7287771716ca1 (diff)
x86: support XZ-compressed kernel
This integrates the XZ decompression code to the x86 pre-boot code. mkpiggy.c is updated to reserve about 32 KiB more buffer safety margin for kernel decompression. It is done unconditionally for all decompressors to keep the code simpler. The XZ decompressor needs around 30 KiB of heap, so the heap size is increased to 32 KiB on both x86-32 and x86-64. Documentation/x86/boot.txt is updated to list the XZ magic number. With the x86 BCJ filter in XZ, XZ-compressed x86 kernel tends to be a few percent smaller than the equivalent LZMA-compressed kernel. 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 'Documentation/x86')
-rw-r--r--Documentation/x86/boot.txt6
1 files changed, 3 insertions, 3 deletions
diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt
index bdeb81ccb5f..9b7221a86df 100644
--- a/Documentation/x86/boot.txt
+++ b/Documentation/x86/boot.txt
@@ -622,9 +622,9 @@ Protocol: 2.08+
The payload may be compressed. The format of both the compressed and
uncompressed data should be determined using the standard magic
numbers. The currently supported compression formats are gzip
- (magic numbers 1F 8B or 1F 9E), bzip2 (magic number 42 5A) and LZMA
- (magic number 5D 00). The uncompressed payload is currently always ELF
- (magic number 7F 45 4C 46).
+ (magic numbers 1F 8B or 1F 9E), bzip2 (magic number 42 5A), LZMA
+ (magic number 5D 00), and XZ (magic number FD 37). The uncompressed
+ payload is currently always ELF (magic number 7F 45 4C 46).
Field name: payload_length
Type: read