lib: add support for LZO-compressed kernels
This patch series adds generic support for creating and extracting LZO-compressed kernel images, as well as support for using such images on the x86 and ARM architectures, and support for creating and using LZO-compressed initrd and initramfs images. Russell King said: : Testing on a Cortex A9 model: : - lzo decompressor is 65% of the time gzip takes to decompress a kernel : - lzo kernel is 9% larger than a gzip kernel : : which I'm happy to say confirms your figures when comparing the two. : : However, when comparing your new gzip code to the old gzip code: : - new is 99% of the size of the old code : - new takes 42% of the time to decompress than the old code : : What this means is that for a proper comparison, the results get even better: : - lzo is 7.5% larger than the old gzip'd kernel image : - lzo takes 28% of the time that the old gzip code took : : So the expense seems definitely worth the effort. The only reason I : can think of ever using gzip would be if you needed the additional : compression (eg, because you have limited flash to store the image.) : : I would argue that the default for ARM should therefore be LZO. This patch: The lzo compressor is worse than gzip at compression, but faster at extraction. Here are some figures for an ARM board I'm working on: Uncompressed size: 3.24Mo gzip 1.61Mo 0.72s lzo 1.75Mo 0.48s So for a compression ratio that is still relatively close to gzip, it's much faster to extract, at least in that case. This part contains: - Makefile routine to support lzo compression - Fixes to the existing lzo compressor so that it can be used in compressed kernels - wrapper around the existing lzo1x_decompress, as it only extracts one block at a time, while we need to extract a whole file here - config dialog for kernel compression [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: cleanup] Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com> Tested-by: Wu Zhangjin <wuzhangjin@gmail.com> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Tested-by: Russell King <rmk@arm.linux.org.uk> Acked-by: Russell King <rmk@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Albin Tonnerre
Linus Torvalds
parent
ac4c2a3bbe
commit
7dd65feb6c
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@ -0,0 +1,10 @@
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#ifndef DECOMPRESS_UNLZO_H
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#define DECOMPRESS_UNLZO_H
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int unlzo(unsigned char *inbuf, int len,
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int(*fill)(void*, unsigned int),
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int(*flush)(void*, unsigned int),
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unsigned char *output,
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int *pos,
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void(*error)(char *x));
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#endif
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18
init/Kconfig
18
init/Kconfig
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@ -115,10 +115,13 @@ config HAVE_KERNEL_BZIP2
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config HAVE_KERNEL_LZMA
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bool
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config HAVE_KERNEL_LZO
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bool
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choice
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prompt "Kernel compression mode"
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default KERNEL_GZIP
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depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA
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depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_LZO
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help
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The linux kernel is a kind of self-extracting executable.
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Several compression algorithms are available, which differ
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@ -141,9 +144,8 @@ config KERNEL_GZIP
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bool "Gzip"
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depends on HAVE_KERNEL_GZIP
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help
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The old and tried gzip compression. Its compression ratio is
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the poorest among the 3 choices; however its speed (both
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compression and decompression) is the fastest.
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The old and tried gzip compression. It provides a good balance
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between compression ratio and decompression speed.
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config KERNEL_BZIP2
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bool "Bzip2"
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@ -164,6 +166,14 @@ config KERNEL_LZMA
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two. Compression is slowest. The kernel size is about 33%
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smaller with LZMA in comparison to gzip.
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config KERNEL_LZO
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bool "LZO"
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depends on HAVE_KERNEL_LZO
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help
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Its compression ratio is the poorest among the 4. The kernel
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size is about about 10% bigger than gzip; however its speed
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(both compression and decompression) is the fastest.
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endchoice
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config SWAP
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@ -0,0 +1,209 @@
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/*
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* LZO decompressor for the Linux kernel. Code borrowed from the lzo
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* implementation by Markus Franz Xaver Johannes Oberhumer.
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*
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* Linux kernel adaptation:
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* Copyright (C) 2009
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* Albin Tonnerre, Free Electrons <albin.tonnerre@free-electrons.com>
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*
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* Original code:
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* Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer
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* All Rights Reserved.
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*
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* lzop and the LZO library are free software; you can redistribute them
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* and/or modify them under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING.
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* If not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Markus F.X.J. Oberhumer
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* <markus@oberhumer.com>
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* http://www.oberhumer.com/opensource/lzop/
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*/
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#ifdef STATIC
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#include "lzo/lzo1x_decompress.c"
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#else
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#include <linux/slab.h>
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#include <linux/decompress/unlzo.h>
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#endif
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#include <linux/types.h>
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#include <linux/lzo.h>
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#include <linux/decompress/mm.h>
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#include <linux/compiler.h>
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#include <asm/unaligned.h>
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static const unsigned char lzop_magic[] = {
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0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a };
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#define LZO_BLOCK_SIZE (256*1024l)
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#define HEADER_HAS_FILTER 0x00000800L
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STATIC inline int INIT parse_header(u8 *input, u8 *skip)
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{
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int l;
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u8 *parse = input;
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u8 level = 0;
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u16 version;
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/* read magic: 9 first bits */
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for (l = 0; l < 9; l++) {
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if (*parse++ != lzop_magic[l])
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return 0;
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}
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/* get version (2bytes), skip library version (2),
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* 'need to be extracted' version (2) and
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* method (1) */
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version = get_unaligned_be16(parse);
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parse += 7;
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if (version >= 0x0940)
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level = *parse++;
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if (get_unaligned_be32(parse) & HEADER_HAS_FILTER)
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parse += 8; /* flags + filter info */
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else
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parse += 4; /* flags */
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/* skip mode and mtime_low */
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parse += 8;
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if (version >= 0x0940)
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parse += 4; /* skip mtime_high */
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l = *parse++;
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/* don't care about the file name, and skip checksum */
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parse += l + 4;
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*skip = parse - input;
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return 1;
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}
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STATIC inline int INIT unlzo(u8 *input, int in_len,
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int (*fill) (void *, unsigned int),
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int (*flush) (void *, unsigned int),
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u8 *output, int *posp,
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void (*error_fn) (char *x))
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{
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u8 skip = 0, r = 0;
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u32 src_len, dst_len;
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size_t tmp;
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u8 *in_buf, *in_buf_save, *out_buf;
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int obytes_processed = 0;
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set_error_fn(error_fn);
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if (output) {
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out_buf = output;
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} else if (!flush) {
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error("NULL output pointer and no flush function provided");
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goto exit;
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} else {
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out_buf = malloc(LZO_BLOCK_SIZE);
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if (!out_buf) {
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error("Could not allocate output buffer");
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goto exit;
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}
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}
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if (input && fill) {
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error("Both input pointer and fill function provided, don't know what to do");
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goto exit_1;
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} else if (input) {
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in_buf = input;
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} else if (!fill || !posp) {
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error("NULL input pointer and missing position pointer or fill function");
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goto exit_1;
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} else {
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in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
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if (!in_buf) {
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error("Could not allocate input buffer");
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goto exit_1;
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}
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}
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in_buf_save = in_buf;
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if (posp)
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*posp = 0;
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if (fill)
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fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE));
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if (!parse_header(input, &skip)) {
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error("invalid header");
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goto exit_2;
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}
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in_buf += skip;
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if (posp)
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*posp = skip;
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for (;;) {
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/* read uncompressed block size */
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dst_len = get_unaligned_be32(in_buf);
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in_buf += 4;
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/* exit if last block */
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if (dst_len == 0) {
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if (posp)
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*posp += 4;
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break;
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}
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if (dst_len > LZO_BLOCK_SIZE) {
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error("dest len longer than block size");
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goto exit_2;
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}
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/* read compressed block size, and skip block checksum info */
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src_len = get_unaligned_be32(in_buf);
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in_buf += 8;
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if (src_len <= 0 || src_len > dst_len) {
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error("file corrupted");
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goto exit_2;
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}
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/* decompress */
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tmp = dst_len;
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r = lzo1x_decompress_safe((u8 *) in_buf, src_len,
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out_buf, &tmp);
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if (r != LZO_E_OK || dst_len != tmp) {
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error("Compressed data violation");
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goto exit_2;
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}
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obytes_processed += dst_len;
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if (flush)
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flush(out_buf, dst_len);
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if (output)
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out_buf += dst_len;
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if (posp)
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*posp += src_len + 12;
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if (fill) {
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in_buf = in_buf_save;
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fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE));
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} else
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in_buf += src_len;
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}
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exit_2:
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if (!input)
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free(in_buf);
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exit_1:
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if (!output)
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free(out_buf);
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exit:
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return obytes_processed;
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}
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#define decompress unlzo
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@ -11,11 +11,13 @@
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* Richard Purdie <rpurdie@openedhand.com>
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*/
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#ifndef STATIC
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/lzo.h>
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#include <asm/byteorder.h>
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#endif
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#include <asm/unaligned.h>
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#include <linux/lzo.h>
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#include "lzodefs.h"
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#define HAVE_IP(x, ip_end, ip) ((size_t)(ip_end - ip) < (x))
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@ -244,9 +246,10 @@ lookbehind_overrun:
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*out_len = op - out;
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return LZO_E_LOOKBEHIND_OVERRUN;
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}
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#ifndef STATIC
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EXPORT_SYMBOL_GPL(lzo1x_decompress_safe);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("LZO1X Decompressor");
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#endif
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@ -235,3 +235,8 @@ quiet_cmd_lzma = LZMA $@
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cmd_lzma = (cat $(filter-out FORCE,$^) | \
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lzma -9 && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
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(rm -f $@ ; false)
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quiet_cmd_lzo = LZO $@
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cmd_lzo = (cat $(filter-out FORCE,$^) | \
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lzop -9 && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
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(rm -f $@ ; false)
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