Re: [PATCH v3 1/4] Add support for LZO-compressed kernels

From: Wu Zhangjin
Date: Wed Nov 11 2009 - 09:12:06 EST

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Hi Albin,

Just tested it with the Compressed kernel support of MIPS in Ralf's
linux-queue git repository and with an extra patch for this LZO support
of MIPS on a YeeLoong2F netbook:

http://www.linux-mips.org/archives/linux-mips/2009-10/msg00143.html

It works well.

Thanks & Regards,
Wu Zhangjin

On Wed, 2009-11-11 at 13:27 +0100, Albin Tonnerre wrote:
> This is the first part of the lzo 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 version applies to kernel 2.6.31-rc3
>
> 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
>
> Signed-off-by: Albin Tonnerre <albin.tonnerre@xxxxxxxxxxxxxxxxxx>
> ---
> include/linux/decompress/unlzo.h | 10 ++
> init/Kconfig | 18 +++-
> lib/decompress_unlzo.c | 208 ++++++++++++++++++++++++++++++++++++++
> lib/lzo/lzo1x_decompress.c | 9 +-
> scripts/Makefile.lib | 5 +
> 5 files changed, 243 insertions(+), 7 deletions(-)
> create mode 100644 include/linux/decompress/unlzo.h
> create mode 100644 lib/decompress_unlzo.c
>
> diff --git a/include/linux/decompress/unlzo.h b/include/linux/decompress/unlzo.h
> new file mode 100644
> index 0000000..9872297
> --- /dev/null
> +++ b/include/linux/decompress/unlzo.h
> @@ -0,0 +1,10 @@
> +#ifndef DECOMPRESS_UNLZO_H
> +#define DECOMPRESS_UNLZO_H
> +
> +int unlzo(unsigned char *inbuf, int len,
> + int(*fill)(void*, unsigned int),
> + int(*flush)(void*, unsigned int),
> + unsigned char *output,
> + int *pos,
> + void(*error)(char *x));
> +#endif
> diff --git a/init/Kconfig b/init/Kconfig
> index f515864..eb65318 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -115,10 +115,13 @@ config HAVE_KERNEL_BZIP2
> config HAVE_KERNEL_LZMA
> bool
>
> +config HAVE_KERNEL_LZO
> + bool
> +
> choice
> prompt "Kernel compression mode"
> default KERNEL_GZIP
> - depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA
> + depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_LZO
> help
> The linux kernel is a kind of self-extracting executable.
> Several compression algorithms are available, which differ
> @@ -141,9 +144,8 @@ config KERNEL_GZIP
> bool "Gzip"
> depends on HAVE_KERNEL_GZIP
> help
> - The old and tried gzip compression. Its compression ratio is
> - the poorest among the 3 choices; however its speed (both
> - compression and decompression) is the fastest.
> + The old and tried gzip compression. It provides a good balance
> + between compression ratio and decompression speed.
>
> config KERNEL_BZIP2
> bool "Bzip2"
> @@ -164,6 +166,14 @@ config KERNEL_LZMA
> two. Compression is slowest. The kernel size is about 33%
> smaller with LZMA in comparison to gzip.
>
> +config KERNEL_LZO
> + bool "LZO"
> + depends on HAVE_KERNEL_LZO
> + help
> + Its compression ratio is the poorest among the 4. The kernel
> + size is about about 10% bigger than gzip; however its speed
> + (both compression and decompression) is the fastest.
> +
> endchoice
>
> config SWAP
> diff --git a/lib/decompress_unlzo.c b/lib/decompress_unlzo.c
> new file mode 100644
> index 0000000..2bb736f
> --- /dev/null
> +++ b/lib/decompress_unlzo.c
> @@ -0,0 +1,208 @@
> +/*
> + * LZO decompressor for the Linux kernel. Code borrowed from the lzo
> + * implementation by Markus Franz Xaver Johannes Oberhumer.
> + *
> + * Linux kernel adaptation:
> + * Copyright (C) 2009
> + * Albin Tonnerre, Free Electrons <albin.tonnerre@xxxxxxxxxxxxxxxxxx>
> + *
> + * Original code:
> + * Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer
> + * All Rights Reserved.
> + *
> + * lzop and the LZO library are free software; you can redistribute them
> + * and/or modify them under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; see the file COPYING.
> + * If not, write to the Free Software Foundation, Inc.,
> + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
> + *
> + * Markus F.X.J. Oberhumer
> + * <markus@xxxxxxxxxxxxx>
> + * http://www.oberhumer.com/opensource/lzop/
> + */
> +
> +#ifdef STATIC
> +#include "lzo/lzo1x_decompress.c"
> +#else
> +#include <linux/slab.h>
> +#include <linux/decompress/unlzo.h>
> +#endif
> +
> +#include <linux/types.h>
> +#include <linux/lzo.h>
> +#include <linux/decompress/mm.h>
> +
> +#include <linux/compiler.h>
> +#include <asm/unaligned.h>
> +
> +static const unsigned char lzop_magic[] =
> + { 0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a };
> +
> +#define LZO_BLOCK_SIZE (256*1024l)
> +#define HEADER_HAS_FILTER 0x00000800L
> +
> +STATIC inline int INIT parse_header(u8 *input, u8 *skip)
> +{
> + int l;
> + u8 *parse = input;
> + u8 level = 0;
> + u16 version;
> +
> + /* read magic: 9 first bits */
> + for (l = 0; l < 9; l++) {
> + if (*parse++ != lzop_magic[l])
> + return 0;
> + }
> + /* get version (2bytes), skip library version (2),
> + * 'need to be extracted' version (2) and
> + * method (1) */
> + version = get_unaligned_be16(parse);
> + parse += 7;
> + if (version >= 0x0940)
> + level = *parse++;
> + if (get_unaligned_be32(parse) & HEADER_HAS_FILTER)
> + parse += 8; /* flags + filter info */
> + else
> + parse += 4; /* flags */
> +
> + /* skip mode and mtime_low */
> + parse += 8;
> + if (version >= 0x0940)
> + parse += 4; /* skip mtime_high */
> +
> + l = *parse++;
> + /* don't care about the file name, and skip checksum */
> + parse += l + 4;
> +
> + *skip = parse - input;
> + return 1;
> +}
> +
> +STATIC inline int INIT unlzo(u8 *input, int in_len,
> + int (*fill) (void *, unsigned int),
> + int (*flush) (void *, unsigned int),
> + u8 *output, int *posp,
> + void (*error_fn) (char *x))
> +{
> + u8 skip = 0, r = 0;
> + u32 src_len, dst_len;
> + size_t tmp;
> + u8 *in_buf, *in_buf_save, *out_buf;
> + int obytes_processed = 0;
> +
> + set_error_fn(error_fn);
> +
> + if (output)
> + out_buf = output;
> + else if (!flush) {
> + error("NULL output pointer and no flush function provided");
> + goto exit;
> + } else {
> + out_buf = malloc(LZO_BLOCK_SIZE);
> + if (!out_buf) {
> + error("Could not allocate output buffer");
> + goto exit;
> + }
> + }
> +
> + if (input && fill) {
> + error("Both input pointer and fill function provided, don't know what to do");
> + goto exit_1;
> + } else if (input)
> + in_buf = input;
> + else if (!fill || !posp) {
> + error("NULL input pointer and missing position pointer or fill function");
> + goto exit_1;
> + } else {
> + in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
> + if (!in_buf) {
> + error("Could not allocate input buffer");
> + goto exit_1;
> + }
> + }
> + in_buf_save = in_buf;
> +
> + if (posp)
> + *posp = 0;
> +
> + if (fill)
> + fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE));
> +
> + if (!parse_header(input, &skip)) {
> + error("invalid header");
> + goto exit_2;
> + }
> + in_buf += skip;
> +
> + if (posp)
> + *posp = skip;
> +
> + for (;;) {
> + /* read uncompressed block size */
> + dst_len = get_unaligned_be32(in_buf);
> + in_buf += 4;
> +
> + /* exit if last block */
> + if (dst_len == 0) {
> + if (posp)
> + *posp += 4;
> + break;
> + }
> +
> + if (dst_len > LZO_BLOCK_SIZE) {
> + error("dest len longer than block size");
> + goto exit_2;
> + }
> +
> + /* read compressed block size, and skip block checksum info */
> + src_len = get_unaligned_be32(in_buf);
> + in_buf += 8;
> +
> + if (src_len <= 0 || src_len > dst_len) {
> + error("file corrupted");
> + goto exit_2;
> + }
> +
> + /* decompress */
> + tmp = dst_len;
> + r = lzo1x_decompress_safe((u8 *) in_buf, src_len, out_buf, &tmp);
> +
> + if (r != LZO_E_OK || dst_len != tmp) {
> + error("Compressed data violation");
> + goto exit_2;
> + }
> +
> + obytes_processed += dst_len;
> + if (flush)
> + flush(out_buf, dst_len);
> + if (output)
> + out_buf += dst_len;
> + if (posp)
> + *posp += src_len + 12;
> + if (fill) {
> + in_buf = in_buf_save;
> + fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE));
> + } else
> + in_buf += src_len;
> + }
> +
> +exit_2:
> + if (!input)
> + free(in_buf);
> +exit_1:
> + if (!output)
> + free(out_buf);
> +exit:
> + return obytes_processed;
> +}
> +
> +#define decompress unlzo
> diff --git a/lib/lzo/lzo1x_decompress.c b/lib/lzo/lzo1x_decompress.c
> index 5dc6b29..f2fd098 100644
> --- a/lib/lzo/lzo1x_decompress.c
> +++ b/lib/lzo/lzo1x_decompress.c
> @@ -11,11 +11,13 @@
> * Richard Purdie <rpurdie@xxxxxxxxxxxxxx>
> */
>
> +#ifndef STATIC
> #include <linux/module.h>
> #include <linux/kernel.h>
> -#include <linux/lzo.h>
> -#include <asm/byteorder.h>
> +#endif
> +
> #include <asm/unaligned.h>
> +#include <linux/lzo.h>
> #include "lzodefs.h"
>
> #define HAVE_IP(x, ip_end, ip) ((size_t)(ip_end - ip) < (x))
> @@ -244,9 +246,10 @@ lookbehind_overrun:
> *out_len = op - out;
> return LZO_E_LOOKBEHIND_OVERRUN;
> }
> -
> +#ifndef STATIC
> EXPORT_SYMBOL_GPL(lzo1x_decompress_safe);
>
> MODULE_LICENSE("GPL");
> MODULE_DESCRIPTION("LZO1X Decompressor");
>
> +#endif
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index ffdafb2..39c3483 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -230,3 +230,8 @@ quiet_cmd_lzma = LZMA $@
> cmd_lzma = (cat $(filter-out FORCE,$^) | \
> lzma -9 && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
> (rm -f $@ ; false)
> +
> +quiet_cmd_lzo = LZO $@
> +cmd_lzo = (cat $(filter-out FORCE,$^) | \
> + lzop -9 && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
> + (rm -f $@ ; false)

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Next message: Jiri Kosina: "Re: Using x86 segments against NULL pointer deference exploit"
Previous message: Liam Girdwood: "Re: [PATCH 2/2] regulator/mc13783: various cleanups"
In reply to: Martin Michlmayr: "Re: [PATCH v3 2/4] Add support for LZO-compressed kernels for ARM"
Next in thread: Andrew Morton: "Re: [PATCH v3 1/4] Add support for LZO-compressed kernels"
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