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[RFC PATCH v2 2/4] lib: Add support for LZ4-compressed kernel
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Kyungsik Lee <kyungsik.lee@...>
This patch adds support for extracting LZ4-compressed kernel images,
as well as LZ4-compressed ramdisk images in the kernel boot process. This depends on the patch below decompressor: Add LZ4 decompressor module Signed-off-by: Kyungsik Lee <kyungsik.lee@...> v2: - Clean up code - Use lz4_decompress() for LZ4-compressed kernel during boot-process --- include/linux/decompress/unlz4.h | 10 +++ init/Kconfig | 13 ++- lib/Kconfig | 7 ++ lib/Makefile | 2 + lib/decompress.c | 5 ++ lib/decompress_unlz4.c | 190 +++++++++++++++++++++++++++++++++++++++ lib/lz4/Makefile | 1 + lib/lz4/lz4_decompress.c | 2 +- scripts/Makefile.lib | 5 ++ usr/Kconfig | 9 ++ 10 files changed, 242 insertions(+), 2 deletions(-) create mode 100644 include/linux/decompress/unlz4.h create mode 100644 lib/decompress_unlz4.c create mode 100644 lib/lz4/Makefile diff --git a/include/linux/decompress/unlz4.h b/include/linux/decompress/unlz4.h new file mode 100644 index 0000000..d5b68bf --- /dev/null +++ b/include/linux/decompress/unlz4.h @@ -0,0 +1,10 @@ +#ifndef DECOMPRESS_UNLZ4_H +#define DECOMPRESS_UNLZ4_H + +int unlz4(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 be8b7f5..86dc67c 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -133,10 +133,13 @@ config HAVE_KERNEL_XZ config HAVE_KERNEL_LZO bool +config HAVE_KERNEL_LZ4 + bool + choice prompt "Kernel compression mode" default KERNEL_GZIP - depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO + depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 help The linux kernel is a kind of self-extracting executable. Several compression algorithms are available, which differ @@ -203,6 +206,14 @@ config KERNEL_LZO size is about 10% bigger than gzip; however its speed (both compression and decompression) is the fastest. +config KERNEL_LZ4 + bool "LZ4" + depends on HAVE_KERNEL_LZ4 + help + Its compression ratio is worse than LZO. The size of the kernel + is about 8% bigger than LZO. But the decompression speed is + faster than LZO. + endchoice config DEFAULT_HOSTNAME diff --git a/lib/Kconfig b/lib/Kconfig index 75cdb77..b108047 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -189,6 +189,9 @@ config LZO_COMPRESS config LZO_DECOMPRESS tristate +config LZ4_DECOMPRESS + tristate + source "lib/xz/Kconfig" # @@ -213,6 +216,10 @@ config DECOMPRESS_LZO select LZO_DECOMPRESS tristate +config DECOMPRESS_LZ4 + select LZ4_DECOMPRESS + tristate + # # Generic allocator support is selected if needed # diff --git a/lib/Makefile b/lib/Makefile index 02ed6c0..c2073bf 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -72,6 +72,7 @@ obj-$(CONFIG_REED_SOLOMON) += reed_solomon/ obj-$(CONFIG_BCH) += bch.o obj-$(CONFIG_LZO_COMPRESS) += lzo/ obj-$(CONFIG_LZO_DECOMPRESS) += lzo/ +obj-$(CONFIG_LZ4_DECOMPRESS) += lz4/ obj-$(CONFIG_XZ_DEC) += xz/ obj-$(CONFIG_RAID6_PQ) += raid6/ @@ -80,6 +81,7 @@ lib-$(CONFIG_DECOMPRESS_BZIP2) += decompress_bunzip2.o lib-$(CONFIG_DECOMPRESS_LZMA) += decompress_unlzma.o lib-$(CONFIG_DECOMPRESS_XZ) += decompress_unxz.o lib-$(CONFIG_DECOMPRESS_LZO) += decompress_unlzo.o +lib-$(CONFIG_DECOMPRESS_LZ4) += decompress_unlz4.o obj-$(CONFIG_TEXTSEARCH) += textsearch.o obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o diff --git a/lib/decompress.c b/lib/decompress.c index 31a8042..c70810e 100644 --- a/lib/decompress.c +++ b/lib/decompress.c @@ -11,6 +11,7 @@ #include <linux/decompress/unxz.h> #include <linux/decompress/inflate.h> #include <linux/decompress/unlzo.h> +#include <linux/decompress/unlz4.h> #include <linux/types.h> #include <linux/string.h> @@ -31,6 +32,9 @@ #ifndef CONFIG_DECOMPRESS_LZO # define unlzo NULL #endif +#ifndef CONFIG_DECOMPRESS_LZ4 +# define unlz4 NULL +#endif struct compress_format { unsigned char magic[2]; @@ -45,6 +49,7 @@ static const struct compress_format compressed_formats[] __initdata = { { {0x5d, 0x00}, "lzma", unlzma }, { {0xfd, 0x37}, "xz", unxz }, { {0x89, 0x4c}, "lzo", unlzo }, + { {0x02, 0x21}, "lz4", unlz4 }, { {0, 0}, NULL, NULL } }; diff --git a/lib/decompress_unlz4.c b/lib/decompress_unlz4.c new file mode 100644 index 0000000..84346c4 --- /dev/null +++ b/lib/decompress_unlz4.c @@ -0,0 +1,190 @@ +/* + * Wrapper for decompressing LZ4-compressed kernel, initramfs, and initrd + * + * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@...> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2, + * 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; if not, write to the Free Software + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +#ifdef STATIC +#define PREBOOT +#include "lz4/lz4_decompress.c" +#else +#include <linux/decompress/unlz4.h> +#endif +#include <linux/types.h> +#include <linux/lz4.h> +#include <linux/decompress/mm.h> +#include <linux/compiler.h> + +#include <asm/unaligned.h> + + +#define LZ4_CHUNK_SIZE (8<<20) +#define ARCHIVE_MAGICNUMBER 0x184C2102 + +STATIC inline int INIT unlz4(u8 *input, int in_len, + int (*fill) (void *, unsigned int), + int (*flush) (void *, unsigned int), + u8 *output, int *posp, + void (*error) (char *x)) +{ + int ret = -1; + size_t chunksize = 0; + u8 *inp; + u8 *inp_start; + u8 *outp; + int size = in_len; +#ifdef PREBOOT + size_t out_len = get_unaligned_le32(input + in_len); +#endif + size_t dest_len; + + + if (output) { + outp = output; + } else if (!flush) { + error("NULL output pointer and no flush function provided"); + goto exit_0; + } else { + outp = large_malloc(LZ4_CHUNK_SIZE); + if (!outp) { + error("Could not allocate output buffer"); + goto exit_0; + } + } + + if (input && fill) { + error("Both input pointer and fill function provided,"); + goto exit_1; + } else if (input) { + inp = input; + } else if (!fill) { + error("NULL input pointer and missing fill function"); + goto exit_1; + } else { + inp = large_malloc(LZ4_COMPRESSBOUND(LZ4_CHUNK_SIZE)); + if (!inp) { + error("Could not allocate input buffer"); + goto exit_1; + } + } + inp_start = inp; + + if (posp) + *posp = 0; + + if (fill) + fill(inp, 4); + + chunksize = get_unaligned_le32(inp); + if (chunksize == ARCHIVE_MAGICNUMBER) { + inp += 4; + size -= 4; + } else { + error("invalid header"); + goto exit_2; + } + + if (posp) + *posp += 4; + + for (;;) { + + if (fill) + fill(inp, 4); + + chunksize = get_unaligned_le32(inp); + if (chunksize == ARCHIVE_MAGICNUMBER) { + inp += 4; + size -= 4; + if (posp) + *posp += 4; + continue; + } + inp += 4; + size -= 4; + + if (posp) + *posp += 4; + + if (fill) { + if (chunksize > LZ4_COMPRESSBOUND(LZ4_CHUNK_SIZE)) { + error("chunk length is longer than allocated"); + goto exit_2; + } + fill(inp, chunksize); + } +#ifdef PREBOOT + if (out_len >= LZ4_CHUNK_SIZE) { + dest_len = LZ4_CHUNK_SIZE; + out_len -= dest_len; + } else + dest_len = out_len; + ret = lz4_decompress(inp, &chunksize, outp, dest_len); +#else + dest_len = LZ4_CHUNK_SIZE; + ret = lz4_decompress_unknownoutputsize(inp, chunksize, outp, + &dest_len); +#endif + if (ret < 0) { + error("Decoding failed"); + goto exit_2; + } + + if (flush && flush(outp, dest_len) != dest_len) + goto exit_2; + if (output) + outp += dest_len; + if (posp) + *posp += chunksize; + + size -= chunksize; + + if (size == 0) + break; + else if (size < 0) { + error("data corrupted"); + goto exit_2; + } + + inp += chunksize; + if (fill) + inp = inp_start; + } + + ret = 0; +exit_2: + if (!input) + large_free(inp_start); +exit_1: + if (!output) + large_free(outp); +exit_0: + return ret; +} + +#ifdef PREBOOT +STATIC int INIT decompress(unsigned char *buf, int in_len, + int(*fill)(void*, unsigned int), + int(*flush)(void*, unsigned int), + unsigned char *output, + int *posp, + void(*error)(char *x) + ) +{ + return unlz4(buf, in_len - 4, fill, flush, output, posp, error); +} +#endif diff --git a/lib/lz4/Makefile b/lib/lz4/Makefile new file mode 100644 index 0000000..7f548c6 --- /dev/null +++ b/lib/lz4/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_LZ4_DECOMPRESS) += lz4_decompress.o diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c index 1998d7a..f58eaca 100644 --- a/lib/lz4/lz4_decompress.c +++ b/lib/lz4/lz4_decompress.c @@ -1,7 +1,7 @@ /* * LZ4 Decompressor for Linux kernel * - * Copyright (C) 2013 LG Electronics Co., Ltd. (http://www.lge.com/) + * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@...> * * Based on LZ4 implementation by Yann Collet. * diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index bdf42fd..9293ca1 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -307,6 +307,11 @@ cmd_lzo = (cat $(filter-out FORCE,$^) | \ lzop -9 && $(call size_append, $(filter-out FORCE,$^))) > $@ || \ (rm -f $@ ; false) +quiet_cmd_lz4 = LZ4 $@ +cmd_lz4 = (cat $(filter-out FORCE,$^) | \ + lz4 -c1 stdin stdout && $(call size_append, $(filter-out FORCE,$^))) > $@ || \ + (rm -f $@ ; false) + # U-Boot mkimage # --------------------------------------------------------------------------- diff --git a/usr/Kconfig b/usr/Kconfig index 085872b..642f503 100644 --- a/usr/Kconfig +++ b/usr/Kconfig @@ -90,6 +90,15 @@ config RD_LZO Support loading of a LZO encoded initial ramdisk or cpio buffer If unsure, say N. +config RD_LZ4 + bool "Support initial ramdisks compressed using LZ4" if EXPERT + default !EXPERT + depends on BLK_DEV_INITRD + select DECOMPRESS_LZ4 + help + Support loading of a LZ4 encoded initial ramdisk or cpio buffer + If unsure, say N. + choice prompt "Built-in initramfs compression mode" if INITRAMFS_SOURCE!="" help -- 1.8.1.1 |
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David Sterba <dsterba@...>
On Tue, Feb 26, 2013 at 03:24:28PM +0900, Kyungsik Lee wrote:
+config KERNEL_LZ4Can you please add a sentence what lz4 actually is before you start comparing it with the current competitor(s)? --- /dev/nullPlease use a less cryptic way of representing a value of 8 MB. Also, this is a hardcoded value that must be used on the compressor side. It's an upper limit, so anything below 8MB does not break decompresssion, but this must be somehow checked or saved along in the binary stream. You seem to use the lz4demo.c on the userspace side for compression, but this is not a standard tool nor the output format is well-defined or stabilized. For proper use I would like to see a commandline tool similar to gzip/bzip2/lzop that can be packaged and shipped by distros, and the output format defintion. Yann has some ideas for the format http://fastcompression.blogspot.cz/2012/04/file-container-format-for-lz4.html For kernel, the minimum of meta information is total compressed length, total uncompressed length and chunk size. I don't know if the first two aren't stored elsewhere in the generic kernel image headers, but chunk size must be specified. david |
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Kyungsik Lee <kyungsik.lee@...>
On Tue, Feb 26, 2013 at 03:00:51PM +0100, David Sterba wrote:
On Tue, Feb 26, 2013 at 03:24:28PM +0900, Kyungsik Lee wrote:Yes, I will update it.+config KERNEL_LZ4Can you please add a sentence what lz4 actually is before you start Yes, It will be easy to parse and extract the meta information required--- /dev/nullPlease use a less cryptic way of representing a value of 8 MB. Also, for the kernel decompressor if output format is well-defined and standardized. For proper use I would like to see a commandline tool similar toActually, I would like to use a packaged tool by distros too. lz4demo is what I use for compressing the kernel so far. I name it lz4 in the patch. For kernel, the minimum of meta information is total compressed length,Right, Currently the chunk size used in the kernel decompressor is the same as defined in lz4demo but it should have been provided as meta information. Thanks, Kyungsik |
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