Skip to content

Commit

Permalink
lib: add support for LZ4-compressed kernel
Browse files Browse the repository at this point in the history
Add support for extracting LZ4-compressed kernel images, as well as
LZ4-compressed ramdisk images in the kernel boot process.

Signed-off-by: Kyungsik Lee <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Russell King <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Florian Fainelli <[email protected]>
Cc: Yann Collet <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
  • Loading branch information
Kyungsik Lee authored and torvalds committed Jul 9, 2013
1 parent cffb78b commit e76e1fd
Show file tree
Hide file tree
Showing 10 changed files with 243 additions and 2 deletions.
10 changes: 10 additions & 0 deletions include/linux/decompress/unlz4.h
Original file line number Diff line number Diff line change
@@ -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
17 changes: 16 additions & 1 deletion init/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -112,10 +112,13 @@ 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
Expand Down Expand Up @@ -182,6 +185,18 @@ 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
LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding.
A preliminary version of LZ4 de/compression tool is available at
<https://code.google.com/p/lz4/>.

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
Expand Down
7 changes: 7 additions & 0 deletions lib/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -194,6 +194,9 @@ config LZO_COMPRESS
config LZO_DECOMPRESS
tristate

config LZ4_DECOMPRESS
tristate

source "lib/xz/Kconfig"

#
Expand All @@ -218,6 +221,10 @@ config DECOMPRESS_LZO
select LZO_DECOMPRESS
tristate

config DECOMPRESS_LZ4
select LZ4_DECOMPRESS
tristate

#
# Generic allocator support is selected if needed
#
Expand Down
2 changes: 2 additions & 0 deletions lib/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -75,6 +75,7 @@ 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/

Expand All @@ -83,6 +84,7 @@ 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
Expand Down
5 changes: 5 additions & 0 deletions lib/decompress.c
Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand All @@ -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];
Expand All @@ -45,6 +49,7 @@ static const struct compress_format compressed_formats[] __initconst = {
{ {0x5d, 0x00}, "lzma", unlzma },
{ {0xfd, 0x37}, "xz", unxz },
{ {0x89, 0x4c}, "lzo", unlzo },
{ {0x02, 0x21}, "lz4", unlz4 },
{ {0, 0}, NULL, NULL }
};

Expand Down
187 changes: 187 additions & 0 deletions lib/decompress_unlz4.c
Original file line number Diff line number Diff line change
@@ -0,0 +1,187 @@
/*
* Wrapper for decompressing LZ4-compressed kernel, initramfs, and initrd
*
* Copyright (C) 2013, LG Electronics, Kyungsik Lee <[email protected]>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/

#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>

/*
* Note: Uncompressed chunk size is used in the compressor side
* (userspace side for compression).
* It is hardcoded because there is not proper way to extract it
* from the binary stream which is generated by the preliminary
* version of LZ4 tool so far.
*/
#define LZ4_DEFAULT_UNCOMPRESSED_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;
size_t uncomp_chunksize = LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE;
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(uncomp_chunksize);
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(uncomp_chunksize));
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(uncomp_chunksize)) {
error("chunk length is longer than allocated");
goto exit_2;
}
fill(inp, chunksize);
}
#ifdef PREBOOT
if (out_len >= uncomp_chunksize) {
dest_len = uncomp_chunksize;
out_len -= dest_len;
} else
dest_len = out_len;
ret = lz4_decompress(inp, &chunksize, outp, dest_len);
#else
dest_len = uncomp_chunksize;
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
1 change: 1 addition & 0 deletions lib/lz4/Makefile
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
obj-$(CONFIG_LZ4_DECOMPRESS) += lz4_decompress.o
2 changes: 1 addition & 1 deletion lib/lz4/lz4_decompress.c
Original file line number Diff line number Diff line change
@@ -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@lge.com>
*
* Based on LZ4 implementation by Yann Collet.
*
Expand Down
5 changes: 5 additions & 0 deletions scripts/Makefile.lib
Original file line number Diff line number Diff line change
Expand Up @@ -311,6 +311,11 @@ cmd_lzo = (cat $(filter-out FORCE,$^) | \
lzop -9 && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
(rm -f $@ ; false)

quiet_cmd_lz4 = LZ4 $@
cmd_lz4 = (cat $(filter-out FORCE,$^) | \
lz4c -l -c1 stdin stdout && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
(rm -f $@ ; false)

# U-Boot mkimage
# ---------------------------------------------------------------------------

Expand Down
9 changes: 9 additions & 0 deletions usr/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down

0 comments on commit e76e1fd

Please sign in to comment.