[RFC PATCH v2 2/4] lib: Add support for LZ4-compressed kernel

Kyungsik Lee
2013-02-26T06:24:56Z

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@lge.com>

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@lge.com>
+ *
+ * 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@lge.com>
*
* 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