lib: add support for LZ4-compressed kernel

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 <kyungsik.lee@lge.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Florian Fainelli <florian@openwrt.org>
Cc: Yann Collet <yann.collet.73@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 16 insertions, 1 deletions

diff --git a/init/Kconfig b/init/Kconfig
index ea1be003275a..54d3fa5ae723 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -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
@@ -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