init/Kconfig: add an option for uncompressed kernel

Add "None" as the kernel compression mode.

This option is useful for debugging the kernel in slow simulation
environments, where decompressing and moving the kernel is awfully slow.

Uncompressed kernel implementation might allow early boot code to skip the
decompressor and jump right at uncompressed kernel image entry point.

Platforms implementing that should define HAVE_KERNEL_UNCOMPRESSED.

Reviewed-by: Heiko Carstens <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>
Signed-off-by: Martin Schwidefsky <[email protected]>

init/Kconfig

@@ -125,10 +125,13 @@ config HAVE_KERNEL_LZO
 config HAVE_KERNEL_LZ4
 	bool
 
+config HAVE_KERNEL_UNCOMPRESSED
+	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 || HAVE_KERNEL_LZ4
+	depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 || HAVE_KERNEL_UNCOMPRESSED
 	help
 	  The linux kernel is a kind of self-extracting executable.
 	  Several compression algorithms are available, which differ
@@ -207,6 +210,16 @@ config KERNEL_LZ4
 	  is about 8% bigger than LZO. But the decompression speed is
 	  faster than LZO.
 
+config KERNEL_UNCOMPRESSED
+	bool "None"
+	depends on HAVE_KERNEL_UNCOMPRESSED
+	help
+	  Produce uncompressed kernel image. This option is usually not what
+	  you want. It is useful for debugging the kernel in slow simulation
+	  environments, where decompressing and moving the kernel is awfully
+	  slow. This option allows early boot code to skip the decompressor
+	  and jump right at uncompressed kernel image.
+
 endchoice
 
 config DEFAULT_HOSTNAME