[PATCH] disable init/initramfs.c

The file init/initramfs.c is always compiled and linked in the kernel
vmlinux even when BLK_DEV_RAM and BLK_DEV_INITRD are disabled and the
system isn't using any form of an initramfs or initrd.  In this situation
the code is only used to unpack a (static) default initial rootfilesystem.
The current init/initramfs.c code.  usr/initramfs_data.o compiles to a size
of ~15 kbytes.  Disabling BLK_DEV_RAM and BLK_DEV_INTRD shrinks the kernel
code size with ~60 Kbytes.

This patch avoids compiling in the code and data for initramfs support if
CONFIG_BLK_DEV_INITRD is not defined.  Instead of the initramfs code and
data it uses a small routine in init/noinitramfs.c to setup an initial
static default environment for mounting a rootfilesystem later on in the
kernel initialisation process.  The new code is: 164 bytes of size.

The patch is separated in two parts:
1) doesn't compile initramfs code when CONFIG_BLK_DEV_INITRD is not set
2) changing all plaforms vmlinux.lds.S files to not reserve an area of
PAGE_SIZE when CONFIG_BLK_DEV_INITRD is not set.

[deweerdt@free.fr: warning fix]
Signed-off-by: Jean-Paul Saman <jean-paul.saman@nxp.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/init/Kconfig b/init/Kconfig
index a3f83e2c8250..ab6942231045 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -280,8 +280,12 @@ config RELAY
 
 	  If unsure, say N.
 
+if BLK_DEV_INITRD
+
 source "usr/Kconfig"
 
+endif
+
 config CC_OPTIMIZE_FOR_SIZE
 	bool "Optimize for size (Look out for broken compilers!)"
 	default y