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linux-next/init/noinitramfs.c
Jean-Paul Saman c33df4eaaf [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>
2007-02-11 10:51:25 -08:00

53 lines
1.4 KiB
C

/*
* init/noinitramfs.c
*
* Copyright (C) 2006, NXP Semiconductors, All Rights Reserved
* Author: Jean-Paul Saman <jean-paul.saman@nxp.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; version 2 of the License.
*
* 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, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/init.h>
#include <linux/stat.h>
#include <linux/kdev_t.h>
#include <linux/syscalls.h>
/*
* Create a simple rootfs that is similar to the default initramfs
*/
static int __init default_rootfs(void)
{
int err;
err = sys_mkdir("/dev", 0755);
if (err < 0)
goto out;
err = sys_mknod((const char __user *) "/dev/console",
S_IFCHR | S_IRUSR | S_IWUSR,
new_encode_dev(MKDEV(5, 1)));
if (err < 0)
goto out;
err = sys_mkdir("/root", 0700);
if (err < 0)
goto out;
return 0;
out:
printk(KERN_WARNING "Failed to create a rootfs\n");
return err;
}
rootfs_initcall(default_rootfs);