initramfs: Add skip_initramfs command line option

Add a skip_initramfs option to allow choosing whether to boot using
the initramfs or not at runtime.

Change-Id: If30428fa748c1d4d3d7b9d97c1f781de5e4558c3
Signed-off-by: Rom Lemarchand <romlem@google.com>
Git-commit: 6f36227aa43c9e4b17a2dcda6a38e79d1b00d1b5
Git-repo: https://android.googlesource.com/kernel/common.git
Signed-off-by: Kaushal Kumar <kaushalk@codeaurora.org>
This commit is contained in:
Rom Lemarchand 2015-07-06 16:50:33 -07:00 committed by Kaushal Kumar
parent 107cd6cb6c
commit 12bf38fe2c
4 changed files with 58 additions and 5 deletions

32
include/linux/initramfs.h Normal file
View File

@ -0,0 +1,32 @@
/*
* include/linux/initramfs.h
*
* Copyright (C) 2015, Google
* Rom Lemarchand <romlem@android.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
*/
#ifndef _LINUX_INITRAMFS_H
#define _LINUX_INITRAMFS_H
#include <linux/kconfig.h>
#if IS_BUILTIN(CONFIG_BLK_DEV_INITRD)
int __init default_rootfs(void);
#endif
#endif /* _LINUX_INITRAMFS_H */

View File

@ -3,11 +3,8 @@
#
obj-y := main.o version.o mounts.o
ifneq ($(CONFIG_BLK_DEV_INITRD),y)
obj-y += noinitramfs.o
else
obj-$(CONFIG_BLK_DEV_INITRD) += initramfs.o
endif
obj-$(CONFIG_GENERIC_CALIBRATE_DELAY) += calibrate.o
ifneq ($(CONFIG_ARCH_INIT_TASK),y)

View File

@ -18,6 +18,7 @@
#include <linux/dirent.h>
#include <linux/syscalls.h>
#include <linux/utime.h>
#include <linux/initramfs.h>
static __initdata char *message;
static void __init error(char *x)
@ -579,9 +580,25 @@ static void __init clean_rootfs(void)
}
#endif
static int __initdata do_skip_initramfs;
static int __init skip_initramfs_param(char *str)
{
if (*str)
return 0;
do_skip_initramfs = 1;
return 1;
}
__setup("skip_initramfs", skip_initramfs_param);
static int __init populate_rootfs(void)
{
char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
char *err;
if (do_skip_initramfs)
return default_rootfs();
err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
if (err)
panic(err); /* Failed to decompress INTERNAL initramfs */
if (initrd_start) {

View File

@ -21,11 +21,16 @@
#include <linux/stat.h>
#include <linux/kdev_t.h>
#include <linux/syscalls.h>
#include <linux/kconfig.h>
#include <linux/initramfs.h>
/*
* Create a simple rootfs that is similar to the default initramfs
*/
static int __init default_rootfs(void)
#if !IS_BUILTIN(CONFIG_BLK_DEV_INITRD)
static
#endif
int __init default_rootfs(void)
{
int err;
@ -49,4 +54,6 @@ out:
printk(KERN_WARNING "Failed to create a rootfs\n");
return err;
}
#if !IS_BUILTIN(CONFIG_BLK_DEV_INITRD)
rootfs_initcall(default_rootfs);
#endif