[Buildroot] Changing from NFS root filesystem to embedded within kernel

[Buildroot] Changing from NFS root filesystem to embedded within kernel

[Guillaume Dargaud]

Hello all,
It's probably a simple question, but I'm a bit confused by what I found 
searching this question.
I have a buildroot system which currently boots remotely via DHCP+NFS.
The following is both in the dts file and as the kernel parameter line:
console=ttyUL0,115200 rw root=/dev/nfs ip=bootp

Now I would like to package the kernel with the filesystem embedded in it. 
That's what initramfs is for, right ?

In buildroot, I generated a CPIO filesystem, and in the kernel compile options 
I told it to use that file as an initramfs.

Now all I need is to change the kernel parameter line, right ? What's the 
syntax ?
-- 
Guillaume Dargaud
http://www.gdargaud.net/Antarctica/

[Buildroot] Changing from NFS root filesystem to embedded within kernel

[Baruch Siach]

Hi Guillaume,

On Wed, Feb 23, 2011 at 06:03:40PM +0100, Guillaume Dargaud wrote:
> It's probably a simple question, but I'm a bit confused by what I found 
> searching this question.
> I have a buildroot system which currently boots remotely via DHCP+NFS.
> The following is both in the dts file and as the kernel parameter line:
> console=ttyUL0,115200 rw root=/dev/nfs ip=bootp
> 
> Now I would like to package the kernel with the filesystem embedded in it. 
> That's what initramfs is for, right ?
> 
> In buildroot, I generated a CPIO filesystem, and in the kernel compile options 
> I told it to use that file as an initramfs.
> 
> Now all I need is to change the kernel parameter line, right ? What's the 
> syntax ?

No. If you include initramfs in your kernel, the /init script runs 
automatically, regardless of the kernel command line. In this script you can 
examine the kernel command line (available in /proc/cmdline), and mount the 
right filesystem. See the Documentation/filesystems/ramfs-rootfs-initramfs.txt 
file under "What is initramfs?".

baruch

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