Re: Init not working in 64-bit kernel

[Ralf Baechle <ralf@linux-mips.org>]

On Fri, Mar 17, 2006 at 03:36:50PM +0530, Vadivelan@soc-soft.com wrote:

> 	I'm porting a 64-bit linux kernel provided for a mips4
> architecture to a mips3 target board. The existing NFS root file system
> has been compiled for a 64-bit mips4 architecture.
> If I mount this file system, the init does not run.
> After mounting the filesystem, I get the following messages and the
> kernel hangs.
> 
> -------------------------------------------------
> Looking up port of RPC 100003/2 on 192.168.5.93
> Looking up port of RPC 100005/1 on 192.168.5.93
> VFS: Mounted root (nfs filesystem).
> Freeing unused kernel memory: 132k freed

That's a rather generic kind of death uppon entry of userspace sympthom,
so I cannot really give alot of advice other than below:

> I also tried to mount a 32-bit working NFS root filesystem.
> Still I get the same problem. I thought 32-bit binaries will execute
> fine in 64-bit kernel.

They do - but you need to enable 32-bit compatibility:

CONFIG_MIPS32_COMPAT=y
CONFIG_MIPS32_O32=y

And if you have an N32 root filesystem (unlikely) you also have to set
CONFIG_MIPS32_N32=y.

> Do I have to recompile the binutils and glibc for my target file system?

No.  The entire software should just work.

> Kindly ignore the confidentiality notice attached at the end of the
> mail. It is an automatically generated one and I cannot remove it.I'm
> extremely sorry for the inconvenience.

We're fabulous at ignoring things ;-)

  Ralf