booting RHEL6

Tai Pan taipan_yh at
Thu Jul 21 23:34:49 EST 2011

Hello Tony,
Indeed i didn't know that RHEL6 no longer supports POWER5. I guess that explains the second problem. I'll get a POWER6 machine and try it again.

But for the first problem, i'm pretty sure i'll be able to reproduce it again, even on POWER6, as it doesn't really have anything to do with the arch. LOAD_BUFFER_SIZE is just not large enough. I didn't use the RHEL yaboot, i simply compiled it from the tar.gz on the yaboot page. Although RHEL6 uses an older yaboot, 1.3.14, in which LOAD_BUFFER_SIZE is even lower, if i remember correctly.

I'll retry it on POWER6 with the default value and debugging as soon as i can.


From: Tony Breeds <tony at>
To: Tai Pan <taipan_yh at>
Cc: yaboot-users at
Sent: Wednesday, July 13, 2011 3:58 AM
Subject: Re: booting RHEL6

On Mon, Jun 27, 2011 at 07:30:39AM -0700, Tai Pan wrote:
> Hello all,
> I'm having some issues booting rhel6 with yaboot.
> 1) In order to boot the rhel6 kernel i had to increase LOAD_BUFFER_SIZE to
> 0x2600000 in fs_of.c, as the ramdisk is simply too large and it would not get
> all downloaded over tftp.

Which source did you use?

RHEL? Upstream?
If you have time can you rebuild with DEBUG=1 and set the linux,yaboot-debug
environment variable.  This will help us workout if you can even make it work.

> 2) After i got rhel6 to work, i tried the rhel6.1 kernel and this one fails.
> The following is the copy paste of what i see:


> ramdisk loaded at 05700000, size: 32546 Kbytes
> OF stdout device is: /vdevice/vty at 30000000
> Preparing to boot Linux version 2.6.32-131.0.15.el6.ppc64 (mockbuild at (gcc version 4.4.4 20100726 (Red Hat 4.4.4-13) (GCC) ) #1 SMP Tue May 10 15:44:09 EDT 2011
> Max number of cores passed to firmware: 0x0000000000000200
> Calling ibm,client-architecture-support... not implemented
> command line: ks=nfs: br= 
> memory layout at init:
>   memory_limit : 0000000000000000 (16 MB aligned)
>   alloc_bottom : 00000000076d0000
>   alloc_top    : 0000000008000000
>   alloc_top_hi : 0000000077000000
>   rmo_top      : 0000000008000000
>   ram_top      : 0000000077000000
> RTAS allocation failed !

Here's the problem.  Without RTAS The kernel is more or less useless.

Also it looks like  you're trying to install RHEL6 on a power5, you know this
isn't supported by RedHat right?  RHEL is for power6 and newer.

Yours Tony
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