OFW access from linux

Edward Cherlin echerlin at gmail.com
Thu Sep 17 00:21:09 EDT 2009

On Tue, Sep 15, 2009 at 7:42 AM, Paul Fox <pgf at laptop.org> wrote:
> on the XO, openfirmware stays resident when linux runs, and is
> accessible via an API specified in arch/x86/kernel/ofw.c.  i've
> just pushed a commit to our 2.6.30 kernel branch that adds a
> sysrq hook (SysRq-y) for starting (returning to?) the resident
> OFW command line interface.  when invoked, you can do all the
> usual OFW peeking and poking, and even play pong.  (and, since
> linux is still active, you can royally trash your system if
> you're not careful.)
> there's no SysRq key on the XO keyboard, so you'll need to use a
> break on the serial console to invoke it, or, usually easier:
> "echo y > /proc/sysrq-trigger".  use "resume" from OFW to let
> linux run again.

Added to




http://wiki.sugarlabs.org/go/The undiscoverable

Thanks again.

> OFW itself prevents invocation on secure machines, so this
> only works when unlocked.

> paul
> =---------------------
>  paul fox, pgf at laptop.org
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Edward Mokurai (默雷/धर्ममेघशब्दगर्ज/دھرممیگھشبدگر ج) Cherlin
Silent Thunder is my name, and Children are my nation.
The Cosmos is my dwelling place, the Truth my destination.

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