On Sat, Sep 17, 2011 at 05:08:29PM +0000, Blue Swirl wrote:
> On Wed, Sep 14, 2011 at 8:43 AM, Alexander Graf <ag...@suse.de> wrote:
> > From: David Gibson <da...@gibson.dropbear.id.au>
> >
> > This patch implements support for the CFAR SPR on POWER7 (Come From
> > Address Register), which snapshots the PC value at the time of a branch or
> > an rfid. The latest powerpc-next kernel also catches it and can show it in
> > xmon or in the signal frames.
> >
> > This works well enough to let recent kernels boot (which otherwise oops
> > on the CFAR access). It hasn't been tested enough to be confident that the
> > CFAR values are actually accurate, but one thing at a time.
>
> This looks accurate at least for the cases covered.
>
> A higher performance implementation could be to only update the
> register lazily when the SPR is read, in most other times CFAR would
> be only stored to DisasContext.
Uh, yeah. I think I'll leave that to someone who actually understands
TCG, rather than just bluffing it.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
