From: Jesse Barnes <jbarnes@engr.sgi.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: device driver for the SGI system clock, mmtimer
Date: Thu, 16 Sep 2004 10:07:36 -0700
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On Thursday, September 16, 2004 8:52 am, Alan Cox wrote:
> On Iau, 2004-09-16 at 17:09, Jesse Barnes wrote:
> > I think Christoph already looked at that.  And HPET doesn't provide mmap
> > functionality, does it?  I.e. allow a userspace program to dereference
> > the counter register directly?
>
> It can do but that assumes nothing else is mapped into the same page
> that would be harmful or reveal information that should not be revealed
> etc..

And what about the register layout?  mmtimer makes sure that the register is 
on a page by itself before it allows the mmap, and only exports the counter 
register itself.  Can hpet do that?

Jesse
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