[PATCH] UBUNTU: SAUCE: dove: avoid page table overwrite when resuming from hibernation

[Rafael J. Wysocki]

On Friday 28 May 2010, Eric Miao wrote:
> On Fri, May 28, 2010 at 12:20 PM, Nigel Cunningham
> <ncunningham at crca.org.au> wrote:
> > Hi Eric.
> >
> > On 28/05/10 14:13, Eric Miao wrote:
> >>
> >> Forget about upstream at this moment, since the hibernation support for
> >> Dove
> >> is quite specific now, and even it's going to be supported in
> >> upstream, it will have
> >> to made generic so other SoC can benefit. This patch isn't ready for
> >> upstream yet.
> >
> > I understand that the arch isn't in upstream. I think that the issue is
> > though. If I'm right, you're seeing this issue not because of a problem in
> > your arch specific code, but because of a problem in vanilla that's more
> > easily triggered on your arch. That's why I wanted to bring it to Rafael's
> > attention.
> >
> 
> Ah right. I seem to remember the x86 has a workaround to avoid the issue of
> page table being overwritten by copying back-n-forth.

Yes, it does.  We create temporary page tables before the copying on x86.

> I'm not sure if there are any specific way of doing so. In ARM case,
> temporarily using the init page table seems to be a workable solution,
> though.

That used to work on x86 too, but we had to use a different approach because
of some low-level changes of the arch memory management.

Rafael