Re: BIOS overwritten during resume (was: Re: Asus L5D resume on battery power)

[Pavel Machek <pavel@suse.cz>]

Hi!

> > > > IIRC kernel code/data is marked as PageReserved(), that's why we need
> > > > to save that :(. Not sure what to do with data e820 marked as
> > > > reserved...
> > > 
> > > Perhaps we need another page flag, like PG_readonly, and mark the pages
> > > reserved by the e820 as PG_reserved | PG_readonly (the same for the areas
> > > that are not returned by e820 at all).  Would that be acceptable?
> > 
> > This flags are little in the short supply, but being able to tell
> > kernel code from memory hole seems like "must have", so yes, that
> > looks ok.
> > 
> > You could get subtle and reuse some other pageflag. I do not think
> > PG_reserved can have PG_locked... So using for example PG_locked for
> > this purpose should be okay.
> 
> The following patch does this.  It is only for x86-64 without
> CONFIG_DISCONTIGMEM, but it has no effect in other cases.

Actually, take a look at Nigel's patch. He simply uses PageNosave
instead of PageLocked -- that is cleaner. He also found a few places
where reserved page becomes un-reserved, and you probably need to fix
those, too.
								Pavel
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