Re: [PATCH] x86: Construct 32 bit boot time page tables in nativeformat.

[H. Peter Anvin]

Rafael J. Wysocki wrote:
> On Monday, 28 of January 2008, Pavel Machek wrote:
> > Hi!
> >
> > > > >  /*
> > > > >   * Swap suspend & friends need this for resume because things like the intel-agp
> > > > >   * driver might have split up a kernel 4MB mapping.
> > > > >   */
> > > > > -char __nosavedata swsusp_pg_dir[PAGE_SIZE]
> > > > > +char swsusp_pg_dir[PAGE_SIZE]
> > > > thanks, applied.
> > Sorry, this is subtle and I've overlooked it before.
> >
> > (I thought you were only changing ifdef).
> >
> > Now you memcpy() over pg_dir when that pgdir is in use during swsusp
> > resume.
>
> It is not.  swsusp hasn't been using swsusp_pg_dir for several months.
> Hence, the patch. :-)
>
> > Granted, you memcpy() with same data that already are there, 
> > but it may still do some funny effects.
> >
> > Hmm, but same argument applies to lower levels of paging in 64-bit and
> > PAE cases, and we still do that memcpy-over-active-pagetables there...
> > :-(.
>
> Actually, no.  We only do that with the kernel code mapping which should be
> safe as long as TLBs are not flushed (and they aren't).

Okay... does that in any way affect using the kernel code mapping 
synchronization code to maintain a set of trampoline pagetables?

	-hpa
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/