Messages in this thread | | | Date | Fri, 15 Aug 2008 15:30:14 +0100 (BST) | From | Hugh Dickins <> | Subject | Re: [PATCH] x86: fix /proc/meminfo DirectMap |
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On Fri, 15 Aug 2008, Ingo Molnar wrote: > * Hugh Dickins <hugh@veritas.com> wrote: > > > Should we really be using level2_ident_pgt (which needs to avoid NX) > > for the final direct map (which wants to use NX)? But my attempt to > > build up a fresh pagetable there failed miserably to boot! > > hm, exactly what change have you tried? (patch?)
As soon as that kernel failed to boot, I chucked the patch away and erased it from my mind: much better to leave such a change to the people who are intimate with this sequence and can debug it.
It wasn't anything much, the page to use has already been set aside for alloc_low_page, I thought it was just a matter of breaking the association with level2_ident_pgt at the right level then letting phys_pmd_init do its usual setup from scratch.
Maybe it didn't work because I got it slightly wrong, or maybe it it didn't work for more subtle reasons e.g. I was then building up the first 1GB of direct map 2MB by 2MB: if direct map is actually used in there and falls out of TLB, I'd certainly be in trouble.
Hugh
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