Messages in this thread | | | Date | Mon, 29 Dec 2008 15:17:31 -0800 | From | Andrew Morton <> | Subject | Re: early fixmap causes kmap breakage |
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On Thu, 18 Dec 2008 22:15:43 +0100 Nick Piggin <npiggin@suse.de> wrote:
> Hi, > > I've debugged a problem where i386+pae systems with more than a few CPUs > blow up at boot in the kmap_atomic code.
ping?
> The problem is that the kmap_atomic pte pages all need to be contiguous > memory because the pte is calculated via the first kmap pte page + an > offset (so as not to have to walk the page tables every time). > > The fixmap setup code crudely allocates contiguous pte pages, which is fine, > but if it finds an already populated pmd entry, then it will not switch it > to a new, contiguous pte page. So the early fixmap introduces a discontig > page table right in the middle of the kmap atomic fixmaps. > > Commenting out the eaarly fixmap setup in head_32.S gets everything working > properly. What would be the best way to fix this? Could we put the early > fixmap page table in initdata, and then have the fixmap setup proper first > clear its corresponding pmd entry?
How come users/testers aren't reporting this?
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