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    SubjectRe: Cache incoherencies (WAS: New resources - pls, explain :-( )
    On Tue, Aug 24, 1999, Philip Blundell <pb@nexus.co.uk> wrote:

    >>Non-cache coherent archs should probably
    >>define a kmalloc flag to allocate non cachable space. (I still don't know
    >>what is the cleanest way to get non-cachable space. ioremap ?).
    >
    >Ioremap won't necessarily work on physical RAM. You should probably define
    >vmalloc_uncached or some such.

    I'm not terribly familiar with Linux VM, and so I'm not completely sure
    how to implement vmalloc_uncached on ARM. I'm wondering if I need to
    re-implement all of vmalloc sub-routines (alloc_area_pmd_uncached,
    alloc_area_pte_uncached) changing the set_pte call to have the
    appropriate attributes ? (BTW. what's the meaning of L_PTE_BUFFERABLE ?).

    or can I just alloc the area and then make pages non-cachable using
    pte_modify afterwards ? In this case I'm not sure how to walk the PTEs...

    Also alloc_are_pte makes several calls to __get_free_page, so I beleive
    there's no way to make sure they are physically contiguous, is there ?
    (note that in our case, on page should be plenty enough)

    Regards,
    Benjamin.

    --
    Perso. e-mail: <mailto:bh40@calva.net>
    Work e-mail: <mailto:benh@mipsys.com>
    BenH. Web : <http://calvaweb.calvacom.fr/bh40/>




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