allocating uncachable memory

[Roman Zippel]

Hi,

> Well......there are many devices that perform DMA and must know the
> physical address that is often stored in some kind of device descriptor.
> I have written drivers that convert back and forth to get this
> information.  You would have to keep the address mappings in the
> driver somehow.

Hmm, I only know one driver, where such stuff is needed, but due to lack
of such hardware I never had to deal with this myself.
Anyway, actually in the new page structure there are two fields that are
AFAIK only used by the page cache - mapping and index. With that you can
do a very fast physical to virtual (uncached) translation. (Ok, I take
back that it's impossible :) )

bye, Roman


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