Re: Cache incoherencies [example code]

Ralf Baechle (ralf@uni-koblenz.de)
Tue, 31 Aug 1999 12:26:38 +0200


On Mon, Aug 30, 1999 at 02:43:19PM +0200, Benjamin Herrenschmidt wrote:

> What happens if I simply try to create an additional mapping for an
> existing page ? Basically, what happens if I use ioremap on the physical
> location of a kmalloc'ed page ?
>
> Of course, I will end up having two virtual mappings to the same page,
> but if I make sure to only actually use the uncachable one, will there be
> a problem ? Would something prevent ioremap from creating a mapping for a
> physical page in the SDRAM range ?

ioremap is not intended to be used for that purpose. It may work for
some systems and fail on others. So you'll have to supply a new function
for that purpose which on some architectures may just be the same as
ioremap.

Ralf

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