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From: Arnd Bergmann <arnd@arndb.de>
To: linuxppc64-dev@ozlabs.org
Date: Tue, 15 Nov 2005 23:38:53 +0100
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Cc: Christopher Friesen <cfriesen@nortel.com>, linuxppc-embedded@ozlabs.org
Subject: Re: modify the cache-inhibit and guard bits from userspace?
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Am Dienstag 15 November 2005 22:16 schrieb Christopher Friesen:
> What's the most logical way for me to do this? =A0Do I extend mprotect()
> to support additional flags?
>
> Has anyone done this before? =A0I didn't find anything in google.
> Currently the guard bit seems to only be used for ioremap() and in
> __pci_mmap_set_pgprot() if the memory doesn't support write combining.

I have seen an earlier patch that modifies madvise to do this, which seems
a little saner than mprotect, although they can probably both be implemented
in a similar way.

Alternatively, you could write a new file system similar to hugetlbfs and s=
et=20
the cache-inhibit bit in its mmap function.

	Arnd <><