Re: [PATCH] i386, x86_64 Initial PAT implementation

[Dave Jones]

On Tue, Aug 30, 2005 at 03:45:36PM +0100, Alan Cox wrote:
 > On Llu, 2005-08-29 at 18:20 -0600, Eric W. Biederman wrote:
 > > ways.  Currently this code only allows for an additional flavor
 > > of uncached access to physical memory addresses which should be hard
 > > to abuse, and should raise no additional aliasing problems.  No
 > > attempt has been made to fix theoretical aliasing problems.
 > 
 > Even an uncached/cached alias causes random memory corruption or an MCE
 > on x86 systems. In fact it can occur even for an alias not in theory
 > touched by the CPU if it happens to prefetch into or speculate the
 > address.
 > 
 > Also be sure to read the PII Xeon errata - early PAT has a bug or two.

There are various PAT errata all the way through to Pentium-M iirc.

		Dave

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