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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