Messages in this thread |  | | | From | Andi Kleen <> | | Subject | Re: [PATCH] i386, x86_64 Initial PAT implementation | | Date | Tue, 30 Aug 2005 16:50:22 +0200 |
| |
On Tuesday 30 August 2005 16:45, 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.
We can always force cpu_has_pat == 0 on these machines. I don't think it is worth it to add any more complicated workarounds for old broken systems.
-Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |