Messages in this thread | | | Date | Tue, 01 Jul 2008 13:23:51 -0700 | From | "H. Peter Anvin" <> | Subject | Re: Regression: boot failure on AMD Elan TS-5500 |
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Sean Young wrote: > On Mon, Jun 30, 2008 at 03:42:47PM -0700, H. Peter Anvin wrote: >> Jeremy Fitzhardinge wrote: >>> Maybe it really does require the far jump immediately after setting PE >>> in cr0... >>> >>> Hm, I don't remember this paragraph being in vol 3a, section 8.9.1 >>> before. Is it a recent addition? >>> >>> Random failures can occur if other instructions exist between steps >>> 3 and 4 above. Failures will be readily seen in some situations, >>> such as when instructions that reference memory are inserted between >>> steps 3 and 4 while in system management mode. >>> >> I don't remember that, either. > > Which document are we talking about? >
Intel's Software Developer's Manual, volume 3a.
> I'm afraid it doesn't work. Maybe I can find something in the AMD Elan > documentation. Would a fence make sense?
Not really. In particular, I really don't want to add something that is even remotely likely to break on other platforms, and a fence instruction is relatively recent.
-hpa
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