[BULK] Re: [LinuxBIOS] Re: ROMCC bug

Eric W. Biederman ebiederman at lnxi.com
Tue Jun 21 00:28:43 CEST 2005

yhlu <yinghailu at gmail.com> writes:

> So we must make cache_as_ram work on other 86 platform besides amd cpu...

It is a good idea and for new cpus it is probably an option.
For people in the embedded space we still need romcc.

> Is there any intel public doc about using cache_as_ram?

I have not seen any yet which is a puzzle.  For the first round
of Intel cpus that supported it you had to load a microcode update,
before it would work.  I have yet to see if AMD's flavor will work
on k8 revisions B3, C0, CG, Ex.  I expect it will but I have been
burnt too many times.

> I have tried amd cache_as_ram in intel platform, it seem if access
> some position several times, the contents of that address will become
> to 0xff....

Exactly the problem. If you aren't using a supported flavor of cache
as ram it fails more often and in less predictable ways than romcc.
That is why I avoid it unless the manufacturer supports it.  And that
is why we cannot decompress and run code out of the cache. 


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