Re: [patch] PIII/Katmai & FXSAVE support, disable serial-#, 2.2.2

Charles Cazabon (charlesc-linux@qcc.sk.ca)
Wed, 3 Mar 1999 08:59:14 -0600


Daniel J. Frasnelli <dfrasnel@csee.wvu.edu> wrote:
[original attribution lost, probably was <cat@zip.com.au>]
> >
> > Ie can the cpuid be turned on again by any software? Or is it a one time
> > decision for the life of the cpu or the life of a session (between power-on
> > and power-off)?

> It is my understanding that the psn microcode is only reactivated
> upon system power-up and cannot be activated by a processor reset
> "in-flight" during a Linux session. In other words, you do not have to
> worry about the psn as long as you boot into a kernel with the deactivation
> code.

Intel has said this is the case; however, the German magazine c't has a hacker
on staff who has managed to turn the serial number back on from userland,
using only documented features of the processor.

See the article at http://www.heise.de/ct/english/99/05/news1/

Charles

-- 
----------------------------------------------------
Charles Cazabon           <charlesc-linux@qcc.sk.ca>
Any opinions expressed are just that -- my opinions.
----------------------------------------------------

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