Date: Fri, 21 Dec 2001 21:51:11 -0800 From: Peter Wemm <peter@wemm.org> To: Julian Elischer <julian@elischer.org> Cc: arch@FreeBSD.ORG Subject: Re: blurk! KSE vs the X86 Message-ID: <20011222055111.C28FA38CC@overcee.netplex.com.au> In-Reply-To: <Pine.BSF.4.21.0112211930050.53471-100000@InterJet.elischer.org>
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Julian Elischer wrote:
>
> Ok so we have this wonderful thing called a TSS
> there is one per CPU by default, but you can ask that your process has it
> own.. that would be one per process.. it has such things as the address
> to load the system stack pointer from when running your process and take a
> trap e.g. syscall.
>
> This is in the PCB extension area. At this time there is only the
> capacity to set an extension into the single thread that would want it,
> and it isn't associated with the process as such via the proc structure,
> just via the PCB extension pointer. So since threads are transient in KSE
> processes when the thread migrates away (almost immediatly in some cases)
> you have no trace of your extension area (hense TSS) so at teh next
> swtch() it'll be gone again..
> the QUICK answer is to say that vm86 and KSE can't be mixed, but
> is that the best solution we can do?
Do not worry about the "best" yet. Lets get a functional baseline
code set that can actually do an upcall and actually do something useful
before worrying about this sort of thing.
ie: until we have something functional in the tree, the policy should
be: KSE is not allowed with {VM86, local LDT, PCB extensions [io port
access], etc.}
The "best" solution will be apparent after we have got the basics
working.
Cheers,
-Peter
--
Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au
"All of this is for nothing if we don't go to the stars" - JMS/B5
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