Date: Wed, 19 Sep 2001 19:52:23 -0700 From: Julian Elischer <julian@elischer.org> To: Peter Wemm <peter@wemm.org> Cc: John Baldwin <jhb@FreeBSD.org>, hackers@FreeBSD.org Subject: Re: JKH Project: x86: pcb_ext Message-ID: <3BA959E7.43CD9CD6@elischer.org> References: <20010920020136.E7F61380A@overcee.netplex.com.au>
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Peter Wemm wrote:
>
> John Baldwin wrote:
> >
> > On 19-Sep-01 Peter Wemm wrote:
> > > The more I think about it, the right place may be the kse, since that
> > > outlives
> > > the threads and is per-cpu unlike the process.
> > >
> > > Or, we just say "no pcb extensions for kse processes".
> >
> > Each thread would need its own TSS, and to preserve existing semantics, we
> > would have to change the TSS of all threads for each TSS related syscall. In
> > light of that, I vote in favor of "no TSS's for kse processes" since TSS's ar
> e
> > used for very few things anyways. LDT's are another matter and can be moved
> > w/o a problem.
>
> The main two things we seem to use the per-process TSS stuff for are:
> Fine grained IO port permission bitmap
> VM86 mode
> I think we can well do without the complexity of mixing KSE with those two.
<DEVIL'S ADVOCATE>
I could IMAGINE a vm86 version that ran the control/exception
thread on another processor as a different thread. (though who would write it?)
I could also imagine a muli-threaded program doing IO to a device as a userland
driver.
</DEVIL's ADVOCATE>
but of course hey'd need to be writen explicitly for it..
>
> We still would need to sync LDT reloads..
that's more of a worry for me.
Do we still have separate a LDT for threads?
>
> 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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