From: Derek Fawcus <dfawcus@cisco.com>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] pathetic
Date: Thu, 26 Feb 2004 01:15:39 +0000 [thread overview]
Message-ID: <20040226011539.N7383@edinburgh.cisco.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0402250900080.9147-100000@maxroach.lanl.gov>; from rminnich@lanl.gov on Wed, Feb 25, 2004 at 09:02:45AM -0700
On Wed, Feb 25, 2004 at 09:02:45AM -0700, ron minnich wrote:
> On Wed, 25 Feb 2004, Derek Fawcus wrote:
>
> well ... on e.g. linux, the segment descriptors are used. Paging on x86 is
Well the descriptors have to be there, but they're ususally set for 1:1
mapping (phys == linear). It used to be that linux used the segments
for proc protection, then just for the 3G limit, now I believe they
are set 1:1 and everything done with pages.
> in addition to segments. segment are earlier in address translation path
> than pages, and they are still there when paging is turned on. It's quite
> weird.
err - later.
Virt => Linear (via paging h/w). Then Linear => Phys (via segment h/w).
> I don't see an NX bit in my pentium manual.
That's what AMD are supposed to have added. That's what the whole hoohaw is
about, they've added a bit somewhere (I'd guess a spare bit from the page
descriptor) such that a page can be non execute.
DF
next prev parent reply other threads:[~2004-02-26 1:15 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-02-25 15:26 ron minnich
2004-02-25 15:41 ` Derek Fawcus
2004-02-25 16:02 ` ron minnich
2004-02-26 1:15 ` Derek Fawcus [this message]
2004-02-26 3:45 ` ron minnich
2004-02-26 4:12 ` Derek Fawcus
2004-02-26 6:48 ` boyd, rounin
2004-02-26 6:41 ` boyd, rounin
2004-02-25 16:26 ` Aharon Robbins
2004-02-26 6:02 ` boyd, rounin
2004-02-26 10:41 ` Douglas A. Gwyn
2004-02-26 11:32 ` Charles Forsyth
2004-02-26 11:33 ` Geoff Collyer
2004-02-26 12:39 ` Dave Lukes
2004-02-26 12:11 ` boyd, rounin
2004-02-26 13:42 ` dbailey27
2004-02-26 14:36 ` ron minnich
2004-02-26 14:41 ` David Presotto
2004-02-26 14:40 ` dbailey27
2004-02-26 14:47 ` ron minnich
2004-02-26 14:44 ` dbailey27
2004-02-26 15:28 ` ron minnich
2004-02-26 15:38 ` George Michaelson
2004-02-26 16:16 ` ron minnich
2004-02-26 17:32 ` [9fans] SPF+SMTP C H Forsyth
2004-03-01 10:34 ` [9fans] pathetic Vin McLellan
2004-02-26 15:38 ` dbailey27
2004-02-26 14:58 ` andrey mirtchovski
2004-02-26 15:53 ` dbailey27
2004-02-27 9:01 ` boyd, rounin
2004-02-27 10:52 ` Geoff Collyer
2004-02-27 13:07 ` David Presotto
2004-02-27 20:26 ` Lyndon Nerenberg
2004-02-27 22:22 ` Tristan Seligmann
2004-02-27 23:36 ` Geoff Collyer
2004-02-27 13:42 ` Dave Lukes
2004-02-27 15:42 ` a
2004-02-27 17:45 ` 9nut
2004-02-27 23:10 ` boyd, rounin
2004-02-29 21:11 ` boyd, rounin
2004-02-26 15:16 ` C H Forsyth
2004-02-26 15:37 ` Dave Lukes
2004-02-26 17:55 ` jmk
2004-02-26 19:23 ` Richard Miller
2004-02-26 19:35 ` jmk
2004-02-26 19:50 ` Richard Miller
2004-02-27 11:04 ` Dan Moniz
2004-02-26 20:46 ` boyd, rounin
2004-02-26 15:37 ` Derek Fawcus
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