From: Jamie Lokier <jamie@shareable.org>
To: Pavel Machek <pavel@suse.cz>
Cc: Mikael Pettersson <mikpe@csd.uu.se>,
jim.houston@comcast.net, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Pentium Pro - sysenter - doublefault
Date: Mon, 8 Sep 2003 15:05:43 +0100 [thread overview]
Message-ID: <20030908140543.GA26269@mail.jlokier.co.uk> (raw)
In-Reply-To: <20030903125019.GN1358@openzaurus.ucw.cz>
Pavel Machek wrote:
> > "SEP is unsupported". It's interesting that Pentium Pro erratum #82
> > is "SYSENTER/SYSEXIT instructions can implicitly load 'null segment
> > selector' to SS and CS registers", implying that SYSENTER does
> > _something_ useful on PPros.
>
> Well, with CS==0 machine is not going to survive too long.
> If it only happens sometimes you might catch the double fault
> and fixup, but....
The erratum only applies when you load CS==0 _deliberately_, by setting
the MSR to that.
I'm wondering what happens when you don't do silly things - what is
the undocumented behaviour of SYSENTER/SYSEXIT on those chips?
I vaguely recall reading details about the behaviour change made by
Intel, around the time it was done, but I can't see to find it
anywhere.
-- Jamie
next prev parent reply other threads:[~2003-09-08 14:06 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-21 20:41 [PATCH] Pentium Pro - sysenter - doublefault Jim Houston
2003-08-21 21:32 ` Mikael Pettersson
2003-08-22 2:18 ` [PATCH2] " Jim Houston
2003-08-25 5:56 ` [PATCH] " Jamie Lokier
2003-08-25 6:09 ` Jamie Lokier
2003-09-03 12:50 ` Pavel Machek
2003-09-08 14:05 ` Jamie Lokier [this message]
2003-08-25 4:05 ` Jamie Lokier
2003-08-25 4:14 ` Jakob Oestergaard
2003-08-25 5:50 ` Jamie Lokier
2003-08-25 6:29 ` Jamie Lokier
2003-08-25 7:49 ` Jakob Oestergaard
2003-08-25 18:15 ` Jim Houston
2003-08-26 12:26 ` Richard Curnow
2003-08-27 14:01 ` Jamie Lokier
2003-08-27 14:23 ` Richard Curnow
2003-08-27 14:25 ` dl-ipaddr
2003-08-27 15:15 ` Stan Bubrouski
2003-08-27 16:02 ` Pasi Savolainen
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