From: Andi Kleen <ak@suse.de>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Linus Torvalds <torvalds@osdl.org>, Ingo Molnar <mingo@elte.hu>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Arjan van de Ven <arjan@infradead.org>,
Zachary Amsden <zach@vmware.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Michael A Fetterman <Michael.Fetterman@cl.cam.ac.uk>
Subject: Re: Assignment of GDT entries
Date: Thu, 14 Sep 2006 08:00:13 +0200 [thread overview]
Message-ID: <200609140800.13735.ak@suse.de> (raw)
In-Reply-To: <450854F3.20603@goop.org>
On Wednesday 13 September 2006 20:58, Jeremy Fitzhardinge wrote:
> What's the rationale for the current assignment of GDT entries? In
> particular, this section:
AFAIK it was mostly for APM and various BIOS bugs. IIRC Wine had
some special requirements at some point too, but I can't remember them right
now. On x86-64 I use all GDT entries, although there are a few special
ordering restrictions due to the semantics of SYSCALL. I ignored Wine too and
so far nobody has complained, so whatever requirements they have they can't
be that important.
> I'm asking because I'd like to use one of these entries for the PDA
> descriptor, so that it is on the same cache line as the TLS
> descriptors. That way, the entry/exit segment register reloads would
> still only need to touch two GDT cache lines. Would there be a real
> problem in doing this?
The only way to find out would be to do it. It's quite possible that all
the systems with APM BIOS that needed it are long beyond their MTBF.
-Andi
next prev parent reply other threads:[~2006-09-14 7:45 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-09-13 18:58 Assignment of GDT entries Jeremy Fitzhardinge
2006-09-13 19:16 ` Arjan van de Ven
2006-09-13 20:00 ` Alan Cox
2006-09-13 20:02 ` Jeremy Fitzhardinge
2006-09-13 20:20 ` Jeremy Fitzhardinge
2006-09-13 20:59 ` Zachary Amsden
2006-09-13 21:15 ` Jeremy Fitzhardinge
2006-09-13 21:35 ` Alan Cox
2006-09-14 0:25 ` Zachary Amsden
2006-09-14 1:40 ` Stephen Rothwell
2006-09-14 13:03 ` Alan Cox
2006-09-13 19:55 ` linux-os (Dick Johnson)
2006-09-13 20:08 ` Jeremy Fitzhardinge
2006-09-13 20:32 ` linux-os (Dick Johnson)
2006-09-13 21:21 ` Linus Torvalds
2006-09-13 21:47 ` Jeremy Fitzhardinge
2006-09-13 22:05 ` Linus Torvalds
2006-09-13 22:22 ` Jeremy Fitzhardinge
2006-09-14 6:00 ` Andi Kleen [this message]
-- strict thread matches above, loose matches on Subject: below --
2006-09-14 3:23 Albert Cahalan
2006-09-14 6:11 ` Jeremy Fitzhardinge
2006-09-14 4:06 Albert Cahalan
2006-09-14 4:44 ` Eric W. Biederman
2006-09-14 6:19 ` Albert Cahalan
2006-09-14 6:28 ` Zachary Amsden
2006-09-14 7:12 ` Albert Cahalan
2006-09-14 7:24 ` Zachary Amsden
2006-09-14 6:29 ` Jeremy Fitzhardinge
2006-09-15 7:55 Mikael Pettersson
2006-09-15 8:20 ` Jeremy Fitzhardinge
2006-09-15 8:58 ` Mikael Pettersson
2006-09-15 18:27 ` Jeremy Fitzhardinge
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