From: "Petr Vandrovec" <VANDROVE@vc.cvut.cz>
To: Dan Hollis <goemon@anime.net>
Cc: <linux-kernel@vger.kernel.org>, torvalds@transmeta.com
Subject: Re: Re[2]: [PATCH] Athlon bug stomper. Pls apply.
Date: Wed, 19 Sep 2001 20:57:59 MET-1 [thread overview]
Message-ID: <3ED700D6987@vcnet.vc.cvut.cz> (raw)
On 19 Sep 01 at 11:43, Dan Hollis wrote:
> On Wed, 19 Sep 2001, Linus Torvalds wrote:
> > It is _probably_ an undocumented performance thing, and clearing that
> > bit may slow something down. But it might also change some behaviour,
> > and knowing _what_ the behaviour is might be very useful for figuring
> > out what it is that triggers the problem.
>
> AFAIK noone has even tested it yet to see what it does to performance! Eg
> it might slow down memory access so that athlon-optimized memcopy is now
> slower than non-athlon-optimized memcopy. And if it turns out to be the
> case, we might as well just use the non-athlon-optimized memcopy instead
> of twiddling undocumented northbridge bits...
No, we cannot. On boxes which do not work with athlon optimized kernels
any user can execute athlon's fast_page_copy from userspace, causing
corruption on completely unrelated pages, eventually leading to
kernel crash... So you cannot allow untrusted users on such machine.
Best regards,
Petr Vandrovec
vandrove@vc.cvut.cz
next reply other threads:[~2001-09-19 18:58 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-09-19 20:57 Petr Vandrovec [this message]
-- strict thread matches above, loose matches on Subject: below --
2001-09-19 16:59 Re[2]: [PATCH] Athlon bug stomper. Pls apply Petr Vandrovec
2001-09-19 15:03 ` Liakakis Kostas
2001-09-19 15:14 ` Gergely Tamas
2001-09-19 23:08 ` Luigi Genoni
2001-09-19 23:07 ` Luigi Genoni
2001-09-20 6:57 ` john slee
2001-09-21 15:49 ` Gábor Lénárt
2001-09-18 21:39 Liakakis Kostas
2001-09-19 13:08 ` Re[2]: " VDA
2001-09-19 13:41 ` Liakakis Kostas
2001-09-19 13:47 ` Thomas Langås
2001-09-19 14:31 ` Liakakis Kostas
2001-09-19 14:55 ` Jan Niehusmann
2001-09-19 14:57 ` Liakakis Kostas
2001-09-19 18:12 ` Alan Cox
2001-09-19 16:00 ` Linus Torvalds
2001-09-19 17:15 ` safemode
2001-09-19 23:41 ` Nicholas Knight
2001-09-20 15:10 ` Marek Mentel
2001-09-19 18:43 ` Dan Hollis
2001-09-19 18:58 ` Roberto Jung Drebes
2001-09-21 0:46 ` Pavel Machek
2001-09-20 0:19 ` Nicholas Knight
2001-09-20 9:54 ` Liakakis Kostas
2001-09-19 23:04 ` Luigi Genoni
2001-09-19 14:05 ` Tom Diehl
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