From: Jamie Lokier <jamie@shareable.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Petr Vandrovec <vandrove@vc.cvut.cz>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: TSCs are a no-no on i386
Date: Thu, 31 Jul 2003 19:37:30 +0100 [thread overview]
Message-ID: <20030731183730.GA7803@mail.jlokier.co.uk> (raw)
In-Reply-To: <1059667304.16608.47.camel@dhcp22.swansea.linux.org.uk>
Alan Cox wrote:
> > > And if the byte you are looking at was patched by another thread you've
> > > blown it. Your emulation can only be so good 8) People do stuff like
> > > patching instructions under software decode as a robustness check - its
> > > normally pretty amusing
> >
> > On a uniprocessor 386, this is not a problem. Just disable preemption
> > in the kernel decoder.
>
> Wrong again. Thats a common myth but you see I can put the instruction on a page
> so that its executed from a page I just did a read() into in another process. If
> I'm really bored I'll use O_DIRECT but thats mostly for makign life really bad
> for non cache coherent setups 8)
I wouldn't be surprised if even real CPUs mis-decode when there's a
concurrent DMA into the area they are reading instructions from! :)
-- Jamie
next prev parent reply other threads:[~2003-07-31 18:37 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-30 13:56 TSCs are a no-no on i386 Jan-Benedict Glaw
2003-07-30 14:18 ` Maciej W. Rozycki
2003-07-30 14:44 ` Jan-Benedict Glaw
2003-07-30 16:58 ` Matthew Garrett
2003-07-30 17:19 ` Alan Cox
2003-07-30 18:10 ` Adrian Bunk
2003-07-30 18:30 ` Mike Fedyk
2003-07-30 18:45 ` Adrian Bunk
2003-07-30 20:01 ` Alan Cox
2003-07-30 20:33 ` Jan-Benedict Glaw
2003-07-30 22:19 ` J.A. Magallon
2003-07-31 6:11 ` Jan-Benedict Glaw
2003-07-30 23:05 ` Alan Cox
2003-07-31 11:11 ` Richard B. Johnson
2003-07-31 11:26 ` Emulating i486+ insn on i386 (was: TSCs are a no-no on i386) Jan-Benedict Glaw
2003-07-31 11:41 ` TSCs are a no-no on i386 Jan-Benedict Glaw
2003-07-31 0:22 ` Adrian Bunk
2003-07-31 6:22 ` Jan-Benedict Glaw
2003-07-31 7:17 ` Willy Tarreau
2003-07-31 11:38 ` Emulating i486 on i386 (was: TSCs are a no-no on i386) Jan-Benedict Glaw
2003-07-31 11:51 ` Alan Cox
2003-07-31 12:14 ` Jan-Benedict Glaw
2003-07-31 13:01 ` Jan-Benedict Glaw
2003-07-31 15:09 ` Martin Schlemmer
2003-07-31 15:33 ` Jan-Benedict Glaw
2003-08-01 5:37 ` Martin Schlemmer
2003-07-31 15:12 ` Jamie Lokier
2003-07-31 15:32 ` Jan-Benedict Glaw
2003-07-31 15:07 ` TSCs are a no-no on i386 Jamie Lokier
2003-07-31 15:23 ` Willy Tarreau
2003-07-31 15:50 ` Richard B. Johnson
2003-07-31 16:24 ` Jan-Benedict Glaw
2003-08-06 11:08 ` Pavel Machek
2003-08-06 14:33 ` Maciej W. Rozycki
2003-07-30 20:28 ` Jan-Benedict Glaw
2003-07-30 21:50 ` Petr Vandrovec
2003-07-30 23:10 ` Alan Cox
2003-07-31 15:10 ` Jamie Lokier
2003-07-31 16:01 ` Alan Cox
2003-07-31 18:37 ` Jamie Lokier [this message]
2003-07-31 19:10 ` Alan Cox
2003-07-31 6:29 ` Jan-Benedict Glaw
2003-07-30 20:27 ` Jan-Benedict Glaw
2003-08-06 16:41 James Bottomley
2003-08-06 16:45 James Bottomley
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