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 16:10:20 +0100 [thread overview]
Message-ID: <20030731151020.GF6410@mail.jlokier.co.uk> (raw)
In-Reply-To: <1059606394.10505.24.camel@dhcp22.swansea.linux.org.uk>
Alan Cox wrote:
> On Mer, 2003-07-30 at 22:50, Petr Vandrovec wrote:
> > There is no such instruction. Skip LOCK prefix and decode again,
> > you'll get either cmpxchg or xadd (or cmpxchg8b, but then it does
> > not work on i486 too).
>
> 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.
Of course if you do it in userspace using SIGILL, then it is broken :)
-- Jamie
next prev parent reply other threads:[~2003-07-31 15:12 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 [this message]
2003-07-31 16:01 ` Alan Cox
2003-07-31 18:37 ` Jamie Lokier
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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