From: Jun Sun <jsun@mvista.com>
To: Ralf Baechle <ralf@oss.sgi.com>
Cc: linux-mips@oss.sgi.com
Subject: Re: FPU emulator unsafe for SMP?
Date: Thu, 14 Feb 2002 23:20:30 -0800 [thread overview]
Message-ID: <20020214232030.A3601@mvista.com> (raw)
In-Reply-To: <20020215031118.B21011@dea.linux-mips.net>; from ralf@oss.sgi.com on Fri, Feb 15, 2002 at 03:11:18AM +0100
On Fri, Feb 15, 2002 at 03:11:18AM +0100, Ralf Baechle wrote:
> On Thu, Feb 14, 2002 at 05:56:31PM -0800, Jun Sun wrote:
>
> > I have been chasing a FPU register corruption problem on a SMP box. The
> > curruption seems to be caused by FPU emulator code. Is that code SMP safe?
> > If not, what are the volunerable spots?
> >
> > Just thought I'd check before I dive into it ....
>
> In theory the fp emulation code should be MP safe as the full emulation
> is only accessing it's context in the fp register set of struct
> task_struct. The 32-bit kernel's fp register switching is entirely broken
> (read: close to non-existant). Lots of brownie points for somebody to
> backport that from the 64-bit kernel to the 32-bit kernel and forward
> port all the FPU emu bits to the 64-bit kernel ...
>
Brownie sounds good. :-) So what is the "fp register switching" you are
referring to? There is set of code related to lazy fpu context switch,
which seems to be working fine now.
Jun
next prev parent reply other threads:[~2002-02-15 8:20 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-02-15 1:56 FPU emulator unsafe for SMP? Jun Sun
2002-02-15 2:11 ` Ralf Baechle
2002-02-15 7:20 ` Jun Sun [this message]
2002-02-15 8:30 ` Jun Sun
2002-02-15 9:59 ` Kevin D. Kissell
2002-02-15 9:59 ` Kevin D. Kissell
2002-02-19 22:05 ` Jun Sun
2002-02-19 22:19 ` Ralf Baechle
2002-02-20 0:08 ` Kevin D. Kissell
2002-02-20 0:08 ` Kevin D. Kissell
2002-02-20 1:12 ` Jun Sun
2002-02-20 3:28 ` Greg Lindahl
2002-02-20 4:24 ` Jun Sun
2002-02-20 4:32 ` Daniel Jacobowitz
2002-02-20 9:48 ` Jun Sun
2002-02-20 10:14 ` Kevin D. Kissell
2002-02-20 10:14 ` Kevin D. Kissell
2002-02-20 13:50 ` Ralf Baechle
2002-02-20 20:53 ` Greg Lindahl
2002-02-20 13:24 ` Ralf Baechle
2002-02-20 4:48 ` Greg Lindahl
2002-02-20 9:27 ` Florian Lohoff
2002-02-20 13:18 ` Ralf Baechle
2002-02-20 9:56 ` Geert Uytterhoeven
2002-02-20 11:14 ` Kevin D. Kissell
2002-02-20 13:10 ` Ralf Baechle
2002-02-20 8:27 ` Dominic Sweetman
2002-02-20 9:30 ` Florian Lohoff
2002-02-20 13:56 ` Ralf Baechle
2002-02-20 13:09 ` Ralf Baechle
2002-02-20 14:42 ` Kevin D. Kissell
2002-02-20 14:42 ` Kevin D. Kissell
2002-02-20 14:46 ` Maciej W. Rozycki
2002-02-20 15:05 ` Ralf Baechle
2002-02-20 15:45 ` Maciej W. Rozycki
2002-02-20 13:03 ` Ralf Baechle
2002-02-15 8:14 ` Kevin D. Kissell
2002-02-15 8:14 ` Kevin D. Kissell
2002-02-15 10:57 ` Ralf Baechle
2002-02-19 22:02 ` Jun Sun
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