From: Ralf Baechle <ralf@oss.sgi.com>
To: Jun Sun <jsun@mvista.com>
Cc: linux-mips@oss.sgi.com
Subject: Re: FPU emulator unsafe for SMP?
Date: Fri, 15 Feb 2002 03:11:18 +0100 [thread overview]
Message-ID: <20020215031118.B21011@dea.linux-mips.net> (raw)
In-Reply-To: <3C6C6ACF.CAD2FFC@mvista.com>; from jsun@mvista.com on Thu, Feb 14, 2002 at 05:56:31PM -0800
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 ...
> BTW, I think even with the latest fpu emu patch, the classic fpu/signal
> problem is still there. I will post in a separate email later.
Urgs ...
Ralf
next prev parent reply other threads:[~2002-02-15 3:14 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 [this message]
2002-02-15 7:20 ` Jun Sun
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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