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From: Ralf Baechle <ralf@linux-mips.org>
To: Lluis Batlle i Rossell <viric@viric.name>
Cc: linux-mips@linux-mips.org, loongson-dev@googlegroups.com
Subject: Re: [PATCH] MIPS: Add emulation for fpureg-mem unaligned access
Date: Tue, 31 Jul 2012 15:40:01 +0200	[thread overview]
Message-ID: <20120731134001.GA14151@linux-mips.org> (raw)
In-Reply-To: <20120615234641.6938B58FE7C@mail.viric.name>

On Sat, Jun 16, 2012 at 12:22:53AM +0200, Lluis Batlle i Rossell wrote:

> Reusing most of the code from lw,ld,sw,sd emulation,
> I add the emulation for lwc1,ldc1,swc1,sdc1.
> 
> This avoids the direct SIGBUS sent to userspace processes that have
> misaligned memory accesses.
> 
> I've tested the change in Loongson2F, with an own test program, and
> WebKit 1.4.0, as both were killed by sigbus without this patch.

A misaligned FPU access is a strong indication for broken, non-portable
software.  which means you're likely trying to fix the wrong issue.  It's
quite intentional that there is no unaligned handling for the FPU in the
kernel - and afaics there isn't for any other MIPS UNIX.

  Ralf

  parent reply	other threads:[~2012-07-31 13:40 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-15 22:22 [PATCH] MIPS: Add emulation for fpureg-mem unaligned access Lluis Batlle i Rossell
2012-06-16 11:21 ` Jonas Gorski
2012-06-16 12:15   ` Lluís Batlle i Rossell
2012-06-16 12:40     ` [loongson-dev] " Lluís Batlle i Rossell
2012-06-20 19:05       ` Lluís Batlle i Rossell
2012-07-11  0:05         ` Maciej W. Rozycki
2012-07-30 19:47           ` Lluís Batlle i Rossell
2012-07-30 23:56             ` Maciej W. Rozycki
2012-06-16 12:58     ` Lluís Batlle i Rossell
2012-06-17  9:09       ` Thomas Bogendoerfer
2012-07-31 13:40 ` Ralf Baechle [this message]
2012-07-31 14:07   ` Lluís Batlle i Rossell
2012-07-31 15:10     ` Ralf Baechle

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