From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 06 Jul 2006 23:57:36 +0100 (BST) Received: from localhost.localdomain ([127.0.0.1]:61893 "EHLO bacchus.dhis.org") by ftp.linux-mips.org with ESMTP id S3489839AbWGFW50 (ORCPT ); Thu, 6 Jul 2006 23:57:26 +0100 Received: from denk.linux-mips.net (denk.linux-mips.net [127.0.0.1]) by bacchus.dhis.org (8.13.6/8.13.4) with ESMTP id k66MvMSx018434; Thu, 6 Jul 2006 23:57:22 +0100 Received: (from ralf@localhost) by denk.linux-mips.net (8.13.6/8.13.6/Submit) id k66MvIG9018433; Thu, 6 Jul 2006 23:57:18 +0100 Date: Thu, 6 Jul 2006 23:57:18 +0100 From: Ralf Baechle To: Sergei Shtylyov Cc: Linux-MIPS , a.voropay@equant.ru Subject: Re: [PATCH] Fix process crash in 2.4 on attempt to use FPU on MIPS32 Message-ID: <20060706225718.GA18284@linux-mips.org> References: <44AD7FBA.8000203@ru.mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <44AD7FBA.8000203@ru.mvista.com> User-Agent: Mutt/1.4.2.1i Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 11928 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Fri, Jul 07, 2006 at 01:25:14AM +0400, Sergei Shtylyov wrote: > If there's built-in FPU in a MIPS32 CPU the first time the process tries > to use it, the kernel should crash with "reserved instruction" -- CPU will > try > to execute 'dmtc1' which is a MIPS64 only insn. _init_fpu() was apprently > blindly copied form arch/mips64/... :-) > > Since this occured with GXemul recently resending this 1.5 year old patch. I didn't like the patch back then because it drops the optimizations for 64-bit processors. So I just took the 2.6 variant of the code and bolted it into 2.4. Ralf