From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Mon, 21 Apr 2008 17:12:54 +0100 (BST) Received: from oss.sgi.com ([192.48.170.157]:58804 "EHLO oss.sgi.com") by ftp.linux-mips.org with ESMTP id S20040672AbYDUQMv (ORCPT ); Mon, 21 Apr 2008 17:12:51 +0100 Received: from dl5rb.ham-radio-op.net (localhost [127.0.0.1]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id m3LGBrp8001253 for ; Mon, 21 Apr 2008 09:12:00 -0700 Received: from denk.linux-mips.net (denk.linux-mips.net [127.0.0.1]) by dl5rb.ham-radio-op.net (8.14.1/8.13.8) with ESMTP id m3LGCNMr004515; Mon, 21 Apr 2008 17:12:23 +0100 Received: (from ralf@localhost) by denk.linux-mips.net (8.14.1/8.14.1/Submit) id m3LGCLag004501; Mon, 21 Apr 2008 17:12:21 +0100 Date: Mon, 21 Apr 2008 17:12:21 +0100 From: Ralf Baechle To: David Daney Cc: Atsushi Nemoto , linux-mips@linux-mips.org Subject: Re: [MIPS] Fix handling of trap and breakpoint instructions Message-ID: <20080421161221.GA21641@linux-mips.org> References: <20080421.100721.07644724.nemoto@toshiba-tops.co.jp> <480CB728.7060402@avtrex.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <480CB728.7060402@avtrex.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-Virus-Scanned: ClamAV 0.91.2/6021/Wed Feb 27 15:55:48 2008 on oss.sgi.com X-Virus-Status: Clean 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: 18983 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 Mon, Apr 21, 2008 at 08:47:52AM -0700, David Daney wrote: > Note that there has been some confusion about break codes in gas over the > years. Ancient versions (I am not sure which) generated different break > codes than recent versions. > > Before changing it make sure that you don't break existing user space code. > > One problem (fixed around 2.4.25 or so) was the integer division by zero in > user space would result in SIGTRAP instead of SIGFPE. If you change the > break code handling you should verify that you don't break this. Not quite correct. Very old and recent binutils are bug compatible. It's middle age gcc which unfortunately fixed the bug creating a bug ;-) Ralf