Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 30 Nov 2002 15:30:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 30 Nov 2002 15:30:11 -0500 Received: from p508B5AB3.dip.t-dialin.net ([80.139.90.179]:20932 "EHLO dea.linux-mips.net") by vger.kernel.org with ESMTP id ; Sat, 30 Nov 2002 15:30:10 -0500 Date: Sat, 30 Nov 2002 21:34:31 +0100 From: Ralf Baechle To: Andi Kleen Cc: davidm@hpl.hp.com, Stephen Rothwell , Linus , LKML , anton@samba.org, "David S. Miller" , schwidefsky@de.ibm.com, willy@debian.org Subject: Re: [PATCH] Start of compat32.h (again) Message-ID: <20021130213431.C27776@linux-mips.org> References: <20021127184228.2f2e87fd.sfr@canb.auug.org.au> <15844.31669.896101.983575@napali.hpl.hp.com> <20021127082918.GA5227@averell> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <20021127082918.GA5227@averell>; from ak@muc.de on Wed, Nov 27, 2002 at 09:29:18AM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 863 Lines: 20 On Wed, Nov 27, 2002 at 09:29:18AM +0100, Andi Kleen wrote: > > That is not a safe assumption. The ia64 ABI requires that a 32-bit > > result is returned in the least-significant 32 bits only---the upper > > 32 bits may contain garbage. It should be safe to declare the syscall > > return type always as "long", no? > > But the 32bit user space surely doesn't care about any garbage in > the upper 32bits, no ? It does. With very few exceptions all 32-bit instructions on MIPS require that all the register values are properly sign extended to 64-bit or the operation of those instructions is undefined. Ralf - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/