From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: + preadv-pwritev-add-preadv-and-pwritev-system-calls.patch added to -mm tree Date: Wed, 04 Feb 2009 16:42:48 -0800 Message-ID: <498A3608.3010008@zytor.com> References: <200902022135.n12LZa1a010673@imap1.linux-foundation.org> <49876A91.4000705@zytor.com> <49881904.30705@redhat.com> <498879B3.8030002@zytor.com> <20090203171559.GA20898@flint.arm.linux.org.uk> <49887EF4.1090300@zytor.com> <20090203174257.GC20898@flint.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090203174257.GC20898@flint.arm.linux.org.uk> Sender: linux-arch-owner@vger.kernel.org To: "H. Peter Anvin" , Gerd Hoffmann , akpm@linux-foundation.org, mm-commits@vger.kernel.org, arnd@arndb.de, linux-api@vger.kernel.org, linux-arch@vger.k List-Id: linux-api@vger.kernel.org Russell King wrote: > > This is an overly simplified view of things. There exist syscalls where > it's not just a matter of padding, but instead where the chosen argument > order interacts with the ABI padding requirements to produce something > which the syscall interface can't handle. There are two solutions to > that: reorder the syscall arguments or split them up into 32-bit high/low > quantities. > I just went back and looked specifically at this, and I wonder if you could be more concrete. In particular, this seems to imply a rule somewhere which could probably be improved reasonably easily. -hpa From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from terminus.zytor.com ([198.137.202.10]:60333 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761424AbZBEAnw (ORCPT ); Wed, 4 Feb 2009 19:43:52 -0500 Message-ID: <498A3608.3010008@zytor.com> Date: Wed, 04 Feb 2009 16:42:48 -0800 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: + preadv-pwritev-add-preadv-and-pwritev-system-calls.patch added to -mm tree References: <200902022135.n12LZa1a010673@imap1.linux-foundation.org> <49876A91.4000705@zytor.com> <49881904.30705@redhat.com> <498879B3.8030002@zytor.com> <20090203171559.GA20898@flint.arm.linux.org.uk> <49887EF4.1090300@zytor.com> <20090203174257.GC20898@flint.arm.linux.org.uk> In-Reply-To: <20090203174257.GC20898@flint.arm.linux.org.uk> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: "H. Peter Anvin" , Gerd Hoffmann , akpm@linux-foundation.org, mm-commits@vger.kernel.org, arnd@arndb.de, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, mingo@elte.hu, ralf@linux-mips.org, tglx@linutronix.de, viro@zeniv.linux.org.uk Message-ID: <20090205004248.8wDPOT4OcnY2PLLRskXFFoE_3FW1CgbXvL1GsROZMW0@z> Russell King wrote: > > This is an overly simplified view of things. There exist syscalls where > it's not just a matter of padding, but instead where the chosen argument > order interacts with the ABI padding requirements to produce something > which the syscall interface can't handle. There are two solutions to > that: reorder the syscall arguments or split them up into 32-bit high/low > quantities. > I just went back and looked specifically at this, and I wonder if you could be more concrete. In particular, this seems to imply a rule somewhere which could probably be improved reasonably easily. -hpa