From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ftp.linux-mips.org ([194.74.144.162]:42608 "EHLO ftp.linux-mips.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1945910AbXBUXXn (ORCPT ); Wed, 21 Feb 2007 18:23:43 -0500 Received: from localhost.localdomain ([127.0.0.1]:6340 "EHLO dl5rb.ham-radio-op.net") by ftp.linux-mips.org with ESMTP id S20038588AbXBUXXm (ORCPT ); Wed, 21 Feb 2007 23:23:42 +0000 Date: Wed, 21 Feb 2007 23:23:08 +0000 From: Ralf Baechle Subject: Re: [PATCH]add epoll compat code to fsl/compat.c Message-ID: <20070221232308.GA12989@linux-mips.org> References: <20070221102027.52bf703a.sfr@canb.auug.org.au> <20070221120145.419a03ee.sfr@canb.auug.org.au> <20070221141040.1807a368.sfr@canb.auug.org.au> <20070221221449.GE8957@linux-mips.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-arch-owner@vger.kernel.org To: Davide Libenzi Cc: Linus Torvalds , Stephen Rothwell , Andrew Morton , David Woodhouse , linux-arch@vger.kernel.org, rmk@arm.linux.org.uk, tony.luck@intel.com List-ID: On Wed, Feb 21, 2007 at 02:25:09PM -0800, Davide Libenzi wrote: > > doesn't have to care. A few nasty architectures (Afair old ARM and the > > b0rked R5900 in the Playstation 2 for 128-bit integer loads) however > > don't throw exceptions so __get_user / __put_user have to handle the > > problem manually which of course adds considerable overhead to the common > > case. > > Exactly. But at that point it'd better that the code handle the potential > split operation by itself, w/out getting a fault for each mis-aligned > access. For these architectures it's a matter of correctness because ther won't be an exception, so no chance to handle the rare case of missalignment in the slow path. Ralf