From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932897AbcLGQ7a (ORCPT ); Wed, 7 Dec 2016 11:59:30 -0500 Received: from foss.arm.com ([217.140.101.70]:42826 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932859AbcLGQ71 (ORCPT ); Wed, 7 Dec 2016 11:59:27 -0500 Date: Wed, 7 Dec 2016 16:59:13 +0000 From: Catalin Marinas To: Yury Norov Cc: linux-doc@vger.kernel.org, szabolcs.nagy@arm.com, heiko.carstens@de.ibm.com, cmetcalf@ezchip.com, philipp.tomsich@theobroma-systems.com, joseph@codesourcery.com, linux-arch@vger.kernel.org, zhouchengming1@huawei.com, Prasun.Kapoor@caviumnetworks.com, agraf@suse.de, geert@linux-m68k.org, kilobyte@angband.pl, manuel.montezelo@gmail.com, arnd@arndb.de, pinskia@gmail.com, linyongting@huawei.com, klimov.linux@gmail.com, broonie@kernel.org, bamvor.zhangjian@huawei.com, Bamvor Zhang Jian , linux-arm-kernel@lists.infradead.org, maxim.kuvyrkov@linaro.org, Nathan_Lynch@mentor.com, linux-kernel@vger.kernel.org, schwidefsky@de.ibm.com, davem@davemloft.net, christoph.muellner@theobroma-systems.com Subject: Re: [PATCH 16/18] arm64: ptrace: handle ptrace_request differently for aarch32 and ilp32 Message-ID: <20161207165913.GD31779@e104818-lin.cambridge.arm.com> References: <1477081997-4770-1-git-send-email-ynorov@caviumnetworks.com> <1477081997-4770-17-git-send-email-ynorov@caviumnetworks.com> <20161205163422.GG14429@e104818-lin.cambridge.arm.com> <20161206062508.GA17835@yury-N73SV> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161206062508.GA17835@yury-N73SV> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 06, 2016 at 11:55:08AM +0530, Yury Norov wrote: > On Mon, Dec 05, 2016 at 04:34:23PM +0000, Catalin Marinas wrote: > > On Fri, Oct 21, 2016 at 11:33:15PM +0300, Yury Norov wrote: > > > New aarch32 ptrace syscall handler is introduced to avoid run-time > > > detection of the task type. > > > > What's wrong with the run-time detection? If it's just to avoid a > > negligible overhead, I would rather keep the code simpler by avoiding > > duplicating the generic compat_sys_ptrace(). > > Nothing wrong. This is how Arnd asked me to do. You already asked this > question: http://lkml.iu.edu/hypermail/linux/kernel/1604.3/00930.html Hmm, I completely forgot about this ;). There is still an advantage to doing run-time checking if we avoid touching core code (less acks to gather and less code duplication). Let's see what Arnd says but the initial patch looked simpler. -- Catalin From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Wed, 7 Dec 2016 16:59:13 +0000 Subject: [PATCH 16/18] arm64: ptrace: handle ptrace_request differently for aarch32 and ilp32 In-Reply-To: <20161206062508.GA17835@yury-N73SV> References: <1477081997-4770-1-git-send-email-ynorov@caviumnetworks.com> <1477081997-4770-17-git-send-email-ynorov@caviumnetworks.com> <20161205163422.GG14429@e104818-lin.cambridge.arm.com> <20161206062508.GA17835@yury-N73SV> Message-ID: <20161207165913.GD31779@e104818-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Dec 06, 2016 at 11:55:08AM +0530, Yury Norov wrote: > On Mon, Dec 05, 2016 at 04:34:23PM +0000, Catalin Marinas wrote: > > On Fri, Oct 21, 2016 at 11:33:15PM +0300, Yury Norov wrote: > > > New aarch32 ptrace syscall handler is introduced to avoid run-time > > > detection of the task type. > > > > What's wrong with the run-time detection? If it's just to avoid a > > negligible overhead, I would rather keep the code simpler by avoiding > > duplicating the generic compat_sys_ptrace(). > > Nothing wrong. This is how Arnd asked me to do. You already asked this > question: http://lkml.iu.edu/hypermail/linux/kernel/1604.3/00930.html Hmm, I completely forgot about this ;). There is still an advantage to doing run-time checking if we avoid touching core code (less acks to gather and less code duplication). Let's see what Arnd says but the initial patch looked simpler. -- Catalin