From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vineet Gupta Subject: Re: [RFC Patch v1 45/55] ARC: unaligned access emulation Date: Thu, 20 Dec 2012 16:00:19 +0530 Message-ID: <50D2E8BB.6000108@synopsys.com> References: <1352720953-24321-1-git-send-email-vgupta@synopsys.com> <1352720953-24321-15-git-send-email-vgupta@synopsys.com> <201211121400.13046.arnd@arndb.de> <50D2B75A.3000208@synopsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: 7bit Return-path: Received: from us02smtp1.synopsys.com ([198.182.60.75]:35683 "EHLO vaxjo.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751326Ab2LTKad (ORCPT ); Thu, 20 Dec 2012 05:30:33 -0500 In-Reply-To: <50D2B75A.3000208@synopsys.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Arnd Bergmann Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, Jonathan Corbet On Thursday 20 December 2012 12:29 PM, Vineet Gupta wrote: > On Monday 12 November 2012 07:30 PM, Arnd Bergmann wrote: >> On Monday 12 November 2012, Vineet.Gupta1@synopsys.com wrote: >>> + >>> +config ARC_MISALIGN_ACCESS >>> + bool "Emulate unaligned memory access (userspace only)" >>> + default N >>> + help >>> + This enables misaligned 16 & 32 bit memory access from user space. >>> + Use ONLY-IF-ABS-NECESSARY as it will be very slow and also can hide >>> + potential bugs in code >> >> parisc and ia64 both have the same feature, and they use sysctl to configure >> it at run-time. Maybe you should pick one of the two sysctl implementations >> and hook that up to your implementation as well. > > Sounds like a good idea. > > Looking at your suggestion, the sysctl interface in both of those is for > slightly different semantics and ARC would possibly need a bit from > both. So to avoid duplication, I'm proposing following changes to > kernel/sysctl.c and the generic options selected by respective arches. > > * no_unaligned_warning:CONFIG_IA64 => CONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN > *unaligned_enabled: __hppa__ => CONFIG_SYSCTL_ARCH_UNALIGN_ALLOW > > If you can think of better(smaller) names, please do let me know :-) > > If we agree in principle, I'll cookup the patches and seek the ACKs from > ARCH maintainers (assuming my CC list above is right). And to keep > things simple, we can route the kernel/sysctl.c changes via the ARC > submission tree. > > Thx, > Vineet > Sorry for a naive patch submitter question (yes I've already read SubmittingPatches and googled much already). A lot of times, I see the "Cc: ..." lines, just below the "Signed-off-by:" lines in the patch - e.g. https://lkml.org/lkml/2012/10/4/318 Are those added manually - because none of the xxx-cc options to format-patch or send-email seem to be doing that - unless I missed some. Context: I have the patch which touches ia64/parisc which I want to send out and at the same time have those "Cc: lines for the maintainers too" Thx, -Vineet * It's OK to "look" fool once - rather than actually "being" a fool rest of your life !