From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH v2] ARM: Define wfi() macro for v6 processors Date: Tue, 8 Feb 2011 17:47:18 +0100 Message-ID: <201102081747.18674.arnd@arndb.de> References: <1297162885-2975-1-git-send-email-dave.martin@linaro.org> <201102081615.15713.arnd@arndb.de> <20110208162515.GB6188@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from moutng.kundenserver.de ([212.227.126.186]:57184 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755024Ab1BHQr2 (ORCPT ); Tue, 8 Feb 2011 11:47:28 -0500 In-Reply-To: <20110208162515.GB6188@n2100.arm.linux.org.uk> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Russell King - ARM Linux Cc: Dave Martin , linux-arm-kernel@lists.infradead.org, Nicolas Pitre , Tony Lindgren , Santosh Shilimkar , linux-omap@vger.kernel.org, Jean Pihet On Tuesday 08 February 2011 17:25:16 Russell King - ARM Linux wrote: > On Tue, Feb 08, 2011 at 04:15:15PM +0100, Arnd Bergmann wrote: > > But that doesn't work if you build a combined v5/v6/v7 kernel, because > > v5 supports neither form, right? I think to do that, it needs the > > same kind of abstraction that we have for a number of other things > > like cache management in arch/arm/mm/. > > The options are kernels which support v3-v5 or v6-v7. There's too big > a change between v5 and v6 to combine those into one kernel. Ah, good to know. I never realized this with the common binary discussions. Building for the versatile/realview platform makes it possible to select any of ARM926 and the v6/v6k/v7 CPUs, as well as ARM7TDMI in the same kernel config, so I assumed that this was actually a valid configuration aside from bugs. Would an attempt to make a combined v5/v6 kernel result in unacceptably bad code, or is this just too much work for anyone to be bothered with and little practical value? Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Tue, 8 Feb 2011 17:47:18 +0100 Subject: [PATCH v2] ARM: Define wfi() macro for v6 processors In-Reply-To: <20110208162515.GB6188@n2100.arm.linux.org.uk> References: <1297162885-2975-1-git-send-email-dave.martin@linaro.org> <201102081615.15713.arnd@arndb.de> <20110208162515.GB6188@n2100.arm.linux.org.uk> Message-ID: <201102081747.18674.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tuesday 08 February 2011 17:25:16 Russell King - ARM Linux wrote: > On Tue, Feb 08, 2011 at 04:15:15PM +0100, Arnd Bergmann wrote: > > But that doesn't work if you build a combined v5/v6/v7 kernel, because > > v5 supports neither form, right? I think to do that, it needs the > > same kind of abstraction that we have for a number of other things > > like cache management in arch/arm/mm/. > > The options are kernels which support v3-v5 or v6-v7. There's too big > a change between v5 and v6 to combine those into one kernel. Ah, good to know. I never realized this with the common binary discussions. Building for the versatile/realview platform makes it possible to select any of ARM926 and the v6/v6k/v7 CPUs, as well as ARM7TDMI in the same kernel config, so I assumed that this was actually a valid configuration aside from bugs. Would an attempt to make a combined v5/v6 kernel result in unacceptably bad code, or is this just too much work for anyone to be bothered with and little practical value? Arnd