From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: Re: [PATCH 0/4] Hacks to allow booting ARM SMP kernel on UP ARMv7 Date: Mon, 06 Sep 2010 11:39:42 +0100 Message-ID: <1283769582.1926.11.camel@e102109-lin.cambridge.arm.com> References: <4C6CFBAF.6020407@canonical.com> <20100819095705.GU12184@atomide.com> <20100819102025.GA32151@n2100.arm.linux.org.uk> <20100820120622.GL25742@atomide.com> <20100830225527.GC11597@atomide.com> <20100902133637.GJ26319@n2100.arm.linux.org.uk> <20100902161659.GJ11597@atomide.com> <1283765333.1926.2.camel@e102109-lin.cambridge.arm.com> <20100906093424.GB20903@n2100.arm.linux.org.uk> <1283765910.1926.4.camel@e102109-lin.cambridge.arm.com> <20100906100632.GC20903@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:42438 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752430Ab0IFKjx (ORCPT ); Mon, 6 Sep 2010 06:39:53 -0400 In-Reply-To: <20100906100632.GC20903@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: Tony Lindgren , linux-omap@vger.kernel.org, Will Deacon , linux-arm-kernel@lists.infradead.org, Bryan Wu On Mon, 2010-09-06 at 11:06 +0100, Russell King - ARM Linux wrote: > On Mon, Sep 06, 2010 at 10:38:30AM +0100, Catalin Marinas wrote: > > On Mon, 2010-09-06 at 10:34 +0100, Russell King - ARM Linux wrote: > > > On Mon, Sep 06, 2010 at 10:28:53AM +0100, Catalin Marinas wrote: > > > > I haven't followed your patches closely but can we restrict the ARMv6 > > > > SMP/UP support to only those cores that have TEX remapping (most of them > > > > probably)? > > > > > > We don't support TEX remapping on ARMv6. > > > > I know but it's easy to enable if useful for the SMP/UP v6/v7 > > combination (with some restrictions). > > It'll make proc-v6.S much more complicated than it already is, requiring > it to carry both the non-remap and remapping code selected via an ifdef. > > Is it worth it? For the sake of one conditional in mmu.c, I don't think > so - and the view is that using TEX remapping to get rid of the shared > bit is a horrible hack anyway. > > In any case, it's unnecessary. We can use my word-replacement to modify > a variable to indicate whether we're running on SMP or not, and so have > the test for SMP-on-UP in just one place. Like this: It looks fine to me. Thanks. -- Catalin From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Mon, 06 Sep 2010 11:39:42 +0100 Subject: [PATCH 0/4] Hacks to allow booting ARM SMP kernel on UP ARMv7 In-Reply-To: <20100906100632.GC20903@n2100.arm.linux.org.uk> References: <4C6CFBAF.6020407@canonical.com> <20100819095705.GU12184@atomide.com> <20100819102025.GA32151@n2100.arm.linux.org.uk> <20100820120622.GL25742@atomide.com> <20100830225527.GC11597@atomide.com> <20100902133637.GJ26319@n2100.arm.linux.org.uk> <20100902161659.GJ11597@atomide.com> <1283765333.1926.2.camel@e102109-lin.cambridge.arm.com> <20100906093424.GB20903@n2100.arm.linux.org.uk> <1283765910.1926.4.camel@e102109-lin.cambridge.arm.com> <20100906100632.GC20903@n2100.arm.linux.org.uk> Message-ID: <1283769582.1926.11.camel@e102109-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, 2010-09-06 at 11:06 +0100, Russell King - ARM Linux wrote: > On Mon, Sep 06, 2010 at 10:38:30AM +0100, Catalin Marinas wrote: > > On Mon, 2010-09-06 at 10:34 +0100, Russell King - ARM Linux wrote: > > > On Mon, Sep 06, 2010 at 10:28:53AM +0100, Catalin Marinas wrote: > > > > I haven't followed your patches closely but can we restrict the ARMv6 > > > > SMP/UP support to only those cores that have TEX remapping (most of them > > > > probably)? > > > > > > We don't support TEX remapping on ARMv6. > > > > I know but it's easy to enable if useful for the SMP/UP v6/v7 > > combination (with some restrictions). > > It'll make proc-v6.S much more complicated than it already is, requiring > it to carry both the non-remap and remapping code selected via an ifdef. > > Is it worth it? For the sake of one conditional in mmu.c, I don't think > so - and the view is that using TEX remapping to get rid of the shared > bit is a horrible hack anyway. > > In any case, it's unnecessary. We can use my word-replacement to modify > a variable to indicate whether we're running on SMP or not, and so have > the test for SMP-on-UP in just one place. Like this: It looks fine to me. Thanks. -- Catalin