From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754407Ab3LPOnI (ORCPT ); Mon, 16 Dec 2013 09:43:08 -0500 Received: from fw-tnat.austin.arm.com ([217.140.110.23]:39390 "EHLO highbank-bc01-b06.austin.arm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753859Ab3LPOnH (ORCPT ); Mon, 16 Dec 2013 09:43:07 -0500 Date: Mon, 16 Dec 2013 14:42:46 +0000 From: Catalin Marinas To: Mark Salter Cc: "linux-kernel@vger.kernel.org" , Leif Lindholm , Will Deacon , Rob Landley , "linux-arm-kernel@lists.infradead.org" , "linux-doc@vger.kernel.org" Subject: Re: [PATCH 4/4] arm64: add early_ioremap support Message-ID: <20131216144246.GG17713@arm.com> References: <1385606679-30446-1-git-send-email-msalter@redhat.com> <1385606679-30446-5-git-send-email-msalter@redhat.com> <20131205162800.GB1495@darko.cambridge.arm.com> <1386350449.1861.196.camel@deneb.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1386350449.1861.196.camel@deneb.redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 06, 2013 at 05:20:49PM +0000, Mark Salter wrote: > On Thu, 2013-12-05 at 16:28 +0000, Catalin Marinas wrote: > > On Thu, Nov 28, 2013 at 02:44:39AM +0000, Mark Salter wrote: > > > + * These 'compile-time allocated' memory buffers are > > > + * page-sized. Use set_fixmap(idx,phys) to associate > > > + * physical memory with fixmap indices. > > > + * > > > + */ > > > +enum fixed_addresses { > > > + FIX_EARLYCON, > > > + __end_of_permanent_fixed_addresses, > > > + > > > + /* > > > + * Temporary boot-time mappings, used by early_ioremap(), > > > + * before ioremap() is functional. > > > + */ > > > > How temporary are this mappings? The early console may not be disabled > > at run-time, so it still needs the mapping. > > It varies by arch, but we have flexibility on arm64 because there is a > dedicated pmd which stays around forever. So, you see the FIX_EARLYCON > above is a "permanent" mapping which isn't really an early_ioremap > mapping. The earlyprintk code uses set_fixmap_io. I suppose this could > have been broken up into two patches, one fixmap, and one early_ioremap. > To answer your concern, the earlyprintk mapping doesn't go away. The > early_ioremap mappings should be temporary and there's a checker for > that which is run at late_initcall time. OK, thanks for clarification, I don't think it's worth splitting the patch. -- Catalin