From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751753AbbAVKE7 (ORCPT ); Thu, 22 Jan 2015 05:04:59 -0500 Received: from foss-mx-na.foss.arm.com ([217.140.108.86]:40786 "EHLO foss-mx-na.foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750792AbbAVKEw (ORCPT ); Thu, 22 Jan 2015 05:04:52 -0500 Date: Thu, 22 Jan 2015 10:04:41 +0000 From: Catalin Marinas To: Sergey Dyasly Cc: "linux-arm-kernel@lists.infradead.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Russell King , Guan Xuetao , "nicolas.pitre@linaro.org" , James Bottomley , Will Deacon , Arnd Bergmann , Andrew Morton , Dmitry Safonov Subject: Re: [PATCH] ARM: use default ioremap alignment for SMP or LPAE Message-ID: <20150122100441.GA19811@e104818-lin.cambridge.arm.com> References: <1421911075-8814-1-git-send-email-s.dyasly@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1421911075-8814-1-git-send-email-s.dyasly@samsung.com> 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 Thu, Jan 22, 2015 at 07:17:55AM +0000, Sergey Dyasly wrote: > 16MB alignment for ioremap mappings was added by commit a069c896d0d6 ("[ARM] > 3705/1: add supersection support to ioremap()") in order to support supersection > mappings. But __arm_ioremap_pfn_caller uses section and supersection mappings > only in !SMP && !LPAE case. There is no need for such big alignment if either > SMP or LPAE is enabled. [...] > diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h > index 184def0..c3ef139 100644 > --- a/arch/arm/include/asm/memory.h > +++ b/arch/arm/include/asm/memory.h > @@ -78,10 +78,12 @@ > */ > #define XIP_VIRT_ADDR(physaddr) (MODULES_VADDR + ((physaddr) & 0x000fffff)) > > +#if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) > /* > * Allow 16MB-aligned ioremap pages > */ > #define IOREMAP_MAX_ORDER 24 > +#endif Actually, I think we could make this depend only on CONFIG_IO_36. That's the only scenario where we get the supersections matter, and maybe make CONFIG_IO_36 dependent on !SMP or !ARM_LPAE. My assumption is that we don't support single zImage with CPU_XSC3 enabled (but I haven't followed the latest developments here). -- Catalin