From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C34DC433B4 for ; Wed, 14 Apr 2021 05:59:25 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5FCF960240 for ; Wed, 14 Apr 2021 05:59:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5FCF960240 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4FKsHZ5hJHz3c0t for ; Wed, 14 Apr 2021 15:59:22 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=arm.com (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=anshuman.khandual@arm.com; receiver=) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lists.ozlabs.org (Postfix) with ESMTP id 4FKsHC1L5vz2yyK for ; Wed, 14 Apr 2021 15:59:00 +1000 (AEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A4E4B106F; Tue, 13 Apr 2021 22:58:57 -0700 (PDT) Received: from [10.163.72.181] (unknown [10.163.72.181]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E76123F694; Tue, 13 Apr 2021 22:58:50 -0700 (PDT) Subject: Re: [PATCH] mm: Define ARCH_HAS_FIRST_USER_ADDRESS To: Christophe Leroy , linux-mm@kvack.org, akpm@linux-foundation.org References: <1618368899-20311-1-git-send-email-anshuman.khandual@arm.com> From: Anshuman Khandual Message-ID: <6d24d3cc-b2df-f0d7-f4bf-f505f679c77e@arm.com> Date: Wed, 14 Apr 2021 11:29:40 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-s390@vger.kernel.org, linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org, linux-xtensa@linux-xtensa.org, linux-sh@vger.kernel.org, linux-hexagon@vger.kernel.org, x86@kernel.org, linux-um@lists.infradead.org, linux-mips@vger.kernel.org, linux-csky@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, openrisc@lists.librecores.org, linux-alpha@vger.kernel.org, sparclinux@vger.kernel.org, linux-riscv@lists.infradead.org, linux-snps-arc@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 4/14/21 10:52 AM, Christophe Leroy wrote: > > > Le 14/04/2021 à 04:54, Anshuman Khandual a écrit : >> Currently most platforms define FIRST_USER_ADDRESS as 0UL duplicating the >> same code all over. Instead define a new option ARCH_HAS_FIRST_USER_ADDRESS >> for those platforms which would override generic default FIRST_USER_ADDRESS >> value 0UL. This makes it much cleaner with reduced code. >> >> Cc: linux-alpha@vger.kernel.org >> Cc: linux-snps-arc@lists.infradead.org >> Cc: linux-arm-kernel@lists.infradead.org >> Cc: linux-csky@vger.kernel.org >> Cc: linux-hexagon@vger.kernel.org >> Cc: linux-ia64@vger.kernel.org >> Cc: linux-m68k@lists.linux-m68k.org >> Cc: linux-mips@vger.kernel.org >> Cc: openrisc@lists.librecores.org >> Cc: linux-parisc@vger.kernel.org >> Cc: linuxppc-dev@lists.ozlabs.org >> Cc: linux-riscv@lists.infradead.org >> Cc: linux-s390@vger.kernel.org >> Cc: linux-sh@vger.kernel.org >> Cc: sparclinux@vger.kernel.org >> Cc: linux-um@lists.infradead.org >> Cc: linux-xtensa@linux-xtensa.org >> Cc: x86@kernel.org >> Cc: linux-mm@kvack.org >> Cc: linux-kernel@vger.kernel.org >> Signed-off-by: Anshuman Khandual >> --- >> arch/alpha/include/asm/pgtable.h | 1 - >> arch/arc/include/asm/pgtable.h | 6 ------ >> arch/arm/Kconfig | 1 + >> arch/arm64/include/asm/pgtable.h | 2 -- >> arch/csky/include/asm/pgtable.h | 1 - >> arch/hexagon/include/asm/pgtable.h | 3 --- >> arch/ia64/include/asm/pgtable.h | 1 - >> arch/m68k/include/asm/pgtable_mm.h | 1 - >> arch/microblaze/include/asm/pgtable.h | 2 -- >> arch/mips/include/asm/pgtable-32.h | 1 - >> arch/mips/include/asm/pgtable-64.h | 1 - >> arch/nds32/Kconfig | 1 + >> arch/nios2/include/asm/pgtable.h | 2 -- >> arch/openrisc/include/asm/pgtable.h | 1 - >> arch/parisc/include/asm/pgtable.h | 2 -- >> arch/powerpc/include/asm/book3s/pgtable.h | 1 - >> arch/powerpc/include/asm/nohash/32/pgtable.h | 1 - >> arch/powerpc/include/asm/nohash/64/pgtable.h | 2 -- >> arch/riscv/include/asm/pgtable.h | 2 -- >> arch/s390/include/asm/pgtable.h | 2 -- >> arch/sh/include/asm/pgtable.h | 2 -- >> arch/sparc/include/asm/pgtable_32.h | 1 - >> arch/sparc/include/asm/pgtable_64.h | 3 --- >> arch/um/include/asm/pgtable-2level.h | 1 - >> arch/um/include/asm/pgtable-3level.h | 1 - >> arch/x86/include/asm/pgtable_types.h | 2 -- >> arch/xtensa/include/asm/pgtable.h | 1 - >> include/linux/mm.h | 4 ++++ >> mm/Kconfig | 4 ++++ >> 29 files changed, 10 insertions(+), 43 deletions(-) >> >> diff --git a/include/linux/mm.h b/include/linux/mm.h >> index 8ba434287387..47098ccd715e 100644 >> --- a/include/linux/mm.h >> +++ b/include/linux/mm.h >> @@ -46,6 +46,10 @@ extern int sysctl_page_lock_unfairness; >> void init_mm_internals(void); >> +#ifndef ARCH_HAS_FIRST_USER_ADDRESS > > I guess you didn't test it ..... :) In fact I did :) Though just booted it on arm64 and cross compiled on multiple others platforms. > > should be #ifndef CONFIG_ARCH_HAS_FIRST_USER_ADDRESS Right, meant that instead. > >> +#define FIRST_USER_ADDRESS 0UL >> +#endif > > But why do we need a config option at all for that ? > > Why not just: > > #ifndef FIRST_USER_ADDRESS > #define FIRST_USER_ADDRESS 0UL > #endif This sounds simpler. But just wondering, would not there be any possibility of build problems due to compilation sequence between arch and generic code ?