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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 69CF1C4321E for ; Fri, 7 Sep 2018 09:57:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E7A5204FD for ; Fri, 7 Sep 2018 09:57:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E7A5204FD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728647AbeIGOhY (ORCPT ); Fri, 7 Sep 2018 10:37:24 -0400 Received: from foss.arm.com ([217.140.101.70]:57844 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725942AbeIGOhX (ORCPT ); Fri, 7 Sep 2018 10:37:23 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B3972ED1; Fri, 7 Sep 2018 02:57:13 -0700 (PDT) Received: from [10.4.12.81] (melchizedek.emea.arm.com [10.4.12.81]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A2BD03F614; Fri, 7 Sep 2018 02:57:12 -0700 (PDT) Subject: Re: [RESEND PATCH v4 1/6] arm64/mm: Introduce the init_pg_dir. To: Jun Yao Cc: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org References: <20180822095432.12125-1-yaojun8558363@gmail.com> <20180822095432.12125-2-yaojun8558363@gmail.com> From: James Morse Message-ID: <6e614449-5574-98f6-cc39-f6fbddea48d8@arm.com> Date: Fri, 7 Sep 2018 10:57:11 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180822095432.12125-2-yaojun8558363@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jun, On 22/08/18 10:54, Jun Yao wrote: > To make the swapper_pg_dir read only, we will move it to the rodata > section. And force the kernel to set up the initial page table in > the init_pg_dir. After generating all levels page table, we copy > only the top level into the swapper_pg_dir during paging_init(). Could you add v3's | Add init_pg_dir to vmlinux.lds.S and boiler-plate | clearing/cleaning/invalidating it in head.S. too. This makes it obvious that 'init_pg_dir isn't used yet' is deliberate. Reviewed-by: James Morse Some boring nits: > diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h > index 0bcc98dbba56..eb363a915c0e 100644 > --- a/arch/arm64/include/asm/assembler.h > +++ b/arch/arm64/include/asm/assembler.h > @@ -456,6 +456,35 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU > +/* > + * clear_pages - clear contiguous pages > + * > + * start, end: page aligend virtual addresses (Nit: aligned) > + */ > + .macro clear_pages, start:req, end:req > diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S > index 605d1b60469c..61d7cee3eaa6 100644 > --- a/arch/arm64/kernel/vmlinux.lds.S > +++ b/arch/arm64/kernel/vmlinux.lds.S > @@ -68,6 +68,12 @@ jiffies = jiffies_64; > #define TRAMP_TEXT > #endif > > +#define INIT_PG_TABLES \ ^ These are tabs ... > + . = ALIGN(PAGE_SIZE); \ ^ ... but these are spaces. > + init_pg_dir = .; \ > + . += SWAPPER_DIR_SIZE; \ > + init_pg_end = .; Please pick one and stick with it. The macro above, CONFIG_UNMAP_KERNEL_AT_EL0, uses tabs, please do the same. Thanks, James