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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 B8F9CC43381 for ; Mon, 1 Apr 2019 15:38:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8BB5120880 for ; Mon, 1 Apr 2019 15:38:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728626AbfDAPiP (ORCPT ); Mon, 1 Apr 2019 11:38:15 -0400 Received: from foss.arm.com ([217.140.101.70]:36818 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726617AbfDAPiO (ORCPT ); Mon, 1 Apr 2019 11:38:14 -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 586FCA78; Mon, 1 Apr 2019 08:38:14 -0700 (PDT) Received: from fuggles.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 01E643F690; Mon, 1 Apr 2019 08:38:12 -0700 (PDT) Date: Mon, 1 Apr 2019 16:38:10 +0100 From: Will Deacon To: pierre kuo Cc: Catalin Marinas , Steven Price , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Florian Fainelli , ard.biesheuvel@linaro.org Subject: Re: [PATCH v2 1/1] initrd: move initrd_start calculate within linear mapping range check Message-ID: <20190401153810.GC6884@fuggles.cambridge.arm.com> References: <20190314032047.15790-1-vichy.kuo@gmail.com> <20190319153114.GI59586@arrakis.emea.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.1+86 (6f28e57d73f2) () Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [+Ard in case I'm missing something] On Mon, Apr 01, 2019 at 10:59:53PM +0800, pierre kuo wrote: > > > With CONFIG_RANDOMIZE_BASE we can get a further change to memstart_addr > > > after the place where you moved the initrd_{start,end} setting, which > > > would result in a different value for __phys_to_virt(phys_initrd_start). > > > > I found what you mean, since __phys_to_virt will use PHYS_OFFSET > > (memstart_addr) for calculating. > > How about moving CONFIG_RANDOMIZE_BASE part of code ahead of > > CONFIG_BLK_DEV_INITRD checking? > > > > That means below (d) moving ahead of (c) > > prvious: > > if (memstart_addr + linear_region_size < memblock_end_of_DRAM()) {} ---(a) > > if (memory_limit != PHYS_ADDR_MAX) {} ---(b) > > if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) {} ---(c) > > if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {} ---(d) > > > > now: > > if (memstart_addr + linear_region_size < memblock_end_of_DRAM()) { ---(a) > > if (memory_limit != PHYS_ADDR_MAX) {} ----------------(b) > > if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {} --------------(d) > > if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) {} ---(c) > > > > After tracing the kernel code, > is it even possible to move CONFIG_RANDOMIZE_BASE part of code ahead > of memory_limit? > > that mean the flow may look like below: > now2: > if (memstart_addr + linear_region_size < memblock_end_of_DRAM()) {} ---(a) > if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {} ---(d) > if (memory_limit != PHYS_ADDR_MAX) {} ---(b) > if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) {} ---(c) > > in (b), the result of __pa_symbol(_text), memory_limit, > memblock_mem_limit_remove_map and memblock_add > are not depended on memsart_addr. > So the now2 flow can grouping modification of memstart_address, put > (a) and (d) together. I'm afraid that you've lost me with this. Why isn't it just as simple as the diff below? Will --->8 diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index c29b17b520cd..ec3487c94b10 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -377,7 +377,7 @@ void __init arm64_memblock_init(void) base + size > memblock_start_of_DRAM() + linear_region_size, "initrd not fully accessible via the linear mapping -- please check your bootloader ...\n")) { - initrd_start = 0; + phys_initrd_size = 0; } else { memblock_remove(base, size); /* clear MEMBLOCK_ flags */ memblock_add(base, size);