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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 46B07C55ABD for ; Fri, 13 Nov 2020 03:49:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E3E7C2085B for ; Fri, 13 Nov 2020 03:49:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726194AbgKMDtb (ORCPT ); Thu, 12 Nov 2020 22:49:31 -0500 Received: from [157.25.102.26] ([157.25.102.26]:60464 "EHLO orcam.me.uk" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726011AbgKMDt3 (ORCPT ); Thu, 12 Nov 2020 22:49:29 -0500 Received: from bugs.linux-mips.org (eddie.linux-mips.org [IPv6:2a01:4f8:201:92aa::3]) by orcam.me.uk (Postfix) with ESMTPS id F0B9C2BE0EC; Fri, 13 Nov 2020 03:49:26 +0000 (GMT) Date: Fri, 13 Nov 2020 03:49:25 +0000 (GMT) From: "Maciej W. Rozycki" To: Jinyang He cc: Jiaxun Yang , Serge Semin , Alexander Sverdlin , Thomas Bogendoerfer , linux-mips@vger.kernel.org, Paul Burton , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] MIPS: reserve the memblock right after the kernel In-Reply-To: <4a73a75f-a3b2-7ba1-d8a1-a46f5c20e734@loongson.cn> Message-ID: References: <20201106141001.57637-1-alexander.sverdlin@nokia.com> <20201107094028.GA4918@alpha.franken.de> <1d6a424e-944e-7f21-1f30-989fb61018a8@nokia.com> <20201110095503.GA10357@alpha.franken.de> <20201111145240.lok3q5g3pgcvknqr@mobilestation> <4625868b-f845-2f03-c3f2-fc3ff1ccf63d@flygoat.com> <4a73a75f-a3b2-7ba1-d8a1-a46f5c20e734@loongson.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 13 Nov 2020, Jinyang He wrote: > Commit: d3ff93380232 (mips: Make sure kernel memory is in iomem) > As I thought, this check is related to kdump. More directly, it is > related to the "mem=" parameter. Kexec-tools provide a "mem=" parameter > to limit the kernel location in kdump. But sometimes the memory may be not > enough and this check gives a way to ensure the capture kernel can > start rightly. Although "mem=" is not in kexec-tools now, I thought > it is also useful if someone use "mem=" to do other things. I used to supply `mem=' by hand on many occasions across different MIPS systems and for various reasons over the last 20 years; surely before kexec was even thought of. The option itself has been there in the MIPS port since I added it to Linux 2.4.0 back in Dec 2000. Maciej