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=-8.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 B01BCC4727E for ; Mon, 21 Sep 2020 21:53:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6A99C23A60 for ; Mon, 21 Sep 2020 21:53:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728358AbgIUVxK (ORCPT ); Mon, 21 Sep 2020 17:53:10 -0400 Received: from elvis.franken.de ([193.175.24.41]:49923 "EHLO elvis.franken.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726574AbgIUVxK (ORCPT ); Mon, 21 Sep 2020 17:53:10 -0400 Received: from uucp (helo=alpha) by elvis.franken.de with local-bsmtp (Exim 3.36 #1) id 1kKSuS-0001Rx-0B; Mon, 21 Sep 2020 22:59:40 +0200 Received: by alpha.franken.de (Postfix, from userid 1000) id A0D27C0FE4; Mon, 21 Sep 2020 22:41:03 +0200 (CEST) Date: Mon, 21 Sep 2020 22:41:03 +0200 From: Thomas Bogendoerfer To: Youling Tang Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] MIPS: kexec: Add crashkernel=YM handling Message-ID: <20200921204103.GK29322@alpha.franken.de> References: <1600480546-10448-1-git-send-email-tangyouling@loongson.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1600480546-10448-1-git-send-email-tangyouling@loongson.cn> User-Agent: Mutt/1.5.23 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Sep 19, 2020 at 09:55:46AM +0800, Youling Tang wrote: > When the kernel crashkernel parameter is specified with just a size, > we are supposed to allocate a region from RAM to store the crashkernel. > However, MIPS merely reserves physical address zero with no checking > that there is even RAM there. > > Fix this by lifting similar code from x86, importing it to MIPS with the > MIPS specific parameters added. In the absence of any platform specific > information, we allocate the crashkernel region from the first 512MB of > physical memory (limited to CKSEG0 or KSEG0 address range). > > When X is not specified, crash_base defaults to 0 (crashkernel=YM@XM). > > E.g. without this patch: > > The environment as follows: > [ 0.000000] MIPS: machine is loongson,loongson64c-4core-ls7a > ... > [ 0.000000] Kernel command line: root=/dev/sda2 crashkernel=96M ... > > The warning as follows: > [ 0.000000] Invalid memory region reserved for crash kernel > > And the iomem as follows: > 00200000-0effffff : System RAM > 00200000-00b47f87 : Kernel code > 00b47f88-00dfffff : Kernel data > 00e60000-01f73c7f : Kernel bss > 1a000000-1bffffff : pci@1a000000 > ... > > With this patch: > > After increasing crash_base <= 0 handling. > > And the iomem as follows: > 00200000-0effffff : System RAM > 00200000-00b47f87 : Kernel code > 00b47f88-00dfffff : Kernel data > 00e60000-01f73c7f : Kernel bss > 04000000-09ffffff : Crash kernel > 1a000000-1bffffff : pci@1a000000 > ... > > Signed-off-by: Youling Tang > --- > arch/mips/kernel/setup.c | 24 +++++++++++++++++++++--- > 1 file changed, 21 insertions(+), 3 deletions(-) applied to mips-next. Thomas. -- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea. [ RFC1925, 2.3 ]