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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 365A8C433DF for ; Tue, 30 Jun 2020 08:15:21 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 91E472063A for ; Tue, 30 Jun 2020 08:15:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BXvz/3eW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 91E472063A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 49wxxL3lWXzDqkW for ; Tue, 30 Jun 2020 18:15:18 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 49wxvK4kG0zDqgl for ; Tue, 30 Jun 2020 18:13:33 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=BXvz/3eW; dkim-atps=neutral Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) by bilbo.ozlabs.org (Postfix) with ESMTP id 49wxvK0Zg1z8tWK for ; Tue, 30 Jun 2020 18:13:33 +1000 (AEST) Received: by ozlabs.org (Postfix) id 49wxvK0LFNz9sRN; Tue, 30 Jun 2020 18:13:33 +1000 (AEST) Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=redhat.com (client-ip=205.139.110.120; helo=us-smtp-1.mimecast.com; envelope-from=piliu@redhat.com; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=BXvz/3eW; dkim-atps=neutral Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 49wxvJ3WFFz9sR4 for ; Tue, 30 Jun 2020 18:13:29 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593504805; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HTOMqbVijE1+7ERZjjkGYdaILglmW0FhOih0WPQ8e80=; b=BXvz/3eWoVLFAUlxK/4+/YEANc72Wv8V9RRPWkKuXPLIYi4c1DORJ65AtgCZRO6uRgDYt2 a0q6gbSXjLVctAJ3goMfY4pU3+vw4mRCa9gMmkZum14DwNzPYB9qI1NrgA0dULvD+/10u5 cXzyiJC20C3tNSKordwZoUw/S12yZD4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-452-loft5Z2bOUSG5zxBFP8RYQ-1; Tue, 30 Jun 2020 04:13:17 -0400 X-MC-Unique: loft5Z2bOUSG5zxBFP8RYQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C44311883623; Tue, 30 Jun 2020 08:13:15 +0000 (UTC) Received: from [10.72.8.19] (ovpn-8-19.pek2.redhat.com [10.72.8.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7197860BF3; Tue, 30 Jun 2020 08:13:07 +0000 (UTC) Subject: Re: [PATCH 04/11] ppc64/kexec_file: avoid stomping memory used by special regions To: Hari Bathini , Michael Ellerman , Andrew Morton References: <159319825403.16351.7253978047621755765.stgit@hbathini.in.ibm.com> <159319831192.16351.17443438699302756548.stgit@hbathini.in.ibm.com> <9cfda789-0747-a67a-b825-5ea6f15099b8@redhat.com> <283fc181-2331-7c2f-db66-5e02e5ffb2e4@redhat.com> From: piliu Message-ID: Date: Tue, 30 Jun 2020 16:13:04 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 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: Kexec-ml , Petr Tesarik , Mahesh J Salgaonkar , Sourabh Jain , lkml , linuxppc-dev , Mimi Zohar , Thiago Jung Bauermann , Dave Young , Vivek Goyal , Eric Biederman Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 06/30/2020 02:10 PM, Hari Bathini wrote: > > > On 30/06/20 9:00 am, piliu wrote: >> >> >> On 06/29/2020 01:55 PM, Hari Bathini wrote: >>> >>> >>> On 28/06/20 7:44 am, piliu wrote: >>>> Hi Hari, >>> >>> Hi Pingfan, >>> >>>> >>>> After a quick through for this series, I have a few question/comment on >>>> this patch for the time being. Pls see comment inline. >>>> >>>> On 06/27/2020 03:05 AM, Hari Bathini wrote: >>>>> crashkernel region could have an overlap with special memory regions >>>>> like opal, rtas, tce-table & such. These regions are referred to as >>>>> exclude memory ranges. Setup this ranges during image probe in order >>>>> to avoid them while finding the buffer for different kdump segments. >>> >>> [...] >>> >>>>> + /* >>>>> + * Use the locate_mem_hole logic in kexec_add_buffer() for regular >>>>> + * kexec_file_load syscall >>>>> + */ >>>>> + if (kbuf->image->type != KEXEC_TYPE_CRASH) >>>>> + return 0; >>>> Can the ranges overlap [crashk_res.start, crashk_res.end]? Otherwise >>>> there is no requirement for @exclude_ranges. >>> >>> The ranges like rtas, opal are loaded by f/w. They almost always overlap with >>> crashkernel region. So, @exclude_ranges is required to support kdump. >> f/w passes rtas/opal as service, then must f/w mark these ranges as >> fdt_reserved_mem in order to make kernel aware not to use these ranges? > > It does. Actually, reserve_map + reserved-ranges are reserved as soon as > memblock allocator is ready but not before crashkernel reservation. > Check early_reserve_mem() call in kernel/prom.c > >> Otherwise kernel memory allocation besides kdump can also overwrite >> these ranges.> >> Hmm, revisiting reserve_crashkernel(). It seems not to take any reserved >> memory into consider except kernel text. Could it work based on memblock >> allocator? > > So, kdump could possibly overwrite these regions which is why an exclude > range list is needed. Same thing was done in kexec-tools as well. OK, got it. Thanks, Pingfan > > Thanks > Hari > > _______________________________________________ > kexec mailing list > kexec@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/kexec >