From patchwork Mon May 7 06:32:24 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baoquan He X-Patchwork-Id: 909547 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 40fXrb3RMCz9s27 for ; Mon, 7 May 2018 16:33:51 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751379AbeEGGds (ORCPT ); Mon, 7 May 2018 02:33:48 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:36900 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751010AbeEGGdp (ORCPT ); Mon, 7 May 2018 02:33:45 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A17C142EF0DA; Mon, 7 May 2018 06:33:44 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (ovpn-8-16.pek2.redhat.com [10.72.8.16]) by smtp.corp.redhat.com (Postfix) with ESMTP id 15073111F3B6; Mon, 7 May 2018 06:33:29 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, robh+dt@kernel.org, dan.j.williams@intel.com, nicolas.pitre@linaro.org, josh@joshtriplett.org, fengguang.wu@intel.com, bp@suse.de Cc: patrik.r.jakobsson@gmail.com, airlied@linux.ie, kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, dmitry.torokhov@gmail.com, frowand.list@gmail.com, keith.busch@intel.com, jonathan.derrick@intel.com, lorenzo.pieralisi@arm.com, bhelgaas@google.com, tglx@linutronix.de, brijesh.singh@amd.com, jglisse@redhat.com, thomas.lendacky@amd.com, gregkh@linuxfoundation.org, baiyaowei@cmss.chinamobile.com, richard.weiyang@gmail.com, devel@linuxdriverproject.org, linux-input@vger.kernel.org, linux-nvdimm@lists.01.org, devicetree@vger.kernel.org, linux-pci@vger.kernel.org, ebiederm@xmission.com, vgoyal@redhat.com, dyoung@redhat.com, yinghai@kernel.org, kexec@lists.infradead.org, monstr@monstr.eu, davem@davemloft.net, chris@zankel.net, jcmvbkbc@gmail.com, gustavo@padovan.org, maarten.lankhorst@linux.intel.com, seanpaul@chromium.org, linux-parisc@vger.kernel.org, Baoquan He Subject: [PATCH v4 3/3] kexec_file: Load kernel at top of system RAM if required Date: Mon, 7 May 2018 14:32:24 +0800 Message-Id: <20180507063224.24229-4-bhe@redhat.com> In-Reply-To: <20180507063224.24229-1-bhe@redhat.com> References: <20180507063224.24229-1-bhe@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Mon, 07 May 2018 06:33:44 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Mon, 07 May 2018 06:33:44 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'bhe@redhat.com' RCPT:'' Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org For kexec_file loading, if kexec_buf.top_down is 'true', the memory which is used to load kernel/initrd/purgatory is supposed to be allocated from top to down. This is what we have been doing all along in the old kexec loading interface and the kexec loading is still default setting in some distributions. However, the current kexec_file loading interface doesn't do likt this. The function arch_kexec_walk_mem() it calls ignores checking kexec_buf.top_down, but calls walk_system_ram_res() directly to go through all resources of System RAM from bottom to up, to try to find memory region which can contain the specific kexec buffer, then call locate_mem_hole_callback() to allocate memory in that found memory region from top to down. This brings confusion especially when KASLR is widely supported , users have to make clear why kexec/kdump kernel loading position is different between these two interfaces in order to exclude unnecessary noises. Hence these two interfaces need be unified on behaviour. Here add checking if kexec_buf.top_down is 'true' in arch_kexec_walk_mem(), if yes, call the newly added walk_system_ram_res_rev() to find memory region from top to down to load kernel. Signed-off-by: Baoquan He Cc: Eric Biederman Cc: Vivek Goyal Cc: Dave Young Cc: Andrew Morton Cc: Yinghai Lu Cc: kexec@lists.infradead.org --- kernel/kexec_file.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 75d8e7cf040e..7a66d9d5a534 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -518,6 +518,8 @@ int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf, IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, crashk_res.start, crashk_res.end, kbuf, func); + else if (kbuf->top_down) + return walk_system_ram_res_rev(0, ULONG_MAX, kbuf, func); else return walk_system_ram_res(0, ULONG_MAX, kbuf, func); }