From patchwork Mon Mar 20 20:42:42 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Jiahao X-Patchwork-Id: 13181129 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E26E8C76195 for ; Mon, 20 Mar 2023 12:46:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:CC :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=I0lyZLRYW78CeZycTGr8xKKp2Wsx6xl3QFfW9U5/qA0=; b=Dv+Rzuxt6H7Eng UZSeLfXrxeh4y/yIKJ//WmeQh7FP4w6le311RckjhosfNees2n8oWdKxqvjmX20VsAqRvMeoiVZSn Yn/BHT7edv4WZw+e6fM8MoekegnV1ZhZw6cPzsdr2v5LRwrjHxJLFbr08PziC2h4LNEho3SCRKDPF zxq0wJ+CBxnftvSkQpdkKfIRV9fndRSZBGouUfBsqSFlQUWF889UCejWOB/zJHIv8WC36+EctUE8s QjkyUukAiseu84y5j5w0licG9ggWSJ+JGKilvRywo2OpEQVwLWCQY121UW7vVTv7F4tibCt+8f1Hi lPLe8n3ZPfRgz15muJGA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1peEu1-008zq4-1O; Mon, 20 Mar 2023 12:46:17 +0000 Received: from szxga08-in.huawei.com ([45.249.212.255]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1peEtx-008zoP-2l; Mon, 20 Mar 2023 12:46:15 +0000 Received: from dggpemm500016.china.huawei.com (unknown [172.30.72.55]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4PgDss0NYZz17MgP; Mon, 20 Mar 2023 20:42:57 +0800 (CST) Received: from huawei.com (10.67.174.205) by dggpemm500016.china.huawei.com (7.185.36.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Mon, 20 Mar 2023 20:46:00 +0800 From: Chen Jiahao To: , , , , , , , , , , CC: , , , Subject: [PATCH -next 0/2] support allocating crashkernel above 4G explicitly on riscv Date: Tue, 21 Mar 2023 04:42:42 +0800 Message-ID: <20230320204244.1637821-1-chenjiahao16@huawei.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 X-Originating-IP: [10.67.174.205] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500016.china.huawei.com (7.185.36.25) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230320_054614_079838_A5FBAF4F X-CRM114-Status: UNSURE ( 6.50 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On riscv, the current crash kernel allocation logic is trying to allocate within 32bit addressible memory region by default, if failed, try to allocate without 4G restriction. In need of saving DMA zone memory while allocating a relatively large crash kernel region, allocating the reserved memory top down in high memory, without overlapping the DMA zone, is a mature solution. Hence this patchset introduces the parameter option crashkernel=X,[high,low]. One can reserve the crash kernel from high memory above DMA zone range by explicitly passing "crashkernel=X,high"; or reserve a memory range below 4G with "crashkernel=X,low". Besides, there are few rules need to take notice: 1. "crashkernel=X,[high,low]" will be ignored if "crashkernel=size" is specified. 2. "crashkernel=X,low" is valid only when "crashkernel=X,high" is passed and there is enough memory to be allocated under 4G. 3. When allocating crashkernel above 4G and no "crashkernel=X,low" is specified, a 128M low memory will be allocated automatically for swiotlb bounce buffer. See Documentation/admin-guide/kernel-parameters.txt for more information. Following test cases have been performed as expected: 1) crashkernel=256M //low=256M 2) crashkernel=1G //low=1G 3) crashkernel=4G //high=4G, low=128M(default) 4) crashkernel=4G crashkernel=256M,high //high=4G, low=128M(default), high is ignored 5) crashkernel=4G crashkernel=256M,low //high=4G, low=128M(default), low is ignored 6) crashkernel=4G,high //high=4G, low=128M(default) 7) crashkernel=256M,low //low=0M, invalid 8) crashkernel=4G,high crashkernel=256M,low //high=4G, low=256M 9) crashkernel=4G,high crashkernel=4G,low //high=0M, low=0M, invalid 10) crashkernel=512M@0xd0000000 //low=512M Chen Jiahao (2): riscv: kdump: Implement crashkernel=X,[high,low] docs: kdump: Update the crashkernel description for riscv .../admin-guide/kernel-parameters.txt | 15 ++--- arch/riscv/kernel/setup.c | 5 ++ arch/riscv/mm/init.c | 56 ++++++++++++++++++- 3 files changed, 66 insertions(+), 10 deletions(-)