From patchwork Thu May 11 08:51:37 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Jiahao X-Patchwork-Id: 13237666 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 A17E4C7EE2A for ; Thu, 11 May 2023 08:51:43 +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=S9+vuKPstgyv3HfX3NyPU3O17Olnk5pVPZPHLIWh9pE=; b=rzkem8rc8YYcdB 0ymErEH/vxOqATE8zGXtSDaM5iCJBH3iZJf3IWefbNUM/IaDQExvBVrAjCrdzczFs1m3ZVuk71tdh cC1WlrlxNvUCar3l5o1ByLW2uA4Tlb6YD1ZKtyGDYz7H8ktzB9Lp683LnFUYpac9yqJTgGAedBSs5 m2CB96UYlDG4WiaSmjJSgUMkIuAXC5NPl6jRblbZFXmA9nPDeRnYuMByb4Puz5ZE3V2GSZyHTRFhA wfKGDGK8s7H94XFrW86//XYlhZI3PUWy23e3IfdVspTx7wIQJvB4CEqscv84Jevz/ZW7JkXKoY3zl IO5Im3w9cABX2UpWjwaQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1px21T-008Gjc-0E; Thu, 11 May 2023 08:51:39 +0000 Received: from szxga02-in.huawei.com ([45.249.212.188]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1px21O-008Gi0-2l; Thu, 11 May 2023 08:51:36 +0000 Received: from dggpemm500016.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4QH59S0MtbzTk81; Thu, 11 May 2023 16:46:52 +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 15.1.2507.23; Thu, 11 May 2023 16:51:31 +0800 From: Chen Jiahao To: , , , CC: , , , , , , , , , , , Subject: [PATCH -next v5 0/2] support allocating crashkernel above 4G explicitly on riscv Date: Thu, 11 May 2023 16:51:37 +0800 Message-ID: <20230511085139.1039088-1-chenjiahao16@huawei.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 X-Originating-IP: [10.67.174.205] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) 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-20230511_015135_249336_E668A112 X-CRM114-Status: UNSURE ( 8.63 ) 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. To verify loading the crashkernel, adapted kexec-tools is attached below: https://github.com/chenjh005/kexec-tools/tree/build-test-riscv-v2 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 Changes since [v5]: 1. Update the crashkernel allocation logic when crashkernel=X,high is specified. In this case, region above 4G will directly get reserved as crashkernel, rather than trying lower 32bit allocation first. Changes since [v4]: 1. Update some imprecise code comments for cmdline parsing. Changes since [v3]: 1. Update to print warning and return explicitly on failure when crashkernel=size@offset is specified. Not changing the result in this case but making the logic more straightforward. 2. Some minor cleanup. Changes since [v2]: 1. Update the allocation logic to ensure the high crashkernel region is reserved strictly above dma32_phys_limit. 2. Clean up some minor format problems. 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 | 73 +++++++++++++++++-- 3 files changed, 79 insertions(+), 14 deletions(-)