From patchwork Thu Apr 6 22:02:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Jiahao X-Patchwork-Id: 13203387 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 98B5DC77B70 for ; Thu, 6 Apr 2023 14:06:05 +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=9xeOK8bxUSbxNsT+7730CRsZ7smiqrKhuSmM+NIw1Dc=; b=XJBaAKyLsNF6sJ i+jwEE2ZMST1qjJxXL9pYXrM6Z+iXNFfdjqSrV1kn7FkJf+1jKY/P1DRIYKPIXRPrmF8i+6ySMFZt wmkQ2Ar16wjVHW1Q2up8wwWCSlLoMhum79HSP6Lwp/AZ64qN9KG1h3V82/tfiW4ZMvjIepfiZIoDw vjs/AlJPz7ye2rt8ayiRGm5c8MC1oJI+7skYB3zDxbzhhOdjPpP/ZOUJuIL2CYEe1qs6IR4tt0TS2 gzyn6WEBwdOScQBGWxkImRdUt9+ZDDJ8cDx65rH0ihb2rNrfV4sDdtjERohNExT91frypLKmg30H1 H1OXjeTHSnfpPS05nfIw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pkQFT-007W3P-1O; Thu, 06 Apr 2023 14:05:59 +0000 Received: from szxga01-in.huawei.com ([45.249.212.187]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pkQFO-007W1A-2T; Thu, 06 Apr 2023 14:05:57 +0000 Received: from dggpemm500016.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Psjt61DPRzrXfC; Thu, 6 Apr 2023 22:04:30 +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, 6 Apr 2023 22:05:47 +0800 From: Chen Jiahao To: , , , CC: , , , , , , , , , , , Subject: [PATCH -next v3 0/2] support allocating crashkernel above 4G explicitly on riscv Date: Fri, 7 Apr 2023 06:02:04 +0800 Message-ID: <20230406220206.3067006-1-chenjiahao16@huawei.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 X-Originating-IP: [10.67.174.205] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) 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-20230406_070555_201701_0ECCFF9B X-CRM114-Status: UNSURE ( 8.60 ) 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 11) crashkernel=1G@0xe0000000 //high=0M, low=0M, no enough low memory, failed 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 | 74 +++++++++++++++++-- 3 files changed, 82 insertions(+), 12 deletions(-)