From patchwork Tue Mar 28 11:51:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Jiahao X-Patchwork-Id: 13190454 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 E4141C761A6 for ; Tue, 28 Mar 2023 03:55:36 +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=inIGvGkjj16KuZvN6A5bWfrlhB5sXUhqELl8CNXc8JI=; b=U+5fGQV70gh+Sf OORE1qLCZIyDhqd+9B4k3iUUBjcDiCsrWuLAdEXaNa9FYqAiG3VnvT7GBA/n/GiBfelRLhogrjkGr 619PDbR38NLXQ4E+v/0v2xdXG6pH2IMYrTQELWMIg5CFp3ZN0XZrsE1r8YeHK9OX5oRbmlHnmGTDR fllZv6uN+f5gAjwszSr/ANWcrVpR+4NDDl8dft0i8c9qNHQEDOcEfuHaHcO3Y93U+IPBhXr8prrkw DaZO27NL3hwOiAPmvSveZ8wWR7CM6whIYjl1HE/u3yF2c9cgpgVnXd27F1NwvYaahimFi+0Ws3SJ5 FlqaG6O9rIr8cRT4C61Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1ph0Qk-00D4MF-2K; Tue, 28 Mar 2023 03:55:30 +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 1ph0Qc-00D4JA-1l; Tue, 28 Mar 2023 03:55:24 +0000 Received: from dggpemm500016.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Plwkc19mWzKvtH; Tue, 28 Mar 2023 11:52:56 +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; Tue, 28 Mar 2023 11:55:18 +0800 From: Chen Jiahao To: , , , , , , , , , , , CC: , , , Subject: [PATCH -next v2 0/2] support allocating crashkernel above 4G explicitly on riscv Date: Tue, 28 Mar 2023 19:51:48 +0800 Message-ID: <20230328115150.2700016-1-chenjiahao16@huawei.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 X-Originating-IP: [10.67.174.205] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) 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-20230327_205522_916952_30B76FA2 X-CRM114-Status: UNSURE ( 7.56 ) 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 [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 | 63 +++++++++++++++++-- 3 files changed, 72 insertions(+), 11 deletions(-)