From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D6D7DC4332F for ; Tue, 28 Dec 2021 13:29:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233491AbhL1N3q (ORCPT ); Tue, 28 Dec 2021 08:29:46 -0500 Received: from szxga02-in.huawei.com ([45.249.212.188]:29305 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233387AbhL1N3K (ORCPT ); Tue, 28 Dec 2021 08:29:10 -0500 Received: from dggpemm500023.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4JNb2w0S3jzbjlD; Tue, 28 Dec 2021 21:28:40 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggpemm500023.china.huawei.com (7.185.36.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Tue, 28 Dec 2021 21:29:08 +0800 Received: from thunder-town.china.huawei.com (10.174.178.55) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Tue, 28 Dec 2021 21:29:07 +0800 From: Zhen Lei To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , , "H . Peter Anvin" , , Dave Young , Baoquan He , Vivek Goyal , Eric Biederman , , Catalin Marinas , "Will Deacon" , , Rob Herring , Frank Rowand , , Jonathan Corbet , CC: Zhen Lei , Randy Dunlap , Feng Zhou , Kefeng Wang , Chen Zhou , "John Donnelly" Subject: [PATCH v19 13/13] kdump: update Documentation about crashkernel Date: Tue, 28 Dec 2021 21:26:12 +0800 Message-ID: <20211228132612.1860-14-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.26.0.windows.1 In-Reply-To: <20211228132612.1860-1-thunder.leizhen@huawei.com> References: <20211228132612.1860-1-thunder.leizhen@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org From: Chen Zhou For arm64, the behavior of crashkernel=X has been changed, which tries low allocation in DMA zone and fall back to high allocation if it fails. We can also use "crashkernel=X,high" to select a high region above DMA zone, which also tries to allocate at least 256M low memory in DMA zone automatically and "crashkernel=Y,low" can be used to allocate specified size low memory. So update the Documentation. Signed-off-by: Chen Zhou Signed-off-by: Zhen Lei --- Documentation/admin-guide/kdump/kdump.rst | 11 +++++++++-- Documentation/admin-guide/kernel-parameters.txt | 11 +++++++++-- 2 files changed, 18 insertions(+), 4 deletions(-) diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst index cb30ca3df27c9b2..d4c287044be0c70 100644 --- a/Documentation/admin-guide/kdump/kdump.rst +++ b/Documentation/admin-guide/kdump/kdump.rst @@ -361,8 +361,15 @@ Boot into System Kernel kernel will automatically locate the crash kernel image within the first 512MB of RAM if X is not given. - On arm64, use "crashkernel=Y[@X]". Note that the start address of - the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000). + On arm64, use "crashkernel=X" to try low allocation in DMA zone and + fall back to high allocation if it fails. + We can also use "crashkernel=X,high" to select a high region above + DMA zone, which also tries to allocate at least 256M low memory in + DMA zone automatically. + "crashkernel=Y,low" can be used to allocate specified size low memory. + Use "crashkernel=Y@X" if you really have to reserve memory from + specified start address X. Note that the start address of the kernel, + X if explicitly specified, must be aligned to 2MiB (0x200000). Load the Dump-capture Kernel ============================ diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index fc34332c8d9a6df..5fafeea70f8f14d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -783,6 +783,9 @@ [KNL, X86-64] Select a region under 4G first, and fall back to reserve region above 4G when '@offset' hasn't been specified. + [KNL, ARM64] Try low allocation in DMA zone and fall back + to high allocation if it fails when '@offset' hasn't been + specified. See Documentation/admin-guide/kdump/kdump.rst for further details. crashkernel=range1:size1[,range2:size2,...][@offset] @@ -799,6 +802,8 @@ Otherwise memory region will be allocated below 4G, if available. It will be ignored if crashkernel=X is specified. + [KNL, ARM64] range in high memory. + Allow kernel to allocate physical memory region from top. crashkernel=size[KMG],low [KNL, X86-64] range under 4G. When crashkernel=X,high is passed, kernel could allocate physical memory region @@ -807,13 +812,15 @@ requires at least 64M+32K low memory, also enough extra low memory is needed to make sure DMA buffers for 32-bit devices won't run out. Kernel would try to allocate at - at least 256M below 4G automatically. + least 256M below 4G automatically. This one let user to specify own low range under 4G for second kernel instead. 0: to disable low allocation. It will be ignored when crashkernel=X,high is not used or memory reserved is below 4G. - + [KNL, ARM64] range in low memory. + This one let user to specify a low range in DMA zone for + crash dump kernel. cryptomgr.notests [KNL] Disable crypto self-tests -- 2.25.1