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 X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3EDD7C04A6B for ; Thu, 9 May 2019 01:37:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1B562214AF for ; Thu, 9 May 2019 01:37:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726650AbfEIBhH (ORCPT ); Wed, 8 May 2019 21:37:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56720 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725778AbfEIBhF (ORCPT ); Wed, 8 May 2019 21:37:05 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DD19FC045129; Thu, 9 May 2019 01:37:04 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (ovpn-12-17.pek2.redhat.com [10.72.12.17]) by smtp.corp.redhat.com (Postfix) with ESMTP id DCF87451A; Thu, 9 May 2019 01:37:01 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, mingo@kernel.org, bp@alien8.de, hpa@zytor.com, kirill.shutemov@linux.intel.com, x86@kernel.org, dyoung@redhat.com, Baoquan He Subject: [PATCH v4 3/3] x86/kdump/64: Change the upper limit of crashkernel reservation Date: Thu, 9 May 2019 09:36:44 +0800 Message-Id: <20190509013644.1246-4-bhe@redhat.com> In-Reply-To: <20190509013644.1246-1-bhe@redhat.com> References: <20190509013644.1246-1-bhe@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Thu, 09 May 2019 01:37:05 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Restrict kdump to only reserve crashkernel below 64TB. The reaons is that the kdump may jump from 5-level to 4-level, and if the kdump kernel is put above 64TB, then the jumping will fail. While the 1st kernel reserves crashkernel region during bootup, we don't know yet which kind of kernel will be loaded after system bootup, 5-level kernel or 5-level kernel. Signed-off-by: Baoquan He Acked-by: Kirill A. Shutemov --- arch/x86/kernel/setup.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 905dae880563..efb0934a46f6 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -452,15 +452,26 @@ static void __init memblock_x86_reserve_range_setup_data(void) #define CRASH_ALIGN SZ_16M /* - * Keep the crash kernel below this limit. On 32 bits earlier kernels - * would limit the kernel to the low 512 MiB due to mapping restrictions. + * Keep the crash kernel below this limit. + * + * On 32 bits earlier kernels would limit the kernel to the low + * 512 MiB due to mapping restrictions. + * + * On 64bit, old kexec-tools need to be under 896MiB. The later + * supports to put kernel above 4G, up to system RAM top. Here + * kdump kernel need be restricted to be under 64TB, which is + * the upper limit of system RAM in 4-level paing mode. Since + * the kdump jumping could be from 5-level to 4-level, the jumping + * will fail if kernel is put above 64TB, and there's no way to + * detect the paging mode of the kernel which will be loaded for + * dumping during the 1st kernel bootup. */ #ifdef CONFIG_X86_32 # define CRASH_ADDR_LOW_MAX SZ_512M # define CRASH_ADDR_HIGH_MAX SZ_512M #else # define CRASH_ADDR_LOW_MAX SZ_4G -# define CRASH_ADDR_HIGH_MAX MAXMEM +# define CRASH_ADDR_HIGH_MAX (64UL << 40) #endif static int __init reserve_crashkernel_low(void) -- 2.17.2