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 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 52E57CD342C for ; Wed, 6 May 2026 14:45:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=1gQBDn5gKWm7O7hpQ736XvX5gBBMeA1PcVQPRSELa4c=; b=43MDR/M3tHmxaS3tahJ3wIfOIy lljOWPqWDu72ePX37lgr+EJJM/0JSjyCZHhE3fBjURaeLHvYeq3rpkgSpgfjguCN3QmJEiS3RNYJW BbeIqxHReB6gl5J9R8Fm50mgJjeSD9V2FoYeIaDuO3eWAitAskYvxYt2oqR5Ob273QU6m/vAahwzL 66YVkovCFMg6I6MKCI/bYafDgSvnIEsDTMgnt/FSERb4B390rJeS1gC0c+gWQlPwPQYMHdehP0yRQ eWlSae0cPm44rrhzp7WaOkgfS5Xq18enkDBcSLJjQzeP4wJmutSiPjovodImQ5C9fIqXUqKNyYMKM DmBZsmgg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wKdVU-000000018zF-1vVN; Wed, 06 May 2026 14:45:48 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wKdVR-000000018wv-3SpX; Wed, 06 May 2026 14:45:45 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 2A3DF40339; Wed, 6 May 2026 14:45:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C551CC2BCB0; Wed, 6 May 2026 14:45:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778078745; bh=0KO8hApD0eGU7/dmfhl80Uq28cv6QcKZtN0DhSa6VO8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=asJ2zJX1kDJF4N0879YgzX1aEN+OycWFuFs84uFQjFbe8XLl2JHLjmVHMoHBwAk6J EyTzWttjeZ93aH8W7WcFdePxJWrsBw+70Fkp1Sj/wAXvJJ9ZUP0h6gsAQLVvDjqXg+ 1JmbHeC6lmnatopx+tcxUwuh3OWiIVIg9v7sbG4queTxnNERHgV5fuJoHciimhrIva z6tiru0U8Vxnzc3gPBEsx2ByvC9Goicr/7n+uezz8eLpotdhh9lgEl05dnGU8nYkxS OEKJJCfqVKkDK1W7iVncEPYYt+PI8inusarD9Il7nm3cTLeZ9yidzQoX4xCLwhJW5m DVbx5oZerq5OA== Date: Wed, 6 May 2026 09:45:42 -0500 From: Rob Herring To: Chen Wandun Cc: kexec@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, akpm@linux-foundation.org, bhe@redhat.com, rppt@kernel.org, pasha.tatashin@soleen.com, pratyush@kernel.org, ruirui.yang@linux.dev, corbet@lwn.net, skhan@linuxfoundation.org, catalin.marinas@arm.com, will@kernel.org, chenhuacai@kernel.org, kernel@xen0n.name, pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu, saravanak@kernel.org, chenwandun@lixiang.com, zhaomeijing@lixiang.com, everyzhao@126.com Subject: Re: [PATCH 05/11] of: reserved_mem: add linux,no-dump property support for reserved memory regions Message-ID: <20260506144542.GA2072596-robh@kernel.org> References: <20260429065831.1510858-1-chenwandun@lixiang.com> <20260429065831.1510858-6-chenwandun@lixiang.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260429065831.1510858-6-chenwandun@lixiang.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260506_074545_884116_9DFB7232 X-CRM114-Status: GOOD ( 18.01 ) X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Apr 29, 2026 at 02:58:25PM +0800, Chen Wandun wrote: > Add a 'no_dump' field to struct reserved_mem and parse the > 'linux,no-dump' device tree property during reserved memory node > initialization. This property allows device tree authors to mark > specific reserved memory regions that should be excluded from kdump > vmcore dumps. > > Reserved memory regions used by device firmware (e.g., GPU, DSP, modem) > typically contain data that is not useful for kernel crash analysis and > can significantly increase vmcore size. The 'linux,no-dump' property > provides a declarative way to indicate these regions should be filtered > out when constructing the elfcorehdr for kdump. > > The property is named with a 'linux,' prefix because kdump/vmcore is > Linux-specific and the property is an OS hint rather than a hardware > description, matching existing properties such as 'linux,cma-default' > and 'linux,usable-memory-range'. > > The 'linux,no-dump' property is only effective when the region: > - Does not have 'no-map': these regions are already excluded from > vmcore since they are removed from the linear mapping (MEMBLOCK_NOMAP). > - Does not have 'reusable': CMA reusable regions are actively used by > the kernel for movable page allocations, and their contents are > valuable for crash analysis. > > The no-dump status is also printed in the boot log alongside the > existing nomap and reusable flags for diagnostic purposes. I think this property is the wrong way around and probably not needed. The default should be exclude the regions, but if Linux is using the regions (like CMA) then it can decide on its own to include them. With the restructuring that went into 7.1, it should be possible for the CMA code (and code for any other regions) to set some flag for the region. Rob