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 05806C87FD3 for ; Fri, 1 Aug 2025 03:04:56 +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=NlRwIOX39loAW8Ndc7IEtOq9p1vayc9rGBUA9qXU/0w=; b=yE5NVRIjQFQG6QfsRltGea8/Ia Fe+YQYu/8yWzrEH5jFJxskPkmHiQ5HHRQhECTukXU+Scu6/g0WFvWiSGaYcoU3uuUxOTTk04VSICj XzlICKQAS/32xz7IEIDQxRhdRru1jld8vmw25H0leMGq18L03rddznymh2gmqD7usXG3DM/pQzmXl f3qUW25juOnnhS/Miq7IwjFD8iRuWTa64EftLtp7if6zFR3mP+8VtdIiTUE5fJZ3Q3y7wJQe13Mdy 4lW3YpYthiNMBGTU4NMQRmvBOGuKA2w9vlAPQrK9i+iTgaMDN7Z4qtot0jVviC3E7INsco8BYZnXh ahcK10sQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uhg4l-00000004rqi-3SHF; Fri, 01 Aug 2025 03:04:55 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uhg2j-00000004rgj-1UYN for kexec@lists.infradead.org; Fri, 01 Aug 2025 03:02:50 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1754017367; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=NlRwIOX39loAW8Ndc7IEtOq9p1vayc9rGBUA9qXU/0w=; b=A9OCCutWPwHVe3siO/1Tuw5qvk/g0FSlCmPq2X30fehKuoAZEXUn3ftW8Lm2X0rHAE7rT7 sZBoxrktifQsyL8jUYr9UIl3s4InhGEsZNcXAR2P/2ViglyBDygq5SdpX0KfER4BpoUoYU l1oylce4utWuN4r0y7HkcN0xhgwaswE= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-644-ATep_vWVM4mb-Cfc0HRovQ-1; Thu, 31 Jul 2025 23:02:42 -0400 X-MC-Unique: ATep_vWVM4mb-Cfc0HRovQ-1 X-Mimecast-MFC-AGG-ID: ATep_vWVM4mb-Cfc0HRovQ_1754017360 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1D9DA1800374; Fri, 1 Aug 2025 03:02:40 +0000 (UTC) Received: from localhost (unknown [10.72.112.183]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AD09D3000199; Fri, 1 Aug 2025 03:02:36 +0000 (UTC) Date: Fri, 1 Aug 2025 11:02:32 +0800 From: Baoquan He To: Brian Mak Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Andrew Morton , Rob Herring , Saravana Kannan , x86@kernel.org, kexec@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RESEND] x86/kexec: Carry forward the boot DTB on kexec Message-ID: References: <20250729182142.4875-1-makb@juniper.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250729182142.4875-1-makb@juniper.net> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250731_200249_469092_85CA966A X-CRM114-Status: GOOD ( 13.19 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On 07/29/25 at 11:21am, Brian Mak wrote: > The kexec_file_load syscall on x86 currently does not support passing > a device tree blob to the new kernel. > > To add support for this, we copy the behavior of ARM64 and PowerPC and > copy the current boot's device tree blob for use in the new kernel. We > do this on x86 by passing the device tree blob as a setup_data entry in > accordance with the x86 boot protocol. I see how, but no why. Why do we need to add DTB for x86?