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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7BD5EC433F5 for ; Thu, 28 Oct 2021 14:42:56 +0000 (UTC) Received: from phobos.denx.de (phobos.denx.de [85.214.62.61]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C9007600D4 for ; Thu, 28 Oct 2021 14:42:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org C9007600D4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.denx.de Received: from h2850616.stratoserver.net (localhost [IPv6:::1]) by phobos.denx.de (Postfix) with ESMTP id D1E8E834B5; Thu, 28 Oct 2021 16:42:53 +0200 (CEST) Authentication-Results: phobos.denx.de; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=u-boot-bounces@lists.denx.de Received: by phobos.denx.de (Postfix, from userid 109) id CDA9C83513; Thu, 28 Oct 2021 16:42:51 +0200 (CEST) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by phobos.denx.de (Postfix) with ESMTPS id 76523832AF for ; Thu, 28 Oct 2021 16:42:48 +0200 (CEST) Authentication-Results: phobos.denx.de; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=maz@kernel.org Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 50D01600D4; Thu, 28 Oct 2021 14:42:46 +0000 (UTC) Received: from sofa.misterjones.org ([185.219.108.64] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mg6c7-002Eey-Uu; Thu, 28 Oct 2021 15:42:44 +0100 Date: Thu, 28 Oct 2021 15:42:43 +0100 Message-ID: <87tuh19png.wl-maz@kernel.org> From: Marc Zyngier To: Michael Walle Cc: Bharat Gooty , U-Boot Mailing List , Vladimir Oltean , Hou Zhiqiang , Rayagonda Kokatanur , Simon Glass , Priyanka Jain , Tom Rini , Roman Bacik Subject: Re: [PATCH 0/2] arch: arm: gic-v3-its: stop abusing the device tree In-Reply-To: <15b7dc28e0226621fe8c746afe321832@walle.cc> References: <20211027165454.1501398-1-michael@walle.cc> <871r45bk0h.wl-maz@kernel.org> <15b7dc28e0226621fe8c746afe321832@walle.cc> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: michael@walle.cc, bharat.gooty@broadcom.com, u-boot@lists.denx.de, vladimir.oltean@nxp.com, Zhiqiang.Hou@nxp.com, rayagonda.kokatanur@broadcom.com, sjg@chromium.org, priyanka.jain@nxp.com, trini@konsulko.com, roman.bacik@broadcom.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.34 Precedence: list List-Id: U-Boot discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: u-boot-bounces@lists.denx.de Sender: "U-Boot" X-Virus-Scanned: clamav-milter 0.103.2 at phobos.denx.de X-Virus-Status: Clean On Thu, 28 Oct 2021 12:21:59 +0100, Michael Walle wrote: > > Am 2021-10-28 11:20, schrieb Bharat Gooty: > > On Thu, Oct 28, 2021 at 2:33 PM Marc Zyngier wrote: > > > For GIC V3, once the LPI tables are programmed, we can not update it, > > unless we do a reset. > > For the kexec kernel, where the reboot does not happen, in this case, > > during the new kernel boot, the new LPI tables address will not be > > updated. > > kexec.. this should have really gone into both the commit message _and_ > the kconfig menu. In fact, it is really just a workaround for the kexec > case. If I understand it correctly, the kernel is able to communicate > the reserved memory area, but only if you have EFI support. So, as a > workaround, the bootloader can pre-allocate the memory and put it in > the device tree, which is then passed from the old to the new kernel > and the reservation is preserved. Correct, Marc? See my reply to Bharat. Either you use EFI, or you reserve the memory and program the RDs. In either of these two cases, kexec will just work. > But all of this doesn't need any new device tree node. Exactly. The whole syscon stuff is a point hack that makes no sense, and which isn't parsed by any upstream SW. M. -- Without deviation from the norm, progress is not possible.