From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from avon.wwwdotorg.org ([70.85.31.133]:60555 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757021Ab2CGU14 (ORCPT ); Wed, 7 Mar 2012 15:27:56 -0500 Message-ID: <4F57C4C6.2070602@wwwdotorg.org> Date: Wed, 07 Mar 2012 13:27:50 -0700 From: Stephen Warren MIME-Version: 1.0 Subject: Re: [PATCH 2/3] Kbuild: Implement CONFIG_UIMAGE_KERNEL_NOLOAD References: <1331080238-1524-1-git-send-email-swarren@wwwdotorg.org> <1331080238-1524-2-git-send-email-swarren@wwwdotorg.org> <20120307180815.GA27213@game.jcrosoft.org> <4F57AB92.6060907@wwwdotorg.org> <20120307183633.GB27213@game.jcrosoft.org> In-Reply-To: <20120307183633.GB27213@game.jcrosoft.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: Jean-Christophe PLAGNIOL-VILLARD Cc: Michal Marek , linux-arch@vger.kernel.org, Michal Simek , Guan Xuetao , Mike Frysinger , nico@fluxnic.net, linux-sh@vger.kernel.org, microblaze-uclinux@itee.uq.edu.au, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, Paul Mundt , uclinux-dist-devel@blackfin.uclinux.org, sparclinux@vger.kernel.org, Russell King , Haavard Skinnemoen , "David S. Miller" , linux-arm-kernel@lists.infradead.org, Hans-Christian Egtvedt On 03/07/2012 11:36 AM, Jean-Christophe PLAGNIOL-VILLARD wrote: > On 11:40 Wed 07 Mar , Stephen Warren wrote: >> On 03/07/2012 11:08 AM, Jean-Christophe PLAGNIOL-VILLARD wrote: >>> On 17:30 Tue 06 Mar , Stephen Warren wrote: >>>> This allows the user to use U-Boot's mkimage's -T kernel_noload option >>>> if their arch Kconfig allows it, and they desire. >>>> >>>> Signed-off-by: Stephen Warren >>>> --- >>>> The next patch enables this new CONFIG_ALLOW_ option for ARM. I assume >>>> that some other architectures will also be able to enable it, but I'm >>>> not familiar enough with any to know which. >>> I'm going to repeat. I don't think any impromevent here. >>> >>> with no specific kernel load address the uImage for is useless/ >> >> No, the whole point of this type of kernel image is that it doesn't need >> a specific load address; the kernel zImage can run from anywhere in RAM >> (provided AUTO_ZRELADDR is enabled, subject to some slight >> restrictions), and hence the uImage doesn't need to be loaded to or >> moved to any particular location. >> >> The scripts that U-Boot runs determine where the image gets loaded into >> memory. > > so instead of spending time on the uImage add simply the support the zImage to > U-Boot as this AUTO_ZRELADDR have 0 advantage compare to the zImage Thinking more about this, I guess the reliance on AUTO_ZRELADDR is wrong here; Russell, Nico, is the ARM decompressor fully position-independent irrespective of the AUTO_ZRELADDR setting. That setting just determines where the decompressor writes its output, not what address the decompressor can run at, right? So, this KERNEL_NOLOAD feature could be enabled in all cases on ARM, not only when AUTO_ZRELADDR is enabled. As such to address Jean-Christophe's most recent comment above, this patch isn't about adding support for AUTO_ZRELADDR, but for U-Boot's kernel_noload feature, so comparisons should be drawn between kernel_noload uImages and zImage, not between AUTO_ZRELADDR and zImage. In other words: We already have and need ZRELADDR no matter what, for reasons unrelated to U-Boot/uImage. Patch 1 in this series is just consolidating duplicate definitions, and doesn't introduce any new features, so I think hope you think it's a good thing no matter what anyone thinks about U-Boot/uImage. I assume you're only arguing about patches 2 and 3?