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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 11870C46467 for ; Sat, 7 Jan 2023 16:26:59 +0000 (UTC) Received: from h2850616.stratoserver.net (localhost [IPv6:::1]) by phobos.denx.de (Postfix) with ESMTP id 291CB854D4; Sat, 7 Jan 2023 17:26:57 +0100 (CET) Authentication-Results: phobos.denx.de; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=u-boot-bounces@lists.denx.de Authentication-Results: phobos.denx.de; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="QyIKTFMF"; dkim-atps=neutral Received: by phobos.denx.de (Postfix, from userid 109) id AAB42854D4; Sat, 7 Jan 2023 17:26:54 +0100 (CET) Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) (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 DDE6C85254 for ; Sat, 7 Jan 2023 17:26:50 +0100 (CET) Authentication-Results: phobos.denx.de; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=pali@kernel.org Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3B64660AED; Sat, 7 Jan 2023 16:26:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 45253C433EF; Sat, 7 Jan 2023 16:26:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1673108808; bh=Z8LrPAsdi7p38E7tz9fEoul9+9+JjjfO9ZDNdL8FP4U=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QyIKTFMFA+CmiJLz+e6DPY1TfaJcGqQByn01uGC598hdNzoBhSbI+qWj7WftWceFZ UDJE3J77f2fawCtKXVqZTsMtpNkbKKoj/k/CoDQdrYhFrSz6MtSdEw79JcRwCvxD9W ZSdPMJoKEwlqwsizDKtqEeF7GW8VgHNrh5PhEPSsH/PzLkw5Eoye8+E8RNWxUL15me kstnDe4F6OGHXKNsUuRa6N8Id024aG6c/sh4na6StJhTl9v4Axt8ySHYB3tj5vu1bQ mUJhE6mQk1TJ7Hl/pIWCcBPZPIUAeR9KhXYyhg1AFgNMjF0PZNWhzCVuHN8RFcmBzv Vmj6fYSTykY8Q== Received: by pali.im (Postfix) id 33B1AADB; Sat, 7 Jan 2023 17:26:45 +0100 (CET) Date: Sat, 7 Jan 2023 17:26:45 +0100 From: Pali =?utf-8?B?Um9ow6Fy?= To: Tom Rini Cc: u-boot@lists.denx.de, Marek Vasut , Patrick Delaunay Subject: Re: [PATCH] Revert "common/memsize.c: Fix get_effective_memsize() to check for overflow" Message-ID: <20230107162645.2ygz5rk2tlzmiogw@pali> References: <20230106155143.4025812-1-trini@konsulko.com> <20230106164543.3gtq73flpoocg7mc@pali> <20230106172524.GE3787616@bill-the-cat> <20230106202256.bvjwcfsjbhzsfgrh@pali> <20230106211408.GH3787616@bill-the-cat> <20230106214541.GI3787616@bill-the-cat> <20230106220930.pmdjzmdwyx53ouwv@pali> <20230106225156.GJ3787616@bill-the-cat> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230106225156.GJ3787616@bill-the-cat> User-Agent: NeoMutt/20180716 X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.39 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 0.103.6 at phobos.denx.de X-Virus-Status: Clean On Friday 06 January 2023 17:51:56 Tom Rini wrote: > On Fri, Jan 06, 2023 at 11:09:30PM +0100, Pali Rohár wrote: > > On Friday 06 January 2023 16:45:41 Tom Rini wrote: > > > On Fri, Jan 06, 2023 at 04:14:08PM -0500, Tom Rini wrote: > > > > On Fri, Jan 06, 2023 at 09:22:56PM +0100, Pali Rohár wrote: > > > > > On Friday 06 January 2023 12:25:24 Tom Rini wrote: > > > > > > On Fri, Jan 06, 2023 at 05:45:43PM +0100, Pali Rohár wrote: > > > > > > > On Friday 06 January 2023 10:51:43 Tom Rini wrote: > > > > > > > > This reverts commit 777aaaa706bcfe08c284aed06886db7d482af3f8. > > > > > > > > > > > > > > > > The changes to this generic function, which is intended to help with > > > > > > > > 32bit platforms with large amounts of memory has unintended side effects > > > > > > > > (which in turn lead to boot failures) on other platforms which were > > > > > > > > previously functional. > > > > > > > > > > > > > > As mentioned previously, unfortunately this revert breaks 32-bit u-boot > > > > > > > on 36-bit mpc85xx boards with 32-bit e500v2 cores and 4GB DDR module. > > > > > > > > > > > > > > Which platforms currently have broken u-boot without this revert? The > > > > > > > only one which was reported is stm32mp but for it there different > > > > > > > workaround patch waiting in the queue. > > > > > > > > > > > > Are you able to test on one of these PowerPC platforms currently? As > > > > > > the stm32 problem shows, not everything is getting tested frequently > > > > > > enough, so how many other cases are lurking out there. And, I think > > > > > > overall issue is that the overflow check-and-change you introduce here > > > > > > should just be in the CONFIG_MAX_MEM_MAPPED==true case. As that's the > > > > > > case you're dealing with, yes? > > > > > > > > > > I was planning to do big retest again after all powerpc patches are > > > > > reviewed and merged... > > > > > > > > Yes, but can you test one of them now, to see if my idea works? > > > > Ok, I will try to look at during the weekend. > > OK, good, thanks. > > > > > > Anyway, if the issue here is with ram_size and its reduction was needed > > > > > for mpc85xx (at the time of introduction of that patch), what about > > > > > putting mpc85xx ifdef around ram_size reduction? For arm boards it would > > > > > have same behavior as revert of that commit and for mpc85xx it would be > > > > > no change. > > > > This is what I mean: > > > > #ifdef CONFIG_MPC85xx > > if (gd->ram_base + ram_size < gd->ram_base) > > ram_size = ...; > > #endif > > > > > > > I agree that this code needs to be revisited, together with ram_top > > > > > issue and also code which fills DDR banks. Because really mapped memory > > > > > for u-boot and real size of DDR are two different things here. > > > > > > > > The issue here is that we see two now (given Fabio's reminder about > > > > another thread I had forgotten) of unintended consequences, on 32bit > > > > platforms trying to normally have 2GB of memory, which does not require > > > > special treatment. > > > > Running git grep get_effective_memsize and git grep 'gd->ram_top' shows > > the root of this issue: Different platforms, boards and common code use > > these things differently. This needs to be "fixed" = unified in whole > > codebase. We need a function which returns mappable memory for u-boot > > (intptr_t type is enough) and another function (or structure or > > whatever) which says total size of RAM as u64 type (to ensure that it > > would work also for 4GB SODIMM modules on pure 32-bit platforms). And > > then each place in u-boot code has to be modified to use the correct > > function. > > > > Second issue is then gd->ram_top. Either say 4GB for 32-bit ram_top type > > is not supported or say that zero value is special and represents 4GB. > > And also every place in u-boot code needs to be adjusted by this > > decision / code. > > > > Fixing both issues make easily break lot of boards (if done improperly) > > as it touches whole u-boot code base. So not easy task. > > > > > What I'm leaning towards right now even, is that since it's hard to test > > > the non-36bit platforms that do set CONFIG_MAX_MEM_MAPPED, to see if > > > their behavior also changed here, the 36bit platforms should just be > > > overriding get_effective_memsize. > > > > There are (at least) 3 situation: > > 1) if RAM is mapped to the end of physical address space (possibly just > > small e.g. 1GB) > > 2) if platform is >32-bit but running in 32-bit mode (so physical > > address is u64 because we do not have e.g. int36_t; but void* is > > 32-bit) > > 3) if RAM is exactly 4GB and u-boot is 32-bit > > > > And every one has different edge cases and cause different problems. > > Now, as I pointed above that every platform / board is using > > get_effective_memsize() differently, plus we have CONFIG_MAX_MEM_MAPPED > > option, it means that number of test matrix is really huge. > > > > It looks like that ARM issues are caused by the fact that RAM is mapped > > to the end of the physical address space (so it does not matter how big > > or small it is). And powerpc issue is 4GB of RAM together with running > > in 32-bit mode. > > > > Anyway, has U-Boot support for 32-bit x86 CPUs with PAE support? If yes, > > then I bet that there can be other edge cases when e.g. 8GB of DDR is > > connected. > > Yes, it's very much a mess, so for this release I'd like to return to > either: > - Status quo of v2022.10 (revert this patch) > - Change only CONFIG_MAX_MEM_MAPPED being set behavior (should keep > PowerPC 36bit working, may have unexpected impact on other platforms, > still, but very few at least). Yea, it is a mess. I'm looking at the CONFIG_MAX_MEM_MAPPED again and it is for different situation. CONFIG_MAX_MEM_MAPPED says maximal mapped memory. For mpc85xx it is by default set to 2GB for a very long time. And if base physical address od the RAM is at 2GB or higher then it also hits this 4GB limit. So CONFIG_MAX_MEM_MAPPED does not help there...