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 F38E5C433EF for ; Sun, 31 Oct 2021 12:52:10 +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 C4C8C60ED5 for ; Sun, 31 Oct 2021 12:52:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org C4C8C60ED5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=xs4all.nl 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 76B648187B; Sun, 31 Oct 2021 13:52:07 +0100 (CET) Authentication-Results: phobos.denx.de; dmarc=fail (p=none dis=none) header.from=xs4all.nl 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 D6F9A81BF4; Sun, 31 Oct 2021 13:52:04 +0100 (CET) Received: from sibelius.xs4all.nl (sibelius.xs4all.nl [83.163.83.176]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by phobos.denx.de (Postfix) with ESMTPS id F21328020E for ; Sun, 31 Oct 2021 13:51:40 +0100 (CET) Authentication-Results: phobos.denx.de; dmarc=fail (p=none dis=none) header.from=xs4all.nl Authentication-Results: phobos.denx.de; spf=fail smtp.mailfrom=mark.kettenis@xs4all.nl Received: from localhost (bloch.sibelius.xs4all.nl [local]) by bloch.sibelius.xs4all.nl (OpenSMTPD) with ESMTPA id 1a3813e8; Sun, 31 Oct 2021 13:51:16 +0100 (CET) Date: Sun, 31 Oct 2021 13:51:16 +0100 (CET) From: Mark Kettenis To: Michael Walle Cc: u-boot@lists.denx.de In-Reply-To: <1f9f258db11b21bfd7db4fe1eef785eb@walle.cc> (message from Michael Walle on Sun, 31 Oct 2021 13:04:40 +0100) Subject: Re: (overlapping) lmb allocations during boot References: <63a9d684653e3d19e621a8d978f44113@walle.cc> <1f9f258db11b21bfd7db4fe1eef785eb@walle.cc> Message-ID: 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 > Date: Sun, 31 Oct 2021 13:04:40 +0100 > From: Michael Walle > > Am 2021-10-31 12:44, schrieb Mark Kettenis: > >> Date: Sun, 31 Oct 2021 11:43:38 +0100 > >> From: Michael Walle > >> > >> Hi, > >> > >> I sometimes see a corrupted initrd during kernel boot on my board > >> (kontron_sl28). Debugging showed that in this case the spin table > >> for the secondary CPUs overlaps with the lmb initrd allocations > >> (initrd_high is set). > >> > >> I had a look at how the fdt and initrd are relocated (if enabled). In > >> summary, they use lmb_alloc() which will first add all available > >> memory > >> and then carve out reserved regions. There are calls for arch > >> (arch_lmb_reserve()) and board (board_lmb_reserve()) callbacks. The > >> interesting thing is that, there is also code to carve out any > >> reserved regions which were added to the fdt earlier > >> (boot_fdt_add_mem_rsv_regions()). The problem here is, that the DT > >> fixups, > >> which might add the reserved regions are called just before jumping to > >> linux. Thus both the allocation for the fdt (if fdt_high is set) and > >> the ramdisk (if initrd_high is set) will ignore any reserved memory > >> regions. > >> > >> Unfortunately, I don't see any good way to fix this. You'd need all > >> the > >> DT fixups before we can initialize the lmb. Also, I don't know if this > >> will affect any other areas; probably I'm the only one, who reserves > >> an > >> area which is outside of the u-boot code and data segment. > >> > >> A hackish way would be to carve out the spin_table code in > >> board_lmb_reserve(). But meh.. > > > > The spin table is embedded in the u-boot binary itself isn't it? But > > the memory occupied by the u-boot should already be reserved... > > Yes it is. As long as it doen't overlap with the 64k EFI code page. > See below. Yes, I saw the comment. Which confuses me. The overlap itself shouldn't be a problem since both the spin table and the EFI runtime code page should be preserved. But I guess that the overlap causes problems later on because attempting to reserve overlapping areas fails? > > Unless CONFIG_EFI_LOADER is defined. Then it relocates the spin table > > to memory allocated using efi_allocate_pages(). But that function > > only looks at the EFI memory map to figure out what memory is > > available. So I suspect that it might hand out the same memory as > > lmb_alloc(). It all looks a bit broken to me... > > Yes, that is actually my code ;) The kontron_sl28 is the only > board which uses spin tables as far as I know. It doesn't support > PSCI; at least if you don't load a bl31 TF-A. Therefore, for SMP > it uses spin tables. The relocation code work arounds a problem > with the reserved EFI code, see [1]. > > And yes, it actually is broken. But so might be every code which > is using the efi_allocate_pages(), no? LMB isn't global, but is > just initialized at different places. Like before a linux kernel > is booted or when you load a file (?). And everytime the whole > memory is added, and then different regions are carved out (see > above). Right. So it mostly works because U-Boot either ends up using a code path where it uses LMB or a path where it ends up using the EFI memory map, but never both. Except if it hits your layerscape code. I think the right way to solve this is to allocate the memory for the spin table through some other means and use efi_add_memory_map() to reserve that memory like what is done in board/raspberrypi/rpi/rpi.c. Or don't relocate the spin table and fix the issue with overlapping reserves. Cheers, Mark