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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E2D49C433EF for ; Fri, 22 Jul 2022 09:11:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235340AbiGVJLp (ORCPT ); Fri, 22 Jul 2022 05:11:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39364 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235277AbiGVJLF (ORCPT ); Fri, 22 Jul 2022 05:11:05 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 08251A0246 for ; Fri, 22 Jul 2022 02:09:33 -0700 (PDT) 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 7962D61F05 for ; Fri, 22 Jul 2022 09:09:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AD9E2C341CE; Fri, 22 Jul 2022 09:09:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1658480972; bh=QQARAL8ZRGtJnkmOAlwG2vpBW61GGATrU3fd8wEd2E8=; h=Date:From:To:Subject:From; b=FSBam89IHk8yTHAJd/n7DMeV0qmZaPp4kvWnoB7uNRhSGYYzserkXXqea0tgQ7EIr orVXe7hHXRnseEA6ygiBE4FeVlBgsKUZEdoXn2Km81wxhWYHh89G3RPyDKdQErt09+ fn1qt+AbPGWO+6pvnpkJWc6XFSJ9bP3xt3/Wqt7QN7hZJbfa2G6VoqaP5eBBjpUtT3 /c8FRieKurNl+ajzEq/43SmyxuHc1nD4EaRrvlN/49LQse4vQRrLskB+h9bdUYtsEH EU2hOkkdUVNEpE1za3GLh6Zd9LiAhv7VclsJAt+B+M926bd9LXiJIIVWN+GGKE9qAs OFXmHSLa5SjUQ== Received: by pali.im (Postfix) id 99A2920A2; Fri, 22 Jul 2022 11:09:29 +0200 (CEST) Date: Fri, 22 Jul 2022 11:09:29 +0200 From: Pali =?utf-8?B?Um9ow6Fy?= To: Christophe Leroy , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Regression: Linux v5.15+ does not boot on Freescale P2020 Message-ID: <20220722090929.mwhmxxdd7yioxqpz@pali> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: NeoMutt/20180716 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello! Trying to boot mainline Linux kernel v5.15+, including current version from master branch, on Freescale P2020 does not work. Kernel does not print anything to serial console, seems that it does not work and after timeout watchdog reset the board. I run git bisect and it found following commit: 9401f4e46cf6965e23738f70e149172344a01eef is the first bad commit commit 9401f4e46cf6965e23738f70e149172344a01eef Author: Christophe Leroy Date: Tue Mar 2 08:48:11 2021 +0000 powerpc: Use lwarx/ldarx directly instead of PPC_LWARX/LDARX macros Force the eh flag at 0 on PPC32. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1fc81f07cabebb875b963e295408cc3dd38c8d85.1614674882.git.christophe.leroy@csgroup.eu :040000 040000 fe6747e45736dfcba74914a9445e5f70f5120600 96358d08b65d3200928a973efb5b969b3d45f2b0 M arch If I revert this commit then kernel boots correctly. It also boots fine if I revert this commit on top of master branch. Freescale P2020 has two 32-bit e500 powerpc cores. Any idea why above commit is causing crash of the kernel? And why it is needed? Could eh flag set to 0 cause deadlock? I have looked into e500 Reference Manual for lwarx instruction (page 562) https://www.nxp.com/files-static/32bit/doc/ref_manual/EREF_RM.pdf and both 0 and 1 values for EH flag should be supported.