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 A7513C28D13 for ; Thu, 25 Aug 2022 07:53:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236411AbiHYHxT (ORCPT ); Thu, 25 Aug 2022 03:53:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234910AbiHYHxK (ORCPT ); Thu, 25 Aug 2022 03:53:10 -0400 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ACA69A00E6; Thu, 25 Aug 2022 00:53:08 -0700 (PDT) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4MCwDt5BS1z4xV9; Thu, 25 Aug 2022 17:53:02 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1661413983; bh=UtVip1icK7gJdBlHq+HFWJBnOoW3QoCQ+h8pU+n3KkA=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=ZLFEHd4Sc+LArWxSHPMZaxUV5Xt5HbCBwxEJoAOkDftQUBd3UvDzQ3SPoUGfIq8+Y XOXVABGmUJRXNewPOhBZ4PnZBgAclyRWiDmLWWWIEoOxbTyf0lT9HmzLfn6qDXHVP8 4cFLNr2mtb3VMBT0+X8XSw8kOQcDbMBET6kwqKOBcIoT5DWSkK5aoD9YgXXoTklXi4 4vn7aZmWvMmRDrzEWJ1c3IdlA0o+UvHCBus9SLXerZ9zIaIxILLCzH95mjf0d5/kTH Nh5wLMJbIfMZsTuGrUc2j6C3xLq/AaC3ujgNFv8DeGoG8jRuDO1B7lmoCz2us+rszT QVS80HXLzHXbw== From: Michael Ellerman To: Masahiro Yamada , Nicholas Piggin , Christophe Leroy , linuxppc-dev@lists.ozlabs.org Cc: linux-kbuild@vger.kernel.org, Masahiro Yamada , linux-kernel@vger.kernel.org Subject: Re: [PATCH] powerpc: align syscall table for ppc32 In-Reply-To: <20220820165129.1147589-1-masahiroy@kernel.org> References: <20220820165129.1147589-1-masahiroy@kernel.org> Date: Thu, 25 Aug 2022 17:53:02 +1000 Message-ID: <874jy0lpy9.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Masahiro Yamada writes: > Christophe Leroy reported that commit 7b4537199a4a ("kbuild: link > symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS") broke > mpc85xx_defconfig + CONFIG_RELOCATABLE=y. > > LD vmlinux > SYSMAP System.map > SORTTAB vmlinux > CHKREL vmlinux > WARNING: 451 bad relocations > c0b312a9 R_PPC_UADDR32 .head.text-0x3ff9ed54 > c0b312ad R_PPC_UADDR32 .head.text-0x3ffac224 > c0b312b1 R_PPC_UADDR32 .head.text-0x3ffb09f4 > c0b312b5 R_PPC_UADDR32 .head.text-0x3fe184dc > c0b312b9 R_PPC_UADDR32 .head.text-0x3fe183a8 > ... > > The compiler emits a bunch of R_PPC_UADDR32, which is not supported by > arch/powerpc/kernel/reloc_32.S. > > The reason is there exists an unaligned symbol. > > $ powerpc-linux-gnu-nm -n vmlinux > ... > c0b31258 d spe_aligninfo > c0b31298 d __func__.0 > c0b312a9 D sys_call_table > c0b319b8 d __func__.0 > > Commit 7b4537199a4a is not the root cause. Even before that, I can > reproduce the same issue for mpc85xx_defconfig + CONFIG_RELOCATABLE=y > + CONFIG_MODVERSIONS=n. > > It is just that nobody did not notice it because when CONFIG_MODVERSIONS > is enabled, a __crc_* symbol inserted before sys_call_table was hiding > the unalignment issue. > > I checked the commit history, but I could not understand commit > 46b45b10f142 ("[POWERPC] Align the sys_call_table"). > > It said 'Our _GLOBAL macro does a ".align 2" so the alignment is fine > for 32 bit'. I checked the _GLOBAL in include/asm-powerpc/ppc_asm.h > at that time. _GLOBAL specifies ".align 2" for ppc64, but no .align > for ppc32. > > Commit c857c43b34ec ("powerpc: Don't use a function descriptor for > system call table") removed _GLOBAL from the syscall table. > > Anyway, adding alignment to the syscall table for ppc32 fixes the issue. > > I am not giving Fixes tag because I do not know since when it has been > broken, but presumably it has been for a long while. Thanks. I trimmed the change log a bit just to say ~= it's been broken for ever, and added a Cc to stable. cheers