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 D19B2C433F5 for ; Tue, 18 Jan 2022 11:21:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234582AbiARLV1 (ORCPT ); Tue, 18 Jan 2022 06:21:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232274AbiARLV1 (ORCPT ); Tue, 18 Jan 2022 06:21:27 -0500 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38C5BC061574 for ; Tue, 18 Jan 2022 03:21:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=0YIdVKtdFmfG5n3uavuj6tkK42RYTf7CKBl8Kthf/50=; b=NRDhc81iKhblxcuPAVUy5T3xdg /e+GTGe3VO61jAlAbymAE7azb9l24JZj/lHApv2qKuY+zeMxknnPjnTGi5lPnjLpwXanceKonQ7H+ t99pafBVS6/Ru5BzDOTPqUUCJzPvvuJBG2aFcezJTE7xbYH57E8LYkBK/66Iq8VBrnkrevnWg/IJZ LF024wbwwqFTUzIfm23q1XA9g3dB3DAY6iPx0D1cIKYYhaQg3gpb43Jhj0dEvwX61LzqhLE0oc62Q d8moJClGS5she8pf+ZE7HcEjc6MoMghVxKccME51VsyvAjElM5c6byWcYMYyUC9Iz2xOagFgnY+Le dnqL/ZiQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:56752) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1n9mYD-0003gB-Tx; Tue, 18 Jan 2022 11:21:21 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1n9mYC-0004FC-KL; Tue, 18 Jan 2022 11:21:20 +0000 Date: Tue, 18 Jan 2022 11:21:20 +0000 From: "Russell King (Oracle)" To: Ard Biesheuvel Cc: linux-arm-kernel@lists.infradead.org, arnd@arndb.de, linus.walleij@linaro.org, stable@vger.kernel.org Subject: Re: [PATCH] ARM: Thumb2: align ALT_UP() sections sufficiently Message-ID: References: <20220118102756.1259149-1-ardb@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220118102756.1259149-1-ardb@kernel.org> Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Tue, Jan 18, 2022 at 11:27:56AM +0100, Ard Biesheuvel wrote: > When building for Thumb2, the .alt.smp.init sections that are emitted by > the ALT_UP() patching code may not be 32-bit aligned, even though the > fixup_smp_on_up() routine expects that. This results in alignment faults > at module load time, which need to be fixed up by the fault handler. > > So let's align those sections explicitly, and avoid this from occurring. Are you seeing a problem that this patch fixes? This really should not matter. .alt.smp.init contents are always a whole number of 32-bit words. These are gathered by the linker into the .init.smpalt section, so the contents should always be a whole number of 32-bit words. This follows the .init.tagtable section, which is also a 32-bit word aligned structure built by the linker... which follows the .init.arch.info section and .init.proc.info sections which all have 32-bit alignment requirements. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!