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 61D7DC433F5 for ; Wed, 30 Mar 2022 16:37:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347915AbiC3Qis (ORCPT ); Wed, 30 Mar 2022 12:38:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37010 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236846AbiC3Qiq (ORCPT ); Wed, 30 Mar 2022 12:38:46 -0400 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 81F7E197AC2 for ; Wed, 30 Mar 2022 09:37:01 -0700 (PDT) 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=HWbPC5h/j58ceCxQlVSc5RvAYIlhggFe0pdxq+KiTPE=; b=ohc2cMwku7X0vVNhI8K19tG2iF uwO+P1yiW7VcQk8CMgq9EFPtfMFJaMmTkhiFga1tEaFJGGWZablr6Pe7JksjV3ecd4CLc6dEN/X4i M2H5zvv4h7OiKykxMtwjlXckE+aKI6WAc6TkiKj5QtneCteTW9PiQc+TN/zrCmP+e1cQuWnIES6SC +7za02u1fvjlc6uCSHGq3WtJd7s8uFdU9jtlG98tSXCtGlcodHnC9dfhl26JGVZmy4763GNFIfxZz TRGeS+ssw57B10Kuq9RcPztTFn96FjyOxjjdORnFDLQlKiCTuc55qFPDozZ+sGZfetTHTlN0Cl8/M xG+Xy6lA==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:58024) 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 1nZbJY-0003T8-Pt; Wed, 30 Mar 2022 17:36:56 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1nZbJX-0006mF-G3; Wed, 30 Mar 2022 17:36:55 +0100 Date: Wed, 30 Mar 2022 17:36:55 +0100 From: "Russell King (Oracle)" To: Ard Biesheuvel Cc: Christian Eggers , Linux ARM , Catalin Marinas , Linux Kernel Mailing List , llvm@lists.linux.dev, Nathan Chancellor Subject: Re: CONFIG_THUMB2_KERNEL=y boot failure after Spectre BHB fixes Message-ID: References: <2109354.irdbgypaU6@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 30, 2022 at 06:34:25PM +0200, Ard Biesheuvel wrote: > On Wed, 30 Mar 2022 at 18:12, Russell King (Oracle) > wrote: > > > > On Tue, Mar 22, 2022 at 06:49:17PM +0100, Christian Eggers wrote: > > > Hi Nathan, hi Russel, > > > > > > I stumbled today over the same problem (no output on serial console > > > with v5.15.28-rt36). During `git bisect`, I had also some commits > > > where a few lines of output were visible. > > > > > > At commit 8d9d651ff227 ("ARM: use LOADADDR() to get load address of > > > sections"), the system boots up to here: > > > > > > start_kernel() > > > +--setup_arch() > > > +--paging_init() > > > +--devicemaps_init() > > > +--eary_trap_init(vectors_base = 0xC7FFE000) > > > +--copy_from_lma(vectors_base = 0xC7FFE000, __vectors_start=0x0, __vectors_end=0x20) > > > +--__memcpy() > > > > > > copy_template.S:113 > > > ldr8w r1, r3, r4, r5, r6, r7, r8, ip, lr, abort=20f > > > r1 = 0 > > > > > > > > > With the final v5.15.28-rt36 I found out that the system boots fine > > > after disabling CONFIG_HARDEN_BRANCH_HISTORY. > > > > > > Is there anything else I could analyze? My SoC system is a NXP i.MX6LL > > > with a ARMv7 core. I have access to a JTAG debugger. > > > > I think this is already fixed in mainline. Commit: > > > > 6c7cb60bff7a ("ARM: fix Thumb2 regression") > > > > It's still broken - I sent a couple of patches on Monday, among which > one to fix the boot issue with loop8 on Thumb2. The problem is 'b . + > 4', which produces a narrow encoding, and so it skips the subsequent > subs instruction and loops forever. And what's the current status? Sorry, I've way too much email from the last 2.5 weeks to find it myself. Thanks. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!