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 X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9786C2BA83 for ; Thu, 13 Feb 2020 10:11:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 725802173E for ; Thu, 13 Feb 2020 10:11:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581588663; bh=DcTFDh6Btu9NlaDnpCgIMMBV4IDmzSgnefKuvO9pNK8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=L08R3AiRYQLAM4FitOC2aWgI9fcnV5ItQMHJFkskDnNI3dOX6Lm2++RUl5/jQasQh oegLuUnOGTmdkV77O9tFEIaX87anLF8DAFMX5Q9nVEVc6FRuggQIvils0BOKXEFALB fOGVWq5NEIm8S5tNDNC7qWgjx1B9UonfyT5UDhvs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729653AbgBMKLC (ORCPT ); Thu, 13 Feb 2020 05:11:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:51322 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729428AbgBMKLC (ORCPT ); Thu, 13 Feb 2020 05:11:02 -0500 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 40FAF20873; Thu, 13 Feb 2020 10:11:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581588662; bh=DcTFDh6Btu9NlaDnpCgIMMBV4IDmzSgnefKuvO9pNK8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pjn/5040/9bpqrzAPIPY0NL05Icp8khNKqiWzTH8ehI9lZjKQY8M4aPda7PZocp9E /hHaRaM4IYarz/UZQa8TZE2dKpLxCeCCyXaJlN+Us6LOLCkKDRSWd79d6CpUJVrS2q XaLhsvSH3GdMGKQgNUYRSv0f57KBocrE/1T0jazk= Date: Thu, 13 Feb 2020 10:10:58 +0000 From: Will Deacon To: minyard@acm.org Cc: Catalin Marinas , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 0/2] arm64 kgdb fixes for single stepping Message-ID: <20200213101057.GB1405@willie-the-truck> References: <20200213031131.13255-1-minyard@acm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200213031131.13255-1-minyard@acm.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 12, 2020 at 09:11:29PM -0600, minyard@acm.org wrote: > I got a bug report about using kgdb on arm64, and it turns out it was > fairly broken. Patch 2 has a description of what was going on. I am > using a Marvell 8100 board. > > The following patches fix the problem, but probably not in the > best way. They are what I hacked out to show the problems. > > I am not quite sure how this will interact with kprobes and hardware > breakpoints which use the same code, but they would have been broken, > too, so this is not making them any worse. This should all be handled by kgdb itself, not by changing the low-level debug exception handling. For example, the '&kgdb_step_hook' can take care of re-arming the step state machine and kgdb can also simply disable interrupts during the step if it doesn't want to step into the handler. Will