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, 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 0CE30C10DCE for ; Wed, 18 Mar 2020 20:13:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D38102077A for ; Wed, 18 Mar 2020 20:13:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584562387; bh=pe4t1TUdWt373Ez1EnHNV+7ooE3eThnbOn1Mljp2GuQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=H6upOJX3uFarKVxTtIuuI+84ChEcmzw+TkSGGWDmjy2ZFJdN6+eHMDbsrMhoVIL6h TZbg5Obvj1NwW11rgXOK9/9eRNastvd0iXC+DmKbgrjZ3yQxjz489m9wCkYzP/MRm5 ki3NWqNERMhjL0rVTAqJIM+0BZ6gtQHyZI+Y70g4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727065AbgCRUNG (ORCPT ); Wed, 18 Mar 2020 16:13:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:55782 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726647AbgCRUNG (ORCPT ); Wed, 18 Mar 2020 16:13:06 -0400 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 56EEF2071C; Wed, 18 Mar 2020 20:13:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584562385; bh=pe4t1TUdWt373Ez1EnHNV+7ooE3eThnbOn1Mljp2GuQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fJfc1ht/bYxSxn6MowvslrLRwT9YTkQYplJpTElDcJogHBcmdK0MT1NWSEncYrRFw 5+Fl9RF+m9QrQZoPXmFeB64y1NrjrT8m40A/WV2rYnfZVte49RVauotNPueT+RwzQR W8fAahaG7Zx3ewn3MZDnu8JgRwY9AqocH74w51lg= Date: Wed, 18 Mar 2020 20:13:00 +0000 From: Will Deacon To: Mark Brown Cc: Mark Rutland , Hongbo Yao , linux-kernel@vger.kernel.org, catalin.marinas@arm.com, linux-arm-kernel@lists.infradead.org Subject: Re: [RFC PATCH] arm64: fix the missing ktpi= cmdline check in arm64_kernel_unmapped_at_el0() Message-ID: <20200318201259.GA7463@willie-the-truck> References: <20200317114708.109283-1-yaohongbo@huawei.com> <20200317121050.GH8831@lakrids.cambridge.arm.com> <20200317124323.GA16200@willie-the-truck> <20200317135719.GH3971@sirena.org.uk> <20200317151813.GA16579@willie-the-truck> <20200317163638.GI3971@sirena.org.uk> <20200317210154.GA19752@willie-the-truck> <20200318113217.GA4553@sirena.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200318113217.GA4553@sirena.org.uk> 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, Mar 18, 2020 at 11:32:17AM +0000, Mark Brown wrote: > On Tue, Mar 17, 2020 at 09:01:54PM +0000, Will Deacon wrote: > > On Tue, Mar 17, 2020 at 04:36:38PM +0000, Mark Brown wrote: > > > > I'd need to go back and retest to confirm but it looks like always had > > > the issue that we'd install some nG mappings early even with KPTI > > > disabled on the command line so your change is just restoring the > > > previous behaviour and we're no worse than we were before. > > > Urgh, this code brings back really bad memories :( :( :( > > Tell me about it. > > > So I've hacked the following, which appears to work but damn I'd like > > somebody else to look at this. I also have a nagging feeling that you > > implemented it like this at some point, but we tried to consolidate things > > during review. > > > Thoughts? > > I don't think I did *exactly* this but it's familiar yeah. It looks > sensible and I can't think of any problems but that doesn't mean there > aren't any. Well, thanks for having a look! Hongbo -- please can you confirm that this fixes the problem that you are seeing? Will