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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 5FC07C10F29 for ; Tue, 17 Mar 2020 12:10:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3469F2073C for ; Tue, 17 Mar 2020 12:10:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726882AbgCQMKz (ORCPT ); Tue, 17 Mar 2020 08:10:55 -0400 Received: from foss.arm.com ([217.140.110.172]:36328 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726634AbgCQMKy (ORCPT ); Tue, 17 Mar 2020 08:10:54 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 52B6A30E; Tue, 17 Mar 2020 05:10:54 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6E6613F534; Tue, 17 Mar 2020 05:10:53 -0700 (PDT) Date: Tue, 17 Mar 2020 12:10:51 +0000 From: Mark Rutland To: Hongbo Yao Cc: will@kernel.org, broonie@kernel.org, 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: <20200317121050.GH8831@lakrids.cambridge.arm.com> References: <20200317114708.109283-1-yaohongbo@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200317114708.109283-1-yaohongbo@huawei.com> User-Agent: Mutt/1.11.1+11 (2f07cb52) (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Adding Catalin and LAKML] Mark. On Tue, Mar 17, 2020 at 07:47:08PM +0800, Hongbo Yao wrote: > Kpti cannot be disabled from the kernel cmdline after the commit > 09e3c22a("arm64: Use a variable to store non-global mappings decision"). > > Bring back the missing check of kpti= command-line option to fix the > case where the SPE driver complains the missing "kpti-off" even it has > already been set. > > Signed-off-by: Hongbo Yao > --- > arch/arm64/include/asm/mmu.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h > index 3c9533322558..ebbc0d3ac2f7 100644 > --- a/arch/arm64/include/asm/mmu.h > +++ b/arch/arm64/include/asm/mmu.h > @@ -34,7 +34,8 @@ extern bool arm64_use_ng_mappings; > > static inline bool arm64_kernel_unmapped_at_el0(void) > { > - return arm64_use_ng_mappings; > + return arm64_use_ng_mappings && > + cpus_have_const_cap(ARM64_UNMAP_KERNEL_AT_EL0); > } > > typedef void (*bp_hardening_cb_t)(void); > -- > 2.20.1 >