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 51A61CA9EAF for ; Mon, 21 Oct 2019 16:57:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E84D2064B for ; Mon, 21 Oct 2019 16:57:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727976AbfJUQ5R (ORCPT ); Mon, 21 Oct 2019 12:57:17 -0400 Received: from [217.140.110.172] ([217.140.110.172]:58462 "EHLO foss.arm.com" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1726672AbfJUQ5Q (ORCPT ); Mon, 21 Oct 2019 12:57:16 -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 E63D31715; Mon, 21 Oct 2019 09:56:53 -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 3FF163F71F; Mon, 21 Oct 2019 09:56:52 -0700 (PDT) Date: Mon, 21 Oct 2019 17:56:50 +0100 From: Mark Rutland To: Sami Tolvanen Cc: Will Deacon , Catalin Marinas , Steven Rostedt , Ard Biesheuvel , Dave Martin , Kees Cook , Laura Abbott , Nick Desaulniers , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 13/18] arm64: preserve x18 when CPU is suspended Message-ID: <20191021165649.GE56589@lakrids.cambridge.arm.com> References: <20191018161033.261971-1-samitolvanen@google.com> <20191018161033.261971-14-samitolvanen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191018161033.261971-14-samitolvanen@google.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 On Fri, Oct 18, 2019 at 09:10:28AM -0700, Sami Tolvanen wrote: > Don't lose the current task's shadow stack when the CPU is suspended. > > Signed-off-by: Sami Tolvanen > --- > arch/arm64/mm/proc.S | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S > index fdabf40a83c8..9a8bd4bc8549 100644 > --- a/arch/arm64/mm/proc.S > +++ b/arch/arm64/mm/proc.S > @@ -73,6 +73,9 @@ alternative_endif > stp x8, x9, [x0, #48] > stp x10, x11, [x0, #64] > stp x12, x13, [x0, #80] > +#ifdef CONFIG_SHADOW_CALL_STACK > + stp x18, xzr, [x0, #96] > +#endif This should have a corresponding change to cpu_suspend_ctx in . Otherwise we're corrupting a portion of the stack. Mark. > ret > ENDPROC(cpu_do_suspend) > > @@ -89,6 +92,9 @@ ENTRY(cpu_do_resume) > ldp x9, x10, [x0, #48] > ldp x11, x12, [x0, #64] > ldp x13, x14, [x0, #80] > +#ifdef CONFIG_SHADOW_CALL_STACK > + ldp x18, x19, [x0, #96] > +#endif > msr tpidr_el0, x2 > msr tpidrro_el0, x3 > msr contextidr_el1, x4 > -- > 2.23.0.866.gb869b98d4c-goog >