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 8EEADC64EC4 for ; Thu, 9 Mar 2023 17:22:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230060AbjCIRWs (ORCPT ); Thu, 9 Mar 2023 12:22:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39816 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229645AbjCIRWX (ORCPT ); Thu, 9 Mar 2023 12:22:23 -0500 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C54FE4DE19; Thu, 9 Mar 2023 09:22:22 -0800 (PST) Received: from zn.tnic (p5de8e9fe.dip0.t-ipconnect.de [93.232.233.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 2FD5D1EC0464; Thu, 9 Mar 2023 18:22:21 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1678382541; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=mxv9hEC3xowLTmvmFVJurKfIxwFTtqwG2eF4dqYJzWc=; b=SK49obZgItT4Z5F3IIn6l60sHQMPZCT+du0YhfY9UfATb/zpIqFvtvH+kn+QPGjKeW7vHm OMnvXPq8cXcj1VFAvaOS04ntDNUniOpg3bqjvWg+IjDikuPn2mi/I3mooKSXKwKxsamuD5 CyiyC/avKhASdDT2vhJNEDITZCO5Yis= Date: Thu, 9 Mar 2023 18:22:16 +0100 From: Borislav Petkov To: "Edgecombe, Rick P" Cc: "david@redhat.com" , "bsingharora@gmail.com" , "hpa@zytor.com" , "Syromiatnikov, Eugene" , "peterz@infradead.org" , "rdunlap@infradead.org" , "keescook@chromium.org" , "Yu, Yu-cheng" , "dave.hansen@linux.intel.com" , "kirill.shutemov@linux.intel.com" , "Eranian, Stephane" , "linux-mm@kvack.org" , "fweimer@redhat.com" , "nadav.amit@gmail.com" , "jannh@google.com" , "dethoma@microsoft.com" , "kcc@google.com" , "linux-arch@vger.kernel.org" , "pavel@ucw.cz" , "oleg@redhat.com" , "hjl.tools@gmail.com" , "Yang, Weijiang" , "Lutomirski, Andy" , "linux-doc@vger.kernel.org" , "arnd@arndb.de" , "tglx@linutronix.de" , "Schimpe, Christina" , "mike.kravetz@oracle.com" , "x86@kernel.org" , "akpm@linux-foundation.org" , "debug@rivosinc.com" , "jamorris@linux.microsoft.com" , "john.allen@amd.com" , "rppt@kernel.org" , "andrew.cooper3@citrix.com" , "mingo@redhat.com" , "corbet@lwn.net" , "linux-kernel@vger.kernel.org" , "linux-api@vger.kernel.org" , "gorcunov@gmail.com" Subject: Re: [PATCH v7 31/41] x86/shstk: Introduce routines modifying shstk Message-ID: <20230309172216.GHZAoVyHoTqLG+YKB4@fat_crate.local> References: <20230227222957.24501-1-rick.p.edgecombe@intel.com> <20230227222957.24501-32-rick.p.edgecombe@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 09, 2023 at 05:03:26PM +0000, Edgecombe, Rick P wrote: > On Thu, 2023-03-09 at 17:48 +0100, Borislav Petkov wrote: > > On Mon, Feb 27, 2023 at 02:29:47PM -0800, Rick Edgecombe wrote: > > > From: Yu-cheng Yu > > > > > > Shadow stacks are normally written to via CALL/RET or specific CET > > > > ^ > > indirectly. > > Dunno here, RSTORSSP/SAVEPREVSSP are kind of direct. > > > > > > instructions like RSTORSSP/SAVEPREVSSP. However during some Linux > > > operations the kernel will need to write to directly using the ^^^^^^^^^ Yes, I was trying to make the contrast more obvious because you say "directly" here. But not too important. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette