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 C3B15C433EF for ; Tue, 8 Feb 2022 08:41:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351263AbiBHIlf (ORCPT ); Tue, 8 Feb 2022 03:41:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37862 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350981AbiBHIlL (ORCPT ); Tue, 8 Feb 2022 03:41:11 -0500 X-Greylist: delayed 167 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Tue, 08 Feb 2022 00:41:08 PST Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 662ADC0401F6; Tue, 8 Feb 2022 00:41:08 -0800 (PST) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1644309666; 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: in-reply-to:in-reply-to:references:references; bh=+It4P3xPoeH5J/e9lA7VjY28XpNcFDRoZRHbbjMbu5U=; b=FMUUbamEpDp9Twu7NkDpbKNalho/IRBoc5L5fW5X+KyAlt7aQ9D0z0Lepxl4pVat9hEh6M pFCNv+ciIZAdbt5WZnVwcbgYfcUkeU4Yo+9/EdyaF8auAQnV0fIYvDdpwRxx9no4FdLc5w c95kK+H3Lf8rIw9jp4zdT0QB1GmDQCeec9dq4ok1tc+kWoNkWCOJcxI5UB2YwvfpbmEXnK 9zo5yjhU2lQmzw49yC7HhrmaegQT9oSRI/0m08jBTFK9S+JvZVS7vmwGtaz2MU1Pyws3+w AUtH0FFTBLTv1OQRrLTBw3hgbOTCrkziqylp282nVqOUvvOxntVKWHmJ7Dxh/A== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1644309666; 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: in-reply-to:in-reply-to:references:references; bh=+It4P3xPoeH5J/e9lA7VjY28XpNcFDRoZRHbbjMbu5U=; b=7uifLMqFDvP10anvdiJQ9zvhl249BUxbV/w40H0HuQ5ADnPZLqP2GPkJNDpnQGgrLnrBAa MA8hB6MQm3fWwaCg== To: Dave Hansen , Rick Edgecombe , x86@kernel.org, "H . Peter Anvin" , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H . J . Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V . Shankar" , Dave Martin , Weijiang Yang , "Kirill A . Shutemov" , joao.moreira@intel.com, John Allen , kcc@google.com, eranian@google.com Cc: Yu-cheng Yu Subject: Re: [PATCH 02/35] x86/cet/shstk: Add Kconfig option for Shadow Stack In-Reply-To: <248ef880-025d-54ce-f3ce-fed0e50a0445@intel.com> References: <20220130211838.8382-1-rick.p.edgecombe@intel.com> <20220130211838.8382-3-rick.p.edgecombe@intel.com> <248ef880-025d-54ce-f3ce-fed0e50a0445@intel.com> Date: Tue, 08 Feb 2022 09:41:06 +0100 Message-ID: <87sfstvjh9.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 07 2022 at 14:39, Dave Hansen wrote: > On 1/30/22 13:18, Rick Edgecombe wrote: >> +config X86_SHADOW_STACK >> + prompt "Intel Shadow Stack" >> + def_bool n >> + depends on AS_WRUSS >> + depends on ARCH_HAS_SHADOW_STACK >> + select ARCH_USES_HIGH_VMA_FLAGS >> + help >> + Shadow Stack protection is a hardware feature that detects function >> + return address corruption. This helps mitigate ROP attacks. >> + Applications must be enabled to use it, and old userspace does not >> + get protection "for free". >> + Support for this feature is present on Tiger Lake family of >> + processors released in 2020 or later. Enabling this feature >> + increases kernel text size by 3.7 KB. > > I guess the "2020" comment is still OK. But, given that it's on AMD and > a could of other Intel models, maybe we should just leave this at: > > CPUs supporting shadow stacks were first released in 2020. Yes. > If we say anything. We mostly want folks to just go read the > documentation if they needs more details. Also the kernel text size increase blurb is pretty useless as that's a number which is wrong from day one. Thanks, tglx