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 69B7AC43219 for ; Mon, 3 Oct 2022 13:40:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229548AbiJCNkW (ORCPT ); Mon, 3 Oct 2022 09:40:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57890 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229864AbiJCNkS (ORCPT ); Mon, 3 Oct 2022 09:40:18 -0400 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 520202936D; Mon, 3 Oct 2022 06:40:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1664804417; x=1696340417; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=+5qCpWO+BAGW3ExOyW3chioNW0LHy3lT3j4pg7MiQnQ=; b=OOOksX1axHfX1SVR+j4lORPLuVLsK7iwzxqWdv6ApHo38UIGUD5DsgI6 DS2UKQPzmtIpOjKtBynm0y8ig/SQbmU7Voq4AYonpgFjt4o5A4RWs5vgw L20DqmmJTRMDC69VHNVL1L6pp0eJUcPEqJUD7grm0rc7fKw66j/lhfBew srJqETT1T9DSAIkxJg7jpDzfzvuPpRoTDvYGg1G5eH7xnwygVFNP+bXnB LPFi11WXwovj+EFuXoG9m466JpNm5HC44ySawY09MNBqcqHgCbNksPoCS u6vUxznHfEnbBGEESA+gwkhNmRlcKyyVFvkibI/JkpMmX7J2DoEzkYkyj Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10489"; a="283003462" X-IronPort-AV: E=Sophos;i="5.93,365,1654585200"; d="scan'208";a="283003462" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Oct 2022 06:40:16 -0700 X-IronPort-AV: E=McAfee;i="6500,9779,10489"; a="952343480" X-IronPort-AV: E=Sophos;i="5.93,365,1654585200"; d="scan'208";a="952343480" Received: from bandrei-mobl.ger.corp.intel.com (HELO box.shutemov.name) ([10.252.37.219]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Oct 2022 06:40:08 -0700 Received: by box.shutemov.name (Postfix, from userid 1000) id 7FA5C104CE4; Mon, 3 Oct 2022 16:40:06 +0300 (+03) Date: Mon, 3 Oct 2022 16:40:06 +0300 From: "Kirill A . Shutemov" To: Rick Edgecombe Cc: x86@kernel.org, "H . Peter Anvin" , Thomas Gleixner , 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" , Weijiang Yang , joao.moreira@intel.com, John Allen , kcc@google.com, eranian@google.com, rppt@kernel.org, jamorris@linux.microsoft.com, dethoma@microsoft.com, Yu-cheng Yu Subject: Re: [PATCH v2 02/39] x86/cet/shstk: Add Kconfig option for Shadow Stack Message-ID: <20221003134006.yoye7dvywuec6bco@box.shutemov.name> References: <20220929222936.14584-1-rick.p.edgecombe@intel.com> <20220929222936.14584-3-rick.p.edgecombe@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220929222936.14584-3-rick.p.edgecombe@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 29, 2022 at 03:28:59PM -0700, Rick Edgecombe wrote: > From: Yu-cheng Yu > > Shadow Stack provides protection against function return address > corruption. It is active when the processor supports it, the kernel has > CONFIG_X86_SHADOW_STACK enabled, and the application is built for the > feature. This is only implemented for the 64-bit kernel. When it is > enabled, legacy non-Shadow Stack applications continue to work, but without > protection. > > Signed-off-by: Yu-cheng Yu > Co-developed-by: Rick Edgecombe > Signed-off-by: Rick Edgecombe > Cc: Kees Cook > > --- > > v2: > - Remove already wrong kernel size increase info (tlgx) > - Change prompt to remove "Intel" (tglx) > - Update line about what CPUs are supported (Dave) > > Yu-cheng v25: > - Remove X86_CET and use X86_SHADOW_STACK directly. > > Yu-cheng v24: > - Update for the splitting X86_CET to X86_SHADOW_STACK and X86_IBT. > > arch/x86/Kconfig | 18 ++++++++++++++++++ > arch/x86/Kconfig.assembler | 5 +++++ > 2 files changed, 23 insertions(+) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index f9920f1341c8..b68eb75887b8 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -26,6 +26,7 @@ config X86_64 > depends on 64BIT > # Options that are inherently 64-bit kernel only: > select ARCH_HAS_GIGANTIC_PAGE > + select ARCH_HAS_SHADOW_STACK > select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 > select ARCH_USE_CMPXCHG_LOCKREF > select HAVE_ARCH_SOFT_DIRTY > @@ -1936,6 +1937,23 @@ config X86_SGX > > If unsure, say N. > > +config ARCH_HAS_SHADOW_STACK > + def_bool n Hm. Shouldn't ARCH_HAS_SHADOW_STACK definition be in arch/Kconfig, not under arch/x86? Also, I think "def_bool n" has the same meaning as just "bool", no? > + > +config X86_SHADOW_STACK > + prompt "X86 Shadow Stack" > + def_bool n Maybe just bool "X86 Shadow Stack" ? > + 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. Today the kernel's support is limited to > + virtualizing it in KVM guests. > + > + CPUs supporting shadow stacks were first released in 2020. > + > + If unsure, say N. > + > config EFI > bool "EFI runtime service support" > depends on ACPI > diff --git a/arch/x86/Kconfig.assembler b/arch/x86/Kconfig.assembler > index 26b8c08e2fc4..00c79dd93651 100644 > --- a/arch/x86/Kconfig.assembler > +++ b/arch/x86/Kconfig.assembler > @@ -19,3 +19,8 @@ config AS_TPAUSE > def_bool $(as-instr,tpause %ecx) > help > Supported by binutils >= 2.31.1 and LLVM integrated assembler >= V7 > + > +config AS_WRUSS > + def_bool $(as-instr,wrussq %rax$(comma)(%rbx)) > + help > + Supported by binutils >= 2.31 and LLVM integrated assembler > -- > 2.17.1 > -- Kiryl Shutsemau / Kirill A. Shutemov