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 5919FC43217 for ; Sun, 30 Jan 2022 21:26:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356798AbiA3V0D (ORCPT ); Sun, 30 Jan 2022 16:26:03 -0500 Received: from mga07.intel.com ([134.134.136.100]:9048 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356821AbiA3VZc (ORCPT ); Sun, 30 Jan 2022 16:25:32 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1643577932; x=1675113932; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=qjlVyEBxxP1l305ldO+H2m7erFyvzIp4PIJC/dne3Rw=; b=lWfmWDe1uVtISUbhbJ8UqaWGN9/ekymjl6JmgibJFvJ/a0msOYClGzfB jLgH997zdon7yto4gJxJJGCxnwnHLAsEKSmmFKtq75FGKssnSTi7AYNA6 IuD35YpPW1l/KNHb4/PTIMcRtSbQF9aL+4DXF0RWlkRkf5q4nNptlycr2 fYwjujHg0epPhYNzpHZXLKLWNJxhBENW++5k1I3eDI3OSZe/BzmGfir0w 9N00aTCjLubqv4ISsEKAslFThE4LENdtPN0jSKi1/bieM5hPsXm+/5qKj Am/hMejzL2PUiHc2Huc9U2Dc1Tcko5dBjEH+t9OQzM/5NYXk0jwk9qNyy Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10243"; a="310685840" X-IronPort-AV: E=Sophos;i="5.88,329,1635231600"; d="scan'208";a="310685840" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Jan 2022 13:22:14 -0800 X-IronPort-AV: E=Sophos;i="5.88,329,1635231600"; d="scan'208";a="536857038" Received: from avmallar-mobl1.amr.corp.intel.com (HELO rpedgeco-desk.amr.corp.intel.com) ([10.209.123.171]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Jan 2022 13:22:14 -0800 From: Rick Edgecombe To: 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" , Dave Martin , Weijiang Yang , "Kirill A . Shutemov" , joao.moreira@intel.com, John Allen , kcc@google.com, eranian@google.com Cc: rick.p.edgecombe@intel.com Subject: [PATCH 35/35] x86/cpufeatures: Limit shadow stack to Intel CPUs Date: Sun, 30 Jan 2022 13:18:38 -0800 Message-Id: <20220130211838.8382-36-rick.p.edgecombe@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220130211838.8382-1-rick.p.edgecombe@intel.com> References: <20220130211838.8382-1-rick.p.edgecombe@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Shadow stack is supported on newer AMD processors, but the kernel implementation has not been tested on them. Prevent basic issues from showing up for normal users by disabling shadow stack on all CPUs except Intel until it has been tested. At which point the limitation should be removed. Signed-off-by: Rick Edgecombe --- v1: - New patch. arch/x86/kernel/cpu/common.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 9ee339f5b8ca..7fbfe707a1db 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -517,6 +517,14 @@ __setup("nopku", setup_disable_pku); static __always_inline void setup_cet(struct cpuinfo_x86 *c) { + /* + * Shadow stack is supported on AMD processors, but has not been + * tested. Only support it on Intel processors until this is done. + * At which point, this vendor check should be removed. + */ + if (c->x86_vendor != X86_VENDOR_INTEL) + setup_clear_cpu_cap(X86_FEATURE_SHSTK); + if (!cpu_feature_enabled(X86_FEATURE_SHSTK)) return; -- 2.17.1