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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B08FC433FE for ; Mon, 3 Oct 2022 14:01:37 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9BC416B0072; Mon, 3 Oct 2022 10:01:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 944816B0073; Mon, 3 Oct 2022 10:01:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7BE138E0001; Mon, 3 Oct 2022 10:01:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 63A896B0072 for ; Mon, 3 Oct 2022 10:01:36 -0400 (EDT) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 2EA0B160A3A for ; Mon, 3 Oct 2022 14:01:36 +0000 (UTC) X-FDA: 79979800992.01.38AFBE8 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by imf22.hostedemail.com (Postfix) with ESMTP id 3CDB6C005A for ; Mon, 3 Oct 2022 14:01:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1664805691; x=1696341691; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=ddjztWhV3UUDkLswvk71WAdPtvy3j53/6CHOczkz9O8=; b=kSCWgRBruC00mzhQuVuffK1Pkao5WkJFXX9h3tM1DAME53KASAjRg6Zj BqFVOaN8SNVmypvpwnFArJ0CkM04dS3Mu3W0W93Hn/e6rR2z+M0NaLuY2 FuTcNir+XFKUAmldTjH32H/8FIA06uUDJVjh0WQLRer391A/vubHx6L+x ZrRezNvDbbt8BlOeezol8e2bigjM5k/RoH53s3tAkMQ2HK6SxPaYzBYa3 wBImncq6rTByiFU90qjQYlAhUsZhqrvZM0JVQlhl0LM0FfEN5gWkVjHSW jE+xv1NmeaaRIK2SU/GBBmmVHJLWWNo+SPWP9t6Rrk2bwxoooj1AGRIYV w==; X-IronPort-AV: E=McAfee;i="6500,9779,10489"; a="304125162" X-IronPort-AV: E=Sophos;i="5.93,365,1654585200"; d="scan'208";a="304125162" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Oct 2022 07:01:25 -0700 X-IronPort-AV: E=McAfee;i="6500,9779,10489"; a="798729084" X-IronPort-AV: E=Sophos;i="5.93,365,1654585200"; d="scan'208";a="798729084" Received: from bandrei-mobl.ger.corp.intel.com (HELO box.shutemov.name) ([10.252.37.219]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Oct 2022 07:01:12 -0700 Received: by box.shutemov.name (Postfix, from userid 1000) id 9751D104CE4; Mon, 3 Oct 2022 17:01:09 +0300 (+03) Date: Mon, 3 Oct 2022 17:01:09 +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 , Michael Kerrisk Subject: Re: [PATCH v2 07/39] x86/cet: Add user control-protection fault handler Message-ID: <20221003140109.jgn3per7vbthifn5@box.shutemov.name> References: <20220929222936.14584-1-rick.p.edgecombe@intel.com> <20220929222936.14584-8-rick.p.edgecombe@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220929222936.14584-8-rick.p.edgecombe@intel.com> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1664805692; a=rsa-sha256; cv=none; b=d4AmLcysyP5mhtv3gSiawPAOQiwy1VJm6wWQOv3kaSSHikScIMeE2pRaQ9n7zXP6OdwVQB 3uFAMHXaTt+mmTRMEONOJs7AsMqQlSXkztEJU6aF4RllGyRxPNsTZ9mr1wKYIWIkLekAnf yZ2iPu4KBHhQ1SZRbVJb4lD9h9TiF2E= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=kSCWgRBr; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none); spf=none (imf22.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.65) smtp.mailfrom=kirill.shutemov@linux.intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1664805692; h=from:from:sender: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:dkim-signature; bh=PFa/4AdkKq6pX6Vg322SQhs/6uo42/sbH3bURV6MDUM=; b=7iq3FAeIyo2SeZifBENtaz4wE/zCDiy2rTO0oAaJrqMkL9EPEh1fg3bdNBidEtknyFdwgY rookNQh5w+6T7I20nvHAskJO0tZRFwfQ7yg92KUzsVPZgJM1kYXl7DbNtGU1jFgUSEYBzN 2kOglc/XAdRVsUjaydzhSbLhIFKzKV8= X-Rspam-User: Authentication-Results: imf22.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=kSCWgRBr; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none); spf=none (imf22.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.65) smtp.mailfrom=kirill.shutemov@linux.intel.com X-Stat-Signature: t5myzqogk16nux6cdz6jd838hqhcen8f X-Rspamd-Queue-Id: 3CDB6C005A X-Rspamd-Server: rspam09 X-HE-Tag: 1664805690-141199 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Sep 29, 2022 at 03:29:04PM -0700, Rick Edgecombe wrote: > +#else > +static void do_user_control_protection_fault(struct pt_regs *regs, > + unsigned long error_code) > +{ > + WARN_ONCE(1, "User-mode control protection fault with shadow support disabled\n"); Why is this a warning, but runtime check for !X86_FEATURE_IBT and !X86_FEATURE_SHSTK below is fatal? > +} > +#endif > + > +#ifdef CONFIG_X86_KERNEL_IBT > + > +static __ro_after_init bool ibt_fatal = true; > + > +extern void ibt_selftest_ip(void); /* code label defined in asm below */ > > +static void do_kernel_control_protection_fault(struct pt_regs *regs) > +{ > if (unlikely(regs->ip == (unsigned long)&ibt_selftest_ip)) { > regs->ax = 0; > return; > @@ -283,9 +335,29 @@ static int __init ibt_setup(char *str) > } > > __setup("ibt=", ibt_setup); > - > +#else > +static void do_kernel_control_protection_fault(struct pt_regs *regs) > +{ > + WARN_ONCE(1, "Kernel-mode control protection fault with IBT disabled\n"); Ditto. > +} > #endif /* CONFIG_X86_KERNEL_IBT */ > > +#if defined(CONFIG_X86_KERNEL_IBT) || defined(CONFIG_X86_SHADOW_STACK) > +DEFINE_IDTENTRY_ERRORCODE(exc_control_protection) > +{ > + if (!cpu_feature_enabled(X86_FEATURE_IBT) && > + !cpu_feature_enabled(X86_FEATURE_SHSTK)) { > + pr_err("Unexpected #CP\n"); > + BUG(); > + } > + > + if (user_mode(regs)) > + do_user_control_protection_fault(regs, error_code); > + else > + do_kernel_control_protection_fault(regs); > +} > +#endif /* defined(CONFIG_X86_KERNEL_IBT) || defined(CONFIG_X86_SHADOW_STACK) */ > + > #ifdef CONFIG_X86_F00F_BUG > void handle_invalid_op(struct pt_regs *regs) > #else -- Kiryl Shutsemau / Kirill A. Shutemov