From patchwork Wed Mar 20 16:21:14 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 10862191 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C6A9813B5 for ; Wed, 20 Mar 2019 16:25:49 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A8F7D22376 for ; Wed, 20 Mar 2019 16:25:49 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9D55028807; Wed, 20 Mar 2019 16:25:49 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 40ED528A22 for ; Wed, 20 Mar 2019 16:25:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727563AbfCTQZt (ORCPT ); Wed, 20 Mar 2019 12:25:49 -0400 Received: from mga01.intel.com ([192.55.52.88]:41564 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727089AbfCTQZs (ORCPT ); Wed, 20 Mar 2019 12:25:48 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Mar 2019 09:25:48 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,249,1549958400"; d="scan'208";a="135715824" Received: from sorenthe-mobl1.ger.corp.intel.com (HELO localhost) ([10.249.254.203]) by orsmga003.jf.intel.com with ESMTP; 20 Mar 2019 09:25:37 -0700 From: Jarkko Sakkinen To: linux-kernel@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org Cc: akpm@linux-foundation.org, dave.hansen@intel.com, sean.j.christopherson@intel.com, nhorman@redhat.com, npmccallum@redhat.com, serge.ayoun@intel.com, shay.katz-zamir@intel.com, haitao.huang@intel.com, andriy.shevchenko@linux.intel.com, tglx@linutronix.de, kai.svahn@intel.com, bp@alien8.de, josh@joshtriplett.org, luto@kernel.org, kai.huang@intel.com, rientjes@google.com, Andy Lutomirski , Jarkko Sakkinen , Dave Hansen Subject: [PATCH v19,RESEND 22/27] x86/fault: Attempt to fixup unhandled #PF in vDSO before signaling Date: Wed, 20 Mar 2019 18:21:14 +0200 Message-Id: <20190320162119.4469-23-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190320162119.4469-1-jarkko.sakkinen@linux.intel.com> References: <20190320162119.4469-1-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Sean Christopherson vDSO functions can now leverage an exception fixup mechanism similar to kernel exception fixup. For vDSO exception fixup, the initial user is Intel's Software Guard Extensions (SGX), which will wrap the low-level transitions to/from the enclave, i.e. EENTER and ERESUME instructions, in a vDSO function and leverage fixup to intercept exceptions that would otherwise generate a signal. This allows the vDSO wrapper to return the fault information directly to its caller, obviating the need for SGX applications and libraries to juggle signal handlers. Attempt to fixup vDSO exceptions immediately prior to populating and sending signal information. Except for the delivery mechanism, an exception in a vDSO function should be treated like any other exception in userspace, e.g. any fault that is successfully handled by the kernel should not be directly visible to userspace. Suggested-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Jarkko Sakkinen Cc: Dave Hansen Cc: Josh Triplett Signed-off-by: Sean Christopherson --- arch/x86/mm/fault.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 5babd515f616..13be0c67379e 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -28,6 +28,7 @@ #include /* vma_pkey() */ #include /* efi_recover_from_page_fault()*/ #include /* store_idt(), ... */ +#include /* fixup_vdso_exception() */ #define CREATE_TRACE_POINTS #include @@ -936,6 +937,9 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code, sanitize_error_code(address, &error_code); + if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code, address)) + return; + if (likely(show_unhandled_signals)) show_signal_msg(regs, error_code, address, tsk); @@ -1055,6 +1059,9 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address, sanitize_error_code(address, &error_code); + if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code, address)) + return; + set_signal_archinfo(address, error_code); #ifdef CONFIG_MEMORY_FAILURE