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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67349C04EBF for ; Wed, 5 Dec 2018 23:20:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3612B205C9 for ; Wed, 5 Dec 2018 23:20:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3612B205C9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728875AbeLEXUe (ORCPT ); Wed, 5 Dec 2018 18:20:34 -0500 Received: from mga06.intel.com ([134.134.136.31]:24296 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727592AbeLEXU3 (ORCPT ); Wed, 5 Dec 2018 18:20:29 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Dec 2018 15:20:28 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,320,1539673200"; d="scan'208";a="281279557" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.154]) by orsmga005.jf.intel.com with ESMTP; 05 Dec 2018 15:20:28 -0800 From: Sean Christopherson To: Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, Dave Hansen , Peter Zijlstra Cc: "H. Peter Anvin" , linux-kernel@vger.kernel.org, Andy Lutomirski , Jarkko Sakkinen , Josh Triplett Subject: [RFC PATCH 2/4] x86/fault: Attempt to fixup unhandled #PF in vDSO before signaling Date: Wed, 5 Dec 2018 15:20:10 -0800 Message-Id: <20181205232012.28920-3-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181205232012.28920-1-sean.j.christopherson@intel.com> References: <20181205232012.28920-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Call fixup_vdso_exception() in the SIGSEGV and SIGBUS paths to attempt to fixup page faults in vDSO. This allows vDSO functions to utilize exception fixup to report unhandled page faults directly to userspace for specific flows in lieu of generating a signal. In the SIGSEGV flow, make sure to call fixup_vdso_exception() after the error code has been sanitized. 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 2ff25ad33233..ff1cb10858d5 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 @@ -928,6 +929,9 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code, if (address >= TASK_SIZE_MAX) error_code |= X86_PF_PROT; + 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); @@ -1045,6 +1049,9 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address, if (is_prefetch(regs, error_code, address)) return; + if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code, address)) + return; + set_signal_archinfo(address, error_code); #ifdef CONFIG_MEMORY_FAILURE -- 2.19.2