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 1CD3CC04EBF for ; Wed, 5 Dec 2018 23:20:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DEACB205C9 for ; Wed, 5 Dec 2018 23:20:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DEACB205C9 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 S1728861AbeLEXUc (ORCPT ); Wed, 5 Dec 2018 18:20:32 -0500 Received: from mga06.intel.com ([134.134.136.31]:24299 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728841AbeLEXUa (ORCPT ); Wed, 5 Dec 2018 18:20:30 -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="281279558" 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 3/4] x86/traps: Attempt to fixup exceptions in vDSO before signaling Date: Wed, 5 Dec 2018 15:20:11 -0800 Message-Id: <20181205232012.28920-4-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() to attempt to fixup exceptions in vDSO code before generating a signal for userspace faults. This allows vDSO functions to utilize exception fixup to report unhandled exceptions directly to userspace for specific flows in lieu of generating a signal. Suggested-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Jarkko Sakkinen Cc: Dave Hansen Cc: Josh Triplett Signed-off-by: Sean Christopherson --- arch/x86/kernel/traps.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 9b7c4ca8f0a7..106a6cc20ad6 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -61,6 +61,7 @@ #include #include #include +#include #ifdef CONFIG_X86_64 #include @@ -223,6 +224,10 @@ do_trap_no_signal(struct task_struct *tsk, int trapnr, const char *str, tsk->thread.error_code = error_code; tsk->thread.trap_nr = trapnr; + if (user_mode(regs) && + fixup_vdso_exception(regs, trapnr, error_code, 0)) + return 0; + return -1; } @@ -563,6 +568,9 @@ do_general_protection(struct pt_regs *regs, long error_code) tsk->thread.error_code = error_code; tsk->thread.trap_nr = X86_TRAP_GP; + if (fixup_vdso_exception(regs, X86_TRAP_GP, error_code, 0)) + return; + show_signal(tsk, SIGSEGV, "", desc, regs, error_code); force_sig(SIGSEGV, tsk); @@ -854,6 +862,9 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr) if (!si_code) return; + if (fixup_vdso_exception(regs, trapnr, error_code, 0)) + return; + force_sig_fault(SIGFPE, si_code, (void __user *)uprobe_get_trap_addr(regs), task); } -- 2.19.2