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=-6.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 1F598C433DF for ; Thu, 20 Aug 2020 10:54:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE1B320724 for ; Thu, 20 Aug 2020 10:54:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="PBcHfDXy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731783AbgHTKyK (ORCPT ); Thu, 20 Aug 2020 06:54:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41652 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731724AbgHTKxf (ORCPT ); Thu, 20 Aug 2020 06:53:35 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F23BC061387 for ; Thu, 20 Aug 2020 03:53:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=TeO9rz3sjn3E0TMFhE7YmYChuS9nQysvnB1/WdjxhaY=; b=PBcHfDXy4ucnMsPNQgBr3I75z4 0FKlVCqbohuQ2kTGNe8tLI0GVMLTzvw64lc6tq938O1sbVMz6pzP8BKs4bVUm8wCSGpzPJoDiEyd8 rAabX2fGl6+2tua5W56BmFVawBBd6lBwLJkjLLKUQAIzYOxx2cN1syowpDLYUGj9uEdHTGadCssb7 PDt3Oo6AkB4/O0mpETkgeBMjgtEdEDPwBy6ja1SrOb1iZqC7SUfI7kQ/9iTDa5/UCbeh/18gSdALn rcjjzOd7fdSiOkCLQOk+P4FN1fqcuLbw24lQA8jkA8zWX/6+qrl5f6Tv6JGzikWLp9XqJ4QyUMuzs e40NJEPQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1k8iBU-0007Xx-VB; Thu, 20 Aug 2020 10:52:50 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id D62A3306E56; Thu, 20 Aug 2020 12:52:36 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 521EE2C38827F; Thu, 20 Aug 2020 12:52:36 +0200 (CEST) Message-ID: <20200820104905.470593910@infradead.org> User-Agent: quilt/0.66 Date: Thu, 20 Aug 2020 12:38:39 +0200 From: Peter Zijlstra To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Kyle Huey , Alexandre Chartre , Robert O'Callahan , "Paul E. McKenney" , Frederic Weisbecker , Paolo Bonzini , Sean Christopherson , Masami Hiramatsu , Petr Mladek , Steven Rostedt , Joel Fernandes , Boris Ostrovsky , Juergen Gross , Brian Gerst , Andy Lutomirski , Josh Poimboeuf , Peter Zijlstra Subject: [RFC][PATCH 7/7] x86/debug: Move cond_local_irq_enable() block into exc_debug_user() References: <20200820103832.486877479@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/kernel/traps.c | 65 +++++++++++++++++++++++------------------------- 1 file changed, 32 insertions(+), 33 deletions(-) --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -783,41 +783,15 @@ static __always_inline unsigned long deb * * May run on IST stack. */ -static void handle_debug(struct pt_regs *regs, unsigned long dr6) +static bool notify_debug(struct pt_regs *regs, unsigned long dr6) { - struct task_struct *tsk = current; - /* Store the virtualized DR6 value */ - tsk->thread.debugreg6 = dr6; - - if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, 0, - SIGTRAP) == NOTIFY_STOP) { - return; - } - - /* It's safe to allow irq's after DR6 has been saved */ - cond_local_irq_enable(regs); + current->thread.debugreg6 = dr6; - if (v8086_mode(regs)) { - handle_vm86_trap((struct kernel_vm86_regs *) regs, 0, - X86_TRAP_DB); - goto out; - } - - /* - * Reload dr6, the notifier might have changed it. - */ - dr6 = tsk->thread.debugreg6; - /* - * If dr6 has no reason to give us about the origin of this trap, - * then it's very likely the result of an icebp/int01 trap. - * User wants a sigtrap for that. - */ - if (dr6 & (DR_STEP | DR_TRAP_BITS) || !dr6) - send_sigtrap(regs, 0, get_si_code(dr6)); + if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, 0, SIGTRAP) == NOTIFY_STOP) + return true; -out: - cond_local_irq_disable(regs); + return false; } static __always_inline void exc_debug_kernel(struct pt_regs *regs, @@ -872,7 +846,7 @@ static __always_inline void exc_debug_ke if (!dr6) goto out; - handle_debug(regs, dr6); + notify_debug(regs, dr6); out: instrumentation_end(); @@ -902,8 +876,33 @@ static __always_inline void exc_debug_us irqentry_enter_from_user_mode(regs); instrumentation_begin(); - handle_debug(regs, dr6); + if (notify_debug(regs, dr6)) + goto out; + + /* + * Reload dr6, the notifier might have changed it. + */ + dr6 = current->thread.debugreg6; + + /* It's safe to allow irq's after DR6 has been saved */ + local_irq_enable(); + + if (v8086_mode(regs)) { + handle_vm86_trap((struct kernel_vm86_regs *)regs, 0, X86_TRAP_DB); + goto out_irq; + } + /* + * If dr6 has no reason to give us about the origin of this trap, + * then it's very likely the result of an icebp/int01 trap. + * User wants a sigtrap for that. + */ + if (dr6 & (DR_STEP | DR_TRAP_BITS) || !dr6) + send_sigtrap(regs, 0, get_si_code(dr6)); + +out_irq: + local_irq_disable(); +out: instrumentation_end(); irqentry_exit_to_user_mode(regs); }