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=-6.8 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 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 59873C433E7 for ; Wed, 2 Sep 2020 15:00:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2C53A20773 for ; Wed, 2 Sep 2020 15:00:46 +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="Ac/StFTH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728087AbgIBPAo (ORCPT ); Wed, 2 Sep 2020 11:00:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34094 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727827AbgIBNrT (ORCPT ); Wed, 2 Sep 2020 09:47:19 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AB011C061265 for ; Wed, 2 Sep 2020 06:38:44 -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=oUkO7fX2WCJTU4/pYB1x6qlwNwBzlfvqwzYit8QR3ZE=; b=Ac/StFTHcxsphW55isgA1FXYdM uGJxTyLq4lGOQbFFZ1LtN5RxL9ZSMqe395GboHzGvAHqScbjYUJbzxpRUpXSOuk9Cy0E/8jFk0rfD n0odnqUemQOkr3Z0fPWQIPVT3ht6xWvWVsHu604SCarT4v44VM6WPnBsPIGkTtwWM2FwDDLAoPER0 S+IKT6kIun/Ok26n3AfLMc324KKz3HM26kYil3BOC3g6pn1Qthzx8raLKACF8INOga/Y0SrYLmqXe qxOOyX8Ub/D8fxWhU5XgK91Eq16kuNt47paiPW8ohqTMAz80lBhjJIBVNKguf5rAqhMy/8h6/6gXy 155ejiOg==; 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 1kDSxr-0003Zd-9o; Wed, 02 Sep 2020 13:38:15 +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 A057A3075F1; Wed, 2 Sep 2020 15:38:12 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id D26B529A82C25; Wed, 2 Sep 2020 15:38:11 +0200 (CEST) Message-ID: <20200902133201.094265982@infradead.org> User-Agent: quilt/0.66 Date: Wed, 02 Sep 2020 15:25:57 +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 , Daniel Thompson , Peter Zijlstra Subject: [PATCH 08/13] x86/debug: Move cond_local_irq_enable() block into exc_debug_user() References: <20200902132549.496605622@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 The cond_local_irq_enable() block, dealing with vm86 and sending signals is only relevant for #DB-from-user, move it there. This then reduces handle_debug() to only the notifier call, so rename it to notify_debug(). Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/kernel/traps.c | 58 ++++++++++++++++++++++++------------------------ 1 file changed, 29 insertions(+), 29 deletions(-) --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -783,17 +783,10 @@ static __always_inline unsigned long deb * * May run on IST stack. */ -static bool 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; - bool icebp; - - /* - * 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. - */ - icebp = !*dr6; /* Store the virtualized DR6 value */ tsk->thread.debugreg6 = *dr6; @@ -801,26 +794,9 @@ static bool handle_debug(struct pt_regs if (notify_die(DIE_DEBUG, "debug", regs, (long)dr6, 0, SIGTRAP) == NOTIFY_STOP) return true; - /* It's safe to allow irq's after DR6 has been saved */ - cond_local_irq_enable(regs); - - 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. - */ + /* Reload the DR6 value, the notifier might have changed it */ *dr6 = tsk->thread.debugreg6; - if (*dr6 & (DR_STEP | DR_TRAP_BITS) || icebp) - send_sigtrap(regs, 0, get_si_code(*dr6)); - -out: - cond_local_irq_disable(regs); - return false; } @@ -864,7 +840,7 @@ static __always_inline void exc_debug_ke if (!dr6) goto out; - if (handle_debug(regs, &dr6)) + if (notify_debug(regs, &dr6)) goto out; if (WARN_ON_ONCE(dr6 & DR_STEP)) { @@ -889,6 +865,8 @@ static __always_inline void exc_debug_ke static __always_inline void exc_debug_user(struct pt_regs *regs, unsigned long dr6) { + bool icebp; + /* * If something gets miswired and we end up here for a kernel mode * #DB, we will malfunction. @@ -907,8 +885,30 @@ static __always_inline void exc_debug_us irqentry_enter_from_user_mode(regs); instrumentation_begin(); - handle_debug(regs, &dr6); + /* + * 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. + */ + icebp = !dr6; + if (notify_debug(regs, &dr6)) + goto out; + + /* 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 & (DR_STEP | DR_TRAP_BITS) || icebp) + send_sigtrap(regs, 0, get_si_code(dr6)); + +out_irq: + local_irq_disable(); +out: instrumentation_end(); irqentry_exit_to_user_mode(regs); }