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 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 DC37AC433E1 for ; Fri, 21 Aug 2020 10:21:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B3B3A20732 for ; Fri, 21 Aug 2020 10:21:56 +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="gksTdrf1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728607AbgHUKVy (ORCPT ); Fri, 21 Aug 2020 06:21:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33944 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728595AbgHUKVt (ORCPT ); Fri, 21 Aug 2020 06:21:49 -0400 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8680EC061385 for ; Fri, 21 Aug 2020 03:21:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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=1KthyYVeQG1Z3bnv0wlVVPWU8hBkSXSEYySbte/Kc5k=; b=gksTdrf1eVCOxQMJkS4ma+Mb13 b/KJFUpWrOCg8G0SF4/Sd2aL6+/WNTaViL87MoOsKKJ7scGbXlsG3igcVy23ZPh79gvTb+/keQL9k V5nCSqQghaNBXd/oJF52CjlfMeXmuz24r4R+Vcq7H5yoGmNIElymytltsxFTwly62AuSWLFiAuQDU LW7KA5wQ+RGmlGczlijaelFGXDQStnBB1gt7jro5+nDduSgxNX19FPlo0+eNrTRJk7sJqnu0GLbZk 8N0HvP+oju6/hr4u/RYcyYuJO8Or7xn8hRRks/npMuA6VORcda99mISuJ74A5jCNk8HbSCCzkHg5A fQBVjc+Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1k94An-0008GP-Rp; Fri, 21 Aug 2020 10:21:26 +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 6CB09305815; Fri, 21 Aug 2020 12:21:24 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 579552C8FF367; Fri, 21 Aug 2020 12:21:24 +0200 (CEST) Message-ID: <20200821102052.910320981@infradead.org> User-Agent: quilt/0.66 Date: Fri, 21 Aug 2020 11:39:15 +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 v2 3/8] x86/debug: Move kprobe_debug_handler() into exc_debug_kernel() References: <20200821093912.815135402@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 Kprobes are on kernel text, and thus only matter for #DB-from-kernel. Kprobes are ordered before the generic notifier, preserve that order. Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/include/asm/kprobes.h | 4 ++++ arch/x86/kernel/traps.c | 10 ++++------ 2 files changed, 8 insertions(+), 6 deletions(-) --- a/arch/x86/include/asm/kprobes.h +++ b/arch/x86/include/asm/kprobes.h @@ -106,5 +106,9 @@ extern int kprobe_exceptions_notify(stru extern int kprobe_int3_handler(struct pt_regs *regs); extern int kprobe_debug_handler(struct pt_regs *regs); +#else + +static inline int kprobe_debug_handler(struct pt_regs *regs) { return 0; } + #endif /* CONFIG_KPROBES */ #endif /* _ASM_X86_KPROBES_H */ --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -806,12 +806,6 @@ static void handle_debug(struct pt_regs /* Store the virtualized DR6 value */ tsk->thread.debugreg6 = dr6; -#ifdef CONFIG_KPROBES - if (kprobe_debug_handler(regs)) { - return; - } -#endif - if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, 0, SIGTRAP) == NOTIFY_STOP) { return; @@ -877,8 +871,12 @@ static __always_inline void exc_debug_ke if ((dr6 & DR_STEP) && is_sysenter_singlestep(regs)) dr6 &= ~DR_STEP; + if (kprobe_debug_handler(regs)) + goto out; + handle_debug(regs, dr6, false); +out: instrumentation_end(); idtentry_exit_nmi(regs, irq_state);