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=-3.8 required=3.0 tests=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 8461CC10DCE for ; Sun, 8 Mar 2020 23:25:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 54E5120863 for ; Sun, 8 Mar 2020 23:25:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727326AbgCHXZb (ORCPT ); Sun, 8 Mar 2020 19:25:31 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:57260 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726640AbgCHXX5 (ORCPT ); Sun, 8 Mar 2020 19:23:57 -0400 Received: from p5de0bf0b.dip0.t-ipconnect.de ([93.224.191.11] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jB5Gl-00036r-Pt; Mon, 09 Mar 2020 00:23:41 +0100 Received: from nanos.tec.linutronix.de (localhost [IPv6:::1]) by nanos.tec.linutronix.de (Postfix) with ESMTP id E657E1040B5; Mon, 9 Mar 2020 00:23:30 +0100 (CET) Message-Id: <20200308222610.245444311@linutronix.de> User-Agent: quilt/0.65 Date: Sun, 08 Mar 2020 23:24:12 +0100 From: Thomas Gleixner To: LKML Cc: x86@kernel.org, Steven Rostedt , Brian Gerst , Juergen Gross , Frederic Weisbecker , Alexandre Chartre Subject: [patch part-II V2 13/13] x86/entry/common: Split irq tracing in prepare_exit_to_usermode() References: <20200308222359.370649591@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As in entry from user mode, lockdep and tracing have different requirements. lockdep needs to know about the interrupts off state accross the call to user_enter_irqsoff() but tracing is unsafe after the call. Split it up and tell the tracer that interrupts are going to be enabled before calling user_enter_irqsoff() and tell lockdep afterwards. Signed-off-by: Thomas Gleixner --- arch/x86/entry/common.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -251,9 +251,19 @@ static noinline void __prepare_exit_to_u { __prepare_exit_to_usermode(regs); + /* + * Return to user space enables interrupts. Tell the tracer before + * invoking user_enter_irqsoff() which switches to CONTEXT_USER and + * RCU to rcuidle state. Lockdep still needs to keep the irqs + * disabled state. + */ + __trace_hardirqs_on(); + user_enter_irqoff(); mds_user_clear_cpu_buffers(); - trace_hardirqs_on(); + + /* All done. Tell lockdep as well. */ + lockdep_hardirqs_on(CALLER_ADDR0); } NOKPROBE_SYMBOL(prepare_exit_to_usermode);