From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753738AbdKFPCI (ORCPT ); Mon, 6 Nov 2017 10:02:08 -0500 Received: from mail.kernel.org ([198.145.29.99]:35910 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753603AbdKFPCE (ORCPT ); Mon, 6 Nov 2017 10:02:04 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4F92521946 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=frederic@kernel.org From: Frederic Weisbecker To: Ingo Molnar Cc: LKML , Frederic Weisbecker , Tejun Heo , Peter Zijlstra , "David S . Miller" , Lai Jiangshan , Thomas Gleixner , "Paul E . McKenney" Subject: [PATCH 07/14] x86: Use lockdep to assert IRQs are disabled/enabled Date: Mon, 6 Nov 2017 16:01:23 +0100 Message-Id: <1509980490-4285-8-git-send-email-frederic@kernel.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1509980490-4285-1-git-send-email-frederic@kernel.org> References: <1509980490-4285-1-git-send-email-frederic@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use lockdep to check that IRQs are enabled or disabled as expected. This way the sanity check only shows overhead when concurrency correctness debug code is enabled. It also makes no more sense to fix the IRQ flags when a bug is detected as the assertion is now pure config-dependent debugging. And to quote Peter Zijlstra: The whole if !disabled, disable logic is uber paranoid programming, but I don't think we've ever seen that WARN trigger, and if it does (and then burns the kernel) we at least know what happend. Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Paul E. McKenney --- arch/x86/entry/common.c | 4 +--- arch/x86/kernel/smpboot.c | 2 +- 2 files changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index eaa0ba6..d7d3cc2 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -186,9 +186,7 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs) addr_limit_user_check(); - if (IS_ENABLED(CONFIG_PROVE_LOCKING) && WARN_ON(!irqs_disabled())) - local_irq_disable(); - + lockdep_assert_irqs_disabled(); lockdep_sys_exit(); cached_flags = READ_ONCE(ti->flags); diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 198416d..4008b6b 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1095,7 +1095,7 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle) unsigned long flags; int err, ret = 0; - WARN_ON(irqs_disabled()); + lockdep_assert_irqs_enabled(); pr_debug("++++++++++++++++++++=_---CPU UP %u\n", cpu); -- 2.7.4