From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752357AbZBHFzH (ORCPT ); Sun, 8 Feb 2009 00:55:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752637AbZBHFxq (ORCPT ); Sun, 8 Feb 2009 00:53:46 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.124]:46343 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751924AbZBHFxm (ORCPT ); Sun, 8 Feb 2009 00:53:42 -0500 Message-Id: <20090208055341.467377443@goodmis.org> References: <20090208054955.777429253@goodmis.org> User-Agent: quilt/0.46-1 Date: Sun, 08 Feb 2009 00:50:00 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Thomas Gleixner , Peter Zijlstra , Arnaldo Carvalho de Melo , Frederic Weisbecker , Steven Rostedt Subject: [PATCH 5/8] nmi: add generic nmi tracking state Content-Disposition: inline; filename=0005-nmi-add-generic-nmi-tracking-state.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Rostedt This code adds an in_nmi() macro that uses the current tasks preempt count to track when it is in NMI context. Other parts of the kernel can use this to determine if the context is in NMI context or not. This code was inspired by the -rt patch in_nmi version that was written by Peter Zijlstra, who borrowed that code from Mathieu Desnoyers. Reported-by: Andrew Morton Signed-off-by: Steven Rostedt --- include/linux/hardirq.h | 15 +++++++++++++++ 1 files changed, 15 insertions(+), 0 deletions(-) diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index f832883..f3cf86e 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -61,6 +61,12 @@ #error PREEMPT_ACTIVE is too low! #endif +#define NMI_OFFSET (PREEMPT_ACTIVE << 1) + +#if NMI_OFFSET >= 0x80000000 +#error PREEMPT_ACTIVE too high! +#endif + #define hardirq_count() (preempt_count() & HARDIRQ_MASK) #define softirq_count() (preempt_count() & SOFTIRQ_MASK) #define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK)) @@ -73,6 +79,11 @@ #define in_softirq() (softirq_count()) #define in_interrupt() (irq_count()) +/* + * Are we in NMI context? + */ +#define in_nmi() (preempt_count() & NMI_OFFSET) + #if defined(CONFIG_PREEMPT) # define PREEMPT_INATOMIC_BASE kernel_locked() # define PREEMPT_CHECK_OFFSET 1 @@ -167,6 +178,8 @@ extern void irq_exit(void); #define nmi_enter() \ do { \ ftrace_nmi_enter(); \ + BUG_ON(in_nmi()); \ + add_preempt_count(NMI_OFFSET); \ lockdep_off(); \ rcu_nmi_enter(); \ __irq_enter(); \ @@ -177,6 +190,8 @@ extern void irq_exit(void); __irq_exit(); \ rcu_nmi_exit(); \ lockdep_on(); \ + BUG_ON(!in_nmi()); \ + sub_preempt_count(NMI_OFFSET); \ ftrace_nmi_exit(); \ } while (0) -- 1.5.6.5 --