From 035c038f9cea26404d0d1d2a57ea945fd9911482 Mon Sep 17 00:00:00 2001
From: Steven Rostedt <srostedt@redhat.com>
Date: Fri, 6 Feb 2009 00:51:37 -0500
Subject: [PATCH] --- yaml --- r: 140700 b: refs/heads/master c:
 375b38b4214f29109a393ab762d468054bf52354 h: refs/heads/master v: v3

---
 [refs]                        |  2 +-
 trunk/include/linux/hardirq.h | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 20ca09164b7c..ba8ec3e7cd5b 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4e6ea1440c67de32d7c89aacf233472dfc3bce82
+refs/heads/master: 375b38b4214f29109a393ab762d468054bf52354
diff --git a/trunk/include/linux/hardirq.h b/trunk/include/linux/hardirq.h
index f83288347dda..f3cf86e1465b 100644
--- a/trunk/include/linux/hardirq.h
+++ b/trunk/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)