1 files changed, 24 insertions, 3 deletions

diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index 114ae583cca9..50d8b5744cf6 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -3,6 +3,7 @@
 
 #include <linux/preempt.h>
 #include <linux/smp_lock.h>
+#include <linux/lockdep.h>
 #include <asm/hardirq.h>
 #include <asm/system.h>
 
@@ -86,9 +87,6 @@ extern void synchronize_irq(unsigned int irq);
 # define synchronize_irq(irq)   barrier()
 #endif
 
-#define nmi_enter()             irq_enter()
-#define nmi_exit()              sub_preempt_count(HARDIRQ_OFFSET)
-
 struct task_struct;
 
 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
@@ -97,12 +95,35 @@ static inline void account_system_vtime(struct task_struct *tsk)
 }
 #endif
 
+/*
+ * It is safe to do non-atomic ops on ->hardirq_context,
+ * because NMI handlers may not preempt and the ops are
+ * always balanced, so the interrupted value of ->hardirq_context
+ * will always be restored.
+ */
 #define irq_enter()                                     \
         do {                                            \
                 account_system_vtime(current);          \
                 add_preempt_count(HARDIRQ_OFFSET);      \
+                trace_hardirq_enter();                  \
+        } while (0)
+
+/*
+ * Exit irq context without processing softirqs:
+ */
+#define __irq_exit()                                    \
+        do {                                            \
+                trace_hardirq_exit();                   \
+                account_system_vtime(current);          \
+                sub_preempt_count(HARDIRQ_OFFSET);      \
         } while (0)
 
+/*
+ * Exit irq context and process softirqs if needed:
+ */
 extern void irq_exit(void);
 
+#define nmi_enter()             do { lockdep_off(); irq_enter(); } while (0)
+#define nmi_exit()              do { __irq_exit(); lockdep_on(); } while (0)
+
 #endif /* LINUX_HARDIRQ_H */