[PATCH] lockdep: irqtrace subsystem, core
Accurate hard-IRQ-flags and softirq-flags state tracing.
This allows us to attach extra functionality to IRQ flags on/off
events (such as trace-on/off).
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index 114ae58..b1d4332 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -86,9 +86,6 @@
# 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 +94,35 @@
}
#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() irq_enter()
+#define nmi_exit() __irq_exit()
+
#endif /* LINUX_HARDIRQ_H */
