[PATCH 1/4] irq: Support to compute context on top of a given preempt_count offset

[Frederic Weisbecker <fweisbec@gmail.com>]

This brings the support to compute irq/preempt contexts on top
of a a given preempt count offset instead of the current one.

This is going to be useful for perf that needs to know the
preempt_count() of the context that an event has interrupted.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
---
 include/linux/hardirq.h |   17 +++++++++++++----
 1 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index d5b3876..0195547 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -58,6 +58,7 @@
 #define SOFTIRQ_MASK	(__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
 #define HARDIRQ_MASK	(__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
 #define NMI_MASK	(__IRQ_MASK(NMI_BITS)     << NMI_SHIFT)
+#define IRQ_MASK	(SOFTIRQ_MASK | HARDIRQ_MASK | NMI_MASK)
 
 #define PREEMPT_OFFSET	(1UL << PREEMPT_SHIFT)
 #define SOFTIRQ_OFFSET	(1UL << SOFTIRQ_SHIFT)
@@ -74,15 +75,23 @@
 #error PREEMPT_ACTIVE is too low!
 #endif
 
-#define hardirq_count()	(preempt_count() & HARDIRQ_MASK)
-#define softirq_count()	(preempt_count() & SOFTIRQ_MASK)
-#define irq_count()	(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
-				 | NMI_MASK))
+#define hardirq_count_offset(offset)	((offset) & HARDIRQ_MASK)
+#define softirq_count_offset(offset)	((offset) & SOFTIRQ_MASK)
+#define irq_count_offset(offset)	((offset) & IRQ_MASK)
+
+#define hardirq_count()			hardirq_count_offset(preempt_count())
+#define softirq_count()			softirq_count_offset(preempt_count())
+#define irq_count()			irq_count_offset(preempt_count())
 
 /*
  * Are we doing bottom half or hardware interrupt processing?
  * Are we in a softirq context? Interrupt context?
  */
+#define in_irq_offset(offset)		(hardirq_count_offset(offset))
+#define in_softirq_offset(offset)	(softirq_count_offset(offset))
+#define in_interrupt_offset(offset)	(irq_count_offset(offset))
+
+
 #define in_irq()		(hardirq_count())
 #define in_softirq()		(softirq_count())
 #define in_interrupt()		(irq_count())
-- 
1.6.2.3