MIPS: Tracing: Add IRQENTRY_EXIT section for MIPS

This patch add a new section for MIPS to record the block of the hardirq
handling for function graph tracer(print_graph_irq) via adding the
__irq_entry annotation to the the entrypoints of the hardirqs(the block
with irq_enter()...irq_exit()).

Thanks goes to Steven & Frederic Weisbecker for their feedbacks.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nicholas Mc Guire <der.herr@hofr.at>
Cc: zhangfx@lemote.com
Cc: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Patchwork: http://patchwork.linux-mips.org/patch/676/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index e72e684..6cdca19 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -32,6 +32,7 @@
 #include <linux/cpumask.h>
 #include <linux/cpu.h>
 #include <linux/err.h>
+#include <linux/ftrace.h>
 
 #include <asm/atomic.h>
 #include <asm/cpu.h>
@@ -130,7 +131,7 @@
 /*
  * Call into both interrupt handlers, as we share the IPI for them
  */
-void smp_call_function_interrupt(void)
+void __irq_entry smp_call_function_interrupt(void)
 {
 	irq_enter();
 	generic_smp_call_function_single_interrupt();