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>

1 files changed, 14 insertions, 7 deletions

diff --git a/arch/mips/kernel/smtc.c b/arch/mips/kernel/smtc.c
index a38e3ee95515..23499b5bd9c3 100644
--- a/arch/mips/kernel/smtc.c
+++ b/arch/mips/kernel/smtc.c
@@ -25,6 +25,7 @@
 #include <linux/interrupt.h>
 #include <linux/kernel_stat.h>
 #include <linux/module.h>
+#include <linux/ftrace.h>
 
 #include <asm/cpu.h>
 #include <asm/processor.h>
@@ -939,23 +940,29 @@ static void ipi_call_interrupt(void)
 
 DECLARE_PER_CPU(struct clock_event_device, mips_clockevent_device);
 
-void ipi_decode(struct smtc_ipi *pipi)
+static void __irq_entry smtc_clock_tick_interrupt(void)
 {
         unsigned int cpu = smp_processor_id();
         struct clock_event_device *cd;
+        int irq = MIPS_CPU_IRQ_BASE + 1;
+
+        irq_enter();
+        kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq));
+        cd = &per_cpu(mips_clockevent_device, cpu);
+        cd->event_handler(cd);
+        irq_exit();
+}
+
+void ipi_decode(struct smtc_ipi *pipi)
+{
         void *arg_copy = pipi->arg;
         int type_copy = pipi->type;
-        int irq = MIPS_CPU_IRQ_BASE + 1;
 
         smtc_ipi_nq(&freeIPIq, pipi);
 
         switch (type_copy) {
         case SMTC_CLOCK_TICK:
-                irq_enter();
-                kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq));
-                cd = &per_cpu(mips_clockevent_device, cpu);
-                cd->event_handler(cd);
-                irq_exit();
+                smtc_clock_tick_interrupt();
                 break;
 
         case LINUX_SMP_IPI: