clockevents: Allow build w/o run-tine usage for migration purposes

Migration aid to allow preparatory patches which introduce not yet
used parts of clock events code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>

4 files changed, 14 insertions, 4 deletions

diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
index f368a6fe8cc9..d2ddea926895 100644
--- a/include/linux/clockchips.h
+++ b/include/linux/clockchips.h
@@ -8,7 +8,7 @@
 #ifndef _LINUX_CLOCKCHIPS_H
 #define _LINUX_CLOCKCHIPS_H
 
-#ifdef CONFIG_GENERIC_CLOCKEVENTS
+#ifdef CONFIG_GENERIC_CLOCKEVENTS_BUILD
 
 #include <linux/clocksource.h>
 #include <linux/cpumask.h>
@@ -126,9 +126,13 @@ extern int clockevents_register_notifier(struct notifier_block *nb);
 extern int clockevents_program_event(struct clock_event_device *dev,
                                      ktime_t expires, ktime_t now);
 
+#ifdef CONFIG_GENERIC_CLOCKEVENTS
 extern void clockevents_notify(unsigned long reason, void *arg);
-
 #else
+# define clockevents_notify(reason, arg) do { } while (0)
+#endif
+
+#else /* CONFIG_GENERIC_CLOCKEVENTS_BUILD */
 
 #define clockevents_notify(reason, arg) do { } while (0)
 
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index f66351126544..8d53106a0a92 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -23,3 +23,8 @@ config HIGH_RES_TIMERS
           hardware is not capable then this option only increases
           the size of the kernel image.
 
+config GENERIC_CLOCKEVENTS_BUILD
+        bool
+        default y
+        depends on GENERIC_CLOCKEVENTS || GENERIC_CLOCKEVENTS_MIGR
+
diff --git a/kernel/time/Makefile b/kernel/time/Makefile
index 99b6034fc86b..905b0b50792d 100644
--- a/kernel/time/Makefile
+++ b/kernel/time/Makefile
@@ -1,6 +1,6 @@
 obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o
 
-obj-$(CONFIG_GENERIC_CLOCKEVENTS)               += clockevents.o
+obj-$(CONFIG_GENERIC_CLOCKEVENTS_BUILD)         += clockevents.o
 obj-$(CONFIG_GENERIC_CLOCKEVENTS)               += tick-common.o
 obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)     += tick-broadcast.o
 obj-$(CONFIG_TICK_ONESHOT)                      += tick-oneshot.o
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 41dd3105ce7f..822beebe664a 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -194,6 +194,7 @@ void clockevents_exchange_device(struct clock_event_device *old,
         local_irq_restore(flags);
 }
 
+#ifdef CONFIG_GENERIC_CLOCKEVENTS
 /**
  * clockevents_notify - notification about relevant events
  */
@@ -222,4 +223,4 @@ void clockevents_notify(unsigned long reason, void *arg)
         spin_unlock(&clockevents_lock);
 }
 EXPORT_SYMBOL_GPL(clockevents_notify);
-
+#endif