clocksource: Change __ARCH_HAS_CLOCKSOURCE_DATA to a CONFIG option

The machinery for __ARCH_HAS_CLOCKSOURCE_DATA assumed a file in
asm-generic would be the default for architectures without their own
file in asm/, but that is not how it works.

Replace it with a Kconfig option instead.

Link: http://lkml.kernel.org/r/4E288AA6.7090804@zytor.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@mit.edu>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Tony Luck <tony.luck@intel.com>

arch/ia64/Kconfig

@@ -101,6 +101,9 @@ config GENERIC_IOMAP
 	bool
 	default y
 
+config ARCH_CLOCKSOURCE_DATA
+	def_bool y
+
 config SCHED_OMIT_FRAME_POINTER
 	bool
 	default y

arch/ia64/include/asm/clocksource.h

@@ -3,8 +3,6 @@
 #ifndef _ASM_IA64_CLOCKSOURCE_H
 #define _ASM_IA64_CLOCKSOURCE_H
 
-#define __ARCH_HAS_CLOCKSOURCE_DATA
-
 struct arch_clocksource_data {
 	void *fsys_mmio;        /* used by fsyscall asm code */
 };

arch/x86/Kconfig

@@ -93,6 +93,10 @@ config CLOCKSOURCE_WATCHDOG
 config GENERIC_CLOCKEVENTS
 	def_bool y
 
+config ARCH_CLOCKSOURCE_DATA
+	def_bool y
+	depends on X86_64
+
 config GENERIC_CLOCKEVENTS_BROADCAST
 	def_bool y
 	depends on X86_64 || (X86_32 && X86_LOCAL_APIC)

arch/x86/include/asm/clocksource.h

@@ -5,8 +5,6 @@
 
 #ifdef CONFIG_X86_64
 
-#define __ARCH_HAS_CLOCKSOURCE_DATA
-
 #define VCLOCK_NONE 0  /* No vDSO clock available.	*/
 #define VCLOCK_TSC  1  /* vDSO should use vread_tsc.	*/
 #define VCLOCK_HPET 2  /* vDSO should use vread_hpet.	*/

include/asm-generic/clocksource.h

@@ -1,4 +0,0 @@
-/*
- * Architectures should override this file to add private userspace
- * clock magic if needed.
- */

include/linux/clocksource.h

@@ -22,7 +22,9 @@
 typedef u64 cycle_t;
 struct clocksource;
 
+#ifdef CONFIG_ARCH_CLOCKSOURCE_DATA
 #include <asm/clocksource.h>
+#endif
 
 /**
  * struct cyclecounter - hardware abstraction for a free running counter
@@ -171,7 +173,7 @@ struct clocksource {
 	u32 shift;
 	u64 max_idle_ns;
 
-#ifdef __ARCH_HAS_CLOCKSOURCE_DATA
+#ifdef CONFIG_ARCH_CLOCKSOURCE_DATA
 	struct arch_clocksource_data archdata;
 #endif