From: john stultz <johnstul@us.ibm.com>
Date: Fri, 16 Feb 2007 09:28:17 +0000 (-0800)
Subject: [PATCH] generic: vsyscall-gtod support for GENERIC_TIME
X-Git-Tag: v2.6.21-rc1~118
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=acc9a9dcdd0dd1d295c2f2ee02c27c761bd63cb1;p=linux-2.6

[PATCH] generic: vsyscall-gtod support for GENERIC_TIME

Provides generic infrastructure for vsyscall-gtod.

[akpm@osdl.org: cleanup]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Roman Zippel <zippel@linux-m68k.org>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 830a250ecf..daa4940cc0 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -47,6 +47,7 @@ struct clocksource;
  * @mult:		cycle to nanosecond multiplier
  * @shift:		cycle to nanosecond divisor (power of two)
  * @flags:		flags describing special properties
+ * @vread:		vsyscall based read
  * @cycle_interval:	Used internally by timekeeping core, please ignore.
  * @xtime_interval:	Used internally by timekeeping core, please ignore.
  */
@@ -59,6 +60,7 @@ struct clocksource {
 	u32 mult;
 	u32 shift;
 	unsigned long flags;
+	cycle_t (*vread)(void);
 
 	/* timekeeping specific data, ignore */
 	cycle_t cycle_last, cycle_interval;
@@ -197,4 +199,12 @@ extern int clocksource_register(struct clocksource*);
 extern struct clocksource* clocksource_get_next(void);
 extern void clocksource_change_rating(struct clocksource *cs, int rating);
 
+#ifdef CONFIG_GENERIC_TIME_VSYSCALL
+extern void update_vsyscall(struct timespec *ts, struct clocksource *c);
+#else
+static inline void update_vsyscall(struct timespec *ts, struct clocksource *c)
+{
+}
+#endif
+
 #endif /* _LINUX_CLOCKSOURCE_H */
diff --git a/kernel/timer.c b/kernel/timer.c
index c3c67f3c01..cb1b86a9c5 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1174,6 +1174,7 @@ static void update_wall_time(void)
 
 	/* check to see if there is a new clocksource to use */
 	change_clocksource();
+	update_vsyscall(&xtime, clock);
 }
 
 /*