time: Introduce new GENERIC_TIME_VSYSCALL

Now that we moved everyone over to GENERIC_TIME_VSYSCALL_OLD,
introduce the new declaration and config option for the new
update_vsyscall method.

Cc: Tony Luck <tony.luck@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>

3 files changed, 34 insertions, 20 deletions

diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h
index a904d76a5fa..e1d558e237e 100644
--- a/include/linux/timekeeper_internal.h
+++ b/include/linux/timekeeper_internal.h
@@ -66,16 +66,38 @@ struct timekeeper {
         seqlock_t               lock;
 };
 
+static inline struct timespec tk_xtime(struct timekeeper *tk)
+{
+        struct timespec ts;
+
+        ts.tv_sec = tk->xtime_sec;
+        ts.tv_nsec = (long)(tk->xtime_nsec >> tk->shift);
+        return ts;
+}
+
+
+#ifdef CONFIG_GENERIC_TIME_VSYSCALL
+
+extern void update_vsyscall(struct timekeeper *tk);
+extern void update_vsyscall_tz(void);
 
-#ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
-extern void
-update_vsyscall_old(struct timespec *ts, struct timespec *wtm,
-                        struct clocksource *c, u32 mult);
+#elif defined(CONFIG_GENERIC_TIME_VSYSCALL_OLD)
+
+extern void update_vsyscall_old(struct timespec *ts, struct timespec *wtm,
+                                struct clocksource *c, u32 mult);
 extern void update_vsyscall_tz(void);
+
+static inline void update_vsyscall(struct timekeeper *tk)
+{
+        struct timespec xt;
+
+        xt = tk_xtime(tk);
+        update_vsyscall_old(&xt, &tk->wall_to_monotonic, tk->clock, tk->mult);
+}
+
 #else
-static inline void
-update_vsyscall_old(struct timespec *ts, struct timespec *wtm,
-                                        struct clocksource *c, u32 mult)
+
+static inline void update_vsyscall(struct timekeeper *tk)
 {
 }
 static inline void update_vsyscall_tz(void)
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 489c86154d1..8601f0db126 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -13,6 +13,10 @@ config ARCH_CLOCKSOURCE_DATA
         bool
 
 # Timekeeping vsyscall support
+config GENERIC_TIME_VSYSCALL
+        bool
+
+# Timekeeping vsyscall support
 config GENERIC_TIME_VSYSCALL_OLD
         bool
 
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 7c2851384c4..ce618010c37 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -42,15 +42,6 @@ static inline void tk_normalize_xtime(struct timekeeper *tk)
         }
 }
 
-static struct timespec tk_xtime(struct timekeeper *tk)
-{
-        struct timespec ts;
-
-        ts.tv_sec = tk->xtime_sec;
-        ts.tv_nsec = (long)(tk->xtime_nsec >> tk->shift);
-        return ts;
-}
-
 static void tk_set_xtime(struct timekeeper *tk, const struct timespec *ts)
 {
         tk->xtime_sec = ts->tv_sec;
@@ -192,14 +183,11 @@ static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk)
 /* must hold write on timekeeper.lock */
 static void timekeeping_update(struct timekeeper *tk, bool clearntp)
 {
-        struct timespec xt;
-
         if (clearntp) {
                 tk->ntp_error = 0;
                 ntp_clear();
         }
-        xt = tk_xtime(tk);
-        update_vsyscall_old(&xt, &tk->wall_to_monotonic, tk->clock, tk->mult);
+        update_vsyscall(tk);
 }
 
 /**