Merge branch 'fortglx/3.9/time' of git://git.linaro.org/people/jstultz/linux into...

[linux.git] / kernel / time / timekeeping.c

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 4c7de02eacdce9875cefb7598d5047b95f235770..1e35515a875e86966e08a47737c6dfb070956309 100644 (file)
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -21,6 +21,7 @@
 #include <linux/time.h>
 #include <linux/tick.h>
 #include <linux/stop_machine.h>
+#include <linux/pvclock_gtod.h>
 
 
 static struct timekeeper timekeeper;
@@ -28,6 +29,9 @@ static struct timekeeper timekeeper;
 /* flag for if timekeeping is suspended */
 int __read_mostly timekeeping_suspended;
 
+/* Flag for if there is a persistent clock on this platform */
+bool __read_mostly persistent_clock_exist = false;
+
 static inline void tk_normalize_xtime(struct timekeeper *tk)
 {
        while (tk->xtime_nsec >= ((u64)NSEC_PER_SEC << tk->shift)) {
@@ -174,6 +178,54 @@ static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk)
        return nsec + arch_gettimeoffset();
 }
 
+static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
+
+static void update_pvclock_gtod(struct timekeeper *tk)
+{
+       raw_notifier_call_chain(&pvclock_gtod_chain, 0, tk);
+}
+
+/**
+ * pvclock_gtod_register_notifier - register a pvclock timedata update listener
+ *
+ * Must hold write on timekeeper.lock
+ */
+int pvclock_gtod_register_notifier(struct notifier_block *nb)
+{
+       struct timekeeper *tk = &timekeeper;
+       unsigned long flags;
+       int ret;
+
+       write_seqlock_irqsave(&tk->lock, flags);
+       ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
+       /* update timekeeping data */
+       update_pvclock_gtod(tk);
+       write_sequnlock_irqrestore(&tk->lock, flags);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
+
+/**
+ * pvclock_gtod_unregister_notifier - unregister a pvclock
+ * timedata update listener
+ *
+ * Must hold write on timekeeper.lock
+ */
+int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
+{
+       struct timekeeper *tk = &timekeeper;
+       unsigned long flags;
+       int ret;
+
+       write_seqlock_irqsave(&tk->lock, flags);
+       ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
+       write_sequnlock_irqrestore(&tk->lock, flags);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
+
 /* must hold write on timekeeper.lock */
 static void timekeeping_update(struct timekeeper *tk, bool clearntp)
 {
@@ -182,6 +234,7 @@ static void timekeeping_update(struct timekeeper *tk, bool clearntp)
                ntp_clear();
        }
        update_vsyscall(tk);
+       update_pvclock_gtod(tk);
 }
 
 /**
@@ -214,19 +267,18 @@ static void timekeeping_forward_now(struct timekeeper *tk)
 }
 
 /**
- * getnstimeofday - Returns the time of day in a timespec
+ * __getnstimeofday - Returns the time of day in a timespec.
  * @ts:                pointer to the timespec to be set
  *
- * Returns the time of day in a timespec.
+ * Updates the time of day in the timespec.
+ * Returns 0 on success, or -ve when suspended (timespec will be undefined).
  */
-void getnstimeofday(struct timespec *ts)
+int __getnstimeofday(struct timespec *ts)
 {
        struct timekeeper *tk = &timekeeper;
        unsigned long seq;
        s64 nsecs = 0;
 
-       WARN_ON(timekeeping_suspended);
-
        do {
                seq = read_seqbegin(&tk->lock);
 
@@ -237,6 +289,26 @@ void getnstimeofday(struct timespec *ts)
 
        ts->tv_nsec = 0;
        timespec_add_ns(ts, nsecs);
+
+       /*
+        * Do not bail out early, in case there were callers still using
+        * the value, even in the face of the WARN_ON.
+        */
+       if (unlikely(timekeeping_suspended))
+               return -EAGAIN;
+       return 0;
+}
+EXPORT_SYMBOL(__getnstimeofday);
+
+/**
+ * getnstimeofday - Returns the time of day in a timespec.
+ * @ts:                pointer to the timespec to be set
+ *
+ * Returns the time of day in a timespec (WARN if suspended).
+ */
+void getnstimeofday(struct timespec *ts)
+{
+       WARN_ON(__getnstimeofday(ts));
 }
 EXPORT_SYMBOL(getnstimeofday);
 
@@ -590,12 +662,14 @@ void __init timekeeping_init(void)
        struct timespec now, boot, tmp;
 
        read_persistent_clock(&now);
+
        if (!timespec_valid_strict(&now)) {
                pr_warn("WARNING: Persistent clock returned invalid value!\n"
                        "         Check your CMOS/BIOS settings.\n");
                now.tv_sec = 0;
                now.tv_nsec = 0;
-       }
+       } else if (now.tv_sec || now.tv_nsec)
+               persistent_clock_exist = true;
 
        read_boot_clock(&boot);
        if (!timespec_valid_strict(&boot)) {
@@ -668,11 +742,12 @@ void timekeeping_inject_sleeptime(struct timespec *delta)
 {
        struct timekeeper *tk = &timekeeper;
        unsigned long flags;
-       struct timespec ts;
 
-       /* Make sure we don't set the clock twice */
-       read_persistent_clock(&ts);
-       if (!(ts.tv_sec == 0 && ts.tv_nsec == 0))
+       /*
+        * Make sure we don't set the clock twice, as timekeeping_resume()
+        * already did it
+        */
+       if (has_persistent_clock())
                return;
 
        write_seqlock_irqsave(&tk->lock, flags);