Merge branch 'linux-linaro-lsk-v4.4' into linux-linaro-lsk-v4.4-android

[firefly-linux-kernel-4.4.55.git] / kernel / time / timekeeping.c

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index d563c19603029bc6c57ac55154f71ed027320276..5fa544f3f560416c3962b88c7cca392f94dac20e 100644 (file)
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -298,12 +298,10 @@ u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
 static inline u32 arch_gettimeoffset(void) { return 0; }
 #endif
 
-static inline s64 timekeeping_get_ns(struct tk_read_base *tkr)
+static inline u64 timekeeping_delta_to_ns(struct tk_read_base *tkr,
+                                         cycle_t delta)
 {
-       cycle_t delta;
-       s64 nsec;
-
-       delta = timekeeping_get_delta(tkr);
+       u64 nsec;
 
        nsec = delta * tkr->mult + tkr->xtime_nsec;
        nsec >>= tkr->shift;
@@ -312,6 +310,24 @@ static inline s64 timekeeping_get_ns(struct tk_read_base *tkr)
        return nsec + arch_gettimeoffset();
 }
 
+static inline s64 timekeeping_get_ns(struct tk_read_base *tkr)
+{
+       cycle_t delta;
+
+       delta = timekeeping_get_delta(tkr);
+       return timekeeping_delta_to_ns(tkr, delta);
+}
+
+static inline s64 timekeeping_cycles_to_ns(struct tk_read_base *tkr,
+                                           cycle_t cycles)
+{
+       cycle_t delta;
+
+       /* calculate the delta since the last update_wall_time */
+       delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
+       return timekeeping_delta_to_ns(tkr, delta);
+}
+
 /**
  * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
  * @tkr: Timekeeping readout base from which we take the update
@@ -384,7 +400,13 @@ static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
        do {
                seq = raw_read_seqcount_latch(&tkf->seq);
                tkr = tkf->base + (seq & 0x01);
-               now = ktime_to_ns(tkr->base) + timekeeping_get_ns(tkr);
+               now = ktime_to_ns(tkr->base);
+
+               now += timekeeping_delta_to_ns(tkr,
+                               clocksource_delta(
+                                       tkr->read(tkr->clock),
+                                       tkr->cycle_last,
+                                       tkr->mask));
        } while (read_seqcount_retry(&tkf->seq, seq));
 
        return now;
@@ -402,6 +424,35 @@ u64 ktime_get_raw_fast_ns(void)
 }
 EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
 
+/**
+ * ktime_get_boot_fast_ns - NMI safe and fast access to boot clock.
+ *
+ * To keep it NMI safe since we're accessing from tracing, we're not using a
+ * separate timekeeper with updates to monotonic clock and boot offset
+ * protected with seqlocks. This has the following minor side effects:
+ *
+ * (1) Its possible that a timestamp be taken after the boot offset is updated
+ * but before the timekeeper is updated. If this happens, the new boot offset
+ * is added to the old timekeeping making the clock appear to update slightly
+ * earlier:
+ *    CPU 0                                        CPU 1
+ *    timekeeping_inject_sleeptime64()
+ *    __timekeeping_inject_sleeptime(tk, delta);
+ *                                                 timestamp();
+ *    timekeeping_update(tk, TK_CLEAR_NTP...);
+ *
+ * (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be
+ * partially updated.  Since the tk->offs_boot update is a rare event, this
+ * should be a rare occurrence which postprocessing should be able to handle.
+ */
+u64 notrace ktime_get_boot_fast_ns(void)
+{
+       struct timekeeper *tk = &tk_core.timekeeper;
+
+       return (ktime_get_mono_fast_ns() + ktime_to_ns(tk->offs_boot));
+}
+EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns);
+
 /* Suspend-time cycles value for halted fast timekeeper. */
 static cycle_t cycles_at_suspend;
 
@@ -959,7 +1010,7 @@ int timekeeping_inject_offset(struct timespec *ts)
        struct timespec64 ts64, tmp;
        int ret = 0;
 
-       if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
+       if (!timespec_inject_offset_valid(ts))
                return -EINVAL;
 
        ts64 = timespec_to_timespec64(*ts);