time: Clean up CLOCK_MONOTONIC_RAW time handling

Now that we fixed the sub-ns handling for CLOCK_MONOTONIC_RAW,
remove the duplicitive tk->raw_time.tv_nsec, which can be
stored in tk->tkr_raw.xtime_nsec (similarly to how its handled
for monotonic time).

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Stephen Boyd <stephen.boyd@linaro.org>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Daniel Mentz <danielmentz@google.com>
Tested-by: Daniel Mentz <danielmentz@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>

3 files changed, 29 insertions, 26 deletions

diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index d0cb007fa482..7492d9009610 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -220,10 +220,8 @@ void update_vsyscall(struct timekeeper *tk)
         if (!use_syscall) {
                 /* tkr_mono.cycle_last == tkr_raw.cycle_last */
                 vdso_data->cs_cycle_last        = tk->tkr_mono.cycle_last;
-                vdso_data->raw_time_sec         = tk->raw_time.tv_sec;
-                vdso_data->raw_time_nsec        = (tk->raw_time.tv_nsec <<
-                                                   tk->tkr_raw.shift) +
-                                                  tk->tkr_raw.xtime_nsec;
+                vdso_data->raw_time_sec         = tk->raw_sec;
+                vdso_data->raw_time_nsec        = tk->tkr_raw.xtime_nsec;
                 vdso_data->xtime_clock_sec      = tk->xtime_sec;
                 vdso_data->xtime_clock_nsec     = tk->tkr_mono.xtime_nsec;
                 vdso_data->cs_mono_mult         = tk->tkr_mono.mult;
diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h
index f7043ccca81c..0a0a53daf2a2 100644
--- a/include/linux/timekeeper_internal.h
+++ b/include/linux/timekeeper_internal.h
@@ -51,7 +51,7 @@ struct tk_read_base {
  * @clock_was_set_seq:  The sequence number of clock was set events
  * @cs_was_changed_seq: The sequence number of clocksource change events
  * @next_leap_ktime:    CLOCK_MONOTONIC time value of a pending leap-second
- * @raw_time:           Monotonic raw base time in timespec64 format
+ * @raw_sec:            CLOCK_MONOTONIC_RAW  time in seconds
  * @cycle_interval:     Number of clock cycles in one NTP interval
  * @xtime_interval:     Number of clock shifted nano seconds in one NTP
  *                      interval.
@@ -93,7 +93,7 @@ struct timekeeper {
         unsigned int            clock_was_set_seq;
         u8                      cs_was_changed_seq;
         ktime_t                 next_leap_ktime;
-        struct timespec64       raw_time;
+        u64                     raw_sec;
 
         /* The following members are for timekeeping internal use */
         u64                     cycle_interval;
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index b602c48cb841..0454bfa24353 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -72,6 +72,10 @@ static inline void tk_normalize_xtime(struct timekeeper *tk)
                 tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
                 tk->xtime_sec++;
         }
+        while (tk->tkr_raw.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_raw.shift)) {
+                tk->tkr_raw.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
+                tk->raw_sec++;
+        }
 }
 
 static inline struct timespec64 tk_xtime(struct timekeeper *tk)
@@ -285,12 +289,14 @@ static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
          /* if changing clocks, convert xtime_nsec shift units */
         if (old_clock) {
                 int shift_change = clock->shift - old_clock->shift;
-                if (shift_change < 0)
+                if (shift_change < 0) {
                         tk->tkr_mono.xtime_nsec >>= -shift_change;
-                else
+                        tk->tkr_raw.xtime_nsec >>= -shift_change;
+                } else {
                         tk->tkr_mono.xtime_nsec <<= shift_change;
+                        tk->tkr_raw.xtime_nsec <<= shift_change;
+                }
         }
-        tk->tkr_raw.xtime_nsec = 0;
 
         tk->tkr_mono.shift = clock->shift;
         tk->tkr_raw.shift = clock->shift;
@@ -619,9 +625,6 @@ static inline void tk_update_ktime_data(struct timekeeper *tk)
         nsec = (u32) tk->wall_to_monotonic.tv_nsec;
         tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
 
-        /* Update the monotonic raw base */
-        tk->tkr_raw.base = timespec64_to_ktime(tk->raw_time);
-
         /*
          * The sum of the nanoseconds portions of xtime and
          * wall_to_monotonic can be greater/equal one second. Take
@@ -631,6 +634,11 @@ static inline void tk_update_ktime_data(struct timekeeper *tk)
         if (nsec >= NSEC_PER_SEC)
                 seconds++;
         tk->ktime_sec = seconds;
+
+        /* Update the monotonic raw base */
+        seconds = tk->raw_sec;
+        nsec = (u32)(tk->tkr_raw.xtime_nsec >> tk->tkr_raw.shift);
+        tk->tkr_raw.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
 }
 
 /* must hold timekeeper_lock */
@@ -672,7 +680,6 @@ static void timekeeping_update(struct timekeeper *tk, unsigned int action)
 static void timekeeping_forward_now(struct timekeeper *tk)
 {
         u64 cycle_now, delta;
-        u64 nsec;
 
         cycle_now = tk_clock_read(&tk->tkr_mono);
         delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
@@ -684,10 +691,13 @@ static void timekeeping_forward_now(struct timekeeper *tk)
         /* If arch requires, add in get_arch_timeoffset() */
         tk->tkr_mono.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_mono.shift;
 
-        tk_normalize_xtime(tk);
 
-        nsec = clocksource_cyc2ns(delta, tk->tkr_raw.mult, tk->tkr_raw.shift);
-        timespec64_add_ns(&tk->raw_time, nsec);
+        tk->tkr_raw.xtime_nsec += delta * tk->tkr_raw.mult;
+
+        /* If arch requires, add in get_arch_timeoffset() */
+        tk->tkr_raw.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_raw.shift;
+
+        tk_normalize_xtime(tk);
 }
 
 /**
@@ -1373,19 +1383,18 @@ int timekeeping_notify(struct clocksource *clock)
 void getrawmonotonic64(struct timespec64 *ts)
 {
         struct timekeeper *tk = &tk_core.timekeeper;
-        struct timespec64 ts64;
         unsigned long seq;
         u64 nsecs;
 
         do {
                 seq = read_seqcount_begin(&tk_core.seq);
+                ts->tv_sec = tk->raw_sec;
                 nsecs = timekeeping_get_ns(&tk->tkr_raw);
-                ts64 = tk->raw_time;
 
         } while (read_seqcount_retry(&tk_core.seq, seq));
 
-        timespec64_add_ns(&ts64, nsecs);
-        *ts = ts64;
+        ts->tv_nsec = 0;
+        timespec64_add_ns(ts, nsecs);
 }
 EXPORT_SYMBOL(getrawmonotonic64);
 
@@ -1509,8 +1518,7 @@ void __init timekeeping_init(void)
         tk_setup_internals(tk, clock);
 
         tk_set_xtime(tk, &now);
-        tk->raw_time.tv_sec = 0;
-        tk->raw_time.tv_nsec = 0;
+        tk->raw_sec = 0;
         if (boot.tv_sec == 0 && boot.tv_nsec == 0)
                 boot = tk_xtime(tk);
 
@@ -2011,15 +2019,12 @@ static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset,
         *clock_set |= accumulate_nsecs_to_secs(tk);
 
         /* Accumulate raw time */
-        tk->tkr_raw.xtime_nsec += (u64)tk->raw_time.tv_nsec << tk->tkr_raw.shift;
         tk->tkr_raw.xtime_nsec += tk->raw_interval << shift;
         snsec_per_sec = (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
         while (tk->tkr_raw.xtime_nsec >= snsec_per_sec) {
                 tk->tkr_raw.xtime_nsec -= snsec_per_sec;
-                tk->raw_time.tv_sec++;
+                tk->raw_sec++;
         }
-        tk->raw_time.tv_nsec = tk->tkr_raw.xtime_nsec >> tk->tkr_raw.shift;
-        tk->tkr_raw.xtime_nsec -= (u64)tk->raw_time.tv_nsec << tk->tkr_raw.shift;
 
         /* Accumulate error between NTP and clock interval */
         tk->ntp_error += tk->ntp_tick << shift;