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-rw-r--r--kernel/posix-cpu-timers.c2
-rw-r--r--kernel/time/timekeeping.c22
2 files changed, 23 insertions, 1 deletions
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 895337b16a24..4e5288a831de 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -311,7 +311,7 @@ static int cpu_clock_sample_group(const clockid_t which_clock,
311 struct task_cputime cputime; 311 struct task_cputime cputime;
312 312
313 thread_group_cputime(p, &cputime); 313 thread_group_cputime(p, &cputime);
314 switch (which_clock) { 314 switch (CPUCLOCK_WHICH(which_clock)) {
315 default: 315 default:
316 return -EINVAL; 316 return -EINVAL;
317 case CPUCLOCK_PROF: 317 case CPUCLOCK_PROF:
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index e7acfb482a68..fa05e88aa76f 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -518,6 +518,28 @@ void update_wall_time(void)
518 /* correct the clock when NTP error is too big */ 518 /* correct the clock when NTP error is too big */
519 clocksource_adjust(offset); 519 clocksource_adjust(offset);
520 520
521 /*
522 * Since in the loop above, we accumulate any amount of time
523 * in xtime_nsec over a second into xtime.tv_sec, its possible for
524 * xtime_nsec to be fairly small after the loop. Further, if we're
525 * slightly speeding the clocksource up in clocksource_adjust(),
526 * its possible the required corrective factor to xtime_nsec could
527 * cause it to underflow.
528 *
529 * Now, we cannot simply roll the accumulated second back, since
530 * the NTP subsystem has been notified via second_overflow. So
531 * instead we push xtime_nsec forward by the amount we underflowed,
532 * and add that amount into the error.
533 *
534 * We'll correct this error next time through this function, when
535 * xtime_nsec is not as small.
536 */
537 if (unlikely((s64)clock->xtime_nsec < 0)) {
538 s64 neg = -(s64)clock->xtime_nsec;
539 clock->xtime_nsec = 0;
540 clock->error += neg << (NTP_SCALE_SHIFT - clock->shift);
541 }
542
521 /* store full nanoseconds into xtime after rounding it up and 543 /* store full nanoseconds into xtime after rounding it up and
522 * add the remainder to the error difference. 544 * add the remainder to the error difference.
523 */ 545 */