x86-64: Vclock_gettime(CLOCK_MONOTONIC) can't ever see nsec < 0 (0f51f285) · Commits · 戴 / test

arch/x86/vdso/vclock_gettime.c

+22 −18

Original line number	Diff line number	Diff line
		@@ -55,22 +55,6 @@ notrace static noinline int do_realtime(struct timespec *ts)
		return 0;
		}

		/* Copy of the version in kernel/time.c which we cannot directly access */
		notrace static void
		vset_normalized_timespec(struct timespec *ts, long sec, long nsec)
		{
		while (nsec >= NSEC_PER_SEC) {
		nsec -= NSEC_PER_SEC;
		++sec;
		}
		while (nsec < 0) {
		nsec += NSEC_PER_SEC;
		--sec;
		}
		ts->tv_sec = sec;
		ts->tv_nsec = nsec;
		}

		notrace static noinline int do_monotonic(struct timespec *ts)
		{
		unsigned long seq, ns, secs;
		@@ -81,7 +65,17 @@ notrace static noinline int do_monotonic(struct timespec *ts)
		secs += gtod->wall_to_monotonic.tv_sec;
		ns += gtod->wall_to_monotonic.tv_nsec;
		} while (unlikely(read_seqretry(&gtod->lock, seq)));
		vset_normalized_timespec(ts, secs, ns);

		/* wall_time_nsec, vgetns(), and wall_to_monotonic.tv_nsec
		* are all guaranteed to be nonnegative.
		*/
		while (ns >= NSEC_PER_SEC) {
		ns -= NSEC_PER_SEC;
		++secs;
		}
		ts->tv_sec = secs;
		ts->tv_nsec = ns;

		return 0;
		}

		@@ -106,7 +100,17 @@ notrace static noinline int do_monotonic_coarse(struct timespec *ts)
		secs += gtod->wall_to_monotonic.tv_sec;
		ns += gtod->wall_to_monotonic.tv_nsec;
		} while (unlikely(read_seqretry(&gtod->lock, seq)));
		vset_normalized_timespec(ts, secs, ns);

		/* wall_time_nsec and wall_to_monotonic.tv_nsec are
		* guaranteed to be between 0 and NSEC_PER_SEC.
		*/
		if (ns >= NSEC_PER_SEC) {
		ns -= NSEC_PER_SEC;
		++secs;
		}
		ts->tv_sec = secs;
		ts->tv_nsec = ns;

		return 0;
		}