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-rw-r--r--kernel/time/timekeeping.c31
1 files changed, 27 insertions, 4 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 21cc239..34b4ced 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1604,9 +1604,12 @@ static __always_inline void timekeeping_freqadjust(struct timekeeper *tk,
{
s64 interval = tk->cycle_interval;
s64 xinterval = tk->xtime_interval;
+ u32 base = tk->tkr_mono.clock->mult;
+ u32 max = tk->tkr_mono.clock->maxadj;
+ u32 cur_adj = tk->tkr_mono.mult;
s64 tick_error;
bool negative;
- u32 adj;
+ u32 adj_scale;
/* Remove any current error adj from freq calculation */
if (tk->ntp_err_mult)
@@ -1625,13 +1628,33 @@ static __always_inline void timekeeping_freqadjust(struct timekeeper *tk,
/* preserve the direction of correction */
negative = (tick_error < 0);
- /* Sort out the magnitude of the correction */
+ /* If any adjustment would pass the max, just return */
+ if (negative && (cur_adj - 1) <= (base - max))
+ return;
+ if (!negative && (cur_adj + 1) >= (base + max))
+ return;
+ /*
+ * Sort out the magnitude of the correction, but
+ * avoid making so large a correction that we go
+ * over the max adjustment.
+ */
+ adj_scale = 0;
tick_error = abs(tick_error);
- for (adj = 0; tick_error > interval; adj++)
+ while (tick_error > interval) {
+ u32 adj = 1 << (adj_scale + 1);
+
+ /* Check if adjustment gets us within 1 unit from the max */
+ if (negative && (cur_adj - adj) <= (base - max))
+ break;
+ if (!negative && (cur_adj + adj) >= (base + max))
+ break;
+
+ adj_scale++;
tick_error >>= 1;
+ }
/* scale the corrections */
- timekeeping_apply_adjustment(tk, offset, negative, adj);
+ timekeeping_apply_adjustment(tk, offset, negative, adj_scale);
}
/*
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