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Revert "hw/ptimer: Perform counter wrap around if timer already expired" 

Software should see timer counter wraparound only after IRQ being triggered.
This fixes regression introduced by the commit 5a50307 ("hw/ptimer: Perform
counter wrap around if timer already expired"), resulting in monotonic timer
jumping backwards on SPARC emulated machine running NetBSD guest OS, as
reported by Mark Cave-Ayland.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Message-id: 20160708132206.2080-1-digetx@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Dmitry Osipenko 2016-07-14 16:51:36 +01:00 committed by Peter Maydell
parent f58b39d2d5
commit 56215da394
1 changed files with 2 additions and 7 deletions
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9
hw/core/ptimer.c
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@ -93,7 +93,7 @@ uint64_t ptimer_get_count(ptimer_state *s)
bool oneshot = (s->enabled == 2);
/* Figure out the current counter value. */
if (s->period == 0 || (expired && (oneshot || use_icount))) {
if (expired) {
/* Prevent timer underflowing if it should already have
triggered. */
counter = 0;
@ -120,7 +120,7 @@ uint64_t ptimer_get_count(ptimer_state *s)
backwards.
*/
rem = expired ? now - next : next - now;
rem = next - now;
div = period;
clz1 = clz64(rem);
@ -140,11 +140,6 @@ uint64_t ptimer_get_count(ptimer_state *s)
div += 1;
}
counter = rem / div;
if (expired && counter != 0) {
/* Wrap around periodic counter. */
counter = s->limit - (counter - 1) % s->limit;
}
}
} else {
counter = s->delta;