Commit 56215da3 authored by Dmitry Osipenko's avatar Dmitry Osipenko Committed by Peter Maydell
Browse files

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 5a50307b ("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: default avatarDmitry Osipenko <digetx@gmail.com>
Message-id: 20160708132206.2080-1-digetx@gmail.com
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parent f58b39d2

hw/core/ptimer.c

+2 −7
Original line number Diff line number Diff line
@@ -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;