| Message ID | 20160708132206.2080-1-digetx@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 8 July 2016 at 14:22, Dmitry Osipenko <digetx@gmail.com> wrote: > 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> > --- > hw/core/ptimer.c | 9 ++------- > 1 file changed, 2 insertions(+), 7 deletions(-) > Applied to target-arm.next, thanks. -- PMM
diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c index 05b0c27..30829ee 100644 --- a/hw/core/ptimer.c +++ b/hw/core/ptimer.c @@ -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;
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> --- hw/core/ptimer.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-)