From: Prasad J Pandit <p...@fedoraproject.org> ARM A9MP processor has a peripheral timer with an auto-increment register, which holds an increment step value. A user could set this value to zero. When auto-increment control bit is enabled, it leads to an infinite loop in 'a9_gtimer_update' while updating comparator value. Remove this loop incrementing the comparator value.
Reported-by: Li Qiang <liqiang...@360.cn> Signed-off-by: Prasad J Pandit <p...@fedoraproject.org> --- hw/timer/a9gtimer.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) Update per -> https://lists.gnu.org/archive/html/qemu-devel/2016-10/msg01393.html diff --git a/hw/timer/a9gtimer.c b/hw/timer/a9gtimer.c index 772f85f..02092dd 100644 --- a/hw/timer/a9gtimer.c +++ b/hw/timer/a9gtimer.c @@ -73,6 +73,7 @@ static void a9_gtimer_update(A9GTimerState *s, bool sync) A9GTimerUpdate update = a9_gtimer_get_update(s); int i; + uint64_t inc; int64_t next_cdiff = 0; for (i = 0; i < s->num_cpu; ++i) { @@ -82,15 +83,15 @@ static void a9_gtimer_update(A9GTimerState *s, bool sync) if ((s->control & R_CONTROL_TIMER_ENABLE) && (gtb->control & R_CONTROL_COMP_ENABLE)) { /* R2p0+, where the compare function is >= */ - while (gtb->compare < update.new) { + if (gtb->compare < update.new) { DB_PRINT("Compare event happened for CPU %d\n", i); gtb->status = 1; - if (gtb->control & R_CONTROL_AUTO_INCREMENT) { - DB_PRINT("Auto incrementing timer compare by %" PRId32 "\n", - gtb->inc); - gtb->compare += gtb->inc; - } else { - break; + if (gtb->control & R_CONTROL_AUTO_INCREMENT && gtb->inc) { + inc = update.new - gtb->compare - 1; + inc = QEMU_ALIGN_DOWN(inc, gtb->inc); + DB_PRINT("Auto incrementing timer compare by %" + PRId64 "\n", inc); + gtb->compare += inc; } } cdiff = (int64_t)gtb->compare - (int64_t)update.new + 1; -- 2.5.5
