From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40803) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bsjoI-00088P-57 for qemu-devel@nongnu.org; Sat, 08 Oct 2016 01:04:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bsjoG-0003Cp-0O for qemu-devel@nongnu.org; Sat, 08 Oct 2016 01:04:33 -0400 From: P J P Date: Sat, 8 Oct 2016 10:34:18 +0530 Message-Id: <1475903058-729-1-git-send-email-ppandit@redhat.com> Subject: [Qemu-devel] [PATCH v4] timer: a9gtimer: remove loop to auto-increment comparator List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Qemu Developers Cc: Peter Maydell , Li Qiang , qemu-arm@nongnu.org, Prasad J Pandit From: Prasad J Pandit 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 Signed-off-by: Prasad J Pandit --- 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