From patchwork Sat Oct 8 05:04:18 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Prasad Pandit X-Patchwork-Id: 9367997 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 884D56077E for ; Sat, 8 Oct 2016 05:04:55 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6640A297C8 for ; Sat, 8 Oct 2016 05:04:55 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 58C0E2989C; Sat, 8 Oct 2016 05:04:55 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 27A04297C8 for ; Sat, 8 Oct 2016 05:04:53 +0000 (UTC) Received: from localhost ([::1]:39321 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bsjoZ-0008AX-Cr for patchwork-qemu-devel@patchwork.kernel.org; Sat, 08 Oct 2016 01:04:51 -0400 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 Received: from mx1.redhat.com ([209.132.183.28]:48452) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bsjoB-0003AF-E7; Sat, 08 Oct 2016 01:04:27 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0A27AC05AA43; Sat, 8 Oct 2016 05:04:26 +0000 (UTC) Received: from javelin.localdomain (vpn-236-50.phx2.redhat.com [10.3.236.50]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u9854KOo021351 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Sat, 8 Oct 2016 01:04:22 -0400 From: P J P To: Qemu Developers Date: Sat, 8 Oct 2016 10:34:18 +0530 Message-Id: <1475903058-729-1-git-send-email-ppandit@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Sat, 08 Oct 2016 05:04:26 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v4] timer: a9gtimer: remove loop to auto-increment comparator X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , qemu-arm@nongnu.org, Li Qiang , Prasad J Pandit Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP 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;