From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90828C31E5B for ; Tue, 18 Jun 2019 17:21:50 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 68BC321479 for ; Tue, 18 Jun 2019 17:21:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 68BC321479 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kaod.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:60434 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hdHnp-0003MJ-MZ for qemu-devel@archiver.kernel.org; Tue, 18 Jun 2019 13:21:49 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60781) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hdHNb-0000hj-Uv for qemu-devel@nongnu.org; Tue, 18 Jun 2019 12:54:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hdHNa-0004sS-Uv for qemu-devel@nongnu.org; Tue, 18 Jun 2019 12:54:43 -0400 Received: from 8.mo68.mail-out.ovh.net ([46.105.74.219]:56096) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hdHNa-0004qU-NK for qemu-devel@nongnu.org; Tue, 18 Jun 2019 12:54:42 -0400 Received: from player157.ha.ovh.net (unknown [10.108.35.210]) by mo68.mail-out.ovh.net (Postfix) with ESMTP id DF6F313288E for ; Tue, 18 Jun 2019 18:54:40 +0200 (CEST) Received: from kaod.org (lfbn-1-10649-41.w90-89.abo.wanadoo.fr [90.89.235.41]) (Authenticated sender: clg@kaod.org) by player157.ha.ovh.net (Postfix) with ESMTPSA id 543166EB538B; Tue, 18 Jun 2019 16:54:33 +0000 (UTC) From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= To: Peter Maydell Date: Tue, 18 Jun 2019 18:53:01 +0200 Message-Id: <20190618165311.27066-12-clg@kaod.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190618165311.27066-1-clg@kaod.org> References: <20190618165311.27066-1-clg@kaod.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Ovh-Tracer-Id: 1679842663082658577 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgeduvddrtddtgdejjecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfqggfjpdevjffgvefmvefgnecuuegrihhlohhuthemucehtddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 46.105.74.219 Subject: [Qemu-devel] [PATCH v2 11/21] aspeed/timer: Ensure positive muldiv delta X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Christian Svensson , Andrew Jeffery , qemu-devel@nongnu.org, qemu-arm@nongnu.org, =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , Joel Stanley Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Christian Svensson If the host decrements the counter register that results in a negative delta. This is then passed to muldiv64 which only handles unsigned numbers resulting in bogus results. This fix ensures the delta being operated on is positive. Test case: kexec a kernel using aspeed_timer and it will freeze on the second bootup when the kernel initializes the timer. With this patch that no longer happens and the timer appears to run OK. Signed-off-by: Christian Svensson Signed-off-by: C=C3=A9dric Le Goater --- hw/timer/aspeed_timer.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/hw/timer/aspeed_timer.c b/hw/timer/aspeed_timer.c index 6501fa0768e7..1f0f1886fb2a 100644 --- a/hw/timer/aspeed_timer.c +++ b/hw/timer/aspeed_timer.c @@ -275,7 +275,11 @@ static void aspeed_timer_set_value(AspeedTimerCtrlSt= ate *s, int timer, int reg, int64_t delta =3D (int64_t) value - (int64_t) calculate_tick= s(t, now); uint32_t rate =3D calculate_rate(t); =20 - t->start +=3D muldiv64(delta, NANOSECONDS_PER_SECOND, rate); + if (delta >=3D 0) { + t->start +=3D muldiv64(delta, NANOSECONDS_PER_SECOND, ra= te); + } else { + t->start -=3D muldiv64(-delta, NANOSECONDS_PER_SECOND, r= ate); + } aspeed_timer_mod(t); } break; --=20 2.21.0