From patchwork Mon Jan 6 05:23:31 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dongsheng Wang X-Patchwork-Id: 307108 X-Patchwork-Delegate: scottwood@freescale.com Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id ABDED2C0170 for ; Mon, 6 Jan 2014 16:28:16 +1100 (EST) Received: from va3outboundpool.messaging.microsoft.com (va3ehsobe002.messaging.microsoft.com [216.32.180.12]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 456DF2C0135 for ; Mon, 6 Jan 2014 16:27:27 +1100 (EST) Received: from mail128-va3-R.bigfish.com (10.7.14.250) by VA3EHSOBE011.bigfish.com (10.7.40.61) with Microsoft SMTP Server id 14.1.225.22; Mon, 6 Jan 2014 05:27:22 +0000 Received: from mail128-va3 (localhost [127.0.0.1]) by mail128-va3-R.bigfish.com (Postfix) with ESMTP id 203AB4C00A7 for ; Mon, 6 Jan 2014 05:27:22 +0000 (UTC) X-Forefront-Antispam-Report: CIP:70.37.183.190; KIP:(null); UIP:(null); IPV:NLI; H:mail.freescale.net; RD:none; EFVD:NLI X-SpamScore: 0 X-BigFish: VS0(zzzz1f42h2148h208ch1ee6h1de0h1fdah2073h2146h1202h1e76h2189h1d1ah1d2ah1fc6hzz1de098h8275bh1de097hz2dh2a8h839hd24he5bhf0ah1288h12a5h12a9h12bdh12e5h137ah139eh13b6h1441h1504h1537h162dh1631h1758h1898h18e1h1946h19b5h1ad9h1b0ah1b2fh2222h224fh1fb3h1d0ch1d2eh1d3fh1dfeh1dffh1e23h1fe8h1ff5h2218h2216h226dh22d0h2327h2336h1155h) Received: from mail128-va3 (localhost.localdomain [127.0.0.1]) by mail128-va3 (MessageSwitch) id 1388986039818220_19538; Mon, 6 Jan 2014 05:27:19 +0000 (UTC) Received: from VA3EHSMHS001.bigfish.com (unknown [10.7.14.227]) by mail128-va3.bigfish.com (Postfix) with ESMTP id C1B101E0047; Mon, 6 Jan 2014 05:27:19 +0000 (UTC) Received: from mail.freescale.net (70.37.183.190) by VA3EHSMHS001.bigfish.com (10.7.99.11) with Microsoft SMTP Server (TLS) id 14.16.227.3; Mon, 6 Jan 2014 05:27:19 +0000 Received: from tx30smr01.am.freescale.net (10.81.153.31) by 039-SN1MMR1-003.039d.mgd.msft.net (10.84.1.16) with Microsoft SMTP Server (TLS) id 14.3.158.2; Mon, 6 Jan 2014 05:27:18 +0000 Received: from titan.ap.freescale.net (titan.ap.freescale.net [10.192.208.233]) by tx30smr01.am.freescale.net (8.14.3/8.14.0) with ESMTP id s065QWSX009418; Sun, 5 Jan 2014 22:27:17 -0700 From: Dongsheng Wang To: Subject: [PATCH v2 2/2] powerpc/mpic_timer: fix convert ticks to time subtraction overflow Date: Mon, 6 Jan 2014 13:23:31 +0800 Message-ID: <1388985811-32495-2-git-send-email-dongsheng.wang@freescale.com> X-Mailer: git-send-email 1.8.5 In-Reply-To: <1388985811-32495-1-git-send-email-dongsheng.wang@freescale.com> References: <1388985811-32495-1-git-send-email-dongsheng.wang@freescale.com> MIME-Version: 1.0 X-OriginatorOrg: freescale.com X-FOPE-CONNECTOR: Id%0$Dn%*$RO%0$TLS%0$FQDN%$TlsDn% X-FOPE-CONNECTOR: Id%0$Dn%FREESCALE.MAIL.ONMICROSOFT.COM$RO%1$TLS%0$FQDN%$TlsDn% Cc: linuxppc-dev@lists.ozlabs.org, Wang Dongsheng X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.16 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Wang Dongsheng In some cases tmp_sec may be greater than ticks, because in the process of calculation ticks and tmp_sec will be rounded. Signed-off-by: Wang Dongsheng --- v2: Add the new patch in v2. diff --git a/arch/powerpc/sysdev/mpic_timer.c b/arch/powerpc/sysdev/mpic_timer.c index 70dcf9c..9d9b062 100644 --- a/arch/powerpc/sysdev/mpic_timer.c +++ b/arch/powerpc/sysdev/mpic_timer.c @@ -97,8 +97,11 @@ static void convert_ticks_to_time(struct timer_group_priv *priv, time->tv_sec = (__kernel_time_t)div_u64(ticks, priv->timerfreq); tmp_sec = (u64)time->tv_sec * (u64)priv->timerfreq; - time->tv_usec = (__kernel_suseconds_t) - div_u64((ticks - tmp_sec) * 1000000, priv->timerfreq); + time->tv_usec = 0; + + if (tmp_sec <= ticks) + time->tv_usec = (__kernel_suseconds_t) + div_u64((ticks - tmp_sec) * 1000000, priv->timerfreq); return; }