Received-SPF: softfail (google.com: domain of transitioning linux-kernel-owner@vger.kernel.org does not designate 23.128.96.19 as permitted sender) client-ip=23.128.96.19;
From:   Qing Wang <wangqing@vivo.com>
To:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        linux-kernel@vger.kernel.org
Cc:     Wang Qing <wangqing@vivo.com>
Subject: [PATCH] x86: tsc: use div64_u64() instead of do_div()
Date:   Wed,  9 Feb 2022 00:35:13 -0800
Message-Id: <1644395713-3593-1-git-send-email-wangqing@vivo.com>
Content-Type: text/plain
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?MD5b1pfLtbxc6zx8vMjOIqW6AhbZ3B8HvjpJuAmtEx4dRhWOQhYiQSp2jiZo?=
 =?us-ascii?Q?+gQK6Cr4blg7Mlu3hFcffRIZk3n4RkVpBVsw1o1WWGynP+MzASj0utJbJmr8?=
 =?us-ascii?Q?duN+E1ua4fWtEV0NpbsWupL3pc04ygIYInVpm8KoAhWbD+lD6ebMPG9SXzyw?=
 =?us-ascii?Q?hxJ7mf3Z1cS+bOEwYDZzJIOicFq8y7Ydr8emrG8uynG3iYJgbQvhBkXDIHdr?=
 =?us-ascii?Q?zDaklDx6lSluO6nXl44IgqdDacxUUI7H7bteOm9RhU5yAMzyg8nz2aKnbosR?=
 =?us-ascii?Q?dN3KyXxNDKXvAeSBIB5iSQCBNidyPOVz7ZxO36j0cuBUDd/lFNQ0/t91gEAK?=
 =?us-ascii?Q?Ng4O87nBw7Mxu5DEmNvTD/kv+SkVBaemBCAka906W7Yz1Mvr6D8WLmFErVFe?=
 =?us-ascii?Q?4WvAvFPexLBbNHAnAG8PdAyrKiwLpsZXQgVou7iBCTYrUtXRG7dK/lxzpLCI?=
 =?us-ascii?Q?NMSe4up5NJ1uspz519C4i7WxCk9Zd1RsjTgaF7qSJnszxWzg32myLIBNAFNk?=
 =?us-ascii?Q?LtJmt//hMFHYvqMKbZ+pRZzpsbqbSg21XbjKsf4utzub0pbXTeQzPra89vKQ?=
 =?us-ascii?Q?7b3FBv03f+8HgLbdJcH17BzR9DaTHdkdMaRpTcB1gpXDhRvvfTH/gyvbVN7u?=
 =?us-ascii?Q?ZH9VO50LO5uiehZBYnrh7pBV0adKy6omHyt8b8fynwnRDXRiSAo1B0FX2pFg?=
 =?us-ascii?Q?UTddNM9xG+k+Qnzdv1IrUPevgFyE5FV9jPC1SKXT5EELlcCCb1Fz+pdZlqJZ?=
 =?us-ascii?Q?NjdqfysrxNZ/hNHmIexTCIRBvK56080I3hj5cvgmHSSnOKPrgJIMVUkq7ALp?=
 =?us-ascii?Q?nuooRcssbk+ZRyr4rasvvzY50+Bh6blmOtIRDORvXyGB8PvzqYp8tVY5ABXQ?=
 =?us-ascii?Q?XQj/y+KvQmKTJeCgBS0ABm/hagMjMYMgZ9D8YttzwBQdDN4dD7tju4tTGlwt?=
 =?us-ascii?Q?krsWlEiqqACpfPV1BP6toBeh8Btii7/ZEbEfla0qiS2rTtdo+tQUK4lfYsNc?=
 =?us-ascii?Q?uO5crEViWixlODRTv9EAKceAndqbcqY1zSVHxU4kyTPrkP/WnDElHlTdbHYq?=
 =?us-ascii?Q?hP8v7ySQkTjn5yrBlYVyj2REW6+2sqXO9CZk8qZF06FAGGoITvphi2lOAhpa?=
 =?us-ascii?Q?qmGwiIUvgYHloi8ApcEhVRuE4IxApbpD/ew7ZiA2TOlZqUZVQXXQuv/GOeeE?=
 =?us-ascii?Q?dxp5j+DpcN45yJ0PbI4eRPc88xzkpw8dn18EJSjaU6sM9MiqAuhzLPiiclwx?=
 =?us-ascii?Q?7h+ou2sd1e6sY5SOGZNdd/XNIxrDzI+BlAXLAWJN9Uov9IeqjkLM6xLhMpSU?=
 =?us-ascii?Q?yfMr9m7TWPCKqBjJeY2eI9QZP/i04g/oqEjPos8J5oNsfkalMb3UKIvuZINZ?=
 =?us-ascii?Q?b73hT9r1d4M4WWFVTF/xeI7TjnF2HyNf/PZpdDPAT7Cr9Ws06o8EF/SziXO9?=
 =?us-ascii?Q?Twz3Db8ZGQhKYK8Pt+joPyYlJ/rEggZiY+bIMUH6n3eYuAGBNEXSDqesrLoy?=
 =?us-ascii?Q?GznjM/cGT82FqeAGQiHdXz4EZQR3JMNvl5WzGIK/zU8I5z+BzPC0CQOPlOPF?=
 =?us-ascii?Q?n6e6/sfNV7Ooy5lUNRMzSLMUDz+8ETWCftyhByj5t7RphpPhXNaCj1Gu9/RO?=
 =?us-ascii?Q?atb3OB67wgb8XlttgQj3FOI=3D?=
X-OriginatorOrg: vivo.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 3aee8ed5-ec92-4895-d673-08d9eba71d76
X-MS-Exchange-CrossTenant-AuthSource: SL2PR06MB3082.apcprd06.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Feb 2022 08:35:23.8685
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 923e42dc-48d5-4cbe-b582-1a797a6412ed
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: YmJ1d2UTpnNiEh4WIP2EEfq57gN1J2lo5soMpvxjEaQbZqkssVrgi8eFq2K+URPByD8WubjwGJDzz0QoXRb0nw==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PS2PR06MB3559
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED,
	DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RDNS_NONE,
	SPF_HELO_NONE,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no
	version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
	lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: Wang Qing <wangqing@vivo.com>

do_div() does a 64-by-32 division.
When the divisor is u64, do_div() truncates it to 32 bits, this means it
can test non-zero and be truncated to zero for division.

fix do_div.cocci warning:
do_div() does a 64-by-32 division, please consider using div64_u64 instead.

Signed-off-by: Wang Qing <wangqing@vivo.com>
---
 arch/x86/kernel/tsc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index a698196..e97124c
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -365,7 +365,7 @@ static unsigned long calc_pmtimer_ref(u64 deltatsc, u64 pm1, u64 pm2)
 	pm2 -= pm1;
 	tmp = pm2 * 1000000000LL;
 	do_div(tmp, PMTMR_TICKS_PER_SEC);
-	do_div(deltatsc, tmp);
+	div64_u64(deltatsc, tmp);
 
 	return (unsigned long) deltatsc;
 }
-- 
2.7.4