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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 472A7C33CB1 for ; Wed, 15 Jan 2020 14:30:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 230CC2073A for ; Wed, 15 Jan 2020 14:30:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729015AbgAOOal (ORCPT ); Wed, 15 Jan 2020 09:30:41 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:65264 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726472AbgAOOal (ORCPT ); Wed, 15 Jan 2020 09:30:41 -0500 Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 00FER4Sx110917; Wed, 15 Jan 2020 09:30:05 -0500 Received: from ppma04wdc.us.ibm.com (1a.90.2fa9.ip4.static.sl-reverse.com [169.47.144.26]) by mx0b-001b2d01.pphosted.com with ESMTP id 2xhgs6npvt-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 15 Jan 2020 09:30:05 -0500 Received: from pps.filterd (ppma04wdc.us.ibm.com [127.0.0.1]) by ppma04wdc.us.ibm.com (8.16.0.27/8.16.0.27) with SMTP id 00FESoBW014686; Wed, 15 Jan 2020 14:30:05 GMT Received: from b03cxnp08027.gho.boulder.ibm.com (b03cxnp08027.gho.boulder.ibm.com [9.17.130.19]) by ppma04wdc.us.ibm.com with ESMTP id 2xf751x35c-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 15 Jan 2020 14:30:05 +0000 Received: from b03ledav004.gho.boulder.ibm.com (b03ledav004.gho.boulder.ibm.com [9.17.130.235]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 00FEU4uB43647418 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 15 Jan 2020 14:30:04 GMT Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id ECC0B7805F; Wed, 15 Jan 2020 14:30:03 +0000 (GMT) Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3620378060; Wed, 15 Jan 2020 14:30:03 +0000 (GMT) Received: from oc8380061452.ibm.com (unknown [9.80.230.130]) by b03ledav004.gho.boulder.ibm.com (Postfix) with ESMTP; Wed, 15 Jan 2020 14:30:02 +0000 (GMT) Subject: Re: [PATCH] Fix display of Maximum Memory To: Christophe Leroy , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Cc: Gustavo Walbon , Paul Mackerras References: <55f25626-20ca-0acb-3571-ff636ca4632c@linux.ibm.com> <41380afd-05f5-f36f-c857-041243c73ee3@c-s.fr> From: Michael Bringmann Openpgp: preference=signencrypt Organization: IBM Linux Technology Center Message-ID: Date: Wed, 15 Jan 2020 08:30:02 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 MIME-Version: 1.0 In-Reply-To: <41380afd-05f5-f36f-c857-041243c73ee3@c-s.fr> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-01-15_02:2020-01-15,2020-01-15 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 mlxscore=0 malwarescore=0 suspectscore=0 mlxlogscore=999 impostorscore=0 spamscore=0 bulkscore=0 lowpriorityscore=0 clxscore=1011 priorityscore=1501 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-2001150117 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/14/20 11:41 PM, Christophe Leroy wrote: > > > Le 14/01/2020 à 22:07, Michael Bringmann a écrit : >> Correct overflow problem in calculation+display of Maximum Memory >> value to syscfg where 32bits is insufficient. >> >> Signed-off-by: Michael Bringmann >> --- >>   arch/powerpc/platforms/pseries/lparcfg.c | 8 ++++---- >>   1 file changed, 4 insertions(+), 4 deletions(-) >> >> diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c >> index 4ee2594..183aeb7 100644 >> --- a/arch/powerpc/platforms/pseries/lparcfg.c >> +++ b/arch/powerpc/platforms/pseries/lparcfg.c >> @@ -435,12 +435,12 @@ static void parse_em_data(struct seq_file *m) >> >>   static void maxmem_data(struct seq_file *m) >>   { >> -       unsigned long maxmem = 0; >> +       unsigned long long maxmem = 0; > > What about using u64 instead, for readability ? Okay. > >> >> -       maxmem += drmem_info->n_lmbs * drmem_info->lmb_size; >> -       maxmem += hugetlb_total_pages() * PAGE_SIZE; >> +       maxmem += (unsigned long long)drmem_info->n_lmbs * (unsigned long long)drmem_info->lmb_size; > > This line is likely too long. You only need to cast one of the two operants to force a 64 bits multiply. And using u64 would shorten the line. > > Can both multiplications overflow ? Yes. > > Christophe > >> +       maxmem += (unsigned long long)hugetlb_total_pages() * (unsigned long long)PAGE_SIZE; >> >> -       seq_printf(m, "MaxMem=%ld\n", maxmem); >> +       seq_printf(m, "MaxMem=%llu\n", maxmem); >>   } >> >>   static int pseries_lparcfg_data(struct seq_file *m, void *v) >> > Thanks. -- Michael W. Bringmann Linux Technology Center IBM Corporation Tie-Line 363-5196 External: (512) 286-5196 Cell: (512) 466-0650 mwb@linux.ibm.com