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=-8.2 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 39CC3C433E0 for ; Thu, 9 Jul 2020 10:58:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1E68D2074B for ; Thu, 9 Jul 2020 10:58:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726970AbgGIK6d (ORCPT ); Thu, 9 Jul 2020 06:58:33 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:26870 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726921AbgGIK6a (ORCPT ); Thu, 9 Jul 2020 06:58:30 -0400 Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 069AYSIL095401; Thu, 9 Jul 2020 06:58:03 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 325r2cdv3u-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 09 Jul 2020 06:58:03 -0400 Received: from m0098414.ppops.net (m0098414.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 069Ai6Wj113896; Thu, 9 Jul 2020 06:58:02 -0400 Received: from ppma02dal.us.ibm.com (a.bd.3ea9.ip4.static.sl-reverse.com [169.62.189.10]) by mx0b-001b2d01.pphosted.com with ESMTP id 325r2cdv3j-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 09 Jul 2020 06:58:02 -0400 Received: from pps.filterd (ppma02dal.us.ibm.com [127.0.0.1]) by ppma02dal.us.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 069AtcGn030785; Thu, 9 Jul 2020 10:58:02 GMT Received: from b01cxnp23032.gho.pok.ibm.com (b01cxnp23032.gho.pok.ibm.com [9.57.198.27]) by ppma02dal.us.ibm.com with ESMTP id 325k1nq01m-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 09 Jul 2020 10:58:02 +0000 Received: from b01ledav002.gho.pok.ibm.com (b01ledav002.gho.pok.ibm.com [9.57.199.107]) by b01cxnp23032.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 069Aw12p53543332 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 9 Jul 2020 10:58:01 GMT Received: from b01ledav002.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4F4BE124053; Thu, 9 Jul 2020 10:58:01 +0000 (GMT) Received: from b01ledav002.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EE37C124052; Thu, 9 Jul 2020 10:58:00 +0000 (GMT) Received: from sofia.ibm.com (unknown [9.199.58.93]) by b01ledav002.gho.pok.ibm.com (Postfix) with ESMTP; Thu, 9 Jul 2020 10:58:00 +0000 (GMT) Received: by sofia.ibm.com (Postfix, from userid 1000) id C896D2E48BA; Thu, 9 Jul 2020 14:39:48 +0530 (IST) Date: Thu, 9 Jul 2020 14:39:48 +0530 From: Gautham R Shenoy To: Pratik Rajesh Sampat Cc: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, benh@kernel.crashing.org, paulus@samba.org, ego@linux.vnet.ibm.com, svaidy@linux.ibm.com, pratik.r.sampat@gmail.com, Ravi Bangoria Subject: Re: [PATCH 2/2] powerpc/powernv/idle: save-restore DAWR0,DAWRX0 for P10 Message-ID: <20200709090948.GB24354@in.ibm.com> Reply-To: ego@linux.vnet.ibm.com References: <20200703124640.42820-1-psampat@linux.ibm.com> <20200703124640.42820-2-psampat@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200703124640.42820-2-psampat@linux.ibm.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-07-09_05:2020-07-09,2020-07-09 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 bulkscore=0 priorityscore=1501 impostorscore=0 spamscore=0 phishscore=0 adultscore=0 lowpriorityscore=0 malwarescore=0 clxscore=1011 mlxlogscore=999 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007090084 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 03, 2020 at 06:16:40PM +0530, Pratik Rajesh Sampat wrote: > Additional registers DAWR0, DAWRX0 may be lost on Power 10 for > stop levels < 4. Adding Ravi Bangoria to the cc. > Therefore save the values of these SPRs before entering a "stop" > state and restore their values on wakeup. > > Signed-off-by: Pratik Rajesh Sampat The saving and restoration looks good to me. > --- > arch/powerpc/platforms/powernv/idle.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c > index 19d94d021357..471d4a65b1fa 100644 > --- a/arch/powerpc/platforms/powernv/idle.c > +++ b/arch/powerpc/platforms/powernv/idle.c > @@ -600,6 +600,8 @@ struct p9_sprs { > u64 iamr; > u64 amor; > u64 uamor; > + u64 dawr0; > + u64 dawrx0; > }; > > static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on) > @@ -677,6 +679,10 @@ static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on) > sprs.tscr = mfspr(SPRN_TSCR); > if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR)) > sprs.ldbar = mfspr(SPRN_LDBAR); > + if (cpu_has_feature(CPU_FTR_ARCH_31)) { > + sprs.dawr0 = mfspr(SPRN_DAWR0); > + sprs.dawrx0 = mfspr(SPRN_DAWRX0); > + } > But this is within the if condition which says if ((psscr & PSSCR_RL_MASK) >= pnv_first_spr_loss_level) This if condition is meant for stop4 and stop5 since these are stop levels that have OPAL_PM_LOSE_HYP_CONTEXT set. Since we can lose DAWR*, on states that lose limited hypervisor context, such as stop0-2, we need to unconditionally save them like AMR, IAMR etc. > sprs_saved = true; > > @@ -792,6 +798,10 @@ static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on) > mtspr(SPRN_MMCR2, sprs.mmcr2); > if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR)) > mtspr(SPRN_LDBAR, sprs.ldbar); > + if (cpu_has_feature(CPU_FTR_ARCH_31)) { > + mtspr(SPRN_DAWR0, sprs.dawr0); > + mtspr(SPRN_DAWRX0, sprs.dawrx0); > + } Likewise, we need to unconditionally restore these SPRs. > > mtspr(SPRN_SPRG3, local_paca->sprg_vdso); > > -- > 2.25.4 >