From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752135AbdEPIul (ORCPT ); Tue, 16 May 2017 04:50:41 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:42589 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751943AbdEPIuG (ORCPT ); Tue, 16 May 2017 04:50:06 -0400 From: "Gautham R. Shenoy" To: Nicholas Piggin , Michael Ellerman , Michael Neuling , Vaidyanathan Srinivasan , Shilpasri G Bhat , Akshay Adiga , Benjamin Herrenschmidt Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, "Gautham R. Shenoy" Subject: [PATCH 2/6] powernv:idle: Decouple Timebase restore & Per-core SPRs restore Date: Tue, 16 May 2017 14:19:44 +0530 X-Mailer: git-send-email 1.8.3.1 In-Reply-To: References: In-Reply-To: References: X-TM-AS-GCONF: 00 x-cbid: 17051608-8235-0000-0000-00000B810B3F X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007070; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000212; SDB=6.00861181; UDB=6.00427106; IPR=6.00640844; BA=6.00005351; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00015477; XFM=3.00000015; UTC=2017-05-16 08:50:03 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17051608-8236-0000-0000-00003BD376B2 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-05-16_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1705160077 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Gautham R. Shenoy" On POWER8, in case of - nap: both timebase and hypervisor state is retained. - fast-sleep: timebase is lost. But the hypervisor state is retained. - winkle: timebase and hypervisor state is lost. Hence, the current code for handling exit from a idle state assumes that if the timebase value is retained, then so is the hypervisor state. Thus, the current code doesn't restore per-core hypervisor state in such cases. But that is no longer the case on POWER9 where we do have stop states in which timebase value is retained, but the hypervisor state is lost. So we have to ensure that the per-core hypervisor state gets restored in such cases. Fix this by ensuring that even in the case when timebase is retained, we explicitly check if we are waking up from a deep stop that loses per-core hypervisor state (indicated by cr4 being eq or gt), and if this is the case, we restore the per-core hypervisor state. Signed-off-by: Gautham R. Shenoy --- arch/powerpc/kernel/idle_book3s.S | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S index 4898d67..afd029f 100644 --- a/arch/powerpc/kernel/idle_book3s.S +++ b/arch/powerpc/kernel/idle_book3s.S @@ -731,13 +731,14 @@ timebase_resync: * Use cr3 which indicates that we are waking up with atleast partial * hypervisor state loss to determine if TIMEBASE RESYNC is needed. */ - ble cr3,clear_lock + ble cr3,.Ltb_resynced /* Time base re-sync */ bl opal_resync_timebase; /* - * If waking up from sleep, per core state is not lost, skip to - * clear_lock. + * If waking up from sleep (POWER8), per core state + * is not lost, skip to clear_lock. */ +.Ltb_resynced: blt cr4,clear_lock /* -- 1.8.3.1