From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751692AbdF1MdA (ORCPT ); Wed, 28 Jun 2017 08:33:00 -0400 Received: from ozlabs.org ([103.22.144.67]:60157 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751557AbdF1Mc4 (ORCPT ); Wed, 28 Jun 2017 08:32:56 -0400 From: Michael Ellerman To: Nicholas Piggin , Akshay Adiga Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, ego@linux.vnet.ibm.com Subject: Re: [PATCH] powernv:idle: Clear r12 on wakeup from stop lite In-Reply-To: <20170628143646.5e92bcb5@roar.ozlabs.ibm.com> References: <1498612609-13677-1-git-send-email-akshay.adiga@linux.vnet.ibm.com> <20170628143646.5e92bcb5@roar.ozlabs.ibm.com> User-Agent: Notmuch/0.21 (https://notmuchmail.org) Date: Wed, 28 Jun 2017 22:32:53 +1000 Message-ID: <87vangb8cq.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Nicholas Piggin writes: > On Wed, 28 Jun 2017 06:46:49 +0530 > Akshay Adiga wrote: > >> pnv_wakeup_noloss expects R12 to contain SRR1 value to determine if >> the wakeup reason is an HMI in CHECK_HMI_INTERRUPT. >> >> When we wakeup with ESL=0, SRR1 will not contain the wakeup reason, so >> there is no point setting R12 to SRR1. >> >> However, we don't set R12 at all and R12 contains garbage, and still >> being used to check HMI assuming that it had SRR1. causing the >> OPAL msglog to be filled with the following print: >> HMI: Received HMI interrupt: HMER = 0x0040000000000000 >> >> This patch clears R12 after waking up from stop with ESL=EC=0, so that >> we don't accidentally enter the HMI handler in pnv_wakeup_noloss if >> the R12[42:45] corresponds to HMI as wakeup reason. >> >> Bug existed prior to "commit 9d29250136f6 ("powerpc/64s/idle: Avoid SRR >> usage in idle sleep/wake paths") but was never hit in practice >> >> Signed-off-by: Akshay Adiga >> Fixes: 9d29250136f6 ("powerpc/64s/idle: Avoid SRR usage in idle >> sleep/wake paths") > > Thanks guys, appreciate you finding and fixing my bug :) > > I think this looks like the best fix. Really minor nitpick but you > could adjust the line widths on the comment slightly (mpe might do > that when merging). You know me too well :} cheers