From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jacob Pan Subject: Re: [PATCH] powercap/rapl: prevent overridding bits outside of the mask Date: Tue, 27 Jun 2017 09:25:56 -0700 Message-ID: <20170627092556.082a58c7@jacob-builder> References: <20170601092150.4474-1-adam.lessnau@intel.com> <30611930.SfmUctH6tv@aspire.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mga05.intel.com ([192.55.52.43]:39868 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752530AbdF0QYS (ORCPT ); Tue, 27 Jun 2017 12:24:18 -0400 In-Reply-To: <30611930.SfmUctH6tv@aspire.rjw.lan> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Rafael J. Wysocki" Cc: Adam Lessnau , linux-pm@vger.kernel.org, jacob.jun.pan@linux.intel.com On Tue, 27 Jun 2017 02:17:32 +0200 "Rafael J. Wysocki" wrote: > On Thursday, June 01, 2017 11:21:50 AM Adam Lessnau wrote: > > Fixes wrong bits shift operation in the rapl_write_data_raw > > function, which might cause overridding bits outside of the mask. > > > > For example, writing new TIME_WINDOW1 value can override > > POWER_LIMIT1. > > > > Signed-off-by: Adam Lessnau > > Jacob, any comments? > Looks like a good fix. Thanks. > > --- > > drivers/powercap/intel_rapl.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/powercap/intel_rapl.c > > b/drivers/powercap/intel_rapl.c index 3c71f608b444..6dc27afb8527 > > 100644 --- a/drivers/powercap/intel_rapl.c > > +++ b/drivers/powercap/intel_rapl.c > > @@ -887,7 +887,9 @@ static int rapl_write_data_raw(struct > > rapl_domain *rd, > > cpu = rd->rp->lead_cpu; > > bits = rapl_unit_xlate(rd, rp->unit, value, 1); > > - bits |= bits << rp->shift; > > + bits <<= rp->shift; > > + bits &= rp->mask; > > + > > memset(&ma, 0, sizeof(ma)); > > > > ma.msr_no = rd->msrs[rp->id]; > > > [Jacob Pan]