From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH] powercap/rapl: prevent overridding bits outside of the mask Date: Tue, 27 Jun 2017 02:17:32 +0200 Message-ID: <30611930.SfmUctH6tv@aspire.rjw.lan> References: <20170601092150.4474-1-adam.lessnau@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: Received: from cloudserver094114.home.net.pl ([79.96.170.134]:45245 "EHLO cloudserver094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751461AbdF0AY4 (ORCPT ); Mon, 26 Jun 2017 20:24:56 -0400 In-Reply-To: <20170601092150.4474-1-adam.lessnau@intel.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Adam Lessnau , Jacob Pan Cc: linux-pm@vger.kernel.org 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? > --- > 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]; >