From: Adam Lessnau <adam.lessnau@intel.com>
Date: Thu, 1 Jun 2017 09:21:50 +0000 (+0200)
Subject: powercap/RAPL: prevent overridding bits outside of the mask
X-Git-Tag: v4.13-rc1~174^2~1^4
X-Git-Url: https://git.kernelconcepts.de/?a=commitdiff_plain;h=edbdabc62328ec0ac98d83ca384bf9fd5251ade6;p=karo-tx-linux.git

powercap/RAPL: prevent overridding bits outside of the mask

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 <adam.lessnau@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

diff --git a/drivers/powercap/intel_rapl.c b/drivers/powercap/intel_rapl.c
index 9ddad0815ba9..d1694f1def72 100644
--- a/drivers/powercap/intel_rapl.c
+++ b/drivers/powercap/intel_rapl.c
@@ -874,7 +874,9 @@ 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];