linux-kernel - [PATCH 3.16.y-ckt 061/128] powercap / RAPL: fix BIOS lock check

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Message-Id: <1453672883-2708-62-git-send-email-luis.henriques@canonical.com>
Date:	Sun, 24 Jan 2016 22:00:16 +0000
From:	Luis Henriques <luis.henriques@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Prarit Bhargava <prarit@...hat.com>,
	"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
	Luis Henriques <luis.henriques@...onical.com>
Subject: [PATCH 3.16.y-ckt 061/128] powercap / RAPL: fix BIOS lock check

3.16.7-ckt23 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Prarit Bhargava <prarit@...hat.com>

commit 79a21dbfae3cd40d5a801778071a9967b79c2c20 upstream.

Intel RAPL initialized on several systems where the BIOS lock bit (msr
0x610, bit 63) was set.  This occured because the return value of
rapl_read_data_raw() was being checked, rather than the value of the variable
passed in, locked.

This patch properly implments the rapl_read_data_raw() call to check the
variable locked, and now the Intel RAPL driver outputs the warning:

	intel_rapl: RAPL package 0 domain package locked by BIOS

and does not initialize for the package.

Signed-off-by: Prarit Bhargava <prarit@...hat.com>
Acked-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Luis Henriques <luis.henriques@...onical.com>
---
 drivers/powercap/intel_rapl.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/powercap/intel_rapl.c b/drivers/powercap/intel_rapl.c
index a362dcc20ec0..ccb6768a352b 100644
--- a/drivers/powercap/intel_rapl.c
+++ b/drivers/powercap/intel_rapl.c
@@ -1191,10 +1191,13 @@ static int rapl_detect_domains(struct rapl_package *rp, int cpu)
 
 	for (rd = rp->domains; rd < rp->domains + rp->nr_domains; rd++) {
 		/* check if the domain is locked by BIOS */
-		if (rapl_read_data_raw(rd, FW_LOCK, false, &locked)) {
+		ret = rapl_read_data_raw(rd, FW_LOCK, false, &locked);
+		if (ret)
+			return ret;
+		if (locked) {
 			pr_info("RAPL package %d domain %s locked by BIOS\n",
 				rp->id, rd->name);
-				rd->state |= DOMAIN_STATE_BIOS_LOCKED;
+			rd->state |= DOMAIN_STATE_BIOS_LOCKED;
 		}
 	}