linux-kernel - [PATCH] powercap, intel_rapl.c, fix BIOS lock check

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Date:	Tue,  8 Dec 2015 13:33:22 -0500
From:	Prarit Bhargava <prarit@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	Prarit Bhargava <prarit@...hat.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Jacob Pan <jacob.jun.pan@...ux.intel.com>,
	Radivoje Jovanovic <radivoje.jovanovic@...el.com>,
	Seiichi Ikarashi <s.ikarashi@...fujitsu.com>,
	Mathias Krause <minipli@...glemail.com>,
	Ajay Thomas <ajay.thomas.david.rajamanickam@...el.com>
Subject: [PATCH] powercap, intel_rapl.c, fix BIOS lock check

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.

Cc: "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Cc: Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc: Radivoje Jovanovic <radivoje.jovanovic@...el.com>
Cc: Seiichi Ikarashi <s.ikarashi@...fujitsu.com>
Cc: Mathias Krause <minipli@...glemail.com>
Cc: Ajay Thomas <ajay.thomas.david.rajamanickam@...el.com>
Signed-off-by: Prarit Bhargava <prarit@...hat.com>
---
 drivers/powercap/intel_rapl.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/powercap/intel_rapl.c b/drivers/powercap/intel_rapl.c
index cc97f08..0b0d09d 100644
--- a/drivers/powercap/intel_rapl.c
+++ b/drivers/powercap/intel_rapl.c
@@ -1341,11 +1341,13 @@ 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;
-		}
 	}
 
 
-- 
1.7.9.3

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