linux-kernel - [PATCH v4 10/12] thermal: qoriq: Do not report invalid temperature reading

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190413082748.29990-11-andrew.smirnov@gmail.com>
Date:   Sat, 13 Apr 2019 01:27:46 -0700
From:   Andrey Smirnov <andrew.smirnov@...il.com>
To:     linux-pm@...r.kernel.org
Cc:     Andrey Smirnov <andrew.smirnov@...il.com>,
        Chris Healy <cphealy@...il.com>,
        Lucas Stach <l.stach@...gutronix.de>,
        Eduardo Valentin <edubezval@...il.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Angus Ainslie <angus@...ea.ca>, linux-imx@....com,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4 10/12] thermal: qoriq: Do not report invalid temperature reading

Before returning measured temperature data to upper layer we need to
make sure that the reading was marked as "valid" to avoid reporting
bogus data.

Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
Cc: Chris Healy <cphealy@...il.com>
Cc: Lucas Stach <l.stach@...gutronix.de>
Cc: Eduardo Valentin <edubezval@...il.com>
Cc: Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: Angus Ainslie (Purism) <angus@...ea.ca>
Cc: linux-imx@....com
Cc: linux-pm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
---
 drivers/thermal/qoriq_thermal.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/qoriq_thermal.c b/drivers/thermal/qoriq_thermal.c
index abbbfe88422e..5c459a9d0db3 100644
--- a/drivers/thermal/qoriq_thermal.c
+++ b/drivers/thermal/qoriq_thermal.c
@@ -37,6 +37,7 @@
 #define REGS_TRITSR(n)	(0x100 + 16 * (n)) /* Immediate Temperature
 					    * Site Register
 					    */
+#define TRITSR_V	BIT(31)
 #define REGS_TTRnCR(n)	(0xf10 + 4 * (n)) /* Temperature Range n
 					   * Control Register
 					   */
@@ -48,10 +49,25 @@ static int tmu_get_temp(int id, void *p, int *temp)
 {
 	struct qoriq_tmu_data *qdata = p;
 	u32 val;
+	/*
+	 * REGS_TRITSR(id) has the following layout:
+	 *
+	 * 31  ... 7 6 5 4 3 2 1 0
+	 *  V          TEMP
+	 *
+	 * Where V bit signifies if the measurement is ready and is
+	 * within sensor range. TEMP is an 8 bit value representing
+	 * temperature in C.
+	 */
+	if (regmap_read_poll_timeout(qdata->regmap,
+				     REGS_TRITSR(id),
+				     val,
+				     val & TRITSR_V,
+				     USEC_PER_MSEC,
+				     10 * USEC_PER_MSEC))
+		return -ENODATA;
 
-	regmap_read(qdata->regmap, REGS_TRITSR(id), &val);
 	*temp = (val & 0xff) * 1000;
-
 	return 0;
 }
 
-- 
2.20.1