linux-kernel - [PATCH AUTOSEL 4.19 426/671] rtc: pcf8563: Clear event flags and disable interrupts before requesting irq

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: <20200116170509.12787-163-sashal@kernel.org>
Date:   Thu, 16 Jan 2020 12:01:04 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Chen-Yu Tsai <wens@...e.org>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Sasha Levin <sashal@...nel.org>, linux-rtc@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 426/671] rtc: pcf8563: Clear event flags and disable interrupts before requesting irq

From: Chen-Yu Tsai <wens@...e.org>

[ Upstream commit 3572e8aea3bf925dac1dbf86127657c39fe5c254 ]

Besides the alarm, the PCF8563 also has a timer triggered interrupt.
In cases where the previous system left the timer and interrupts on,
or somehow the bits got enabled, the interrupt would keep triggering
as the kernel doesn't know about it.

Clear both the alarm and timer event flags, and disable the interrupts,
before requesting the interrupt line.

Fixes: ede3e9d47cca ("drivers/rtc/rtc-pcf8563.c: add alarm support")
Fixes: a45d528aab8b ("rtc: pcf8563: clear expired alarm at boot time")
Signed-off-by: Chen-Yu Tsai <wens@...e.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/rtc/rtc-pcf8563.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-pcf8563.c b/drivers/rtc/rtc-pcf8563.c
index e358313466f1..d8adf69b6697 100644
--- a/drivers/rtc/rtc-pcf8563.c
+++ b/drivers/rtc/rtc-pcf8563.c
@@ -563,7 +563,6 @@ static int pcf8563_probe(struct i2c_client *client,
 	struct pcf8563 *pcf8563;
 	int err;
 	unsigned char buf;
-	unsigned char alm_pending;
 
 	dev_dbg(&client->dev, "%s\n", __func__);
 
@@ -587,13 +586,13 @@ static int pcf8563_probe(struct i2c_client *client,
 		return err;
 	}
 
-	err = pcf8563_get_alarm_mode(client, NULL, &alm_pending);
-	if (err) {
-		dev_err(&client->dev, "%s: read error\n", __func__);
+	/* Clear flags and disable interrupts */
+	buf = 0;
+	err = pcf8563_write_block_data(client, PCF8563_REG_ST2, 1, &buf);
+	if (err < 0) {
+		dev_err(&client->dev, "%s: write error\n", __func__);
 		return err;
 	}
-	if (alm_pending)
-		pcf8563_set_alarm_mode(client, 0);
 
 	pcf8563->rtc = devm_rtc_device_register(&client->dev,
 				pcf8563_driver.driver.name,
-- 
2.20.1