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From: Ryo Takakura <ryotkkr98@gmail.com>
To: alex@ghiti.fr, aou@eecs.berkeley.edu, bigeasy@linutronix.de,
	conor.dooley@microchip.com, gregkh@linuxfoundation.org,
	jirislaby@kernel.org, john.ogness@linutronix.de,
	palmer@dabbelt.com, paul.walmsley@sifive.com, pmladek@suse.com,
	samuel.holland@sifive.com, u.kleine-koenig@baylibre.com
Cc: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-serial@vger.kernel.org, stable@vger.kernel.org,
	Ryo Takakura <ryotkkr98@gmail.com>
Subject: [PATCH v4 1/2] serial: sifive: lock port in startup()/shutdown() callbacks
Date: Sat,  5 Apr 2025 13:43:38 +0900	[thread overview]
Message-ID: <20250405044338.397237-1-ryotkkr98@gmail.com> (raw)
In-Reply-To: <20250405043833.397020-1-ryotkkr98@gmail.com>

startup()/shutdown() callbacks access SIFIVE_SERIAL_IE_OFFS.
The register is also accessed from write() callback.

If console were printing and startup()/shutdown() callback
gets called, its access to the register could be overwritten.

Add port->lock to startup()/shutdown() callbacks to make sure
their access to SIFIVE_SERIAL_IE_OFFS is synchronized against
write() callback.

Signed-off-by: Ryo Takakura <ryotkkr98@gmail.com>
Cc: stable@vger.kernel.org
---
 drivers/tty/serial/sifive.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c
index 5904a2d4c..054a8e630 100644
--- a/drivers/tty/serial/sifive.c
+++ b/drivers/tty/serial/sifive.c
@@ -563,8 +563,11 @@ static void sifive_serial_break_ctl(struct uart_port *port, int break_state)
 static int sifive_serial_startup(struct uart_port *port)
 {
 	struct sifive_serial_port *ssp = port_to_sifive_serial_port(port);
+	unsigned long flags;
 
+	uart_port_lock_irqsave(&ssp->port, &flags);
 	__ssp_enable_rxwm(ssp);
+	uart_port_unlock_irqrestore(&ssp->port, flags);
 
 	return 0;
 }
@@ -572,9 +575,12 @@ static int sifive_serial_startup(struct uart_port *port)
 static void sifive_serial_shutdown(struct uart_port *port)
 {
 	struct sifive_serial_port *ssp = port_to_sifive_serial_port(port);
+	unsigned long flags;
 
+	uart_port_lock_irqsave(&ssp->port, &flags);
 	__ssp_disable_rxwm(ssp);
 	__ssp_disable_txwm(ssp);
+	uart_port_unlock_irqrestore(&ssp->port, flags);
 }
 
 /**
-- 
2.34.1


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WARNING: multiple messages have this Message-ID (diff)
From: Ryo Takakura <ryotkkr98@gmail.com>
To: alex@ghiti.fr, aou@eecs.berkeley.edu, bigeasy@linutronix.de,
	conor.dooley@microchip.com, gregkh@linuxfoundation.org,
	jirislaby@kernel.org, john.ogness@linutronix.de,
	palmer@dabbelt.com, paul.walmsley@sifive.com, pmladek@suse.com,
	samuel.holland@sifive.com, u.kleine-koenig@baylibre.com
Cc: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-serial@vger.kernel.org, stable@vger.kernel.org,
	Ryo Takakura <ryotkkr98@gmail.com>
Subject: [PATCH v4 1/2] serial: sifive: lock port in startup()/shutdown() callbacks
Date: Sat,  5 Apr 2025 13:43:38 +0900	[thread overview]
Message-ID: <20250405044338.397237-1-ryotkkr98@gmail.com> (raw)
In-Reply-To: <20250405043833.397020-1-ryotkkr98@gmail.com>

startup()/shutdown() callbacks access SIFIVE_SERIAL_IE_OFFS.
The register is also accessed from write() callback.

If console were printing and startup()/shutdown() callback
gets called, its access to the register could be overwritten.

Add port->lock to startup()/shutdown() callbacks to make sure
their access to SIFIVE_SERIAL_IE_OFFS is synchronized against
write() callback.

Signed-off-by: Ryo Takakura <ryotkkr98@gmail.com>
Cc: stable@vger.kernel.org
---
 drivers/tty/serial/sifive.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c
index 5904a2d4c..054a8e630 100644
--- a/drivers/tty/serial/sifive.c
+++ b/drivers/tty/serial/sifive.c
@@ -563,8 +563,11 @@ static void sifive_serial_break_ctl(struct uart_port *port, int break_state)
 static int sifive_serial_startup(struct uart_port *port)
 {
 	struct sifive_serial_port *ssp = port_to_sifive_serial_port(port);
+	unsigned long flags;
 
+	uart_port_lock_irqsave(&ssp->port, &flags);
 	__ssp_enable_rxwm(ssp);
+	uart_port_unlock_irqrestore(&ssp->port, flags);
 
 	return 0;
 }
@@ -572,9 +575,12 @@ static int sifive_serial_startup(struct uart_port *port)
 static void sifive_serial_shutdown(struct uart_port *port)
 {
 	struct sifive_serial_port *ssp = port_to_sifive_serial_port(port);
+	unsigned long flags;
 
+	uart_port_lock_irqsave(&ssp->port, &flags);
 	__ssp_disable_rxwm(ssp);
 	__ssp_disable_txwm(ssp);
+	uart_port_unlock_irqrestore(&ssp->port, flags);
 }
 
 /**
-- 
2.34.1


  reply	other threads:[~2025-04-05  4:44 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-05  4:38 [PATCH v4 0/2] serial: sifive: Convert sifive console to nbcon Ryo Takakura
2025-04-05  4:38 ` Ryo Takakura
2025-04-05  4:43 ` Ryo Takakura [this message]
2025-04-05  4:43   ` [PATCH v4 1/2] serial: sifive: lock port in startup()/shutdown() callbacks Ryo Takakura
2025-04-05  7:35   ` Greg KH
2025-04-05  7:35     ` Greg KH
2025-04-05 11:23     ` Ryo Takakura
2025-04-05 11:23       ` Ryo Takakura
2025-04-22 10:20     ` Vlastimil Babka
2025-04-22 10:20       ` Vlastimil Babka
2025-04-22 10:50       ` Greg KH
2025-04-22 10:50         ` Greg KH
2025-04-22 13:07         ` Vlastimil Babka
2025-04-22 13:07           ` Vlastimil Babka
2025-04-22 13:16           ` Greg KH
2025-04-22 13:16             ` Greg KH
2025-04-25  9:02             ` Petr Mladek
2025-04-25  9:02               ` Petr Mladek
2025-04-05  4:47 ` [PATCH v4 2/2] serial: sifive: Switch to nbcon console Ryo Takakura
2025-04-05  4:47   ` Ryo Takakura

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