All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ryo Takakura <ryotkkr98@gmail.com>
To: alex@ghiti.fr, aou@eecs.berkeley.edu, gregkh@linuxfoundation.org,
	jirislaby@kernel.org, john.ogness@linutronix.de,
	palmer@dabbelt.com, paul.walmsley@sifive.com, pmladek@suse.com,
	samuel.holland@sifive.com, bigeasy@linutronix.de,
	conor.dooley@microchip.com, u.kleine-koenig@baylibre.com,
	lkp@intel.com
Cc: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-serial@vger.kernel.org, stable@vger.kernel.org,
	oe-kbuild-all@lists.linux.dev, Ryo Takakura <ryotkkr98@gmail.com>
Subject: Re: [PATCH v2 1/2] serial: sifive: lock port in startup()/shutdown() callbacks
Date: Sun, 30 Mar 2025 10:16:10 +0900	[thread overview]
Message-ID: <20250330011610.388077-1-ryotkkr98@gmail.com> (raw)
In-Reply-To: <Z-iSb0ryR-tiUCj0@42be267012b8>

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
---

Hi,

I'm sorry that I wasn't aware of how Cc stable should be done. 

I added Cc for stable but please tell me if this patch should be
resent or if there is any that is missing.

Sincerely,
Ryo Takakura

---
 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


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

WARNING: multiple messages have this Message-ID (diff)
From: Ryo Takakura <ryotkkr98@gmail.com>
To: alex@ghiti.fr, aou@eecs.berkeley.edu, gregkh@linuxfoundation.org,
	jirislaby@kernel.org, john.ogness@linutronix.de,
	palmer@dabbelt.com, paul.walmsley@sifive.com, pmladek@suse.com,
	samuel.holland@sifive.com, bigeasy@linutronix.de,
	conor.dooley@microchip.com, u.kleine-koenig@baylibre.com,
	lkp@intel.com
Cc: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-serial@vger.kernel.org, stable@vger.kernel.org,
	oe-kbuild-all@lists.linux.dev, Ryo Takakura <ryotkkr98@gmail.com>
Subject: Re: [PATCH v2 1/2] serial: sifive: lock port in startup()/shutdown() callbacks
Date: Sun, 30 Mar 2025 10:16:10 +0900	[thread overview]
Message-ID: <20250330011610.388077-1-ryotkkr98@gmail.com> (raw)
In-Reply-To: <Z-iSb0ryR-tiUCj0@42be267012b8>

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
---

Hi,

I'm sorry that I wasn't aware of how Cc stable should be done. 

I added Cc for stable but please tell me if this patch should be
resent or if there is any that is missing.

Sincerely,
Ryo Takakura

---
 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:[~2025-03-30  1:17 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-30  0:30 [PATCH v2 0/2] serial: sifive: Convert sifive console to nbcon Ryo Takakura
2025-03-30  0:30 ` Ryo Takakura
2025-03-30  0:35 ` [PATCH v2 1/2] serial: sifive: lock port in startup()/shutdown() callbacks Ryo Takakura
2025-03-30  0:35   ` Ryo Takakura
2025-03-30  0:38   ` kernel test robot
2025-03-30  1:16     ` Ryo Takakura [this message]
2025-03-30  1:16       ` Ryo Takakura
2025-03-30  7:30       ` Greg KH
2025-03-30  7:30         ` Greg KH
2025-03-30 10:51         ` Ryo Takakura
2025-03-30 10:51           ` Ryo Takakura
2025-03-30  0:40 ` [PATCH v2 2/2] serial: sifive: Switch to nbcon console Ryo Takakura
2025-03-30  0:40   ` Ryo Takakura

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20250330011610.388077-1-ryotkkr98@gmail.com \
    --to=ryotkkr98@gmail.com \
    --cc=alex@ghiti.fr \
    --cc=aou@eecs.berkeley.edu \
    --cc=bigeasy@linutronix.de \
    --cc=conor.dooley@microchip.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=jirislaby@kernel.org \
    --cc=john.ogness@linutronix.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=linux-serial@vger.kernel.org \
    --cc=lkp@intel.com \
    --cc=oe-kbuild-all@lists.linux.dev \
    --cc=palmer@dabbelt.com \
    --cc=paul.walmsley@sifive.com \
    --cc=pmladek@suse.com \
    --cc=samuel.holland@sifive.com \
    --cc=stable@vger.kernel.org \
    --cc=u.kleine-koenig@baylibre.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.