The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 5f1017069933489add0c08659673443c9905659e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025021029-hunger-quizzical-9965@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 5f1017069933489add0c08659673443c9905659e Mon Sep 17 00:00:00 2001
From: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Date: Thu, 16 Jan 2025 20:22:48 +0200
Subject: [PATCH] serial: sh-sci: Clean sci_ports[0] after at earlycon exit
The early_console_setup() function initializes sci_ports[0].port with an
object of type struct uart_port obtained from the struct earlycon_device
passed as an argument to early_console_setup().
Later, during serial port probing, the serial port used as earlycon
(e.g., port A) might be remapped to a different position in the sci_ports[]
array, and a different serial port (e.g., port B) might be assigned to slot
0. For example:
sci_ports[0] = port B
sci_ports[X] = port A
In this scenario, the new port mapped at index zero (port B) retains the
data associated with the earlycon configuration. Consequently, after the
Linux boot process, any access to the serial port now mapped to
sci_ports[0] (port B) will block the original earlycon port (port A).
To address this, introduce an early_console_exit() function to clean up
sci_ports[0] when earlycon is exited.
To prevent the cleanup of sci_ports[0] while the serial device is still
being used by earlycon, introduce the struct sci_port::probing flag and
account for it in early_console_exit().
Fixes: 0b0cced19ab1 ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Link: https://lore.kernel.org/r/20250116182249.3828577-5-claudiu.beznea.uj@bp.ren…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index b85a9d425f7e..e64d59888ecd 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -166,6 +166,7 @@ static struct sci_port sci_ports[SCI_NPORTS];
static unsigned long sci_ports_in_use;
static struct uart_driver sci_uart_driver;
static bool sci_uart_earlycon;
+static bool sci_uart_earlycon_dev_probing;
static inline struct sci_port *
to_sci_port(struct uart_port *uart)
@@ -3386,7 +3387,8 @@ static struct plat_sci_port *sci_parse_dt(struct platform_device *pdev,
static int sci_probe_single(struct platform_device *dev,
unsigned int index,
struct plat_sci_port *p,
- struct sci_port *sciport)
+ struct sci_port *sciport,
+ struct resource *sci_res)
{
int ret;
@@ -3433,6 +3435,14 @@ static int sci_probe_single(struct platform_device *dev,
sciport->port.flags |= UPF_HARD_FLOW;
}
+ if (sci_uart_earlycon && sci_ports[0].port.mapbase == sci_res->start) {
+ /*
+ * Skip cleanup the sci_port[0] in early_console_exit(), this
+ * port is the same as the earlycon one.
+ */
+ sci_uart_earlycon_dev_probing = true;
+ }
+
return uart_add_one_port(&sci_uart_driver, &sciport->port);
}
@@ -3491,7 +3501,7 @@ static int sci_probe(struct platform_device *dev)
platform_set_drvdata(dev, sp);
- ret = sci_probe_single(dev, dev_id, p, sp);
+ ret = sci_probe_single(dev, dev_id, p, sp, res);
if (ret)
return ret;
@@ -3574,6 +3584,22 @@ sh_early_platform_init_buffer("earlyprintk", &sci_driver,
#ifdef CONFIG_SERIAL_SH_SCI_EARLYCON
static struct plat_sci_port port_cfg;
+static int early_console_exit(struct console *co)
+{
+ struct sci_port *sci_port = &sci_ports[0];
+
+ /*
+ * Clean the slot used by earlycon. A new SCI device might
+ * map to this slot.
+ */
+ if (!sci_uart_earlycon_dev_probing) {
+ memset(sci_port, 0, sizeof(*sci_port));
+ sci_uart_earlycon = false;
+ }
+
+ return 0;
+}
+
static int __init early_console_setup(struct earlycon_device *device,
int type)
{
@@ -3591,6 +3617,8 @@ static int __init early_console_setup(struct earlycon_device *device,
SCSCR_RE | SCSCR_TE | port_cfg.scscr);
device->con->write = serial_console_write;
+ device->con->exit = early_console_exit;
+
return 0;
}
static int __init sci_early_console_setup(struct earlycon_device *device,
The patch below does not apply to the 6.13-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.13.y
git checkout FETCH_HEAD
git cherry-pick -x 5f1017069933489add0c08659673443c9905659e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025021028-ibuprofen-gnat-01d0@gregkh' --subject-prefix 'PATCH 6.13.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 5f1017069933489add0c08659673443c9905659e Mon Sep 17 00:00:00 2001
From: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Date: Thu, 16 Jan 2025 20:22:48 +0200
Subject: [PATCH] serial: sh-sci: Clean sci_ports[0] after at earlycon exit
The early_console_setup() function initializes sci_ports[0].port with an
object of type struct uart_port obtained from the struct earlycon_device
passed as an argument to early_console_setup().
Later, during serial port probing, the serial port used as earlycon
(e.g., port A) might be remapped to a different position in the sci_ports[]
array, and a different serial port (e.g., port B) might be assigned to slot
0. For example:
sci_ports[0] = port B
sci_ports[X] = port A
In this scenario, the new port mapped at index zero (port B) retains the
data associated with the earlycon configuration. Consequently, after the
Linux boot process, any access to the serial port now mapped to
sci_ports[0] (port B) will block the original earlycon port (port A).
To address this, introduce an early_console_exit() function to clean up
sci_ports[0] when earlycon is exited.
To prevent the cleanup of sci_ports[0] while the serial device is still
being used by earlycon, introduce the struct sci_port::probing flag and
account for it in early_console_exit().
Fixes: 0b0cced19ab1 ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Link: https://lore.kernel.org/r/20250116182249.3828577-5-claudiu.beznea.uj@bp.ren…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index b85a9d425f7e..e64d59888ecd 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -166,6 +166,7 @@ static struct sci_port sci_ports[SCI_NPORTS];
static unsigned long sci_ports_in_use;
static struct uart_driver sci_uart_driver;
static bool sci_uart_earlycon;
+static bool sci_uart_earlycon_dev_probing;
static inline struct sci_port *
to_sci_port(struct uart_port *uart)
@@ -3386,7 +3387,8 @@ static struct plat_sci_port *sci_parse_dt(struct platform_device *pdev,
static int sci_probe_single(struct platform_device *dev,
unsigned int index,
struct plat_sci_port *p,
- struct sci_port *sciport)
+ struct sci_port *sciport,
+ struct resource *sci_res)
{
int ret;
@@ -3433,6 +3435,14 @@ static int sci_probe_single(struct platform_device *dev,
sciport->port.flags |= UPF_HARD_FLOW;
}
+ if (sci_uart_earlycon && sci_ports[0].port.mapbase == sci_res->start) {
+ /*
+ * Skip cleanup the sci_port[0] in early_console_exit(), this
+ * port is the same as the earlycon one.
+ */
+ sci_uart_earlycon_dev_probing = true;
+ }
+
return uart_add_one_port(&sci_uart_driver, &sciport->port);
}
@@ -3491,7 +3501,7 @@ static int sci_probe(struct platform_device *dev)
platform_set_drvdata(dev, sp);
- ret = sci_probe_single(dev, dev_id, p, sp);
+ ret = sci_probe_single(dev, dev_id, p, sp, res);
if (ret)
return ret;
@@ -3574,6 +3584,22 @@ sh_early_platform_init_buffer("earlyprintk", &sci_driver,
#ifdef CONFIG_SERIAL_SH_SCI_EARLYCON
static struct plat_sci_port port_cfg;
+static int early_console_exit(struct console *co)
+{
+ struct sci_port *sci_port = &sci_ports[0];
+
+ /*
+ * Clean the slot used by earlycon. A new SCI device might
+ * map to this slot.
+ */
+ if (!sci_uart_earlycon_dev_probing) {
+ memset(sci_port, 0, sizeof(*sci_port));
+ sci_uart_earlycon = false;
+ }
+
+ return 0;
+}
+
static int __init early_console_setup(struct earlycon_device *device,
int type)
{
@@ -3591,6 +3617,8 @@ static int __init early_console_setup(struct earlycon_device *device,
SCSCR_RE | SCSCR_TE | port_cfg.scscr);
device->con->write = serial_console_write;
+ device->con->exit = early_console_exit;
+
return 0;
}
static int __init sci_early_console_setup(struct earlycon_device *device,
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 651dee03696e1dfde6d9a7e8664bbdcd9a10ea7f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025021024-stoop-renewed-a942@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 651dee03696e1dfde6d9a7e8664bbdcd9a10ea7f Mon Sep 17 00:00:00 2001
From: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Date: Thu, 16 Jan 2025 20:22:49 +0200
Subject: [PATCH] serial: sh-sci: Increment the runtime usage counter for the
earlycon device
In the sh-sci driver, serial ports are mapped to the sci_ports[] array,
with earlycon mapped at index zero.
The uart_add_one_port() function eventually calls __device_attach(),
which, in turn, calls pm_request_idle(). The identified code path is as
follows:
uart_add_one_port() ->
serial_ctrl_register_port() ->
serial_core_register_port() ->
serial_core_port_device_add() ->
serial_base_port_add() ->
device_add() ->
bus_probe_device() ->
device_initial_probe() ->
__device_attach() ->
// ...
if (dev->p->dead) {
// ...
} else if (dev->driver) {
// ...
} else {
// ...
pm_request_idle(dev);
// ...
}
The earlycon device clocks are enabled by the bootloader. However, the
pm_request_idle() call in __device_attach() disables the SCI port clocks
while earlycon is still active.
The earlycon write function, serial_console_write(), calls
sci_poll_put_char() via serial_console_putchar(). If the SCI port clocks
are disabled, writing to earlycon may sometimes cause the SR.TDFE bit to
remain unset indefinitely, causing the while loop in sci_poll_put_char()
to never exit. On single-core SoCs, this can result in the system being
blocked during boot when this issue occurs.
To resolve this, increment the runtime PM usage counter for the earlycon
SCI device before registering the UART port.
Fixes: 0b0cced19ab1 ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Link: https://lore.kernel.org/r/20250116182249.3828577-6-claudiu.beznea.uj@bp.ren…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index e64d59888ecd..b1ea48f38248 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -3436,6 +3436,22 @@ static int sci_probe_single(struct platform_device *dev,
}
if (sci_uart_earlycon && sci_ports[0].port.mapbase == sci_res->start) {
+ /*
+ * In case:
+ * - this is the earlycon port (mapped on index 0 in sci_ports[]) and
+ * - it now maps to an alias other than zero and
+ * - the earlycon is still alive (e.g., "earlycon keep_bootcon" is
+ * available in bootargs)
+ *
+ * we need to avoid disabling clocks and PM domains through the runtime
+ * PM APIs called in __device_attach(). For this, increment the runtime
+ * PM reference counter (the clocks and PM domains were already enabled
+ * by the bootloader). Otherwise the earlycon may access the HW when it
+ * has no clocks enabled leading to failures (infinite loop in
+ * sci_poll_put_char()).
+ */
+ pm_runtime_get_noresume(&dev->dev);
+
/*
* Skip cleanup the sci_port[0] in early_console_exit(), this
* port is the same as the earlycon one.
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 651dee03696e1dfde6d9a7e8664bbdcd9a10ea7f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025021018-eaten-speech-f2c6@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 651dee03696e1dfde6d9a7e8664bbdcd9a10ea7f Mon Sep 17 00:00:00 2001
From: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Date: Thu, 16 Jan 2025 20:22:49 +0200
Subject: [PATCH] serial: sh-sci: Increment the runtime usage counter for the
earlycon device
In the sh-sci driver, serial ports are mapped to the sci_ports[] array,
with earlycon mapped at index zero.
The uart_add_one_port() function eventually calls __device_attach(),
which, in turn, calls pm_request_idle(). The identified code path is as
follows:
uart_add_one_port() ->
serial_ctrl_register_port() ->
serial_core_register_port() ->
serial_core_port_device_add() ->
serial_base_port_add() ->
device_add() ->
bus_probe_device() ->
device_initial_probe() ->
__device_attach() ->
// ...
if (dev->p->dead) {
// ...
} else if (dev->driver) {
// ...
} else {
// ...
pm_request_idle(dev);
// ...
}
The earlycon device clocks are enabled by the bootloader. However, the
pm_request_idle() call in __device_attach() disables the SCI port clocks
while earlycon is still active.
The earlycon write function, serial_console_write(), calls
sci_poll_put_char() via serial_console_putchar(). If the SCI port clocks
are disabled, writing to earlycon may sometimes cause the SR.TDFE bit to
remain unset indefinitely, causing the while loop in sci_poll_put_char()
to never exit. On single-core SoCs, this can result in the system being
blocked during boot when this issue occurs.
To resolve this, increment the runtime PM usage counter for the earlycon
SCI device before registering the UART port.
Fixes: 0b0cced19ab1 ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Link: https://lore.kernel.org/r/20250116182249.3828577-6-claudiu.beznea.uj@bp.ren…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index e64d59888ecd..b1ea48f38248 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -3436,6 +3436,22 @@ static int sci_probe_single(struct platform_device *dev,
}
if (sci_uart_earlycon && sci_ports[0].port.mapbase == sci_res->start) {
+ /*
+ * In case:
+ * - this is the earlycon port (mapped on index 0 in sci_ports[]) and
+ * - it now maps to an alias other than zero and
+ * - the earlycon is still alive (e.g., "earlycon keep_bootcon" is
+ * available in bootargs)
+ *
+ * we need to avoid disabling clocks and PM domains through the runtime
+ * PM APIs called in __device_attach(). For this, increment the runtime
+ * PM reference counter (the clocks and PM domains were already enabled
+ * by the bootloader). Otherwise the earlycon may access the HW when it
+ * has no clocks enabled leading to failures (infinite loop in
+ * sci_poll_put_char()).
+ */
+ pm_runtime_get_noresume(&dev->dev);
+
/*
* Skip cleanup the sci_port[0] in early_console_exit(), this
* port is the same as the earlycon one.
The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 651dee03696e1dfde6d9a7e8664bbdcd9a10ea7f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025021018-cultural-gossip-22ea@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 651dee03696e1dfde6d9a7e8664bbdcd9a10ea7f Mon Sep 17 00:00:00 2001
From: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Date: Thu, 16 Jan 2025 20:22:49 +0200
Subject: [PATCH] serial: sh-sci: Increment the runtime usage counter for the
earlycon device
In the sh-sci driver, serial ports are mapped to the sci_ports[] array,
with earlycon mapped at index zero.
The uart_add_one_port() function eventually calls __device_attach(),
which, in turn, calls pm_request_idle(). The identified code path is as
follows:
uart_add_one_port() ->
serial_ctrl_register_port() ->
serial_core_register_port() ->
serial_core_port_device_add() ->
serial_base_port_add() ->
device_add() ->
bus_probe_device() ->
device_initial_probe() ->
__device_attach() ->
// ...
if (dev->p->dead) {
// ...
} else if (dev->driver) {
// ...
} else {
// ...
pm_request_idle(dev);
// ...
}
The earlycon device clocks are enabled by the bootloader. However, the
pm_request_idle() call in __device_attach() disables the SCI port clocks
while earlycon is still active.
The earlycon write function, serial_console_write(), calls
sci_poll_put_char() via serial_console_putchar(). If the SCI port clocks
are disabled, writing to earlycon may sometimes cause the SR.TDFE bit to
remain unset indefinitely, causing the while loop in sci_poll_put_char()
to never exit. On single-core SoCs, this can result in the system being
blocked during boot when this issue occurs.
To resolve this, increment the runtime PM usage counter for the earlycon
SCI device before registering the UART port.
Fixes: 0b0cced19ab1 ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Link: https://lore.kernel.org/r/20250116182249.3828577-6-claudiu.beznea.uj@bp.ren…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index e64d59888ecd..b1ea48f38248 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -3436,6 +3436,22 @@ static int sci_probe_single(struct platform_device *dev,
}
if (sci_uart_earlycon && sci_ports[0].port.mapbase == sci_res->start) {
+ /*
+ * In case:
+ * - this is the earlycon port (mapped on index 0 in sci_ports[]) and
+ * - it now maps to an alias other than zero and
+ * - the earlycon is still alive (e.g., "earlycon keep_bootcon" is
+ * available in bootargs)
+ *
+ * we need to avoid disabling clocks and PM domains through the runtime
+ * PM APIs called in __device_attach(). For this, increment the runtime
+ * PM reference counter (the clocks and PM domains were already enabled
+ * by the bootloader). Otherwise the earlycon may access the HW when it
+ * has no clocks enabled leading to failures (infinite loop in
+ * sci_poll_put_char()).
+ */
+ pm_runtime_get_noresume(&dev->dev);
+
/*
* Skip cleanup the sci_port[0] in early_console_exit(), this
* port is the same as the earlycon one.
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 651dee03696e1dfde6d9a7e8664bbdcd9a10ea7f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025021017-turbulent-unpopular-11f3@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 651dee03696e1dfde6d9a7e8664bbdcd9a10ea7f Mon Sep 17 00:00:00 2001
From: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Date: Thu, 16 Jan 2025 20:22:49 +0200
Subject: [PATCH] serial: sh-sci: Increment the runtime usage counter for the
earlycon device
In the sh-sci driver, serial ports are mapped to the sci_ports[] array,
with earlycon mapped at index zero.
The uart_add_one_port() function eventually calls __device_attach(),
which, in turn, calls pm_request_idle(). The identified code path is as
follows:
uart_add_one_port() ->
serial_ctrl_register_port() ->
serial_core_register_port() ->
serial_core_port_device_add() ->
serial_base_port_add() ->
device_add() ->
bus_probe_device() ->
device_initial_probe() ->
__device_attach() ->
// ...
if (dev->p->dead) {
// ...
} else if (dev->driver) {
// ...
} else {
// ...
pm_request_idle(dev);
// ...
}
The earlycon device clocks are enabled by the bootloader. However, the
pm_request_idle() call in __device_attach() disables the SCI port clocks
while earlycon is still active.
The earlycon write function, serial_console_write(), calls
sci_poll_put_char() via serial_console_putchar(). If the SCI port clocks
are disabled, writing to earlycon may sometimes cause the SR.TDFE bit to
remain unset indefinitely, causing the while loop in sci_poll_put_char()
to never exit. On single-core SoCs, this can result in the system being
blocked during boot when this issue occurs.
To resolve this, increment the runtime PM usage counter for the earlycon
SCI device before registering the UART port.
Fixes: 0b0cced19ab1 ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Link: https://lore.kernel.org/r/20250116182249.3828577-6-claudiu.beznea.uj@bp.ren…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index e64d59888ecd..b1ea48f38248 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -3436,6 +3436,22 @@ static int sci_probe_single(struct platform_device *dev,
}
if (sci_uart_earlycon && sci_ports[0].port.mapbase == sci_res->start) {
+ /*
+ * In case:
+ * - this is the earlycon port (mapped on index 0 in sci_ports[]) and
+ * - it now maps to an alias other than zero and
+ * - the earlycon is still alive (e.g., "earlycon keep_bootcon" is
+ * available in bootargs)
+ *
+ * we need to avoid disabling clocks and PM domains through the runtime
+ * PM APIs called in __device_attach(). For this, increment the runtime
+ * PM reference counter (the clocks and PM domains were already enabled
+ * by the bootloader). Otherwise the earlycon may access the HW when it
+ * has no clocks enabled leading to failures (infinite loop in
+ * sci_poll_put_char()).
+ */
+ pm_runtime_get_noresume(&dev->dev);
+
/*
* Skip cleanup the sci_port[0] in early_console_exit(), this
* port is the same as the earlycon one.
The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 651dee03696e1dfde6d9a7e8664bbdcd9a10ea7f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025021016-jackknife-duplicity-3312@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 651dee03696e1dfde6d9a7e8664bbdcd9a10ea7f Mon Sep 17 00:00:00 2001
From: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Date: Thu, 16 Jan 2025 20:22:49 +0200
Subject: [PATCH] serial: sh-sci: Increment the runtime usage counter for the
earlycon device
In the sh-sci driver, serial ports are mapped to the sci_ports[] array,
with earlycon mapped at index zero.
The uart_add_one_port() function eventually calls __device_attach(),
which, in turn, calls pm_request_idle(). The identified code path is as
follows:
uart_add_one_port() ->
serial_ctrl_register_port() ->
serial_core_register_port() ->
serial_core_port_device_add() ->
serial_base_port_add() ->
device_add() ->
bus_probe_device() ->
device_initial_probe() ->
__device_attach() ->
// ...
if (dev->p->dead) {
// ...
} else if (dev->driver) {
// ...
} else {
// ...
pm_request_idle(dev);
// ...
}
The earlycon device clocks are enabled by the bootloader. However, the
pm_request_idle() call in __device_attach() disables the SCI port clocks
while earlycon is still active.
The earlycon write function, serial_console_write(), calls
sci_poll_put_char() via serial_console_putchar(). If the SCI port clocks
are disabled, writing to earlycon may sometimes cause the SR.TDFE bit to
remain unset indefinitely, causing the while loop in sci_poll_put_char()
to never exit. On single-core SoCs, this can result in the system being
blocked during boot when this issue occurs.
To resolve this, increment the runtime PM usage counter for the earlycon
SCI device before registering the UART port.
Fixes: 0b0cced19ab1 ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Link: https://lore.kernel.org/r/20250116182249.3828577-6-claudiu.beznea.uj@bp.ren…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index e64d59888ecd..b1ea48f38248 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -3436,6 +3436,22 @@ static int sci_probe_single(struct platform_device *dev,
}
if (sci_uart_earlycon && sci_ports[0].port.mapbase == sci_res->start) {
+ /*
+ * In case:
+ * - this is the earlycon port (mapped on index 0 in sci_ports[]) and
+ * - it now maps to an alias other than zero and
+ * - the earlycon is still alive (e.g., "earlycon keep_bootcon" is
+ * available in bootargs)
+ *
+ * we need to avoid disabling clocks and PM domains through the runtime
+ * PM APIs called in __device_attach(). For this, increment the runtime
+ * PM reference counter (the clocks and PM domains were already enabled
+ * by the bootloader). Otherwise the earlycon may access the HW when it
+ * has no clocks enabled leading to failures (infinite loop in
+ * sci_poll_put_char()).
+ */
+ pm_runtime_get_noresume(&dev->dev);
+
/*
* Skip cleanup the sci_port[0] in early_console_exit(), this
* port is the same as the earlycon one.
The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 651dee03696e1dfde6d9a7e8664bbdcd9a10ea7f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025021015-endowment-ungraded-dbc0@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 651dee03696e1dfde6d9a7e8664bbdcd9a10ea7f Mon Sep 17 00:00:00 2001
From: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Date: Thu, 16 Jan 2025 20:22:49 +0200
Subject: [PATCH] serial: sh-sci: Increment the runtime usage counter for the
earlycon device
In the sh-sci driver, serial ports are mapped to the sci_ports[] array,
with earlycon mapped at index zero.
The uart_add_one_port() function eventually calls __device_attach(),
which, in turn, calls pm_request_idle(). The identified code path is as
follows:
uart_add_one_port() ->
serial_ctrl_register_port() ->
serial_core_register_port() ->
serial_core_port_device_add() ->
serial_base_port_add() ->
device_add() ->
bus_probe_device() ->
device_initial_probe() ->
__device_attach() ->
// ...
if (dev->p->dead) {
// ...
} else if (dev->driver) {
// ...
} else {
// ...
pm_request_idle(dev);
// ...
}
The earlycon device clocks are enabled by the bootloader. However, the
pm_request_idle() call in __device_attach() disables the SCI port clocks
while earlycon is still active.
The earlycon write function, serial_console_write(), calls
sci_poll_put_char() via serial_console_putchar(). If the SCI port clocks
are disabled, writing to earlycon may sometimes cause the SR.TDFE bit to
remain unset indefinitely, causing the while loop in sci_poll_put_char()
to never exit. On single-core SoCs, this can result in the system being
blocked during boot when this issue occurs.
To resolve this, increment the runtime PM usage counter for the earlycon
SCI device before registering the UART port.
Fixes: 0b0cced19ab1 ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Link: https://lore.kernel.org/r/20250116182249.3828577-6-claudiu.beznea.uj@bp.ren…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index e64d59888ecd..b1ea48f38248 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -3436,6 +3436,22 @@ static int sci_probe_single(struct platform_device *dev,
}
if (sci_uart_earlycon && sci_ports[0].port.mapbase == sci_res->start) {
+ /*
+ * In case:
+ * - this is the earlycon port (mapped on index 0 in sci_ports[]) and
+ * - it now maps to an alias other than zero and
+ * - the earlycon is still alive (e.g., "earlycon keep_bootcon" is
+ * available in bootargs)
+ *
+ * we need to avoid disabling clocks and PM domains through the runtime
+ * PM APIs called in __device_attach(). For this, increment the runtime
+ * PM reference counter (the clocks and PM domains were already enabled
+ * by the bootloader). Otherwise the earlycon may access the HW when it
+ * has no clocks enabled leading to failures (infinite loop in
+ * sci_poll_put_char()).
+ */
+ pm_runtime_get_noresume(&dev->dev);
+
/*
* Skip cleanup the sci_port[0] in early_console_exit(), this
* port is the same as the earlycon one.
The patch below does not apply to the 6.13-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.13.y
git checkout FETCH_HEAD
git cherry-pick -x 651dee03696e1dfde6d9a7e8664bbdcd9a10ea7f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025021014-overrule-trimmer-2e06@gregkh' --subject-prefix 'PATCH 6.13.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 651dee03696e1dfde6d9a7e8664bbdcd9a10ea7f Mon Sep 17 00:00:00 2001
From: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Date: Thu, 16 Jan 2025 20:22:49 +0200
Subject: [PATCH] serial: sh-sci: Increment the runtime usage counter for the
earlycon device
In the sh-sci driver, serial ports are mapped to the sci_ports[] array,
with earlycon mapped at index zero.
The uart_add_one_port() function eventually calls __device_attach(),
which, in turn, calls pm_request_idle(). The identified code path is as
follows:
uart_add_one_port() ->
serial_ctrl_register_port() ->
serial_core_register_port() ->
serial_core_port_device_add() ->
serial_base_port_add() ->
device_add() ->
bus_probe_device() ->
device_initial_probe() ->
__device_attach() ->
// ...
if (dev->p->dead) {
// ...
} else if (dev->driver) {
// ...
} else {
// ...
pm_request_idle(dev);
// ...
}
The earlycon device clocks are enabled by the bootloader. However, the
pm_request_idle() call in __device_attach() disables the SCI port clocks
while earlycon is still active.
The earlycon write function, serial_console_write(), calls
sci_poll_put_char() via serial_console_putchar(). If the SCI port clocks
are disabled, writing to earlycon may sometimes cause the SR.TDFE bit to
remain unset indefinitely, causing the while loop in sci_poll_put_char()
to never exit. On single-core SoCs, this can result in the system being
blocked during boot when this issue occurs.
To resolve this, increment the runtime PM usage counter for the earlycon
SCI device before registering the UART port.
Fixes: 0b0cced19ab1 ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj(a)bp.renesas.com>
Link: https://lore.kernel.org/r/20250116182249.3828577-6-claudiu.beznea.uj@bp.ren…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index e64d59888ecd..b1ea48f38248 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -3436,6 +3436,22 @@ static int sci_probe_single(struct platform_device *dev,
}
if (sci_uart_earlycon && sci_ports[0].port.mapbase == sci_res->start) {
+ /*
+ * In case:
+ * - this is the earlycon port (mapped on index 0 in sci_ports[]) and
+ * - it now maps to an alias other than zero and
+ * - the earlycon is still alive (e.g., "earlycon keep_bootcon" is
+ * available in bootargs)
+ *
+ * we need to avoid disabling clocks and PM domains through the runtime
+ * PM APIs called in __device_attach(). For this, increment the runtime
+ * PM reference counter (the clocks and PM domains were already enabled
+ * by the bootloader). Otherwise the earlycon may access the HW when it
+ * has no clocks enabled leading to failures (infinite loop in
+ * sci_poll_put_char()).
+ */
+ pm_runtime_get_noresume(&dev->dev);
+
/*
* Skip cleanup the sci_port[0] in early_console_exit(), this
* port is the same as the earlycon one.
The iopf_queue_remove_device() helper removes a device from the per-iommu
iopf queue when PRI is disabled on the device. It responds to all
outstanding iopf's with an IOMMU_PAGE_RESP_INVALID code and detaches the
device from the queue.
However, it fails to release the group structure that represents a group
of iopf's awaiting for a response after responding to the hardware. This
can cause a memory leak if iopf_queue_remove_device() is called with
pending iopf's.
Fix it by calling iopf_free_group() after the iopf group is responded.
Fixes: 199112327135 ("iommu: Track iopf group instead of last fault")
Cc: stable(a)vger.kernel.org
Suggested-by: Kevin Tian <kevin.tian(a)intel.com>
Signed-off-by: Lu Baolu <baolu.lu(a)linux.intel.com>
---
drivers/iommu/io-pgfault.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c
index 4674e618797c..8b5926c1452e 100644
--- a/drivers/iommu/io-pgfault.c
+++ b/drivers/iommu/io-pgfault.c
@@ -478,6 +478,7 @@ void iopf_queue_remove_device(struct iopf_queue *queue, struct device *dev)
ops->page_response(dev, iopf, &resp);
list_del_init(&group->pending_node);
+ iopf_free_group(group);
}
mutex_unlock(&fault_param->lock);
--
2.43.0