We are seeing start_tx being called after port shutdown as noted by Jiri.
This happens because we are missing the startup and shutdown related
functions for the serial base port.
Let's fix the issue by adding startup and shutdown functions for the
serial base port to block tx flushing for the serial base port when the
port is not in use.
Fixes: 84a9582fd2 ("serial: core: Start managing serial controllers to enable runtime PM")
Cc: stable <stable@kernel.org>
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20240411055848.38190-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The circular buffer is NULLified in uart_tty_port_shutdown()
under the spin lock. However, the PM or other timer based callbacks
may still trigger after this event without knowning that buffer pointer
is not valid. Since the serial code is a bit inconsistent in checking
the buffer state (some rely on the head-tail positions, some on the
buffer pointer), it's better to have both aligned, i.e. buffer pointer
to be NULL and head-tail possitions to be the same, meaning it's empty.
This will prevent asynchronous calls to dereference NULL pointer as
reported recently in 8250 case:
BUG: kernel NULL pointer dereference, address: 00000cf5
Workqueue: pm pm_runtime_work
EIP: serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809)
...
? serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809)
__start_tx (drivers/tty/serial/8250/8250_port.c:1551)
serial8250_start_tx (drivers/tty/serial/8250/8250_port.c:1654)
serial_port_runtime_suspend (include/linux/serial_core.h:667 drivers/tty/serial/serial_port.c:63)
__rpm_callback (drivers/base/power/runtime.c:393)
? serial_port_remove (drivers/tty/serial/serial_port.c:50)
rpm_suspend (drivers/base/power/runtime.c:447)
The proposed change will prevent ->start_tx() to be called during
suspend on shut down port.
Fixes: 43066e3222 ("serial: port: Don't suspend if the port is still busy")
Cc: stable <stable@kernel.org>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202404031607.2e92eebe-lkp@intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240404150034.41648-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The uart_handle_cts_change() function in serial_core expects the caller
to hold uport->lock. For example, I have seen the below kernel splat,
when the Bluetooth driver is loaded on an i.MX28 board.
[ 85.119255] ------------[ cut here ]------------
[ 85.124413] WARNING: CPU: 0 PID: 27 at /drivers/tty/serial/serial_core.c:3453 uart_handle_cts_change+0xb4/0xec
[ 85.134694] Modules linked in: hci_uart bluetooth ecdh_generic ecc wlcore_sdio configfs
[ 85.143314] CPU: 0 PID: 27 Comm: kworker/u3:0 Not tainted 6.6.3-00021-gd62a2f068f92 #1
[ 85.151396] Hardware name: Freescale MXS (Device Tree)
[ 85.156679] Workqueue: hci0 hci_power_on [bluetooth]
(...)
[ 85.191765] uart_handle_cts_change from mxs_auart_irq_handle+0x380/0x3f4
[ 85.198787] mxs_auart_irq_handle from __handle_irq_event_percpu+0x88/0x210
(...)
Cc: stable@vger.kernel.org
Fixes: 4d90bb147e ("serial: core: Document and assert lock requirements for irq helpers")
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Emil Kronborg <emil.kronborg@protonmail.com>
Link: https://lore.kernel.org/r/20240320121530.11348-1-emil.kronborg@protonmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit e5d6bd25f9 ("serial: 8250_dw: Do not reclock if already at
correct rate") breaks the dw UARTs on Intel Bay Trail (BYT) and
Cherry Trail (CHT) SoCs.
Before this change the RTL8732BS Bluetooth HCI which is found
connected over the dw UART on both BYT and CHT boards works properly:
Bluetooth: hci0: RTL: examining hci_ver=06 hci_rev=000b lmp_ver=06 lmp_subver=8723
Bluetooth: hci0: RTL: rom_version status=0 version=1
Bluetooth: hci0: RTL: loading rtl_bt/rtl8723bs_fw.bin
Bluetooth: hci0: RTL: loading rtl_bt/rtl8723bs_config-OBDA8723.bin
Bluetooth: hci0: RTL: cfg_sz 64, total sz 24508
Bluetooth: hci0: RTL: fw version 0x365d462e
where as after this change probing it fails:
Bluetooth: hci0: RTL: examining hci_ver=06 hci_rev=000b lmp_ver=06 lmp_subver=8723
Bluetooth: hci0: RTL: rom_version status=0 version=1
Bluetooth: hci0: RTL: loading rtl_bt/rtl8723bs_fw.bin
Bluetooth: hci0: RTL: loading rtl_bt/rtl8723bs_config-OBDA8723.bin
Bluetooth: hci0: RTL: cfg_sz 64, total sz 24508
Bluetooth: hci0: command 0xfc20 tx timeout
Bluetooth: hci0: RTL: download fw command failed (-110)
Revert the changes to fix this regression.
Fixes: e5d6bd25f9 ("serial: 8250_dw: Do not reclock if already at correct rate")
Cc: stable@vger.kernel.org
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Peter Collingbourne <pcc@google.com>
Link: https://lore.kernel.org/r/20240317214123.34482-1-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull tty / serial driver updates from Greg KH:
"Here is the big set of TTY/Serial driver updates and cleanups for
6.9-rc1. Included in here are:
- more tty cleanups from Jiri
- loads of 8250 driver cleanups from Andy
- max310x driver updates
- samsung serial driver updates
- uart_prepare_sysrq_char() updates for many drivers
- platform driver remove callback void cleanups
- stm32 driver updates
- other small tty/serial driver updates
All of these have been in linux-next for a long time with no reported
issues"
* tag 'tty-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (199 commits)
dt-bindings: serial: stm32: add power-domains property
serial: 8250_dw: Replace ACPI device check by a quirk
serial: Lock console when calling into driver before registration
serial: 8250_uniphier: Switch to use uart_read_port_properties()
serial: 8250_tegra: Switch to use uart_read_port_properties()
serial: 8250_pxa: Switch to use uart_read_port_properties()
serial: 8250_omap: Switch to use uart_read_port_properties()
serial: 8250_of: Switch to use uart_read_port_properties()
serial: 8250_lpc18xx: Switch to use uart_read_port_properties()
serial: 8250_ingenic: Switch to use uart_read_port_properties()
serial: 8250_dw: Switch to use uart_read_port_properties()
serial: 8250_bcm7271: Switch to use uart_read_port_properties()
serial: 8250_bcm2835aux: Switch to use uart_read_port_properties()
serial: 8250_aspeed_vuart: Switch to use uart_read_port_properties()
serial: port: Introduce a common helper to read properties
serial: core: Add UPIO_UNKNOWN constant for unknown port type
serial: core: Move struct uart_port::quirks closer to possible values
serial: sh-sci: Call sci_serial_{in,out}() directly
serial: core: only stop transmit when HW fifo is empty
serial: pch: Use uart_prepare_sysrq_char().
...
Pull powerpc updates from Michael Ellerman:
- Add AT_HWCAP3 and AT_HWCAP4 aux vector entries for future use
by glibc
- Add support for recognising the Power11 architected and raw PVRs
- Add support for nr_cpus=n on the command line where the
boot CPU is >= n
- Add ppcxx_allmodconfig targets for all 32-bit sub-arches
- Other small features, cleanups and fixes
Thanks to Akanksha J N, Brian King, Christophe Leroy, Dawei Li, Geoff
Levand, Greg Kroah-Hartman, Jan-Benedict Glaw, Kajol Jain, Kunwu Chan,
Li zeming, Madhavan Srinivasan, Masahiro Yamada, Nathan Chancellor,
Nicholas Piggin, Peter Bergner, Qiheng Lin, Randy Dunlap, Ricardo B.
Marliere, Rob Herring, Sathvika Vasireddy, Shrikanth Hegde, Uwe
Kleine-König, Vaibhav Jain, and Wen Xiong.
* tag 'powerpc-6.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (71 commits)
powerpc/macio: Make remove callback of macio driver void returned
powerpc/83xx: Fix build failure with FPU=n
powerpc/64s: Fix get_hugepd_cache_index() build failure
powerpc/4xx: Fix warp_gpio_leds build failure
powerpc/amigaone: Make several functions static
powerpc/embedded6xx: Fix no previous prototype for avr_uart_send() etc.
macintosh/adb: make adb_dev_class constant
powerpc: xor_vmx: Add '-mhard-float' to CFLAGS
powerpc/fsl: Fix mfpmr() asm constraint error
powerpc: Remove cpu-as-y completely
powerpc/fsl: Modernise mt/mfpmr
powerpc/fsl: Fix mfpmr build errors with newer binutils
powerpc/64s: Use .machine power4 around dcbt
powerpc/64s: Move dcbt/dcbtst sequence into a macro
powerpc/mm: Code cleanup for __hash_page_thp
powerpc/hv-gpci: Fix the H_GET_PERF_COUNTER_INFO hcall return value checks
powerpc/irq: Allow softirq to hardirq stack transition
powerpc: Stop using of_root
powerpc/machdep: Define 'compatibles' property in ppc_md and use it
of: Reimplement of_machine_is_compatible() using of_machine_compatible_match()
...
This reverts commit 5c7e105cd1.
As identified by KASAN, the simplification done by the cleanup patch
was not legal.
>From tracing through the code, it can be seen that we're transmitting
from a 4096-byte circular buffer. We copy anywhere from 1-4 bytes from
it each time. The simplification runs into trouble when we get near
the end of the circular buffer. For instance, we might start out with
xmit->tail = 4094 and we want to transfer 4 bytes. With the code
before simplification this was no problem. We'd read buf[4094],
buf[4095], buf[0], and buf[1]. With the new code we'll do a
memcpy(&buf[4094], 4) which reads 2 bytes past the end of the buffer
and then skips transmitting what's at buf[0] and buf[1].
KASAN isn't 100% consistent at reporting this for me, but to be extra
confident in the analysis, I added traces of the tail and tx_bytes and
then wrote a test program:
while true; do
echo -n "abcdefghijklmnopqrstuvwxyz0" > /dev/ttyMSM0
sleep .1
done
I watched the traces over SSH and saw:
qcom_geni_serial_send_chunk_fifo: 4093 4
qcom_geni_serial_send_chunk_fifo: 1 3
Which indicated that one byte should be missing. Sure enough the
output that should have been:
abcdefghijklmnopqrstuvwxyz0
In one case was actually missing a byte:
abcdefghijklmnopqrstuvwyz0
Running "ls -al" on large directories also made the missing bytes
obvious since columns didn't line up.
While the original code may not be the most elegant, we only talking
about copying up to 4 bytes here. Let's just go back to the code that
worked.
Fixes: 5c7e105cd1 ("tty: serial: simplify qcom_geni_serial_send_chunk_fifo()")
Cc: stable <stable@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Jiri Slaby <jirislaby@kernel.org>
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20240304174952.1.I920a314049b345efd1f69d708e7f74d2213d0b49@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the remote uart device is not connected or not enabled after booting
up, the CTS line is high by default. At this time, if we enable the flow
control when opening the device(for example, using “stty -F /dev/ttyLP4
crtscts” command), there will be a pending idle preamble(first writing 0
and then writing 1 to UARTCTRL_TE will queue an idle preamble) that
cannot be sent out, resulting in the uart port fail to close(waiting for
TX empty), so the user space stty will have to wait for a long time or
forever.
This is an LPUART IP bug(idle preamble has higher priority than CTS),
here add a workaround patch to enable TX CTS after enabling UARTCTRL_TE,
so that the idle preamble does not get stuck due to CTS is deasserted.
Fixes: 380c966c09 ("tty: serial: fsl_lpuart: add 32-bit register interface support")
Cc: stable <stable@kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Link: https://lore.kernel.org/r/20240305015706.1050769-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
During the handoff from earlycon to the real console driver, we have
two separate drivers operating on the same device concurrently. In the
case of the 8250 driver these concurrent accesses cause problems due
to the driver's use of banked registers, controlled by LCR.DLAB. It is
possible for the setup(), config_port(), pm() and set_mctrl() callbacks
to set DLAB, which can cause the earlycon code that intends to access
TX to instead access DLL, leading to missed output and corruption on
the serial line due to unintended modifications to the baud rate.
In particular, for setup() we have:
univ8250_console_setup()
-> serial8250_console_setup()
-> uart_set_options()
-> serial8250_set_termios()
-> serial8250_do_set_termios()
-> serial8250_do_set_divisor()
For config_port() we have:
serial8250_config_port()
-> autoconfig()
For pm() we have:
serial8250_pm()
-> serial8250_do_pm()
-> serial8250_set_sleep()
For set_mctrl() we have (for some devices):
serial8250_set_mctrl()
-> omap8250_set_mctrl()
-> __omap8250_set_mctrl()
To avoid such problems, let's make it so that the console is locked
during pre-registration calls to these callbacks, which will prevent
the earlycon driver from running concurrently.
Remove the partial solution to this problem in the 8250 driver
that locked the console only during autoconfig_irq(), as this would
result in a deadlock with the new approach. The console continues
to be locked during autoconfig_irq() because it can only be called
through uart_configure_port().
Although this patch introduces more locking than strictly necessary
(and in particular it also locks during the call to rs485_config()
which is not affected by this issue as far as I can tell), it follows
the principle that it is the responsibility of the generic console
code to manage the earlycon handoff by ensuring that earlycon and real
console driver code cannot run concurrently, and not the individual
drivers.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://linux-review.googlesource.com/id/I7cf8124dcebf8618e6b2ee543fa5b25532de55d8
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240304214350.501253-1-pcc@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Unlike the 8250 serial driver complex, the sh-sci driver uses only a
single pair of functions to read and write serial port registers.
Hence there is no need to incur the overhead of calling them through
indirection, like the serial_port_{in,out}() wrappers do.
Replace all calls to these wrappers by direct calls to
sci_serial_{in,out}().
Remove the setup of the uart_port.serial_{in,out}() callbacks. After
removal of all calls to serial_port_{in,out}() in the sh-sci driver, the
only remaining user is uart_xchar_out(), which the sh-sci driver does
not use.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: https://lore.kernel.org/r/51e79d601cb9d9d63822d3773d3cf05a96868612.1709548811.git.geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We accidently met the issue that the bash prompt is not shown after the
previous command done and until the next input if there's only one CPU
(In our issue other CPUs are isolated by isolcpus=). Further analysis
shows it's because the port entering runtime suspend even if there's
still pending chars in the buffer and the pending chars will only be
processed in next device resuming. We are using amba-pl011 and the
problematic flow is like below:
Bash kworker
tty_write()
file_tty_write()
n_tty_write()
uart_write()
__uart_start()
pm_runtime_get() // wakeup waker
queue_work()
pm_runtime_work()
rpm_resume()
status = RPM_RESUMING
serial_port_runtime_resume()
port->ops->start_tx()
pl011_tx_chars()
uart_write_wakeup()
[…]
__uart_start()
pm_runtime_get() < 0 // because runtime status = RPM_RESUMING
// later data are not commit to the port driver
status = RPM_ACTIVE
rpm_idle() -> rpm_suspend()
This patch tries to fix this by checking the port busy before entering
runtime suspending. A runtime_suspend callback is added for the port
driver. When entering runtime suspend the callback is invoked, if there's
still pending chars in the buffer then flush the buffer.
Fixes: 84a9582fd2 ("serial: core: Start managing serial controllers to enable runtime PM")
Cc: stable <stable@kernel.org>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/20240226152351.40924-1-yangyicong@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When userspace opens the console, we call set_termios() passing a
termios with the console's configured baud rate. Currently this causes
dw8250_set_termios() to disable and then re-enable the UART clock at
the same frequency as it was originally. This can cause corruption
of any concurrent console output. Fix it by skipping the reclocking
if we are already at the correct rate.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Fixes: 4e26b134bd ("serial: 8250_dw: clock rate handling for all ACPI platforms")
Cc: stable@vger.kernel.org
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240222192635.1050502-1-pcc@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When about to transmit the function imx_uart_start_tx is called and in
some RS485 configurations this function will call imx_uart_stop_rx. The
problem is that imx_uart_stop_rx will enable loopback in order to
release the RS485 bus, but when loopback is enabled transmitted data
will just be looped to RX.
This patch fixes the above problem by not enabling loopback when about
to transmit.
This driver now works well when used for RS485 half duplex master
configurations.
Fixes: 79d0224f6b ("tty: serial: imx: Handle RS485 DE signal active high")
Cc: stable <stable@kernel.org>
Signed-off-by: Rickard x Andersson <rickaran@axis.com>
Tested-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Link: https://lore.kernel.org/r/20240221115304.509811-1-rickaran@axis.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.
Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-19-bigeasy@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The struct eg20t_port has a spinlock_t which is used for locking while
access I/O of the device. Then there is the uart_portlock which is
sometimes and nests within eg20t_port's lock.
The uart_port lock is not used while using the struct in
pch_uart_hal_read() which might be okay. Then both locks are used in
pch_console_write() which looks odd especially the double try_lock part.
All in all it looks like the uart_port's lock could replace eg20t_port's
lock and simplify the code.
Remove eg20t_port::lock and use uart_port's lock for the lock scope.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-18-bigeasy@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.
Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.
Cc: Hammer Hsieh <hammerh0314@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-9-bigeasy@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.
Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-8-bigeasy@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.
Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-7-bigeasy@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.
Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-4-bigeasy@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.
Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-3-bigeasy@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
