linux-stable.git/drivers/tty, branch v6.1.136 Linux kernel stable tree serial: sifive: lock port in startup()/shutdown() callbacks 2025-05-02T05:46:58+00:00 Ryo Takakura ryotkkr98@gmail.com 2025-04-12T00:18:47+00:00 fd93c803f21a1a0bdbabc4b99befc450c1d2ba24 commit e1ca3ff28ab1e2c1e70713ef3fa7943c725742c3 upstream. 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. Fixes: 45c054d0815b ("tty: serial: add driver for the SiFive UART") Signed-off-by: Ryo Takakura <ryotkkr98@gmail.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Cc: stable@vger.kernel.org Reviewed-by: John Ogness <john.ogness@linutronix.de> Rule: add Link: https://lore.kernel.org/stable/20250330003522.386632-1-ryotkkr98%40gmail.com Link: https://lore.kernel.org/r/20250412001847.183221-1-ryotkkr98@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e1ca3ff28ab1e2c1e70713ef3fa7943c725742c3 upstream.

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.

Fixes: 45c054d0815b ("tty: serial: add driver for the SiFive UART")
Signed-off-by: Ryo Takakura <ryotkkr98@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Rule: add
Link: https://lore.kernel.org/stable/20250330003522.386632-1-ryotkkr98%40gmail.com
Link: https://lore.kernel.org/r/20250412001847.183221-1-ryotkkr98@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: msm: Configure correct working mode before starting earlycon 2025-05-02T05:46:58+00:00 Stephan Gerhold stephan.gerhold@linaro.org 2025-04-08T17:22:47+00:00 1adf7a11659258bb4db9f83eea367dd9bd00c97b commit 7094832b5ac861b0bd7ed8866c93cb15ef619996 upstream. The MSM UART DM controller supports different working modes, e.g. DMA or the "single-character mode", where all reads/writes operate on a single character rather than 4 chars (32-bit) at once. When using earlycon, __msm_console_write() always writes 4 characters at a time, but we don't know which mode the bootloader was using and we don't set the mode either. This causes garbled output if the bootloader was using the single-character mode, because only every 4th character appears in the serial console, e.g. "[ 00oni pi 000xf0[ 00i s 5rm9(l)l s 1 1 SPMTA 7:C 5[ 00A ade k d[ 00ano:ameoi .Q1B[ 00ac _idaM00080oo'" If the bootloader was using the DMA ("DM") mode, output would likely fail entirely. Later, when the full serial driver probes, the port is re-initialized and output works as expected. Fix this also for earlycon by clearing the DMEN register and reset+re-enable the transmitter to apply the change. This ensures the transmitter is in the expected state before writing any output. Cc: stable <stable@kernel.org> Fixes: 0efe72963409 ("tty: serial: msm: Add earlycon support") Signed-off-by: Stephan Gerhold <stephan.gerhold@linaro.org> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org> Link: https://lore.kernel.org/r/20250408-msm-serial-earlycon-v1-1-429080127530@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 7094832b5ac861b0bd7ed8866c93cb15ef619996 upstream.

The MSM UART DM controller supports different working modes, e.g. DMA or
the "single-character mode", where all reads/writes operate on a single
character rather than 4 chars (32-bit) at once. When using earlycon,
__msm_console_write() always writes 4 characters at a time, but we don't
know which mode the bootloader was using and we don't set the mode either.

This causes garbled output if the bootloader was using the single-character
mode, because only every 4th character appears in the serial console, e.g.

  "[ 00oni pi  000xf0[ 00i s 5rm9(l)l s 1  1 SPMTA 7:C 5[ 00A ade k d[
   00ano:ameoi .Q1B[ 00ac _idaM00080oo'"

If the bootloader was using the DMA ("DM") mode, output would likely fail
entirely. Later, when the full serial driver probes, the port is
re-initialized and output works as expected.

Fix this also for earlycon by clearing the DMEN register and
reset+re-enable the transmitter to apply the change. This ensures the
transmitter is in the expected state before writing any output.

Cc: stable <stable@kernel.org>
Fixes: 0efe72963409 ("tty: serial: msm: Add earlycon support")
Signed-off-by: Stephan Gerhold <stephan.gerhold@linaro.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20250408-msm-serial-earlycon-v1-1-429080127530@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: serial: fsl_lpuart: disable transmitter before changing RS485 related registers 2025-04-10T12:33:41+00:00 Sherry Sun sherry.sun@nxp.com 2025-03-12T02:25:03+00:00 bbadf5038386ce217f6da5e9cdda47cbe902e7bd [ Upstream commit f5cb528d6441eb860250a2f085773aac4f44085e ] According to the LPUART reference manual, TXRTSE and TXRTSPOL of MODIR register only can be changed when the transmitter is disabled. So disable the transmitter before changing RS485 related registers and re-enable it after the change is done. Fixes: 67b01837861c ("tty: serial: lpuart: Add RS485 support for 32-bit uart flavour") Cc: stable <stable@kernel.org> Signed-off-by: Sherry Sun <sherry.sun@nxp.com> Reviewed-by: Frank Li <Frank.Li@nxp.com> Link: https://lore.kernel.org/r/20250312022503.1342990-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit f5cb528d6441eb860250a2f085773aac4f44085e ]

According to the LPUART reference manual, TXRTSE and TXRTSPOL of MODIR
register only can be changed when the transmitter is disabled.
So disable the transmitter before changing RS485 related registers and
re-enable it after the change is done.

Fixes: 67b01837861c ("tty: serial: lpuart: Add RS485 support for 32-bit uart flavour")
Cc: stable <stable@kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250312022503.1342990-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
tty: serial: fsl_lpuart: use UARTMODIR register bits for lpuart32 platform 2025-04-10T12:33:41+00:00 Sherry Sun sherry.sun@nxp.com 2023-04-14T02:21:11+00:00 a824c44e4ba5fdadd997c35e4076e3e5b6005e9a [ Upstream commit d57d56e4dddfb5c92cd81abf8922055bf0fb85a4 ] For lpuart32 platforms, UARTMODIR register is used instead of UARTMODEM. So here should configure the corresponding UARTMODIR register bits to avoid confusion. Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Sherry Sun <sherry.sun@nxp.com> Link: https://lore.kernel.org/r/20230414022111.20896-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: f5cb528d6441 ("tty: serial: fsl_lpuart: disable transmitter before changing RS485 related registers") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit d57d56e4dddfb5c92cd81abf8922055bf0fb85a4 ]

For lpuart32 platforms, UARTMODIR register is used instead of UARTMODEM.
So here should configure the corresponding UARTMODIR register bits to
avoid confusion.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230414022111.20896-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: f5cb528d6441 ("tty: serial: fsl_lpuart: disable transmitter before changing RS485 related registers")
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: 8250_dma: terminate correct DMA in tx_dma_flush() 2025-04-07T08:05:46+00:00 John Keeping jkeeping@inmusicbrands.com 2025-02-24T12:18:30+00:00 1a8d68ca7752c5af1b7d526cd4a61301ca404114 commit a26503092c75abba70a0be2aa01145ecf90c2a22 upstream. When flushing transmit side DMA, it is the transmit channel that should be terminated, not the receive channel. Fixes: 9e512eaaf8f40 ("serial: 8250: Fix fifo underflow on flush") Cc: stable <stable@kernel.org> Reported-by: Wentao Guan <guanwentao@uniontech.com> Signed-off-by: John Keeping <jkeeping@inmusicbrands.com> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20250224121831.1429323-1-jkeeping@inmusicbrands.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a26503092c75abba70a0be2aa01145ecf90c2a22 upstream.

When flushing transmit side DMA, it is the transmit channel that should
be terminated, not the receive channel.

Fixes: 9e512eaaf8f40 ("serial: 8250: Fix fifo underflow on flush")
Cc: stable <stable@kernel.org>
Reported-by: Wentao Guan <guanwentao@uniontech.com>
Signed-off-by: John Keeping <jkeeping@inmusicbrands.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20250224121831.1429323-1-jkeeping@inmusicbrands.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: serial: 8250: Add Brainboxes XC devices 2025-04-07T08:05:45+00:00 Cameron Williams cang1@live.co.uk 2025-03-10T22:27:10+00:00 eb7cfa77f57ee6255163176a5b921fe2ed38c20f commit 5c7e2896481a177bbda41d7850f05a9f5a8aee2b upstream. These ExpressCard devices use the OxPCIE chip and can be used with this driver. Signed-off-by: Cameron Williams <cang1@live.co.uk> Cc: stable <stable@kernel.org> Link: https://lore.kernel.org/r/DB7PR02MB3802907A9360F27F6CD67AAFC4D62@DB7PR02MB3802.eurprd02.prod.outlook.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 5c7e2896481a177bbda41d7850f05a9f5a8aee2b upstream.

These ExpressCard devices use the OxPCIE chip and can be used with
this driver.

Signed-off-by: Cameron Williams <cang1@live.co.uk>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/DB7PR02MB3802907A9360F27F6CD67AAFC4D62@DB7PR02MB3802.eurprd02.prod.outlook.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: serial: 8250: Add some more device IDs 2025-04-07T08:05:45+00:00 Cameron Williams cang1@live.co.uk 2025-02-23T22:07:38+00:00 ded9ea3814d0b768f5594c99da080fb9f1380a4e commit be6a23650908e2f827f2e7839a3fbae41ccb5b63 upstream. These card IDs got missed the first time around. Cc: stable <stable@kernel.org> Signed-off-by: Cameron Williams <cang1@live.co.uk> Link: https://lore.kernel.org/r/DB7PR02MB380295BCC879CCF91315AC38C4C12@DB7PR02MB3802.eurprd02.prod.outlook.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit be6a23650908e2f827f2e7839a3fbae41ccb5b63 upstream.

These card IDs got missed the first time around.

Cc: stable <stable@kernel.org>
Signed-off-by: Cameron Williams <cang1@live.co.uk>
Link: https://lore.kernel.org/r/DB7PR02MB380295BCC879CCF91315AC38C4C12@DB7PR02MB3802.eurprd02.prod.outlook.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: 8250_pci: add support for ASIX AX99100 2025-02-21T12:50:11+00:00 Jiaqing Zhao jiaqing.zhao@linux.intel.com 2023-07-24T08:39:32+00:00 06c3423c62b39d4277b6b5eb332b1bba0d6bc032 commit 0b32216557ce3b2a468d1282d99b428bf72ff532 upstream. Each of the 4 PCI functions on ASIX AX99100 PCIe to Multi I/O Controller can be configured as a single-port serial port controller. The subvendor id is 0x1000 when configured as serial port and MSI interrupts are supported. Signed-off-by: Jiaqing Zhao <jiaqing.zhao@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20230724083933.3173513-4-jiaqing.zhao@linux.intel.com Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 0b32216557ce3b2a468d1282d99b428bf72ff532 upstream.

Each of the 4 PCI functions on ASIX AX99100 PCIe to Multi I/O
Controller can be configured as a single-port serial port controller.
The subvendor id is 0x1000 when configured as serial port and MSI
interrupts are supported.

Signed-off-by: Jiaqing Zhao <jiaqing.zhao@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230724083933.3173513-4-jiaqing.zhao@linux.intel.com
Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: 8250: Fix fifo underflow on flush 2025-02-21T12:50:04+00:00 John Keeping jkeeping@inmusicbrands.com 2025-02-08T12:41:44+00:00 d470522c597b73e63cca04f3012aec28185113b7 commit 9e512eaaf8f4008c44ede3dfc0fbc9d9c5118583 upstream. When flushing the serial port's buffer, uart_flush_buffer() calls kfifo_reset() but if there is an outstanding DMA transfer then the completion function will consume data from the kfifo via uart_xmit_advance(), underflowing and leading to ongoing DMA as the driver tries to transmit another 2^32 bytes. This is readily reproduced with serial-generic and amidi sending even short messages as closing the device on exit will wait for the fifo to drain and in the underflow case amidi hangs for 30 seconds on exit in tty_wait_until_sent(). A trace of that gives: kworker/1:1-84 [001] 51.769423: bprint: serial8250_tx_dma: tx_size=3 fifo_len=3 amidi-763 [001] 51.769460: bprint: uart_flush_buffer: resetting fifo irq/21-fe530000-76 [000] 51.769474: bprint: __dma_tx_complete: tx_size=3 irq/21-fe530000-76 [000] 51.769479: bprint: serial8250_tx_dma: tx_size=4096 fifo_len=4294967293 irq/21-fe530000-76 [000] 51.781295: bprint: __dma_tx_complete: tx_size=4096 irq/21-fe530000-76 [000] 51.781301: bprint: serial8250_tx_dma: tx_size=4096 fifo_len=4294963197 irq/21-fe530000-76 [000] 51.793131: bprint: __dma_tx_complete: tx_size=4096 irq/21-fe530000-76 [000] 51.793135: bprint: serial8250_tx_dma: tx_size=4096 fifo_len=4294959101 irq/21-fe530000-76 [000] 51.804949: bprint: __dma_tx_complete: tx_size=4096 Since the port lock is held in when the kfifo is reset in uart_flush_buffer() and in __dma_tx_complete(), adding a flush_buffer hook to adjust the outstanding DMA byte count is sufficient to avoid the kfifo underflow. Fixes: 9ee4b83e51f74 ("serial: 8250: Add support for dmaengine") Cc: stable <stable@kernel.org> Signed-off-by: John Keeping <jkeeping@inmusicbrands.com> Link: https://lore.kernel.org/r/20250208124148.1189191-1-jkeeping@inmusicbrands.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9e512eaaf8f4008c44ede3dfc0fbc9d9c5118583 upstream.

When flushing the serial port's buffer, uart_flush_buffer() calls
kfifo_reset() but if there is an outstanding DMA transfer then the
completion function will consume data from the kfifo via
uart_xmit_advance(), underflowing and leading to ongoing DMA as the
driver tries to transmit another 2^32 bytes.

This is readily reproduced with serial-generic and amidi sending even
short messages as closing the device on exit will wait for the fifo to
drain and in the underflow case amidi hangs for 30 seconds on exit in
tty_wait_until_sent().  A trace of that gives:

     kworker/1:1-84    [001]    51.769423: bprint:               serial8250_tx_dma: tx_size=3 fifo_len=3
           amidi-763   [001]    51.769460: bprint:               uart_flush_buffer: resetting fifo
 irq/21-fe530000-76    [000]    51.769474: bprint:               __dma_tx_complete: tx_size=3
 irq/21-fe530000-76    [000]    51.769479: bprint:               serial8250_tx_dma: tx_size=4096 fifo_len=4294967293
 irq/21-fe530000-76    [000]    51.781295: bprint:               __dma_tx_complete: tx_size=4096
 irq/21-fe530000-76    [000]    51.781301: bprint:               serial8250_tx_dma: tx_size=4096 fifo_len=4294963197
 irq/21-fe530000-76    [000]    51.793131: bprint:               __dma_tx_complete: tx_size=4096
 irq/21-fe530000-76    [000]    51.793135: bprint:               serial8250_tx_dma: tx_size=4096 fifo_len=4294959101
 irq/21-fe530000-76    [000]    51.804949: bprint:               __dma_tx_complete: tx_size=4096

Since the port lock is held in when the kfifo is reset in
uart_flush_buffer() and in __dma_tx_complete(), adding a flush_buffer
hook to adjust the outstanding DMA byte count is sufficient to avoid the
kfifo underflow.

Fixes: 9ee4b83e51f74 ("serial: 8250: Add support for dmaengine")
Cc: stable <stable@kernel.org>
Signed-off-by: John Keeping <jkeeping@inmusicbrands.com>
Link: https://lore.kernel.org/r/20250208124148.1189191-1-jkeeping@inmusicbrands.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: xilinx_uartps: split sysrq handling 2025-02-21T12:49:54+00:00 Sean Anderson sean.anderson@linux.dev 2025-01-10T21:38:22+00:00 de5bd24197bd9ee37ec1e379a3d882bbd15c5065 commit b06f388994500297bb91be60ffaf6825ecfd2afe upstream. lockdep detects the following circular locking dependency: CPU 0 CPU 1 ========================== ============================ cdns_uart_isr() printk() uart_port_lock(port) console_lock() cdns_uart_console_write() if (!port->sysrq) uart_port_lock(port) uart_handle_break() port->sysrq = ... uart_handle_sysrq_char() printk() console_lock() The fixed commit attempts to avoid this situation by only taking the port lock in cdns_uart_console_write if port->sysrq unset. However, if (as shown above) cdns_uart_console_write runs before port->sysrq is set, then it will try to take the port lock anyway. This may result in a deadlock. Fix this by splitting sysrq handling into two parts. We use the prepare helper under the port lock and defer handling until we release the lock. Fixes: 74ea66d4ca06 ("tty: xuartps: Improve sysrq handling") Signed-off-by: Sean Anderson <sean.anderson@linux.dev> Cc: stable@vger.kernel.org # c980248179d: serial: xilinx_uartps: Use port lock wrappers Acked-by: John Ogness <john.ogness@linutronix.de> Link: https://lore.kernel.org/r/20250110213822.2107462-1-sean.anderson@linux.dev Signed-off-by: Sean Anderson <sean.anderson@linux.dev> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit b06f388994500297bb91be60ffaf6825ecfd2afe upstream.

lockdep detects the following circular locking dependency:

CPU 0                      CPU 1
========================== ============================
cdns_uart_isr()            printk()
  uart_port_lock(port)       console_lock()
			     cdns_uart_console_write()
                               if (!port->sysrq)
                                 uart_port_lock(port)
  uart_handle_break()
    port->sysrq = ...
  uart_handle_sysrq_char()
    printk()
      console_lock()

The fixed commit attempts to avoid this situation by only taking the
port lock in cdns_uart_console_write if port->sysrq unset. However, if
(as shown above) cdns_uart_console_write runs before port->sysrq is set,
then it will try to take the port lock anyway. This may result in a
deadlock.

Fix this by splitting sysrq handling into two parts. We use the prepare
helper under the port lock and defer handling until we release the lock.

Fixes: 74ea66d4ca06 ("tty: xuartps: Improve sysrq handling")
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Cc: stable@vger.kernel.org # c980248179d: serial: xilinx_uartps: Use port lock wrappers
Acked-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/r/20250110213822.2107462-1-sean.anderson@linux.dev
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>