linux-stable.git/drivers/tty, branch v5.9.3

serial: pl011: Fix lockdep splat when handling magic-sysrq interrupt

2020-11-01T11:47:09+00:00

commit 534cf755d9df99e214ddbe26b91cd4d81d2603e2 upstream.

Issuing a magic-sysrq via the PL011 causes the following lockdep splat,
which is easily reproducible under QEMU:

  | sysrq: Changing Loglevel
  | sysrq: Loglevel set to 9
  |
  | ======================================================
  | WARNING: possible circular locking dependency detected
  | 5.9.0-rc7 #1 Not tainted
  | ------------------------------------------------------
  | systemd-journal/138 is trying to acquire lock:
  | ffffab133ad950c0 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable+0x34/0x70
  |
  | but task is already holding lock:
  | ffff0001fd47b098 (&port_lock_key){-.-.}-{2:2}, at: pl011_int+0x40/0x488
  |
  | which lock already depends on the new lock.

  [...]

  |  Possible unsafe locking scenario:
  |
  |        CPU0                    CPU1
  |        ----                    ----
  |   lock(&port_lock_key);
  |                                lock(console_owner);
  |                                lock(&port_lock_key);
  |   lock(console_owner);
  |
  |  *** DEADLOCK ***

The issue being that CPU0 takes 'port_lock' on the irq path in pl011_int()
before taking 'console_owner' on the printk() path, whereas CPU1 takes
the two locks in the opposite order on the printk() path due to setting
the "console_owner" prior to calling into into the actual console driver.

Fix this in the same way as the msm-serial driver by dropping 'port_lock'
before handling the sysrq.

Cc:  # 4.19+
Cc: Russell King 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Link: https://lore.kernel.org/r/20200811101313.GA6970@willie-the-truck
Signed-off-by: Peter Zijlstra 
Tested-by: Will Deacon 
Signed-off-by: Will Deacon 
Link: https://lore.kernel.org/r/20200930120432.16551-1-will@kernel.org
Signed-off-by: Greg Kroah-Hartman

serial: qcom_geni_serial: To correct QUP Version detection logic

2020-11-01T11:47:09+00:00

commit c9ca43d42ed8d5fd635d327a664ed1d8579eb2af upstream.

For QUP IP versions 2.5 and above the oversampling rate is
halved from 32 to 16.

Commit ce734600545f ("tty: serial: qcom_geni_serial: Update
the oversampling rate") is pushed to handle this scenario.
But the existing logic is failing to classify QUP Version 3.0
into the correct group ( 2.5 and above).

As result Serial Engine clocks are not configured properly for
baud rate and garbage data is sampled to FIFOs from the line.

So, fix the logic to detect QUP with versions 2.5 and above.

Fixes: ce734600545f ("tty: serial: qcom_geni_serial: Update the oversampling rate")
Cc: stable 
Signed-off-by: Paras Sharma 
Reviewed-by: Akash Asthana 
Link: https://lore.kernel.org/r/1601445926-23673-1-git-send-email-parashar@codeaurora.org
Signed-off-by: Greg Kroah-Hartman

tty: serial: fsl_lpuart: fix lpuart32_poll_get_char

2020-10-29T09:12:21+00:00

commit 29788ab1d2bf26c130de8f44f9553ee78a27e8d5 upstream.

The watermark is set to 1, so we need to input two chars to trigger RDRF
using the original logic. With the new logic, we could always get the
char when there is data in FIFO.

Suggested-by: Fugang Duan 
Signed-off-by: Peng Fan 
Link: https://lore.kernel.org/r/20200929095509.21680-1-peng.fan@nxp.com
Cc: stable 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

tty: serial: lpuart: fix lpuart32_write usage

2020-10-29T09:12:21+00:00

commit 9ea40db477c024dcb87321b7f32bd6ea12130ac2 upstream.

The 2nd and 3rd parameter were wrongly used, and cause kernel abort when
doing kgdb debug.

Fixes: 1da17d7cf8e2 ("tty: serial: fsl_lpuart: Use appropriate lpuart32_* I/O funcs")
Cc: stable 
Signed-off-by: Peng Fan 
Link: https://lore.kernel.org/r/20200929091920.22612-1-peng.fan@nxp.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

tty: ipwireless: fix error handling

2020-10-29T09:12:18+00:00

[ Upstream commit db332356222d9429731ab9395c89cca403828460 ]

ipwireless_send_packet() can only return 0 on success and -ENOMEM on
error, the caller should check non zero for error condition

Signed-off-by: Tong Zhang 
Acked-by: David Sterba 
Link: https://lore.kernel.org/r/20200821161942.36589-1-ztong0001@gmail.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250_dw: Fix clk-notifier/port suspend deadlock

2020-10-29T09:11:32+00:00

[ Upstream commit 85985a3dcd7415dd849cf62ec14f931cd905099a ]

It has been discovered that there is a potential deadlock between
the clock-change-notifier thread and the UART port suspending one:

   CPU0 (suspend CPU/UART)   CPU1 (update clock)
            ----                    ----
   lock(&port->mutex);
                             lock((work_completion)(&data->clk_work));
                             lock(&port->mutex);
   lock((work_completion)(&data->clk_work));

   *** DEADLOCK ***

The best way to fix this is to eliminate the CPU0
port->mutex/work-completion scenario. So we suggest to register and
unregister the clock-notifier during the DW APB UART port probe/remove
procedures, instead of doing that at the points of the port
startup/shutdown.

Link: https://lore.kernel.org/linux-serial/f1cd5c75-9cda-6896-a4e2-42c5bfc3f5c3@redhat.com

Fixes: cc816969d7b5 ("serial: 8250_dw: Fix common clocks usage race condition")
Reported-by: Hans de Goede 
Tested-by: Hans de Goede 
Signed-off-by: Serge Semin 
Link: https://lore.kernel.org/r/20200923161950.6237-4-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250: Skip uninitialized TTY port baud rate update

2020-10-29T09:11:31+00:00

[ Upstream commit c8dff3aa824177013d90967687f09f713a55d13f ]

It is erroneous to update the TTY port baud rate if it hasn't been
initialized yet, because in that case the TTY struct isn't set. So there
is no termios structure to get and re-calculate the baud if the current
baud can't be reached. Let's skip the baud rate update then until the port
is fully initialized.

Note the update UART clock method still sets the uartclk member with a new
ref clock value even if the port is turned off. The new UART ref clock
rate will be used later on the port starting up procedure.

Fixes: 868f3ee6e452 ("serial: 8250: Add 8250 port clock update method")
Tested-by: Hans de Goede 
Signed-off-by: Serge Semin 
Link: https://lore.kernel.org/r/20200923161950.6237-3-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250: Discard RTS/DTS setting from clock update method

2020-10-29T09:11:31+00:00

[ Upstream commit 7718453e36960dadb8dc46f2b514b309659e1270 ]

It has been a mistake to add the MCR register RTS/DTS fields setting in
the generic method of the UART reference clock update. There is no point
in asserting these lines at that procedure. Just discard the
serial8250_out_MCR() mathod invocation from there then.

Fixes: 868f3ee6e452 ("serial: 8250: Add 8250 port clock update method")
Tested-by: Hans de Goede 
Signed-off-by: Serge Semin 
Link: https://lore.kernel.org/r/20200923161950.6237-2-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: serial: imx: fix link error with CONFIG_SERIAL_CORE_CONSOLE=n

2020-10-29T09:11:29+00:00

[ Upstream commit 24c796926e2f88b383a76ddc871a7cdd62484f3a ]

aarch64-linux-gnu-ld: drivers/tty/serial/imx_earlycon.o: in function `imx_uart_console_early_write':
imx_earlycon.c:(.text+0x84): undefined reference to `uart_console_write'

The driver uses the uart_console_write(), but SERIAL_CORE_CONSOLE is not
selected, so uart_console_write is not defined, then we get the error.
Fix this by selecting SERIAL_CORE_CONSOLE.

Fixes: 699cc4dfd140 ("tty: serial: imx: add imx earlycon driver")
Reported-by: Hulk Robot 
Signed-off-by: Yang Yingliang 
Link: https://lore.kernel.org/r/20200919063240.2754965-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: hvc: fix link error with CONFIG_SERIAL_CORE_CONSOLE=n

2020-10-29T09:11:29+00:00

[ Upstream commit 75fc65079d8253e1c25a5f8348111a85d71e0f01 ]

aarch64-linux-gnu-ld: drivers/tty/hvc/hvc_dcc.o: in function `dcc_early_write':
hvc_dcc.c:(.text+0x164): undefined reference to `uart_console_write'

The driver uses the uart_console_write(), but SERIAL_CORE_CONSOLE is not
selected, so uart_console_write is not defined, then we get the error.
Fix this by selecting SERIAL_CORE_CONSOLE.

Fixes: d1a1af2cdf19 ("hvc: dcc: Add earlycon support")
Reported-by: Hulk Robot 
Signed-off-by: Yang Yingliang 
Link: https://lore.kernel.org/r/20200919063535.2809707-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin