linux-stable.git/drivers/tty, branch v4.14.9

serdev: ttyport: enforce tty-driver open() requirement

2017-12-20T09:10:33+00:00

[ Upstream commit dee7d0f3b200c67c6ee96bd37c6e8fa52690ab56 ]

The tty-driver open routine is mandatory, but the serdev
tty-port-controller implementation did not treat it as such and would
instead fall back to calling tty_port_open() directly.

Signed-off-by: Johan Hovold 
Acked-by: Rob Herring 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

serdev: ttyport: fix tty locking in close

2017-12-14T08:52:44+00:00

commit 90dbad8cd6efccbdce109d5ef0724f8434a6cdde upstream.

Make sure to hold the tty lock as required when calling tty-driver
close() (e.g. to avoid racing with hangup()).

Note that the serport active flag is currently set under the lock at
controller open, but really isn't protected by it.

Fixes: cd6484e1830b ("serdev: Introduce new bus for serial attached devices")
Signed-off-by: Johan Hovold 
Signed-off-by: Greg Kroah-Hartman

serdev: ttyport: fix NULL-deref on hangup

2017-12-14T08:52:44+00:00

commit 8bcd4e6a8decac251d55c4377e2e67f052777ce0 upstream.

Make sure to use a properly refcounted tty_struct in write_wake up to
avoid dereferencing a NULL-pointer when a port is being hung up.

Fixes: bed35c6dfa6a ("serdev: add a tty port controller driver")
Signed-off-by: Johan Hovold 
Signed-off-by: Greg Kroah-Hartman

serdev: ttyport: add missing receive_buf sanity checks

2017-12-14T08:52:44+00:00

commit eb281683621b71ab9710d9dccbbef0c2e1769c97 upstream.

The receive_buf tty-port callback should return the number of bytes
accepted and must specifically never return a negative errno (or a value
larger than the buffer size) to the tty layer.

A serdev driver not providing a receive_buf callback would currently
cause the flush_to_ldisc() worker to spin in a tight loop when the tty
buffer pointers are incremented with -EINVAL (-22) after data has been
received.

A serdev driver occasionally returning a negative errno (or a too large
byte count) could cause information leaks or crashes when accessing
memory outside the tty buffers in consecutive callbacks.

Fixes: cd6484e1830b ("serdev: Introduce new bus for serial attached devices")
Signed-off-by: Johan Hovold 
Signed-off-by: Greg Kroah-Hartman

serial: imx: Update cached mctrl value when changing RTS

2017-12-10T12:40:42+00:00

[ Upstream commit a0983c742a5885f82afb282166f83f1d3d8addf4 ]

UART core function uart_update_mctrl relies on a cached value of
modem control lines. This was used but not updated by local RTS
control functions within imx.c. These are used for RS485 line
driver enable signalling. Having an out-of-date value in the cached
mctrl can result in the transmitter being enabled when it shouldn't
be.

Fix this by updating the mctrl value before applying it.

Signed-off-by: Ian Jamison 
Origin: id:8195c96e674517b82a6ff7fe914c7ba0f86e702b.1505375165.git.ian.dev@arkver.com
Acked-by: Uwe Kleine-König 
Tested-by: Uwe Kleine-König 
Tested-by: Clemens Gruber 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: suppress warning for ports without dma channels

2017-12-10T12:40:42+00:00

[ Upstream commit 7464779fa8551b90d5797d4020b0bdb7e6422eb9 ]

If a port has no dma channel defined in the device tree, then
don't attempt to allocate a dma channel for the port.
Also suppress the warning message concerning the failure to allocate
a dma channel.  Continue to emit the warning message if a dma
channel is defined but cannot be allocated.

Signed-off-by: Andy Lowe 
Signed-off-by: Eugeniu Rosca 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

sysrq : fix Show Regs call trace on ARM

2017-12-10T12:40:42+00:00

[ Upstream commit b00bebbc301c8e1f74f230dc82282e56b7e7a6db ]

When kernel configuration SMP,PREEMPT and DEBUG_PREEMPT are enabled,
echo 1 >/proc/sys/kernel/sysrq
echo p >/proc/sysrq-trigger
kernel will print call trace as below:

sysrq: SysRq : Show Regs
BUG: using __this_cpu_read() in preemptible [00000000] code: sh/435
caller is __this_cpu_preempt_check+0x18/0x20
Call trace:
[] dump_backtrace+0x0/0x1d0
[] show_stack+0x24/0x30
[] dump_stack+0x90/0xb0
[] check_preemption_disabled+0x100/0x108
[] __this_cpu_preempt_check+0x18/0x20
[] sysrq_handle_showregs+0x1c/0x40
[] __handle_sysrq+0x12c/0x1a0
[] write_sysrq_trigger+0x60/0x70
[] proc_reg_write+0x90/0xd0
[] __vfs_write+0x48/0x90
[] vfs_write+0xa4/0x190
[] SyS_write+0x54/0xb0
[] el0_svc_naked+0x24/0x28

This can be seen on a common board like an r-pi3.
This happens because when echo p >/proc/sysrq-trigger,
get_irq_regs() is called outside of IRQ context,
if preemption is enabled in this situation,kernel will
print the call trace. Since many prior discussions on
the mailing lists have made it clear that get_irq_regs
either just returns NULL or stale data when used outside
of IRQ context,we simply avoid calling it outside of
IRQ context.

Signed-off-by: Jibin Xu 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

serial: 8250: Preserve DLD[7:4] for PORT_XR17V35X

2017-12-10T12:40:40+00:00

[ Upstream commit 0ab84da2e076948c49d36197ee7d254125c53eab ]

The upper four bits of the XR17V35x fractional divisor register (DLD)
control general chip function (RS-485 direction pin polarity, multidrop
mode, XON/XOFF parity check, and fast IR mode). Don't allow these bits
to be clobbered when setting the baudrate.

Signed-off-by: Aaron Sierra 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_fintek: Fix rs485 disablement on invalid ioctl()

2017-12-10T12:40:39+00:00

[ Upstream commit 3236a965486ba0c6043cf2c7b51943d8b382ae29 ]

This driver's ->rs485_config callback checks if SER_RS485_RTS_ON_SEND
and SER_RS485_RTS_AFTER_SEND have the same value.  If they do, it means
the user has passed in invalid data with the TIOCSRS485 ioctl()
since RTS must have a different polarity when sending and when not
sending.  In this case, rs485 mode is not enabled (the RS485_URA bit
is not set in the RS485 Enable Register) and this is supposed to be
signaled back to the user by clearing the SER_RS485_ENABLED bit in
struct serial_rs485 ... except a missing tilde character is preventing
that from happening.

Fixes: 28e3fb6c4dce ("serial: Add support for Fintek F81216A LPC to 4 UART")
Cc: Ricardo Ribalda Delgado 
Cc: "Ji-Ze Hong (Peter Hong)" 
Signed-off-by: Lukas Wunner 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_early: Only set divisor if valid clk & baud

2017-12-10T12:40:38+00:00

commit 0ff3ab701963a845d52337ded7eebf2d1a14fe00 upstream.

If either uartclk or baud are 0, avoid calculating and setting a divisor
based on them since the output will almost certainly be garbage.

This also allows platforms such as the MIPS generic kernel, which has no
way to know a valid BASE_BASE for the board it is actually booted on at
compile time, to set BASE_BAUD to 0 and avoid early_8250 setting a bad
divisor.

This fixes a regression caused by commit 31cb9a8575ca ("earlycon:
initialise baud field of earlycon device structure"), which changed the
behavior of of_setup_earlycon such that it sets a baud rate in the
earlycon structure where previously it was left as 0. All boards
supported by the MIPS generic kernel started outputting garbage from the
boot console due to an incorrect divisor being set.

Fixes: 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure")
Signed-off-by: Matt Redfearn 
Signed-off-by: Greg Kroah-Hartman