linux-stable.git/drivers/tty, branch linux-4.8.y

sc16is7xx: Drop bogus use of IRQF_ONESHOT

2017-01-09T07:21:56+00:00

commit 04da73803c05dc1150ccc31cbf93e8cd56679c09 upstream.

The use of IRQF_ONESHOT when registering an interrupt handler with
request_irq() is non-sensical.

Not only that, it also prevents the handler from being threaded when it
otherwise should be w/ IRQ_FORCED_THREADING is enabled.  This causes the
following deadlock observed by Sean Nyekjaer on -rt:

Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
[..]
   rt_spin_lock_slowlock from queue_kthread_work
   queue_kthread_work from sc16is7xx_irq
   sc16is7xx_irq [sc16is7xx] from handle_irq_event_percpu
   handle_irq_event_percpu from handle_irq_event
   handle_irq_event from handle_level_irq
   handle_level_irq from generic_handle_irq
   generic_handle_irq from mxc_gpio_irq_handler
   mxc_gpio_irq_handler from mx3_gpio_irq_handler
   mx3_gpio_irq_handler from generic_handle_irq
   generic_handle_irq from __handle_domain_irq
   __handle_domain_irq from gic_handle_irq
   gic_handle_irq from __irq_svc
   __irq_svc from rt_spin_unlock
   rt_spin_unlock from kthread_worker_fn
   kthread_worker_fn from kthread
   kthread from ret_from_fork

Fixes: 9e6f4ca3e567 ("sc16is7xx: use kthread_worker for tx_work and irq")
Reported-by: Sean Nyekjaer 
Signed-off-by: Josh Cartwright 
Cc: linux-rt-users@vger.kernel.org
Cc: Jakub Kicinski 
Cc: linux-serial@vger.kernel.org
Cc: Sebastian Andrzej Siewior 
Signed-off-by: Julia Cartwright 
Acked-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

vt: fix Scroll Lock LED trigger name

2017-01-09T07:21:53+00:00

commit 31b5929d533f5183972cf57a7844b456ed996f3c upstream.

There is a disagreement between drivers/tty/vt/keyboard.c and
drivers/input/input-leds.c with regard to what is a Scroll Lock LED
trigger name: input calls it "kbd-scrolllock", but vt calls it
"kbd-scrollock" (two l's).
This prevents Scroll Lock LED trigger from binding to this LED by default.

Since it is a scroLL Lock LED, this interface was introduced only about a
year ago and in an Internet search people seem to reference this trigger
only to set it to this LED let's simply rename it to "kbd-scrolllock".

Also, it looks like this was supposed to be changed before this code was
merged: https://lkml.org/lkml/2015/6/9/697 but it was done only on
the input side.

Signed-off-by: Maciej S. Szmigiero 
Acked-by: Samuel Thibault 
Signed-off-by: Greg Kroah-Hartman

tty/serial: at91: fix hardware handshake on Atmel platforms

2016-11-18T09:51:49+00:00

commit 9bcffe7575b721d7b6d9b3090fe18809d9806e78 upstream.

After commit 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management
when hardware handshake is enabled"), the hardware handshake wasn't
functional anymore on Atmel platforms (beside SAMA5D2).

To understand why, one has to understand the flag ATMEL_US_USMODE_HWHS
first:
Before commit 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management
when hardware handshake is enabled"), this flag was never set.
Thus, the CTS/RTS where only handled by serial_core (and everything
worked just fine).

This commit introduced the use of the ATMEL_US_USMODE_HWHS flag,
enabling it for all boards when the user space enables flow control.

When the ATMEL_US_USMODE_HWHS is set, the Atmel USART controller
handles a part of the flow control job:
- disable the transmitter when the CTS pin gets high.
- drive the RTS pin high when the DMA buffer transfer is completed or
  PDC RX buffer full or RX FIFO is beyond threshold. (depending on the
  controller version).

NB: This feature is *not* mandatory for the flow control to work.
(Nevertheless, it's very useful if low latencies are needed.)

Now, the specifics of the ATMEL_US_USMODE_HWHS flag:

- For platforms with DMAC and no FIFOs (sam9x25, sam9x35, sama5D3,
sama5D4, sam9g15, sam9g25, sam9g35)* this feature simply doesn't work.
( source: https://lkml.org/lkml/2016/9/7/598 )
Tested it on sam9g35, the RTS pins always stays up, even when RXEN=1
or a new DMA transfer descriptor is set.
=> ATMEL_US_USMODE_HWHS must not be used for those platforms

- For platforms with a PDC (sam926{0,1,3}, sam9g10, sam9g20, sam9g45,
sam9g46)*, there's another kind of problem. Once the flag
ATMEL_US_USMODE_HWHS is set, the RTS pin can't be driven anymore via
RTSEN/RTSDIS in USART Control Register. The RTS pin can only be driven
by enabling/disabling the receiver or setting RCR=RNCR=0 in the PDC
(Receive (Next) Counter Register).
=> Doing this is beyond the scope of this patch and could add other
bugs, so the original (and working) behaviour should be set for those
platforms (meaning ATMEL_US_USMODE_HWHS flag should be unset).

- For platforms with a FIFO (sama5d2)*, the RTS pin is driven according
to the RX FIFO thresholds, and can be also driven by RTSEN/RTSDIS in
USART Control Register. No problem here.
(This was the use case of commit 1cf6e8fc8341 ("tty/serial: at91: fix
RTS line management when hardware handshake is enabled"))
NB: If the CTS pin declared as a GPIO in the DTS, (for instance
cts-gpios = <&pioA PIN_PB31 GPIO_ACTIVE_LOW>), the transmitter will be
disabled.
=> ATMEL_US_USMODE_HWHS flag can be set for this platform ONLY IF the
CTS pin is not a GPIO.

So, the only case when ATMEL_US_USMODE_HWHS can be enabled is when
(atmel_use_fifo(port) &&
 !mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS))

Tested on all Atmel USART controller flavours:
AT91SAM9G35-CM (DMAC flavour), AT91SAM9G20-EK (PDC flavour),
SAMA5D2xplained (FIFO flavour).

* the list may not be exhaustive

Fixes: 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management when hardware handshake is enabled")
Signed-off-by: Richard Genoud 
Acked-by: Alexandre Belloni 
Acked-by: Cyrille Pitchen 
Acked-by: Uwe Kleine-König 
[nicolas.ferre@atmel.com: adapt to 4.4.x kernel for stable by adding
the atmel_port variable declaration which was missing]
Signed-off-by: Nicolas Ferre 
Signed-off-by: Greg Kroah-Hartman

tty: vt, fix bogus division in csi_J

2016-11-10T15:38:57+00:00

commit 42acfc6615f47e465731c263bee0c799edb098f2 upstream.

In csi_J(3), the third parameter of scr_memsetw (vc_screenbuf_size) is
divided by 2 inappropriatelly. But scr_memsetw expects size, not
count, because it divides the size by 2 on its own before doing actual
memset-by-words.

So remove the bogus division.

Signed-off-by: Jiri Slaby 
Cc: Petr Písař 
Fixes: f8df13e0a9 (tty: Clean console safely)
Signed-off-by: Greg Kroah-Hartman

tty: limit terminal size to 4M chars

2016-11-10T15:38:50+00:00

commit 32b2921e6a7461fe63b71217067a6cf4bddb132f upstream.

Size of kmalloc() in vc_do_resize() is controlled by user.
Too large kmalloc() size triggers WARNING message on console.
Put a reasonable upper bound on terminal size to prevent WARNINGs.

Signed-off-by: Dmitry Vyukov 
CC: David Rientjes 
Cc: One Thousand Gnomes 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Cc: Peter Hurley 
Cc: linux-kernel@vger.kernel.org
Cc: syzkaller@googlegroups.com
Signed-off-by: Greg Kroah-Hartman

vt: clear selection before resizing

2016-11-10T15:38:50+00:00

commit 009e39ae44f4191188aeb6dfbf661b771dbbe515 upstream.

When resizing a vt its selection may exceed the new size, resulting in
an invalid memory access [1]. Clear the selection before resizing.

[1] http://lkml.kernel.org/r/CACT4Y+acDTwy4umEvf5ROBGiRJNrxHN4Cn5szCXE5Jw-d1B=Xw@mail.gmail.com

Reported-and-tested-by: Dmitry Vyukov 
Signed-off-by: Scot Doyle 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_port: fix runtime PM use in __do_stop_tx_rs485()

2016-10-22T10:40:21+00:00

commit b3965767d86cf4534dfe1affbde0453d3224ed7f upstream.

There are calls to serial8250_rpm_{get|put}() in __do_stop_tx_rs485() that are
certainly placed in a wrong location. I dunno how it had been tested with
runtime PM enabled because it is obvious "sleep in atomic context" error.

Besides that serial8250_rpm_get() is called immediately after an IO just
happened. It implies that the device is already powered on, see implementation
of serial8250_em485_rts_after_send() and serial8250_clear_fifos() for the
details.

There is no bug have been seen due to, as I can guess, use of auto suspend mode
when scheduled transaction to suspend is invoked quite lately than it's needed
for a few writes to the port. It might be possible to trigger a warning if
stop_tx_timer fires when device is suspended.

Refactor the code to use runtime PM only in case of timer function.

Fixes: 0c66940d584d ("tty/serial/8250: fix RS485 half-duplex RX")
Cc: "Matwey V. Kornilov" 
Tested-by: Yegor Yefremov 
Signed-off-by: Andy Shevchenko 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_dw: Check the data->pclk when get apb_pclk

2016-10-22T10:40:21+00:00

commit e16b46f190a22587898b331f9d58583b0b166c9a upstream.

It should check the data->pclk, not data->clk when get apb_pclk.

Fixes: c8ed99d4f6a8("serial: 8250_dw: Add support for deferred probing")
Signed-off-by: Kefeng Wang 
Tested-by: Andy Shevchenko 
Signed-off-by: Greg Kroah-Hartman

BUG: atmel_serial: Interrupts not disabled on close

2016-10-22T10:40:21+00:00

commit 0ae9fdefb6c37237d826d6195e27810ffcc0b6e0 upstream.

Since commit 18dfef9c7f87 ("serial: atmel: convert to irq handling
provided mctrl-gpio"), interrupts from GPIOs are not disabled any more
when the serial port is closed, leading to an oops when the one of the
input pin is toggled (CTS/DSR/DCD/RNG).

This is only the case if those pins are used as GPIOs, i.e. declared
like that:
usart1: serial@f8020000 {
        /* CTS and DTS will be handled by GPIO */
        status = "okay";
        rts-gpios = <&pioB 17 GPIO_ACTIVE_LOW>;
        cts-gpios = <&pioB 16 GPIO_ACTIVE_LOW>;
        dtr-gpios = <&pioB 14 GPIO_ACTIVE_LOW>;
        dsr-gpios = <&pioC 31 GPIO_ACTIVE_LOW>;
        rng-gpios = <&pioB 12 GPIO_ACTIVE_LOW>;
        dcd-gpios = <&pioB 15 GPIO_ACTIVE_LOW>;
};

That's because modem interrupts used to be freed in atmel_shutdown().
After commit 18dfef9c7f87 ("serial: atmel: convert to irq handling
provided mctrl-gpio"), this code was just removed.
Calling atmel_disable_ms() disables the interrupts and everything works
fine again.

Tested on at91sam9g35-cm

(This patch doesn't apply on -stable kernels, fixes for 4.4 and 4.7 will
be sent after this one is applied.)

Signed-off-by: Richard Genoud 
Fixes: 18dfef9c7f87 ("serial: atmel: convert to irq handling provided mctrl-gpio")
Acked-by: Nicolas Ferre 
Acked-by: Uwe Kleine-König 
Signed-off-by: Greg Kroah-Hartman

serial: imx: Fix DCD reading

2016-10-22T10:40:21+00:00

commit 4b75f80003617fe35771a9e27022e8fbd6a41875 upstream.

The USR2_DCDIN bit is tested for in register usr1. As the name
suggests the usr2 register should be used instead. This fixes
reading the Carrier detect status.

Signed-off-by: Sascha Hauer 
Fixes: 90ebc4838666 ("serial: imx: repair and complete handshaking")
Acked-by: Uwe Kleine-König 
Reviewed-by: Fabio Estevam 
Signed-off-by: Greg Kroah-Hartman