linux-stable.git/drivers/tty, branch v4.4.121

serial: 8250_mid: fix broken DMA dependency

2018-02-25T10:03:49+00:00

commit 0ff4230584320b2153752ba54e2e8edbd6addf2c upstream.

In order to enable HSU DMA PCI driver, the HSU DMA Engine
must be enabled. This add a check for that.

Reported-by: kbuild test robot 
Signed-off-by: Heikki Krogerus 
Signed-off-by: Greg Kroah-Hartman

tty: cyclades: cyz_interrupt is only used for PCI

2018-02-25T10:03:48+00:00

commit 05ead49691d245f67bdd1b30cab5d9af522ac884 upstream.

When CONFIG_PCI is not set, enabling CONFIG_CYZ_INTR has no
practical effect other than generating a warning about an
unused function:

drivers/tty/cyclades.c:1184:20: warning: 'cyz_interrupt' defined but not used [-Wunused-function]
 static irqreturn_t cyz_interrupt(int irq, void *dev_id)

This adds a dependency to avoid that warning.

Signed-off-by: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

tty: hvc_xen: hide xen_console_remove when unused

2018-02-25T10:03:46+00:00

commit e36ae3439936e13c33f5841c7c2c1a9875acbb6d upstream.

xencons_disconnect_backend() is only called from xen_console_remove(),
which is conditionally compiled, so we get a harmless warning when
CONFIG_HVC_XEN_FRONTEND is unset:

hvc/hvc_xen.c:350:12: error: 'xen_console_remove' defined but not used [-Werror=unused-function]

This moves the function down into the same #ifdef section to silence
the warning.

Signed-off-by: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

serial: imx: Only wakeup via RTSDEN bit if the system has RTS/CTS

2018-02-03T16:04:30+00:00

commit 38b1f0fb42f772b8c9aac53593883a18ff5eb9d7 upstream.

The wakeup mechanism via RTSDEN bit relies on the system using the RTS/CTS
lines, so only allow such wakeup method when the system actually has
RTS/CTS support.

Fixes: bc85734b126f ("serial: imx: allow waking up on RTSD")
Signed-off-by: Fabio Estevam 
Reviewed-by: Martin Kaiser 
Acked-by: Fugang Duan 
Signed-off-by: Greg Kroah-Hartman

sysrq: Fix warning in sysrq generated crash.

2018-01-17T08:35:28+00:00

commit 984cf355aeaa8f2eda3861b50d0e8d3e3f77e83b upstream.

Commit 984d74a72076a1 ("sysrq: rcu-ify __handle_sysrq") replaced
spin_lock_irqsave() calls with rcu_read_lock() calls in sysrq. Since
rcu_read_lock() does not disable preemption, faulthandler_disabled() in
__do_page_fault() in x86/fault.c returns false. When the code later calls
might_sleep() in the pagefault handler, we get the following warning:

BUG: sleeping function called from invalid context at ../arch/x86/mm/fault.c:1187
in_atomic(): 0, irqs_disabled(): 0, pid: 4706, name: bash
Preemption disabled at:[] printk+0x48/0x4a

To fix this, we release the RCU read lock before we crash.

Tested this patch on linux 3.18 by booting off one of our boards.

Fixes: 984d74a72076a1 ("sysrq: rcu-ify __handle_sysrq")

Signed-off-by: Ani Sinha 
Reviewed-by: Rik van Riel 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Davidlohr Bueso 
Signed-off-by: Greg Kroah-Hartman

n_tty: fix EXTPROC vs ICANON interaction with TIOCINQ (aka FIONREAD)

2018-01-02T19:33:28+00:00

commit 966031f340185eddd05affcf72b740549f056348 upstream.

We added support for EXTPROC back in 2010 in commit 26df6d13406d ("tty:
Add EXTPROC support for LINEMODE") and the intent was to allow it to
override some (all?) ICANON behavior.  Quoting from that original commit
message:

         There is a new bit in the termios local flag word, EXTPROC.
         When this bit is set, several aspects of the terminal driver
         are disabled.  Input line editing, character echo, and mapping
         of signals are all disabled.  This allows the telnetd to turn
         off these functions when in linemode, but still keep track of
         what state the user wants the terminal to be in.

but the problem turns out that "several aspects of the terminal driver
are disabled" is a bit ambiguous, and you can really confuse the n_tty
layer by setting EXTPROC and then causing some of the ICANON invariants
to no longer be maintained.

This fixes at least one such case (TIOCINQ) becoming unhappy because of
the confusion over whether ICANON really means ICANON when EXTPROC is set.

This basically makes TIOCINQ match the case of read: if EXTPROC is set,
we ignore ICANON.  Also, make sure to reset the ICANON state ie EXTPROC
changes, not just if ICANON changes.

Fixes: 26df6d13406d ("tty: Add EXTPROC support for LINEMODE")
Reported-by: Tetsuo Handa 
Reported-by: syzkaller 
Cc: Jiri Slaby 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

sysrq : fix Show Regs call trace on ARM

2017-12-09T17:42:40+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

2017-12-09T17:42:40+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()

2017-12-09T17:42:39+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_pci: Add Amazon PCI serial device ID

2017-12-09T17:42:38+00:00

commit 3bfd1300abfe3adb18e84a89d97a0e82a22124bb upstream.

This device will be used in future Amazon EC2 instances as the primary
serial port (i.e., data sent to this port will be available via the
GetConsoleOuput [1] EC2 API).

[1] http://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_GetConsoleOutput.html

Signed-off-by: Matt Wilson 
Signed-off-by: Greg Kroah-Hartman