262 Commits

Author SHA1 Message Date
Lukas Wunner
26a2b9c468 serial: Deassert Transmit Enable on probe in driver-specific way
commit 7c7f9bc986e698873b489c371a08f206979d06b7 upstream.

When a UART port is newly registered, uart_configure_port() seeks to
deassert RS485 Transmit Enable by setting the RTS bit in port->mctrl.
However a number of UART drivers interpret a set RTS bit as *assertion*
instead of deassertion:  Affected drivers include those using
serial8250_em485_config() (except 8250_bcm2835aux.c) and some using
mctrl_gpio (e.g. imx.c).

Since the interpretation of the RTS bit is driver-specific, it is not
suitable as a means to centrally deassert Transmit Enable in the serial
core.  Instead, the serial core must call on drivers to deassert it in
their driver-specific way.  One way to achieve that is to call
->rs485_config().  It implicitly deasserts Transmit Enable.

So amend uart_configure_port() and uart_resume_port() to invoke
uart_rs485_config().  That allows removing calls to uart_rs485_config()
from drivers' ->probe() hooks and declaring the function static.

Skip any invocation of ->set_mctrl() if RS485 is enabled.  RS485 has no
hardware flow control, so the modem control lines are irrelevant and
need not be touched.  When leaving RS485 mode, reset the modem control
lines to the state stored in port->mctrl.  That way, UARTs which are
muxed between RS485 and RS232 transceivers drive the lines correctly
when switched to RS232.  (serial8250_do_startup() historically raises
the OUT1 modem signal because otherwise interrupts are not signaled on
ancient PC UARTs, but I believe that no longer applies to modern,
RS485-capable UARTs and is thus safe to be skipped.)

imx.c modifies port->mctrl whenever Transmit Enable is asserted and
deasserted.  Stop it from doing that so port->mctrl reflects the RS232
line state.

8250_omap.c deasserts Transmit Enable on ->runtime_resume() by calling
->set_mctrl().  Because that is now a no-op in RS485 mode, amend the
function to call serial8250_em485_stop_tx().

fsl_lpuart.c retrieves and applies the RS485 device tree properties
after registering the UART port.  Because applying now happens on
registration in uart_configure_port(), move retrieval of the properties
ahead of uart_add_one_port().

Link: https://lore.kernel.org/all/20220329085050.311408-1-matthias.schiffer@ew.tq-group.com/
Link: https://lore.kernel.org/all/8f538a8903795f22f9acc94a9a31b03c9c4ccacb.camel@ginzinger.com/
Fixes: d3b3404df318 ("serial: Fix incorrect rs485 polarity on uart open")
Cc: stable@vger.kernel.org # v4.14+
Reported-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reported-by: Roosen Henri <Henri.Roosen@ginzinger.com>
Tested-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/2de36eba3fbe11278d5002e4e501afe0ceaca039.1663863805.git.lukas@wunner.de
Signed-off-by: Daisuke Mizobuchi <mizo@atmark-techno.com>
Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-03 23:57:54 +09:00
Lino Sanfilippo
4a230f65d6 serial: core: move RS485 configuration tasks from drivers into core
commit 0ed12afa5655512ee418047fb3546d229df20aa1 upstream.

Several drivers that support setting the RS485 configuration via userspace
implement one or more of the following tasks:

- in case of an invalid RTS configuration (both RTS after send and RTS on
  send set or both unset) fall back to enable RTS on send and disable RTS
  after send

- nullify the padding field of the returned serial_rs485 struct

- copy the configuration into the uart port struct

- limit RTS delays to 100 ms

Move these tasks into the serial core to make them generic and to provide
a consistent behaviour among all drivers.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Link: https://lore.kernel.org/r/20220410104642.32195-2-LinoSanfilippo@gmx.de
Signed-off-by: Daisuke Mizobuchi <mizo@atmark-techno.com>
Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-03 23:57:54 +09:00
Ilpo Järvinen
d9cb6fabc9 serial: 8250: Fix PM usage_count for console handover
commit f9b11229b79c0fb2100b5bb4628a101b1d37fbf6 upstream.

When console is enabled, univ8250_console_setup() calls
serial8250_console_setup() before .dev is set to uart_port. Therefore,
it will not call pm_runtime_get_sync(). Later, when the actual driver
is going to take over univ8250_console_exit() is called. As .dev is
already set, serial8250_console_exit() makes pm_runtime_put_sync() call
with usage count being zero triggering PM usage count warning
(extra debug for univ8250_console_setup(), univ8250_console_exit(), and
serial8250_register_ports()):

[    0.068987] univ8250_console_setup ttyS0 nodev
[    0.499670] printk: console [ttyS0] enabled
[    0.717955] printk: console [ttyS0] printing thread started
[    1.960163] serial8250_register_ports assigned dev for ttyS0
[    1.976830] printk: console [ttyS0] disabled
[    1.976888] printk: console [ttyS0] printing thread stopped
[    1.977073] univ8250_console_exit ttyS0 usage:0
[    1.977075] serial8250 serial8250: Runtime PM usage count underflow!
[    1.977429] dw-apb-uart.6: ttyS0 at MMIO 0x4010006000 (irq = 33, base_baud = 115200) is a 16550A
[    1.977812] univ8250_console_setup ttyS0 usage:2
[    1.978167] printk: console [ttyS0] printing thread started
[    1.978203] printk: console [ttyS0] enabled

To fix the issue, call pm_runtime_get_sync() in
serial8250_register_ports() as soon as .dev is set for an uart_port
if it has console enabled.

This problem became apparent only recently because 82586a721595 ("PM:
runtime: Avoid device usage count underflows") added the warning
printout. I confirmed this problem also occurs with v5.18 (w/o the
warning printout, obviously).

Fixes: bedb404e91bb ("serial: 8250_port: Don't use power management for kernel console")
Cc: stable <stable@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/b4f428e9-491f-daf2-2232-819928dc276e@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-07-21 21:20:19 +02:00
Lukas Wunner
a1508d164e serial: core: Initialize rs485 RTS polarity already on probe
commit 2dd8a74fddd21b95dcc60a2d3c9eaec993419d69 upstream.

RTS polarity of rs485-enabled ports is currently initialized on uart
open via:

tty_port_open()
  tty_port_block_til_ready()
    tty_port_raise_dtr_rts()  # if (C_BAUD(tty))
      uart_dtr_rts()
        uart_port_dtr_rts()

There's at least three problems here:

First, if no baud rate is set, RTS polarity is not initialized.
That's the right thing to do for rs232, but not for rs485, which
requires that RTS is deasserted unconditionally.

Second, if the DeviceTree property "linux,rs485-enabled-at-boot-time" is
present, RTS should be deasserted as early as possible, i.e. on probe.
Otherwise it may remain asserted until first open.

Third, even though RTS is deasserted on open and close, it may
subsequently be asserted by uart_throttle(), uart_unthrottle() or
uart_set_termios() because those functions aren't rs485-aware.
(Only uart_tiocmset() is.)

To address these issues, move RTS initialization from uart_port_dtr_rts()
to uart_configure_port().  Prevent subsequent modification of RTS
polarity by moving the existing rs485 check from uart_tiocmget() to
uart_update_mctrl().

That way, RTS is initialized on probe and then remains unmodified unless
the uart transmits data.  If rs485 is enabled at runtime (instead of at
boot) through a TIOCSRS485 ioctl(), RTS is initialized by the uart
driver's ->rs485_config() callback and then likewise remains unmodified.

The PL011 driver initializes RTS on uart open and prevents subsequent
modification in its ->set_mctrl() callback.  That code is obsoleted by
the present commit, so drop it.

Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Su Bao Cheng <baocheng.su@siemens.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/2d2acaf3a69e89b7bf687c912022b11fd29dfa1e.1642909284.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-25 15:16:09 +02:00
Ilpo Järvinen
f65ba8b988 serial: 8250: fix XOFF/XON sending when DMA is used
[ Upstream commit f58c252e30cf74f68b0054293adc03b5923b9f0e ]

When 8250 UART is using DMA, x_char (XON/XOFF) is never sent
to the wire. After this change, x_char is injected correctly.

Create uart_xchar_out() helper for sending the x_char out and
accounting related to it. It seems that almost every driver
does these same steps with x_char. Except for 8250, however,
almost all currently lack .serial_out so they cannot immediately
take advantage of this new helper.

The downside of this patch is that it might reintroduce
the problems some devices faced with mixed DMA/non-DMA transfer
which caused revert f967fc8f165f (Revert "serial: 8250_dma:
don't bother DMA with small transfers"). However, the impact
should be limited to cases with XON/XOFF (that didn't work
with DMA capable devices to begin with so this problem is not
very likely to cause a major issue, if any at all).

Fixes: 9ee4b83e51f74 ("serial: 8250: Add support for dmaengine")
Reported-by: Gilles Buloz <gilles.buloz@kontron.com>
Tested-by: Gilles Buloz <gilles.buloz@kontron.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220314091432.4288-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-08 14:40:28 +02:00
Lukas Wunner
13518f058f serial: Fix incorrect rs485 polarity on uart open
commit d3b3404df318504ec084213ab1065b73f49b0f1d upstream.

Commit a6845e1e1b78 ("serial: core: Consider rs485 settings to drive
RTS") sought to deassert RTS when opening an rs485-enabled uart port.
That way, the transceiver does not occupy the bus until it transmits
data.

Unfortunately, the commit mixed up the logic and *asserted* RTS instead
of *deasserting* it:

The commit amended uart_port_dtr_rts(), which raises DTR and RTS when
opening an rs232 port.  "Raising" actually means lowering the signal
that's coming out of the uart, because an rs232 transceiver not only
changes a signal's voltage level, it also *inverts* the signal.  See
the simplified schematic in the MAX232 datasheet for an example:
https://www.ti.com/lit/ds/symlink/max232.pdf

So, to raise RTS on an rs232 port, TIOCM_RTS is *set* in port->mctrl
and that results in the signal being driven low.

In contrast to rs232, the signal level for rs485 Transmit Enable is the
identity, not the inversion:  If the transceiver expects a "high" RTS
signal for Transmit Enable, the signal coming out of the uart must also
be high, so TIOCM_RTS must be *cleared* in port->mctrl.

The commit did the exact opposite, but it's easy to see why given the
confusing semantics of rs232 and rs485.  Fix it.

Fixes: a6845e1e1b78 ("serial: core: Consider rs485 settings to drive RTS")
Cc: stable@vger.kernel.org # v4.14+
Cc: Rafael Gago Castano <rgc@hms.se>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Su Bao Cheng <baocheng.su@siemens.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/9395767847833f2f3193c49cde38501eeb3b5669.1639821059.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-01-27 10:54:25 +01:00
Lukas Wunner
f8fdebfb4b serial: core: Keep mctrl register state and cached copy in sync
[ Upstream commit 93a770b7e16772530196674ffc79bb13fa927dc6 ]

struct uart_port contains a cached copy of the Modem Control signals.
It is used to skip register writes in uart_update_mctrl() if the new
signal state equals the old signal state.  It also avoids a register
read to obtain the current state of output signals.

When a uart_port is registered, uart_configure_port() changes signal
state but neglects to keep the cached copy in sync.  That may cause
a subsequent register write to be incorrectly skipped.  Fix it before
it trips somebody up.

This behavior has been present ever since the serial core was introduced
in 2002:
https://git.kernel.org/history/history/c/33c0d1b0c3eb

So far it was never an issue because the cached copy is initialized to 0
by kzalloc() and when uart_configure_port() is executed, at most DTR has
been set by uart_set_options() or sunsu_console_setup().  Therefore,
a stable designation seems unnecessary.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/bceeaba030b028ed810272d55d5fc6f3656ddddb.1641129752.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-01-27 10:54:20 +01:00
Lukas Wunner
a5d0a72b80 serial: 8250: Fix RTS modem control while in rs485 mode
commit f85e04503f369b3f2be28c83fc48b74e19936ebc upstream.

Commit f45709df7731 ("serial: 8250: Don't touch RTS modem control while
in rs485 mode") sought to prevent user space from interfering with rs485
communication by ignoring a TIOCMSET ioctl() which changes RTS polarity.

It did so in serial8250_do_set_mctrl(), which turns out to be too deep
in the call stack:  When a uart_port is opened, RTS polarity is set by
the rs485-aware function uart_port_dtr_rts().  It calls down to
serial8250_do_set_mctrl() and that particular RTS polarity change should
*not* be ignored.

The user-visible result is that on 8250_omap ports which use rs485 with
inverse polarity (RTS bit in MCR register is 1 to receive, 0 to send),
a newly opened port initially sets up RTS for sending instead of
receiving.  That's because omap_8250_startup() sets the cached value
up->mcr to 0 and omap_8250_restore_regs() subsequently writes it to the
MCR register.  Due to the commit, serial8250_do_set_mctrl() preserves
that incorrect register value:

do_sys_openat2
  do_filp_open
    path_openat
      vfs_open
        do_dentry_open
	  chrdev_open
	    tty_open
	      uart_open
	        tty_port_open
		  uart_port_activate
		    uart_startup
		      uart_port_startup
		        serial8250_startup
			  omap_8250_startup # up->mcr = 0
			uart_change_speed
			  serial8250_set_termios
			    omap_8250_set_termios
			      omap_8250_restore_regs
			        serial8250_out_MCR # up->mcr written
		  tty_port_block_til_ready
		    uart_dtr_rts
		      uart_port_dtr_rts
		        serial8250_set_mctrl
			  omap8250_set_mctrl
			    serial8250_do_set_mctrl # mcr[1] = 1 ignored

Fix by intercepting RTS changes from user space in uart_tiocmset()
instead.

Link: https://lore.kernel.org/linux-serial/20211027111644.1996921-1-baocheng.su@siemens.com/
Fixes: f45709df7731 ("serial: 8250: Don't touch RTS modem control while in rs485 mode")
Cc: Chao Zeng <chao.zeng@siemens.com>
Cc: stable@vger.kernel.org # v5.7+
Reported-by: Su Bao Cheng <baocheng.su@siemens.com>
Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Tested-by: Su Bao Cheng <baocheng.su@siemens.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/21170e622a1aaf842a50b32146008b5374b3dd1d.1637596432.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-08 09:03:29 +01:00
Johan Hovold
e1722acf4f serial: core: fix transmit-buffer reset and memleak
commit 00de977f9e0aa9760d9a79d1e41ff780f74e3424 upstream.

Commit 761ed4a94582 ("tty: serial_core: convert uart_close to use
tty_port_close") converted serial core to use tty_port_close() but
failed to notice that the transmit buffer still needs to be freed on
final close.

Not freeing the transmit buffer means that the buffer is no longer
cleared on next open so that any ioctl() waiting for the buffer to drain
might wait indefinitely (e.g. on termios changes) or that stale data can
end up being transmitted in case tx is restarted.

Furthermore, the buffer of any port that has been opened would leak on
driver unbind.

Note that the port lock is held when clearing the buffer pointer due to
the ldisc race worked around by commit a5ba1d95e46e ("uart: fix race
between uart_put_char() and uart_shutdown()").

Also note that the tty-port shutdown() callback is not called for
console ports so it is not strictly necessary to free the buffer page
after releasing the lock (cf. d72402145ace ("tty/serial: do not free
trasnmit buffer page under port lock")).

Link: https://lore.kernel.org/r/319321886d97c456203d5c6a576a5480d07c3478.1635781688.git.baruch@tkos.co.il
Fixes: 761ed4a94582 ("tty: serial_core: convert uart_close to use tty_port_close")
Cc: stable@vger.kernel.org      # 4.9
Cc: Rob Herring <robh@kernel.org>
Reported-by: Baruch Siach <baruch@tkos.co.il>
Tested-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20211108085431.12637-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-08 09:03:29 +01:00
Pali Rohár
47462c5e60 serial: core: Fix initializing and restoring termios speed
commit 027b57170bf8bb6999a28e4a5f3d78bf1db0f90c upstream.

Since commit edc6afc54968 ("tty: switch to ktermios and new framework")
termios speed is no longer stored only in c_cflag member but also in new
additional c_ispeed and c_ospeed members. If BOTHER flag is set in c_cflag
then termios speed is stored only in these new members.

Therefore to correctly restore termios speed it is required to store also
ispeed and ospeed members, not only cflag member.

In case only cflag member with BOTHER flag is restored then functions
tty_termios_baud_rate() and tty_termios_input_baud_rate() returns baudrate
stored in c_ospeed / c_ispeed member, which is zero as it was not restored
too. If reported baudrate is invalid (e.g. zero) then serial core functions
report fallback baudrate value 9600. So it means that in this case original
baudrate is lost and kernel changes it to value 9600.

Simple reproducer of this issue is to boot kernel with following command
line argument: "console=ttyXXX,86400" (where ttyXXX is the device name).
For speed 86400 there is no Bnnn constant and therefore kernel has to
represent this speed via BOTHER c_cflag. Which means that speed is stored
only in c_ospeed and c_ispeed members, not in c_cflag anymore.

If bootloader correctly configures serial device to speed 86400 then kernel
prints boot log to early console at speed speed 86400 without any issue.
But after kernel starts initializing real console device ttyXXX then speed
is changed to fallback value 9600 because information about speed was lost.

This patch fixes above issue by storing and restoring also ispeed and
ospeed members, which are required for BOTHER flag.

Fixes: edc6afc54968 ("[PATCH] tty: switch to ktermios and new framework")
Cc: stable@vger.kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Link: https://lore.kernel.org/r/20211002130900.9518-1-pali@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-18 14:03:49 +01:00
Ondrej Mosnacek
1a2494c9eb serial: core: fix suspicious security_locked_down() call
commit 5e722b217ad3cf41f5504db80a68062df82b5242 upstream.

The commit that added this check did so in a very strange way - first
security_locked_down() is called, its value stored into retval, and if
it's nonzero, then an additional check is made for (change_irq ||
change_port), and if this is true, the function returns. However, if
the goto exit branch is not taken, the code keeps the retval value and
continues executing the function. Then, depending on whether
uport->ops->verify_port is set, the retval value may or may not be reset
to zero and eventually the error value from security_locked_down() may
abort the function a few lines below.

I will go out on a limb and assume that this isn't the intended behavior
and that an error value from security_locked_down() was supposed to
abort the function only in case (change_irq || change_port) is true.

Note that security_locked_down() should be called last in any series of
checks, since the SELinux implementation of this hook will do a check
against the policy and generate an audit record in case of denial. If
the operation was to carry on after calling security_locked_down(), then
the SELinux denial record would be bogus.

See commit 59438b46471a ("security,lockdown,selinux: implement SELinux
lockdown") for how SELinux implements this hook.

Fixes: 794edf30ee6c ("lockdown: Lock down TIOCSSERIAL")
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210507115719.140799-1-omosnace@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-03 09:00:32 +02:00
Johan Hovold
26882a15ed serial: core: return early on unsupported ioctls
[ Upstream commit 79c5966cec7b148199386ef9933c31b999379065 ]

Drivers can return -ENOIOCTLCMD when an ioctl is not recognised to tell
the upper layers to continue looking for a handler.

This is not the case for the RS485 and ISO7816 ioctls whose handlers
should return -ENOTTY directly in case a serial driver does not
implement the corresponding methods.

Fixes: a5f276f10ff7 ("serial_core: Handle TIOC[GS]RS485 ioctls.")
Fixes: ad8c0eaa0a41 ("tty/serial_core: add ISO7816 infrastructure")
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407095208.31838-9-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-14 09:50:19 +02:00
Alexey Kardashevskiy
e6160ad6e7 serial_core: Check for port state when tty is in error state
commit 2f70e49ed860020f5abae4f7015018ebc10e1f0e upstream.

At the moment opening a serial device node (such as /dev/ttyS3)
succeeds even if there is no actual serial device behind it.
Reading/writing/ioctls fail as expected because the uart port is not
initialized (the type is PORT_UNKNOWN) and the TTY_IO_ERROR error state
bit is set fot the tty.

However setting line discipline does not have these checks
8250_port.c (8250 is the default choice made by univ8250_console_init()).
As the result of PORT_UNKNOWN, uart_port::iobase is NULL which
a platform translates onto some address accessing which produces a crash
like below.

This adds tty_port_initialized() to uart_set_ldisc() to prevent the crash.

Found by syzkaller.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Link: https://lore.kernel.org/r/20201203055834.45838-1-aik@ozlabs.ru
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-26 16:02:43 +01:00
Greg Kroah-Hartman
33f16b25a0 Merge 5.9.0-rc6 into tty-next
We need the tty/serial fixes in here and this resolves a merge issue in
the 8250 driver.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-21 09:23:55 +02:00
Johan Hovold
e0830dbf71 serial: core: fix console port-lock regression
Fix the port-lock initialisation regression introduced by commit
a3cb39d258ef ("serial: core: Allow detach and attach serial device for
console") by making sure that the lock is again initialised during
console setup.

The console may be registered before the serial controller has been
probed in which case the port lock needs to be initialised during
console setup by a call to uart_set_options(). The console-detach
changes introduced a regression in several drivers by effectively
removing that initialisation by not initialising the lock when the port
is used as a console (which is always the case during console setup).

Add back the early lock initialisation and instead use a new
console-reinit flag to handle the case where a console is being
re-attached through sysfs.

The question whether the console-detach interface should have been added
in the first place is left for another discussion.

Note that the console-enabled check in uart_set_options() is not
redundant because of kgdboc, which can end up reinitialising an already
enabled console (see commit 42b6a1baa3ec ("serial_core: Don't
re-initialize a previously initialized spinlock.")).

Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console")
Cc: stable <stable@vger.kernel.org>     # 5.7
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200909143101.15389-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-16 13:22:44 +02:00
Johan Hovold
fe88c64892 serial: core: fix port-lock initialisation
Commit f743061a85f5 ("serial: core: Initialise spin lock before use in
uart_configure_port()") tried to work around a breakage introduced by
commit a3cb39d258ef ("serial: core: Allow detach and attach serial
device for console") by adding a second initialisation of the port lock
when registering the port.

As reported by the build robots [1], this doesn't really solve the
regression introduced by the console-detach changes and also adds a
second redundant initialisation of the lock for normal ports.

Start cleaning up this mess by removing the redundant initialisation and
making sure that the port lock is again initialised once-only for ports
that aren't already in use as a console.

[1] https://lore.kernel.org/r/20200802054852.GR23458@shao2-debian

Fixes: f743061a85f5 ("serial: core: Initialise spin lock before use in uart_configure_port()")
Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console")
Cc: stable <stable@vger.kernel.org>     # 5.7
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200909143101.15389-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-16 13:22:10 +02:00
Krzysztof Kozlowski
89c65d6648 serial: core: Simplify with dev_err_probe()
Common pattern of handling deferred probe can be simplified with
dev_err_probe().  Less code and the error value gets printed.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/20200901153100.18827-2-krzk@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-04 17:14:31 +02:00
Greg Kroah-Hartman
8f49a2fe8e Linux 5.9-rc3
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Merge 5.9-rc3 into tty-next

We need the tty/serial fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-31 07:19:25 +02:00
Alex Dewar
9cfbf7a641 serial: core: don't use snprintf() for formatting sysfs attrs
As per the documentation (Documentation/filesystems/sysfs.rst),
snprintf() should not be used for formatting values returned by sysfs.

For all of the instances in serial_core.c, we know that the string will
be <PAGE_SIZE in length, so just use sprintf().

Issue identified by Coccinelle.

Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
Link: https://lore.kernel.org/r/20200824223932.27709-1-alex.dewar90@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-28 10:26:47 +02:00
Gustavo A. R. Silva
df561f6688 treewide: Use fallthrough pseudo-keyword
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-23 17:36:59 -05:00
Tamseel Shams
4ed71addf5 serial: core: Fix Coding Style
This patch fixes the following checkpatch error and warning:
  1. space required after ','
  2. Missing a blank line after declarations

Signed-off-by: Tamseel Shams <m.shams@samsung.com>
Link: https://lore.kernel.org/r/20200716115438.9967-1-m.shams@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-21 20:04:54 +02:00
Greg Kroah-Hartman
6f2c6599ba Linux 5.8-rc6
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Merge 5.8-rc6 into tty-next

We need the serial/tty fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-20 09:39:11 +02:00
Andy Shevchenko
f743061a85 serial: core: Initialise spin lock before use in uart_configure_port()
The comment near to uart_port_spin_lock_init() says:

  Ensure that the serial console lock is initialised early.
  If this port is a console, then the spinlock is already initialised.

and there is nothing about enabled or disabled consoles. The commit
a3cb39d258ef ("serial: core: Allow detach and attach serial device
for console") made a change, which follows the comment, and also to
prevent reinitialisation of the lock in use, when user detaches and
attaches back the same console device. But this change discovers
another issue, that uart_add_one_port() tries to access a spin lock
that now may be uninitialised. This happens when a driver expects
the serial core to register a console on its behalf. In this case
we must initialise a spin lock before use.

Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console")
Reported-by: Marc Zyngier <maz@kernel.org>
Reported-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Reported-by: Anatoly Pugachev <matorola@gmail.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20200706214903.56148-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-10 14:44:46 +02:00
Johan Hovold
08d5470308 serial: core: fix sysrq overhead regression
Commit 8e20fc391711 ("serial_core: Move sysrq functions from header
file") converted the inline sysrq helpers to exported functions which
are now called for every received character, interrupt and break signal
also on systems without CONFIG_MAGIC_SYSRQ_SERIAL instead of being
optimised away by the compiler.

Inlining these helpers again also avoids the function call overhead when
CONFIG_MAGIC_SYSRQ_SERIAL is enabled (e.g. when the port is not used as
a console).

Fixes: 8e20fc391711 ("serial_core: Move sysrq functions from header file")
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Link: https://lore.kernel.org/r/20200610152232.16925-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-27 16:16:37 +02:00
Johan Hovold
10652a9e9f Revert "serial: core: Refactor uart_unlock_and_check_sysrq()"
This reverts commit da9a5aa3402db0ff3b57216d8dbf2478e1046cae.

In order to ease backporting a fix for a sysrq regression, revert this
rewrite which was since added on top.

The other sysrq helpers now bail out early when sysrq is not enabled;
it's better to keep that pattern here as well.

Note that the __releases() attribute won't be needed after the follow-on
fix either.

Fixes: da9a5aa3402d ("serial: core: Refactor uart_unlock_and_check_sysrq()")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200610152232.16925-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-27 16:16:37 +02:00
Johan Hovold
167cbce274 serial: core: drop unnecessary gpio include
Drop the recently added gpio include from the serial-core header in
favour of a forward declaration and instead include the gpio header only
where needed.

Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20200610155121.14014-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-27 16:12:45 +02:00
Randy Dunlap
a71725619f tty/serial: fix serial_core.c kernel-doc warnings
Fix kernel-doc warnings in serial_core.c:

../drivers/tty/serial/serial_core.c:3300: warning: Function parameter or member 'port' not described in 'uart_get_rs485_mode'
../drivers/tty/serial/serial_core.c:3300: warning: Excess function parameter 'dev' description in 'uart_get_rs485_mode'
../drivers/tty/serial/serial_core.c:3300: warning: Excess function parameter 'rs485conf' description in 'uart_get_rs485_mode'

Fixes: c150c0f362c1 ("serial: Allow uart_get_rs485_mode() to return errno")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-serial@vger.kernel.org
Link: https://lore.kernel.org/r/e170db8e-5c8b-27ac-79a4-81b96ac0ca2d@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-27 13:56:39 +02:00
Lukas Wunner
d58a2df3d8 serial: 8250: Support rs485 bus termination GPIO
Commit e8759ad17d41 ("serial: uapi: Add support for bus termination")
introduced the ability to enable rs485 bus termination from user space.
So far the feature is only used by a single driver, 8250_exar.c, using a
hardcoded GPIO pin specific to Siemens IOT2040 products.

Provide for a more generic solution by allowing specification of an
rs485 bus termination GPIO pin in the device tree:  Amend the serial
core to retrieve the GPIO from the device tree (or ACPI table) and amend
the default ->rs485_config() callback for 8250 drivers to change the
GPIO on request from user space.

Perhaps 8250_exar.c can be converted to the generic approach in a
follow-up patch.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Link: https://lore.kernel.org/r/94c6c800d1ca9fa04766dd1d43a8272c5ad4bedd.1589811297.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-29 12:42:54 +02:00
Lukas Wunner
c150c0f362 serial: Allow uart_get_rs485_mode() to return errno
We're about to amend uart_get_rs485_mode() to support a GPIO pin for
rs485 bus termination.  Retrieving the GPIO descriptor may fail, so
allow uart_get_rs485_mode() to return an errno and change all callers
to check for failure.

The GPIO descriptor is going to be stored in struct uart_port.  Pass
that struct to uart_get_rs485_mode() in lieu of a struct device and
struct serial_rs485, both of which are directly accessible from struct
uart_port.

A few drivers call uart_get_rs485_mode() before setting the struct
device pointer in struct uart_port.  Shuffle those calls around where
necessary.

[Heiko Stuebner did the ar933x_uart.c portion, hence his Signed-off-by.]

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/271e814af4b0db3bffbbb74abf2b46b75add4516.1589285873.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-15 14:47:05 +02:00
Andy Shevchenko
a3cb39d258 serial: core: Allow detach and attach serial device for console
In the future we would like to disable power management on the serial devices
used as kernel consoles to avoid weird behaviour in some cases. However,
disabling PM may prevent system to go to deep sleep states, which in its turn
leads to the higher power consumption.

Tony Lindgren proposed a work around, i.e. allow user to detach such consoles
to make PM working again. In case user wants to see what's going on, it also
provides a mechanism to attach console back.

Link: https://lists.openwall.net/linux-kernel/2018/09/29/65
Suggested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200217114016.49856-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-17 15:57:59 +01:00
Andy Shevchenko
da9a5aa340 serial: core: Refactor uart_unlock_and_check_sysrq()
Refactor uart_unlock_and_check_sysrq() to:

  - explicitly show that we release a port lock which makes
    static analyzers happy:

CHECK   drivers/tty/serial/serial_core.c
.../serial_core.c:3290:17: warning: context imbalance in 'uart_unlock_and_check_sysrq' - unexpected unlock

  - use flags instead of irqflags to avoid confusion with IRQ flags

  - provide one return point

  - be more compact

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Link: https://lore.kernel.org/r/20200310174337.74109-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-12 17:16:42 +01:00
Andy Shevchenko
e140ef3692 serial: core: Use uart_console() helper in SysRq code
Use uart_console() helper in SysRq code instead of open coded variant.
This eliminates the conditional entirely for SERIAL_CORE_CONSOLE=n case.
While here, refactor the conditional to be more compact.

Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200310174337.74109-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-12 17:16:41 +01:00
Andy Shevchenko
b18896ff3a serial: core: Print escaped SysRq Magic sequence if enabled
It is useful to see on the serial console the magic sequence itself
to enable SysRq without rummaging source code.

Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200310174337.74109-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-12 17:16:41 +01:00
Andy Shevchenko
2ce5eace42 serial: core: Use string length for SysRq magic sequence
Compiler is not happy about using ARRAY_SIZE() in comparison to smaller type:

  CC      drivers/tty/serial/serial_core.o
.../serial_core.c: In function ‘uart_try_toggle_sysrq’:
.../serial_core.c:3222:24: warning: comparison is always false due to limited range of data type [-Wtype-limits]
 3222 |  if (++port->sysrq_seq < (ARRAY_SIZE(sysrq_toggle_seq) - 1)) {
      |                        ^

Looking at the code it appears that there is an additional weirdness,
i.e. use ARRAY_SIZE() against simple string literal. Yes, the idea probably
was to allow '\0' in the sequence, but it's impractical: kernel configuration
won't accept it to begin with followed by a comment about '\0' before
comparison in question.

Drop all these by switching to strlen() and convert code accordingly.

Note, GCC seems clever enough to calculate string length at compile time.

Fixes: 68af43173d3f ("serial/sysrq: Add MAGIC_SYSRQ_SERIAL_SEQUENCE")
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200310174337.74109-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-12 17:16:41 +01:00
Dmitry Safonov
68af43173d serial/sysrq: Add MAGIC_SYSRQ_SERIAL_SEQUENCE
Many embedded boards have a disconnected TTL level serial which can
generate some garbage that can lead to spurious false sysrq detects.

Currently, sysrq can be either completely disabled for serial console
or always disabled (with CONFIG_MAGIC_SYSRQ_SERIAL), since
commit 732dbf3a6104 ("serial: do not accept sysrq characters via serial port")

At Arista, we have such boards that can generate BREAK and random
garbage. While disabling sysrq for serial console would solve
the problem with spurious false sysrq triggers, it's also desirable
to have a way to enable sysrq back.

As a measure of balance between on and off options, add
MAGIC_SYSRQ_SERIAL_SEQUENCE which is a string sequence that can enable
sysrq if it follows BREAK on a serial line. The longer the string - the
less likely it may be in the garbage.

Having the way to enable sysrq was beneficial to debug lockups with
a manual investigation in field and on the other side preventing false
sysrq detections.

Based-on-patch-by: Vasiliy Khoruzhick <vasilykh@arista.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20200302175135.269397-3-dima@arista.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-07 09:52:02 +01:00
Andy Shevchenko
143c02c88d serial: core: Switch to use DEVICE_ATTR_RO()
Move device attributes to DEVICE_ATTR_RO() as that would make things
a lot more "obvious" what is happening here.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200217114016.49856-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-17 17:01:54 +01:00
Andy Shevchenko
643f7d95fe serial: core: use octal permissions on module param
Symbolic permissions 'S_IRUSR | S_IRGRP' are not preferred.
Use octal permissions '0440'. This also makes code shorter.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200214114339.53897-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-14 08:34:18 -08:00
Andy Shevchenko
d2403cadc1 serial: core: Consolidate spin lock initialization code
We have two times duplicated excerpt where we initialize spin lock
for UART port. Consolidate it under uart_port_spin_lock_init() helper.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200214114339.53897-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-14 08:34:18 -08:00
Andy Shevchenko
7a49955af1 serial: core: Introduce uart_console_enabled() helper
Introduce uart_console_enabled() helper which checks port to be console
and console is registered in the list.

Note, this helper will be used in the future as well.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200214114339.53897-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-14 08:34:18 -08:00
Dmitry Safonov
8e20fc3917 serial_core: Move sysrq functions from header file
It's not worth to have them in every serial driver and I'm about to add
another helper function.

Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20200109215444.95995-2-dima@arista.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-10 17:48:02 +01:00
John Stultz
488f49acec tty: serial_core: Export uart_console_device so it can be used by modules
In order to support serial console w/ SERIAL_QCOM_GENI=m,
we need to export the uart_console_device() symbol so things
will build

Cc: Todd Kjos <tkjos@google.com>
Cc: Alistair Delva <adelva@google.com>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/r/20200107010311.58584-1-john.stultz@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-10 14:01:32 +01:00
Sudip Mukherjee
fb2b90014d tty: link tty and port before configuring it as console
There seems to be a race condition in tty drivers and I could see on
many boot cycles a NULL pointer dereference as tty_init_dev() tries to
do 'tty->port->itty = tty' even though tty->port is NULL.
'tty->port' will be set by the driver and if the driver has not yet done
it before we open the tty device we can get to this situation. By adding
some extra debug prints, I noticed that:

6.650130: uart_add_one_port
6.663849: register_console
6.664846: tty_open
6.674391: tty_init_dev
6.675456: tty_port_link_device

uart_add_one_port() registers the console, as soon as it registers, the
userspace tries to use it and that leads to tty_open() but
uart_add_one_port() has not yet done tty_port_link_device() and so
tty->port is not yet configured when control reaches tty_init_dev().

Further look into the code and tty_port_link_device() is done by
uart_add_one_port(). After registering the console uart_add_one_port()
will call tty_port_register_device_attr_serdev() and
tty_port_link_device() is called from this.

Call add tty_port_link_device() before uart_configure_port() is done and
add a check in tty_port_link_device() so that it only links the port if
it has not been done yet.

Suggested-by: Jiri Slaby <jslaby@suse.com>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191212131602.29504-1-sudipm.mukherjee@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-17 14:12:34 +01:00
Jiangfeng Xiao
7d73170e1c serial: serial_core: Perform NULL checks for break_ctl ops
Doing fuzz test on sbsa uart device, causes a kernel crash
due to NULL pointer dereference:

------------[ cut here ]------------
Unable to handle kernel paging request at virtual address fffffffffffffffc
pgd = ffffffe331723000
[fffffffffffffffc] *pgd=0000002333595003, *pud=0000002333595003, *pmd=00000
Internal error: Oops: 96000005 [#1] PREEMPT SMP
Modules linked in: ping(O) jffs2 rtos_snapshot(O) pramdisk(O) hisi_sfc(O)
Drv_Nandc_K(O) Drv_SysCtl_K(O) Drv_SysClk_K(O) bsp_reg(O) hns3(O)
hns3_uio_enet(O) hclgevf(O) hclge(O) hnae3(O) mdio_factory(O)
mdio_registry(O) mdio_dev(O) mdio(O) hns3_info(O) rtos_kbox_panic(O)
uart_suspend(O) rsm(O) stp llc tunnel4 xt_tcpudp ipt_REJECT nf_reject_ipv4
iptable_filter ip_tables x_tables sd_mod xhci_plat_hcd xhci_pci xhci_hcd
usbmon usbhid usb_storage ohci_platform ohci_pci ohci_hcd hid_generic hid
ehci_platform ehci_pci ehci_hcd vfat fat usbcore usb_common scsi_mod
yaffs2multi(O) ext4 jbd2 ext2 mbcache ofpart i2c_dev i2c_core uio ubi nand
nand_ecc nand_ids cfi_cmdset_0002 cfi_cmdset_0001 cfi_probe gen_probe
cmdlinepart chipreg mtdblock mtd_blkdevs mtd nfsd auth_rpcgss oid_registry
nfsv3 nfs nfs_acl lockd sunrpc grace autofs4
CPU: 2 PID: 2385 Comm: tty_fuzz_test Tainted: G           O    4.4.193 #1
task: ffffffe32b23f110 task.stack: ffffffe32bda4000
PC is at uart_break_ctl+0x44/0x84
LR is at uart_break_ctl+0x34/0x84
pc : [<ffffff8393196098>] lr : [<ffffff8393196088>] pstate: 80000005
sp : ffffffe32bda7cc0
x29: ffffffe32bda7cc0 x28: ffffffe32b23f110
x27: ffffff8393402000 x26: 0000000000000000
x25: ffffffe32b233f40 x24: ffffffc07a8ec680
x23: 0000000000005425 x22: 00000000ffffffff
x21: ffffffe33ed73c98 x20: 0000000000000000
x19: ffffffe33ed94168 x18: 0000000000000004
x17: 0000007f92ae9d30 x16: ffffff8392fa6064
x15: 0000000000000010 x14: 0000000000000000
x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000020 x10: 0000007ffdac1708
x9 : 0000000000000078 x8 : 000000000000001d
x7 : 0000000052a64887 x6 : ffffffe32bda7e08
x5 : ffffffe32b23c000 x4 : 0000005fbc5b0000
x3 : ffffff83938d5018 x2 : 0000000000000080
x1 : ffffffe32b23c040 x0 : ffffff83934428f8
virtual start addr offset is 38ac00000
module base offset is 2cd4cf1000
linear region base offset is : 0
Process tty_fuzz_test (pid: 2385, stack limit = 0xffffffe32bda4000)
Stack: (0xffffffe32bda7cc0 to 0xffffffe32bda8000)
7cc0: ffffffe32bda7cf0 ffffff8393177718 ffffffc07a8ec680 ffffff8393196054
7ce0: 000000001739f2e0 0000007ffdac1978 ffffffe32bda7d20 ffffff8393179a1c
7d00: 0000000000000000 ffffff8393c0a000 ffffffc07a8ec680 cb88537fdc8ba600
7d20: ffffffe32bda7df0 ffffff8392fa5a40 ffffff8393c0a000 0000000000005425
7d40: 0000007ffdac1978 ffffffe32b233f40 ffffff8393178dcc 0000000000000003
7d60: 000000000000011d 000000000000001d ffffffe32b23f110 000000000000029e
7d80: ffffffe34fe8d5d0 0000000000000000 ffffffe32bda7e14 cb88537fdc8ba600
7da0: ffffffe32bda7e30 ffffff8393042cfc ffffff8393c41720 ffffff8393c46410
7dc0: ffffff839304fa68 ffffffe32b233f40 0000000000005425 0000007ffdac1978
7de0: 000000000000011d cb88537fdc8ba600 ffffffe32bda7e70 ffffff8392fa60cc
7e00: 0000000000000000 ffffffe32b233f40 ffffffe32b233f40 0000000000000003
7e20: 0000000000005425 0000007ffdac1978 ffffffe32bda7e70 ffffff8392fa60b0
7e40: 0000000000000280 ffffffe32b233f40 ffffffe32b233f40 0000000000000003
7e60: 0000000000005425 cb88537fdc8ba600 0000000000000000 ffffff8392e02e78
7e80: 0000000000000280 0000005fbc5b0000 ffffffffffffffff 0000007f92ae9d3c
7ea0: 0000000060000000 0000000000000015 0000000000000003 0000000000005425
7ec0: 0000007ffdac1978 0000000000000000 00000000a54c910e 0000007f92b95014
7ee0: 0000007f92b95090 0000000052a64887 000000000000001d 0000000000000078
7f00: 0000007ffdac1708 0000000000000020 0000000000000000 0000000000000000
7f20: 0000000000000000 0000000000000010 000000556acf0090 0000007f92ae9d30
7f40: 0000000000000004 000000556acdef10 0000000000000000 000000556acdebd0
7f60: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
7f80: 0000000000000000 0000000000000000 0000000000000000 0000007ffdac1840
7fa0: 000000556acdedcc 0000007ffdac1840 0000007f92ae9d3c 0000000060000000
7fc0: 0000000000000000 0000000000000000 0000000000000003 000000000000001d
7fe0: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
Call trace:
Exception stack(0xffffffe32bda7ab0 to 0xffffffe32bda7bf0)
7aa0:                                   0000000000001000 0000007fffffffff
7ac0: ffffffe32bda7cc0 ffffff8393196098 0000000080000005 0000000000000025
7ae0: ffffffe32b233f40 ffffff83930d777c ffffffe32bda7b30 ffffff83930d777c
7b00: ffffffe32bda7be0 ffffff83938d5000 ffffffe32bda7be0 ffffffe32bda7c20
7b20: ffffffe32bda7b60 ffffff83930d777c ffffffe32bda7c10 ffffff83938d5000
7b40: ffffffe32bda7c10 ffffffe32bda7c50 ffffff8393c0a000 ffffffe32b23f110
7b60: ffffffe32bda7b70 ffffff8392e09df4 ffffffe32bda7bb0 cb88537fdc8ba600
7b80: ffffff83934428f8 ffffffe32b23c040 0000000000000080 ffffff83938d5018
7ba0: 0000005fbc5b0000 ffffffe32b23c000 ffffffe32bda7e08 0000000052a64887
7bc0: 000000000000001d 0000000000000078 0000007ffdac1708 0000000000000020
7be0: 0000000000000000 0000000000000000
[<ffffff8393196098>] uart_break_ctl+0x44/0x84
[<ffffff8393177718>] send_break+0xa0/0x114
[<ffffff8393179a1c>] tty_ioctl+0xc50/0xe84
[<ffffff8392fa5a40>] do_vfs_ioctl+0xc4/0x6e8
[<ffffff8392fa60cc>] SyS_ioctl+0x68/0x9c
[<ffffff8392e02e78>] __sys_trace_return+0x0/0x4
Code: b9410ea0 34000160 f9408aa0 f9402814 (b85fc280)
---[ end trace 8606094f1960c5e0 ]---
Kernel panic - not syncing: Fatal exception

Fix this problem by adding NULL checks prior to calling break_ctl ops.

Signed-off-by: Jiangfeng Xiao <xiaojiangfeng@huawei.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1574263133-28259-1-git-send-email-xiaojiangfeng@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-21 08:24:43 +01:00
Michal Simek
dd8b7a1db5 Revert "serial: core: Use cons->index for preferred console registration"
This reverts commit 91daae03188e0dd1da3c1b599df4ce7539d5a69f.

The origin patch is causing an issue on r8a7791/koelsch and
r8a7795/salvator-xs platforms where cons->index is not initialized to
expected value.
It is safer to revert this patch for now till it is clear why this is
happening.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/59f51af6bb03fce823663764d17ad0291aa01ab2.1571222199.git.michal.simek@xilinx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-16 04:05:24 -07:00
Greg Kroah-Hartman
7ca932e441 Merge 5.4-rc3 into tty-next
We need the tty/serial fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-14 07:32:24 +02:00
Randy Dunlap
ff30283a8d serial: fix kernel-doc warning in comments
Fix Sphinx warning in serial_core.c:

../drivers/tty/serial/serial_core.c:1969: WARNING: Definition list ends without a blank line; unexpected unindent.

Fixes: 73abaf87f01b ("serial: earlycon: Refactor parse_options into serial core")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/e989641c-224a-1090-e596-e7cc800bed44@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-10 13:12:28 +02:00
Michal Simek
91daae0318 serial: core: Use cons->index for preferred console registration
The reason for this patch is xilinx_uartps driver which create one dynamic
instance per IP with unique major and minor combinations. drv->nr is in
this case all the time setup to 1. That means that uport->line is all the
time setup to 0 and drv->tty_driver->name_base is doing shift in name to
for example ttyPS3.

register_console() is looping over console_cmdline array and looking for
proper name/index combination which is in our case ttyPS/3.
That's why every instance of driver needs to be registered with proper
combination of name/number (ttyPS/3). Using uport->line is doing
registration with ttyPS/0 which is wrong that's why proper console index
should be used which is in cons->index field.

Also it is visible that recording console should be done based on
information about console not about the port but in most cases numbers are
the same and xilinx_uartps is only one exception now.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/4a877f1c7189a7c45b59a6ebfc3de607e8758949.1567434470.git.michal.simek@xilinx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-04 14:58:05 +02:00
Linus Torvalds
aefcf2f4b5 Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull kernel lockdown mode from James Morris:
 "This is the latest iteration of the kernel lockdown patchset, from
  Matthew Garrett, David Howells and others.

  From the original description:

    This patchset introduces an optional kernel lockdown feature,
    intended to strengthen the boundary between UID 0 and the kernel.
    When enabled, various pieces of kernel functionality are restricted.
    Applications that rely on low-level access to either hardware or the
    kernel may cease working as a result - therefore this should not be
    enabled without appropriate evaluation beforehand.

    The majority of mainstream distributions have been carrying variants
    of this patchset for many years now, so there's value in providing a
    doesn't meet every distribution requirement, but gets us much closer
    to not requiring external patches.

  There are two major changes since this was last proposed for mainline:

   - Separating lockdown from EFI secure boot. Background discussion is
     covered here: https://lwn.net/Articles/751061/

   -  Implementation as an LSM, with a default stackable lockdown LSM
      module. This allows the lockdown feature to be policy-driven,
      rather than encoding an implicit policy within the mechanism.

  The new locked_down LSM hook is provided to allow LSMs to make a
  policy decision around whether kernel functionality that would allow
  tampering with or examining the runtime state of the kernel should be
  permitted.

  The included lockdown LSM provides an implementation with a simple
  policy intended for general purpose use. This policy provides a coarse
  level of granularity, controllable via the kernel command line:

    lockdown={integrity|confidentiality}

  Enable the kernel lockdown feature. If set to integrity, kernel features
  that allow userland to modify the running kernel are disabled. If set to
  confidentiality, kernel features that allow userland to extract
  confidential information from the kernel are also disabled.

  This may also be controlled via /sys/kernel/security/lockdown and
  overriden by kernel configuration.

  New or existing LSMs may implement finer-grained controls of the
  lockdown features. Refer to the lockdown_reason documentation in
  include/linux/security.h for details.

  The lockdown feature has had signficant design feedback and review
  across many subsystems. This code has been in linux-next for some
  weeks, with a few fixes applied along the way.

  Stephen Rothwell noted that commit 9d1f8be5cf42 ("bpf: Restrict bpf
  when kernel lockdown is in confidentiality mode") is missing a
  Signed-off-by from its author. Matthew responded that he is providing
  this under category (c) of the DCO"

* 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (31 commits)
  kexec: Fix file verification on S390
  security: constify some arrays in lockdown LSM
  lockdown: Print current->comm in restriction messages
  efi: Restrict efivar_ssdt_load when the kernel is locked down
  tracefs: Restrict tracefs when the kernel is locked down
  debugfs: Restrict debugfs when the kernel is locked down
  kexec: Allow kexec_file() with appropriate IMA policy when locked down
  lockdown: Lock down perf when in confidentiality mode
  bpf: Restrict bpf when kernel lockdown is in confidentiality mode
  lockdown: Lock down tracing and perf kprobes when in confidentiality mode
  lockdown: Lock down /proc/kcore
  x86/mmiotrace: Lock down the testmmiotrace module
  lockdown: Lock down module params that specify hardware parameters (eg. ioport)
  lockdown: Lock down TIOCSSERIAL
  lockdown: Prohibit PCMCIA CIS storage when the kernel is locked down
  acpi: Disable ACPI table override if the kernel is locked down
  acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down
  ACPI: Limit access to custom_method when the kernel is locked down
  x86/msr: Restrict MSR access when the kernel is locked down
  x86: Lock down IO port access when the kernel is locked down
  ...
2019-09-28 08:14:15 -07:00
David Howells
794edf30ee lockdown: Lock down TIOCSSERIAL
Lock down TIOCSSERIAL as that can be used to change the ioport and irq
settings on a serial port.  This only appears to be an issue for the serial
drivers that use the core serial code.  All other drivers seem to either
ignore attempts to change port/irq or give an error.

Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
2019-08-19 21:54:16 -07:00
Serge Semin
13b18d3590 tty: serial_core: Set port active bit in uart_port_activate
A bug was introduced by commit b3b576461864 ("tty: serial_core: convert
uart_open to use tty_port_open"). It caused a constant warning printed
into the system log regarding the tty and port counter mismatch:

[   21.644197] ttyS ttySx: tty_port_close_start: tty->count = 1 port count = 2

in case if session hangup was detected so the warning is printed starting
from the second open-close iteration.

Particularly the problem was discovered in situation when there is a
serial tty device without hardware back-end being setup. It is considered
by the tty-serial subsystems as a hardware problem with session hang up.
In this case uart_startup() will return a positive value with TTY_IO_ERROR
flag set in corresponding tty_struct instance. The same value will get
passed to be returned from the activate() callback and then being returned
from tty_port_open(). But since in this case tty_port_block_til_ready()
isn't called the TTY_PORT_ACTIVE flag isn't set (while the method had been
called before tty_port_open conversion was introduced and the rest of the
subsystem code expected the bit being set in this case), which prevents the
uart_hangup() method to perform any cleanups including the tty port
counter setting to zero. So the next attempt to open/close the tty device
will discover the counters mismatch.

In order to fix the problem we need to manually set the TTY_PORT_ACTIVE
flag in case if uart_startup() returned a positive value. In this case
the hang up procedure will perform a full set of cleanup actions including
the port ref-counter resetting.

Fixes: b3b576461864 "tty: serial_core: convert uart_open to use tty_port_open"
Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-18 09:52:26 +02:00