This is a followup on 44117a1d ("serial: core: mark port as
initialized after successful IRQ change").
Nikola has been using autoconfig via setserial and reported a crash
similar to what I fixed in the earlier mentioned commit. Here I do the
same fixup for the autoconfig. I wasn't sure that this is the right
approach. Nikola confirmed that it fixes his crash.

Fixes: b3b57646 ("tty: serial_core: convert uart_open to use tty_port_open")
Link: http://lkml.kernel.org/r/20180131072000.GD1853@localhost.localdomainReported-by: NNikola Ciprich <nikola.ciprich@linuxbox.cz>
Tested-by: NNikola Ciprich <nikola.ciprich@linuxbox.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: NNikola Ciprich <nikola.ciprich@linuxbox.cz>
Acked-by: NJohan Hovold <johan@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

setserial changes the IRQ via uart_set_info(). It invokes
uart_shutdown() which free the current used IRQ and clear
TTY_PORT_INITIALIZED. It will then update the IRQ number and invoke
uart_startup() before returning to the caller leaving
TTY_PORT_INITIALIZED cleared.

The next open will crash with
|  list_add double add: new=ffffffff839fcc98, prev=ffffffff839fcc98, next=ffffffff839fcc98.
since the close from the IOCTL won't free the IRQ (and clean the list)
due to the TTY_PORT_INITIALIZED check in uart_shutdown().

There is same pattern in uart_do_autoconfig() and I *think* it also
needs to set TTY_PORT_INITIALIZED there.
Is there a reason why uart_startup() does not set the flag by itself
after the IRQ has been acquired (since it is cleared in uart_shutdown)?
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The pointed string is never modified from within uart_parse_options, so
it should be marked as const in the function prototype.
Signed-off-by: NPaul Cercueil <paul@crapouillou.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When a driver invokes the uart_get_rs485_mode() helper, set the RTS
polarity to active high by default unless the newly introduced
"rs485-rts-active-low" property was specified.

imx contains a line to set the default RTS polarity to active high,
it is now superfluous and hence deleted.

omap-serial historically defaults to active low and supports an
"rs485-rts-active-high" property to inverse the polarity.
Retain that behavior for compatibility.

Cc: Mark Jackson <mpfj@newflow.co.uk>
Cc: Michał Oleszczyk <oleszczyk.m@gmail.com>
Cc: Rafael Gago Castano <rgc@hms.se>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit ef838a81 ("serial: Add common rs485 device tree parsing
function") consolidated retrieval of rs485 OF properties in a common
helper function but did not #ifdef it to CONFIG_OF.  The function is
therefore included on ACPI platforms as well even though it's not used.

On the other hand ACPI platforms with rs485 do exist (e.g. Siemens
IOT2040) and they may leverage _DSD to store rs485 properties.  Likewise,
UART platform devices instantiated from an MFD should be able to specify
rs485 properties.  In fact, the tty subsystem maintainer had asked for
a "generic" function during review of commit ef838a81:
https://marc.info/?l=linux-serial&m=150143441725194&w=4

Thus, instead of constraining the helper to OF platforms, make it
platform-agnostic by converting it to device_property_*() functions
and renaming it accordingly.

In imx.c, move the invocation of uart_get_rs485_mode() from
serial_imx_probe_dt() to serial_imx_probe() so that it also gets called
for non-OF devices.

In omap-serial.c, move its invocation further up within
serial_omap_probe_rs485() so that the RTS polarity can be overridden
with the driver-specific "rs485-rts-active-high" property once we
introduce a generic "rs485-rts-active-low" property.

Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Now that the SPDX tag is in all tty files, that identifies the license
in a specific and legally-defined manner.  So the extra GPL text wording
can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text.  And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Cc: Jiri Slaby <jslaby@suse.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Joachim Eastwood <manabian@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: Pat Gefre <pfg@sgi.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Sylvain Lemieux <slemieux.tyco@gmail.com>
Cc: Carlo Caione <carlo@caione.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: David Brown <david.brown@linaro.org>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Timur Tabi <timur@tabi.org>
Cc: Tony Prisk <linux@prisktech.co.nz>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/tty files files with the correct SPDX license
identifier based on the license text in the file itself.  The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Jiri Slaby <jslaby@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Joachim Eastwood <manabian@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: "Uwe Kleine-König" <kernel@pengutronix.de>
Cc: Pat Gefre <pfg@sgi.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Sylvain Lemieux <slemieux.tyco@gmail.com>
Cc: Carlo Caione <carlo@caione.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: David Brown <david.brown@linaro.org>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Timur Tabi <timur@tabi.org>
Cc: Tony Prisk <linux@prisktech.co.nz>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Jiri Slaby <jslaby@suse.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The final assignment to port is never read, hence it is redundant
and can be removed. Also move the declaration of port to a more
local scope.  Cleans up clang warning:

drivers/tty/serial/serial_core.c:1498:2: warning: Value stored
to 'port' is never read
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Several drivers have the same device tree parsing code. Create
a common helper function for it.

This patch bases on work done by Sascha Hauer.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Previously the rs485 settings weren't considered when setting the RTS
line, so e.g. closing and reopening a port made serial_core to drive
the line as if rs485 was disabled.

This patch fixes those issues.
Signed-off-by: NRafael Gago Castano <rgc@hms.se>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no need to duplicate a flag which IRQ core takes care of.

Replace custom flag by IRQ core API that retrieves its state.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

upf_t is a bitwise defined type and any assignment from different, but
compatible, types makes static analyzer unhappy.

drivers/tty/serial/serial_core.c:793:29: warning: incorrect type in assignment (different base types)
drivers/tty/serial/serial_core.c:793:29:    expected int [signed] flags
drivers/tty/serial/serial_core.c:793:29:    got restricted upf_t [usertype] flags
drivers/tty/serial/serial_core.c:867:19: warning: incorrect type in assignment (different base types)
drivers/tty/serial/serial_core.c:867:19:    expected restricted upf_t [usertype] new_flags
drivers/tty/serial/serial_core.c:867:19:    got int [signed] flags

Enforce corresponding types when upf_t being assigned.

Note, we need __force attribute due to the scope of variable. It's being
used in user space with plain old type while kernel uses bitwise one.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Contrary to what a comment claimed, the ASYNC_SPD flags and custom
divisor can be set by a non-privileged user so rate limit the
deprecation notice as was intended.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Enable serdev support by using the new device-registration helpers.
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

With serdev we might end up with serial ports that have no cdev exported
to userspace, as they are used as the bus interface to other devices. In
that case serial_match_port() won't be able to find a matching tty_dev.

Skip the irq wakeup enabling in that case, as serdev will make sure to
keep the port active, as long as there are devices depending on it.

Fixes: 8ee3fde0 (tty_port: register tty ports with serdev bus)
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since we have port name stored in struct uart_port, we better to use
that one instead of open coding.

This will make it one place source for easier maintenance or
modifications.

While here, replace printk(KERN_INFO ) by pr_info(). It seems last printk()
call in serial_core.c.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Introduce a field to store name of uart_port that can be used to easily
identify UART port instances on a system that has more than one UART
instance. The name is of the form ttyXN(eg. ttyS0, ttyAMA0,..) where N
is number that particular UART instance.
This field will be useful when printing debug info for a particular port
or in register IRQs with unique IRQ name. Port name is populated during
uart_add_one_port().
Signed-off-by: NVignesh R <vigneshr@ti.com>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Coverity complains about uart_state checks in polling functions. And it
is indeed correct. We do something like this:
	struct uart_state *state = drv->state + line;
	if (!state)
		return;

Adding 'line' to drv->state would move the potential NULL pointer to
something near NULL and the check is useless. Even if we checked pure
drv->state, nothing guarantees it is not freed and NULLed after the
check. So if the only user of this interface (kgdboc) needs to assure
something, this is neither the correct thing, nor place to do so.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: kgdb-bugreport@lists.sourceforge.net
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h>

Fix up affected files that include this signal functionality via sched.h.
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.
Requested-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is no need to check port for NULL in uart_port_deref() since we call it
only when port is defined.

There are few places that violate this. Fix them here as well.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit 761ed4a9 ("tty: serial_core: convert uart_close to
use tty_port_close"), the serial console is broken on various systems
and typing "reboot" splats the following on the serial console:

INIT: Sending p[  427.863916] BUG: unable to handle kernel NULL pointer dereference at 00000000000001e0
[  427.885156] IP: [] tty_wakeup+0xc/0x70
[  427.898337] PGD 0 [  427.902051]
[  427.907498] Oops: 0000 [#1] PREEMPT SMP
[  427.917635] Modules linked in: nfsv3 nfs_acl nfs fscache lockd
sunrpc grace edd af_packet cpufreq_conservative cpufreq_userspace
cpufreq_powersave fuse loop md_mod dm_mod joydev hid_generic usbhid
ipmi_ssif ohci_pci ohci_hcd ehci_pci ehci_hcd e1000e ptp firewire_ohci
edac_core pps_core tpm_infineon sp5100_tco firewire_core acpi_cpufreq
serio_raw pcspkr fjes usbcore shpchp edac_mce_amd tpm_tis ipmi_si
tpm_tis_core i2c_piix4 k10temp sg ipmi_msghandler tpm sr_mod button
cdrom kvm_amd kvm irqbypass crc_itu_t ast ttm drm_kms_helper drm
fb_sys_fops sysimgblt sysfillrect syscopyarea i2c_algo_bit scsi_dh_rdac
scsi_dh_alua scsi_dh_emc scsi_dh_hp_sw ata_generic pata_atiixp
[  428.054179] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.0-rc1-1.g73e3f23-default #1
[  428.072868] Hardware name: System manufacturer System Product Name/KGP(M)E-D16, BIOS 0902    12/03/2010
[  428.094755] task: ffffffffa2c0d500 task.stack: ffffffffa2c00000
[  428.109717] RIP: 0010:[]  [] tty_wakeup+0xc/0x70
[  428.128407] RSP: 0018:ffff9a1a5fc03df8  EFLAGS: 00010086
[  428.142184] RAX: ffff9a1857258000 RBX: ffffffffa3050ea0 RCX: 0000000000000000
[  428.159649] RDX: 000000000000001b RSI: 0000000000000000 RDI: 0000000000000000
[  428.177109] RBP: ffff9a1a5fc03e08 R08: 0000000000000000 R09: 0000000000000000
[  428.194547] R10: 0000000000021c77 R11: 0000000000000000 R12: ffff9a1857258000
[  428.212002] R13: 0000000000000000 R14: 0000000000000020 R15: 0000000000000020
[  428.229481] FS:  0000000000000000(0000) GS:ffff9a1a5fc00000(0000) knlGS:0000000000000000
[  428.248938] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  428.263726] CR2: 00000000000001e0 CR3: 0000000390c06000 CR4: 00000000000006f0
[  428.281331] Stack:
[  428.288696]  ffffffffa3050ea0 ffff9a1857258000 ffff9a1a5fc03e18 ffffffffa24e0ab1
[  428.307064]  ffff9a1a5fc03e40 ffffffffa24e8865 ffffffffa3050ea0 00000000000000c2
[  428.325456]  0000000000000046 ffff9a1a5fc03e78 ffffffffa24e8a5f ffffffffa3050ea0
[  428.343905] Call Trace:
[  428.352319]   [  428.356216]  [] uart_write_wakeup+0x21/0x30

The problem is for console ports, the serial port is not shutdown and
interrupts may fire after the struct tty is gone. Simply calling the
tty_port helper tty_port_tty_wakeup instead of tty_wakeup directly will
ensure there is a valid struct tty.

Fixes: 761ed4a9 ("tty: serial_core: convert uart_close to use tty_port_close")
Reported-by: NBorislav Petkov <bp@alien8.de>
Reported-by: NMike Galbraith <mgalbraith@suse.de>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-serial@vger.kernel.org
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The port->console flag is always false, as uart_console() is called
before the serial console has been registered.

Hence for a serial port used as the console, uart_tty_port_shutdown()
will still be called when userspace closes the port, powering it down.
This may lead to a system lock up when the serial console driver writes
to the serial port's registers.

To fix this, move the setting of port->console after the call to
uart_configure_port(), which registers the serial console.

Fixes: 761ed4a9 ("tty: serial_core: convert uart_close to use tty_port_close")
Reported-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NRob Herring <robh@kernel.org>
Tested-by: NMugunthan V N <mugunthanvnm@ti.com>
Tested-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
[robh: rebased on tty-linus]
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 761ed4a9 ('tty: serial_core: convert uart_close to use
tty_port_close') started setting the ttyport console flag for serial
drivers. This is causing crashes, hangs, or garbage output on several
platforms because the serial shutdown is skipped and IRQs are left
enabled.

Partially revert commit 761ed4a9 and drop reporting UART tty_ports
as a console leaving the console handling to the serial_core as it was
before.

Fixes: 761ed4a9 ("tty: serial_core: convert uart_close to use tty_port_close")
Reported-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reported-by: NMike Galbraith <umgwanakikbuti@gmail.com>
Reported-by: NMugunthan V N <mugunthanvnm@ti.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The commit 761ed4a9 ("tty: serial_core: convert uart_close to use
tty_port_close") refactored uart_close() to use tty_port_close().  At the same
time it introduced a potential NULL pointer dereference. Rearrange the code to
avoid kernel crash.

Fixes: 761ed4a9 ("tty: serial_core: convert uart_close to use tty_port_close")
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Guenter Roeck reported a regression caused by commit "serial: earlycon:
Extend earlycon command line option to support 64-bit addresses":

console= and earlycon= options have the following format:
...,<addr>,<options>

Historically used here simple_strtoul() had no problems with comma, but the
new and recommended kstrtoull() requires null-terminated string and returns
-EINVAL in case there are "options" at the end. There is no recommended to
use function currently that will support it, so stick to obsolete
simple_strtoull() variant.
Signed-off-by: NAlexander Sverdlin <alexander.sverdlin@nokia.com>
Reported-by: NGuenter Roeck <linux@roeck-us.net>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Tested-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

earlycon implementation used "unsigned long" internally, but there are systems
(ARM with LPAE) where sizeof(unsigned long) == 4 and uart is mapped beyond 4GiB
address range.

Switch to resource_size_t internally and replace obsoleted simple_strtoul() with
kstrtoull().
Signed-off-by: NAlexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

tty_port_close handles much of the common parts of tty close. Convert
uart_close to use it and move the serial_core specific parts into
tty_port.shutdown function. This will be needed to use tty_port functions
directly from in kernel clients.

This change causes ops->stop_rx() to be called after uart_wait_until_sent()
is called which I think should be fine. Otherwise, the sequence of the
close should be the same.

Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: NRob Herring <robh@kernel.org>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

tty_port_open handles much of the common parts of tty opening. Convert
uart_open to use it and move the serial_core specific parts into
tty_port.activate function. This will be needed to use tty_port functions
directly from in kernel clients.

The tricky part is uart_port_startup can return positive values to allow
setserial to configure the port. We now return the positive value to
tty_port_open so that the tty is not marked as initialized and then set the
return value in uart_open to 0.

Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: NRob Herring <robh@kernel.org>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Doing the following UART bind/unbind sequence on a i.mx platform causes
a kernel crash due to NULL pointer dereference:

echo  21f4000.serial > /sys/bus/platform/drivers/imx-uart/bind
echo  21f4000.serial > /sys/bus/platform/drivers/imx-uart/unbind

Fix this problem by adding NULL checks prior to calling release/request_port
ops.
Reported-by: NFugang Duan <fugang.duan@nxp.com>
Signed-off-by: NFabio Estevam <fabio.estevam@nxp.com>
Tested-by: NFugang Duan <fugang.duan@nxp.com>
Acked-by: NFugang Duan <fugang.duan@nxp.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 4047b371 ("serial: core: Prevent unsafe uart port access,
part 1") added lockdep assertion for port mutex but fails to check
if debug_locks has disabled lockdep (so lock state is no longer
reliable).

Use lockdep_assert_held() instead, which properly checks lockdep
state as well.
Reported-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

For tty operations which may expect uart port to have been removed
but still have other necessary work to accomplish, check for NULL
uart port; specifically uart_close(), uart_hangup() and sub-functions
(uart_shutdown() and uart_port_shutdown()).
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

For serial core operations not already excluded by holding port->mutex,
use reference counting to protect deferencing the state->uart_port.

Introduce helper functions, uart_port_ref() and uart_port_deref(), to
wrap uart_port access, and helper macros, uart_port_lock() and
uart_port_unlock(), to wrap combination uart_port access with uart
port lock sections.

Port removal in uart_remove_one_port() waits for reference count to
drop to zero before detaching the uart port from struct uart_state.

For functions only reading the tx circular buffer indexes (where the
uart port lock is claimed to prevent concurrent users), a NULL uart
port is simply ignored and the operation completes normally.

For functions change the tx circular buffer indexes (where the uart
port lock is claimed to prevent concurrent users), the operation is
aborted if the uart port is NULL (ie., has been detached).
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

uart_remove_one_port() may race with every serial core operation
requiring a valid dereference of state->uart_port. In particular,
uart_remove_one_port() may unlink the uart port concurrently with
any serial core operation that may dereference same.

Ensure safe dereference for those operations that already claim
the port->mutex, and extend that guarantee for trivial cases,
such as the ioctl handlers. Introduce the uart_port_check() helper
which asserts port->mutex is held (only when lockdep is on).

For ioctls, return -EIO as if the port has been hung up (since it has).
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Prepare uart_poll_init() to safely dereference uart port; expand the
port mutex section to guarantee uart port remains valid until
uart_poll_init() completes.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace ASYNC_INITIALIZED bit in the tty_port::flags field with
TTY_PORT_INITIALIZED bit in the tty_port::iflags field. Introduce helpers
tty_port_set_initialized() and tty_port_initialized() to abstract
atomic bit ops.

Note: the transforms for test_and_set_bit() and test_and_clear_bit()
are unnecessary as the state transitions are already mutually exclusive;
the tty lock prevents concurrent open/close/hangup.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace ASYNC_SUSPENDED bit in the tty_port::flags field with
TTY_PORT_SUSPENDED bit in the tty_port::iflags field. Introduce helpers
tty_port_set_suspended() and tty_port_suspended() to abstract
atomic bit ops.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace ASYNC_NORMAL_ACTIVE bit in the tty_port::flags field with
TTY_PORT_ACTIVE bit in the tty_port::iflags field. Introduce helpers
tty_port_set_active() and tty_port_active() to abstract atomic bit ops.

Extract state changes from port lock sections, as this usage is
broken and confused; the state transitions are protected by the
tty lock (which mutually excludes parallel open/close/hangup),
and no user tests the active state while holding the port lock.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Abstract TTY_THROTTLED bit tests with tty_throttled().
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Abstract TTY_IO_ERROR status test treewide with tty_io_error().
NB: tty->flags uses atomic bit ops; replace non-atomic bit test
with test_bit().
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>