The commit 761ed4a945 ("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: 761ed4a945 ("tty: serial_core: convert uart_close to use tty_port_close")
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg 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: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg 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: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Greg 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: Rob Herring <robh@kernel.org>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg 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: Rob Herring <robh@kernel.org>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4047b37122 ("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: Tony Lindgren <tony@atomide.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Greg 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: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg 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: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg 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: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg 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: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg 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: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg 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: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg 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: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Abstract TTY_THROTTLED bit tests with tty_throttled().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg 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: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, when tring to set up a serial console with a higher
baud rate, it would fallback to 921600.
Tested-by: Jianqun Xu <jay.xu@rock-chips.com>
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The tty core no longer provides nor uses ASYNC_CLOSING; remove from
tty_port_close_start() and tty_port_close_end() as well as tty drivers
which open-code these state changes. Unfortunately, even though the
bit is masked from userspace, its inclusion in a uapi header precludes
removing the macro.
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: linux-cris-kernel@axis.com
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When throttling, time is of the essence; try RTS signalling before
soft flow control, which will take longer.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
void * promotes to any pointer type; remove type cast.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If aborting uart_open() unsuccessfully, retval is non-zero, so the
existing fall-through exit is equivalent.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The uart port may have already been removed by uart_remove_one_port();
use equivalent tty->index (which is always valid in these contexts)
instead.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
do_uart_get_info() has a single caller: uart_get_info().
Manually inline do_uart_get_info().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Expressions of the form "tty->termios.c_*flag & FLAG"
are more clearly expressed with the termios flags macros,
I_FLAG(), C_FLAG(), O_FLAG(), and L_FLAG().
Convert treewide.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, 8-bit (MMIO) and 32-bit (MMIO32) register interfaces are
supported for the 8250 console, but the 16-bit (MMIO16) is not.
The 8250 UART device on my board is connected to a 16-bit bus and
my main motivation is to use earlycon with it.
(Refer to arch/arm/boot/dts/uniphier-support-card.dtsi)
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
With the removal of tty_wait_until_sent_from_close(), tty drivers
no longer wait during open for parallel closes to complete (instead,
the tty core waits before calling the driver open() method). Thus,
the close_wait waitqueue is no longer used for waiting.
Remove struct tty_port::close_wait.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There are three natural ways in which devices may be wired to the system:
little endian (device receives correctly ordered bits of a word written
by little-endian CPU to its register, but big-endian CPU needs to swap
bytes of a word before writing it), big endian (same, but with big-endian
CPU in more favourable position) and native endian (CPU of either
endianness may do word-sized I/O without need for byteswapping).
Adding an option for native endianness allows using single kernel command
line for boards with native-endian serial ports on bi-endian
architectures. This goes in parallel with 'native-endian' DTS attribute.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial core does not use tty_port_open() or tty_port_close(); serial
core defines and extends it's own tty open() and close() methods
(uart_open() and uart_close(), respectively).
Remove the tty_port activate() and shutdown() initializations, and
the uart_port_activate() function, which is never called.
NB: uart_port_shutdown() is used by uart_close() => uart_shutdown()
call chain (but not via the tty_port methods).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
uart_close() runs in non-atomic context only; use
spin_lock/unlock_irq instead of saving the interrupt state (which
== on).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
While closing, new rx data may be received after the input buffers
have been flushed but before stop_rx() halts receiving [1]. The
new data might not be processed by flush_to_ldisc() until after
uart_shutdown() and normal input processing is re-enabled (ie.,
tty->closing = 0). The race is outlined below:
CPU 0 | CPU 1
|
uart_close() |
tty_port_close_start() |
tty->closing = 1 |
tty_ldisc_flush() |
| => IRQ
| while (LSR & data ready)
| uart_insert_char()
| tty_flip_buffer_push()
| <= EOI
stop_rx() | .
uart_shutdown() | .
free xmit.buf | .
tty_port_tty_set(NULL) | .
tty->closing = 0 | .
| flush_to_ldisc()
| n_tty_receive_buf_common()
| __receive_buf()
| ...
| commit_echoes()
| uart_flush_chars()
| __uart_start()
| ** OOPS on port.tty deref **
tty_ldisc_flush() |
Input processing must be prevented from echoing (tty->closing = 1)
until _after_ the input buffers have been flushed again at the end
of uart_close().
[1] In fact, some input may actually be buffered _after_ stop_rx()
since the rx interrupt may have already triggered but not yet been
handled when stop_rx() disables rx interrupts.
Fixes: 2e75891083 ("serial: core: Flush ldisc after dropping port
mutex in uart_close()")
Reported-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Align with coding guidelines:
Replaced a chain of "else if" by a switch case.
Signed-off-by: Joakim Nordell <joakim.nordell@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Support command line parameters of the form:
earlycon=<name>,io|mmio|mmio32|mmio32be,<addr>,<options>
This commit seem to be needed even after commit:
serial: 8250: Add support for big-endian MMIO accesses
c627f2ceb6
Signed-off-by: Noam Camus <noamc@ezchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_name no longer uses the buf parameter, so remove it along with all
the 64 byte stack buffers that used to be passed in.
Mostly generated by the coccinelle script
@depends on patch@
identifier buf;
constant C;
expression tty;
@@
- char buf[C];
<+...
- tty_name(tty, buf)
+ tty_name(tty)
...+>
allmodconfig compiles, so I'm fairly confident the stack buffers
weren't used for other purposes as well.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
'/**' is required to start a kernel-doc comment block.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
UART drivers that share ttyS namespace cannot trivially compute the
ttyS index from the port->line value since the minor_start may be
offset from minor 64. Further, to do so requires a pointer to the
uart driver since there is no back pointer from uart_port to
uart_driver.
Rather than have UART drivers computing the minor value by themselves,
encapsulate within the serial core at port registration time.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Prepare to support console-defined matching; refactor the command
line parameter string processing from parse_options() into a
new core function, uart_parse_earlycon(), which decodes command line
parameters of the form:
earlycon=<name>,io|mmio|mmio32,<addr>,<options>
console=<name>,io|mmio|mmio32,<addr>,<options>
earlycon=<name>,0x<addr>,<options>
console=<name>,0x<addr>,<options>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use helper functions to access current->state.
Direct assignments are prone to races and therefore buggy.
Thanks to Peter Zijlstra for the exact definition of the problem.
Suggested-By: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hw-assisted flow control support was added to the serial core
in v3.8 with commits,
dba05832cb ("SERIAL: core: add hardware assisted h/w flow control support")
2cbacafd7a ("SERIAL: core: add hardware assisted s/w flow control support")
9aba8d5b01 ("SERIAL: core: add throttle/unthrottle callbacks for hardware
assisted flow control")
Since then, additional requirements for serial core support have arisen.
Specifically,
1. Separate tx and rx flow control settings for UARTs which only support
tx flow control (ie., autoCTS).
2. Disable sw-assisted CTS flow control in autoCTS mode
3. Support for RTS flow control by serial core and userspace in autoRTS mode
Distinguish mode from capability; introduce UPSTAT_AUTORTS, UPSTAT_AUTOCTS
and UPSTAT_AUTOXOFF which, when set by the uart driver, enable serial core
support for hw-assisted rx, hw-assisted tx and hw-assisted in-band/IXOFF
rx flow control, respectively. [Note: hw-assisted in-band/IXON tx flow
control does not require serial core support/intervention and can be
enabled by the uart driver when required.]
These modes must be set/reset in the driver's set_termios() method, based
on termios settings, and thus can be safely queried in any context in which
one of the port lock, port mutex or termios rwsem are held. Set these modes
in the 2 in-tree drivers, omap-serial and 8250_omap, which currently
use UPF_HARD_FLOW/UPF_SOFT_FLOW support.
Retain UPF_HARD_FLOW and UPF_SOFT_FLOW as capabilities; re-define
UPF_HARD_FLOW as both UPF_AUTO_RTS and UPF_AUTO_CTS to allow for distinct
and separate rx and tx flow control capabilities.
Disable sw-assisted CTS flow control when UPSTAT_AUTOCTS is enabled.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When the uart port being suspended is a console and consoles are
not suspending (kernel command line contains no_console_suspend),
then no action is performed for that port, and the function can
return early.
If the function has not returned early, then one of the conditions
is not true, so the expression
(console_suspend_enabled || !uart_console(uport))
must be true and can be eliminated.
Similarly, the expression
(console_suspend_enabled && uart_console(uport))
simplifies to just uart_console(uport).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is a partial revert of 2f2dafe (serial: serial_core.c: printk
replacement) which gets us booting again. The real problem seems to be
the _emit path in early boot. However, until we can root cause it, we
need at least to get boot working.
Fixes: 2f2dafe77d
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since most drivers interpret UPIO_MEM32 to mean "little-endian" and use
readl/writel to access the registers, add a parallel UPIO_MEM32BE to
request the use of big-endian MMIO accessors (ioread32be/iowrite32be).
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce an homogeneous lock system between setting and using the rs485
data of the uart_port.
This patch should not be split into multiple ones in order to avoid
leaving the tree in an unstable state.
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Suggested-by: Alan Cox <alan@linux.intel.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Once there is no more handlers for TIOC[GS]RS485 there is no need to
call the driver specific ioctl when the generic implementation is
missing.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The following drivers: 8250_core, atmel_serial, max310x, mcf, omap-serial
and sci16is7xx implement code to handle RS485 ioctls.
In order to avoid code duplication, we implement a simple ioctl handler
on the serial_core layer.
This handler can be used by all the other drivers instead of duplicating
code.
Until this is the only RS485 ioctl handler, it will try first the
rs485_config callback and if it is not present it will call the driver
specific ioctl.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
UART drivers which enable modem status interrupts when switching
to N_PPS line discipline need to determine if modem status
interrupts should be disabled when switching from N_PPS.
Specifically, the set_ldisc() notification needs to evaluate
UART_ENABLE_MS() which requires termios->c_cflag.
Convert in-tree UART drivers to new interface.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Three UART drivers (8250, atmel & amba-pl010) enable modem status
interrupts if the line discipline is changed to N_PPS. However,
the uart port flags may only be safely modified while holding the
port mutex.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Andy Shevchenko