Commit Graph

47 Commits

Author SHA1 Message Date
Al Viro
e21120383f move compat handling of tty ioctls to tty_compat_ioctl()
ioctls that are
	* callable only via tty_ioctl()
	* not driver-specific
	* not demand data structure conversions
	* either always need passing arg as is or always demand compat_ptr()
get intercepted in tty_compat_ioctl() from the very beginning and
redirecter to tty_ioctl().  As the result, their entries in fs/compat_ioctl.c
(some of those had been missing, BTW) got removed, as well as
n_tty_compat_ioctl_helper() (now it's never called with any cmd it would accept).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-09-14 11:12:17 -04:00
Johan Hovold
7b0c6b38c4 tty: add missing const to termios hw-change helper
Add missing const qualifiers to the parameters of the termios hw-change
helper, which is used by a few USB serial drivers. This specifically
allows the pl2303 driver to use const arguments in one of its helper as
well.

Cc: Jiri Slaby <jslaby@suse.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
2018-05-22 10:08:05 +02:00
Greg Kroah-Hartman
e3b3d0f549 tty: add SPDX identifiers to all remaining files in drivers/tty/
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-08 13:08:12 +01:00
Nicolas Pitre
fff0a2ca3a tty: move baudrate handling code to a file of its own
To allow reuse without the rest of the tty_ioctl code.
No logical changes from this patch.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-18 18:01:52 +02:00
Ingo Molnar
174cd4b1e5 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: Linus 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: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:32 +01:00
Linus Torvalds
7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
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: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 11:46:01 -08:00
Peter Hurley
97ef38b821 tty: Replace TTY_THROTTLED bit tests with tty_throttled()
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>
2016-04-30 09:26:55 -07:00
Peter Hurley
9db276f8f0 tty: Use termios c_*flag macros
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>
2016-01-28 14:13:44 -08:00
Peter Hurley
d435cefe9c tty: Remove __func__ from tty_debug() macro
Now that tty_debug() macro uses pr_debug(), the function name can
be printed when using dynamic debug; printing the function name within
the format string is redundant.

Remove the __func__ parameter and print specifier from the format string.
Add context to messages for when the function name is not printed by
dynamic debug, or when dynamic debug is not enabled.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-13 19:59:48 -08:00
Peter Hurley
89222e6266 tty: core: Prefer pr_* to printk(*)
Convert remaining printk() use to pr_*() when tty is unknown or
unsafe to use.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-13 19:59:48 -08:00
Peter Hurley
f658dca950 tty: Remove unset_locked_termios() error message
With the refactor of 'locked' from parameter to local,
it's now obvious locked cannot be NULL. Remove entire conditional.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-13 19:59:48 -08:00
Peter Hurley
d97ba9cdae tty: core: Refactor parameters for unset_locked_termios() helper
Add tty as parameter to unset_locked_termios() and extract former
parameters, termios and locked, as locals.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-13 19:59:48 -08:00
Peter Hurley
ee0c1a65cf tty: Fix tty_send_xchar() lock order inversion
The correct lock order is atomic_write_lock => termios_rwsem, as
established by tty_write() => n_tty_write().

Fixes: c274f6ef1c ("tty: Hold termios_rwsem for tcflow(TCIxxx)")
Reported-and-Tested-by: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org> # v3.18+
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-11-20 16:19:54 -08:00
Peter Hurley
ff8339dc16 tty: Replace inline #ifdef TTY_DEBUG_WAIT_UNTIL_SENT
Add tty_debug_wait_until_sent() macro which uses tty_debug() to print
the debug message; remove inlined #ifdef.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:37:31 -07:00
Rasmus Villemoes
429b474990 tty: remove buf parameter from tty_name()
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>
2015-05-06 22:26:57 +02:00
Frederic Danis
b00f5c2dc0 tty: Re-add external interface for tty_set_termios()
This is needed by Bluetooth hci_uart module to be able to change speed
of Bluetooth controller and local UART.

Signed-off-by: Frederic Danis <frederic.danis@linux.intel.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-04-28 14:26:20 +02:00
Johan Hovold
c37bc682e3 TTY: fix tty_wait_until_sent maximum timeout
Currently tty_wait_until_sent may take up to twice as long as the
requested timeout while waiting for driver and hardware buffers to
drain.

Fix this by taking the remaining number of jiffies after waiting for
driver buffers to drain into account so that the timeout actually
becomes a maximum timeout as it is documented to be.

Note that this specifically implies tighter timings when closing a port
as a consequence of actually honouring the port closing-wait setting
for drivers relying on tty_wait_until_sent_from_close (e.g. via
tty_port_close_start).

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-07 03:44:15 +01:00
Johan Hovold
79fbf4a550 TTY: fix tty_wait_until_sent on 64-bit machines
Fix overflow bug in tty_wait_until_sent on 64-bit machines, where an
infinite timeout (0) would be passed to the underlying tty-driver's
wait_until_sent-operation as a negative timeout (-1), causing it to
return immediately.

This manifests itself for example as tcdrain() returning immediately,
drivers not honouring the drain flags when setting terminal attributes,
or even dropped data on close as a requested infinite closing-wait
timeout would be ignored.

The first symptom  was reported by Asier LLANO who noted that tcdrain()
returned prematurely when using the ftdi_sio usb-serial driver.

Fix this by passing 0 rather than MAX_SCHEDULE_TIMEOUT (LONG_MAX) to the
underlying tty driver.

Note that the serial-core wait_until_sent-implementation is not affected
by this bug due to a lucky chance (comparison to an unsigned maximum
timeout), and neither is the cyclades one that had an explicit check for
negative timeouts, but all other tty drivers appear to be affected.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>	# v2.6.12
Reported-by: ZIV-Asier Llano Palacios <asier.llano@cgglobal.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-07 03:44:14 +01:00
Peter Hurley
632f32e210 tty: Remove external interface for tty_set_termios()
tty_set_termios() is an internal helper intended for file scope use.

UART drivers which are capable of driving the RTS pin must
properly handle the tiocmset() method, regardless of termios settings.
A failure to do so is a UART driver bug and should be fixed there.
Do not use this interface to workaround UART driver bugs.

Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: <linux-bluetooth@vger.kernel.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-02-02 10:11:28 -08:00
Peter Hurley
c961bfb174 tty: Call methods in modern style
The use of older function ptr calling style, (*fn)(), makes static
analysis more error-prone; replace with modern fn() style.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 20:18:30 -08:00
Peter Hurley
dbfcd851a9 tty: Move pty-specific set_termios() handling to pty driver
Packet mode is unique to the pty driver; move the packet mode state
change code from the generic tty ioctl handler to the pty driver.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 16:34:36 -08:00
Peter Hurley
6460fbbf47 tty: WARN for attempted set_termios() of pty master
The pty master's termios should never be set; currently, all code
paths which call the driver's set_termios() method ensure that the
pty slave's termios is being set.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 16:34:36 -08:00
Peter Hurley
c274f6ef1c tty: Hold termios_rwsem for tcflow(TCIxxx)
While transmitting a START/STOP char for tcflow(TCION/TCIOFF), prevent
a termios change. Otherwise, a garbage in-band flow control char
may be sent, if the termios change overlaps the transmission setup.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:19:36 -07:00
Peter Hurley
136d5258b2 tty: Move and rename send_prio_char() as tty_send_xchar()
Relocate the file-scope function, send_prio_char(), as a global
helper tty_send_xchar(). Remove the global declarations for
tty_write_lock()/tty_write_unlock(), as these are file-scope only now.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:19:35 -07:00
Peter Hurley
c545b66c69 tty: Serialize tcflow() with other tty flow control changes
Use newly-introduced tty->flow_lock to serialize updates to
tty->flow_stopped (via tcflow()) and with concurrent tty flow
control changes from other sources.

Merge the storage for ->stopped and ->flow_stopped, now that both
flags are serialized by ->flow_lock.

The padding bits are necessary to force the compiler to allocate the
type specified; otherwise, gcc will ignore the type specifier and
allocate the minimum number of bytes necessary to store the bitfield.
In turn, this would allow Alpha EV4 and EV5 cpus to corrupt adjacent
byte storage because those cpus use RMW to store byte and short data.

gcc versions < 4.7.2 will also corrupt storage adjacent to bitfields
smaller than unsigned long on ia64, ppc64, hppa64 and sparc64, thus
requiring more than unsigned int storage (which would otherwise be
sufficient to workaround the Alpha non-atomic byte/short storage problem).

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:19:35 -07:00
Matthias Brugger
a1d51aa221 tty: fix typo in comment of tty_termios_encode_baud_rate
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-08 15:32:05 -07:00
Peter Hurley
5cec7bf699 tty: Fix SIGTTOU not sent with tcflush()
Commit 'e7f3880cd9b98c5bf9391ae7acdec82b75403776'
  tty: Fix recursive deadlock in tty_perform_flush()
introduced a regression where tcflush() does not generate
SIGTTOU for background process groups.

Make sure ioctl(TCFLSH) calls tty_check_change() when
invoked from the line discipline.

Cc: stable@vger.kernel.org # v3.10+
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-09-25 17:52:17 -07:00
Peter Hurley
d8c1f929aa tty: Only guarantee termios read safety for throttle/unthrottle
No tty driver modifies termios during throttle() or unthrottle().
Therefore, only read safety is required.

However, tty_throttle_safe and tty_unthrottle_safe must still be
mutually exclusive; introduce throttle_mutex for that purpose.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:02 -07:00
Peter Hurley
6a1c0680cf tty: Convert termios_mutex to termios_rwsem
termios is commonly accessed unsafely (especially by N_TTY)
because the existing mutex forces exclusive access.
Convert existing usage.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-23 16:43:01 -07:00
Peter Hurley
579a00a5c2 tty: Fix unsafe bit ops in tty_throttle_safe/unthrottle_safe
tty->flags needs to be atomically modified.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-04-15 11:08:12 -07:00
Peter Hurley
e7f3880cd9 tty: Fix recursive deadlock in tty_perform_flush()
tty_perform_flush() can deadlock when called while holding
a line discipline reference. By definition, all ldisc drivers
hold a ldisc reference, so calls originating from ldisc drivers
must not block for a ldisc reference.

The deadlock can occur when:
  CPU 0                    |  CPU 1
                           |
tty_ldisc_ref(tty)         |
....                       | <line discipline halted>
tty_ldisc_ref_wait(tty)    |
                           |

CPU 0 cannot progess because it cannot obtain an ldisc reference
with the line discipline has been halted (thus no new references
are granted).
CPU 1 cannot progress because an outstanding ldisc reference
has not been released.

An in-tree call-tree audit of tty_perform_flush() [1] shows 5
ldisc drivers calling tty_perform_flush() indirectly via
n_tty_ioctl_helper() and 2 ldisc drivers calling directly.
A single tty driver safely uses the function.

[1]
Recursive usage:

/* These functions are line discipline ioctls and thus
 * recursive wrt line discipline references */

tty_perform_flush() - ./drivers/tty/tty_ioctl.c
    n_tty_ioctl_helper()
        hci_uart_tty_ioctl(default) - drivers/bluetooth/hci_ldisc.c (N_HCI)
        n_hdlc_tty_ioctl(default) - drivers/tty/n_hdlc.c (N_HDLC)
        gsmld_ioctl(default) - drivers/tty/n_gsm.c (N_GSM0710)
        n_tty_ioctl(default) - drivers/tty/n_tty.c (N_TTY)
        gigaset_tty_ioctl(default) - drivers/isdn/gigaset/ser-gigaset.c (N_GIGASET_M101)
    ppp_synctty_ioctl(TCFLSH) - drivers/net/ppp/pps_synctty.c
    ppp_asynctty_ioctl(TCFLSH) - drivers/net/ppp/ppp_async.c

Non-recursive use:

tty_perform_flush() - drivers/tty/tty_ioctl.c
    ipw_ioctl(TCFLSH) - drivers/tty/ipwireless/tty.c
       /* This function is a tty i/o ioctl method, which
        * is invoked by tty_ioctl() */

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:52:24 -07:00
Jiri Slaby
6865ff222c TTY: do not warn about setting speed via SPD_*
The warning is there since 2.1.69 and we have not seen anybody
reporting it in the past decade. Remove the warning now.

tty_get_baud_rate can now be inline. This gives us one less
EXPORT_SYMBOL.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:19:05 -07:00
Peter Hurley
70bc126471 tty: Add safe tty throttle/unthrottle functions
The tty driver can become stuck throttled due to race conditions
between throttle and unthrottle, when the decision to throttle
or unthrottle is conditional. The following example helps to
illustrate the race:

  CPU 0                        |  CPU 1
                               |
if (condition A)               |
                               | <processing such that A not true>
                               | if (!condition A)
                               |     unthrottle()
    throttle()                 |
                               |

Note the converse is also possible; ie.,

  CPU 0                        |  CPU 1
                               |
                               | if (!condition A)
<processing such that A true>  |
if (condition A)               |
    throttle()                 |
                               |     unthrottle()
                               |

Add new throttle/unthrottle functions based on the familiar model
of task state and schedule/wake. For example,

    while (1) {
        tty_set_flow_change(tty, TTY_THROTTLE_SAFE);
        if (!condition)
            break;
        if (!tty_throttle_safe(tty))
            break;
    }
    __tty_set_flow_change(tty, 0);

In this example, if an unthrottle occurs after the condition is
evaluated but before tty_throttle_safe(), then tty_throttle_safe()
will return non-zero, looping and forcing the re-evaluation of
condition.

Reported-by: Vincent Pillet <vincentx.pillet@intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:11:59 -07:00
Oleg Nesterov
183d95cdd8 tty: set_termios/set_termiox should not return -EINTR
See https://bugzilla.redhat.com/show_bug.cgi?id=904907
read command causes bash to abort with double free or corruption (out).

A simple test-case from Roman:

	// Compile the reproducer and send sigchld ti that process.
	// EINTR occurs even if SA_RESTART flag is set.

	void handler(int sig)
	{
	}

	main()
	{
	  struct sigaction act;
	  act.sa_handler = handler;
	  act.sa_flags = SA_RESTART;
	  sigaction (SIGCHLD, &act, 0);
	  struct termio ttp;
	  ioctl(0, TCGETA, &ttp);
	  while(1)
	  {
	    if (ioctl(0, TCSETAW, ttp) < 0)
	      {
		if (errno == EINTR)
		{
		  fprintf(stderr, "BUG!"); return(1);
		}
	      }
	  }
	}

Change set_termios/set_termiox to return -ERESTARTSYS to fix this
particular problem.

I didn't dare to change other EINTR's in drivers/tty/, but they look
equally wrong.

Reported-by: Roman Rakus <rrakus@redhat.com>
Reported-by: Lingzhu Xiang <lxiang@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-02-04 15:02:14 -08:00
Ilya Zykov
a1bf958442 tty: Add driver unthrottle in ioctl(...,TCFLSH,..).
Regression 'tty: fix "IRQ45: nobody cared"'
Regression commit 7b292b4bf9

  Function reset_buffer_flags() also invoked during the ioctl(...,TCFLSH,..).
At the time of request we can have full buffers and throttled driver too.
If we don't unthrottle driver, we can get forever throttled driver, because,
after request, we will have empty buffers and throttled driver and
there is no place to unthrottle driver.
It simple reproduce with "pty" pair then one side sleep on tty->write_wait,
and other side do ioctl(...,TCFLSH,..). Then there is no place to do writers wake up.

Signed-off-by: Ilya Zykov <ilya@ilyx.ru>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-18 16:07:34 -08:00
Cyrill Gorcunov
06026d911c tty: pty - Move TIOCPKT handling into pty.c
Since this ioctl is for pty devices only move it to pty.c.

v2:
 - drop PTY_TYPE_MASTER test since it's master peer
   ioctl anyway (by jslaby@)

Suggested-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Pavel Emelyanov <xemul@parallels.com>
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-10-25 12:07:18 -07:00
Alan Cox
9833facf90 tty: Fix up PPC fallout from the termios move
This fixes up the problem Stephen Rothwell reported when trying to merge -next

Signed-off-by: Alan Cox <alan@linux.intel.com>
Reported-by: Stephen Rothwell <sfr@cab.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-17 09:10:55 -07:00
Alan Cox
adc8d746ca tty: move the termios object into the tty
This will let us sort out a whole pile of tty related races. The
alternative would be to keep points and refcount the termios objects.
However
1. They are tiny anyway
2. Many devices don't use the stored copies
3. We can remove a pty special case

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-16 13:00:41 -07:00
David Howells
9ffc93f203 Remove all #inclusions of asm/system.h
Remove all #inclusions of asm/system.h preparatory to splitting and killing
it.  Performed with the following command:

perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`

Signed-off-by: David Howells <dhowells@redhat.com>
2012-03-28 18:30:03 +01:00
Thomas Meyer
8193c42906 tty: Support compat_ioctl get/set termios_locked
When running a Fedora 15 (x86) on an x86_64 kernel, in the boot process
plymouthd complains about those two missing ioctls:
[    2.581783] ioctl32(plymouthd:186): Unknown cmd fd(10) cmd(00005457){t:'T';sz:0} arg(ffb6a5d0) on /dev/tty1
[    2.581803] ioctl32(plymouthd:186): Unknown cmd fd(10) cmd(00005456){t:'T';sz:0} arg(ffb6a680) on /dev/tty1

both ioctl functions work on the 'struct termios' resp. 'struct termios2',
which has the same size (36 bytes resp. 44 bytes) on x86 and x86_64,
so it's just a matter of converting the pointer from userland.

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-10-18 14:17:11 -07:00
Linus Torvalds
99dff58562 Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6
* 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6: (48 commits)
  serial: 8250_pci: add support for Cronyx Omega PCI multiserial board.
  tty/serial: Fix break handling for PORT_TEGRA
  tty/serial: Add explicit PORT_TEGRA type
  n_tracerouter and n_tracesink ldisc additions.
  Intel PTI implementaiton of MIPI 1149.7.
  Kernel documentation for the PTI feature.
  export kernel call get_task_comm().
  tty: Remove to support serial for S5P6442
  pch_phub: Support new device ML7223
  8250_pci: Add support for the Digi/IBM PCIe 2-port Adapter
  ASoC: Update cx20442 for TTY API change
  pch_uart: Support new device ML7223 IOH
  parport: Use request_muxed_region for IT87 probe and lock
  tty/serial: add support for Xilinx PS UART
  n_gsm: Use print_hex_dump_bytes
  drivers/tty/moxa.c: Put correct tty value
  TTY: tty_io, annotate locking functions
  TTY: serial_core, remove superfluous set_task_state
  TTY: serial_core, remove invalid test
  Char: moxa, fix locking in moxa_write
  ...

Fix up trivial conflicts in drivers/bluetooth/hci_ldisc.c and
drivers/tty/serial/Makefile.

I did the hci_ldisc thing as an evil merge, cleaning things up.
2011-05-23 12:23:20 -07:00
Jiri Kosina
07f9479a40 Merge branch 'master' into for-next
Fast-forwarded to current state of Linus' tree as there are patches to be
applied for files that didn't exist on the old branch.
2011-04-26 10:22:59 +02:00
Jovi Zhang
99edb3d10a tty: remove invalid location line in file header
remove invalid location line in each file header after location
moved from driver/char to driver/tty

Signed-off-by: Jovi Zhang <bookjovi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-19 16:33:36 -07:00
Uwe Kleine-König
f98e5b80ad tty: fix typo in descripton of tty_termios_encode_baud_rate
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-04-12 13:25:33 +02:00
Lucas De Marchi
25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
Alan Cox
8d075b199b tty: add a helper for setting termios data from kernel side
This basically encapsulates the small bit of locking knowledge needed. While
we are at it make sure we blow up on any more abusers and unsafe misuses of
ioctl for this kind of stuff.

We change the function to return an argument as at some point it needs to
honour the POSIX 'I asked for changes but got none of them' error reporting
corner case.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-17 12:03:52 -08:00
Greg Kroah-Hartman
96fd7ce58f TTY: create drivers/tty and move the tty core files there
The tty code should be in its own subdirectory and not in the char
driver with all of the cruft that is currently there.

Based on work done by Arnd Bergmann <arnd@arndb.de>

Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-11-05 08:10:33 -07:00