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path: root/include/linux/tty_driver.h
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2014-09-23tty: Serialize tty flow control changes with flow_lockPeter Hurley
Without serialization, the flow control state can become inverted wrt. the actual hardware state. For example, CPU 0 | CPU 1 stop_tty() | lock ctrl_lock | tty->stopped = 1 | unlock ctrl_lock | | start_tty() | lock ctrl_lock | tty->stopped = 0 | unlock ctrl_lock | driver->start() driver->stop() | In this case, the flow control state now indicates the tty has been started, but the actual hardware state has actually been stopped. Introduce tty->flow_lock spinlock to serialize tty flow control changes. Split out unlocked __start_tty()/__stop_tty() flavors for use by ioctl(TCXONC) in follow-on patch. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-10tty: Document locking for tty driver methodsPeter Hurley
The tty core calls the tty driver's open, close and hangup methods holding the tty lock. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-02-04tty: Document required behavior of tty driver close()Peter Hurley
If the tty driver open() fails, the tty driver close() is still called during the resultant tty release. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-08-13TTY: move cdev_add to tty_register_deviceJiri Slaby
We need the /dev/ node not to be available before we call tty_register_device. Otherwise we might race with open and tty_struct->port might not be available at that time. This is not an issue now, but would be a problem after "TTY: use tty_port_register_device" is applied. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-08-13TTY: add support for unnumbered device nodesJiri Slaby
This allows drivers like ttyprintk to avoid hacks to create an unnumbered node in /dev. It used to set TTY_DRIVER_DYNAMIC_DEV in flags and call device_create on its own. That is incorrect, because TTY_DRIVER_DYNAMIC_DEV may be set only if tty_register_device is called explicitly. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-08-13TTY: pty, switch to tty_alloc_driverJiri Slaby
Switch to the new driver allocation interface, as this is one of the special call-sites. Here, we need TTY_DRIVER_DYNAMIC_ALLOC to not allocate tty_driver->ports, cdevs and potentially other structures because we reserve too many lines in pty. Instead, it provides the tty_port<->tty_struct link in tty->ops->install already. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-08-10TTY: pass flags to alloc_tty_driverJiri Slaby
We need to allow drivers that use neither tty_port_install nor tty_port_register_device to link a tty_port to a tty somehow. To avoid a race with open, this has to be performed before tty_register_device. But currently tty_driver->ports is allocated even in tty_register_device because we do not know whether this is the PTY driver. The PTY driver is special here due to an excessive count of lines it declares to handle. We cannot handle tty_ports there this way. To circumvent this, we start passing tty_driver flags to alloc_tty_driver already and we create tty_alloc_driver for this purpose. There we can allocate tty_driver->ports and do all the magic between tty_alloc_driver and tty_register_device. Later we will introduce tty_port_link_device function for that purpose. All drivers should eventually switch to this new tty driver allocation interface. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-17tty: Move the handling of the tty release logicAlan Cox
Now that we don't have tty->termios tied to drivers->tty we can untangle the logic here. In addition we can push the removal logic out of the destructor path. At that point we can think about sorting out tty_port and console and all the other ugly hangovers. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-13TTY: add ports array to tty_driverJiri Slaby
It will hold tty_port structures for all drivers which do not want to define tty->ops->install hook. We ignore PTY here because it wants 1 million lines and it installs tty_port in ->install anyway. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-03-08TTY: tty_driver, document tty->ops->shutdown limitationJiri Slaby
Note that tty->ops->shutdown is called from whatever context the user drops the last tty reference from. E.g. if one takes a reference in an ISR, tty close happens on other CPU and the final tty put is from the ISR, tty->ops->shutdown will be called from that hard irq context. We would have a problem in vt if we start using tty refcounting from other contexts than user there. It is because vt's shutdown uses mutexes. This is yet to be fixed. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-03-08TTY: remove minor_num from tty_driverJiri Slaby
It was added back in 2004 and never used for anything real. Remove the only assignment in the tree as well. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-03-08TTY: let alloc_tty_driver deduce the owner automaticallyJiri Slaby
Like the rest of the kernel, make a stub from alloc_tty_driver which calls __alloc_tty_driver with proper owner. This will save us one more assignment on the driver side. Also this fixes some drivers which didn't set the owner. This allowed user to remove the module from the system even though a tty from the driver is still open. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-01-17tty: remove unused tty_driver->termios_lockedKonstantin Khlebnikov
This field is unused since 2.6.28 (commit fe6e29fdb1a7: "tty: simplify ktermios allocation", to be exact) Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-23TTY: pty, fix pty countingJiri Slaby
tty_operations->remove is normally called like: queue_release_one_tty ->tty_shutdown ->tty_driver_remove_tty ->tty_operations->remove However tty_shutdown() is called from queue_release_one_tty() only if tty_operations->shutdown is NULL. But for pty, it is not. pty_unix98_shutdown() is used there as ->shutdown. So tty_operations->remove of pty (i.e. pty_unix98_remove()) is never called. This results in invalid pty_count. I.e. what can be seen in /proc/sys/kernel/pty/nr. I see this was already reported at: https://lkml.org/lkml/2009/11/5/370 But it was not fixed since then. This patch is kind of a hackish way. The problem lies in ->install. We allocate there another tty (so-called tty->link). So ->install is called once, but ->remove twice, for both tty and tty->link. The fix here is to count both tty and tty->link and divide the count by 2 for user. And to have ->remove called, let's make tty_driver_remove_tty() global and call that from pty_unix98_shutdown() (tty_operations->shutdown). While at it, let's document that when ->shutdown is defined, tty_shutdown() is not called. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Alan Cox <alan@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-17tty: now phase out the ioctl file pointer for goodAlan Cox
Only oddities here are a couple of drivers that bogusly called the ldisc helpers instead of returning -ENOIOCTLCMD. Fix the bug and the rest goes away. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-17tiocmset: kill the file pointer argumentAlan Cox
Doing tiocmget was such fun we should do tiocmset as well for the same reasons Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-17tiocmget: kill off the passing of the struct fileAlan Cox
We don't actually need this and it causes problems for internal use of this functionality. Currently there is a single use of the FILE * pointer. That is the serial core which uses it to check tty_hung_up_p. However if that is true then IO_ERROR is also already set so the check may be removed. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-12-16tty: fix typos/errors in tty_driver.h commentsTimur Tabi
Fix various typos and other errors in comments of tty_driver.h. The most significant is the wrong name of a function for the description of TTY_DRIVER_DYNAMIC_DEV. Signed-off-by: Timur Tabi <timur@freescale.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-11-16TTY: include termios.h in tty_driver.hJiri Slaby
We reference termios and termiox in tty_driver.h, but we do not include linux/termios.h where these are defined. Add the #include properly. Otherwise when we include tty_driver.h, we get compile errors. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Greg KH <gregkh@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-10-22tty: Make tiocgicount a handlerAlan Cox
Dan Rosenberg noted that various drivers return the struct with uncleared fields. Instead of spending forever trying to stomp all the drivers that get it wrong (and every new driver) do the job in one place. This first patch adds the needed operations and hooks them up, including the needed USB midlayer and serial core plumbing. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-09-27tty: Fix regressions caused by commit b50989dcDave Young
The following commit made console open fails while booting: commit b50989dc444599c8b21edc23536fc305f4e9b7d5 Author: Alan Cox <alan@linux.intel.com> Date: Sat Sep 19 13:13:22 2009 -0700 tty: make the kref destructor occur asynchronously Due to tty release routines run in a workqueue now, error like the following will be reported while booting: INIT open /dev/console Input/output error It also causes hibernation regression to appear as reported at http://bugzilla.kernel.org/show_bug.cgi?id=14229 The reason is that now there's latency issue with closing, but when we open a "closing not finished" tty, -EIO will be returned. Fix it as per the following Alan's suggestion: Fun but it's actually not a bug and the fix is wrong in itself as the port may be closing but not yet being destructed, in which case it seems to do the wrong thing. Opening a tty that is closing (and could be closing for long periods) is supposed to return -EIO. I suspect a better way to deal with this and keep the old console timing is to split tty->shutdown into two functions. tty->shutdown() - called synchronously just before we dump the tty onto the waitqueue for destruction tty->cleanup() - called when the destructor runs. We would then do the shutdown part which can occur in IRQ context fine, before queueing the rest of the release (from tty->magic = 0 ... the end) to occur asynchronously The USB update in -next would then need a call like if (tty->cleanup) tty->cleanup(tty); at the top of the async function and the USB shutdown to be split between shutdown and cleanup as the USB resource cleanup and final tidy cannot occur synchronously as it needs to sleep. In other words the logic becomes final kref put make object unfindable async clean it up Signed-off-by: Dave Young <hidave.darkstar@gmail.com> [ rjw: Rebased on top of 2.6.31-git, reworked the changelog. ] Signed-off-by: "Rafael J. Wysocki" <rjw@sisk.pl> [ Changed serial naming to match new rules, dropped tty_shutdown as per comments from Alan Stern - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11tty: throttling race fixAlan Cox
The tty throttling code can race due to the lock drops. It takes very high loads but this has been observed and verified by Rob Duncan. The basic problem is that on an SMP box we can go CPU #1 CPU #2 need to throttle ? suppose we should buffer space cleared are we throttled yes ? - unthrottle call throttle method This changeet take the termios lock to protect against this. The termios lock isn't the initial obvious candidate but many implementations of throttle methods already need to poke around their own termios structures (and nobody really locks them against a racing change of flow control). This does mean that anyone who is setting tty->low_latency = 1 and then calling tty_flip_buffer_push from their unthrottle method is going to end up collapsing in a pile of locks. However we've removed all the known bogus users of low_latency = 1 and such use isn't safe anyway for other reasons so catching it would be an improvement. Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07tty: Correct inline types for tty_driver_kref_get()Adrian Bunk
tty_driver_kref_get() should be static inline and not extern inline (the latter even changed it's semantics in gcc >= 4.3). Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01proc tty: remove struct tty_operations::read_procAlexey Dobriyan
struct tty_operations::proc_fops took it's place and there is one less create_proc_read_entry() user now! Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01proc tty: add struct tty_operations::proc_fopsAlexey Dobriyan
Used for gradual switch of TTY drivers from using ->read_proc which helps with gradual switch from ->read_proc for the whole tree. As side effect, fix possible race condition when ->data initialized after PDE is hooked into proc tree. ->proc_fops takes precedence over ->read_proc. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02pty: simplify resizeAlan Cox
We have special case logic for resizing pty/tty pairs. We also have a per driver resize method so for the pty case we should use it. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13Add an instance parameter devpts interfacesSukadev Bhattiprolu
Pass-in 'inode' or 'tty' parameter to devpts interfaces. With multiple devpts instances, these parameters will be used in subsequent patches to identify the instance of devpts mounted. The parameters also help simplify devpts implementation. Changelog[v3]: - minor changes due to merge with ttydev updates - rename parameters to emphasize they are ptmx or pts inodes - pass-in tty_struct * to devpts_pty_kill() (this will help cleanup the get_node() call in a subsequent patch) Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13tty: More driver operationsAlan Cox
We have the lookup operation abstracted which is nice for pty cleanup but we really want to abstract the add/remove entries as well so that we can pull the pty code out of the tty core and create a clear defined interface for the tty driver table. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13tty: kref the tty driver objectAlan Cox
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13tty: Clean up the tty_init_dev changes furtherAlan Cox
Fix up the naming, style and extract some bits of code into the driver specific code Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13tty: shutdown methodAlan Cox
Right now there are various drivers that try to use tty->count to know when they get the final close. Aristeau Rozanski showed while debugging the vt sysfs race that this isn't entirely safe. Instead of driver side tricks to work around this introduce a shutdown which is called when the tty is being destructed. This also means that the shutdown method is tied into the refcounting. Use this to rework the console close/sysfs logic. Remove lots of special case code from the tty core code. The pty code can now have a shutdown() method that replaces the special case hackery in the tree free up paths. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13tty: Add termioxAlan Cox
We need a way to describe the various additional modes and flow control features that random weird hardware shows up and software such as wine wants to emulate as Windows supports them. TCGETX/TCSETX and the termiox ioctl are a SYS5 extension that we might as well adopt. This patches adds the structures and the basic ioctl interfaces when the TCGETX etc defines are added for an architecture. Drivers wishing to use this stuff need to add new methods. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-15tty: remove resize window special caseAlan Cox
This moves it to being a tty operation. That removes special cases and now also means that resize can be picked up by um and other non vt consoles which may have a resize operation. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-22tty: rework break handlingAlan Cox
Some hardware needs to do break handling itself and may have partial support only. Make break_ctl return an error code. Add a tty driver flag so you can indicate driver hardware side break support. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-06-23tty_driver: Update required method documentationAlan Cox
Some of the requirement rules are now more relaxed. Also correct a contradiction in the previous update Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30tty: add throttle/unthrottle helpersAlan Cox
Something Arjan suggested which allows us to clean up the code nicely Signed-off-by: Alan Cox <alan@redhat.com> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30tty: The big operations reworkAlan Cox
- Operations are now a shared const function block as with most other Linux objects - Introduce wrappers for some optional functions to get consistent behaviour - Wrap put_char which used to be patched by the tty layer - Document which functions are needed/optional - Make put_char report success/fail - Cache the driver->ops pointer in the tty as tty->ops - Remove various surplus lock calls we no longer need - Remove proc_write method as noted by Alexey Dobriyan - Introduce some missing sanity checks where certain driver/ldisc combinations would oops as they didn't check needed methods were present [akpm@linux-foundation.org: fix fs/compat_ioctl.c build] [akpm@linux-foundation.org: fix isicom] [akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build] [akpm@linux-foundation.org: fix kgdb] Signed-off-by: Alan Cox <alan@redhat.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Cc: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-17consoles: polling support, kgdbocJason Wessel
polled console handling support, to access a console in an irq-less way while in debug or irq context. absolutely zero impact as long as CONFIG_CONSOLE_POLL is disabled. (which is the default) [ jan.kiszka@siemens.com: lots of cleanups ] [ mingo@elte.hu: redesign, splitups, cleanups. ] Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jan Kiszka <jan.kiszka@web.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
2007-05-11tty: add compat_ioctlPaul Fulghum
Add compat_ioctl method for tty code to allow processing of 32 bit ioctl calls on 64 bit systems by tty core, tty drivers, and line disciplines. Based on patch by Arnd Bergmann: http://www.uwsg.iu.edu/hypermail/linux/kernel/0511.0/1732.html [akpm@linux-foundation.org: make things static] Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-12-08[PATCH] tty: switch to ktermios and new frameworkAlan Cox
This is the core of the switch to the new framework. I've split it from the driver patches which are mostly search/replace and would encourage people to give this one a good hard stare. The references to BOTHER and ISHIFT are the termios values that must be defined by a platform once it wants to turn on "new style" ioctl support. The code patches here ensure that providing 1. The termios overlays the ktermios in memory 2. The only new kernel only fields are c_ispeed/c_ospeed (or none) the existing behaviour is retained. This is true for the patches at this point in time. Future patches will define BOTHER, ISHIFT and enable newer termios structures for each architecture, and once they are all done some of the ifdefs also vanish. [akpm@osdl.org: warning fix] [akpm@osdl.org: IRDA fix] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-02[PATCH] const struct tty_operationsJeff Dike
As part of an SMP cleanliness pass over UML, I consted a bunch of structures in order to not have to document their locking. One of these structures was a struct tty_operations. In order to const it in UML without introducing compiler complaints, the declaration of tty_set_operations needs to be changed, and then all of its callers need to be fixed. This patch declares all struct tty_operations in the tree as const. In all cases, they are static and used only as input to tty_set_operations. As an extra check, I ran an i386 allyesconfig build which produced no extra warnings. 53 drivers are affected. I checked the history of a bunch of them, and in most cases, there have been only a handful of maintenance changes in the last six months. serial_core.c was the busiest one that I looked at. Signed-off-by: Jeff Dike <jdike@addtoit.com> Acked-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] devfs: Rename TTY_DRIVER_NO_DEVFS to TTY_DRIVER_DYNAMIC_DEVGreg Kroah-Hartman
I've always found this flag confusing. Now that devfs is no longer around, it has been renamed, and the documentation for when this flag should be used has been updated. Also fixes all drivers that use this flag. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-06-26[PATCH] devfs: Remove the tty_driver devfs_name field as it's no longer neededGreg Kroah-Hartman
Also fixes all drivers that set this field. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-04-16Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!