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2019-04-16tty: Add NULL TTY driverVincent Whitchurch1-0/+1
If no console driver is enabled (or if a non-present driver is selected with something like console=null in an attempt to disable the console), opening /dev/console errors out, and init scripts and other userspace code that relies on the existence of a console will fail. Symlinking /dev/null to /dev/console does not solve the problem since /dev/null does not behave like a real TTY. To just provide a dummy console to userspace when no console driver is available or desired, add a ttynull driver which simply discards all writes. It can be chosen on the command line in the standard way, i.e. with console=ttynull. Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-26tty: remove bfin_jtag_comm and hvc_bfin_jtag driversArnd Bergmann1-1/+0
The blackfin architecture is getting removed, so these drivers are not needed any more. Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Aaron Wu <aaron.wu@analog.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2018-03-05tty: Remove metag DA TTY and console driverJames Hogan1-1/+0
Now that arch/metag/ has been removed, remove the metag DA TTY and console driver. It is of no value without the architecture code. Signed-off-by: James Hogan <jhogan@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: linux-metag@vger.kernel.org
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman1-0/+1
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-16sparc64: vcc: Enable VCC module in linuxJag Raman1-0/+1
Enables the Virtual Console Concentrator (VCC) module in linux kernel Signed-off-by: Jagannathan Raman <jag.raman@oracle.com> Reviewed-by: Liam Merwick <liam.merwick@oracle.com> Reviewed-by: Shannon Nelson <shannon.nelson@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-03tty: handle the case where we cannot restore a line disciplineAlan Cox1-1/+2
Historically the N_TTY driver could never fail but this has become broken over time. Rather than trying to rewrite half the ldisc layer to fix the breakage introduce a second level of fallback with an N_NULL ldisc which cannot fail, and thus restore the guarantees required by the ldisc layer. We still try and fail to N_TTY first. It's much more useful to find yourself back in your old ldisc (first attempt) or in N_TTY (second attempt), and while I'm not aware of any code out there that makes those assumptions it's good to drive(r) defensively. Signed-off-by: Alan Cox <alan@linux.intel.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-18tty: split job control support into a file of its ownNicolas Pitre1-1/+1
This makes it easier for job control to become optional and/or usable independently from tty_io.c, as well as providing a nice purpose separation. No logical changes from this patch. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-18tty: move baudrate handling code to a file of its ownNicolas Pitre1-1/+2
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>
2017-02-03serdev: Introduce new bus for serial attached devicesRob Herring1-0/+1
The serdev bus is designed for devices such as Bluetooth, WiFi, GPS and NFC connected to UARTs on host processors. Tradionally these have been handled with tty line disciplines, rfkill, and userspace glue such as hciattach. This approach has many drawbacks since it doesn't fit into the Linux driver model. Handling of sideband signals, power control and firmware loading are the main issues. This creates a serdev bus with controllers (i.e. host serial ports) and attached devices. Typically, these are point to point connections, but some devices have muxing protocols or a h/w mux is conceivable. Any muxing is not yet supported with the serdev bus. Signed-off-by: Rob Herring <robh@kernel.org> Reviewed-By: Sebastian Reichel <sre@kernel.org> Tested-By: Sebastian Reichel <sre@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-31TTY: Add MIPS EJTAG Fast Debug Channel TTY driverJames Hogan1-0/+1
Add TTY driver and consoles for the MIPS EJTAG Fast Debug Channel (FDC), which is found on the per-CPU MIPS Common Device Mapped Memory (CDMM) bus. The FDC is a per-CPU device which is used to communicate with an EJTAG probe. RX and TX FIFOs exist, containing 32-bits of data and 4-bit channel numbers. 16 general data streams are implemented on this for TTY and console use by encoding up to 4 bytes on each 32-bit FDC word. The TTY devices are named e.g. /dev/ttyFDC3c2 for channel 2 of the FDC attached to logical CPU 3. These can be used for getting the kernel log, a login prompt, or as a GDB remote transport, all over EJTAG and without needing a serial port. It can have an interrupt to notify of when incoming data is available in the RX FIFO or when the TX FIFO is no longer full. The detection of this interrupt occurs in architecture / platform code, but it may be shared with the timer and/or performance counter interrupt. Due to the per-CPU nature of the hardware, all outgoing TTY data is written out from a kthread which is pinned to the appropriate CPU. The console is not bound to a specific CPU, so output will appear on the chosen channel on whichever CPU the code is executing on. Enable with e.g. console=fdc1 in kernel arguments. /dev/console is bound to the same channel on the boot CPU's FDC if it exists. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.cz> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/9146/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-05-20tty: Add timed, writer-prioritized rw semaphorePeter Hurley1-1/+1
The semantics of a rw semaphore are almost ideally suited for tty line discipline lifetime management; multiple active threads obtain "references" (read locks) while performing i/o to prevent the loss or change of the current line discipline (write lock). Unfortunately, the existing rw_semaphore is ill-suited in other ways; 1) TIOCSETD ioctl (change line discipline) expects to return an error if the line discipline cannot be exclusively locked within 5 secs. Lock wait timeouts are not supported by rwsem. 2) A tty hangup is expected to halt and scrap pending i/o, so exclusive locking must be prioritized. Writer priority is not supported by rwsem. Add ld_semaphore which implements these requirements in a semantically similar way to rw_semaphore. Writer priority is handled by separate wait lists for readers and writers. Pending write waits are priortized before existing read waits and prevent further read locks. Wait timeouts are trivially added, but obviously change the lock semantics as lock attempts can fail (but only due to timeout). This implementation incorporates the write-lock stealing work of Michel Lespinasse <walken@google.com>. Cc: Michel Lespinasse <walken@google.com> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-02-06tty: metag_da: Add metag DA TTY driverJames Hogan1-0/+1
Add a TTY driver for communicating over a Meta DA (Debug Adapter) channel using the bios channel SWITCH operation. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Jiri Slaby <jslaby@suse.cz> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-22goldfish: tty driverArve Hjønnevåg1-0/+1
This provides a console driver for the Goldfish virtual platform. The original is from Arve with changes from Jun Nakajima and Tom Keel. This has been then been ported to the current kernel and to the tty port mechanism by Alan Cox. In the process it gained proper POSIX semantics and vhangup works. The default name is not ttyS as this belongs to the 8250 driver. Instead ttyGFx is now used. In the normal usage case the first port serves as a kernel logging console and the second one carries various other data streams for the emulation. Signed-off-by: Arve Hjønnevåg <arve@google.com> [Cleaned up to handle x86] Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com> Signed-off-by: Xiaohui Xin <xiaohui.xin@intel.com> Signed-off-by: Jun Nakajima <jun.nakajima@intel.com> Signed-off-by: Bruce Beare <bruce.j.beare@intel.com> [Moved to 3.7 and chunks rewritten to use tty_port layer] Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-19tty: Added a CONFIG_TTY option to allow removal of TTYJoe Millenbach1-1/+1
The option allows you to remove TTY and compile without errors. This saves space on systems that won't support TTY interfaces anyway. bloat-o-meter output is below. The bulk of this patch consists of Kconfig changes adding "depends on TTY" to various serial devices and similar drivers that require the TTY layer. Ideally, these dependencies would occur on a common intermediate symbol such as SERIO, but most drivers "select SERIO" rather than "depends on SERIO", and "select" does not respect dependencies. bloat-o-meter output comparing our previous minimal to new minimal by removing TTY. The list is filtered to not show removed entries with awk '$3 != "-"' as the list was very long. add/remove: 0/226 grow/shrink: 2/14 up/down: 6/-35356 (-35350) function old new delta chr_dev_init 166 170 +4 allow_signal 80 82 +2 static.__warned 143 142 -1 disallow_signal 63 62 -1 __set_special_pids 95 94 -1 unregister_console 126 121 -5 start_kernel 546 541 -5 register_console 593 588 -5 copy_from_user 45 40 -5 sys_setsid 128 120 -8 sys_vhangup 32 19 -13 do_exit 1543 1526 -17 bitmap_zero 60 40 -20 arch_local_irq_save 137 117 -20 release_task 674 652 -22 static.spin_unlock_irqrestore 308 260 -48 Signed-off-by: Joe Millenbach <jmillenbach@gmail.com> Reviewed-by: Jamey Sharp <jamey@minilop.net> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2011-08-23tty/powerpc: introduce the ePAPR embedded hypervisor byte channel driverTimur Tabi1-0/+1
The ePAPR embedded hypervisor specification provides an API for "byte channels", which are serial-like virtual devices for sending and receiving streams of bytes. This driver provides Linux kernel support for byte channels via three distinct interfaces: 1) An early-console (udbg) driver. This provides early console output through a byte channel. The byte channel handle must be specified in a Kconfig option. 2) A normal console driver. Output is sent to the byte channel designated for stdout in the device tree. The console driver is for handling kernel printk calls. 3) A tty driver, which is used to handle user-space input and output. The byte channel used for the console is designated as the default tty. Signed-off-by: Timur Tabi <timur@freescale.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-14n_tracerouter and n_tracesink ldisc additions.J Freyensee1-0/+2
The n_tracerouter and n_tracesink line discpline drivers use the Linux tty line discpline framework to route trace data coming from a tty port (say UART for example) to the trace sink line discipline driver and to another tty port(say USB). Those these two line discipline drivers can be used together, independently from pti.c, they are part of the original implementation solution of the MIPI P1149.7, compact JTAG, PTI solution for Intel mobile platforms starting with the Medfield platform. Signed-off-by: J Freyensee <james_p_freyensee@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-23tty: move ipwireless driver from drivers/char/pcmcia/ to drivers/tty/Greg Kroah-Hartman1-0/+2
As planned by Arnd Bergmann, this moves the ipwireless driver to the drivers/tty/ directory as that's where it really belongs. Cc: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Jiri Slaby <jslaby@suse.cz> Cc: David Sterba <dsterba@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-23tty: move a number of tty drivers from drivers/char/ to drivers/tty/Greg Kroah-Hartman1-0/+13
As planned by Arnd Bergmann, this moves the following drivers from drivers/char/ to drivers/tty/ as that's where they really belong: amiserial nozomi synclink rocket cyclades moxa mxser isicom bfin_jtag_comm Cc: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-13tty: move drivers/serial/ to drivers/tty/serial/Greg Kroah-Hartman1-0/+1
The serial drivers are really just tty drivers, so move them to drivers/tty/ to make things a bit neater overall. This is part of the tty/serial driver movement proceedure as proposed by Arnd Bergmann and approved by everyone involved a number of months ago. Cc: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Rogier Wolff <R.E.Wolff@bitwizard.nl> Cc: Michael H. Warfield <mhw@wittsend.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-13tty: move hvc drivers to drivers/tty/hvc/Greg Kroah-Hartman1-0/+1
As requested by Arnd Bergmann, the hvc drivers are now moved to the drivers/tty/hvc/ directory. The virtio_console.c driver was also moved, as it required the hvc_console.h file to be able to be built, and it really is a hvc driver. Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-11-05TTY: create drivers/tty/vt and move the vt code thereGreg Kroah-Hartman1-0/+2
The vt and other related code is moved into the drivers/tty/vt directory. 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>
2010-11-05TTY: create drivers/tty and move the tty core files thereGreg Kroah-Hartman1-0/+9
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>