kernel/linux.git/drivers/tty/Kconfig, branch v4.14.263

tty: ldisc: add sysctl to prevent autoloading of ldiscs

2019-04-17T06:37:45+00:00

commit 7c0cca7c847e6e019d67b7d793efbbe3b947d004 upstream. By default, the kernel will automatically load the module of any line dicipline that is asked for. As this sometimes isn't the safest thing to do, provide a sysctl to disable this feature. By default, we set this to 'y' as that is the historical way that Linux has worked, and we do not want to break working systems. But in the future, perhaps this can default to 'n' to prevent this functionality. Signed-off-by: Greg Kroah-Hartman Reviewed-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

tty: goldfish: Enable 'earlycon' only if built-in

2018-03-24T10:01:23+00:00

[ Upstream commit 6a28fd2bbc94bfca105632e5ef8a9dbe63ba0b39 ] Commit 3840ed9548f7 ("tty: goldfish: Implement support for kernel 'earlycon' parameter") breaks an allmodconfig config on x86: | LD vmlinux.o | MODPOST vmlinux.o |drivers/tty/serial/earlycon.o: In function `parse_options': |drivers/tty/serial/earlycon.c:97: undefined reference to `uart_parse_earlycon' |Makefile:1005: recipe for target 'vmlinux' failed earlycon.c::parse_options() invokes uart_parse_earlycon() from serial_core.c which is compiled=m because GOLDFISH_TTY itself (and most others) are =m. To avoid that, I'm adding the _CONSOLE config option which is selected if the GOLDFISH module itself is =y since it doesn't need the early bits for the =m case (other drivers do the same dance). The alternative would be to move uart_parse_earlycon() from serial_core.c to earlycon.c (we don't have that many users of that function). Fixes: 3840ed9548f7 ("tty: goldfish: Implement support for kernel 'earlycon' parameter") Signed-off-by: Sebastian Andrzej Siewior Reviewed-by: Miodrag Dinic Acked-by: Miodrag Dinic Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next

2017-09-10T16:57:23+00:00

Pull sparc updates from David Miller: 1) Use register window state adjustment instructions when available, from Anthony Yznaga. 2) Add VCC console concentrator driver, from Jag Raman. 3) Add 16GB hugepage support, from Nitin Gupta. 4) Support cpu 'poke' hypercall, from Vijay Kumar. 5) Add M7/M8 optimized memcpy/memset/copy_{to,from}_user, from Babu Moger. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next: (33 commits) sparc64: Handle additional cases of no fault loads sparc64: speed up etrap/rtrap on NG2 and later processors sparc64: vcc: make ktermios const sparc: leon: grpci1: constify of_device_id sparc: leon: grpci2: constify of_device_id sparc64: vcc: Check for IS_ERR() instead of NULL sparc64: Cleanup hugepage table walk functions sparc64: Add 16GB hugepage support sparc64: Support huge PUD case in get_user_pages sparc64: vcc: Add install & cleanup TTY operations sparc64: vcc: Add break_ctl TTY operation sparc64: vcc: Add chars_in_buffer TTY operation sparc64: vcc: Add write & write_room TTY operations sparc64: vcc: Add hangup TTY operation sparc64: vcc: Add open & close TTY operations sparc64: vcc: Enable LDC event processing engine sparc64: vcc: Add RX & TX timer for delayed LDC operation sparc64: vcc: Create sysfs attribute group sparc64: vcc: Enable VCC port probe and removal sparc64: vcc: TTY driver initialization and cleanup ...

tty: goldfish: Implement support for kernel 'earlycon' parameter

2017-08-31T16:58:45+00:00

Add early console functionality to the Goldfish tty driver. When 'earlycon' kernel command line parameter is used with no options, the early console is determined by the 'stdout-path' property in device tree's 'chosen' node. This is illustrated in the following device tree source example: Device tree example: chosen { stdout-path = "/goldfish_tty@1f004000"; }; goldfish_tty@1f004000 { interrupts = <0xc>; reg = <0x1f004000 0x0 0x1000>; compatible = "google,goldfish-tty"; }; Signed-off-by: Miodrag Dinic Signed-off-by: Goran Ferenc Signed-off-by: Aleksandar Markovic Signed-off-by: Greg Kroah-Hartman

sparc64: vcc: Enable VCC module in linux

2017-08-16T04:33:50+00:00

Enables the Virtual Console Concentrator (VCC) module in linux kernel Signed-off-by: Jagannathan Raman Reviewed-by: Liam Merwick Reviewed-by: Shannon Nelson Signed-off-by: David S. Miller

devpts: Make each mount of devpts an independent filesystem.

2016-06-05T17:36:01+00:00

The /dev/ptmx device node is changed to lookup the directory entry "pts" in the same directory as the /dev/ptmx device node was opened in. If there is a "pts" entry and that entry is a devpts filesystem /dev/ptmx uses that filesystem. Otherwise the open of /dev/ptmx fails. The DEVPTS_MULTIPLE_INSTANCES configuration option is removed, so that userspace can now safely depend on each mount of devpts creating a new instance of the filesystem. Each mount of devpts is now a separate and equal filesystem. Reserved ttys are now available to all instances of devpts where the mounter is in the initial mount namespace. A new vfs helper path_pts is introduced that finds a directory entry named "pts" in the directory of the passed in path, and changes the passed in path to point to it. The helper path_pts uses a function path_parent_directory that was factored out of follow_dotdot. In the implementation of devpts: - devpts_mnt is killed as it is no longer meaningful if all mounts of devpts are equal. - pts_sb_from_inode is replaced by just inode->i_sb as all cached inodes in the tty layer are now from the devpts filesystem. - devpts_add_ref is rolled into the new function devpts_ptmx. And the unnecessary inode hold is removed. - devpts_del_ref is renamed devpts_release and reduced to just a deacrivate_super. - The newinstance mount option continues to be accepted but is now ignored. In devpts_fs.h definitions for when !CONFIG_UNIX98_PTYS are removed as they are never used. Documentation/filesystems/devices.txt is updated to describe the current situation. This has been verified to work properly on openwrt-15.05, centos5, centos6, centos7, debian-6.0.2, debian-7.9, debian-8.2, ubuntu-14.04.3, ubuntu-15.10, fedora23, magia-5, mint-17.3, opensuse-42.1, slackware-14.1, gentoo-20151225 (13.0?), archlinux-2015-12-01. With the caveat that on centos6 and on slackware-14.1 that there wind up being two instances of the devpts filesystem mounted on /dev/pts, the lower copy does not end up getting used. Signed-off-by: "Eric W. Biederman" Cc: Greg KH Cc: Peter Hurley Cc: Peter Anvin Cc: Andy Lutomirski Cc: Al Viro Cc: Serge Hallyn Cc: Willy Tarreau Cc: Aurelien Jarno Cc: One Thousand Gnomes Cc: Jann Horn Cc: Jiri Slaby Cc: Florian Weimer Cc: Konstantin Khlebnikov Signed-off-by: Linus Torvalds

tty: cyclades: cyz_interrupt is only used for PCI

2016-02-07T07:41:17+00:00

When CONFIG_PCI is not set, enabling CONFIG_CYZ_INTR has no practical effect other than generating a warning about an unused function: drivers/tty/cyclades.c:1184:20: warning: 'cyz_interrupt' defined but not used [-Wunused-function] static irqreturn_t cyz_interrupt(int irq, void *dev_id) This adds a dependency to avoid that warning. Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

ttyFDC: Implement KGDB IO operations.

2015-03-31T10:04:13+00:00

Implement KGDB IO operations for MIPS Fast Debug Channel (FDC). This can be enabled via Kconfig, which also allows the channel number to be chosen. The magic sysrq hack is implemented in the TTY driver, detecting just ^C for the KGDB channel, and ^O followed by a letter for the FDC console channel. The KGDB operations are reasonably efficient thanks to the flush callback, with a 4 byte buffer being used in both directions to allow up to 4 bytes to be encoded per FDC word. Reading of data for KGDB will discard any data received on other channels, which clearly isn't ideal, but given that there is a single FIFO shared between channels we can't do much better. Signed-off-by: James Hogan Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: Jason Wessel Cc: linux-mips@linux-mips.org Cc: kgdb-bugreport@lists.sourceforge.net Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/9147/ Signed-off-by: Ralf Baechle

MIPS, ttyFDC: Add early FDC console support

2015-03-31T10:04:12+00:00

Add support for early console of MIPS Fast Debug Channel (FDC) on channel 1 with a call very early from the MIPS setup_arch(). Signed-off-by: James Hogan Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/9145/ Signed-off-by: Ralf Baechle

TTY: Add MIPS EJTAG Fast Debug Channel TTY driver

2015-03-31T10:04:12+00:00

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 Cc: Ralf Baechle Cc: Greg Kroah-Hartman Cc: Jiri Slaby 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