kernel/linux.git/drivers/tty/tty_io.c, branch v6.19.11

tty: use lock guard()s in tty_io

2025-04-25T11:46:31+00:00

guard()s and scoped_guard()s express more clearly what is protected by locks. And also makes the code cleaner as it can return immediately in case of short returns. Signed-off-by: Jiri Slaby (SUSE) Link: https://lore.kernel.org/r/20250425111315.1036184-3-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman

tty: tty_driver: document both {,__}tty_alloc_driver() properly

2025-03-20T15:00:51+00:00

__tty_alloc_driver()'s kernel-doc needed some care: describe the return value using the standard "Returns:", and use the new enum tty_driver_flag for @flags. Then, the tty_alloc_driver() macro was undocumented, but referenced many times in the docs. Copy the docs from the above (except the @owner parameter, obviously). Signed-off-by: Jiri Slaby (SUSE) Link: https://lore.kernel.org/r/20250317070046.24386-15-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman

Merge tag 'tty-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2025-01-28T17:55:04+00:00

Pull tty / serial driver updates from Greg KH: "Here is the tty/serial driver set of changes for 6.14-rc1. Nothing major in here, it was delayed a bit due to a regression found in linux-next which has now been reverted and verified that it is fixed. Other than the reverts, highlights include: - 8250 work to get the nbcon mode working (partially reverted) - altera_jtaguart minor fixes - fsl_lpuart minor updates - sh-sci driver minor updatesa - other tiny driver updates and cleanups All of these have been in linux-next for a while, and now with no reports of problems (thanks to the reverts)" * tag 'tty-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (44 commits) Revert "serial: 8250: Switch to nbcon console" Revert "serial: 8250: Revert "drop lockdep annotation from serial8250_clear_IER()"" serial: sh-sci: Increment the runtime usage counter for the earlycon device serial: sh-sci: Clean sci_ports[0] after at earlycon exit serial: sh-sci: Do not probe the serial port if its slot in sci_ports[] is in use serial: sh-sci: Move runtime PM enable to sci_probe_single() serial: sh-sci: Drop __initdata macro for port_cfg serial: kgdb_nmi: Remove unused knock code tty: Permit some TIOCL_SETSEL modes without CAP_SYS_ADMIN tty: xilinx_uartps: split sysrq handling serial: 8250: Revert "drop lockdep annotation from serial8250_clear_IER()" serial: 8250: Switch to nbcon console serial: 8250: Provide flag for IER toggling for RS485 serial: 8250: Use high-level writing function for FIFO serial: 8250: Use frame time to determine timeout serial: 8250: Adjust the timeout for FIFO mode tty: atmel_serial: Use of_property_present() for non-boolean properties serial: sc16is7xx: Add polling mode if no IRQ pin is available dt-bindings: serial: sc16is7xx: Add description for polling mode tty: serial: atmel: make it selectable for ARCH_LAN969X ...

drivers: remove get_task_comm() and print task comm directly

2025-01-13T04:21:16+00:00

Since task->comm is guaranteed to be NUL-terminated, we can print it directly without the need to copy it into a separate buffer. This simplifies the code and avoids unnecessary operations. Link: https://lkml.kernel.org/r/20241219023452.69907-6-laoar.shao@gmail.com Signed-off-by: Yafang Shao Reviewed-by: Jiri Slaby (For tty) Reviewed-by: Lyude Paul (For nouveau) Cc: Oded Gabbay Cc: Jani Nikula Cc: Rodrigo Vivi Cc: Joonas Lahtinen Cc: Tvrtko Ursulin Cc: David Airlie Cc: Simona Vetter Cc: Karol Herbst Cc: Lyude Paul Cc: Danilo Krummrich Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: "André Almeida" Cc: Andy Shevchenko Cc: Borislav Petkov (AMD) Cc: Darren Hart Cc: Dave Hansen Cc: Davidlohr Bueso Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: James Morris Cc: Johannes Berg Cc: Kalle Valo Cc: Kees Cook Cc: Linus Torvalds Cc: Paul Moore Cc: Peter Zijlstra Cc: Petr Mladek Cc: "Serge E. Hallyn" Cc: Thomas Gleixner Cc: Vineet Gupta Signed-off-by: Andrew Morton

tty: Make sysctl table const

2024-12-14T14:40:27+00:00

Since commit 7abc9b53bd51 ("sysctl: allow registration of const struct ctl_table"), the sysctl registration API allows for struct ctl_table to be in read-only memory. Move tty_table to be declared at build time, instead of having to be dynamically allocated at boot time. Cc: Thomas Weißschuh Suggested-by: Thomas Weißschuh Signed-off-by: Ricardo B. Marliere Link: https://lore.kernel.org/r/20241213-sysctl_const-tty-v1-1-2e2bcec77f85@suse.com Signed-off-by: Greg Kroah-Hartman

tty: ldsic: fix tty_ldisc_autoload sysctl's proc_handler

2024-11-13T14:12:19+00:00

Commit 7c0cca7c847e ("tty: ldisc: add sysctl to prevent autoloading of ldiscs") introduces the tty_ldisc_autoload sysctl with the wrong proc_handler. .extra1 and .extra2 parameters are set to avoid other values thant SYSCTL_ZERO or SYSCTL_ONE to be set but proc_dointvec do not uses them. This commit fixes this by using proc_dointvec_minmax instead of proc_dointvec. Fixes: 7c0cca7c847e ("tty: ldisc: add sysctl to prevent autoloading of ldiscs") Cc: stable Signed-off-by: Nicolas Bouchinet Reviewed-by: Lin Feng Reviewed-by: Jiri Slaby Link: https://lore.kernel.org/r/20241112131357.49582-4-nicolas.bouchinet@clip-os.org Signed-off-by: Greg Kroah-Hartman

[tree-wide] finally take no_llseek out

2024-09-27T15:18:43+00:00

no_llseek had been defined to NULL two years ago, in commit 868941b14441 ("fs: remove no_llseek") To quote that commit, At -rc1 we'll need do a mechanical removal of no_llseek - git grep -l -w no_llseek | grep -v porting.rst | while read i; do sed -i '/\/d' $i done would do it. Unfortunately, that hadn't been done. Linus, could you do that now, so that we could finally put that thing to rest? All instances are of the form .llseek = no_llseek, so it's obviously safe. Signed-off-by: Al Viro Signed-off-by: Linus Torvalds

Merge tag 'tty-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2024-09-26T16:59:50+00:00

Pull tty / serial driver updates from Greg KH: "Here is the "big" set of tty/serial driver updates for 6.12-rc1. Nothing major in here, just nice forward progress in the slow cleanup of the serial apis, and lots of other driver updates and fixes. Included in here are: - serial api updates from Jiri to make things more uniform and sane - 8250_platform driver cleanups - samsung serial driver fixes and updates - qcom-geni serial driver fixes from Johan for the bizarre UART engine that that chip seems to have. Hopefully it's in a better state now, but hardware designers still seem to come up with more ways to make broken UARTS 40+ years after this all should have finished. - sc16is7xx driver updates - omap 8250 driver updates - 8250_bcm2835aux driver updates - a few new serial driver bindings added - other serial minor driver updates All of these have been in linux-next for a long time with no reported problems" * tag 'tty-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (65 commits) tty: serial: samsung: Fix serial rx on Apple A7-A9 tty: serial: samsung: Fix A7-A11 serial earlycon SError tty: serial: samsung: Use bit manipulation macros for APPLE_S5L_* tty: rp2: Fix reset with non forgiving PCIe host bridges serial: 8250_aspeed_vuart: Enable module autoloading serial: qcom-geni: fix polled console corruption serial: qcom-geni: disable interrupts during console writes serial: qcom-geni: fix console corruption serial: qcom-geni: introduce qcom_geni_serial_poll_bitfield() serial: qcom-geni: fix arg types for qcom_geni_serial_poll_bit() soc: qcom: geni-se: add GP_LENGTH/IRQ_EN_SET/IRQ_EN_CLEAR registers serial: qcom-geni: fix false console tx restart serial: qcom-geni: fix fifo polling timeout tty: hvc: convert comma to semicolon mxser: convert comma to semicolon serial: 8250_bcm2835aux: Fix clock imbalance in PM resume serial: sc16is7xx: convert bitmask definitions to use BIT() macro serial: sc16is7xx: fix copy-paste errors in EFR_SWFLOWx_BIT constants serial: sc16is7xx: remove SC16IS7XX_MSR_DELTA_MASK serial: xilinx_uartps: Make cdns_rs485_supported static ...

Merge tag 'printk-for-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

2024-09-17T06:52:28+00:00

Pull printk updates from Petr Mladek: "This is the "last" part of the support for the new nbcon consoles. Where "nbcon" stays for "No Big console lock CONsoles" aka not under the console_lock. New callbacks are added to struct console: - write_thread() for flushing nbcon consoles in task context. - write_atomic() for flushing nbcon consoles in atomic context, including NMI. - con->device_lock() and device_unlock() for taking the driver specific lock, for example, port->lock. New printk-specific kthreads are created: - per-console kthreads which get responsible for flushing normal priority messages on nbcon consoles. - thread which gets responsible for flushing normal priority messages on all consoles when CONFIG_RT enabled. The new callbacks are called under a special per-console lock which has already been added back in v6.7. It allows to distinguish three severities: normal, emergency, and panic. A context with a higher priority could take over the ownership when it is safe even in the middle of handling a record. The panic context could do it even when it is not safe. But it is allowed only for the final desperate flush before entering the infinite loop. The new lock helps to flush the messages directly in emergency and panic contexts. But it is not enough in all situations: - console_lock() is still need for synchronization against boot consoles. - con->device_lock() is need for synchronization against other operations on the same HW, e.g. serial port speed setting, non-printk related read/write. The dependency on con->device_lock() is mutual. Any code taking the driver specific lock has to acquire the related nbcon console context as well. For example, see the new uart_port_lock() API. It provides the necessary synchronization against emergency and panic contexts where the messages are flushed only under the new per-console lock. Maybe surprisingly, a quite tricky part is the decision how to flush the consoles in various situations. It has to take into account: - message priority: normal, emergency, panic - scheduling context: task, atomic, deferred_legacy - registered consoles: boot, legacy, nbcon - threads are running: early boot, suspend, shutdown, panic - caller: printk(), pr_flush(), printk_flush_in_panic(), console_unlock(), console_start(), ... The primary decision is made in printk_get_console_flush_type(). It creates a hint what the caller should do: - flush nbcon consoles directly or via the kthread - call the legacy loop (console_unlock()) directly or via irq_work The existing behavior is preserved for the legacy consoles. The only exception is that they are not longer flushed directly from printk() in panic() before CPUs are stopped. But this blocking happens only when at least one nbcon console is registered. The motivation is to increase a chance to produce the crash dump. They legacy consoles might create a deadlock in compare with nbcon consoles. The nbcon console should allow to see the messages even when the crash dump fails. There are three possible ways how nbcon consoles are flushed: - The per-nbcon-console kthread is responsible for flushing messages added with the normal priority. This is the default mode. - The legacy loop, aka console_unlock(), is used when there is still a boot console registered. There is no easy way how to match an early console driver with a nbcon console driver. And the console_lock() provides the only reliable serialization at the moment. The legacy loop uses either con->write_atomic() or con->write_thread() callbacks depending on whether it is allowed to schedule. The atomic variant has to be used from printk(). - In other situations, the messages are flushed directly using write_atomic() which can be called in any context, including NMI. It is primary needed during early boot or shutdown, in emergency situations, and panic. The emergency priority is used by a code called within nbcon_cpu_emergency_enter()/exit(). At the moment, it is used in four situations: WARN(), Oops, lockdep, and RCU stall reports. Finally, there is no nbcon console at the moment. It means that the changes should _not_ modify the existing behavior. The only exception is CONFIG_RT which would force offloading the legacy loop, for normal priority context, into the dedicated kthread" * tag 'printk-for-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (54 commits) printk: Avoid false positive lockdep report for legacy printing printk: nbcon: Assign nice -20 for printing threads printk: Implement legacy printer kthread for PREEMPT_RT tty: sysfs: Add nbcon support for 'active' proc: Add nbcon support for /proc/consoles proc: consoles: Add notation to c_start/c_stop printk: nbcon: Show replay message on takeover printk: Provide helper for message prepending printk: nbcon: Rely on kthreads for normal operation printk: nbcon: Use thread callback if in task context for legacy printk: nbcon: Relocate nbcon_atomic_emit_one() printk: nbcon: Introduce printer kthreads printk: nbcon: Init @nbcon_seq to highest possible printk: nbcon: Add context to usable() and emit() printk: Flush console on unregister_console() printk: Fail pr_flush() if before SYSTEM_SCHEDULING printk: nbcon: Add function for printers to reacquire ownership printk: nbcon: Use raw_cpu_ptr() instead of open coding printk: Use the BITS_PER_LONG macro lockdep: Mark emergency sections in lockdep splats ...

tty: sysfs: Add nbcon support for 'active'

2024-09-04T13:56:33+00:00

Allow the 'active' attribute to list nbcon consoles. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/20240904120536.115780-15-john.ogness@linutronix.de Signed-off-by: Petr Mladek