user/sven/linux.git/include/linux/console.h, branch v6.6.29

printk: Add per-console suspended state

2023-07-20T11:06:22Z

Currently the global @console_suspended is used to determine if consoles are in a suspended state. Its primary purpose is to allow usage of the console_lock when suspended without causing console printing. It is synchronized by the console_lock. Rather than relying on the console_lock to determine suspended state, make it an official per-console state that is set within console->flags. This allows the state to be queried via SRCU. Remove @console_suspended. Console printing will still be avoided when suspended because console_is_usable() returns false when the new suspended flag is set for that console. Signed-off-by: John Ogness Reviewed-by: Sergey Senozhatsky Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20230717194607.145135-7-john.ogness@linutronix.de

Merge tag 'tty-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2023-02-24T20:17:14Z

Pull tty / serial driver updates from Greg KH: "Here is the big set of serial and tty driver updates for 6.3-rc1. Once again, Jiri and Ilpo have done a number of core vt and tty/serial layer cleanups that were much needed and appreciated. Other than that, it's just a bunch of little tty/serial driver updates: - qcom-geni-serial driver updates - liteuart driver updates - hvcs driver cleanups - n_gsm updates and additions for new features - more 8250 device support added - fpga/dfl update and additions - imx serial driver updates - fsl_lpuart updates - other tiny fixes and updates for serial drivers All of these have been in linux-next for a while with no reported problems" * tag 'tty-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (143 commits) tty: n_gsm: add keep alive support serial: imx: remove a redundant check dt-bindings: serial: snps-dw-apb-uart: add dma & dma-names properties soc: qcom: geni-se: Move qcom-geni-se.h to linux/soc/qcom/geni-se.h tty: n_gsm: add TIOCMIWAIT support tty: n_gsm: add RING/CD control support tty: n_gsm: mark unusable ioctl structure fields accordingly serial: imx: get rid of registers shadowing serial: imx: refine local variables in rxint() serial: imx: stop using USR2 in FIFO reading loop serial: imx: remove redundant USR2 read from FIFO reading loop serial: imx: do not break from FIFO reading loop prematurely serial: imx: do not sysrq broken chars serial: imx: work-around for hardware RX flood serial: imx: factor-out common code to imx_uart_soft_reset() serial: 8250_pci1xxxx: Add power management functions to quad-uart driver serial: 8250_pci1xxxx: Add RS485 support to quad-uart driver serial: 8250_pci1xxxx: Add driver for quad-uart support serial: 8250_pci: Add serial8250_pci_setup_port definition in 8250_pcilib.c tty: pcn_uart: fix memory leak with using debugfs_lookup() ...

VT: Add height parameter to con_font_get/set consw operations

2023-01-19T15:28:56Z

The current con_font_get/set API currently hardcodes a 32-pixel-tall limitation, which only dates from the old VGA hardware which could not handle taller fonts than that. This change just adds a vpitch parameter to release this constraint. Drivers which do not support vpitch != 32 can just return EINVAL when it is not 32, font loading tools will revert to trying 32 and succeed. This change makes the fbcon driver consider vpitch appropriately, thus making it able to load large fonts. Signed-off-by: Samuel Thibault Link: https://lore.kernel.org/r/20230119151934.932642243@ens-lyon.org Signed-off-by: Greg Kroah-Hartman

console: Document struct console

2023-01-11T14:35:11Z

Add kerneldoc comments to struct console. Signed-off-by: Thomas Gleixner Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20230109100800.1085541-4-john.ogness@linutronix.de

console: Use BIT() macros for @flags values

2023-01-11T14:35:11Z

Rather than manually calculating powers of 2, use the BIT() macros. Also take this opportunatity to cleanup and restructure the value comments into proper kerneldoc comments. Signed-off-by: Thomas Gleixner Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20230109100800.1085541-3-john.ogness@linutronix.de

printk, xen: fbfront: create/use safe function for forcing preferred

2022-12-02T10:25:02Z

With commit 9e124fe16ff2("xen: Enable console tty by default in domU if it's not a dummy") a hack was implemented to make sure that the tty console remains the console behind the /dev/console device. The main problem with the hack is that, after getting the console pointer to the tty console, it is assumed the pointer is still valid after releasing the console_sem. This assumption is incorrect and unsafe. Make the hack safe by introducing a new function console_force_preferred_locked() and perform the full operation under the console_list_lock. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20221116162152.193147-33-john.ogness@linutronix.de

console: introduce console_is_registered()

2022-12-02T10:25:01Z

Currently it is not possible for drivers to detect if they have already successfully registered their console. Several drivers have multiple paths that lead to console registration. To avoid attempting a 2nd registration (which leads to a WARN), drivers are implementing their own solution. Introduce console_is_registered() so drivers can easily identify if their console is currently registered. A _locked() variant is also provided if the caller is already holding the console_list_lock. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20221116162152.193147-22-john.ogness@linutronix.de

console: introduce wrappers to read/write console flags

2022-12-02T10:25:00Z

After switching to SRCU for console list iteration, some readers will begin readings console->flags as a data race. Locklessly reading console->flags provides a consistent value because there is at most one CPU modifying console->flags and that CPU is using only read-modify-write operations. Introduce a wrapper for SRCU iterators to read console flags. Introduce a matching wrapper to write to flags of registered consoles. Writing to flags of registered consoles is synchronized by the console_list_lock. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20221116162152.193147-13-john.ogness@linutronix.de

printk: introduce console_list_lock

2022-12-02T10:25:00Z

Currently there exist races in register_console(), where the types of registered consoles are checked (without holding the console_lock) and then after acquiring the console_lock, it is assumed that the list has not changed. Also, some code that performs console_unregister() make similar assumptions. It might be possible to fix these races using the console_lock. But it would require a complex analysis of all console drivers to make sure that the console_lock is not taken in match() and setup() callbacks. And we really prefer to split up and reduce the responsibilities of console_lock rather than expand its complexity. Therefore, introduce a new console_list_lock to provide full synchronization for any console list changes. In addition, also use console_list_lock for synchronization of console->flags updates. All flags are either static or modified only during the console registration. There are only two exceptions. The first exception is CON_ENABLED, which is also modified by console_start()/console_stop(). Therefore, these functions must also take the console_list_lock. The second exception is when the flags are modified by the console driver init code before the console is registered. These will be ignored because they are not visible to the rest of the system via the console_drivers list. Note that one of the various responsibilities of the console_lock is also intended to provide console list and console->flags synchronization. Later changes will update call sites relying on the console_lock for these purposes. Once all call sites have been updated, the console_lock will be relieved of synchronizing console_list and console->flags updates. Suggested-by: Thomas Gleixner Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/87sficwokr.fsf@jogness.linutronix.de

printk: Prepare for SRCU console list protection

2022-12-02T10:24:59Z

Provide an NMI-safe SRCU protected variant to walk the console list. Note that all console fields are now set before adding the console to the list to avoid the console becoming visible by SCRU readers before being fully initialized. This is a preparatory change for a new console infrastructure which operates independent of the console BKL. Suggested-by: Thomas Gleixner Signed-off-by: John Ogness Acked-by: Miguel Ojeda Reviewed-by: Paul E. McKenney Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20221116162152.193147-4-john.ogness@linutronix.de