Pull s390 updates from Vasily Gorbik:
- Add sorting of mcount locations at build time
- Rework uaccess functions with C exception handling to shorten inline
assembly size and enable full inlining. This yields near-optimal code
for small constant copies with a ~40kb kernel size increase
- Add support for a configurable STRICT_MM_TYPECHECKS which allows to
generate better code, but also allows to have type checking for debug
builds
- Optimize get_lowcore() for common callers with alternatives that
nearly revert to the pre-relocated lowcore code, while also slightly
reducing syscall entry and exit time
- Convert MACHINE_HAS_* checks for single facility tests into cpu_has_*
style macros that call test_facility(), and for features with
additional conditions, add a new ALT_TYPE_FEATURE alternative to
provide a static branch via alternative patching. Also, move machine
feature detection to the decompressor for early patching and add
debugging functionality to easily show which alternatives are patched
- Add exception table support to early boot / startup code to get rid
of the open coded exception handling
- Use asm_inline for all inline assemblies with EX_TABLE or ALTERNATIVE
to ensure correct inlining and unrolling decisions
- Remove 2k page table leftovers now that s390 has been switched to
always allocate 4k page tables
- Split kfence pool into 4k mappings in arch_kfence_init_pool() and
remove the architecture-specific kfence_split_mapping()
- Use READ_ONCE_NOCHECK() in regs_get_kernel_stack_nth() to silence
spurious KASAN warnings from opportunistic ftrace argument tracing
- Force __atomic_add_const() variants on s390 to always return void,
ensuring compile errors for improper usage
- Remove s390's ioremap_wt() and pgprot_writethrough() due to
mismatched semantics and lack of known users, relying on asm-generic
fallbacks
- Signal eventfd in vfio-ap to notify userspace when the guest AP
configuration changes, including during mdev removal
- Convert mdev_types from an array to a pointer in vfio-ccw and vfio-ap
drivers to avoid fake flex array confusion
- Cleanup trap code
- Remove references to the outdated linux390@de.ibm.com address
- Other various small fixes and improvements all over the code
* tag 's390-6.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (78 commits)
s390: Use inline qualifier for all EX_TABLE and ALTERNATIVE inline assemblies
s390/kfence: Split kfence pool into 4k mappings in arch_kfence_init_pool()
s390/ptrace: Avoid KASAN false positives in regs_get_kernel_stack_nth()
s390/boot: Ignore vmlinux.map
s390/sysctl: Remove "vm/allocate_pgste" sysctl
s390: Remove 2k vs 4k page table leftovers
s390/tlb: Use mm_has_pgste() instead of mm_alloc_pgste()
s390/lowcore: Use lghi instead llilh to clear register
s390/syscall: Merge __do_syscall() and do_syscall()
s390/spinlock: Implement SPINLOCK_LOCKVAL with inline assembly
s390/smp: Implement raw_smp_processor_id() with inline assembly
s390/current: Implement current with inline assembly
s390/lowcore: Use inline qualifier for get_lowcore() inline assembly
s390: Move s390 sysctls into their own file under arch/s390
s390/syscall: Simplify syscall_get_arguments()
s390/vfio-ap: Notify userspace that guest's AP config changed when mdev removed
s390: Remove ioremap_wt() and pgprot_writethrough()
s390/mm: Add configurable STRICT_MM_TYPECHECKS
s390/mm: Convert pgste_val() into function
s390/mm: Convert pgprot_val() into function
...
Pull printk updates from Petr Mladek:
- New option "printk.debug_non_panic_cpus" allows to store printk
messages from non-panic CPUs during panic. It might be useful when
panic() fails. It is disabled by default because it increases the
chance to see the messages printed before panic() and on the
panic-CPU.
- New build option "CONFIG_NULL_TTY_DEFAULT_CONSOLE" allows to build
kernel without the virtual terminal support which prefers ttynull
over serial console.
- Do not unblank suspended consoles.
- Some code clean up.
* tag 'printk-for-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk/panic: Add option to allow non-panic CPUs to write to the ring buffer.
printk: Add an option to allow ttynull to be a default console device
printk: Check CON_SUSPEND when unblanking a console
printk: Rename console_start to console_resume
printk: Rename console_stop to console_suspend
printk: Rename resume_console to console_resume_all
printk: Rename suspend_console to console_suspend_all
The new option is CONFIG_NULL_TTY_DEFAULT_CONSOLE.
if enabled, and CONFIG_VT is disabled, ttynull will become the default
primary console device.
ttynull will be the only console device usually with this option enabled.
Some architectures do call add_preferred_console() which may add another
console though.
Motivation:
Many distributions ship with CONFIG_VT enabled. On tested desktop hardware
if CONFIG_VT is disabled, the default console device falls back to
/dev/ttyS0 instead of /dev/tty.
This could cause issues in user space, and hardware problems:
1. The user space issues include the case where /dev/ttyS0 is
disconnected, and the TCGETS ioctl, which some user space libraries use
as a probe to determine if a file is a tty, is called on /dev/console and
fails. Programs that call isatty() on /dev/console and get an incorrect
false value may skip expected logging to /dev/console.
2. The hardware issues include the case if a user has a science instrument
or other device connected to the /dev/ttyS0 port, and they were to upgrade
to a kernel that is disabling the CONFIG_VT option, kernel logs will then
be sent to the device connected to /dev/ttyS0 unless they edit their
kernel command line manually.
The new CONFIG_NULL_TTY_DEFAULT_CONSOLE option will give users and
distribution maintainers an option to avoid this. Disabling CONFIG_VT and
enabling CONFIG_NULL_TTY_DEFAULT_CONSOLE will ensure the default kernel
console behavior is not dependent on hardware configuration by default, and
avoid unexpected new behavior on devices connected to the /dev/ttyS0 serial
port.
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Adam Simonelli <adamsimonelli@gmail.com>
Link: https://lore.kernel.org/r/20250314160749.3286153-2-adamsimonelli@gmail.com
[pmladek@suse.com: Fixed indentation of the commit message.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
Move machine type detection to the decompressor and use static branches
to implement and use machine_is_[lpar|vm|kvm]() instead of a runtime check
via MACHINE_IS_[LPAR|VM|KVM].
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Pull serial driver fixes from Greg KH:
"Here are some small serial driver fixes for some reported problems.
Nothing major, just:
- sc16is7xx irq check fix
- 8250 fifo underflow fix
- serial_port and 8250 iotype fixes
Most of these have been in linux-next already, and all have passed
0-day testing"
* tag 'tty-6.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
serial: 8250: Fix fifo underflow on flush
serial: 8250_pnp: Remove unneeded ->iotype assignment
serial: 8250_platform: Remove unneeded ->iotype assignment
serial: 8250_of: Remove unneeded ->iotype assignment
serial: port: Make ->iotype validation global in __uart_read_properties()
serial: port: Always update ->iotype in __uart_read_properties()
serial: port: Assign ->iotype correctly when ->iobase is set
serial: sc16is7xx: Fix IRQ number check behavior
When flushing the serial port's buffer, uart_flush_buffer() calls
kfifo_reset() but if there is an outstanding DMA transfer then the
completion function will consume data from the kfifo via
uart_xmit_advance(), underflowing and leading to ongoing DMA as the
driver tries to transmit another 2^32 bytes.
This is readily reproduced with serial-generic and amidi sending even
short messages as closing the device on exit will wait for the fifo to
drain and in the underflow case amidi hangs for 30 seconds on exit in
tty_wait_until_sent(). A trace of that gives:
kworker/1:1-84 [001] 51.769423: bprint: serial8250_tx_dma: tx_size=3 fifo_len=3
amidi-763 [001] 51.769460: bprint: uart_flush_buffer: resetting fifo
irq/21-fe530000-76 [000] 51.769474: bprint: __dma_tx_complete: tx_size=3
irq/21-fe530000-76 [000] 51.769479: bprint: serial8250_tx_dma: tx_size=4096 fifo_len=4294967293
irq/21-fe530000-76 [000] 51.781295: bprint: __dma_tx_complete: tx_size=4096
irq/21-fe530000-76 [000] 51.781301: bprint: serial8250_tx_dma: tx_size=4096 fifo_len=4294963197
irq/21-fe530000-76 [000] 51.793131: bprint: __dma_tx_complete: tx_size=4096
irq/21-fe530000-76 [000] 51.793135: bprint: serial8250_tx_dma: tx_size=4096 fifo_len=4294959101
irq/21-fe530000-76 [000] 51.804949: bprint: __dma_tx_complete: tx_size=4096
Since the port lock is held in when the kfifo is reset in
uart_flush_buffer() and in __dma_tx_complete(), adding a flush_buffer
hook to adjust the outstanding DMA byte count is sufficient to avoid the
kfifo underflow.
Fixes: 9ee4b83e51 ("serial: 8250: Add support for dmaengine")
Cc: stable <stable@kernel.org>
Signed-off-by: John Keeping <jkeeping@inmusicbrands.com>
Link: https://lore.kernel.org/r/20250208124148.1189191-1-jkeeping@inmusicbrands.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The FMODE_NONOTIFY_* bits are a 2-bits mode. Open coding manipulation
of those bits is risky. Use an accessor file_set_fsnotify_mode() to
set the mode.
Rename file_set_fsnotify_mode() => file_set_fsnotify_mode_from_watchers()
to make way for the simple accessor name.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20250203223205.861346-2-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
The documentation of the __uart_read_properties() states that
->iotype member is always altered after the function call, but
the code doesn't do that in the case when use_defaults == false
and the value of reg-io-width is unsupported. Make sure the code
follows the documentation.
Note, the current users of the uart_read_and_validate_port_properties()
will fail and the change doesn't affect their behaviour, neither
users of uart_read_port_properties() will be affected since the
alteration happens there even in the current code flow.
Fixes: e894b6005d ("serial: port: Introduce a common helper to read properties")
Cc: stable <stable@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250124161530.398361-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull driver core and debugfs updates from Greg KH:
"Here is the big set of driver core and debugfs updates for 6.14-rc1.
Included in here is a bunch of driver core, PCI, OF, and platform rust
bindings (all acked by the different subsystem maintainers), hence the
merge conflict with the rust tree, and some driver core api updates to
mark things as const, which will also require some fixups due to new
stuff coming in through other trees in this merge window.
There are also a bunch of debugfs updates from Al, and there is at
least one user that does have a regression with these, but Al is
working on tracking down the fix for it. In my use (and everyone
else's linux-next use), it does not seem like a big issue at the
moment.
Here's a short list of the things in here:
- driver core rust bindings for PCI, platform, OF, and some i/o
functions.
We are almost at the "write a real driver in rust" stage now,
depending on what you want to do.
- misc device rust bindings and a sample driver to show how to use
them
- debugfs cleanups in the fs as well as the users of the fs api for
places where drivers got it wrong or were unnecessarily doing
things in complex ways.
- driver core const work, making more of the api take const * for
different parameters to make the rust bindings easier overall.
- other small fixes and updates
All of these have been in linux-next with all of the aforementioned
merge conflicts, and the one debugfs issue, which looks to be resolved
"soon""
* tag 'driver-core-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (95 commits)
rust: device: Use as_char_ptr() to avoid explicit cast
rust: device: Replace CString with CStr in property_present()
devcoredump: Constify 'struct bin_attribute'
devcoredump: Define 'struct bin_attribute' through macro
rust: device: Add property_present()
saner replacement for debugfs_rename()
orangefs-debugfs: don't mess with ->d_name
octeontx2: don't mess with ->d_parent or ->d_parent->d_name
arm_scmi: don't mess with ->d_parent->d_name
slub: don't mess with ->d_name
sof-client-ipc-flood-test: don't mess with ->d_name
qat: don't mess with ->d_name
xhci: don't mess with ->d_iname
mtu3: don't mess wiht ->d_iname
greybus/camera - stop messing with ->d_iname
mediatek: stop messing with ->d_iname
netdevsim: don't embed file_operations into your structs
b43legacy: make use of debugfs_get_aux()
b43: stop embedding struct file_operations into their objects
carl9170: stop embedding file_operations into their objects
...
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
...
Pull non-MM updates from Andrew Morton:
"Mainly individually changelogged singleton patches. The patch series
in this pull are:
- "lib min_heap: Improve min_heap safety, testing, and documentation"
from Kuan-Wei Chiu provides various tightenings to the min_heap
library code
- "xarray: extract __xa_cmpxchg_raw" from Tamir Duberstein preforms
some cleanup and Rust preparation in the xarray library code
- "Update reference to include/asm-<arch>" from Geert Uytterhoeven
fixes pathnames in some code comments
- "Converge on using secs_to_jiffies()" from Easwar Hariharan uses
the new secs_to_jiffies() in various places where that is
appropriate
- "ocfs2, dlmfs: convert to the new mount API" from Eric Sandeen
switches two filesystems to the new mount API
- "Convert ocfs2 to use folios" from Matthew Wilcox does that
- "Remove get_task_comm() and print task comm directly" from Yafang
Shao removes now-unneeded calls to get_task_comm() in various
places
- "squashfs: reduce memory usage and update docs" from Phillip
Lougher implements some memory savings in squashfs and performs
some maintainability work
- "lib: clarify comparison function requirements" from Kuan-Wei Chiu
tightens the sort code's behaviour and adds some maintenance work
- "nilfs2: protect busy buffer heads from being force-cleared" from
Ryusuke Konishi fixes an issues in nlifs when the fs is presented
with a corrupted image
- "nilfs2: fix kernel-doc comments for function return values" from
Ryusuke Konishi fixes some nilfs kerneldoc
- "nilfs2: fix issues with rename operations" from Ryusuke Konishi
addresses some nilfs BUG_ONs which syzbot was able to trigger
- "minmax.h: Cleanups and minor optimisations" from David Laight does
some maintenance work on the min/max library code
- "Fixes and cleanups to xarray" from Kemeng Shi does maintenance
work on the xarray library code"
* tag 'mm-nonmm-stable-2025-01-24-23-16' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (131 commits)
ocfs2: use str_yes_no() and str_no_yes() helper functions
include/linux/lz4.h: add some missing macros
Xarray: use xa_mark_t in xas_squash_marks() to keep code consistent
Xarray: remove repeat check in xas_squash_marks()
Xarray: distinguish large entries correctly in xas_split_alloc()
Xarray: move forward index correctly in xas_pause()
Xarray: do not return sibling entries from xas_find_marked()
ipc/util.c: complete the kernel-doc function descriptions
gcov: clang: use correct function param names
latencytop: use correct kernel-doc format for func params
minmax.h: remove some #defines that are only expanded once
minmax.h: simplify the variants of clamp()
minmax.h: move all the clamp() definitions after the min/max() ones
minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()
minmax.h: reduce the #define expansion of min(), max() and clamp()
minmax.h: update some comments
minmax.h: add whitespace around operators and after commas
nilfs2: do not update mtime of renamed directory that is not moved
nilfs2: handle errors that nilfs_prepare_chunk() may return
CREDITS: fix spelling mistake
...
In the sh-sci driver, serial ports are mapped to the sci_ports[] array,
with earlycon mapped at index zero.
The uart_add_one_port() function eventually calls __device_attach(),
which, in turn, calls pm_request_idle(). The identified code path is as
follows:
uart_add_one_port() ->
serial_ctrl_register_port() ->
serial_core_register_port() ->
serial_core_port_device_add() ->
serial_base_port_add() ->
device_add() ->
bus_probe_device() ->
device_initial_probe() ->
__device_attach() ->
// ...
if (dev->p->dead) {
// ...
} else if (dev->driver) {
// ...
} else {
// ...
pm_request_idle(dev);
// ...
}
The earlycon device clocks are enabled by the bootloader. However, the
pm_request_idle() call in __device_attach() disables the SCI port clocks
while earlycon is still active.
The earlycon write function, serial_console_write(), calls
sci_poll_put_char() via serial_console_putchar(). If the SCI port clocks
are disabled, writing to earlycon may sometimes cause the SR.TDFE bit to
remain unset indefinitely, causing the while loop in sci_poll_put_char()
to never exit. On single-core SoCs, this can result in the system being
blocked during boot when this issue occurs.
To resolve this, increment the runtime PM usage counter for the earlycon
SCI device before registering the UART port.
Fixes: 0b0cced19a ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable@vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://lore.kernel.org/r/20250116182249.3828577-6-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The early_console_setup() function initializes sci_ports[0].port with an
object of type struct uart_port obtained from the struct earlycon_device
passed as an argument to early_console_setup().
Later, during serial port probing, the serial port used as earlycon
(e.g., port A) might be remapped to a different position in the sci_ports[]
array, and a different serial port (e.g., port B) might be assigned to slot
0. For example:
sci_ports[0] = port B
sci_ports[X] = port A
In this scenario, the new port mapped at index zero (port B) retains the
data associated with the earlycon configuration. Consequently, after the
Linux boot process, any access to the serial port now mapped to
sci_ports[0] (port B) will block the original earlycon port (port A).
To address this, introduce an early_console_exit() function to clean up
sci_ports[0] when earlycon is exited.
To prevent the cleanup of sci_ports[0] while the serial device is still
being used by earlycon, introduce the struct sci_port::probing flag and
account for it in early_console_exit().
Fixes: 0b0cced19a ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable@vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://lore.kernel.org/r/20250116182249.3828577-5-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kgdb_nmi_poll_knock() has been unused since it was added in 2013 in
commit 0c57dfcc6c ("tty/serial: Add kgdb_nmi driver")
Remove it, the static helpers, and module parameters it used.
(The comment explaining why it might be used sounds sensible, but
it's never been wired up, perhaps it's worth doing somewhere?)
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://lore.kernel.org/r/20250112135759.105541-1-linux@treblig.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
With this, processes without CAP_SYS_ADMIN are able to use TIOCLINUX with
subcode TIOCL_SETSEL, in the selection modes TIOCL_SETPOINTER,
TIOCL_SELCLEAR and TIOCL_SELMOUSEREPORT.
TIOCL_SETSEL was previously changed to require CAP_SYS_ADMIN, as this IOCTL
let callers change the selection buffer and could be used to simulate
keypresses. These three TIOCL_SETSEL selection modes, however, are safe to
use, as they do not modify the selection buffer.
This fixes a mouse support regression that affected Emacs (invisible mouse
cursor).
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/ee3ec63269b43b34e1c90dd8c9743bf8@finder.org
Fixes: 8d1b43f6a6 ("tty: Restrict access to TIOCLINUX' copy-and-paste subcommands")
Signed-off-by: Günther Noack <gnoack@google.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/r/20250110142122.1013222-1-gnoack@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
lockdep detects the following circular locking dependency:
CPU 0 CPU 1
========================== ============================
cdns_uart_isr() printk()
uart_port_lock(port) console_lock()
cdns_uart_console_write()
if (!port->sysrq)
uart_port_lock(port)
uart_handle_break()
port->sysrq = ...
uart_handle_sysrq_char()
printk()
console_lock()
The fixed commit attempts to avoid this situation by only taking the
port lock in cdns_uart_console_write if port->sysrq unset. However, if
(as shown above) cdns_uart_console_write runs before port->sysrq is set,
then it will try to take the port lock anyway. This may result in a
deadlock.
Fix this by splitting sysrq handling into two parts. We use the prepare
helper under the port lock and defer handling until we release the lock.
Fixes: 74ea66d4ca ("tty: xuartps: Improve sysrq handling")
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Cc: stable@vger.kernel.org # c980248179: serial: xilinx_uartps: Use port lock wrappers
Acked-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/r/20250110213822.2107462-1-sean.anderson@linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need the debugfs / driver-core fixes in here as well for testing and
to build on top of.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Implement the necessary callbacks to switch the 8250 console driver
to perform as an nbcon console.
Add implementations for the nbcon console callbacks:
->write_atomic()
->write_thread()
->device_lock()
->device_unlock()
and add CON_NBCON to the initial @flags.
All register access in the callbacks are within unsafe sections.
The ->write_atomic() and ->write_thread() callbacks allow safe
handover/takeover per byte and add a preceding newline if they
take over from another context mid-line.
For the ->write_atomic() callback, a new irq_work is used to defer
modem control since it may be called from a context that does not
allow waking up tasks.
Note: A new __serial8250_clear_IER() is introduced for direct
clearing of UART_IER. This will allow to restore the lockdep
check to serial8250_clear_IER() in a follow-up commit.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20250107212702.169493-6-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For RS485 mode, if SER_RS485_RX_DURING_TX is not available, the
console ->write() callback needs to enable/disable Tx. It does
this by calling the ->rs485_start_tx() and ->rs485_stop_tx()
callbacks. However, some of these callbacks also disable/enable
interrupts and makes power management calls. This causes 2
problems for console writing:
1. A console write can occur in contexts that are illegal for
pm_runtime_*(). It is not even necessary for console writing
to use pm_runtime_*() because a console already does this in
serial8250_console_setup() and serial8250_console_exit().
2. The console ->write() callback already handles
disabling/enabling the interrupts by properly restoring the
previous IER value.
Add an argument @toggle_ier to the ->rs485_start_tx() and
->rs485_stop_tx() callbacks to specify if they may disable/enable
receive interrupts while using pm_runtime_*(). Console writing
will not allow the toggling.
For all call sites other than console writing there is no
functional change.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20250107212702.169493-5-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently serial8250_console_fifo_write() directly writes into
the UART_TX register rather than using the high-level function
serial8250_console_putchar(). This is because
serial8250_console_putchar() waits for the holding register to
become empty, which would defeat the purpose of the FIFO code.
Move the LSR_THRE waiting to a new function
serial8250_console_wait_putchar() so that the FIFO code can use
serial8250_console_putchar(). This will be particularly important
for a follow-up commit, where output bytes are inspected to track
newlines.
This is only refactoring and has no functional change.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20250107212702.169493-4-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
After a console has written a record into UART_TX, it uses
wait_for_xmitr() to wait until the data has been sent out before
returning. However, wait_for_xmitr() will timeout after 10ms,
regardless if the data has been transmitted or not.
For single bytes, this timeout is sufficient even at very slow
baud rates, such as 1200bps. However, when FIFO mode is used,
there may be 64 bytes pushed into the FIFO at once. At a baud
rate of 115200bps, the 10ms timeout is still sufficient. But
when using lower baud rates (such as 57600bps), the timeout
is _not_ sufficient. This causes longer lines to be cut off,
resulting in lost and horribly misformatted output on the
console.
When using FIFO mode, take the number of bytes into account to
determine an appropriate maximum timeout. Increasing the timeout
does not affect performance since ideally the timeout never
occurs.
Fixes: 8f3631f0f6 ("serial/8250: Use fifo in 8250 console driver")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Wander Lairson Costa <wander@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20250107212702.169493-2-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, code retries n2 times to open control dlci in ABM mode before
switching to ADM mode, but only if DM has been received. This contradicts
to the comment that dlci is switched to control mode unconditionally if
DLCI_OPENING retries time out. Also, it does not make sense to continue
trying once DM has received.
Change the logic to switch to ADM mode upon DM received. That way control
channel state will change to DLCI_OPEN way faster. Fix the misleading
comment while at it.
Signed-off-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20241228150100.100354-3-ivo.g.dimitrov.75@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
