commit 59ff0680ec upstream.
The current implementation constipates all transmission paths during flow
control except for flow control frames. However, these may not be located
at the beginning of the transmission queue of the control channel.
Ensure that flow control frames in the transmission queue for the control
channel are always handled even if constipated by skipping through other
messages.
Fixes: 0af021678d ("tty: n_gsm: fix deadlock and link starvation in outgoing data path")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220707113223.3685-3-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 0af021678d ]
The current implementation queues up new control and user packets as needed
and processes this queue down to the ldisc in the same code path.
That means that the upper and the lower layer are hard coupled in the code.
Due to this deadlocks can happen as seen below while transmitting data,
especially during ldisc congestion. Furthermore, the data channels starve
the control channel on high transmission load on the ldisc.
Introduce an additional control channel data queue to prevent timeouts and
link hangups during ldisc congestion. This is being processed before the
user channel data queue in gsm_data_kick(), i.e. with the highest priority.
Put the queue to ldisc data path into a workqueue and trigger it whenever
new data has been put into the transmission queue. Change
gsm_dlci_data_sweep() accordingly to fill up the transmission queue until
TX_THRESH_HI. This solves the locking issue, keeps latency low and provides
good performance on high data load.
Note that now all packets from a DLCI are removed from the internal queue
if the associated DLCI was closed. This ensures that no data is sent by the
introduced write task to an already closed DLCI.
BUG: spinlock recursion on CPU#0, test_v24_loop/124
lock: serial8250_ports+0x3a8/0x7500, .magic: dead4ead, .owner: test_v24_loop/124, .owner_cpu: 0
CPU: 0 PID: 124 Comm: test_v24_loop Tainted: G O 5.18.0-rc2 #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Call Trace:
<IRQ>
dump_stack_lvl+0x34/0x44
do_raw_spin_lock+0x76/0xa0
_raw_spin_lock_irqsave+0x72/0x80
uart_write_room+0x3b/0xc0
gsm_data_kick+0x14b/0x240 [n_gsm]
gsmld_write_wakeup+0x35/0x70 [n_gsm]
tty_wakeup+0x53/0x60
tty_port_default_wakeup+0x1b/0x30
serial8250_tx_chars+0x12f/0x220
serial8250_handle_irq.part.0+0xfe/0x150
serial8250_default_handle_irq+0x48/0x80
serial8250_interrupt+0x56/0xa0
__handle_irq_event_percpu+0x78/0x1f0
handle_irq_event+0x34/0x70
handle_fasteoi_irq+0x90/0x1e0
__common_interrupt+0x69/0x100
common_interrupt+0x48/0xc0
asm_common_interrupt+0x1e/0x40
RIP: 0010:__do_softirq+0x83/0x34e
Code: 2a 0a ff 0f b7 ed c7 44 24 10 0a 00 00 00 48 c7 c7 51 2a 64 82 e8 2d
e2 d5 ff 65 66 c7 05 83 af 1e 7e 00 00 fb b8 ff ff ff ff <49> c7 c2 40 61
80 82 0f bc c5 41 89 c4 41 83 c4 01 0f 84 e6 00 00
RSP: 0018:ffffc90000003f98 EFLAGS: 00000286
RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff82642a51 RDI: ffffffff825bb5e7
RBP: 0000000000000200 R08: 00000008de3271a8 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000030 R14: 0000000000000000 R15: 0000000000000000
? __do_softirq+0x73/0x34e
irq_exit_rcu+0xb5/0x100
common_interrupt+0xa4/0xc0
</IRQ>
<TASK>
asm_common_interrupt+0x1e/0x40
RIP: 0010:_raw_spin_unlock_irqrestore+0x2e/0x50
Code: 00 55 48 89 fd 48 83 c7 18 53 48 89 f3 48 8b 74 24 10 e8 85 28 36 ff
48 89 ef e8 cd 58 36 ff 80 e7 02 74 01 fb bf 01 00 00 00 <e8> 3d 97 33 ff
65 8b 05 96 23 2b 7e 85 c0 74 03 5b 5d c3 0f 1f 44
RSP: 0018:ffffc9000020fd08 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 0000000000000246 RCX: 0000000000000000
RDX: 0000000000000004 RSI: ffffffff8257fd74 RDI: 0000000000000001
RBP: ffff8880057de3a0 R08: 00000008de233000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000100 R14: 0000000000000202 R15: ffff8880057df0b8
? _raw_spin_unlock_irqrestore+0x23/0x50
gsmtty_write+0x65/0x80 [n_gsm]
n_tty_write+0x33f/0x530
? swake_up_all+0xe0/0xe0
file_tty_write.constprop.0+0x1b1/0x320
? n_tty_flush_buffer+0xb0/0xb0
new_sync_write+0x10c/0x190
vfs_write+0x282/0x310
ksys_write+0x68/0xe0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f3e5e35c15c
Code: 8b 7c 24 08 89 c5 e8 c5 ff ff ff 89 ef 89 44 24 08 e8 58 bc 02 00 8b
44 24 08 48 83 c4 10 5d c3 48 63 ff b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff
ff 76 10 48 8b 15 fd fc 05 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffcee77cd18 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffcee77cd70 RCX: 00007f3e5e35c15c
RDX: 0000000000000100 RSI: 00007ffcee77cd90 RDI: 0000000000000003
RBP: 0000000000000100 R08: 0000000000000000 R09: 7efefefefefefeff
R10: 00007f3e5e3bddeb R11: 0000000000000246 R12: 00007ffcee77ce8f
R13: 0000000000000001 R14: 000056214404e010 R15: 00007ffcee77cd90
</TASK>
Fixes: e1eaea46bb ("tty: n_gsm line discipline")
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220701122332.2039-1-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ The context change is due to the commit a8c5b8255f
("tty: n_gsm: fix broken virtual tty handling") in v5.18
which is irrelevant to the logic of this patch. ]
Signed-off-by: Johnny Hao <johnny_haocn@sina.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d54801cd50 upstream.
ulite_probe() calls pm_runtime_put_autosuspend() at the end of probe
without holding a corresponding PM runtime reference for non-console
ports.
During ulite_assign(), uart_add_one_port() triggers uart_configure_port()
which calls ulite_pm() via uart_change_pm(). For non-console ports, the
UART core performs a balanced get/put cycle:
uart_change_pm(ON) -> ulite_pm() -> pm_runtime_get_sync() +1
uart_change_pm(OFF) -> ulite_pm() -> pm_runtime_put_autosuspend() -1
This leaves no spare reference for the pm_runtime_put_autosuspend() at
the end of probe. The PM runtime core prevents the count from actually
going below zero, and instead triggers a
"Runtime PM usage count underflow!" warning.
For console ports the bug is masked: the UART core skips the
uart_change_pm(OFF) call, so the UART core's unbalanced get happens to
pair with probe's trailing put.
Add pm_runtime_get_noresume() before pm_runtime_enable() to take an
explicit probe-owned reference that the trailing
pm_runtime_put_autosuspend() can release. This ensures a correct usage
count regardless of whether the port is a console.
Fixes: 5bbe10a694 ("tty: serial: uartlite: Add runtime pm support")
Cc: stable <stable@kernel.org>
Signed-off-by: Maciej Andrzejewski ICEYE <maciej.andrzejewski@m-works.net>
Link: https://patch.msgid.link/20260305123746.4152800-1-maciej.andrzejewski@m-works.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e0a368ae79 upstream.
When DW UART is !uart_16550_compatible, it can indicate BUSY at any
point (when under constant Rx pressure) unless a complex sequence of
steps is performed. Any LCR write can run a foul with the condition
that prevents writing LCR while the UART is BUSY, which triggers
BUSY_DETECT interrupt that seems unmaskable using IER bits.
Normal flow is that dw8250_handle_irq() handles BUSY_DETECT condition
by reading USR register. This BUSY feature, however, breaks the
assumptions made in serial8250_do_shutdown(), which runs
synchronize_irq() after clearing IER and assumes no interrupts can
occur after that point but then proceeds to update LCR, which on DW
UART can trigger an interrupt.
If serial8250_do_shutdown() releases the interrupt handler before the
handler has run and processed the BUSY_DETECT condition by read the USR
register, the IRQ is not deasserted resulting in interrupt storm that
triggers "irq x: nobody cared" warning leading to disabling the IRQ.
Add late synchronize_irq() into serial8250_do_shutdown() to ensure
BUSY_DETECT from DW UART is handled before port's interrupt handler is
released. Alternative would be to add DW UART specific shutdown
function but it would mostly duplicate the generic code and the extra
synchronize_irq() seems pretty harmless in serial8250_do_shutdown().
Fixes: 7d4008ebb1 ("tty: add a DesignWare 8250 driver")
Cc: stable <stable@kernel.org>
Reported-by: Bandal, Shankar <shankar.bandal@intel.com>
Tested-by: Bandal, Shankar <shankar.bandal@intel.com>
Tested-by: Murthy, Shanth <shanth.murthy@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20260203171049.4353-7-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a424a34b8f upstream.
`dmaengine_terminate_async` does not guarantee that the
`__dma_tx_complete` callback will run. The callback is currently the
only place where `dma->tx_running` gets cleared. If the transaction is
canceled and the callback never runs, then `dma->tx_running` will never
get cleared and we will never schedule new TX DMA transactions again.
This change makes it so we clear `dma->tx_running` after we terminate
the DMA transaction. This is "safe" because `serial8250_tx_dma_flush`
is holding the UART port lock. The first thing the callback does is also
grab the UART port lock, so access to `dma->tx_running` is serialized.
Fixes: 9e512eaaf8 ("serial: 8250: Fix fifo underflow on flush")
Cc: stable <stable@kernel.org>
Signed-off-by: Raul E Rangel <rrangel@google.com>
Link: https://patch.msgid.link/20260209135815.1.I16366ecb0f62f3c96fe3dd5763fcf6f3c2b4d8cd@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9c0072bc33 upstream.
This is found in popular brands such as StarTech.com or Delock, and has
been a source of frustration to quite a few people, if I can trust
Amazon comments complaining about Linux support via the official
out-of-the-tree driver.
Signed-off-by: Martin Roukala (né Peres) <martin.roukala@mupuf.org>
Cc: stable <stable@kernel.org>
Link: https://patch.msgid.link/20260309-8250_pci_ax99100-v1-1-3328bdfd8e94@mupuf.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit a5fd8945a4 ]
Clear rx_running flag only after DMA teardown polling completes. In the
previous implementation the flag was being cleared while hardware teardown
was still in progress, creating a mismatch between software state
(flag = 0, "ready") and hardware state (still terminating).
Signed-off-by: Moteen Shah <m-shah@ti.com>
Link: https://patch.msgid.link/20260112081829.63049-3-m-shah@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d31228143a ]
Add error checking for clk_prepare_enable() calls in
dw8250_runtime_resume(). Currently if either clock fails to enable,
the function returns success while leaving clocks in inconsistent state.
This change implements comprehensive error handling by checking the return
values of both clk_prepare_enable() calls. If the second clock enable
operation fails after the first clock has already been successfully
enabled, the code now properly cleans up by disabling and unpreparing
the first clock before returning. The error code is then propagated to
the caller, ensuring that clock enable failures are properly reported
rather than being silently ignored.
Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com>
Link: https://patch.msgid.link/20251104145433.2316165-2-a.shimko.dev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 93bb95a112 ]
Having a prompt of "DMA support" suddenly appear during a
"make oldconfig" can be confusing. Add a little helpful text to
the prompt message.
Fixes: 73a19e4c03 ("serial: sh-sci: Add DMA support.")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260110232643.3533351-5-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 79527d86ba ]
SERIAL_IMX_CONSOLE is a build option for the imx driver (SERIAL_IMX).
It does not build a separate console driver file, so it can't be built
as a module since it isn't built at all.
Change the Kconfig symbol from tristate to bool and update the help
text accordingly.
Fixes: 0db4f9b91c ("tty: serial: imx: enable imx serial console port as module")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://patch.msgid.link/20260110232643.3533351-2-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 29e8a0c587 ]
In sprd_clk_init(), when devm_clk_get() returns -EPROBE_DEFER
for either uart or source clock, we should propagate the
error instead of just warning and continuing with NULL clocks.
Currently the driver only emits a warning when clock acquisition
fails and proceeds with NULL clock pointers. This can lead to
issues later when the clocks are actually needed. More importantly,
when the clock provider is not ready yet and returns -EPROBE_DEFER,
we should return this error to allow deferred probing.
This change adds explicit checks for -EPROBE_DEFER after both:
1. devm_clk_get(uport->dev, uart)
2. devm_clk_get(uport->dev, source)
When -EPROBE_DEFER is encountered, the function now returns
-EPROBE_DEFER to let the driver framework retry probing
later when the clock dependencies are resolved.
Signed-off-by: Wenhua Lin <Wenhua.Lin@unisoc.com>
Link: https://patch.msgid.link/20251022030840.956589-1-Wenhua.Lin@unisoc.com
Reviewed-by: Cixi Geng <cixi.geng@linux.dev>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 0e5a99e0e5 upstream.
Addi-Data GmbH is manufacturing multi-serial ports cards supporting CompactPCI (known as CPCI).
Those cards are identified with different DeviceIds. Those cards integrating standard UARTs
work the same way as PCI/PCIe models already supported in the serial driver.
Signed-off-by: Magne Bruno <magne.bruno@addi-data.com>
Link: https://patch.msgid.link/20251110162456.341029-1-magne.bruno@addi-data.com
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit eb4917f557 upstream.
Check for returned DMA addresses using specialized dma_mapping_error()
helper which is generally recommended for this purpose by
Documentation/core-api/dma-api.rst:
"In some circumstances dma_map_single(), ...
will fail to create a mapping. A driver can check for these errors
by testing the returned DMA address with dma_mapping_error()."
Found via static analysis and this is similar to commit fa0308134d
("ALSA: memalloc: prefer dma_mapping_error() over explicit address checking")
Fixes: 58ac1b3799 ("ARM: PL011: Fix DMA support")
Cc: stable <stable@kernel.org>
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://patch.msgid.link/20251027092053.87937-1-linmq006@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit daeb4037ad ]
Check the return value of reset_control_deassert() in the probe
function to prevent continuing probe when reset deassertion fails.
Previously, reset_control_deassert() was called without checking its
return value, which could lead to probe continuing even when the
device reset wasn't properly deasserted.
The fix checks the return value and returns an error with dev_err_probe()
if reset deassertion fails, providing better error handling and
diagnostics.
Fixes: acbdad8dd1 ("serial: 8250_dw: simplify optional reset handling")
Cc: stable <stable@kernel.org>
Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com>
Link: https://patch.msgid.link/20251019095131.252848-1-a.shimko.dev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 295b09128d ]
Slightly simplify ->probe() and drop a few goto labels by using
devm_add_action_or_reset() for clock and reset cleanup.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220509172129.37770-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: daeb4037ad ("serial: 8250_dw: handle reset control deassert error")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e7cbce761f upstream.
The Advantech 2-port serial card with PCI vendor=0x13fe and device=0x0018
has a 'XR17V35X' chip installed on the circuit board. Therefore, this
driver can be used instead of theu outdated out-of-tree driver from the
manufacturer.
Signed-off-by: Florian Eckert <fe@dev.tdt.de>
Cc: stable <stable@kernel.org>
Link: https://patch.msgid.link/20250924134115.2667650-1-fe@dev.tdt.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 535fd4c984 ]
When trying to set MCR[2], XON1 is incorrectly accessed instead. And when
writing to the TCR register to configure flow control levels, we are
incorrectly writing to the MSR register. The default value of $00 is then
used for TCR, which means that selectable trigger levels in FCR are used
in place of TCR.
TCR/TLR access requires EFR[4] (enable enhanced functions) and MCR[2]
to be set. EFR[4] is already set in probe().
MCR access requires LCR[7] to be zero.
Since LCR is set to $BF when trying to set MCR[2], XON1 is incorrectly
accessed instead because MCR shares the same address space as XON1.
Since MCR[2] is unmodified and still zero, when writing to TCR we are in
fact writing to MSR because TCR/TLR registers share the same address space
as MSR/SPR.
Fix by first removing useless reconfiguration of EFR[4] (enable enhanced
functions), as it is already enabled in sc16is7xx_probe() since commit
43c51bb573 ("sc16is7xx: make sure device is in suspend once probed").
Now LCR is $00, which means that MCR access is enabled.
Also remove regcache_cache_bypass() calls since we no longer access the
enhanced registers set, and TCR is already declared as volatile (in fact
by declaring MSR as volatile, which shares the same address).
Finally disable access to TCR/TLR registers after modifying them by
clearing MCR[2].
Note: the comment about "... and internal clock div" is wrong and can be
ignored/removed as access to internal clock div registers (DLL/DLH)
is permitted only when LCR[7] is logic 1, not when enhanced features
is enabled. And DLL/DLH access is not needed in sc16is7xx_startup().
Fixes: dfeae619d7 ("serial: sc16is7xx")
Cc: stable@vger.kernel.org
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20250731124451.1108864-1-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ changed regmap variable from one->regmap to s->regmap ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit cfd956dcb1 upstream.
After hvc_write completes, call hvc_kick also in the case the output
buffer has been drained, to ensure tty_wakeup gets called.
This fixes that functions which wait for a drained buffer got stuck
occasionally.
Cc: stable <stable@kernel.org>
Closes: https://bugzilla.opensuse.org/show_bug.cgi?id=1230062
Signed-off-by: Fabian Vogt <fvogt@suse.de>
Link: https://lore.kernel.org/r/2011735.PYKUYFuaPT@fvogt-thinkpad
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b43cb4ff85 upstream.
The maximum number of keycodes got bumped to 256 a very long time ago,
but the default keymaps were never adjusted to match. This is causing
the kernel to interpret keycodes above 127 as U+0000 if the shipped
generated keymap is used.
Fix this by mapping all keycodes above 127 to K_HOLE so the kernel
ignores them.
The contents of this patche were generated by rerunning `loadkeys
--mktable --unicode` and only including the changes to map keycodes
above 127 to K_HOLE.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Myrrh Periwinkle <myrrhperiwinkle@qtmlabs.xyz>
Cc: stable <stable@kernel.org>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250702-vt-misc-unicode-fixes-v1-2-c27e143cc2eb@qtmlabs.xyz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b1cc2092ea upstream.
We don't process Unicode characters if the virtual terminal is in raw
mode, so there's no reason why we shouldn't do the same for K_OFF
(especially since people would expect K_OFF to actually turn off all VT
key processing).
Fixes: 9fc3de9c83 ("vt: Add virtual console keyboard mode OFF")
Signed-off-by: Myrrh Periwinkle <myrrhperiwinkle@qtmlabs.xyz>
Cc: stable <stable@kernel.org>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250702-vt-misc-unicode-fixes-v1-1-c27e143cc2eb@qtmlabs.xyz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7f8fdd4dbf upstream.
When the PSLVERR_RESP_EN parameter is set to 1, the device generates
an error response if an attempt is made to read an empty RBR (Receive
Buffer Register) while the FIFO is enabled.
In serial8250_do_startup(), calling serial_port_out(port, UART_LCR,
UART_LCR_WLEN8) triggers dw8250_check_lcr(), which invokes
dw8250_force_idle() and serial8250_clear_and_reinit_fifos(). The latter
function enables the FIFO via serial_out(p, UART_FCR, p->fcr).
Execution proceeds to the serial_port_in(port, UART_RX).
This satisfies the PSLVERR trigger condition.
When another CPU (e.g., using printk()) is accessing the UART (UART
is busy), the current CPU fails the check (value & ~UART_LCR_SPAR) ==
(lcr & ~UART_LCR_SPAR) in dw8250_check_lcr(), causing it to enter
dw8250_force_idle().
Put serial_port_out(port, UART_LCR, UART_LCR_WLEN8) under the port->lock
to fix this issue.
Panic backtrace:
[ 0.442336] Oops - unknown exception [#1]
[ 0.442343] epc : dw8250_serial_in32+0x1e/0x4a
[ 0.442351] ra : serial8250_do_startup+0x2c8/0x88e
...
[ 0.442416] console_on_rootfs+0x26/0x70
Fixes: c49436b657 ("serial: 8250_dw: Improve unwritable LCR workaround")
Link: https://lore.kernel.org/all/84cydt5peu.fsf@jogness.linutronix.de/T/
Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/20250723023322.464-2-cuiyunhui@bytedance.com
[ Applied fix to serial8250_do_startup() instead of serial8250_initialize() ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6c0e9f05c9 upstream.
The dma_sync_sg_for_device() functions should be called with the same
nents as the dma_map_sg(), not the value the map function returned
according to the documentation in Documentation/core-api/dma-api.rst:450:
With the sync_sg API, all the parameters must be the same
as those passed into the sg mapping API.
Fixes: da3564ee02 ("pch_uart: add multi-scatter processing")
Cc: stable <stable@kernel.org>
Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250701113452.18590-2-fourier.thomas@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit ff78538e07 ]
Programs using poll() on /dev/vcsa to be notified when VT changes occur
were missing one case: the switch from gfx to text mode.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Link: https://lore.kernel.org/r/9o5ro928-0pp4-05rq-70p4-ro385n21n723@onlyvoer.pbz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 41925b105e upstream.
xen_remap() is used to establish mappings for frames not under direct
control of the kernel: for Xenstore and console ring pages, and for
grant pages of non-PV guests.
Today xen_remap() is defined to use ioremap() on x86 (doing uncached
mappings), and ioremap_cache() on Arm (doing cached mappings).
Uncached mappings for those use cases are bad for performance, so they
should be avoided if possible. As all use cases of xen_remap() don't
require uncached mappings (the mapped area is always physical RAM),
a mapping using the standard WB cache mode is fine.
As sparse is flagging some of the xen_remap() use cases to be not
appropriate for iomem(), as the result is not annotated with the
__iomem modifier, eliminate xen_remap() completely and replace all
use cases with memremap() specifying the MEMREMAP_WB caching mode.
xen_unmap() can be replaced with memunmap().
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20220530082634.6339-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Teddy Astie <teddy.astie@vates.tech> [backport to 5.15.y]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 8d5cc8eed7 ]
The non-zero (true) return value from consw::con_switch() means a redraw
is needed. So make this return type a bool explicitly instead of int.
The latter might imply that -Eerrors are expected. They are not.
And document the hook.
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-parisc@vger.kernel.org
Tested-by: Helge Deller <deller@gmx.de> # parisc STI console
Link: https://lore.kernel.org/r/20240122110401.7289-31-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 03bcbbb399 ("dummycon: Trigger redraw when switching consoles with deferred takeover")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 559f01a0ee ]
In consw::con_clear():
* Height is always 1, so drop it.
* Offsets and width are always unsigned values, so re-type them as such.
This needs a new __fbcon_clear() in the fbcon code to still handle
height which might not be 1 when called internally.
Note that tests for negative count/width are left in place -- they are
taken care of in the next patches.
And document the hook.
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-parisc@vger.kernel.org
Tested-by: Helge Deller <deller@gmx.de> # parisc STI console
Link: https://lore.kernel.org/r/20240122110401.7289-22-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 03bcbbb399 ("dummycon: Trigger redraw when switching consoles with deferred takeover")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit dae3e6b618 ]
The 'init' parameter of consw::con_init() is true for the first call of
the hook on a particular console. So make the parameter a bool.
And document the hook.
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-parisc@vger.kernel.org
Tested-by: Helge Deller <deller@gmx.de> # parisc STI console
Link: https://lore.kernel.org/r/20240122110401.7289-21-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 03bcbbb399 ("dummycon: Trigger redraw when switching consoles with deferred takeover")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 4173f018aa ]
struct uni_pagedir contains 32 unicode page directories, so the name of
the structure is a bit misleading. Rename the structure to uni_pagedict,
so it looks like this:
struct uni_pagedict
-> 32 page dirs
-> 32 rows
-> 64 glyphs
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220607104946.18710-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 03bcbbb399 ("dummycon: Trigger redraw when switching consoles with deferred takeover")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6bd697b5fc ]
When two instances of uart devices are probing, a concurrency race can
occur. If one thread calls uart_register_driver function, which first
allocates and assigns memory to 'uart_state' member of uart_driver
structure, the other instance can bypass uart driver registration and
call ulite_assign. This calls uart_add_one_port, which expects the uart
driver to be fully initialized. This leads to a kernel panic due to a
null pointer dereference:
[ 8.143581] BUG: kernel NULL pointer dereference, address: 00000000000002b8
[ 8.156982] #PF: supervisor write access in kernel mode
[ 8.156984] #PF: error_code(0x0002) - not-present page
[ 8.156986] PGD 0 P4D 0
...
[ 8.180668] RIP: 0010:mutex_lock+0x19/0x30
[ 8.188624] Call Trace:
[ 8.188629] ? __die_body.cold+0x1a/0x1f
[ 8.195260] ? page_fault_oops+0x15c/0x290
[ 8.209183] ? __irq_resolve_mapping+0x47/0x80
[ 8.209187] ? exc_page_fault+0x64/0x140
[ 8.209190] ? asm_exc_page_fault+0x22/0x30
[ 8.209196] ? mutex_lock+0x19/0x30
[ 8.223116] uart_add_one_port+0x60/0x440
[ 8.223122] ? proc_tty_register_driver+0x43/0x50
[ 8.223126] ? tty_register_driver+0x1ca/0x1e0
[ 8.246250] ulite_probe+0x357/0x4b0 [uartlite]
To prevent it, move uart driver registration in to init function. This
will ensure that uart_driver is always registered when probe function
is called.
Signed-off-by: Jakub Lewalski <jakub.lewalski@nokia.com>
Signed-off-by: Elodie Decerle <elodie.decerle@nokia.com>
Link: https://lore.kernel.org/r/20250331160732.2042-1-elodie.decerle@nokia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 651dee0369 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5f10170699 upstream.
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>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 239f11209e upstream.
Relocate the runtime PM enable operation to sci_probe_single(). This change
prepares the codebase for upcoming fixes.
While at it, replace the existing logic with a direct call to
devm_pm_runtime_enable() and remove sci_cleanup_single(). The
devm_pm_runtime_enable() function automatically handles disabling runtime
PM during driver removal.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://lore.kernel.org/r/20250116182249.3828577-3-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 7cc0e0a43a upstream.
On the Renesas RZ/G3S, when doing suspend to RAM, the uart_suspend_port()
is called. The uart_suspend_port() calls 3 times the
struct uart_port::ops::tx_empty() before shutting down the port.
According to the documentation, the struct uart_port::ops::tx_empty()
API tests whether the transmitter FIFO and shifter for the port is
empty.
The Renesas RZ/G3S SCIFA IP reports the number of data units stored in the
transmit FIFO through the FDR (FIFO Data Count Register). The data units
in the FIFOs are written in the shift register and transmitted from there.
The TEND bit in the Serial Status Register reports if the data was
transmitted from the shift register.
In the previous code, in the tx_empty() API implemented by the sh-sci
driver, it is considered that the TX is empty if the hardware reports the
TEND bit set and the number of data units in the FIFO is zero.
According to the HW manual, the TEND bit has the following meaning:
0: Transmission is in the waiting state or in progress.
1: Transmission is completed.
It has been noticed that when opening the serial device w/o using it and
then switch to a power saving mode, the tx_empty() call in the
uart_port_suspend() function fails, leading to the "Unable to drain
transmitter" message being printed on the console. This is because the
TEND=0 if nothing has been transmitted and the FIFOs are empty. As the
TEND=0 has double meaning (waiting state, in progress) we can't
determined the scenario described above.
Add a software workaround for this. This sets a variable if any data has
been sent on the serial console (when using PIO) or if the DMA callback has
been called (meaning something has been transmitted). In the tx_empty()
API the status of the DMA transaction is also checked and if it is
completed or in progress the code falls back in checking the hardware
registers instead of relying on the software variable.
Fixes: 73a19e4c03 ("serial: sh-sci: Add DMA support.")
Cc: stable@vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://lore.kernel.org/r/20241125115856.513642-1-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[claudiu.beznea: fixed conflict by:
- keeping serial_port_out() instead of sci_port_out() in
sci_transmit_chars()
- keeping !uart_circ_empty(xmit) condition in sci_dma_tx_complete(),
after s->tx_occurred = true; assignement]
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c4c7ead7b8 ]
They are listed amon those cmd values that "treat 'arg' as an integer"
which is wrong. They should instead fall into the default case. Probably
nobody ever relied on that code since 2009 but still.
Fixes: e92166517e ("tty: handle VT specific compat ioctls in vt driver")
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/pr214s15-36r8-6732-2pop-159nq85o48r7@syhkavp.arg
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 86bcae88c9 ]
devm_ioremap() can return NULL on error. Currently, mlb_usio_probe()
does not check for this case, which could result in a NULL pointer
dereference.
Add NULL check after devm_ioremap() to prevent this issue.
Fixes: ba44dc0430 ("serial: Add Milbeaut serial control")
Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
Link: https://lore.kernel.org/r/20250403070339.64990-1-bsdhenrymartin@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit e1ca3ff28a upstream.
startup()/shutdown() callbacks access SIFIVE_SERIAL_IE_OFFS.
The register is also accessed from write() callback.
If console were printing and startup()/shutdown() callback
gets called, its access to the register could be overwritten.
Add port->lock to startup()/shutdown() callbacks to make sure
their access to SIFIVE_SERIAL_IE_OFFS is synchronized against
write() callback.
Fixes: 45c054d081 ("tty: serial: add driver for the SiFive UART")
Signed-off-by: Ryo Takakura <ryotkkr98@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Rule: add
Link: https://lore.kernel.org/stable/20250330003522.386632-1-ryotkkr98%40gmail.com
Link: https://lore.kernel.org/r/20250412001847.183221-1-ryotkkr98@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit f5cb528d64 ]
According to the LPUART reference manual, TXRTSE and TXRTSPOL of MODIR
register only can be changed when the transmitter is disabled.
So disable the transmitter before changing RS485 related registers and
re-enable it after the change is done.
Fixes: 67b0183786 ("tty: serial: lpuart: Add RS485 support for 32-bit uart flavour")
Cc: stable <stable@kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250312022503.1342990-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d57d56e4dd ]
For lpuart32 platforms, UARTMODIR register is used instead of UARTMODEM.
So here should configure the corresponding UARTMODIR register bits to
avoid confusion.
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230414022111.20896-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: f5cb528d64 ("tty: serial: fsl_lpuart: disable transmitter before changing RS485 related registers")
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit a26503092c upstream.
When flushing transmit side DMA, it is the transmit channel that should
be terminated, not the receive channel.
Fixes: 9e512eaaf8 ("serial: 8250: Fix fifo underflow on flush")
Cc: stable <stable@kernel.org>
Reported-by: Wentao Guan <guanwentao@uniontech.com>
Signed-off-by: John Keeping <jkeeping@inmusicbrands.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20250224121831.1429323-1-jkeeping@inmusicbrands.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 0b32216557 upstream.
Each of the 4 PCI functions on ASIX AX99100 PCIe to Multi I/O
Controller can be configured as a single-port serial port controller.
The subvendor id is 0x1000 when configured as serial port and MSI
interrupts are supported.
Signed-off-by: Jiaqing Zhao <jiaqing.zhao@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230724083933.3173513-4-jiaqing.zhao@linux.intel.com
Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9e512eaaf8 upstream.
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>
commit b06f388994 upstream.
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: Sean Anderson <sean.anderson@linux.dev>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9f7dea875c upstream.
In the sh-sci driver, sci_ports[0] is used by earlycon. If the earlycon is
still active when sci_probe() is called and the new serial port is supposed
to map to sci_ports[0], return -EBUSY to prevent breaking the earlycon.
This situation should occurs in debug scenarios, and users should be
aware of the potential conflict.
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/20250116182249.3828577-4-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit eaeee4225d upstream.
The port_cfg object is used by serial_console_write(), which serves as
the write function for the earlycon device. Marking port_cfg as __initdata
causes it to be freed after kernel initialization, resulting in earlycon
becoming unavailable thereafter. Remove the __initdata macro from port_cfg
to resolve this issue.
Fixes: 0b0cced19a ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable@vger.kernel.org
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Fixes: 0b0cced19a ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Link: https://lore.kernel.org/r/20250116182249.3828577-2-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b5a23a60e8 upstream.
When CONFIG_DMA_ENGINE is disabled, the driver now fails to build:
drivers/tty/serial/amba-pl011.c: In function 'pl011_unthrottle_rx':
drivers/tty/serial/amba-pl011.c:1822:16: error: 'struct uart_amba_port' has no member named 'using_rx_dma'
1822 | if (uap->using_rx_dma) {
| ^~
drivers/tty/serial/amba-pl011.c:1823:20: error: 'struct uart_amba_port' has no member named 'dmacr'
1823 | uap->dmacr |= UART011_RXDMAE;
| ^~
drivers/tty/serial/amba-pl011.c:1824:32: error: 'struct uart_amba_port' has no member named 'dmacr'
1824 | pl011_write(uap->dmacr, uap, REG_DMACR);
| ^~
Add the missing #ifdef check around these field accesses, matching
what other parts of this driver do.
Fixes: 2bcacc1c87 ("serial: amba-pl011: Fix RX stall when DMA is used")
Cc: stable <stable@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202411140617.nkjeHhsK-lkp@intel.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20241115110021.744332-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 2bcacc1c87 ]
Function pl011_throttle_rx() calls pl011_stop_rx() to disable RX, which
also disables the RX DMA by clearing the RXDMAE bit of the DMACR
register. However, to properly unthrottle RX when DMA is used, the
function pl011_unthrottle_rx() is expected to set the RXDMAE bit of
the DMACR register, which it currently lacks. This causes RX to stall
after the throttle API is called.
Set RXDMAE bit in the DMACR register while unthrottling RX if RX DMA is
used.
Fixes: 211565b100 ("serial: pl011: UPSTAT_AUTORTS requires .throttle/unthrottle")
Cc: stable@vger.kernel.org
Signed-off-by: Kartik Rajput <kkartik@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20241113092629.60226-1-kkartik@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 68ca3e72d7 ]
When a serial port is used for kernel console output, then all
modifications to the UART registers which are done from other contexts,
e.g. getty, termios, are interference points for the kernel console.
So far this has been ignored and the printk output is based on the
principle of hope. The rework of the console infrastructure which aims to
support threaded and atomic consoles, requires to mark sections which
modify the UART registers as unsafe. This allows the atomic write function
to make informed decisions and eventually to restore operational state. It
also allows to prevent the regular UART code from modifying UART registers
while printk output is in progress.
All modifications of UART registers are guarded by the UART port lock,
which provides an obvious synchronization point with the console
infrastructure.
To avoid adding this functionality to all UART drivers, wrap the
spin_[un]lock*() invocations for uart_port::lock into helper functions
which just contain the spin_[un]lock*() invocations for now. In a
subsequent step these helpers will gain the console synchronization
mechanisms.
Converted with coccinelle. No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/r/20230914183831.587273-18-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 2bcacc1c87 ("serial: amba-pl011: Fix RX stall when DMA is used")
Signed-off-by: Sasha Levin <sashal@kernel.org>
