linux-stable.git/drivers/tty/serial, branch v4.4.263

serial: 8250_omap: Avoid FIFO corruption caused by MDR1 access

2020-12-29T12:42:33+00:00

commit d96f04d347e4011977abdbb4da5d8f303ebd26f8 upstream.

It has been observed that once per 300-1300 port openings the first
transmitted byte is being corrupted on AM3352 ("v" written to FIFO appeared
as "e" on the wire). It only happened if single byte has been transmitted
right after port open, which means, DMA is not used for this transfer and
the corruption never happened afterwards.

Therefore I've carefully re-read the MDR1 errata (link below), which says
"when accessing the MDR1 registers that causes a dummy under-run condition
that will freeze the UART in IrDA transmission. In UART mode, this may
corrupt the transferred data". Strictly speaking,
omap_8250_mdr1_errataset() performs a read access and if the value is the
same as should be written, exits without errata-recommended FIFO reset.

A brief check of the serial_omap_mdr1_errataset() from the competing
omap-serial driver showed it has no read access of MDR1. After removing the
read access from omap_8250_mdr1_errataset() the data corruption never
happened any more.

Link: https://www.ti.com/lit/er/sprz360i/sprz360i.pdf
Fixes: 61929cf0169d ("tty: serial: Add 8250-core based omap driver")
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Sverdlin 
Link: https://lore.kernel.org/r/20201210055257.1053028-1-alexander.sverdlin@gmail.com
Signed-off-by: Greg Kroah-Hartman

tty: serial: imx: keep console clocks always on

2020-11-24T11:48:12+00:00

commit e67c139c488e84e7eae6c333231e791f0e89b3fb upstream.

For below code, there has chance to cause deadlock in SMP system:
Thread 1:
clk_enable_lock();
pr_info("debug message");
clk_enable_unlock();

Thread 2:
imx_uart_console_write()
	clk_enable()
		clk_enable_lock();

Thread 1:
Acuired clk enable_lock -> printk -> console_trylock_spinning
Thread 2:
console_unlock() -> imx_uart_console_write -> clk_disable -> Acquite clk enable_lock

So the patch is to keep console port clocks always on like
other console drivers.

Fixes: 1cf93e0d5488 ("serial: imx: remove the uart_console() check")
Acked-by: Uwe Kleine-König 
Signed-off-by: Fugang Duan 
Link: https://lore.kernel.org/r/20201111025136.29818-1-fugang.duan@nxp.com
Cc: stable 
[fix up build warning - gregkh]
Signed-off-by: Greg Kroah-Hartman

serial: txx9: add missing platform_driver_unregister() on error in serial_txx9_init

2020-11-10T09:22:20+00:00

commit 0c5fc92622ed5531ff324b20f014e9e3092f0187 upstream.

Add the missing platform_driver_unregister() before return
from serial_txx9_init in the error handling case when failed
to register serial_txx9_pci_driver with macro ENABLE_SERIAL_TXX9_PCI
defined.

Fixes: ab4382d27412 ("tty: move drivers/serial/ to drivers/tty/serial/")
Signed-off-by: Qinglang Miao 
Link: https://lore.kernel.org/r/20201103084942.109076-1-miaoqinglang@huawei.com
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_mtk: Fix uart_get_baud_rate warning

2020-11-10T09:22:20+00:00

commit 912ab37c798770f21b182d656937072b58553378 upstream.

Mediatek 8250 port supports speed higher than uartclk / 16. If the baud
rates in both the new and the old termios setting are higher than
uartclk / 16, the WARN_ON in uart_get_baud_rate() will be triggered.
Passing NULL as the old termios so uart_get_baud_rate() will use
uartclk / 16 - 1 as the new baud rate which will be replaced by the
original baud rate later by tty_termios_encode_baud_rate() in
mtk8250_set_termios().

Fixes: 551e553f0d4a ("serial: 8250_mtk: Fix high-speed baud rates clamping")
Signed-off-by: Claire Chang 
Link: https://lore.kernel.org/r/20201102120749.374458-1-tientzu@chromium.org
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

tty: serial: earlycon dependency

2020-10-29T08:03:03+00:00

[ Upstream commit 0fb9342d06b0f667b915ba58bfefc030e534a218 ]

parse_options() in drivers/tty/serial/earlycon.c calls uart_parse_earlycon
in drivers/tty/serial/serial_core.c therefore selecting SERIAL_EARLYCON
should automatically select SERIAL_CORE, otherwise will result in symbol
not found error during linking if SERIAL_CORE is not configured as builtin

Fixes: 9aac5887595b ("tty/serial: add generic serial earlycon")
Signed-off-by: Tong Zhang 
Link: https://lore.kernel.org/r/20200828123949.2642-1-ztong0001@gmail.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: serial: samsung: Correct clock selection logic

2020-10-01T09:11:55+00:00

[ Upstream commit 7d31676a8d91dd18e08853efd1cb26961a38c6a6 ]

Some variants of the samsung tty driver can pick which clock
to use for their baud rate generation.  In the DT conversion,
a default clock was selected to be used if a specific one wasn't
assigned and then a comparison of which clock rate worked better
was done.  Unfortunately, the comparison was implemented in such
a way that only the default clock was ever actually compared.
Fix this by iterating through all possible clocks, except when a
specific clock has already been picked via clk_sel (which is
only possible via board files).

Signed-off-by: Jonathan Bakker 
Reviewed-by: Krzysztof Kozlowski 
Link: https://lore.kernel.org/r/BN6PR04MB06604E63833EA41837EBF77BA3A30@BN6PR04MB0660.namprd04.prod.outlook.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250_omap: Fix sleeping function called from invalid context during probe

2020-10-01T09:11:54+00:00

[ Upstream commit 4ce35a3617c0ac758c61122b2218b6c8c9ac9398 ]

When booting j721e the following bug is printed:

[    1.154821] BUG: sleeping function called from invalid context at kernel/sched/completion.c:99
[    1.154827] in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 12, name: kworker/0:1
[    1.154832] 3 locks held by kworker/0:1/12:
[    1.154836]  #0: ffff000840030728 ((wq_completion)events){+.+.}, at: process_one_work+0x1d4/0x6e8
[    1.154852]  #1: ffff80001214fdd8 (deferred_probe_work){+.+.}, at: process_one_work+0x1d4/0x6e8
[    1.154860]  #2: ffff00084060b170 (&dev->mutex){....}, at: __device_attach+0x38/0x138
[    1.154872] irq event stamp: 63096
[    1.154881] hardirqs last  enabled at (63095): [] _raw_spin_unlock_irqrestore+0x70/0x78
[    1.154887] hardirqs last disabled at (63096): [] _raw_spin_lock_irqsave+0x28/0x80
[    1.154893] softirqs last  enabled at (62254): [] _stext+0x488/0x564
[    1.154899] softirqs last disabled at (62247): [] irq_exit+0x114/0x140
[    1.154906] CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.6.0-rc6-next-20200318-00094-g45e4089b0bd3 #221
[    1.154911] Hardware name: Texas Instruments K3 J721E SoC (DT)
[    1.154917] Workqueue: events deferred_probe_work_func
[    1.154923] Call trace:
[    1.154928]  dump_backtrace+0x0/0x190
[    1.154933]  show_stack+0x14/0x20
[    1.154940]  dump_stack+0xe0/0x148
[    1.154946]  ___might_sleep+0x150/0x1f0
[    1.154952]  __might_sleep+0x4c/0x80
[    1.154957]  wait_for_completion_timeout+0x40/0x140
[    1.154964]  ti_sci_set_device_state+0xa0/0x158
[    1.154969]  ti_sci_cmd_get_device_exclusive+0x14/0x20
[    1.154977]  ti_sci_dev_start+0x34/0x50
[    1.154984]  genpd_runtime_resume+0x78/0x1f8
[    1.154991]  __rpm_callback+0x3c/0x140
[    1.154996]  rpm_callback+0x20/0x80
[    1.155001]  rpm_resume+0x568/0x758
[    1.155007]  __pm_runtime_resume+0x44/0xb0
[    1.155013]  omap8250_probe+0x2b4/0x508
[    1.155019]  platform_drv_probe+0x50/0xa0
[    1.155023]  really_probe+0xd4/0x318
[    1.155028]  driver_probe_device+0x54/0xe8
[    1.155033]  __device_attach_driver+0x80/0xb8
[    1.155039]  bus_for_each_drv+0x74/0xc0
[    1.155044]  __device_attach+0xdc/0x138
[    1.155049]  device_initial_probe+0x10/0x18
[    1.155053]  bus_probe_device+0x98/0xa0
[    1.155058]  deferred_probe_work_func+0x74/0xb0
[    1.155063]  process_one_work+0x280/0x6e8
[    1.155068]  worker_thread+0x48/0x430
[    1.155073]  kthread+0x108/0x138
[    1.155079]  ret_from_fork+0x10/0x18

To fix the bug we need to first call pm_runtime_enable() prior to any
pm_runtime calls.

Reported-by: Tomi Valkeinen 
Signed-off-by: Peter Ujfalusi 
Link: https://lore.kernel.org/r/20200320125200.6772-1-peter.ujfalusi@ti.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250: Avoid error message on reprobe

2020-10-01T09:11:50+00:00

commit e0a851fe6b9b619527bd928aa93caaddd003f70c upstream.

If the call to uart_add_one_port() in serial8250_register_8250_port()
fails, a half-initialized entry in the serial_8250ports[] array is left
behind.

A subsequent reprobe of the same serial port causes that entry to be
reused.  Because uart->port.dev is set, uart_remove_one_port() is called
for the half-initialized entry and bails out with an error message:

bcm2835-aux-uart 3f215040.serial: Removing wrong port: (null) != (ptrval)

The same happens on failure of mctrl_gpio_init() since commit
4a96895f74c9 ("tty/serial/8250: use mctrl_gpio helpers").

Fix by zeroing the uart->port.dev pointer in the probe error path.

The bug was introduced in v2.6.10 by historical commit befff6f5bf5f
("[SERIAL] Add new port registration/unregistration functions."):
https://git.kernel.org/tglx/history/c/befff6f5bf5f

The commit added an unconditional call to uart_remove_one_port() in
serial8250_register_port().  In v3.7, commit 835d844d1a28 ("8250_pnp:
do pnp probe before legacy probe") made that call conditional on
uart->port.dev which allows me to fix the issue by zeroing that pointer
in the error path.  Thus, the present commit will fix the problem as far
back as v3.7 whereas still older versions need to also cherry-pick
835d844d1a28.

Fixes: 835d844d1a28 ("8250_pnp: do pnp probe before legacy probe")
Signed-off-by: Lukas Wunner 
Cc: stable@vger.kernel.org # v2.6.10
Cc: stable@vger.kernel.org # v2.6.10: 835d844d1a28: 8250_pnp: do pnp probe before legacy
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/b4a072013ee1a1d13ee06b4325afb19bda57ca1b.1589285873.git.lukas@wunner.de
[iwamatsu: Backported to 4.4, 4.9: adjust context]
Signed-off-by: Nobuhiro Iwamatsu (CIP) 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: Add Realtek 816a and 816b

2020-09-23T06:44:27+00:00

commit 3c5a87be170aba8ac40982182f812dcff6ed1ad1 upstream.

These serial ports are exposed by the OOB-management-engine on
RealManage-enabled network cards (e.g. AMD DASH enabled systems using
Realtek cards).

Because these have 3 BARs, they fail the "num_iomem <= 1" check in
serial_pci_guess_board.

I've manually checked the two IOMEM regions and BAR 2 doesn't seem to
respond to reads, but BAR 4 seems to be an MMIO version of the IO ports
(untested).

With this change, the ports are detected:
0000:02:00.1: ttyS0 at I/O 0x2200 (irq = 82, base_baud = 115200) is a 16550A
0000:02:00.2: ttyS1 at I/O 0x2100 (irq = 55, base_baud = 115200) is a 16550A

lspci output:
02:00.1 0700: 10ec:816a (rev 0e) (prog-if 02 [16550])
        Subsystem: 17aa:5082
        Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort+ SERR- 
Cc: stable 
Link: https://lore.kernel.org/r/20200914173628.GA22508@yamamaya.is-a-geek.org
Signed-off-by: Greg Kroah-Hartman

serial: 8250: change lock order in serial8250_do_startup()

2020-09-03T09:19:26+00:00

commit 205d300aea75623e1ae4aa43e0d265ab9cf195fd upstream.

We have a number of "uart.port->desc.lock vs desc.lock->uart.port"
lockdep reports coming from 8250 driver; this causes a bit of trouble
to people, so let's fix it.

The problem is reverse lock order in two different call paths:

chain #1:

 serial8250_do_startup()
  spin_lock_irqsave(&port->lock);
   disable_irq_nosync(port->irq);
    raw_spin_lock_irqsave(&desc->lock)

chain #2:

  __report_bad_irq()
   raw_spin_lock_irqsave(&desc->lock)
    for_each_action_of_desc()
     printk()
      spin_lock_irqsave(&port->lock);

Fix this by changing the order of locks in serial8250_do_startup():
 do disable_irq_nosync() first, which grabs desc->lock, and grab
 uart->port after that, so that chain #1 and chain #2 have same lock
 order.

Full lockdep splat:

 ======================================================
 WARNING: possible circular locking dependency detected
 5.4.39 #55 Not tainted
 ======================================================

 swapper/0/0 is trying to acquire lock:
 ffffffffab65b6c0 (console_owner){-...}, at: console_lock_spinning_enable+0x31/0x57

 but task is already holding lock:
 ffff88810a8e34c0 (&irq_desc_lock_class){-.-.}, at: __report_bad_irq+0x5b/0xba

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #2 (&irq_desc_lock_class){-.-.}:
        _raw_spin_lock_irqsave+0x61/0x8d
        __irq_get_desc_lock+0x65/0x89
        __disable_irq_nosync+0x3b/0x93
        serial8250_do_startup+0x451/0x75c
        uart_startup+0x1b4/0x2ff
        uart_port_activate+0x73/0xa0
        tty_port_open+0xae/0x10a
        uart_open+0x1b/0x26
        tty_open+0x24d/0x3a0
        chrdev_open+0xd5/0x1cc
        do_dentry_open+0x299/0x3c8
        path_openat+0x434/0x1100
        do_filp_open+0x9b/0x10a
        do_sys_open+0x15f/0x3d7
        kernel_init_freeable+0x157/0x1dd
        kernel_init+0xe/0x105
        ret_from_fork+0x27/0x50

 -> #1 (&port_lock_key){-.-.}:
        _raw_spin_lock_irqsave+0x61/0x8d
        serial8250_console_write+0xa7/0x2a0
        console_unlock+0x3b7/0x528
        vprintk_emit+0x111/0x17f
        printk+0x59/0x73
        register_console+0x336/0x3a4
        uart_add_one_port+0x51b/0x5be
        serial8250_register_8250_port+0x454/0x55e
        dw8250_probe+0x4dc/0x5b9
        platform_drv_probe+0x67/0x8b
        really_probe+0x14a/0x422
        driver_probe_device+0x66/0x130
        device_driver_attach+0x42/0x5b
        __driver_attach+0xca/0x139
        bus_for_each_dev+0x97/0xc9
        bus_add_driver+0x12b/0x228
        driver_register+0x64/0xed
        do_one_initcall+0x20c/0x4a6
        do_initcall_level+0xb5/0xc5
        do_basic_setup+0x4c/0x58
        kernel_init_freeable+0x13f/0x1dd
        kernel_init+0xe/0x105
        ret_from_fork+0x27/0x50

 -> #0 (console_owner){-...}:
        __lock_acquire+0x118d/0x2714
        lock_acquire+0x203/0x258
        console_lock_spinning_enable+0x51/0x57
        console_unlock+0x25d/0x528
        vprintk_emit+0x111/0x17f
        printk+0x59/0x73
        __report_bad_irq+0xa3/0xba
        note_interrupt+0x19a/0x1d6
        handle_irq_event_percpu+0x57/0x79
        handle_irq_event+0x36/0x55
        handle_fasteoi_irq+0xc2/0x18a
        do_IRQ+0xb3/0x157
        ret_from_intr+0x0/0x1d
        cpuidle_enter_state+0x12f/0x1fd
        cpuidle_enter+0x2e/0x3d
        do_idle+0x1ce/0x2ce
        cpu_startup_entry+0x1d/0x1f
        start_kernel+0x406/0x46a
        secondary_startup_64+0xa4/0xb0

 other info that might help us debug this:

 Chain exists of:
   console_owner --> &port_lock_key --> &irq_desc_lock_class

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&irq_desc_lock_class);
                                lock(&port_lock_key);
                                lock(&irq_desc_lock_class);
   lock(console_owner);

  *** DEADLOCK ***

 2 locks held by swapper/0/0:
  #0: ffff88810a8e34c0 (&irq_desc_lock_class){-.-.}, at: __report_bad_irq+0x5b/0xba
  #1: ffffffffab65b5c0 (console_lock){+.+.}, at: console_trylock_spinning+0x20/0x181

 stack backtrace:
 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.39 #55
 Hardware name: XXXXXX
 Call Trace:
  
  dump_stack+0xbf/0x133
  ? print_circular_bug+0xd6/0xe9
  check_noncircular+0x1b9/0x1c3
  __lock_acquire+0x118d/0x2714
  lock_acquire+0x203/0x258
  ? console_lock_spinning_enable+0x31/0x57
  console_lock_spinning_enable+0x51/0x57
  ? console_lock_spinning_enable+0x31/0x57
  console_unlock+0x25d/0x528
  ? console_trylock+0x18/0x4e
  vprintk_emit+0x111/0x17f
  ? lock_acquire+0x203/0x258
  printk+0x59/0x73
  __report_bad_irq+0xa3/0xba
  note_interrupt+0x19a/0x1d6
  handle_irq_event_percpu+0x57/0x79
  handle_irq_event+0x36/0x55
  handle_fasteoi_irq+0xc2/0x18a
  do_IRQ+0xb3/0x157
  common_interrupt+0xf/0xf
  

Signed-off-by: Sergey Senozhatsky 
Fixes: 768aec0b5bcc ("serial: 8250: fix shared interrupts issues with SMP and RT kernels")
Reported-by: Guenter Roeck 
Reported-by: Raul Rangel 
BugLink: https://bugs.chromium.org/p/chromium/issues/detail?id=1114800
Link: https://lore.kernel.org/lkml/CAHQZ30BnfX+gxjPm1DUd5psOTqbyDh4EJE=2=VAMW_VDafctkA@mail.gmail.com/T/#u
Reviewed-by: Andy Shevchenko 
Reviewed-by: Guenter Roeck 
Tested-by: Guenter Roeck 
Cc: stable 
Link: https://lore.kernel.org/r/20200817022646.1484638-1-sergey.senozhatsky@gmail.com
Signed-off-by: Greg Kroah-Hartman