kernel/linux.git/drivers/tty, branch v5.4.50

Revert "tty: hvc: Fix data abort due to race in hvc_open"

2020-06-30T19:37:13+00:00

commit cf9c94456ebafc6d75a834e58dfdc8ae71a3acbc upstream. This reverts commit e2bd1dcbe1aa34ff5570b3427c530e4332ecf0fe. In discussion on the mailing list, it has been determined that this is not the correct type of fix for this issue. Revert it so that we can do this correctly. Reported-by: Jiri Slaby Reported-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20200428032601.22127-1-rananta@codeaurora.org Cc: Raghavendra Rao Ananta Signed-off-by: Greg Kroah-Hartman

tty: n_gsm: Fix bogus i++ in gsm_data_kick

2020-06-24T15:50:29+00:00

[ Upstream commit 4dd31f1ffec6c370c3c2e0c605628bf5e16d5c46 ] When submitting the previous fix "tty: n_gsm: Fix waking up upper tty layer when room available". It was suggested to switch from a while to a for loop, but when doing it, there was a remaining bogus i++. This patch removes this i++ and also reorganizes the code making it more compact. Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Signed-off-by: Gregory CLEMENT Link: https://lore.kernel.org/r/20200518084517.2173242-3-gregory.clement@bootlin.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

tty: n_gsm: Fix waking up upper tty layer when room available

2020-06-24T15:50:27+00:00

[ Upstream commit 01dbb362f0a114fbce19c8abe4cd6f4710e934d5 ] Warn the upper layer when n_gms is ready to receive data again. Without this the associated virtual tty remains blocked indefinitely. Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Signed-off-by: Gregory CLEMENT Link: https://lore.kernel.org/r/20200512115323.1447922-4-gregory.clement@bootlin.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

tty: n_gsm: Fix SOF skipping

2020-06-24T15:50:27+00:00

[ Upstream commit 84d6f81c1fb58b56eba81ff0a36cf31946064b40 ] For at least some modems like the TELIT LE910, skipping SOF makes transfers blocking indefinitely after a short amount of data transferred. Given the small improvement provided by skipping the SOF (just one byte on about 100 bytes), it seems better to completely remove this "feature" than make it optional. Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Signed-off-by: Gregory CLEMENT Link: https://lore.kernel.org/r/20200512115323.1447922-3-gregory.clement@bootlin.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: amba-pl011: Make sure we initialize the port.lock spinlock

2020-06-24T15:50:24+00:00

[ Upstream commit 8508f4cba308f785b2fd4b8c38849c117b407297 ] Valentine reported seeing: [ 3.626638] INFO: trying to register non-static key. [ 3.626639] the code is fine but needs lockdep annotation. [ 3.626640] turning off the locking correctness validator. [ 3.626644] CPU: 7 PID: 51 Comm: kworker/7:1 Not tainted 5.7.0-rc2-00115-g8c2e9790f196 #116 [ 3.626646] Hardware name: HiKey960 (DT) [ 3.626656] Workqueue: events deferred_probe_work_func [ 3.632476] sd 0:0:0:0: [sda] Optimal transfer size 8192 bytes not a multiple of physical block size (16384 bytes) [ 3.640220] Call trace: [ 3.640225] dump_backtrace+0x0/0x1b8 [ 3.640227] show_stack+0x20/0x30 [ 3.640230] dump_stack+0xec/0x158 [ 3.640234] register_lock_class+0x598/0x5c0 [ 3.640235] __lock_acquire+0x80/0x16c0 [ 3.640236] lock_acquire+0xf4/0x4a0 [ 3.640241] _raw_spin_lock_irqsave+0x70/0xa8 [ 3.640245] uart_add_one_port+0x388/0x4b8 [ 3.640248] pl011_register_port+0x70/0xf0 [ 3.640250] pl011_probe+0x184/0x1b8 [ 3.640254] amba_probe+0xdc/0x180 [ 3.640256] really_probe+0xe0/0x338 [ 3.640257] driver_probe_device+0x60/0xf8 [ 3.640259] __device_attach_driver+0x8c/0xd0 [ 3.640260] bus_for_each_drv+0x84/0xd8 [ 3.640261] __device_attach+0xe4/0x140 [ 3.640263] device_initial_probe+0x1c/0x28 [ 3.640265] bus_probe_device+0xa4/0xb0 [ 3.640266] deferred_probe_work_func+0x7c/0xb8 [ 3.640269] process_one_work+0x2c0/0x768 [ 3.640271] worker_thread+0x4c/0x498 [ 3.640272] kthread+0x14c/0x158 [ 3.640275] ret_from_fork+0x10/0x1c Which seems to be due to the fact that after allocating the uap structure, nothing initializes the spinlock. Its a little confusing, as uart_port_spin_lock_init() is one place where the lock is supposed to be initialized, but it has an exception for the case where the port is a console. This makes it seem like a deeper fix is needed to properly register the console, but I'm not sure what that entails, and Andy suggested that this approach is less invasive. Thus, this patch resolves the issue by initializing the spinlock in the driver, and resolves the resulting warning. Cc: Andy Shevchenko Cc: Russell King Cc: Jiri Slaby Cc: linux-serial@vger.kernel.org Reported-by: Valentin Schneider Reviewed-by: Andy Shevchenko Signed-off-by: John Stultz Reviewed-and-tested-by: Valentin Schneider Link: https://lore.kernel.org/r/20200428184050.6501-1-john.stultz@linaro.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

tty: hvc: Fix data abort due to race in hvc_open

2020-06-24T15:50:22+00:00

[ Upstream commit e2bd1dcbe1aa34ff5570b3427c530e4332ecf0fe ] Potentially, hvc_open() can be called in parallel when two tasks calls open() on /dev/hvcX. In such a scenario, if the hp->ops->notifier_add() callback in the function fails, where it sets the tty->driver_data to NULL, the parallel hvc_open() can see this NULL and cause a memory abort. Hence, serialize hvc_open and check if tty->private_data is NULL before proceeding ahead. The issue can be easily reproduced by launching two tasks simultaneously that does nothing but open() and close() on /dev/hvcX. For example: $ ./simple_open_close /dev/hvc0 & ./simple_open_close /dev/hvc0 & Signed-off-by: Raghavendra Rao Ananta Link: https://lore.kernel.org/r/20200428032601.22127-1-rananta@codeaurora.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: 8250: Fix max baud limit in generic 8250 port

2020-06-24T15:50:13+00:00

[ Upstream commit 7b668c064ec33f3d687c3a413d05e355172e6c92 ] Standard 8250 UART ports are designed in a way so they can communicate with baud rates up to 1/16 of a reference frequency. It's expected from most of the currently supported UART controllers. That's why the former version of serial8250_get_baud_rate() method called uart_get_baud_rate() with min and max baud rates passed as (port->uartclk / 16 / UART_DIV_MAX) and ((port->uartclk + tolerance) / 16) respectively. Doing otherwise, like it was suggested in commit ("serial: 8250_mtk: support big baud rate."), caused acceptance of bauds, which was higher than the normal UART controllers actually supported. As a result if some user-space program requested to set a baud greater than (uartclk / 16) it would have been permitted without truncation, but then serial8250_get_divisor(baud) (which calls uart_get_divisor() to get the reference clock divisor) would have returned a zero divisor. Setting zero divisor will cause an unpredictable effect varying from chip to chip. In case of DW APB UART the communications just stop. Lets fix this problem by getting back the limitation of (uartclk + tolerance) / 16 maximum baud supported by the generic 8250 port. Mediatek 8250 UART ports driver developer shouldn't have touched it in the first place notably seeing he already provided a custom version of set_termios() callback in that glue-driver which took into account the extended baud rate values and accordingly updated the standard and vendor-specific divisor latch registers anyway. Fixes: 81bb549fdf14 ("serial: 8250_mtk: support big baud rate.") Signed-off-by: Serge Semin Cc: Alexey Malahov Cc: Thomas Bogendoerfer Cc: Paul Burton Cc: Ralf Baechle Cc: Arnd Bergmann Cc: Long Cheng Cc: Andy Shevchenko Cc: Maxime Ripard Cc: Catalin Marinas Cc: Will Deacon Cc: Russell King Cc: linux-mips@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-mediatek@lists.infradead.org Link: https://lore.kernel.org/r/20200506233136.11842-2-Sergey.Semin@baikalelectronics.ru Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: 8250: Avoid error message on reprobe

2020-06-22T07:31:18+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 Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: Move Pericom IDs to pci_ids.h

2020-06-22T07:31:17+00:00

[ Upstream commit 62a7f3009a460001eb46984395280dd900bc4ef4 ] Move the IDs to pci_ids.h so it can be used by next patch. Link: https://lore.kernel.org/r/20200508065343.32751-1-kai.heng.feng@canonical.com Signed-off-by: Kai-Heng Feng Signed-off-by: Bjorn Helgaas Acked-by: Greg Kroah-Hartman Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin

kgdboc: Use a platform device to handle tty drivers showing up late

2020-06-22T07:31:06+00:00

[ Upstream commit 68e55f61c13842baf825958129698c5371db432c ] If you build CONFIG_KGDB_SERIAL_CONSOLE into the kernel then you should be able to have KGDB init itself at bootup by specifying the "kgdboc=..." kernel command line parameter. This has worked OK for me for many years, but on a new device I switched to it stopped working. The problem is that on this new device the serial driver gets its probe deferred. Now when kgdb initializes it can't find the tty driver and when it gives up it never tries again. We could try to find ways to move up the initialization of the serial driver and such a thing might be worthwhile, but it's nice to be robust against serial drivers that load late. We could move kgdb to init itself later but that penalizes our ability to debug early boot code on systems where the driver inits early. We could roll our own system of detecting when new tty drivers get loaded and then use that to figure out when kgdb can init, but that's ugly. Instead, let's jump on the -EPROBE_DEFER bandwagon. We'll create a singleton instance of a "kgdboc" platform device. If we can't find our tty device when the singleton "kgdboc" probes we'll return -EPROBE_DEFER which means that the system will call us back later to try again when the tty device might be there. We won't fully transition all of the kgdboc to a platform device because early kgdb initialization (via the "ekgdboc" kernel command line parameter) still runs before the platform device has been created. The kgdb platform device is merely used as a convenient way to hook into the system's normal probe deferral mechanisms. As part of this, we'll ever-so-slightly change how the "kgdboc=..." kernel command line parameter works. Previously if you booted up and kgdb couldn't find the tty driver then later reading '/sys/module/kgdboc/parameters/kgdboc' would return a blank string. Now kgdb will keep track of the string that came as part of the command line and give it back to you. It's expected that this should be an OK change. Signed-off-by: Douglas Anderson Reviewed-by: Greg Kroah-Hartman Reviewed-by: Daniel Thompson Link: https://lore.kernel.org/r/20200507130644.v4.3.I4a493cfb0f9f740ce8fd2ab58e62dc92d18fed30@changeid [daniel.thompson@linaro.org: Make config_mutex static] Signed-off-by: Daniel Thompson Signed-off-by: Sasha Levin