kernel/linux.git/drivers/tty/serial, branch v4.14.85

sc16is7xx: Fix for multi-channel stall

2018-11-21T08:24:04+00:00

[ Upstream commit 8344498721059754e09d30fe255a12dab8fb03ef ] The SC16IS752 is a dual-channel device. The two channels are largely independent, but the IRQ signals are wired together as an open-drain, active low signal which will be driven low while either of the channels requires attention, which can be for significant periods of time until operations complete and the interrupt can be acknowledged. In that respect it is should be treated as a true level-sensitive IRQ. The kernel, however, needs to be able to exit interrupt context in order to use I2C or SPI to access the device registers (which may involve sleeping). Therefore the interrupt needs to be masked out or paused in some way. The usual way to manage sleeping from within an interrupt handler is to use a threaded interrupt handler - a regular interrupt routine does the minimum amount of work needed to triage the interrupt before waking the interrupt service thread. If the threaded IRQ is marked as IRQF_ONESHOT the kernel will automatically mask out the interrupt until the thread runs to completion. The sc16is7xx driver used to use a threaded IRQ, but a patch switched to using a kthread_worker in order to set realtime priorities on the handler thread and for other optimisations. The end result is non-threaded IRQ that schedules some work then returns IRQ_HANDLED, making the kernel think that all IRQ processing has completed. The work-around to prevent a constant stream of interrupts is to mark the interrupt as edge-sensitive rather than level-sensitive, but interpreting an active-low source as a falling-edge source requires care to prevent a total cessation of interrupts. Whereas an edge-triggering source will generate a new edge for every interrupt condition a level-triggering source will keep the signal at the interrupting level until it no longer requires attention; in other words, the host won't see another edge until all interrupt conditions are cleared. It is therefore vital that the interrupt handler does not exit with an outstanding interrupt condition, otherwise the kernel will not receive another interrupt unless some other operation causes the interrupt state on the device to be cleared. The existing sc16is7xx driver has a very simple interrupt "thread" (kthread_work job) that processes interrupts on each channel in turn until there are no more. If both channels are active and the first channel starts interrupting while the handler for the second channel is running then it will not be detected and an IRQ stall ensues. This could be handled easily if there was a shared IRQ status register, or a convenient way to determine if the IRQ had been deasserted for any length of time, but both appear to be lacking. Avoid this problem (or at least make it much less likely to happen) by reducing the granularity of per-channel interrupt processing to one condition per iteration, only exiting the overall loop when both channels are no longer interrupting. Signed-off-by: Phil Elwell Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

kgdboc: Passing ekgdboc to command line causes panic

2018-11-13T19:15:11+00:00

commit 1bd54d851f50dea6af30c3e6ff4f3e9aab5558f9 upstream. kgdboc_option_setup does not check input argument before passing it to strlen. The argument would be a NULL pointer if "ekgdboc", without its value, is set in command line and thus cause the following panic. PANIC: early exception 0xe3 IP 10:ffffffff8fbbb620 error 0 cr2 0x0 [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.18-rc8+ #1 [ 0.000000] RIP: 0010:strlen+0x0/0x20 ... [ 0.000000] Call Trace [ 0.000000] ? kgdboc_option_setup+0x9/0xa0 [ 0.000000] ? kgdboc_early_init+0x6/0x1b [ 0.000000] ? do_early_param+0x4d/0x82 [ 0.000000] ? parse_args+0x212/0x330 [ 0.000000] ? rdinit_setup+0x26/0x26 [ 0.000000] ? parse_early_options+0x20/0x23 [ 0.000000] ? rdinit_setup+0x26/0x26 [ 0.000000] ? parse_early_param+0x2d/0x39 [ 0.000000] ? setup_arch+0x2f7/0xbf4 [ 0.000000] ? start_kernel+0x5e/0x4c2 [ 0.000000] ? load_ucode_bsp+0x113/0x12f [ 0.000000] ? secondary_startup_64+0xa5/0xb0 This patch adds a check to prevent the panic. Cc: stable@vger.kernel.org Cc: jason.wessel@windriver.com Cc: gregkh@linuxfoundation.org Cc: jslaby@suse.com Signed-off-by: He Zhe Reviewed-by: Daniel Thompson Signed-off-by: Greg Kroah-Hartman

serial: mvebu-uart: Fix reporting of effective CSIZE to userspace

2018-10-10T06:54:18+00:00

commit e0bf2d4982fe7d9ddaf550dd023803ea286f47fc upstream. Apparently, this driver (or the hardware) does not support character length settings. It's apparently running in 8-bit mode, but it makes userspace believe it's in 5-bit mode. That makes tcsetattr with CS8 incorrectly fail, breaking e.g. getty from busybox, thus the login shell on ttyMVx. Fix by hard-wiring CS8 into c_cflag. Signed-off-by: Jan Kiszka Fixes: 30530791a7a0 ("serial: mvebu-uart: initial support for Armada-3700 serial port") Cc: stable # 4.6+ Signed-off-by: Greg Kroah-Hartman

serial: imx: restore handshaking irq for imx1

2018-10-04T00:00:57+00:00

commit 7e620984b62532783912312e334f3c48cdacbd5d upstream. Back in 2015 when irda was dropped from the driver imx1 was broken. This change reintroduces the support for the third interrupt of the UART. Fixes: afe9cbb1a6ad ("serial: imx: drop support for IRDA") Cc: stable Signed-off-by: Uwe Kleine-König Reviewed-by: Leonard Crestez Signed-off-by: Greg Kroah-Hartman

serial: cpm_uart: return immediately from console poll

2018-10-04T00:00:54+00:00

commit be28c1e3ca29887e207f0cbcd294cefe5074bab6 upstream. kgdb expects poll function to return immediately and returning NO_POLL_CHAR when no character is available. Fixes: f5316b4aea024 ("kgdb,8250,pl011: Return immediately from console poll") Cc: Jason Wessel Cc: Signed-off-by: Christophe Leroy Signed-off-by: Greg Kroah-Hartman

tty: serial: lpuart: avoid leaking struct tty_struct

2018-10-04T00:00:54+00:00

commit 3216c622a24b0ebb9c159a8d1daf7f17a106b3f5 upstream. The function tty_port_tty_get() gets a reference to the tty. Since the code is not using tty_port_tty_set(), the reference is kept even after closing the tty. Avoid using tty_port_tty_get() by directly access the tty instance. Since lpuart_start_rx_dma() is called from the .startup() and .set_termios() callback, it is safe to assume the tty instance is valid. Cc: stable@vger.kernel.org # v4.9+ Fixes: 5887ad43ee02 ("tty: serial: fsl_lpuart: Use cyclic DMA for Rx") Signed-off-by: Stefan Agner Signed-off-by: Greg Kroah-Hartman

drivers/tty: add error handling for pcmcia_loop_config

2018-10-04T00:00:51+00:00

[ Upstream commit 85c634e919bd6ef17427f26a52920aeba12e16ee ] When pcmcia_loop_config fails, the lack of error-handling code may cause unexpected results. This patch adds error-handling code after calling pcmcia_loop_config. Signed-off-by: Zhouyang Jia Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Stop RX FIFO timer during port shutdown

2018-10-04T00:00:46+00:00

[ Upstream commit c5a9262fa8bfed0dddc7466ef10fcd292e2af61b ] The RX FIFO timer may be armed when the port is shut down, hence the timer function may still be called afterwards. Fix this race condition by deleting the timer during port shutdown. Fixes: 039403765e5da3c6 ("serial: sh-sci: SCIFA/B RX FIFO software timeout") Signed-off-by: Geert Uytterhoeven Reviewed-by: Simon Horman Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

earlycon: Remove hardcoded port->uartclk initialization in of_setup_earlycon

2018-09-26T06:38:14+00:00

commit 182ead3e418a20328b73152b8e81fc8b4cac3b0b upstream. There is no reason to initialize uartclk to BASE_BAUD * 16 for DT based systems. [-stable comment: commit 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure") has changed 8250_early.c behavior which now tries to setup UART speed. Already-backported upstream commit 0ff3ab701963 ("serial: 8250_early: Only set divisor if valid clk & baud") handles properly uartclk not being set but it still requires backporting fix for wrong uartclk val. This fixes malformed early console output on arch-es with BASE_BAUD.] Fixes: 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure") Signed-off-by: Michal Simek Tested-by: Matt Redfearn [rmilecki: add -stable comment and Fixes tag] Signed-off-by: Rafał Miłecki Signed-off-by: Greg Kroah-Hartman

earlycon: Initialize port->uartclk based on clock-frequency property

2018-09-26T06:38:14+00:00

commit 814453adea7d081ad8917aa0f32d6a14165a3563 upstream. On DT based platforms when current-speed property is present baudrate is setup. Also port->uartclk is initialized to bogus BASE_BAUD * 16 value. Drivers like uartps/ns16550 contain logic when baudrate and uartclk is used for baudrate calculation. The patch is reading optional clock-frequency property to replace bogus BASE_BAUD * 16 calculation to have proper baudrate calculation. [-stable comment: commit 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure") has changed 8250_early.c behavior which now tries to setup UART speed. Ignoring clock-frequency results in wrong value of calculated divisor & malformed early console output.] Fixes: 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure") Signed-off-by: Michal Simek [rmilecki: add -stable comment and Fixes tag] Signed-off-by: Rafał Miłecki Signed-off-by: Greg Kroah-Hartman