Merge tag 'tty-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver updates from Greg KH:
 "Here is the "big" set of tty/serial driver changes for 6.2-rc1.

  As in previous kernel releases, nothing big here at all, just some
  small incremental serial/tty layer cleanups and some individual driver
  additions and fixes. Highlights are:

   - serial helper macros from Jiri Slaby to reduce the amount of
     duplicated code in serial drivers

   - api cleanups and consolidations from Ilpo Järvinen in lots of
     serial drivers

   - the usual set of n_gsm fixes from Daniel Starke as that code gets
     exercised more

   - TIOCSTI is finally able to be disabled if requested (security
     hardening feature from Kees Cook)

   - fsl_lpuart driver fixes and features added

   - other small serial driver additions and fixes

  All of these have been in linux-next for a while with no reported
  problems"

* tag 'tty-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (97 commits)
  serial: atmel: don't stop the transmitter when doing PIO
  serial: atmel: cleanup atmel_start+stop_tx()
  tty: serial: fsl_lpuart: switch to new dmaengine_terminate_* API
  serial: sunsab: Fix error handling in sunsab_init()
  serial: altera_uart: fix locking in polling mode
  serial: pch: Fix PCI device refcount leak in pch_request_dma()
  tty: serial: fsl_lpuart: Use pm_ptr() to avoid need to make pm __maybe_unused
  tty: serial: fsl_lpuart: Add runtime pm support
  tty: serial: fsl_lpuart: enable wakeup source for lpuart
  serdev: Replace poll loop by readx_poll_timeout() macro
  tty: synclink_gt: unwind actions in error path of net device open
  serial: stm32: move dma_request_chan() before clk_prepare_enable()
  dt-bindings: serial: xlnx,opb-uartlite: Drop 'contains' from 'xlnx,use-parity'
  serial: pl011: Do not clear RX FIFO & RX interrupt in unthrottle.
  serial: amba-pl011: avoid SBSA UART accessing DMACR register
  tty: serial: altera_jtaguart: remove struct altera_jtaguart
  tty: serial: altera_jtaguart: use uart_port::read_status_mask
  tty: serial: altera_jtaguart: remove unused altera_jtaguart::sigs
  tty: serial: altera_jtaguart: remove flag from altera_jtaguart_rx_chars()
  n_tty: Rename tail to old_tail in n_tty_read()
  ...

Author: torvalds

Documentation/devicetree/bindings/serial/ingenic,uart.yaml

@@ -20,6 +20,7 @@ properties:
     oneOf:
       - enum:
           - ingenic,jz4740-uart
+          - ingenic,jz4750-uart
           - ingenic,jz4760-uart
           - ingenic,jz4780-uart
           - ingenic,x1000-uart
@@ -31,6 +32,9 @@ properties:
       - items:
           - const: ingenic,jz4725b-uart
           - const: ingenic,jz4740-uart
+      - items:
+          - const: ingenic,jz4755-uart
+          - const: ingenic,jz4750-uart
 
   reg:
     maxItems: 1

Documentation/devicetree/bindings/serial/renesas,scif.yaml

@@ -67,6 +67,7 @@ properties:
           - enum:
               - renesas,scif-r8a779a0     # R-Car V3U
               - renesas,scif-r8a779f0     # R-Car S4-8
+              - renesas,scif-r8a779g0     # R-Car V4H
           - const: renesas,rcar-gen4-scif # R-Car Gen4
           - const: renesas,scif           # generic SCIF compatible UART
 

Documentation/devicetree/bindings/serial/xlnx,opb-uartlite.yaml

@@ -67,8 +67,7 @@ allOf:
   - if:
       properties:
         xlnx,use-parity:
-          contains:
-            const: 1
+          const: 1
     then:
       required:
         - xlnx,odd-parity

Documentation/driver-api/serial/driver.rst

@@ -78,6 +78,9 @@ Other functions
            uart_get_lsr_info uart_handle_dcd_change uart_handle_cts_change
            uart_try_toggle_sysrq uart_get_console
 
+.. kernel-doc:: include/linux/serial_core.h
+   :identifiers: uart_port_tx_limited uart_port_tx
+
 Other notes
 -----------
 

Documentation/driver-api/serial/serial-rs485.rst

@@ -29,23 +29,28 @@ RS485 Serial Communications
 3. Data Structures Already Available in the Kernel
 ==================================================
 
-   The Linux kernel provides the serial_rs485 structure (see [1]) to handle
-   RS485 communications. This data structure is used to set and configure RS485
+   The Linux kernel provides the struct serial_rs485 to handle RS485
+   communications. This data structure is used to set and configure RS485
    parameters in the platform data and in ioctls.
 
-   The device tree can also provide RS485 boot time parameters (see [2]
-   for bindings). The driver is in charge of filling this data structure from
-   the values given by the device tree.
+   The device tree can also provide RS485 boot time parameters
+   [#DT-bindings]_. The serial core fills the struct serial_rs485 from the
+   values given by the device tree when the driver calls
+   uart_get_rs485_mode().
 
    Any driver for devices capable of working both as RS232 and RS485 should
-   implement the rs485_config callback and provide rs485_supported in the
-   uart_port structure. The serial core calls rs485_config to do the device
-   specific part in response to TIOCSRS485 ioctl (see below). The rs485_config
-   callback receives a pointer to a sanitizated serial_rs485 structure. The
-   serial_rs485 userspace provides is sanitized before calling rs485_config
-   using rs485_supported that indicates what RS485 features the driver supports
-   for the uart_port. TIOCGRS485 ioctl can be used to read back the
-   serial_rs485 structure matching to the current configuration.
+   implement the ``rs485_config`` callback and provide ``rs485_supported``
+   in the ``struct uart_port``. The serial core calls ``rs485_config`` to do
+   the device specific part in response to TIOCSRS485 ioctl (see below). The
+   ``rs485_config`` callback receives a pointer to a sanitizated struct
+   serial_rs485. The struct serial_rs485 userspace provides is sanitized
+   before calling ``rs485_config`` using ``rs485_supported`` that indicates
+   what RS485 features the driver supports for the ``struct uart_port``.
+   TIOCGRS485 ioctl can be used to read back the struct serial_rs485
+   matching to the current configuration.
+
+.. kernel-doc:: include/uapi/linux/serial.h
+   :identifiers: serial_rs485 uart_get_rs485_mode
 
 4. Usage from user-level
 ========================
@@ -103,29 +108,28 @@ RS485 Serial Communications
 ========================
 
    The Linux kernel provides addressing mode for multipoint RS-485 serial
-   communications line. The addressing mode is enabled with SER_RS485_ADDRB
-   flag in serial_rs485. Struct serial_rs485 has two additional flags and
-   fields for enabling receive and destination addresses.
+   communications line. The addressing mode is enabled with
+   ``SER_RS485_ADDRB`` flag in struct serial_rs485. The struct serial_rs485
+   has two additional flags and fields for enabling receive and destination
+   addresses.
 
    Address mode flags:
-	- SER_RS485_ADDRB: Enabled addressing mode (sets also ADDRB in termios).
-	- SER_RS485_ADDR_RECV: Receive (filter) address enabled.
-	- SER_RS485_ADDR_DEST: Set destination address.
+	- ``SER_RS485_ADDRB``: Enabled addressing mode (sets also ADDRB in termios).
+	- ``SER_RS485_ADDR_RECV``: Receive (filter) address enabled.
+	- ``SER_RS485_ADDR_DEST``: Set destination address.
 
-   Address fields (enabled with corresponding SER_RS485_ADDR_* flag):
-	- addr_recv: Receive address.
-	- addr_dest: Destination address.
+   Address fields (enabled with corresponding ``SER_RS485_ADDR_*`` flag):
+	- ``addr_recv``: Receive address.
+	- ``addr_dest``: Destination address.
 
    Once a receive address is set, the communication can occur only with the
    particular device and other peers are filtered out. It is left up to the
    receiver side to enforce the filtering. Receive address will be cleared
-   if SER_RS485_ADDR_RECV is not set.
+   if ``SER_RS485_ADDR_RECV`` is not set.
 
    Note: not all devices supporting RS485 support multipoint addressing.
 
 6. References
 =============
 
- [1]	include/uapi/linux/serial.h
-
- [2]	Documentation/devicetree/bindings/serial/rs485.txt
+.. [#DT-bindings]	Documentation/devicetree/bindings/serial/rs485.txt

drivers/tty/Kconfig

@@ -149,6 +149,25 @@ config LEGACY_PTY_COUNT
 	  When not in use, each legacy PTY occupies 12 bytes on 32-bit
 	  architectures and 24 bytes on 64-bit architectures.
 
+config LEGACY_TIOCSTI
+	bool "Allow legacy TIOCSTI usage"
+	default y
+	help
+	  Historically the kernel has allowed TIOCSTI, which will push
+	  characters into a controlling TTY. This continues to be used
+	  as a malicious privilege escalation mechanism, and provides no
+	  meaningful real-world utility any more. Its use is considered
+	  a dangerous legacy operation, and can be disabled on most
+	  systems.
+
+	  Say 'Y here only if you have confirmed that your system's
+	  userspace depends on this functionality to continue operating
+	  normally.
+
+	  This functionality can be changed at runtime with the
+	  dev.tty.legacy_tiocsti sysctl. This configuration option sets
+	  the default value of the sysctl.
+
 config LDISC_AUTOLOAD
 	bool "Automatically load TTY Line Disciplines"
 	default y

drivers/tty/ehv_bytechan.c

@@ -118,7 +118,7 @@ static int find_console_handle(void)
 		return 0;
 
 	stdout_irq = irq_of_parse_and_map(np, 0);
-	if (stdout_irq == NO_IRQ) {
+	if (!stdout_irq) {
 		pr_err("ehv-bc: no 'interrupts' property in %pOF node\n", np);
 		return 0;
 	}
@@ -696,7 +696,7 @@ static int ehv_bc_tty_probe(struct platform_device *pdev)
 
 	bc->rx_irq = irq_of_parse_and_map(np, 0);
 	bc->tx_irq = irq_of_parse_and_map(np, 1);
-	if ((bc->rx_irq == NO_IRQ) || (bc->tx_irq == NO_IRQ)) {
+	if (!bc->rx_irq || !bc->tx_irq) {
 		dev_err(&pdev->dev, "no 'interrupts' property in %pOFn node\n",
 			np);
 		ret = -ENODEV;

drivers/tty/hvc/hvc_rtas.c

@@ -26,7 +26,7 @@
 #include "hvc_console.h"
 
 #define hvc_rtas_cookie 0x67781e15
-struct hvc_struct *hvc_rtas_dev;
+static struct hvc_struct *hvc_rtas_dev;
 
 static int rtascons_put_char_token = RTAS_UNKNOWN_SERVICE;
 static int rtascons_get_char_token = RTAS_UNKNOWN_SERVICE;