v4.19.13 snapshot.
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
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+# SPDX-License-Identifier: GPL-2.0
+#
+# Character device configuration
+#
+
+menu "Character devices"
+
+source "drivers/tty/Kconfig"
+
+config DEVMEM
+ bool "/dev/mem virtual device support"
+ default y
+ help
+ Say Y here if you want to support the /dev/mem device.
+ The /dev/mem device is used to access areas of physical
+ memory.
+ When in doubt, say "Y".
+
+config DEVKMEM
+ bool "/dev/kmem virtual device support"
+ # On arm64, VMALLOC_START < PAGE_OFFSET, which confuses kmem read/write
+ depends on !ARM64
+ help
+ Say Y here if you want to support the /dev/kmem device. The
+ /dev/kmem device is rarely used, but can be used for certain
+ kind of kernel debugging operations.
+ When in doubt, say "N".
+
+config SGI_SNSC
+ bool "SGI Altix system controller communication support"
+ depends on (IA64_SGI_SN2 || IA64_GENERIC)
+ help
+ If you have an SGI Altix and you want to enable system
+ controller communication from user space (you want this!),
+ say Y. Otherwise, say N.
+
+config SGI_TIOCX
+ bool "SGI TIO CX driver support"
+ depends on (IA64_SGI_SN2 || IA64_GENERIC)
+ help
+ If you have an SGI Altix and you have fpga devices attached
+ to your TIO, say Y here, otherwise say N.
+
+config SGI_MBCS
+ tristate "SGI FPGA Core Services driver support"
+ depends on SGI_TIOCX
+ help
+ If you have an SGI Altix with an attached SABrick
+ say Y or M here, otherwise say N.
+
+source "drivers/tty/serial/Kconfig"
+source "drivers/tty/serdev/Kconfig"
+
+config TTY_PRINTK
+ tristate "TTY driver to output user messages via printk"
+ depends on EXPERT && TTY
+ default n
+ ---help---
+ If you say Y here, the support for writing user messages (i.e.
+ console messages) via printk is available.
+
+ The feature is useful to inline user messages with kernel
+ messages.
+ In order to use this feature, you should output user messages
+ to /dev/ttyprintk or redirect console to this TTY.
+
+ If unsure, say N.
+
+config PRINTER
+ tristate "Parallel printer support"
+ depends on PARPORT
+ ---help---
+ If you intend to attach a printer to the parallel port of your Linux
+ box (as opposed to using a serial printer; if the connector at the
+ printer has 9 or 25 holes ["female"], then it's serial), say Y.
+ Also read the Printing-HOWTO, available from
+ <http://www.tldp.org/docs.html#howto>.
+
+ It is possible to share one parallel port among several devices
+ (e.g. printer and ZIP drive) and it is safe to compile the
+ corresponding drivers into the kernel.
+
+ To compile this driver as a module, choose M here and read
+ <file:Documentation/admin-guide/parport.rst>. The module will be called lp.
+
+ If you have several parallel ports, you can specify which ports to
+ use with the "lp" kernel command line option. (Try "man bootparam"
+ or see the documentation of your boot loader (lilo or loadlin) about
+ how to pass options to the kernel at boot time.) The syntax of the
+ "lp" command line option can be found in <file:drivers/char/lp.c>.
+
+ If you have more than 8 printers, you need to increase the LP_NO
+ macro in lp.c and the PARPORT_MAX macro in parport.h.
+
+config LP_CONSOLE
+ bool "Support for console on line printer"
+ depends on PRINTER
+ ---help---
+ If you want kernel messages to be printed out as they occur, you
+ can have a console on the printer. This option adds support for
+ doing that; to actually get it to happen you need to pass the
+ option "console=lp0" to the kernel at boot time.
+
+ If the printer is out of paper (or off, or unplugged, or too
+ busy..) the kernel will stall until the printer is ready again.
+ By defining CONSOLE_LP_STRICT to 0 (at your own risk) you
+ can make the kernel continue when this happens,
+ but it'll lose the kernel messages.
+
+ If unsure, say N.
+
+config PPDEV
+ tristate "Support for user-space parallel port device drivers"
+ depends on PARPORT
+ ---help---
+ Saying Y to this adds support for /dev/parport device nodes. This
+ is needed for programs that want portable access to the parallel
+ port, for instance deviceid (which displays Plug-and-Play device
+ IDs).
+
+ This is the parallel port equivalent of SCSI generic support (sg).
+ It is safe to say N to this -- it is not needed for normal printing
+ or parallel port CD-ROM/disk support.
+
+ To compile this driver as a module, choose M here: the
+ module will be called ppdev.
+
+ If unsure, say N.
+
+source "drivers/tty/hvc/Kconfig"
+
+config VIRTIO_CONSOLE
+ tristate "Virtio console"
+ depends on VIRTIO && TTY
+ select HVC_DRIVER
+ help
+ Virtio console for use with hypervisors.
+
+ Also serves as a general-purpose serial device for data
+ transfer between the guest and host. Character devices at
+ /dev/vportNpn will be created when corresponding ports are
+ found, where N is the device number and n is the port number
+ within that device. If specified by the host, a sysfs
+ attribute called 'name' will be populated with a name for
+ the port which can be used by udev scripts to create a
+ symlink to the device.
+
+config IBM_BSR
+ tristate "IBM POWER Barrier Synchronization Register support"
+ depends on PPC_PSERIES
+ help
+ This devices exposes a hardware mechanism for fast synchronization
+ of threads across a large system which avoids bouncing a cacheline
+ between several cores on a system
+
+config POWERNV_OP_PANEL
+ tristate "IBM POWERNV Operator Panel Display support"
+ depends on PPC_POWERNV
+ default m
+ help
+ If you say Y here, a special character device node, /dev/op_panel,
+ will be created which exposes the operator panel display on IBM
+ Power Systems machines with FSPs.
+
+ If you don't require access to the operator panel display from user
+ space, say N.
+
+ If unsure, say M here to build it as a module called powernv-op-panel.
+
+source "drivers/char/ipmi/Kconfig"
+
+config DS1620
+ tristate "NetWinder thermometer support"
+ depends on ARCH_NETWINDER
+ help
+ Say Y here to include support for the thermal management hardware
+ found in the NetWinder. This driver allows the user to control the
+ temperature set points and to read the current temperature.
+
+ It is also possible to say M here to build it as a module (ds1620)
+ It is recommended to be used on a NetWinder, but it is not a
+ necessity.
+
+config NWBUTTON
+ tristate "NetWinder Button"
+ depends on ARCH_NETWINDER
+ ---help---
+ If you say Y here and create a character device node /dev/nwbutton
+ with major and minor numbers 10 and 158 ("man mknod"), then every
+ time the orange button is pressed a number of times, the number of
+ times the button was pressed will be written to that device.
+
+ This is most useful for applications, as yet unwritten, which
+ perform actions based on how many times the button is pressed in a
+ row.
+
+ Do not hold the button down for too long, as the driver does not
+ alter the behaviour of the hardware reset circuitry attached to the
+ button; it will still execute a hard reset if the button is held
+ down for longer than approximately five seconds.
+
+ To compile this driver as a module, choose M here: the
+ module will be called nwbutton.
+
+ Most people will answer Y to this question and "Reboot Using Button"
+ below to be able to initiate a system shutdown from the button.
+
+config NWBUTTON_REBOOT
+ bool "Reboot Using Button"
+ depends on NWBUTTON
+ help
+ If you say Y here, then you will be able to initiate a system
+ shutdown and reboot by pressing the orange button a number of times.
+ The number of presses to initiate the shutdown is two by default,
+ but this can be altered by modifying the value of NUM_PRESSES_REBOOT
+ in nwbutton.h and recompiling the driver or, if you compile the
+ driver as a module, you can specify the number of presses at load
+ time with "insmod button reboot_count=<something>".
+
+config NWFLASH
+ tristate "NetWinder flash support"
+ depends on ARCH_NETWINDER
+ ---help---
+ If you say Y here and create a character device /dev/flash with
+ major 10 and minor 160 you can manipulate the flash ROM containing
+ the NetWinder firmware. Be careful as accidentally overwriting the
+ flash contents can render your computer unbootable. On no account
+ allow random users access to this device. :-)
+
+ To compile this driver as a module, choose M here: the
+ module will be called nwflash.
+
+ If you're not sure, say N.
+
+source "drivers/char/hw_random/Kconfig"
+
+config NVRAM
+ tristate "/dev/nvram support"
+ depends on ATARI || X86 || GENERIC_NVRAM
+ ---help---
+ If you say Y here and create a character special file /dev/nvram
+ with major number 10 and minor number 144 using mknod ("man mknod"),
+ you get read and write access to the extra bytes of non-volatile
+ memory in the real time clock (RTC), which is contained in every PC
+ and most Ataris. The actual number of bytes varies, depending on the
+ nvram in the system, but is usually 114 (128-14 for the RTC).
+
+ This memory is conventionally called "CMOS RAM" on PCs and "NVRAM"
+ on Ataris. /dev/nvram may be used to view settings there, or to
+ change them (with some utility). It could also be used to frequently
+ save a few bits of very important data that may not be lost over
+ power-off and for which writing to disk is too insecure. Note
+ however that most NVRAM space in a PC belongs to the BIOS and you
+ should NEVER idly tamper with it. See Ralf Brown's interrupt list
+ for a guide to the use of CMOS bytes by your BIOS.
+
+ On Atari machines, /dev/nvram is always configured and does not need
+ to be selected.
+
+ To compile this driver as a module, choose M here: the
+ module will be called nvram.
+
+#
+# These legacy RTC drivers just cause too many conflicts with the generic
+# RTC framework ... let's not even try to coexist any more.
+#
+if RTC_LIB=n
+
+config RTC
+ tristate "Enhanced Real Time Clock Support (legacy PC RTC driver)"
+ depends on ALPHA || (MIPS && MACH_LOONGSON64)
+ ---help---
+ If you say Y here and create a character special file /dev/rtc with
+ major number 10 and minor number 135 using mknod ("man mknod"), you
+ will get access to the real time clock (or hardware clock) built
+ into your computer.
+
+ Every PC has such a clock built in. It can be used to generate
+ signals from as low as 1Hz up to 8192Hz, and can also be used
+ as a 24 hour alarm. It reports status information via the file
+ /proc/driver/rtc and its behaviour is set by various ioctls on
+ /dev/rtc.
+
+ If you run Linux on a multiprocessor machine and said Y to
+ "Symmetric Multi Processing" above, you should say Y here to read
+ and set the RTC in an SMP compatible fashion.
+
+ If you think you have a use for such a device (such as periodic data
+ sampling), then say Y here, and read <file:Documentation/rtc.txt>
+ for details.
+
+ To compile this driver as a module, choose M here: the
+ module will be called rtc.
+
+config JS_RTC
+ tristate "Enhanced Real Time Clock Support"
+ depends on SPARC32 && PCI
+ ---help---
+ If you say Y here and create a character special file /dev/rtc with
+ major number 10 and minor number 135 using mknod ("man mknod"), you
+ will get access to the real time clock (or hardware clock) built
+ into your computer.
+
+ Every PC has such a clock built in. It can be used to generate
+ signals from as low as 1Hz up to 8192Hz, and can also be used
+ as a 24 hour alarm. It reports status information via the file
+ /proc/driver/rtc and its behaviour is set by various ioctls on
+ /dev/rtc.
+
+ If you think you have a use for such a device (such as periodic data
+ sampling), then say Y here, and read <file:Documentation/rtc.txt>
+ for details.
+
+ To compile this driver as a module, choose M here: the
+ module will be called js-rtc.
+
+config EFI_RTC
+ bool "EFI Real Time Clock Services"
+ depends on IA64
+
+endif # RTC_LIB
+
+config DTLK
+ tristate "Double Talk PC internal speech card support"
+ depends on ISA
+ help
+ This driver is for the DoubleTalk PC, a speech synthesizer
+ manufactured by RC Systems (<http://www.rcsys.com/>). It is also
+ called the `internal DoubleTalk'.
+
+ To compile this driver as a module, choose M here: the
+ module will be called dtlk.
+
+config XILINX_HWICAP
+ tristate "Xilinx HWICAP Support"
+ depends on XILINX_VIRTEX || MICROBLAZE
+ help
+ This option enables support for Xilinx Internal Configuration
+ Access Port (ICAP) driver. The ICAP is used on Xilinx Virtex
+ FPGA platforms to partially reconfigure the FPGA at runtime.
+
+ If unsure, say N.
+
+config R3964
+ tristate "Siemens R3964 line discipline"
+ depends on TTY
+ ---help---
+ This driver allows synchronous communication with devices using the
+ Siemens R3964 packet protocol. Unless you are dealing with special
+ hardware like PLCs, you are unlikely to need this.
+
+ To compile this driver as a module, choose M here: the
+ module will be called n_r3964.
+
+ If unsure, say N.
+
+config APPLICOM
+ tristate "Applicom intelligent fieldbus card support"
+ depends on PCI
+ ---help---
+ This driver provides the kernel-side support for the intelligent
+ fieldbus cards made by Applicom International. More information
+ about these cards can be found on the WWW at the address
+ <http://www.applicom-int.com/>, or by email from David Woodhouse
+ <dwmw2@infradead.org>.
+
+ To compile this driver as a module, choose M here: the
+ module will be called applicom.
+
+ If unsure, say N.
+
+config SONYPI
+ tristate "Sony Vaio Programmable I/O Control Device support"
+ depends on X86_32 && PCI && INPUT
+ ---help---
+ This driver enables access to the Sony Programmable I/O Control
+ Device which can be found in many (all ?) Sony Vaio laptops.
+
+ If you have one of those laptops, read
+ <file:Documentation/laptops/sonypi.txt>, and say Y or M here.
+
+ To compile this driver as a module, choose M here: the
+ module will be called sonypi.
+
+config GPIO_TB0219
+ tristate "TANBAC TB0219 GPIO support"
+ depends on TANBAC_TB022X
+ select GPIO_VR41XX
+
+source "drivers/char/pcmcia/Kconfig"
+
+config MWAVE
+ tristate "ACP Modem (Mwave) support"
+ depends on X86 && TTY
+ select SERIAL_8250
+ ---help---
+ The ACP modem (Mwave) for Linux is a WinModem. It is composed of a
+ kernel driver and a user level application. Together these components
+ support direct attachment to public switched telephone networks (PSTNs)
+ and support selected world wide countries.
+
+ This version of the ACP Modem driver supports the IBM Thinkpad 600E,
+ 600, and 770 that include on board ACP modem hardware.
+
+ The modem also supports the standard communications port interface
+ (ttySx) and is compatible with the Hayes AT Command Set.
+
+ The user level application needed to use this driver can be found at
+ the IBM Linux Technology Center (LTC) web site:
+ <http://www.ibm.com/linux/ltc/>.
+
+ If you own one of the above IBM Thinkpads which has the Mwave chipset
+ in it, say Y.
+
+ To compile this driver as a module, choose M here: the
+ module will be called mwave.
+
+config SCx200_GPIO
+ tristate "NatSemi SCx200 GPIO Support"
+ depends on SCx200
+ select NSC_GPIO
+ help
+ Give userspace access to the GPIO pins on the National
+ Semiconductor SCx200 processors.
+
+ If compiled as a module, it will be called scx200_gpio.
+
+config PC8736x_GPIO
+ tristate "NatSemi PC8736x GPIO Support"
+ depends on X86_32 && !UML
+ default SCx200_GPIO # mostly N
+ select NSC_GPIO # needed for support routines
+ help
+ Give userspace access to the GPIO pins on the National
+ Semiconductor PC-8736x (x=[03456]) SuperIO chip. The chip
+ has multiple functional units, inc several managed by
+ hwmon/pc87360 driver. Tested with PC-87366
+
+ If compiled as a module, it will be called pc8736x_gpio.
+
+config NSC_GPIO
+ tristate "NatSemi Base GPIO Support"
+ depends on X86_32
+ # selected by SCx200_GPIO and PC8736x_GPIO
+ # what about 2 selectors differing: m != y
+ help
+ Common support used (and needed) by scx200_gpio and
+ pc8736x_gpio drivers. If those drivers are built as
+ modules, this one will be too, named nsc_gpio
+
+config RAW_DRIVER
+ tristate "RAW driver (/dev/raw/rawN)"
+ depends on BLOCK
+ help
+ The raw driver permits block devices to be bound to /dev/raw/rawN.
+ Once bound, I/O against /dev/raw/rawN uses efficient zero-copy I/O.
+ See the raw(8) manpage for more details.
+
+ Applications should preferably open the device (eg /dev/hda1)
+ with the O_DIRECT flag.
+
+config MAX_RAW_DEVS
+ int "Maximum number of RAW devices to support (1-65536)"
+ depends on RAW_DRIVER
+ range 1 65536
+ default "256"
+ help
+ The maximum number of RAW devices that are supported.
+ Default is 256. Increase this number in case you need lots of
+ raw devices.
+
+config HPET
+ bool "HPET - High Precision Event Timer" if (X86 || IA64)
+ default n
+ depends on ACPI
+ help
+ If you say Y here, you will have a miscdevice named "/dev/hpet/". Each
+ open selects one of the timers supported by the HPET. The timers are
+ non-periodic and/or periodic.
+
+config HPET_MMAP
+ bool "Allow mmap of HPET"
+ default y
+ depends on HPET
+ help
+ If you say Y here, user applications will be able to mmap
+ the HPET registers.
+
+config HPET_MMAP_DEFAULT
+ bool "Enable HPET MMAP access by default"
+ default y
+ depends on HPET_MMAP
+ help
+ In some hardware implementations, the page containing HPET
+ registers may also contain other things that shouldn't be
+ exposed to the user. This option selects the default (if
+ kernel parameter hpet_mmap is not set) user access to the
+ registers for applications that require it.
+
+config HANGCHECK_TIMER
+ tristate "Hangcheck timer"
+ depends on X86 || IA64 || PPC64 || S390
+ help
+ The hangcheck-timer module detects when the system has gone
+ out to lunch past a certain margin. It can reboot the system
+ or merely print a warning.
+
+config UV_MMTIMER
+ tristate "UV_MMTIMER Memory mapped RTC for SGI UV"
+ depends on X86_UV
+ default m
+ help
+ The uv_mmtimer device allows direct userspace access to the
+ UV system timer.
+
+source "drivers/char/tpm/Kconfig"
+
+config TELCLOCK
+ tristate "Telecom clock driver for ATCA SBC"
+ depends on X86
+ default n
+ help
+ The telecom clock device is specific to the MPCBL0010 and MPCBL0050
+ ATCA computers and allows direct userspace access to the
+ configuration of the telecom clock configuration settings. This
+ device is used for hardware synchronization across the ATCA backplane
+ fabric. Upon loading, the driver exports a sysfs directory,
+ /sys/devices/platform/telco_clock, with a number of files for
+ controlling the behavior of this hardware.
+
+config DEVPORT
+ bool "/dev/port character device"
+ depends on ISA || PCI
+ default y
+ help
+ Say Y here if you want to support the /dev/port device. The /dev/port
+ device is similar to /dev/mem, but for I/O ports.
+
+source "drivers/s390/char/Kconfig"
+
+source "drivers/char/xillybus/Kconfig"
+
+config ADI
+ tristate "SPARC Privileged ADI driver"
+ depends on SPARC64
+ default m
+ help
+ SPARC M7 and newer processors utilize ADI (Application Data
+ Integrity) to version and protect memory. This driver provides
+ read/write access to the ADI versions for privileged processes.
+ This feature is also known as MCD (Memory Corruption Detection)
+ and SSM (Silicon Secured Memory). Intended consumers of this
+ driver include crash and makedumpfile.
+
+endmenu
+
+config RANDOM_TRUST_CPU
+ bool "Trust the CPU manufacturer to initialize Linux's CRNG"
+ depends on X86 || S390 || PPC
+ default n
+ help
+ Assume that CPU manufacturer (e.g., Intel or AMD for RDSEED or
+ RDRAND, IBM for the S390 and Power PC architectures) is trustworthy
+ for the purposes of initializing Linux's CRNG. Since this is not
+ something that can be independently audited, this amounts to trusting
+ that CPU manufacturer (perhaps with the insistence or mandate
+ of a Nation State's intelligence or law enforcement agencies)
+ has not installed a hidden back door to compromise the CPU's
+ random number generation facilities. This can also be configured
+ at boot with "random.trust_cpu=on/off".