2 menu "Character Devices"
8 console driver which dumps all printk messages to stderr.
15 bool "Virtual serial line"
17 The User-Mode Linux environment allows you to create virtual serial
18 lines on the UML that are usually made to show up on the host as
21 See <http://user-mode-linux.sourceforge.net/old/input.html> for more
22 information and command line examples of how to use this facility.
24 Unless you have a specific reason for disabling this, say Y.
27 bool "null channel support"
29 This option enables support for attaching UML consoles and serial
30 lines to a device similar to /dev/null. Data written to it disappears
31 and there is never any data to be read.
34 bool "port channel support"
36 This option enables support for attaching UML consoles and serial
37 lines to host portals. They may be accessed with 'telnet <host>
38 <port number>'. Any number of consoles and serial lines may be
39 attached to a single portal, although what UML device you get when
40 you telnet to that portal will be unpredictable.
41 It is safe to say 'Y' here.
44 bool "pty channel support"
46 This option enables support for attaching UML consoles and serial
47 lines to host pseudo-terminals. Access to both traditional
48 pseudo-terminals (/dev/pty*) and pts pseudo-terminals are controlled
49 with this option. The assignment of UML devices to host devices
50 will be announced in the kernel message log.
51 It is safe to say 'Y' here.
54 bool "tty channel support"
56 This option enables support for attaching UML consoles and serial
57 lines to host terminals. Access to both virtual consoles
58 (/dev/tty*) and the slave side of pseudo-terminals (/dev/ttyp* and
59 /dev/pts/*) are controlled by this option.
60 It is safe to say 'Y' here.
63 bool "xterm channel support"
65 This option enables support for attaching UML consoles and serial
66 lines to xterms. Each UML device so assigned will be brought up in
68 It is safe to say 'Y' here.
72 default !(XTERM_CHAN && TTY_CHAN && PTY_CHAN && PORT_CHAN && NULL_CHAN)
75 string "Default main console channel initialization"
78 This is the string describing the channel to which the main console
79 will be attached by default. This value can be overridden from the
80 command line. The default value is "fd:0,fd:1", which attaches the
81 main console to stdin and stdout.
82 It is safe to leave this unchanged.
85 string "Default console channel initialization"
88 This is the string describing the channel to which all consoles
89 except the main console will be attached by default. This value can
90 be overridden from the command line. The default value is "xterm",
91 which brings them up in xterms.
92 It is safe to leave this unchanged, although you may wish to change
93 this if you expect the UML that you build to be run in environments
94 which don't have X or xterm available.
97 string "Default serial line channel initialization"
100 This is the string describing the channel to which the serial lines
101 will be attached by default. This value can be overridden from the
102 command line. The default value is "pty", which attaches them to
103 traditional pseudo-terminals.
104 It is safe to leave this unchanged, although you may wish to change
105 this if you expect the UML that you build to be run in environments
106 which don't have a set of /dev/pty* devices.
109 bool "Unix98 PTY support"
111 A pseudo terminal (PTY) is a software device consisting of two
112 halves: a master and a slave. The slave device behaves identical to
113 a physical terminal; the master device is used by a process to
114 read data from and write data to the slave, thereby emulating a
115 terminal. Typical programs for the master side are telnet servers
118 Linux has traditionally used the BSD-like names /dev/ptyxx for
119 masters and /dev/ttyxx for slaves of pseudo terminals. This scheme
120 has a number of problems. The GNU C library glibc 2.1 and later,
121 however, supports the Unix98 naming standard: in order to acquire a
122 pseudo terminal, a process opens /dev/ptmx; the number of the pseudo
123 terminal is then made available to the process and the pseudo
124 terminal slave can be accessed as /dev/pts/<number>. What was
125 traditionally /dev/ttyp2 will then be /dev/pts/2, for example.
127 All modern Linux systems use the Unix98 ptys. Say Y unless
128 you're on an embedded system and want to conserve memory.
131 bool "Legacy (BSD) PTY support"
134 A pseudo terminal (PTY) is a software device consisting of two
135 halves: a master and a slave. The slave device behaves identical to
136 a physical terminal; the master device is used by a process to
137 read data from and write data to the slave, thereby emulating a
138 terminal. Typical programs for the master side are telnet servers
141 Linux has traditionally used the BSD-like names /dev/ptyxx
142 for masters and /dev/ttyxx for slaves of pseudo
143 terminals. This scheme has a number of problems, including
144 security. This option enables these legacy devices; on most
145 systems, it is safe to say N.
148 tristate "RAW driver (/dev/raw/rawN)"
151 The raw driver permits block devices to be bound to /dev/raw/rawN.
152 Once bound, I/O against /dev/raw/rawN uses efficient zero-copy I/O.
153 See the raw(8) manpage for more details.
155 Applications should preferably open the device (eg /dev/hda1)
156 with the O_DIRECT flag.
159 int "Maximum number of RAW devices to support (1-8192)"
160 depends on RAW_DRIVER
163 The maximum number of RAW devices that are supported.
164 Default is 256. Increase this number in case you need lots of
167 config LEGACY_PTY_COUNT
168 int "Maximum number of legacy PTY in use"
169 depends on LEGACY_PTYS
172 The maximum number of legacy PTYs that can be used at any one time.
173 The default is 256, and should be more than enough. Embedded
174 systems may want to reduce this to save memory.
176 When not in use, each legacy PTY occupies 12 bytes on 32-bit
177 architectures and 24 bytes on 64-bit architectures.
180 bool "Watchdog Timer Support"
182 config WATCHDOG_NOWAYOUT
183 bool "Disable watchdog shutdown on close"
187 tristate "Software Watchdog"
191 tristate "UML watchdog"
195 tristate "Sound support"
197 This option enables UML sound support. If enabled, it will pull in
198 soundcore and the UML hostaudio relay, which acts as a intermediary
199 between the host's dsp and mixer devices and the UML sound system.
200 It is safe to say 'Y' here.
210 #It is selected elsewhere, so kconfig would warn without this.
216 tristate "Hardware random number generator"
218 This option enables UML's "hardware" random number generator. It
219 attaches itself to the host's /dev/random, supplying as much entropy
220 as the host has, rather than the small amount the UML gets from its
221 own drivers. It registers itself as a standard hardware random number
222 generator, major 10, minor 183, and the canonical device name is
224 The way to make use of this is to install the rng-tools package
225 (check your distro, or download from
226 http://sourceforge.net/projects/gkernel/). rngd periodically reads
227 /dev/hwrng and injects the entropy into /dev/random.
230 tristate "iomem emulation driver"
232 This driver allows a host file to be used as emulated IO memory inside