Root/arch/um/Kconfig.char

1
2menu "Character Devices"
3
4config STDERR_CONSOLE
5    bool "stderr console"
6    default y
7    help
8      console driver which dumps all printk messages to stderr.
9
10config STDIO_CONSOLE
11    bool
12    default y
13
14config SSL
15    bool "Virtual serial line"
16    help
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
19          ttys or ptys.
20
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.
23
24          Unless you have a specific reason for disabling this, say Y.
25
26config NULL_CHAN
27    bool "null channel support"
28    help
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.
32
33config PORT_CHAN
34    bool "port channel support"
35    help
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.
42
43config PTY_CHAN
44    bool "pty channel support"
45    help
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.
52
53config TTY_CHAN
54    bool "tty channel support"
55    help
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.
61
62config XTERM_CHAN
63    bool "xterm channel support"
64    help
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
67          its own xterm.
68          It is safe to say 'Y' here.
69
70config NOCONFIG_CHAN
71    bool
72    default !(XTERM_CHAN && TTY_CHAN && PTY_CHAN && PORT_CHAN && NULL_CHAN)
73
74config CON_ZERO_CHAN
75    string "Default main console channel initialization"
76    default "fd:0,fd:1"
77    help
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.
83
84config CON_CHAN
85    string "Default console channel initialization"
86    default "xterm"
87    help
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.
95
96config SSL_CHAN
97    string "Default serial line channel initialization"
98    default "pty"
99    help
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.
107
108config UNIX98_PTYS
109    bool "Unix98 PTY support"
110    help
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
116      and xterms.
117
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.
126
127      All modern Linux systems use the Unix98 ptys. Say Y unless
128      you're on an embedded system and want to conserve memory.
129
130config LEGACY_PTYS
131    bool "Legacy (BSD) PTY support"
132    default y
133    help
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
139      and xterms.
140
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.
146
147config RAW_DRIVER
148        tristate "RAW driver (/dev/raw/rawN)"
149    depends on BLOCK
150        help
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.
154
155          Applications should preferably open the device (eg /dev/hda1)
156          with the O_DIRECT flag.
157
158config MAX_RAW_DEVS
159        int "Maximum number of RAW devices to support (1-8192)"
160        depends on RAW_DRIVER
161        default "256"
162        help
163          The maximum number of RAW devices that are supported.
164          Default is 256. Increase this number in case you need lots of
165          raw devices.
166
167config LEGACY_PTY_COUNT
168    int "Maximum number of legacy PTY in use"
169    depends on LEGACY_PTYS
170    default "256"
171    help
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.
175
176      When not in use, each legacy PTY occupies 12 bytes on 32-bit
177      architectures and 24 bytes on 64-bit architectures.
178
179config WATCHDOG
180    bool "Watchdog Timer Support"
181
182config WATCHDOG_NOWAYOUT
183    bool "Disable watchdog shutdown on close"
184    depends on WATCHDOG
185
186config SOFT_WATCHDOG
187    tristate "Software Watchdog"
188    depends on WATCHDOG
189
190config UML_WATCHDOG
191    tristate "UML watchdog"
192    depends on WATCHDOG
193
194config UML_SOUND
195    tristate "Sound support"
196    help
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.
201
202config SOUND
203    tristate
204    default UML_SOUND
205
206config SOUND_OSS_CORE
207    bool
208    default UML_SOUND
209
210config HOSTAUDIO
211    tristate
212    default UML_SOUND
213
214#It is selected elsewhere, so kconfig would warn without this.
215config HW_RANDOM
216    tristate
217    default n
218
219config UML_RANDOM
220    tristate "Hardware random number generator"
221    help
222      This option enables UML's "hardware" random number generator. It
223      attaches itself to the host's /dev/random, supplying as much entropy
224      as the host has, rather than the small amount the UML gets from its
225      own drivers. It registers itself as a standard hardware random number
226      generator, major 10, minor 183, and the canonical device name is
227      /dev/hwrng.
228      The way to make use of this is to install the rng-tools package
229      (check your distro, or download from
230      http://sourceforge.net/projects/gkernel/). rngd periodically reads
231      /dev/hwrng and injects the entropy into /dev/random.
232
233config MMAPPER
234    tristate "iomem emulation driver"
235    help
236      This driver allows a host file to be used as emulated IO memory inside
237      UML.
238
239endmenu
240

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