tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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/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 If you disable this option, then CONFIG_PT_PROXY will be disabled as
69 well, since UML's gdb currently requires an xterm.
70 It is safe to say 'Y' here.
71
72config NOCONFIG_CHAN
73 bool
74 default !(XTERM_CHAN && TTY_CHAN && PTY_CHAN && PORT_CHAN && NULL_CHAN)
75
76config CON_ZERO_CHAN
77 string "Default main console channel initialization"
78 default "fd:0,fd:1"
79 help
80 This is the string describing the channel to which the main console
81 will be attached by default. This value can be overridden from the
82 command line. The default value is "fd:0,fd:1", which attaches the
83 main console to stdin and stdout.
84 It is safe to leave this unchanged.
85
86config CON_CHAN
87 string "Default console channel initialization"
88 default "xterm"
89 help
90 This is the string describing the channel to which all consoles
91 except the main console will be attached by default. This value can
92 be overridden from the command line. The default value is "xterm",
93 which brings them up in xterms.
94 It is safe to leave this unchanged, although you may wish to change
95 this if you expect the UML that you build to be run in environments
96 which don't have X or xterm available.
97
98config SSL_CHAN
99 string "Default serial line channel initialization"
100 default "pty"
101 help
102 This is the string describing the channel to which the serial lines
103 will be attached by default. This value can be overridden from the
104 command line. The default value is "pty", which attaches them to
105 traditional pseudo-terminals.
106 It is safe to leave this unchanged, although you may wish to change
107 this if you expect the UML that you build to be run in environments
108 which don't have a set of /dev/pty* devices.
109
110config UNIX98_PTYS
111 bool "Unix98 PTY support"
112 ---help---
113 A pseudo terminal (PTY) is a software device consisting of two
114 halves: a master and a slave. The slave device behaves identical to
115 a physical terminal; the master device is used by a process to
116 read data from and write data to the slave, thereby emulating a
117 terminal. Typical programs for the master side are telnet servers
118 and xterms.
119
120 Linux has traditionally used the BSD-like names /dev/ptyxx for
121 masters and /dev/ttyxx for slaves of pseudo terminals. This scheme
122 has a number of problems. The GNU C library glibc 2.1 and later,
123 however, supports the Unix98 naming standard: in order to acquire a
124 pseudo terminal, a process opens /dev/ptmx; the number of the pseudo
125 terminal is then made available to the process and the pseudo
126 terminal slave can be accessed as /dev/pts/<number>. What was
127 traditionally /dev/ttyp2 will then be /dev/pts/2, for example.
128
129 All modern Linux systems use the Unix98 ptys. Say Y unless
130 you're on an embedded system and want to conserve memory.
131
132config LEGACY_PTYS
133 bool "Legacy (BSD) PTY support"
134 default y
135 ---help---
136 A pseudo terminal (PTY) is a software device consisting of two
137 halves: a master and a slave. The slave device behaves identical to
138 a physical terminal; the master device is used by a process to
139 read data from and write data to the slave, thereby emulating a
140 terminal. Typical programs for the master side are telnet servers
141 and xterms.
142
143 Linux has traditionally used the BSD-like names /dev/ptyxx
144 for masters and /dev/ttyxx for slaves of pseudo
145 terminals. This scheme has a number of problems, including
146 security. This option enables these legacy devices; on most
147 systems, it is safe to say N.
148
149
150config LEGACY_PTY_COUNT
151 int "Maximum number of legacy PTY in use"
152 depends on LEGACY_PTYS
153 default "256"
154 ---help---
155 The maximum number of legacy PTYs that can be used at any one time.
156 The default is 256, and should be more than enough. Embedded
157 systems may want to reduce this to save memory.
158
159 When not in use, each legacy PTY occupies 12 bytes on 32-bit
160 architectures and 24 bytes on 64-bit architectures.
161
162config WATCHDOG
163 bool "Watchdog Timer Support"
164
165config WATCHDOG_NOWAYOUT
166 bool "Disable watchdog shutdown on close"
167 depends on WATCHDOG
168
169config SOFT_WATCHDOG
170 tristate "Software Watchdog"
171 depends on WATCHDOG
172
173config UML_WATCHDOG
174 tristate "UML watchdog"
175 depends on WATCHDOG
176
177config UML_SOUND
178 tristate "Sound support"
179 help
180 This option enables UML sound support. If enabled, it will pull in
181 soundcore and the UML hostaudio relay, which acts as a intermediary
182 between the host's dsp and mixer devices and the UML sound system.
183 It is safe to say 'Y' here.
184
185config SOUND
186 tristate
187 default UML_SOUND
188
189config HOSTAUDIO
190 tristate
191 default UML_SOUND
192
193#It is selected elsewhere, so kconfig would warn without this.
194config HW_RANDOM
195 tristate
196 default n
197
198config UML_RANDOM
199 tristate "Hardware random number generator"
200 help
201 This option enables UML's "hardware" random number generator. It
202 attaches itself to the host's /dev/random, supplying as much entropy
203 as the host has, rather than the small amount the UML gets from its
204 own drivers. It registers itself as a standard hardware random number
205 generator, major 10, minor 183, and the canonical device name is
206 /dev/hwrng.
207 The way to make use of this is to install the rng-tools package
208 (check your distro, or download from
209 http://sourceforge.net/projects/gkernel/). rngd periodically reads
210 /dev/hwrng and injects the entropy into /dev/random.
211
212config MMAPPER
213 tristate "iomem emulation driver"
214 help
215 This driver allows a host file to be used as emulated IO memory inside
216 UML.
217
218endmenu
219