1 # UML uses the generic IRQ sugsystem
2 config GENERIC_HARDIRQS
14 mainmenu "Linux/Usermode Kernel Configuration"
25 config GENERIC_CALIBRATE_DELAY
29 # Used in kernel/irq/manage.c and include/linux/irq.h
30 config IRQ_RELEASE_METHOD
34 menu "UML-specific options"
37 bool "Tracing thread support"
40 This option controls whether tracing thread support is compiled
41 into UML. This option is largely obsolete, given that skas0 provides
42 skas security and performance without needing to patch the host.
43 It is safe to say 'N' here.
46 bool "Force a static link"
50 If CONFIG_MODE_TT is disabled, then this option gives you the ability
51 to force a static link of UML. Normally, if only skas mode is built
52 in to UML, it will be linked as a shared binary. This is inconvenient
53 for use in a chroot jail. So, if you intend to run UML inside a
54 chroot, and you disable CONFIG_MODE_TT, you probably want to say Y
58 bool "2G/2G host address space split"
62 This is needed when the host on which you run has a 2G/2G memory
63 split, instead of the customary 3G/1G.
65 Note that to enable such a host
66 configuration, which makes sense only in some cases, you need special
69 So, if you do not know what to do here, say 'N'.
71 config KERNEL_HALF_GIGS
72 int "Kernel address space size (in .5G units)"
76 This determines the amount of address space that UML will allocate for
77 its own, measured in half Gigabyte units. The default is 1.
78 Change this only if you need to boot UML with an unusually large amount
82 bool "Separate Kernel Address Space support" if MODE_TT
85 This option controls whether skas (separate kernel address space)
86 support is compiled in. If you have applied the skas patch to the
87 host, then you certainly want to say Y here (and consider saying N
88 to CONFIG_MODE_TT). Otherwise, it is safe to say Y. Disabling this
89 option will shrink the UML binary slightly.
91 source "arch/um/Kconfig.arch"
94 config LD_SCRIPT_STATIC
97 depends on MODE_TT || STATIC_LINK
102 depends on !LD_SCRIPT_STATIC
105 bool "Networking support"
107 Unless you really know what you are doing, you should say Y here.
108 The reason is that some programs need kernel networking support even
109 when running on a stand-alone machine that isn't connected to any
110 other computer. If you are upgrading from an older kernel, you
111 should consider updating your networking tools too because changes
112 in the kernel and the tools often go hand in hand. The tools are
113 contained in the package net-tools, the location and version number
114 of which are given in <file:Documentation/Changes>.
116 For a general introduction to Linux networking, it is highly
117 recommended to read the NET-HOWTO, available from
118 <http://www.tldp.org/docs.html#howto>.
121 source "fs/Kconfig.binfmt"
124 tristate "Host filesystem"
126 While the User-Mode Linux port uses its own root file system for
127 booting and normal file access, this module lets the UML user
128 access files stored on the host. It does not require any
129 network connection between the Host and UML. An example use of
132 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
134 where /tmp/fromhost is an empty directory inside UML and
135 /tmp/umlshare is a directory on the host with files the UML user
138 For more information, see
139 <http://user-mode-linux.sourceforge.net/hostfs.html>.
141 If you'd like to be able to work with files stored on the host,
142 say Y or M here; otherwise say N.
145 tristate "HoneyPot ProcFS (EXPERIMENTAL)"
146 depends on EXPERIMENTAL
148 hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
149 entries to be overridden, removed, or fabricated from the host.
150 Its purpose is to allow a UML to appear to be a physical machine
151 by removing or changing anything in /proc which gives away the
154 See <http://user-mode-linux.sf.net/hppfs.html> for more information.
156 You only need this if you are setting up a UML honeypot. Otherwise,
157 it is safe to say 'N' here.
160 bool "Management console"
163 The user mode linux management console is a low-level interface to
164 the kernel, somewhat like the i386 SysRq interface. Since there is
165 a full-blown operating system running under every user mode linux
166 instance, there is much greater flexibility possible than with the
169 If you answer 'Y' to this option, to use this feature, you need the
170 mconsole client (called uml_mconsole) which is present in CVS in
171 2.4.5-9um and later (path /tools/mconsole), and is also in the
172 distribution RPM package in 2.4.6 and later.
174 It is safe to say 'Y' here.
177 bool "Magic SysRq key"
180 If you say Y here, you will have some control over the system even
181 if the system crashes for example during kernel debugging (e.g., you
182 will be able to flush the buffer cache to disk, reboot the system
183 immediately or dump some status information). A key for each of the
184 possible requests is provided.
186 This is the feature normally accomplished by pressing a key
187 while holding SysRq (Alt+PrintScreen).
189 On UML, this is accomplished by sending a "sysrq" command with
190 mconsole, followed by the letter for the requested command.
192 The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
193 unless you really know what this hack does.
196 bool "Symmetric multi-processing support (EXPERIMENTAL)"
198 #SMP_BROKEN is for x86_64.
199 depends on MODE_TT && EXPERIMENTAL && (!SMP_BROKEN || (BROKEN && SMP_BROKEN))
201 This option enables UML SMP support.
202 It is NOT related to having a real SMP box. Not directly, at least.
204 UML implements virtual SMP by allowing as many processes to run
205 simultaneously on the host as there are virtual processors configured.
207 Obviously, if the host is a uniprocessor, those processes will
208 timeshare, but, inside UML, will appear to be running simultaneously.
209 If the host is a multiprocessor, then UML processes may run
210 simultaneously, depending on the host scheduler.
212 This, however, is supported only in TT mode. So, if you use the SKAS
213 patch on your host, switching to TT mode and enabling SMP usually gives
214 you worse performances.
215 Also, since the support for SMP has been under-developed, there could
216 be some bugs being exposed by enabling SMP.
218 If you don't know what to do, say N.
221 int "Maximum number of CPUs (2-32)"
230 This is set to the number of layers of UMLs that this UML will be run
231 in. Normally, this is zero, meaning that it will run directly on the
232 host. Setting it to one will build a UML that can run inside a UML
233 that is running on the host. Generally, if you intend this UML to run
234 inside another UML, set CONFIG_NEST_LEVEL to one more than the host
237 Note that if the hosting UML has its CONFIG_KERNEL_HALF_GIGS set to
238 greater than one, then the guest UML should have its CONFIG_NEST_LEVEL
239 set to the host's CONFIG_NEST_LEVEL + CONFIG_KERNEL_HALF_GIGS.
240 Only change this if you are running nested UMLs.
243 bool "Highmem support (EXPERIMENTAL)"
244 depends on !64BIT && EXPERIMENTAL
247 This was used to allow UML to run with big amounts of memory.
248 Currently it is unstable, so if unsure say N.
250 To use big amounts of memory, it is recommended to disable TT mode (i.e.
251 CONFIG_MODE_TT) and enable static linking (i.e. CONFIG_STATIC_LINK) -
252 this should allow the guest to use up to 2.75G of memory.
254 config KERNEL_STACK_ORDER
255 int "Kernel stack size order"
258 This option determines the size of UML kernel stacks. They will
259 be 1 << order pages. The default is OK unless you're running Valgrind
260 on UML, in which case, set this to 3.
262 config UML_REAL_TIME_CLOCK
263 bool "Real-time Clock"
266 This option makes UML time deltas match wall clock deltas. This should
267 normally be enabled. The exception would be if you are debugging with
268 UML and spend long times with UML stopped at a breakpoint. In this
269 case, when UML is restarted, it will call the timer enough times to make
270 up for the time spent at the breakpoint. This could result in a
271 noticable lag. If this is a problem, then disable this option.
275 source "init/Kconfig"
277 source "drivers/block/Kconfig"
279 source "arch/um/Kconfig.char"
281 source "drivers/base/Kconfig"
285 source "arch/um/Kconfig.net"
287 source "drivers/net/Kconfig"
289 source "drivers/connector/Kconfig"
293 source "security/Kconfig"
295 source "crypto/Kconfig"
303 tristate "SCSI support"
305 # This gives us free_dma, which scsi.c wants.
306 config GENERIC_ISA_DMA
311 source "arch/um/Kconfig.scsi"
315 source "drivers/md/Kconfig"
318 source "drivers/mtd/Kconfig"
321 #This is just to shut up some Kconfig warnings, so no prompt.
326 source "arch/um/Kconfig.debug"