1 # UML uses the generic IRQ sugsystem
2 config GENERIC_HARDIRQS
14 mainmenu "Linux/Usermode Kernel Configuration"
29 config TRACE_IRQFLAGS_SUPPORT
33 config LOCKDEP_SUPPORT
37 config STACKTRACE_SUPPORT
41 config GENERIC_CALIBRATE_DELAY
45 # Used in kernel/irq/manage.c and include/linux/irq.h
46 config IRQ_RELEASE_METHOD
50 menu "UML-specific options"
53 bool "Tracing thread support"
56 This option controls whether tracing thread support is compiled
57 into UML. This option is largely obsolete, given that skas0 provides
58 skas security and performance without needing to patch the host.
59 It is safe to say 'N' here.
62 bool "Force a static link"
66 If CONFIG_MODE_TT is disabled, then this option gives you the ability
67 to force a static link of UML. Normally, if only skas mode is built
68 in to UML, it will be linked as a shared binary. This is inconvenient
69 for use in a chroot jail. So, if you intend to run UML inside a
70 chroot, and you disable CONFIG_MODE_TT, you probably want to say Y
73 config KERNEL_HALF_GIGS
74 int "Kernel address space size (in .5G units)"
78 This determines the amount of address space that UML will allocate for
79 its own, measured in half Gigabyte units. The default is 1.
80 Change this only if you need to boot UML with an unusually large amount
84 bool "Separate Kernel Address Space support" if MODE_TT
87 This option controls whether skas (separate kernel address space)
88 support is compiled in. If you have applied the skas patch to the
89 host, then you certainly want to say Y here (and consider saying N
90 to CONFIG_MODE_TT). Otherwise, it is safe to say Y. Disabling this
91 option will shrink the UML binary slightly.
93 source "arch/um/Kconfig.arch"
96 config LD_SCRIPT_STATIC
99 depends on MODE_TT || STATIC_LINK
104 depends on !LD_SCRIPT_STATIC
107 bool "Networking support"
109 Unless you really know what you are doing, you should say Y here.
110 The reason is that some programs need kernel networking support even
111 when running on a stand-alone machine that isn't connected to any
112 other computer. If you are upgrading from an older kernel, you
113 should consider updating your networking tools too because changes
114 in the kernel and the tools often go hand in hand. The tools are
115 contained in the package net-tools, the location and version number
116 of which are given in <file:Documentation/Changes>.
118 For a general introduction to Linux networking, it is highly
119 recommended to read the NET-HOWTO, available from
120 <http://www.tldp.org/docs.html#howto>.
123 source "fs/Kconfig.binfmt"
126 tristate "Host filesystem"
128 While the User-Mode Linux port uses its own root file system for
129 booting and normal file access, this module lets the UML user
130 access files stored on the host. It does not require any
131 network connection between the Host and UML. An example use of
134 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
136 where /tmp/fromhost is an empty directory inside UML and
137 /tmp/umlshare is a directory on the host with files the UML user
140 For more information, see
141 <http://user-mode-linux.sourceforge.net/hostfs.html>.
143 If you'd like to be able to work with files stored on the host,
144 say Y or M here; otherwise say N.
147 tristate "HoneyPot ProcFS (EXPERIMENTAL)"
148 depends on EXPERIMENTAL
150 hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
151 entries to be overridden, removed, or fabricated from the host.
152 Its purpose is to allow a UML to appear to be a physical machine
153 by removing or changing anything in /proc which gives away the
156 See <http://user-mode-linux.sf.net/hppfs.html> for more information.
158 You only need this if you are setting up a UML honeypot. Otherwise,
159 it is safe to say 'N' here.
162 bool "Management console"
165 The user mode linux management console is a low-level interface to
166 the kernel, somewhat like the i386 SysRq interface. Since there is
167 a full-blown operating system running under every user mode linux
168 instance, there is much greater flexibility possible than with the
171 If you answer 'Y' to this option, to use this feature, you need the
172 mconsole client (called uml_mconsole) which is present in CVS in
173 2.4.5-9um and later (path /tools/mconsole), and is also in the
174 distribution RPM package in 2.4.6 and later.
176 It is safe to say 'Y' here.
179 bool "Magic SysRq key"
182 If you say Y here, you will have some control over the system even
183 if the system crashes for example during kernel debugging (e.g., you
184 will be able to flush the buffer cache to disk, reboot the system
185 immediately or dump some status information). A key for each of the
186 possible requests is provided.
188 This is the feature normally accomplished by pressing a key
189 while holding SysRq (Alt+PrintScreen).
191 On UML, this is accomplished by sending a "sysrq" command with
192 mconsole, followed by the letter for the requested command.
194 The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
195 unless you really know what this hack does.
198 bool "Symmetric multi-processing support (EXPERIMENTAL)"
200 #SMP_BROKEN is for x86_64.
201 depends on MODE_TT && EXPERIMENTAL && (!SMP_BROKEN || (BROKEN && SMP_BROKEN))
203 This option enables UML SMP support.
204 It is NOT related to having a real SMP box. Not directly, at least.
206 UML implements virtual SMP by allowing as many processes to run
207 simultaneously on the host as there are virtual processors configured.
209 Obviously, if the host is a uniprocessor, those processes will
210 timeshare, but, inside UML, will appear to be running simultaneously.
211 If the host is a multiprocessor, then UML processes may run
212 simultaneously, depending on the host scheduler.
214 This, however, is supported only in TT mode. So, if you use the SKAS
215 patch on your host, switching to TT mode and enabling SMP usually gives
216 you worse performances.
217 Also, since the support for SMP has been under-developed, there could
218 be some bugs being exposed by enabling SMP.
220 If you don't know what to do, say N.
223 int "Maximum number of CPUs (2-32)"
232 This is set to the number of layers of UMLs that this UML will be run
233 in. Normally, this is zero, meaning that it will run directly on the
234 host. Setting it to one will build a UML that can run inside a UML
235 that is running on the host. Generally, if you intend this UML to run
236 inside another UML, set CONFIG_NEST_LEVEL to one more than the host
239 Note that if the hosting UML has its CONFIG_KERNEL_HALF_GIGS set to
240 greater than one, then the guest UML should have its CONFIG_NEST_LEVEL
241 set to the host's CONFIG_NEST_LEVEL + CONFIG_KERNEL_HALF_GIGS.
242 Only change this if you are running nested UMLs.
245 bool "Highmem support (EXPERIMENTAL)"
246 depends on !64BIT && EXPERIMENTAL
249 This was used to allow UML to run with big amounts of memory.
250 Currently it is unstable, so if unsure say N.
252 To use big amounts of memory, it is recommended to disable TT mode (i.e.
253 CONFIG_MODE_TT) and enable static linking (i.e. CONFIG_STATIC_LINK) -
254 this should allow the guest to use up to 2.75G of memory.
256 config KERNEL_STACK_ORDER
257 int "Kernel stack size order"
260 This option determines the size of UML kernel stacks. They will
261 be 1 << order pages. The default is OK unless you're running Valgrind
262 on UML, in which case, set this to 3.
264 config UML_REAL_TIME_CLOCK
265 bool "Real-time Clock"
268 This option makes UML time deltas match wall clock deltas. This should
269 normally be enabled. The exception would be if you are debugging with
270 UML and spend long times with UML stopped at a breakpoint. In this
271 case, when UML is restarted, it will call the timer enough times to make
272 up for the time spent at the breakpoint. This could result in a
273 noticeable lag. If this is a problem, then disable this option.
277 source "init/Kconfig"
279 source "drivers/block/Kconfig"
281 source "arch/um/Kconfig.char"
283 source "drivers/base/Kconfig"
287 source "arch/um/Kconfig.net"
289 source "drivers/net/Kconfig"
291 source "drivers/connector/Kconfig"
295 source "security/Kconfig"
297 source "crypto/Kconfig"
305 tristate "SCSI support"
307 # This gives us free_dma, which scsi.c wants.
308 config GENERIC_ISA_DMA
313 source "arch/um/Kconfig.scsi"
317 source "drivers/md/Kconfig"
320 source "drivers/mtd/Kconfig"
323 #This is just to shut up some Kconfig warnings, so no prompt.
328 source "arch/um/Kconfig.debug"