4 default "arch/$ARCH/defconfig"
6 # UML uses the generic IRQ sugsystem
7 config GENERIC_HARDIRQS
19 mainmenu "Linux/Usermode Kernel Configuration"
34 config TRACE_IRQFLAGS_SUPPORT
38 config LOCKDEP_SUPPORT
42 config STACKTRACE_SUPPORT
46 config GENERIC_CALIBRATE_DELAY
55 # Used in kernel/irq/manage.c and include/linux/irq.h
56 config IRQ_RELEASE_METHOD
60 menu "UML-specific options"
63 bool "Tracing thread support (DEPRECATED)"
67 This option controls whether tracing thread support is compiled
68 into UML. This option is largely obsolete, given that skas0 provides
69 skas security and performance without needing to patch the host.
70 It is safe to say 'N' here; saying 'Y' may cause additional problems
71 with the resulting binary even if you run UML in SKAS mode, and running
72 in TT mode is strongly *NOT RECOMMENDED*.
75 bool "Force a static link"
79 If CONFIG_MODE_TT is disabled, then this option gives you the ability
80 to force a static link of UML. Normally, if only skas mode is built
81 in to UML, it will be linked as a shared binary. This is inconvenient
82 for use in a chroot jail. So, if you intend to run UML inside a
83 chroot, and you disable CONFIG_MODE_TT, you probably want to say Y
85 Additionally, this option enables using higher memory spaces (up to
86 2.75G) for UML - disabling CONFIG_MODE_TT and enabling this option leads
87 to best results for this.
89 config KERNEL_HALF_GIGS
90 int "Kernel address space size (in .5G units)"
94 This determines the amount of address space that UML will allocate for
95 its own, measured in half Gigabyte units. The default is 1.
96 Change this only if you need to boot UML with an unusually large amount
100 bool "Separate Kernel Address Space support" if MODE_TT
103 This option controls whether skas (separate kernel address space)
104 support is compiled in.
105 Unless you have specific needs to use TT mode (which applies almost only
106 to developers), you should say Y here.
107 SKAS mode will make use of the SKAS3 patch if it is applied on the host
108 (and your UML will run in SKAS3 mode), but if no SKAS patch is applied
109 on the host it will run in SKAS0 mode, which is anyway faster than TT
112 source "arch/um/Kconfig.arch"
115 config LD_SCRIPT_STATIC
118 depends on MODE_TT || STATIC_LINK
123 depends on !LD_SCRIPT_STATIC
126 bool "Networking support"
128 Unless you really know what you are doing, you should say Y here.
129 The reason is that some programs need kernel networking support even
130 when running on a stand-alone machine that isn't connected to any
131 other computer. If you are upgrading from an older kernel, you
132 should consider updating your networking tools too because changes
133 in the kernel and the tools often go hand in hand. The tools are
134 contained in the package net-tools, the location and version number
135 of which are given in <file:Documentation/Changes>.
137 For a general introduction to Linux networking, it is highly
138 recommended to read the NET-HOWTO, available from
139 <http://www.tldp.org/docs.html#howto>.
142 source "fs/Kconfig.binfmt"
145 tristate "Host filesystem"
147 While the User-Mode Linux port uses its own root file system for
148 booting and normal file access, this module lets the UML user
149 access files stored on the host. It does not require any
150 network connection between the Host and UML. An example use of
153 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
155 where /tmp/fromhost is an empty directory inside UML and
156 /tmp/umlshare is a directory on the host with files the UML user
159 For more information, see
160 <http://user-mode-linux.sourceforge.net/hostfs.html>.
162 If you'd like to be able to work with files stored on the host,
163 say Y or M here; otherwise say N.
166 tristate "HoneyPot ProcFS (EXPERIMENTAL)"
167 depends on EXPERIMENTAL
169 hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
170 entries to be overridden, removed, or fabricated from the host.
171 Its purpose is to allow a UML to appear to be a physical machine
172 by removing or changing anything in /proc which gives away the
175 See <http://user-mode-linux.sf.net/hppfs.html> for more information.
177 You only need this if you are setting up a UML honeypot. Otherwise,
178 it is safe to say 'N' here.
181 bool "Management console"
184 The user mode linux management console is a low-level interface to
185 the kernel, somewhat like the i386 SysRq interface. Since there is
186 a full-blown operating system running under every user mode linux
187 instance, there is much greater flexibility possible than with the
190 If you answer 'Y' to this option, to use this feature, you need the
191 mconsole client (called uml_mconsole) which is present in CVS in
192 2.4.5-9um and later (path /tools/mconsole), and is also in the
193 distribution RPM package in 2.4.6 and later.
195 It is safe to say 'Y' here.
198 bool "Magic SysRq key"
201 If you say Y here, you will have some control over the system even
202 if the system crashes for example during kernel debugging (e.g., you
203 will be able to flush the buffer cache to disk, reboot the system
204 immediately or dump some status information). A key for each of the
205 possible requests is provided.
207 This is the feature normally accomplished by pressing a key
208 while holding SysRq (Alt+PrintScreen).
210 On UML, this is accomplished by sending a "sysrq" command with
211 mconsole, followed by the letter for the requested command.
213 The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
214 unless you really know what this hack does.
217 bool "Symmetric multi-processing support (EXPERIMENTAL)"
219 #SMP_BROKEN is for x86_64.
220 depends on MODE_TT && EXPERIMENTAL && (!SMP_BROKEN || (BROKEN && SMP_BROKEN))
222 This option enables UML SMP support.
223 It is NOT related to having a real SMP box. Not directly, at least.
225 UML implements virtual SMP by allowing as many processes to run
226 simultaneously on the host as there are virtual processors configured.
228 Obviously, if the host is a uniprocessor, those processes will
229 timeshare, but, inside UML, will appear to be running simultaneously.
230 If the host is a multiprocessor, then UML processes may run
231 simultaneously, depending on the host scheduler.
233 This, however, is supported only in TT mode. So, if you use the SKAS
234 patch on your host, switching to TT mode and enabling SMP usually gives
235 you worse performances.
236 Also, since the support for SMP has been under-developed, there could
237 be some bugs being exposed by enabling SMP.
239 If you don't know what to do, say N.
242 int "Maximum number of CPUs (2-32)"
251 This is set to the number of layers of UMLs that this UML will be run
252 in. Normally, this is zero, meaning that it will run directly on the
253 host. Setting it to one will build a UML that can run inside a UML
254 that is running on the host. Generally, if you intend this UML to run
255 inside another UML, set CONFIG_NEST_LEVEL to one more than the host
258 Note that if the hosting UML has its CONFIG_KERNEL_HALF_GIGS set to
259 greater than one, then the guest UML should have its CONFIG_NEST_LEVEL
260 set to the host's CONFIG_NEST_LEVEL + CONFIG_KERNEL_HALF_GIGS.
261 Only change this if you are running nested UMLs.
264 bool "Highmem support (EXPERIMENTAL)"
265 depends on !64BIT && EXPERIMENTAL
268 This was used to allow UML to run with big amounts of memory.
269 Currently it is unstable, so if unsure say N.
271 To use big amounts of memory, it is recommended to disable TT mode (i.e.
272 CONFIG_MODE_TT) and enable static linking (i.e. CONFIG_STATIC_LINK) -
273 this should allow the guest to use up to 2.75G of memory.
275 config KERNEL_STACK_ORDER
276 int "Kernel stack size order"
279 This option determines the size of UML kernel stacks. They will
280 be 1 << order pages. The default is OK unless you're running Valgrind
281 on UML, in which case, set this to 3.
283 config UML_REAL_TIME_CLOCK
284 bool "Real-time Clock"
287 This option makes UML time deltas match wall clock deltas. This should
288 normally be enabled. The exception would be if you are debugging with
289 UML and spend long times with UML stopped at a breakpoint. In this
290 case, when UML is restarted, it will call the timer enough times to make
291 up for the time spent at the breakpoint. This could result in a
292 noticeable lag. If this is a problem, then disable this option.
296 source "init/Kconfig"
298 source "drivers/block/Kconfig"
300 source "arch/um/Kconfig.char"
302 source "drivers/base/Kconfig"
306 source "arch/um/Kconfig.net"
308 source "drivers/net/Kconfig"
310 source "drivers/connector/Kconfig"
314 source "security/Kconfig"
316 source "crypto/Kconfig"
324 tristate "SCSI support"
326 # This gives us free_dma, which scsi.c wants.
327 config GENERIC_ISA_DMA
332 source "arch/um/Kconfig.scsi"
336 source "drivers/md/Kconfig"
339 source "drivers/mtd/Kconfig"
342 #This is just to shut up some Kconfig warnings, so no prompt.
347 source "arch/um/Kconfig.debug"