1 # UML uses the generic IRQ sugsystem
2 config GENERIC_HARDIRQS
14 mainmenu "Linux/Usermode Kernel Configuration"
29 config GENERIC_CALIBRATE_DELAY
33 # Used in kernel/irq/manage.c and include/linux/irq.h
34 config IRQ_RELEASE_METHOD
38 menu "UML-specific options"
41 bool "Tracing thread support"
44 This option controls whether tracing thread support is compiled
45 into UML. Normally, this should be set to Y. If you intend to
46 use only skas mode (and the host has the skas patch applied to it),
47 then it is OK to say N here.
50 bool "Force a static link"
54 If CONFIG_MODE_TT is disabled, then this option gives you the ability
55 to force a static link of UML. Normally, if only skas mode is built
56 in to UML, it will be linked as a shared binary. This is inconvenient
57 for use in a chroot jail. So, if you intend to run UML inside a
58 chroot, and you disable CONFIG_MODE_TT, you probably want to say Y
62 bool "2G/2G host address space split"
66 This is needed when the host on which you run has a 2G/2G memory
67 split, instead of the customary 3G/1G.
69 Note that to enable such a host
70 configuration, which makes sense only in some cases, you need special
73 So, if you do not know what to do here, say 'N'.
75 config KERNEL_HALF_GIGS
76 int "Kernel address space size (in .5G units)"
80 This determines the amount of address space that UML will allocate for
81 its own, measured in half Gigabyte units. The default is 1.
82 Change this only if you need to boot UML with an unusually large amount
86 bool "Separate Kernel Address Space support" if MODE_TT
89 This option controls whether skas (separate kernel address space)
90 support is compiled in. If you have applied the skas patch to the
91 host, then you certainly want to say Y here (and consider saying N
92 to CONFIG_MODE_TT). Otherwise, it is safe to say Y. Disabling this
93 option will shrink the UML binary slightly.
95 source "arch/um/Kconfig.arch"
98 config LD_SCRIPT_STATIC
101 depends on MODE_TT || STATIC_LINK
106 depends on !LD_SCRIPT_STATIC
109 bool "Networking support"
111 Unless you really know what you are doing, you should say Y here.
112 The reason is that some programs need kernel networking support even
113 when running on a stand-alone machine that isn't connected to any
114 other computer. If you are upgrading from an older kernel, you
115 should consider updating your networking tools too because changes
116 in the kernel and the tools often go hand in hand. The tools are
117 contained in the package net-tools, the location and version number
118 of which are given in <file:Documentation/Changes>.
120 For a general introduction to Linux networking, it is highly
121 recommended to read the NET-HOWTO, available from
122 <http://www.tldp.org/docs.html#howto>.
125 source "fs/Kconfig.binfmt"
128 tristate "Host filesystem"
130 While the User-Mode Linux port uses its own root file system for
131 booting and normal file access, this module lets the UML user
132 access files stored on the host. It does not require any
133 network connection between the Host and UML. An example use of
136 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
138 where /tmp/fromhost is an empty directory inside UML and
139 /tmp/umlshare is a directory on the host with files the UML user
142 For more information, see
143 <http://user-mode-linux.sourceforge.net/hostfs.html>.
145 If you'd like to be able to work with files stored on the host,
146 say Y or M here; otherwise say N.
149 tristate "HoneyPot ProcFS (EXPERIMENTAL)"
151 hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
152 entries to be overridden, removed, or fabricated from the host.
153 Its purpose is to allow a UML to appear to be a physical machine
154 by removing or changing anything in /proc which gives away the
157 See <http://user-mode-linux.sf.net/hppfs.html> for more information.
159 You only need this if you are setting up a UML honeypot. Otherwise,
160 it is safe to say 'N' here.
162 If you are actively using it, please report any problems, since it's
163 getting fixed. In this moment, it is experimental on 2.6 (it works on
167 bool "Management console"
170 The user mode linux management console is a low-level interface to
171 the kernel, somewhat like the i386 SysRq interface. Since there is
172 a full-blown operating system running under every user mode linux
173 instance, there is much greater flexibility possible than with the
176 If you answer 'Y' to this option, to use this feature, you need the
177 mconsole client (called uml_mconsole) which is present in CVS in
178 2.4.5-9um and later (path /tools/mconsole), and is also in the
179 distribution RPM package in 2.4.6 and later.
181 It is safe to say 'Y' here.
184 bool "Magic SysRq key"
187 If you say Y here, you will have some control over the system even
188 if the system crashes for example during kernel debugging (e.g., you
189 will be able to flush the buffer cache to disk, reboot the system
190 immediately or dump some status information). A key for each of the
191 possible requests is provided.
193 This is the feature normally accomplished by pressing a key
194 while holding SysRq (Alt+PrintScreen).
196 On UML, this is accomplished by sending a "sysrq" command with
197 mconsole, followed by the letter for the requested command.
199 The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
200 unless you really know what this hack does.
203 bool "Symmetric multi-processing support (EXPERIMENTAL)"
205 #SMP_BROKEN is for x86_64.
206 depends on MODE_TT && EXPERIMENTAL && (!SMP_BROKEN || (BROKEN && SMP_BROKEN))
208 This option enables UML SMP support.
209 It is NOT related to having a real SMP box. Not directly, at least.
211 UML implements virtual SMP by allowing as many processes to run
212 simultaneously on the host as there are virtual processors configured.
214 Obviously, if the host is a uniprocessor, those processes will
215 timeshare, but, inside UML, will appear to be running simultaneously.
216 If the host is a multiprocessor, then UML processes may run
217 simultaneously, depending on the host scheduler.
219 This, however, is supported only in TT mode. So, if you use the SKAS
220 patch on your host, switching to TT mode and enabling SMP usually gives
221 you worse performances.
222 Also, since the support for SMP has been under-developed, there could
223 be some bugs being exposed by enabling SMP.
225 If you don't know what to do, say N.
228 int "Maximum number of CPUs (2-32)"
237 This is set to the number of layers of UMLs that this UML will be run
238 in. Normally, this is zero, meaning that it will run directly on the
239 host. Setting it to one will build a UML that can run inside a UML
240 that is running on the host. Generally, if you intend this UML to run
241 inside another UML, set CONFIG_NEST_LEVEL to one more than the host
244 Note that if the hosting UML has its CONFIG_KERNEL_HALF_GIGS set to
245 greater than one, then the guest UML should have its CONFIG_NEST_LEVEL
246 set to the host's CONFIG_NEST_LEVEL + CONFIG_KERNEL_HALF_GIGS.
247 Only change this if you are running nested UMLs.
250 bool "Highmem support"
253 config KERNEL_STACK_ORDER
254 int "Kernel stack size order"
257 This option determines the size of UML kernel stacks. They will
258 be 1 << order pages. The default is OK unless you're running Valgrind
259 on UML, in which case, set this to 3.
261 config UML_REAL_TIME_CLOCK
262 bool "Real-time Clock"
265 This option makes UML time deltas match wall clock deltas. This should
266 normally be enabled. The exception would be if you are debugging with
267 UML and spend long times with UML stopped at a breakpoint. In this
268 case, when UML is restarted, it will call the timer enough times to make
269 up for the time spent at the breakpoint. This could result in a
270 noticable lag. If this is a problem, then disable this option.
274 source "init/Kconfig"
278 source "drivers/base/Kconfig"
280 source "arch/um/Kconfig.char"
282 source "drivers/block/Kconfig"
288 source "arch/um/Kconfig.net"
290 source "drivers/net/Kconfig"
292 source "drivers/connector/Kconfig"
296 source "security/Kconfig"
298 source "crypto/Kconfig"
306 tristate "SCSI support"
308 # This gives us free_dma, which scsi.c wants.
309 config GENERIC_ISA_DMA
314 source "arch/um/Kconfig.scsi"
318 source "drivers/md/Kconfig"
321 source "drivers/mtd/Kconfig"
324 #This is just to shut up some Kconfig warnings, so no prompt.
329 source "arch/um/Kconfig.debug"