1 # UML uses the generic IRQ sugsystem
2 config GENERIC_HARDIRQS
14 mainmenu "Linux/Usermode Kernel Configuration"
28 config GENERIC_CALIBRATE_DELAY
32 # Used in kernel/irq/manage.c and include/linux/irq.h
33 config IRQ_RELEASE_METHOD
37 menu "UML-specific options"
40 bool "Tracing thread support"
43 This option controls whether tracing thread support is compiled
44 into UML. This option is largely obsolete, given that skas0 provides
45 skas security and performance without needing to patch the host.
46 It is safe to say 'N' here.
49 bool "Force a static link"
53 If CONFIG_MODE_TT is disabled, then this option gives you the ability
54 to force a static link of UML. Normally, if only skas mode is built
55 in to UML, it will be linked as a shared binary. This is inconvenient
56 for use in a chroot jail. So, if you intend to run UML inside a
57 chroot, and you disable CONFIG_MODE_TT, you probably want to say Y
61 bool "2G/2G host address space split"
65 This is needed when the host on which you run has a 2G/2G memory
66 split, instead of the customary 3G/1G.
68 Note that to enable such a host
69 configuration, which makes sense only in some cases, you need special
72 So, if you do not know what to do here, say 'N'.
74 config KERNEL_HALF_GIGS
75 int "Kernel address space size (in .5G units)"
79 This determines the amount of address space that UML will allocate for
80 its own, measured in half Gigabyte units. The default is 1.
81 Change this only if you need to boot UML with an unusually large amount
85 bool "Separate Kernel Address Space support" if MODE_TT
88 This option controls whether skas (separate kernel address space)
89 support is compiled in. If you have applied the skas patch to the
90 host, then you certainly want to say Y here (and consider saying N
91 to CONFIG_MODE_TT). Otherwise, it is safe to say Y. Disabling this
92 option will shrink the UML binary slightly.
94 source "arch/um/Kconfig.arch"
97 config LD_SCRIPT_STATIC
100 depends on MODE_TT || STATIC_LINK
105 depends on !LD_SCRIPT_STATIC
108 bool "Networking support"
110 Unless you really know what you are doing, you should say Y here.
111 The reason is that some programs need kernel networking support even
112 when running on a stand-alone machine that isn't connected to any
113 other computer. If you are upgrading from an older kernel, you
114 should consider updating your networking tools too because changes
115 in the kernel and the tools often go hand in hand. The tools are
116 contained in the package net-tools, the location and version number
117 of which are given in <file:Documentation/Changes>.
119 For a general introduction to Linux networking, it is highly
120 recommended to read the NET-HOWTO, available from
121 <http://www.tldp.org/docs.html#howto>.
124 source "fs/Kconfig.binfmt"
127 tristate "Host filesystem"
129 While the User-Mode Linux port uses its own root file system for
130 booting and normal file access, this module lets the UML user
131 access files stored on the host. It does not require any
132 network connection between the Host and UML. An example use of
135 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
137 where /tmp/fromhost is an empty directory inside UML and
138 /tmp/umlshare is a directory on the host with files the UML user
141 For more information, see
142 <http://user-mode-linux.sourceforge.net/hostfs.html>.
144 If you'd like to be able to work with files stored on the host,
145 say Y or M here; otherwise say N.
148 tristate "HoneyPot ProcFS (EXPERIMENTAL)"
149 depends on 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.
163 bool "Management console"
166 The user mode linux management console is a low-level interface to
167 the kernel, somewhat like the i386 SysRq interface. Since there is
168 a full-blown operating system running under every user mode linux
169 instance, there is much greater flexibility possible than with the
172 If you answer 'Y' to this option, to use this feature, you need the
173 mconsole client (called uml_mconsole) which is present in CVS in
174 2.4.5-9um and later (path /tools/mconsole), and is also in the
175 distribution RPM package in 2.4.6 and later.
177 It is safe to say 'Y' here.
180 bool "Magic SysRq key"
183 If you say Y here, you will have some control over the system even
184 if the system crashes for example during kernel debugging (e.g., you
185 will be able to flush the buffer cache to disk, reboot the system
186 immediately or dump some status information). A key for each of the
187 possible requests is provided.
189 This is the feature normally accomplished by pressing a key
190 while holding SysRq (Alt+PrintScreen).
192 On UML, this is accomplished by sending a "sysrq" command with
193 mconsole, followed by the letter for the requested command.
195 The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
196 unless you really know what this hack does.
199 bool "Symmetric multi-processing support (EXPERIMENTAL)"
201 #SMP_BROKEN is for x86_64.
202 depends on MODE_TT && EXPERIMENTAL && (!SMP_BROKEN || (BROKEN && SMP_BROKEN))
204 This option enables UML SMP support.
205 It is NOT related to having a real SMP box. Not directly, at least.
207 UML implements virtual SMP by allowing as many processes to run
208 simultaneously on the host as there are virtual processors configured.
210 Obviously, if the host is a uniprocessor, those processes will
211 timeshare, but, inside UML, will appear to be running simultaneously.
212 If the host is a multiprocessor, then UML processes may run
213 simultaneously, depending on the host scheduler.
215 This, however, is supported only in TT mode. So, if you use the SKAS
216 patch on your host, switching to TT mode and enabling SMP usually gives
217 you worse performances.
218 Also, since the support for SMP has been under-developed, there could
219 be some bugs being exposed by enabling SMP.
221 If you don't know what to do, say N.
224 int "Maximum number of CPUs (2-32)"
233 This is set to the number of layers of UMLs that this UML will be run
234 in. Normally, this is zero, meaning that it will run directly on the
235 host. Setting it to one will build a UML that can run inside a UML
236 that is running on the host. Generally, if you intend this UML to run
237 inside another UML, set CONFIG_NEST_LEVEL to one more than the host
240 Note that if the hosting UML has its CONFIG_KERNEL_HALF_GIGS set to
241 greater than one, then the guest UML should have its CONFIG_NEST_LEVEL
242 set to the host's CONFIG_NEST_LEVEL + CONFIG_KERNEL_HALF_GIGS.
243 Only change this if you are running nested UMLs.
246 bool "Highmem support (EXPERIMENTAL)"
247 depends on !64BIT && EXPERIMENTAL
250 This was used to allow UML to run with big amounts of memory.
251 Currently it is unstable, so if unsure say N.
253 To use big amounts of memory, it is recommended to disable TT mode (i.e.
254 CONFIG_MODE_TT) and enable static linking (i.e. CONFIG_STATIC_LINK) -
255 this should allow the guest to use up to 2.75G of memory.
257 config KERNEL_STACK_ORDER
258 int "Kernel stack size order"
261 This option determines the size of UML kernel stacks. They will
262 be 1 << order pages. The default is OK unless you're running Valgrind
263 on UML, in which case, set this to 3.
265 config UML_REAL_TIME_CLOCK
266 bool "Real-time Clock"
269 This option makes UML time deltas match wall clock deltas. This should
270 normally be enabled. The exception would be if you are debugging with
271 UML and spend long times with UML stopped at a breakpoint. In this
272 case, when UML is restarted, it will call the timer enough times to make
273 up for the time spent at the breakpoint. This could result in a
274 noticable lag. If this is a problem, then disable this option.
278 source "init/Kconfig"
280 source "drivers/block/Kconfig"
282 source "arch/um/Kconfig.char"
284 source "drivers/base/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"