1 # UML uses the generic IRQ sugsystem
2 config GENERIC_HARDIRQS
10 # XXX: does UM have a mmu/swap?
15 mainmenu "Linux/Usermode Kernel Configuration"
30 config RWSEM_GENERIC_SPINLOCK
34 config GENERIC_CALIBRATE_DELAY
38 # Used in kernel/irq/manage.c and include/linux/irq.h
39 config IRQ_RELEASE_METHOD
43 menu "UML-specific options"
46 bool "Tracing thread support"
49 This option controls whether tracing thread support is compiled
50 into UML. Normally, this should be set to Y. If you intend to
51 use only skas mode (and the host has the skas patch applied to it),
52 then it is OK to say N here.
55 bool "Force a static link"
59 If CONFIG_MODE_TT is disabled, then this option gives you the ability
60 to force a static link of UML. Normally, if only skas mode is built
61 in to UML, it will be linked as a shared binary. This is inconvenient
62 for use in a chroot jail. So, if you intend to run UML inside a
63 chroot, and you disable CONFIG_MODE_TT, you probably want to say Y
67 bool "Separate Kernel Address Space support"
70 This option controls whether skas (separate kernel address space)
71 support is compiled in. If you have applied the skas patch to the
72 host, then you certainly want to say Y here (and consider saying N
73 to CONFIG_MODE_TT). Otherwise, it is safe to say Y. Disabling this
74 option will shrink the UML binary slightly.
76 source "arch/um/Kconfig_arch"
78 config LD_SCRIPT_STATIC
81 depends on MODE_TT || STATIC_LINK
86 depends on !LD_SCRIPT_STATIC
89 bool "Networking support"
91 Unless you really know what you are doing, you should say Y here.
92 The reason is that some programs need kernel networking support even
93 when running on a stand-alone machine that isn't connected to any
94 other computer. If you are upgrading from an older kernel, you
95 should consider updating your networking tools too because changes
96 in the kernel and the tools often go hand in hand. The tools are
97 contained in the package net-tools, the location and version number
98 of which are given in <file:Documentation/Changes>.
100 For a general introduction to Linux networking, it is highly
101 recommended to read the NET-HOWTO, available from
102 <http://www.tldp.org/docs.html#howto>.
105 source "fs/Kconfig.binfmt"
108 tristate "Host filesystem"
110 While the User-Mode Linux port uses its own root file system for
111 booting and normal file access, this module lets the UML user
112 access files stored on the host. It does not require any
113 network connection between the Host and UML. An example use of
116 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
118 where /tmp/fromhost is an empty directory inside UML and
119 /tmp/umlshare is a directory on the host with files the UML user
122 For more information, see
123 <http://user-mode-linux.sourceforge.net/hostfs.html>.
125 If you'd like to be able to work with files stored on the host,
126 say Y or M here; otherwise say N.
129 tristate "HoneyPot ProcFS (EXPERIMENTAL)"
132 hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
133 entries to be overridden, removed, or fabricated from the host.
134 Its purpose is to allow a UML to appear to be a physical machine
135 by removing or changing anything in /proc which gives away the
138 See <http://user-mode-linux.sf.net/hppfs.html> for more information.
140 You only need this if you are setting up a UML honeypot. Otherwise,
141 it is safe to say 'N' here.
143 If you are actively using it, please ask for it to be fixed. In this
144 moment, it does not work on 2.6 (it works somehow on 2.4).
147 bool "Management console"
150 The user mode linux management console is a low-level interface to
151 the kernel, somewhat like the i386 SysRq interface. Since there is
152 a full-blown operating system running under every user mode linux
153 instance, there is much greater flexibility possible than with the
156 If you answer 'Y' to this option, to use this feature, you need the
157 mconsole client (called uml_mconsole) which is present in CVS in
158 2.4.5-9um and later (path /tools/mconsole), and is also in the
159 distribution RPM package in 2.4.6 and later.
161 It is safe to say 'Y' here.
164 bool "Magic SysRq key"
167 If you say Y here, you will have some control over the system even
168 if the system crashes for example during kernel debugging (e.g., you
169 will be able to flush the buffer cache to disk, reboot the system
170 immediately or dump some status information). A key for each of the
171 possible requests is provided.
173 This is the feature normally accomplished by pressing a key
174 while holding SysRq (Alt+PrintScreen).
176 On UML, this is accomplished by sending a "sysrq" command with
177 mconsole, followed by the letter for the requested command.
179 The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
180 unless you really know what this hack does.
183 bool "2G/2G host address space split"
186 This is needed when the host on which you run has a 2G/2G memory
187 split, instead of the customary 3G/1G.
189 Note that to enable such a host
190 configuration, which makes sense only in some cases, you need special
193 So, if you do not know what to do here, say 'N'.
196 bool "Symmetric multi-processing support (EXPERIMENTAL)"
198 depends on MODE_TT && EXPERIMENTAL
200 This option enables UML SMP support.
201 It is NOT related to having a real SMP box. Not directly, at least.
203 UML implements virtual SMP by allowing as many processes to run
204 simultaneously on the host as there are virtual processors configured.
206 Obviously, if the host is a uniprocessor, those processes will
207 timeshare, but, inside UML, will appear to be running simultaneously.
208 If the host is a multiprocessor, then UML processes may run
209 simultaneously, depending on the host scheduler.
211 This, however, is supported only in TT mode. So, if you use the SKAS
212 patch on your host, switching to TT mode and enabling SMP usually gives
213 you worse performances.
214 Also, since the support for SMP has been under-developed, there could
215 be some bugs being exposed by enabling SMP.
217 If you don't know what to do, say N.
220 int "Maximum number of CPUs (2-32)"
229 This is set to the number of layers of UMLs that this UML will be run
230 in. Normally, this is zero, meaning that it will run directly on the
231 host. Setting it to one will build a UML that can run inside a UML
232 that is running on the host. Generally, if you intend this UML to run
233 inside another UML, set CONFIG_NEST_LEVEL to one more than the host
236 Note that if the hosting UML has its CONFIG_KERNEL_HALF_GIGS set to
237 greater than one, then the guest UML should have its CONFIG_NEST_LEVEL
238 set to the host's CONFIG_NEST_LEVEL + CONFIG_KERNEL_HALF_GIGS.
239 Only change this if you are running nested UMLs.
241 config KERNEL_HALF_GIGS
242 int "Kernel address space size (in .5G units)"
245 This determines the amount of address space that UML will allocate for
246 its own, measured in half Gigabyte units. The default is 1.
247 Change this only if you need to boot UML with an unusually large amount
251 bool "Highmem support"
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/base/Kconfig"
279 source "arch/um/Kconfig_char"
281 source "drivers/block/Kconfig"
287 source "arch/um/Kconfig_net"
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"