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 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 "Separate Kernel Address Space support"
65 This option controls whether skas (separate kernel address space)
66 support is compiled in. If you have applied the skas patch to the
67 host, then you certainly want to say Y here (and consider saying N
68 to CONFIG_MODE_TT). Otherwise, it is safe to say Y. Disabling this
69 option will shrink the UML binary slightly.
71 source "arch/um/Kconfig_arch"
73 config LD_SCRIPT_STATIC
76 depends on MODE_TT || STATIC_LINK
81 depends on !LD_SCRIPT_STATIC
84 bool "Networking support"
86 Unless you really know what you are doing, you should say Y here.
87 The reason is that some programs need kernel networking support even
88 when running on a stand-alone machine that isn't connected to any
89 other computer. If you are upgrading from an older kernel, you
90 should consider updating your networking tools too because changes
91 in the kernel and the tools often go hand in hand. The tools are
92 contained in the package net-tools, the location and version number
93 of which are given in <file:Documentation/Changes>.
95 For a general introduction to Linux networking, it is highly
96 recommended to read the NET-HOWTO, available from
97 <http://www.tldp.org/docs.html#howto>.
100 source "fs/Kconfig.binfmt"
103 tristate "Host filesystem"
105 While the User-Mode Linux port uses its own root file system for
106 booting and normal file access, this module lets the UML user
107 access files stored on the host. It does not require any
108 network connection between the Host and UML. An example use of
111 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
113 where /tmp/fromhost is an empty directory inside UML and
114 /tmp/umlshare is a directory on the host with files the UML user
117 For more information, see
118 <http://user-mode-linux.sourceforge.net/hostfs.html>.
120 If you'd like to be able to work with files stored on the host,
121 say Y or M here; otherwise say N.
124 tristate "HoneyPot ProcFS (EXPERIMENTAL)"
127 hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
128 entries to be overridden, removed, or fabricated from the host.
129 Its purpose is to allow a UML to appear to be a physical machine
130 by removing or changing anything in /proc which gives away the
133 See <http://user-mode-linux.sf.net/hppfs.html> for more information.
135 You only need this if you are setting up a UML honeypot. Otherwise,
136 it is safe to say 'N' here.
138 If you are actively using it, please ask for it to be fixed. In this
139 moment, it does not work on 2.6 (it works somehow on 2.4).
142 bool "Management console"
145 The user mode linux management console is a low-level interface to
146 the kernel, somewhat like the i386 SysRq interface. Since there is
147 a full-blown operating system running under every user mode linux
148 instance, there is much greater flexibility possible than with the
151 If you answer 'Y' to this option, to use this feature, you need the
152 mconsole client (called uml_mconsole) which is present in CVS in
153 2.4.5-9um and later (path /tools/mconsole), and is also in the
154 distribution RPM package in 2.4.6 and later.
156 It is safe to say 'Y' here.
159 bool "Magic SysRq key"
162 If you say Y here, you will have some control over the system even
163 if the system crashes for example during kernel debugging (e.g., you
164 will be able to flush the buffer cache to disk, reboot the system
165 immediately or dump some status information). A key for each of the
166 possible requests is provided.
168 This is the feature normally accomplished by pressing a key
169 while holding SysRq (Alt+PrintScreen).
171 On UML, this is accomplished by sending a "sysrq" command with
172 mconsole, followed by the letter for the requested command.
174 The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
175 unless you really know what this hack does.
178 bool "2G/2G host address space split"
181 This is needed when the host on which you run has a 2G/2G memory
182 split, instead of the customary 3G/1G.
184 Note that to enable such a host
185 configuration, which makes sense only in some cases, you need special
188 So, if you do not know what to do here, say 'N'.
191 bool "Symmetric multi-processing support (EXPERIMENTAL)"
193 depends on MODE_TT && EXPERIMENTAL
195 This option enables UML SMP support.
196 It is NOT related to having a real SMP box. Not directly, at least.
198 UML implements virtual SMP by allowing as many processes to run
199 simultaneously on the host as there are virtual processors configured.
201 Obviously, if the host is a uniprocessor, those processes will
202 timeshare, but, inside UML, will appear to be running simultaneously.
203 If the host is a multiprocessor, then UML processes may run
204 simultaneously, depending on the host scheduler.
206 This, however, is supported only in TT mode. So, if you use the SKAS
207 patch on your host, switching to TT mode and enabling SMP usually gives
208 you worse performances.
209 Also, since the support for SMP has been under-developed, there could
210 be some bugs being exposed by enabling SMP.
212 If you don't know what to do, say N.
215 int "Maximum number of CPUs (2-32)"
224 This is set to the number of layers of UMLs that this UML will be run
225 in. Normally, this is zero, meaning that it will run directly on the
226 host. Setting it to one will build a UML that can run inside a UML
227 that is running on the host. Generally, if you intend this UML to run
228 inside another UML, set CONFIG_NEST_LEVEL to one more than the host
231 Note that if the hosting UML has its CONFIG_KERNEL_HALF_GIGS set to
232 greater than one, then the guest UML should have its CONFIG_NEST_LEVEL
233 set to the host's CONFIG_NEST_LEVEL + CONFIG_KERNEL_HALF_GIGS.
234 Only change this if you are running nested UMLs.
236 config KERNEL_HALF_GIGS
237 int "Kernel address space size (in .5G units)"
240 This determines the amount of address space that UML will allocate for
241 its own, measured in half Gigabyte units. The default is 1.
242 Change this only if you need to boot UML with an unusually large amount
246 bool "Highmem support"
248 config KERNEL_STACK_ORDER
249 int "Kernel stack size order"
252 This option determines the size of UML kernel stacks. They will
253 be 1 << order pages. The default is OK unless you're running Valgrind
254 on UML, in which case, set this to 3.
256 config UML_REAL_TIME_CLOCK
257 bool "Real-time Clock"
260 This option makes UML time deltas match wall clock deltas. This should
261 normally be enabled. The exception would be if you are debugging with
262 UML and spend long times with UML stopped at a breakpoint. In this
263 case, when UML is restarted, it will call the timer enough times to make
264 up for the time spent at the breakpoint. This could result in a
265 noticable lag. If this is a problem, then disable this option.
269 source "init/Kconfig"
271 source "drivers/base/Kconfig"
273 source "arch/um/Kconfig_char"
275 source "drivers/block/Kconfig"
281 source "arch/um/Kconfig_net"
287 source "security/Kconfig"
289 source "crypto/Kconfig"
297 tristate "SCSI support"
299 # This gives us free_dma, which scsi.c wants.
300 config GENERIC_ISA_DMA
305 source "arch/um/Kconfig_scsi"
309 source "drivers/md/Kconfig"
312 source "drivers/mtd/Kconfig"
315 #This is just to shut up some Kconfig warnings, so no prompt.
320 source "arch/um/Kconfig.debug"