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