4 default "arch/$ARCH/defconfig"
6 # UML uses the generic IRQ sugsystem
7 config GENERIC_HARDIRQS
19 mainmenu "Linux/Usermode Kernel Configuration"
34 config TRACE_IRQFLAGS_SUPPORT
38 config LOCKDEP_SUPPORT
42 config STACKTRACE_SUPPORT
46 config GENERIC_CALIBRATE_DELAY
50 # Used in kernel/irq/manage.c and include/linux/irq.h
51 config IRQ_RELEASE_METHOD
55 menu "UML-specific options"
58 bool "Tracing thread support (DEPRECATED)"
62 This option controls whether tracing thread support is compiled
63 into UML. This option is largely obsolete, given that skas0 provides
64 skas security and performance without needing to patch the host.
65 It is safe to say 'N' here; saying 'Y' may cause additional problems
66 with the resulting binary even if you run UML in SKAS mode, and running
67 in TT mode is strongly *NOT RECOMMENDED*.
70 bool "Force a static link"
74 If CONFIG_MODE_TT is disabled, then this option gives you the ability
75 to force a static link of UML. Normally, if only skas mode is built
76 in to UML, it will be linked as a shared binary. This is inconvenient
77 for use in a chroot jail. So, if you intend to run UML inside a
78 chroot, and you disable CONFIG_MODE_TT, you probably want to say Y
80 Additionally, this option enables using higher memory spaces (up to
81 2.75G) for UML - disabling CONFIG_MODE_TT and enabling this option leads
82 to best results for this.
84 config KERNEL_HALF_GIGS
85 int "Kernel address space size (in .5G units)"
89 This determines the amount of address space that UML will allocate for
90 its own, measured in half Gigabyte units. The default is 1.
91 Change this only if you need to boot UML with an unusually large amount
95 bool "Separate Kernel Address Space support" if MODE_TT
98 This option controls whether skas (separate kernel address space)
99 support is compiled in.
100 Unless you have specific needs to use TT mode (which applies almost only
101 to developers), you should say Y here.
102 SKAS mode will make use of the SKAS3 patch if it is applied on the host
103 (and your UML will run in SKAS3 mode), but if no SKAS patch is applied
104 on the host it will run in SKAS0 mode, which is anyway faster than TT
107 source "arch/um/Kconfig.arch"
110 config LD_SCRIPT_STATIC
113 depends on MODE_TT || STATIC_LINK
118 depends on !LD_SCRIPT_STATIC
121 bool "Networking support"
123 Unless you really know what you are doing, you should say Y here.
124 The reason is that some programs need kernel networking support even
125 when running on a stand-alone machine that isn't connected to any
126 other computer. If you are upgrading from an older kernel, you
127 should consider updating your networking tools too because changes
128 in the kernel and the tools often go hand in hand. The tools are
129 contained in the package net-tools, the location and version number
130 of which are given in <file:Documentation/Changes>.
132 For a general introduction to Linux networking, it is highly
133 recommended to read the NET-HOWTO, available from
134 <http://www.tldp.org/docs.html#howto>.
137 source "fs/Kconfig.binfmt"
140 tristate "Host filesystem"
142 While the User-Mode Linux port uses its own root file system for
143 booting and normal file access, this module lets the UML user
144 access files stored on the host. It does not require any
145 network connection between the Host and UML. An example use of
148 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
150 where /tmp/fromhost is an empty directory inside UML and
151 /tmp/umlshare is a directory on the host with files the UML user
154 For more information, see
155 <http://user-mode-linux.sourceforge.net/hostfs.html>.
157 If you'd like to be able to work with files stored on the host,
158 say Y or M here; otherwise say N.
161 tristate "HoneyPot ProcFS (EXPERIMENTAL)"
162 depends on EXPERIMENTAL
164 hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
165 entries to be overridden, removed, or fabricated from the host.
166 Its purpose is to allow a UML to appear to be a physical machine
167 by removing or changing anything in /proc which gives away the
170 See <http://user-mode-linux.sf.net/hppfs.html> for more information.
172 You only need this if you are setting up a UML honeypot. Otherwise,
173 it is safe to say 'N' here.
176 bool "Management console"
179 The user mode linux management console is a low-level interface to
180 the kernel, somewhat like the i386 SysRq interface. Since there is
181 a full-blown operating system running under every user mode linux
182 instance, there is much greater flexibility possible than with the
185 If you answer 'Y' to this option, to use this feature, you need the
186 mconsole client (called uml_mconsole) which is present in CVS in
187 2.4.5-9um and later (path /tools/mconsole), and is also in the
188 distribution RPM package in 2.4.6 and later.
190 It is safe to say 'Y' here.
193 bool "Magic SysRq key"
196 If you say Y here, you will have some control over the system even
197 if the system crashes for example during kernel debugging (e.g., you
198 will be able to flush the buffer cache to disk, reboot the system
199 immediately or dump some status information). A key for each of the
200 possible requests is provided.
202 This is the feature normally accomplished by pressing a key
203 while holding SysRq (Alt+PrintScreen).
205 On UML, this is accomplished by sending a "sysrq" command with
206 mconsole, followed by the letter for the requested command.
208 The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
209 unless you really know what this hack does.
212 bool "Symmetric multi-processing support (EXPERIMENTAL)"
214 #SMP_BROKEN is for x86_64.
215 depends on MODE_TT && EXPERIMENTAL && (!SMP_BROKEN || (BROKEN && SMP_BROKEN))
217 This option enables UML SMP support.
218 It is NOT related to having a real SMP box. Not directly, at least.
220 UML implements virtual SMP by allowing as many processes to run
221 simultaneously on the host as there are virtual processors configured.
223 Obviously, if the host is a uniprocessor, those processes will
224 timeshare, but, inside UML, will appear to be running simultaneously.
225 If the host is a multiprocessor, then UML processes may run
226 simultaneously, depending on the host scheduler.
228 This, however, is supported only in TT mode. So, if you use the SKAS
229 patch on your host, switching to TT mode and enabling SMP usually gives
230 you worse performances.
231 Also, since the support for SMP has been under-developed, there could
232 be some bugs being exposed by enabling SMP.
234 If you don't know what to do, say N.
237 int "Maximum number of CPUs (2-32)"
246 This is set to the number of layers of UMLs that this UML will be run
247 in. Normally, this is zero, meaning that it will run directly on the
248 host. Setting it to one will build a UML that can run inside a UML
249 that is running on the host. Generally, if you intend this UML to run
250 inside another UML, set CONFIG_NEST_LEVEL to one more than the host
253 Note that if the hosting UML has its CONFIG_KERNEL_HALF_GIGS set to
254 greater than one, then the guest UML should have its CONFIG_NEST_LEVEL
255 set to the host's CONFIG_NEST_LEVEL + CONFIG_KERNEL_HALF_GIGS.
256 Only change this if you are running nested UMLs.
259 bool "Highmem support (EXPERIMENTAL)"
260 depends on !64BIT && EXPERIMENTAL
263 This was used to allow UML to run with big amounts of memory.
264 Currently it is unstable, so if unsure say N.
266 To use big amounts of memory, it is recommended to disable TT mode (i.e.
267 CONFIG_MODE_TT) and enable static linking (i.e. CONFIG_STATIC_LINK) -
268 this should allow the guest to use up to 2.75G of memory.
270 config KERNEL_STACK_ORDER
271 int "Kernel stack size order"
274 This option determines the size of UML kernel stacks. They will
275 be 1 << order pages. The default is OK unless you're running Valgrind
276 on UML, in which case, set this to 3.
278 config UML_REAL_TIME_CLOCK
279 bool "Real-time Clock"
282 This option makes UML time deltas match wall clock deltas. This should
283 normally be enabled. The exception would be if you are debugging with
284 UML and spend long times with UML stopped at a breakpoint. In this
285 case, when UML is restarted, it will call the timer enough times to make
286 up for the time spent at the breakpoint. This could result in a
287 noticeable lag. If this is a problem, then disable this option.
291 source "init/Kconfig"
293 source "drivers/block/Kconfig"
295 source "arch/um/Kconfig.char"
297 source "drivers/base/Kconfig"
301 source "arch/um/Kconfig.net"
303 source "drivers/net/Kconfig"
305 source "drivers/connector/Kconfig"
309 source "security/Kconfig"
311 source "crypto/Kconfig"
319 tristate "SCSI support"
321 # This gives us free_dma, which scsi.c wants.
322 config GENERIC_ISA_DMA
327 source "arch/um/Kconfig.scsi"
331 source "drivers/md/Kconfig"
334 source "drivers/mtd/Kconfig"
337 #This is just to shut up some Kconfig warnings, so no prompt.
342 source "arch/um/Kconfig.debug"