4 default "arch/$ARCH/defconfig"
6 # UML uses the generic IRQ sugsystem
7 config GENERIC_HARDIRQS
19 mainmenu "Linux/Usermode Kernel Configuration"
33 config GENERIC_CALIBRATE_DELAY
37 # Used in kernel/irq/manage.c and include/linux/irq.h
38 config IRQ_RELEASE_METHOD
42 menu "UML-specific options"
45 bool "Tracing thread support"
48 This option controls whether tracing thread support is compiled
49 into UML. This option is largely obsolete, given that skas0 provides
50 skas security and performance without needing to patch the host.
51 It is safe to say 'N' here.
54 bool "Force a static link"
58 If CONFIG_MODE_TT is disabled, then this option gives you the ability
59 to force a static link of UML. Normally, if only skas mode is built
60 in to UML, it will be linked as a shared binary. This is inconvenient
61 for use in a chroot jail. So, if you intend to run UML inside a
62 chroot, and you disable CONFIG_MODE_TT, you probably want to say Y
65 config KERNEL_HALF_GIGS
66 int "Kernel address space size (in .5G units)"
70 This determines the amount of address space that UML will allocate for
71 its own, measured in half Gigabyte units. The default is 1.
72 Change this only if you need to boot UML with an unusually large amount
76 bool "Separate Kernel Address Space support" if MODE_TT
79 This option controls whether skas (separate kernel address space)
80 support is compiled in. If you have applied the skas patch to the
81 host, then you certainly want to say Y here (and consider saying N
82 to CONFIG_MODE_TT). Otherwise, it is safe to say Y. Disabling this
83 option will shrink the UML binary slightly.
85 source "arch/um/Kconfig.arch"
88 config LD_SCRIPT_STATIC
91 depends on MODE_TT || STATIC_LINK
96 depends on !LD_SCRIPT_STATIC
99 bool "Networking support"
101 Unless you really know what you are doing, you should say Y here.
102 The reason is that some programs need kernel networking support even
103 when running on a stand-alone machine that isn't connected to any
104 other computer. If you are upgrading from an older kernel, you
105 should consider updating your networking tools too because changes
106 in the kernel and the tools often go hand in hand. The tools are
107 contained in the package net-tools, the location and version number
108 of which are given in <file:Documentation/Changes>.
110 For a general introduction to Linux networking, it is highly
111 recommended to read the NET-HOWTO, available from
112 <http://www.tldp.org/docs.html#howto>.
115 source "fs/Kconfig.binfmt"
118 tristate "Host filesystem"
120 While the User-Mode Linux port uses its own root file system for
121 booting and normal file access, this module lets the UML user
122 access files stored on the host. It does not require any
123 network connection between the Host and UML. An example use of
126 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
128 where /tmp/fromhost is an empty directory inside UML and
129 /tmp/umlshare is a directory on the host with files the UML user
132 For more information, see
133 <http://user-mode-linux.sourceforge.net/hostfs.html>.
135 If you'd like to be able to work with files stored on the host,
136 say Y or M here; otherwise say N.
139 tristate "HoneyPot ProcFS (EXPERIMENTAL)"
140 depends on EXPERIMENTAL
142 hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
143 entries to be overridden, removed, or fabricated from the host.
144 Its purpose is to allow a UML to appear to be a physical machine
145 by removing or changing anything in /proc which gives away the
148 See <http://user-mode-linux.sf.net/hppfs.html> for more information.
150 You only need this if you are setting up a UML honeypot. Otherwise,
151 it is safe to say 'N' here.
154 bool "Management console"
157 The user mode linux management console is a low-level interface to
158 the kernel, somewhat like the i386 SysRq interface. Since there is
159 a full-blown operating system running under every user mode linux
160 instance, there is much greater flexibility possible than with the
163 If you answer 'Y' to this option, to use this feature, you need the
164 mconsole client (called uml_mconsole) which is present in CVS in
165 2.4.5-9um and later (path /tools/mconsole), and is also in the
166 distribution RPM package in 2.4.6 and later.
168 It is safe to say 'Y' here.
171 bool "Magic SysRq key"
174 If you say Y here, you will have some control over the system even
175 if the system crashes for example during kernel debugging (e.g., you
176 will be able to flush the buffer cache to disk, reboot the system
177 immediately or dump some status information). A key for each of the
178 possible requests is provided.
180 This is the feature normally accomplished by pressing a key
181 while holding SysRq (Alt+PrintScreen).
183 On UML, this is accomplished by sending a "sysrq" command with
184 mconsole, followed by the letter for the requested command.
186 The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
187 unless you really know what this hack does.
190 bool "Symmetric multi-processing support (EXPERIMENTAL)"
192 #SMP_BROKEN is for x86_64.
193 depends on MODE_TT && EXPERIMENTAL && (!SMP_BROKEN || (BROKEN && SMP_BROKEN))
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.
237 bool "Highmem support (EXPERIMENTAL)"
238 depends on !64BIT && EXPERIMENTAL
241 This was used to allow UML to run with big amounts of memory.
242 Currently it is unstable, so if unsure say N.
244 To use big amounts of memory, it is recommended to disable TT mode (i.e.
245 CONFIG_MODE_TT) and enable static linking (i.e. CONFIG_STATIC_LINK) -
246 this should allow the guest to use up to 2.75G of memory.
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/block/Kconfig"
273 source "arch/um/Kconfig.char"
275 source "drivers/base/Kconfig"
279 source "arch/um/Kconfig.net"
281 source "drivers/net/Kconfig"
283 source "drivers/connector/Kconfig"
287 source "kernel/vserver/Kconfig"
289 source "security/Kconfig"
291 source "crypto/Kconfig"
299 tristate "SCSI support"
301 # This gives us free_dma, which scsi.c wants.
302 config GENERIC_ISA_DMA
307 source "arch/um/Kconfig.scsi"
311 source "drivers/md/Kconfig"
314 source "drivers/mtd/Kconfig"
317 #This is just to shut up some Kconfig warnings, so no prompt.
322 source "arch/um/Kconfig.debug"