5 # XXX: does UM have a mmu/swap?
10 mainmenu "Linux/Usermode Kernel Configuration"
25 config RWSEM_GENERIC_SPINLOCK
29 menu "UML-specific options"
32 bool "Tracing thread support"
35 This option controls whether tracing thread support is compiled
36 into UML. Normally, this should be set to Y. If you intend to
37 use only skas mode (and the host has the skas patch applied to it),
38 then it is OK to say N here.
41 bool "Force a static link"
45 If CONFIG_MODE_TT is disabled, then this option gives you the ability
46 to force a static link of UML. Normally, if only skas mode is built
47 in to UML, it will be linked as a shared binary. This is inconvenient
48 for use in a chroot jail. So, if you intend to run UML inside a
49 chroot, and you disable CONFIG_MODE_TT, you probably want to say Y
53 bool "Separate Kernel Address Space support"
56 This option controls whether skas (separate kernel address space)
57 support is compiled in. If you have applied the skas patch to the
58 host, then you certainly want to say Y here (and consider saying N
59 to CONFIG_MODE_TT). Otherwise, it is safe to say Y. Disabling this
60 option will shrink the UML binary slightly.
63 bool "Networking support"
65 Unless you really know what you are doing, you should say Y here.
66 The reason is that some programs need kernel networking support even
67 when running on a stand-alone machine that isn't connected to any
68 other computer. If you are upgrading from an older kernel, you
69 should consider updating your networking tools too because changes
70 in the kernel and the tools often go hand in hand. The tools are
71 contained in the package net-tools, the location and version number
72 of which are given in Documentation/Changes.
74 For a general introduction to Linux networking, it is highly
75 recommended to read the NET-HOWTO, available from
76 <http://www.tldp.org/docs.html#howto>.
79 source "fs/Kconfig.binfmt"
82 tristate "Host filesystem"
84 While the User-Mode Linux port uses its own root file system for
85 booting and normal file access, this module lets the UML user
86 access files stored on the host. It does not require any
87 network connection between the Host and UML. An example use of
90 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
92 where /tmp/fromhost is an empty directory inside UML and
93 /tmp/umlshare is a directory on the host with files the UML user
96 For more information, see
97 <http://user-mode-linux.sourceforge.net/hostfs.html>.
99 If you'd like to be able to work with files stored on the host,
100 say Y or M here; otherwise say N.
103 tristate "HoneyPot ProcFS"
105 hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
106 entries to be overridden, removed, or fabricated from the host.
107 Its purpose is to allow a UML to appear to be a physical machine
108 by removing or changing anything in /proc which gives away the
111 See http://user-mode-linux.sf.net/hppfs.html for more information.
113 You only need this if you are setting up a UML honeypot. Otherwise,
114 it is safe to say 'N' here.
117 bool "Management console"
119 The user mode linux management console is a low-level interface to
120 the kernel, somewhat like the i386 SysRq interface. Since there is
121 a full-blown operating system running under every user mode linux
122 instance, there is much greater flexibility possible than with the
125 If you answer 'Y' to this option, to use this feature, you need the
126 mconsole client (called uml_mconsole) which is present in CVS in
127 2.4.5-9um and later (path /tools/mconsole), and is also in the
128 distribution RPM package in 2.4.6 and later.
130 It is safe to say 'Y' here.
133 bool "Magic SysRq key"
136 If you say Y here, you will have some control over the system even
137 if the system crashes for example during kernel debugging (e.g., you
138 will be able to flush the buffer cache to disk, reboot the system
139 immediately or dump some status information). This is accomplished
140 by pressing various keys while holding SysRq (Alt+PrintScreen). It
141 also works on a serial console (on PC hardware at least), if you
142 send a BREAK and then within 5 seconds a command keypress. The
143 keys are documented in Documentation/sysrq.txt. Don't say Y
144 unless you really know what this hack does.
147 bool "2G/2G host address space split"
150 bool "Symmetric multi-processing support"
152 This option enables UML SMP support. UML implements virtual SMP by
153 allowing as many processes to run simultaneously on the host as
154 there are virtual processors configured. Obviously, if the host is
155 a uniprocessor, those processes will timeshare, but, inside UML,
156 will appear to be running simultaneously. If the host is a
157 multiprocessor, then UML processes may run simultaneously, depending
158 on the host scheduler.
159 CONFIG_SMP will be set to whatever this option is set to.
160 It is safe to leave this unchanged.
167 int "Maximum number of CPUs (2-32)"
176 This is set to the number of layers of UMLs that this UML will be run
177 in. Normally, this is zero, meaning that it will run directly on the
178 host. Setting it to one will build a UML that can run inside a UML
179 that is running on the host. Generally, if you intend this UML to run
180 inside another UML, set CONFIG_NEST_LEVEL to one more than the host
183 Note that if the hosting UML has its CONFIG_KERNEL_HALF_GIGS set to
184 greater than one, then the guest UML should have its CONFIG_NEST_LEVEL
185 set to the host's CONFIG_NEST_LEVEL + CONFIG_KERNEL_HALF_GIGS.
186 Only change this if you are running nested UMLs.
188 config KERNEL_HALF_GIGS
189 int "Kernel address space size (in .5G units)"
192 This determines the amount of address space that UML will allocate for
193 its own, measured in half Gigabyte units. The default is 1.
194 Change this only if you need to boot UML with an unusually large amount
198 bool "Highmem support"
201 bool "/proc/mm support"
203 config KERNEL_STACK_ORDER
204 int "Kernel stack size order"
207 This option determines the size of UML kernel stacks. They will
208 be 1 << order pages. The default is OK unless you're running Valgrind
209 on UML, in which case, set this to 3.
211 config UML_REAL_TIME_CLOCK
212 bool "Real-time Clock"
215 This option makes UML time deltas match wall clock deltas. This should
216 normally be enabled. The exception would be if you are debugging with
217 UML and spend long times with UML stopped at a breakpoint. In this
218 case, when UML is restarted, it will call the timer enough times to make
219 up for the time spent at the breakpoint. This could result in a
220 noticable lag. If this is a problem, then disable this option.
224 source "init/Kconfig"
226 source "drivers/base/Kconfig"
228 source "arch/um/Kconfig_char"
230 source "arch/um/Kconfig_block"
236 source "arch/um/Kconfig_net"
242 source "kernel/vserver/Kconfig"
244 source "security/Kconfig"
246 source "crypto/Kconfig"
253 tristate "SCSI support"
255 # This gives us free_dma, which scsi.c wants.
256 config GENERIC_ISA_DMA
261 source "arch/um/Kconfig_scsi"
265 source "drivers/md/Kconfig"
267 source "drivers/mtd/Kconfig"
270 menu "Kernel hacking"
273 bool "Debug memory allocations"
275 config DEBUG_SPINLOCK
276 bool "Debug spinlocks usage"
279 bool "Enable kernel debugging symbols"
281 When this is enabled, the User-Mode Linux binary will include
282 debugging symbols. This enlarges the binary by a few megabytes,
283 but aids in tracking down kernel problems in UML. It is required
284 if you intend to do any kernel development.
286 If you're truly short on disk space or don't expect to report any
287 bugs back to the UML developers, say N, otherwise say Y.
291 default y if DEBUG_INFO
294 bool "Enable ptrace proxy"
295 depends on XTERM_CHAN && DEBUG_INFO
297 This option enables a debugging interface which allows gdb to debug
298 the kernel without needing to actually attach to kernel threads.
299 If you want to do kernel debugging, say Y here; otherwise say N.
302 bool "Enable gprof support"
303 depends on DEBUG_INFO
305 This allows profiling of a User-Mode Linux kernel with the gprof
308 See <http://user-mode-linux.sourceforge.net/gprof.html> for more
311 If you're involved in UML kernel development and want to use gprof,
312 say Y. If you're unsure, say N.
315 bool "Enable gcov support"
316 depends on DEBUG_INFO
318 This option allows developers to retrieve coverage data from a UML
321 See <http://user-mode-linux.sourceforge.net/gprof.html> for more
324 If you're involved in UML kernel development and want to use gcov,
325 say Y. If you're unsure, say N.