xref: /openbmc/linux/arch/um/Kconfig (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1# UML uses the generic IRQ sugsystem
2config GENERIC_HARDIRQS
3	bool
4	default y
5
6config UML
7	bool
8	default y
9
10# XXX: does UM have a mmu/swap?
11config MMU
12	bool
13	default y
14
15mainmenu "Linux/Usermode Kernel Configuration"
16
17config ISA
18	bool
19
20config SBUS
21	bool
22
23config PCI
24	bool
25
26config UID16
27	bool
28	default y
29
30config GENERIC_CALIBRATE_DELAY
31	bool
32	default y
33
34# Used in kernel/irq/manage.c and include/linux/irq.h
35config IRQ_RELEASE_METHOD
36	bool
37	default y
38
39menu "Host processor type and features"
40
41source "arch/i386/Kconfig.cpu"
42
43endmenu
44
45menu "UML-specific options"
46
47config MODE_TT
48	bool "Tracing thread support"
49	default y
50	help
51	This option controls whether tracing thread support is compiled
52	into UML.  Normally, this should be set to Y.  If you intend to
53	use only skas mode (and the host has the skas patch applied to it),
54	then it is OK to say N here.
55
56config STATIC_LINK
57	bool "Force a static link"
58	default n
59	depends on !MODE_TT
60	help
61	If CONFIG_MODE_TT is disabled, then this option gives you the ability
62	to force a static link of UML.  Normally, if only skas mode is built
63	in to UML, it will be linked as a shared binary.  This is inconvenient
64	for use in a chroot jail.  So, if you intend to run UML inside a
65	chroot, and you disable CONFIG_MODE_TT, you probably want to say Y
66	here.
67
68config MODE_SKAS
69	bool "Separate Kernel Address Space support"
70	default y
71	help
72	This option controls whether skas (separate kernel address space)
73	support is compiled in.  If you have applied the skas patch to the
74	host, then you certainly want to say Y here (and consider saying N
75	to CONFIG_MODE_TT).  Otherwise, it is safe to say Y.  Disabling this
76	option will shrink the UML binary slightly.
77
78source "arch/um/Kconfig.arch"
79source "mm/Kconfig"
80
81config LD_SCRIPT_STATIC
82	bool
83	default y
84	depends on MODE_TT || STATIC_LINK
85
86config LD_SCRIPT_DYN
87	bool
88	default y
89	depends on !LD_SCRIPT_STATIC
90
91config NET
92	bool "Networking support"
93	help
94	Unless you really know what you are doing, you should say Y here.
95	The reason is that some programs need kernel networking support even
96	when running on a stand-alone machine that isn't connected to any
97	other computer. If you are upgrading from an older kernel, you
98	should consider updating your networking tools too because changes
99	in the kernel and the tools often go hand in hand. The tools are
100	contained in the package net-tools, the location and version number
101	of which are given in <file:Documentation/Changes>.
102
103	For a general introduction to Linux networking, it is highly
104	recommended to read the NET-HOWTO, available from
105	<http://www.tldp.org/docs.html#howto>.
106
107
108source "fs/Kconfig.binfmt"
109
110config HOSTFS
111	tristate "Host filesystem"
112	help
113        While the User-Mode Linux port uses its own root file system for
114        booting and normal file access, this module lets the UML user
115        access files stored on the host.  It does not require any
116        network connection between the Host and UML.  An example use of
117        this might be:
118
119        mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
120
121        where /tmp/fromhost is an empty directory inside UML and
122        /tmp/umlshare is a directory on the host with files the UML user
123        wishes to access.
124
125        For more information, see
126        <http://user-mode-linux.sourceforge.net/hostfs.html>.
127
128        If you'd like to be able to work with files stored on the host,
129        say Y or M here; otherwise say N.
130
131config HPPFS
132	tristate "HoneyPot ProcFS (EXPERIMENTAL)"
133	help
134	hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
135	entries to be overridden, removed, or fabricated from the host.
136	Its purpose is to allow a UML to appear to be a physical machine
137	by removing or changing anything in /proc which gives away the
138	identity of a UML.
139
140	See <http://user-mode-linux.sf.net/hppfs.html> for more information.
141
142	You only need this if you are setting up a UML honeypot.  Otherwise,
143	it is safe to say 'N' here.
144
145	If you are actively using it, please report any problems, since it's
146	getting fixed. In this moment, it is experimental on 2.6 (it works on
147	2.4).
148
149config MCONSOLE
150	bool "Management console"
151	default y
152	help
153        The user mode linux management console is a low-level interface to
154        the kernel, somewhat like the i386 SysRq interface.  Since there is
155        a full-blown operating system running under every user mode linux
156        instance, there is much greater flexibility possible than with the
157        SysRq mechanism.
158
159        If you answer 'Y' to this option, to use this feature, you need the
160        mconsole client (called uml_mconsole) which is present in CVS in
161        2.4.5-9um and later (path /tools/mconsole), and is also in the
162        distribution RPM package in 2.4.6 and later.
163
164        It is safe to say 'Y' here.
165
166config MAGIC_SYSRQ
167	bool "Magic SysRq key"
168	depends on MCONSOLE
169	---help---
170	If you say Y here, you will have some control over the system even
171	if the system crashes for example during kernel debugging (e.g., you
172	will be able to flush the buffer cache to disk, reboot the system
173	immediately or dump some status information). A key for each of the
174	possible requests is provided.
175
176	This is the feature normally accomplished by pressing a key
177	while holding SysRq (Alt+PrintScreen).
178
179	On UML, this is accomplished by sending a "sysrq" command with
180	mconsole, followed by the letter for the requested command.
181
182	The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
183	unless you really know what this hack does.
184
185config HOST_2G_2G
186	bool "2G/2G host address space split"
187	default n
188	help
189	This is needed when the host on which you run has a 2G/2G memory
190	split, instead of the customary 3G/1G.
191
192	Note that to enable such a host
193	configuration, which makes sense only in some cases, you need special
194	host patches.
195
196	So, if you do not know what to do here, say 'N'.
197
198config SMP
199	bool "Symmetric multi-processing support (EXPERIMENTAL)"
200	default n
201	depends on (MODE_TT && EXPERIMENTAL && !SMP_BROKEN) || (BROKEN && SMP_BROKEN)
202	help
203	This option enables UML SMP support.
204	It is NOT related to having a real SMP box. Not directly, at least.
205
206	UML implements virtual SMP by allowing as many processes to run
207	simultaneously on the host as there are virtual processors configured.
208
209	Obviously, if the host is a uniprocessor, those processes will
210	timeshare, but, inside UML, will appear to be running simultaneously.
211	If the host is a multiprocessor, then UML processes may run
212	simultaneously, depending on the host scheduler.
213
214	This, however, is supported only in TT mode. So, if you use the SKAS
215	patch on your host, switching to TT mode and enabling SMP usually gives
216	you worse performances.
217	Also, since the support for SMP has been under-developed, there could
218	be some bugs being exposed by enabling SMP.
219
220	If you don't know what to do, say N.
221
222config NR_CPUS
223	int "Maximum number of CPUs (2-32)"
224	range 2 32
225	depends on SMP
226	default "32"
227
228config NEST_LEVEL
229	int "Nesting level"
230	default "0"
231	help
232        This is set to the number of layers of UMLs that this UML will be run
233        in.  Normally, this is zero, meaning that it will run directly on the
234        host.  Setting it to one will build a UML that can run inside a UML
235        that is running on the host.  Generally, if you intend this UML to run
236        inside another UML, set CONFIG_NEST_LEVEL to one more than the host
237        UML.
238
239        Note that if the hosting UML has its CONFIG_KERNEL_HALF_GIGS set to
240        greater than one, then the guest UML should have its CONFIG_NEST_LEVEL
241        set to the host's CONFIG_NEST_LEVEL + CONFIG_KERNEL_HALF_GIGS.
242        Only change this if you are running nested UMLs.
243
244config KERNEL_HALF_GIGS
245	int "Kernel address space size (in .5G units)"
246	default "1"
247	help
248        This determines the amount of address space that UML will allocate for
249        its own, measured in half Gigabyte units.  The default is 1.
250        Change this only if you need to boot UML with an unusually large amount
251        of physical memory.
252
253config HIGHMEM
254	bool "Highmem support"
255	depends on !64BIT
256
257config KERNEL_STACK_ORDER
258	int "Kernel stack size order"
259	default 2
260	help
261	This option determines the size of UML kernel stacks.  They will
262	be 1 << order pages.  The default is OK unless you're running Valgrind
263	on UML, in which case, set this to 3.
264
265config UML_REAL_TIME_CLOCK
266	bool "Real-time Clock"
267	default y
268	help
269	This option makes UML time deltas match wall clock deltas.  This should
270	normally be enabled.  The exception would be if you are debugging with
271	UML and spend long times with UML stopped at a breakpoint.  In this
272	case, when UML is restarted, it will call the timer enough times to make
273	up for the time spent at the breakpoint.  This could result in a
274	noticable lag.  If this is a problem, then disable this option.
275
276endmenu
277
278source "init/Kconfig"
279
280source "net/Kconfig"
281
282source "drivers/base/Kconfig"
283
284source "arch/um/Kconfig.char"
285
286source "drivers/block/Kconfig"
287
288config NETDEVICES
289	bool
290	default NET
291
292source "arch/um/Kconfig.net"
293
294source "drivers/net/Kconfig"
295
296source "fs/Kconfig"
297
298source "security/Kconfig"
299
300source "crypto/Kconfig"
301
302source "lib/Kconfig"
303
304menu "SCSI support"
305depends on BROKEN
306
307config SCSI
308	tristate "SCSI support"
309
310# This gives us free_dma, which scsi.c wants.
311config GENERIC_ISA_DMA
312	bool
313	depends on SCSI
314	default y
315
316source "arch/um/Kconfig.scsi"
317
318endmenu
319
320source "drivers/md/Kconfig"
321
322if BROKEN
323	source "drivers/mtd/Kconfig"
324endif
325
326#This is just to shut up some Kconfig warnings, so no prompt.
327config INPUT
328	bool
329	default n
330
331source "arch/um/Kconfig.debug"
332