xref: /openbmc/linux/arch/um/Kconfig (revision 87c2ce3b)
1# UML uses the generic IRQ sugsystem
2config GENERIC_HARDIRQS
3	bool
4	default y
5
6config UML
7	bool
8	default y
9
10config MMU
11	bool
12	default y
13
14mainmenu "Linux/Usermode Kernel Configuration"
15
16config ISA
17	bool
18
19config SBUS
20	bool
21
22config PCI
23	bool
24
25config GENERIC_CALIBRATE_DELAY
26	bool
27	default y
28
29# Used in kernel/irq/manage.c and include/linux/irq.h
30config IRQ_RELEASE_METHOD
31	bool
32	default y
33
34menu "UML-specific options"
35
36config MODE_TT
37	bool "Tracing thread support"
38	default y
39	help
40	This option controls whether tracing thread support is compiled
41	into UML.  Normally, this should be set to Y.  If you intend to
42	use only skas mode (and the host has the skas patch applied to it),
43	then it is OK to say N here.
44
45config STATIC_LINK
46	bool "Force a static link"
47	default n
48	depends on !MODE_TT
49	help
50	If CONFIG_MODE_TT is disabled, then this option gives you the ability
51	to force a static link of UML.  Normally, if only skas mode is built
52	in to UML, it will be linked as a shared binary.  This is inconvenient
53	for use in a chroot jail.  So, if you intend to run UML inside a
54	chroot, and you disable CONFIG_MODE_TT, you probably want to say Y
55	here.
56
57config HOST_2G_2G
58	bool "2G/2G host address space split"
59	default n
60	depends on MODE_TT
61	help
62	This is needed when the host on which you run has a 2G/2G memory
63	split, instead of the customary 3G/1G.
64
65	Note that to enable such a host
66	configuration, which makes sense only in some cases, you need special
67	host patches.
68
69	So, if you do not know what to do here, say 'N'.
70
71config KERNEL_HALF_GIGS
72	int "Kernel address space size (in .5G units)"
73	default "1"
74	depends on MODE_TT
75	help
76        This determines the amount of address space that UML will allocate for
77        its own, measured in half Gigabyte units.  The default is 1.
78        Change this only if you need to boot UML with an unusually large amount
79        of physical memory.
80
81config MODE_SKAS
82	bool "Separate Kernel Address Space support" if MODE_TT
83	default y
84	help
85	This option controls whether skas (separate kernel address space)
86	support is compiled in.  If you have applied the skas patch to the
87	host, then you certainly want to say Y here (and consider saying N
88	to CONFIG_MODE_TT).  Otherwise, it is safe to say Y.  Disabling this
89	option will shrink the UML binary slightly.
90
91source "arch/um/Kconfig.arch"
92source "mm/Kconfig"
93
94config LD_SCRIPT_STATIC
95	bool
96	default y
97	depends on MODE_TT || STATIC_LINK
98
99config LD_SCRIPT_DYN
100	bool
101	default y
102	depends on !LD_SCRIPT_STATIC
103
104config NET
105	bool "Networking support"
106	help
107	Unless you really know what you are doing, you should say Y here.
108	The reason is that some programs need kernel networking support even
109	when running on a stand-alone machine that isn't connected to any
110	other computer. If you are upgrading from an older kernel, you
111	should consider updating your networking tools too because changes
112	in the kernel and the tools often go hand in hand. The tools are
113	contained in the package net-tools, the location and version number
114	of which are given in <file:Documentation/Changes>.
115
116	For a general introduction to Linux networking, it is highly
117	recommended to read the NET-HOWTO, available from
118	<http://www.tldp.org/docs.html#howto>.
119
120
121source "fs/Kconfig.binfmt"
122
123config HOSTFS
124	tristate "Host filesystem"
125	help
126        While the User-Mode Linux port uses its own root file system for
127        booting and normal file access, this module lets the UML user
128        access files stored on the host.  It does not require any
129        network connection between the Host and UML.  An example use of
130        this might be:
131
132        mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
133
134        where /tmp/fromhost is an empty directory inside UML and
135        /tmp/umlshare is a directory on the host with files the UML user
136        wishes to access.
137
138        For more information, see
139        <http://user-mode-linux.sourceforge.net/hostfs.html>.
140
141        If you'd like to be able to work with files stored on the host,
142        say Y or M here; otherwise say N.
143
144config HPPFS
145	tristate "HoneyPot ProcFS (EXPERIMENTAL)"
146	help
147	hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
148	entries to be overridden, removed, or fabricated from the host.
149	Its purpose is to allow a UML to appear to be a physical machine
150	by removing or changing anything in /proc which gives away the
151	identity of a UML.
152
153	See <http://user-mode-linux.sf.net/hppfs.html> for more information.
154
155	You only need this if you are setting up a UML honeypot.  Otherwise,
156	it is safe to say 'N' here.
157
158	If you are actively using it, please report any problems, since it's
159	getting fixed. In this moment, it is experimental on 2.6 (it works on
160	2.4).
161
162config MCONSOLE
163	bool "Management console"
164	default y
165	help
166        The user mode linux management console is a low-level interface to
167        the kernel, somewhat like the i386 SysRq interface.  Since there is
168        a full-blown operating system running under every user mode linux
169        instance, there is much greater flexibility possible than with the
170        SysRq mechanism.
171
172        If you answer 'Y' to this option, to use this feature, you need the
173        mconsole client (called uml_mconsole) which is present in CVS in
174        2.4.5-9um and later (path /tools/mconsole), and is also in the
175        distribution RPM package in 2.4.6 and later.
176
177        It is safe to say 'Y' here.
178
179config MAGIC_SYSRQ
180	bool "Magic SysRq key"
181	depends on MCONSOLE
182	---help---
183	If you say Y here, you will have some control over the system even
184	if the system crashes for example during kernel debugging (e.g., you
185	will be able to flush the buffer cache to disk, reboot the system
186	immediately or dump some status information). A key for each of the
187	possible requests is provided.
188
189	This is the feature normally accomplished by pressing a key
190	while holding SysRq (Alt+PrintScreen).
191
192	On UML, this is accomplished by sending a "sysrq" command with
193	mconsole, followed by the letter for the requested command.
194
195	The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
196	unless you really know what this hack does.
197
198config SMP
199	bool "Symmetric multi-processing support (EXPERIMENTAL)"
200	default n
201	#SMP_BROKEN is for x86_64.
202	depends on MODE_TT && EXPERIMENTAL && (!SMP_BROKEN || (BROKEN && SMP_BROKEN))
203	help
204	This option enables UML SMP support.
205	It is NOT related to having a real SMP box. Not directly, at least.
206
207	UML implements virtual SMP by allowing as many processes to run
208	simultaneously on the host as there are virtual processors configured.
209
210	Obviously, if the host is a uniprocessor, those processes will
211	timeshare, but, inside UML, will appear to be running simultaneously.
212	If the host is a multiprocessor, then UML processes may run
213	simultaneously, depending on the host scheduler.
214
215	This, however, is supported only in TT mode. So, if you use the SKAS
216	patch on your host, switching to TT mode and enabling SMP usually gives
217	you worse performances.
218	Also, since the support for SMP has been under-developed, there could
219	be some bugs being exposed by enabling SMP.
220
221	If you don't know what to do, say N.
222
223config NR_CPUS
224	int "Maximum number of CPUs (2-32)"
225	range 2 32
226	depends on SMP
227	default "32"
228
229config NEST_LEVEL
230	int "Nesting level"
231	default "0"
232	help
233        This is set to the number of layers of UMLs that this UML will be run
234        in.  Normally, this is zero, meaning that it will run directly on the
235        host.  Setting it to one will build a UML that can run inside a UML
236        that is running on the host.  Generally, if you intend this UML to run
237        inside another UML, set CONFIG_NEST_LEVEL to one more than the host
238        UML.
239
240        Note that if the hosting UML has its CONFIG_KERNEL_HALF_GIGS set to
241        greater than one, then the guest UML should have its CONFIG_NEST_LEVEL
242        set to the host's CONFIG_NEST_LEVEL + CONFIG_KERNEL_HALF_GIGS.
243        Only change this if you are running nested UMLs.
244
245config HIGHMEM
246	bool "Highmem support"
247	depends on !64BIT
248
249config KERNEL_STACK_ORDER
250	int "Kernel stack size order"
251	default 2
252	help
253	This option determines the size of UML kernel stacks.  They will
254	be 1 << order pages.  The default is OK unless you're running Valgrind
255	on UML, in which case, set this to 3.
256
257config UML_REAL_TIME_CLOCK
258	bool "Real-time Clock"
259	default y
260	help
261	This option makes UML time deltas match wall clock deltas.  This should
262	normally be enabled.  The exception would be if you are debugging with
263	UML and spend long times with UML stopped at a breakpoint.  In this
264	case, when UML is restarted, it will call the timer enough times to make
265	up for the time spent at the breakpoint.  This could result in a
266	noticable lag.  If this is a problem, then disable this option.
267
268endmenu
269
270source "init/Kconfig"
271
272source "net/Kconfig"
273
274source "drivers/base/Kconfig"
275
276source "arch/um/Kconfig.char"
277
278source "drivers/block/Kconfig"
279
280config NETDEVICES
281	bool
282	default NET
283
284source "arch/um/Kconfig.net"
285
286source "drivers/net/Kconfig"
287
288source "drivers/connector/Kconfig"
289
290source "fs/Kconfig"
291
292source "security/Kconfig"
293
294source "crypto/Kconfig"
295
296source "lib/Kconfig"
297
298menu "SCSI support"
299depends on BROKEN
300
301config SCSI
302	tristate "SCSI support"
303
304# This gives us free_dma, which scsi.c wants.
305config GENERIC_ISA_DMA
306	bool
307	depends on SCSI
308	default y
309
310source "arch/um/Kconfig.scsi"
311
312endmenu
313
314source "drivers/md/Kconfig"
315
316if BROKEN
317	source "drivers/mtd/Kconfig"
318endif
319
320#This is just to shut up some Kconfig warnings, so no prompt.
321config INPUT
322	bool
323	default n
324
325source "arch/um/Kconfig.debug"
326