xref: /openbmc/linux/arch/um/Kconfig (revision 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2)
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 RWSEM_GENERIC_SPINLOCK
31	bool
32	default y
33
34config GENERIC_CALIBRATE_DELAY
35	bool
36	default y
37
38menu "UML-specific options"
39
40config MODE_TT
41	bool "Tracing thread support"
42	default y
43	help
44	This option controls whether tracing thread support is compiled
45	into UML.  Normally, this should be set to Y.  If you intend to
46	use only skas mode (and the host has the skas patch applied to it),
47	then it is OK to say N here.
48
49config STATIC_LINK
50	bool "Force a static link"
51	default n
52	depends on !MODE_TT
53	help
54	If CONFIG_MODE_TT is disabled, then this option gives you the ability
55	to force a static link of UML.  Normally, if only skas mode is built
56	in to UML, it will be linked as a shared binary.  This is inconvenient
57	for use in a chroot jail.  So, if you intend to run UML inside a
58	chroot, and you disable CONFIG_MODE_TT, you probably want to say Y
59	here.
60
61config MODE_SKAS
62	bool "Separate Kernel Address Space support"
63	default y
64	help
65	This option controls whether skas (separate kernel address space)
66	support is compiled in.  If you have applied the skas patch to the
67	host, then you certainly want to say Y here (and consider saying N
68	to CONFIG_MODE_TT).  Otherwise, it is safe to say Y.  Disabling this
69	option will shrink the UML binary slightly.
70
71source "arch/um/Kconfig_arch"
72
73config LD_SCRIPT_STATIC
74	bool
75	default y
76	depends on MODE_TT || STATIC_LINK
77
78config LD_SCRIPT_DYN
79	bool
80	default y
81	depends on !LD_SCRIPT_STATIC
82
83config NET
84	bool "Networking support"
85	help
86	Unless you really know what you are doing, you should say Y here.
87	The reason is that some programs need kernel networking support even
88	when running on a stand-alone machine that isn't connected to any
89	other computer. If you are upgrading from an older kernel, you
90	should consider updating your networking tools too because changes
91	in the kernel and the tools often go hand in hand. The tools are
92	contained in the package net-tools, the location and version number
93	of which are given in <file:Documentation/Changes>.
94
95	For a general introduction to Linux networking, it is highly
96	recommended to read the NET-HOWTO, available from
97	<http://www.tldp.org/docs.html#howto>.
98
99
100source "fs/Kconfig.binfmt"
101
102config HOSTFS
103	tristate "Host filesystem"
104	help
105        While the User-Mode Linux port uses its own root file system for
106        booting and normal file access, this module lets the UML user
107        access files stored on the host.  It does not require any
108        network connection between the Host and UML.  An example use of
109        this might be:
110
111        mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
112
113        where /tmp/fromhost is an empty directory inside UML and
114        /tmp/umlshare is a directory on the host with files the UML user
115        wishes to access.
116
117        For more information, see
118        <http://user-mode-linux.sourceforge.net/hostfs.html>.
119
120        If you'd like to be able to work with files stored on the host,
121        say Y or M here; otherwise say N.
122
123config HPPFS
124	tristate "HoneyPot ProcFS (EXPERIMENTAL)"
125	depends on BROKEN
126	help
127	hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
128	entries to be overridden, removed, or fabricated from the host.
129	Its purpose is to allow a UML to appear to be a physical machine
130	by removing or changing anything in /proc which gives away the
131	identity of a UML.
132
133	See <http://user-mode-linux.sf.net/hppfs.html> for more information.
134
135	You only need this if you are setting up a UML honeypot.  Otherwise,
136	it is safe to say 'N' here.
137
138	If you are actively using it, please ask for it to be fixed. In this
139	moment, it does not work on 2.6 (it works somehow on 2.4).
140
141config MCONSOLE
142	bool "Management console"
143	default y
144	help
145        The user mode linux management console is a low-level interface to
146        the kernel, somewhat like the i386 SysRq interface.  Since there is
147        a full-blown operating system running under every user mode linux
148        instance, there is much greater flexibility possible than with the
149        SysRq mechanism.
150
151        If you answer 'Y' to this option, to use this feature, you need the
152        mconsole client (called uml_mconsole) which is present in CVS in
153        2.4.5-9um and later (path /tools/mconsole), and is also in the
154        distribution RPM package in 2.4.6 and later.
155
156        It is safe to say 'Y' here.
157
158config MAGIC_SYSRQ
159	bool "Magic SysRq key"
160	depends on MCONSOLE
161	---help---
162	If you say Y here, you will have some control over the system even
163	if the system crashes for example during kernel debugging (e.g., you
164	will be able to flush the buffer cache to disk, reboot the system
165	immediately or dump some status information). A key for each of the
166	possible requests is provided.
167
168	This is the feature normally accomplished by pressing a key
169	while holding SysRq (Alt+PrintScreen).
170
171	On UML, this is accomplished by sending a "sysrq" command with
172	mconsole, followed by the letter for the requested command.
173
174	The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
175	unless you really know what this hack does.
176
177config HOST_2G_2G
178	bool "2G/2G host address space split"
179	default n
180	help
181	This is needed when the host on which you run has a 2G/2G memory
182	split, instead of the customary 3G/1G.
183
184	Note that to enable such a host
185	configuration, which makes sense only in some cases, you need special
186	host patches.
187
188	So, if you do not know what to do here, say 'N'.
189
190config SMP
191	bool "Symmetric multi-processing support (EXPERIMENTAL)"
192	default n
193	depends on MODE_TT && EXPERIMENTAL
194	help
195	This option enables UML SMP support.
196	It is NOT related to having a real SMP box. Not directly, at least.
197
198	UML implements virtual SMP by allowing as many processes to run
199	simultaneously on the host as there are virtual processors configured.
200
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.
205
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.
211
212	If you don't know what to do, say N.
213
214config NR_CPUS
215	int "Maximum number of CPUs (2-32)"
216	range 2 32
217	depends on SMP
218	default "32"
219
220config NEST_LEVEL
221	int "Nesting level"
222	default "0"
223	help
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
229        UML.
230
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.
235
236config KERNEL_HALF_GIGS
237	int "Kernel address space size (in .5G units)"
238	default "1"
239	help
240        This determines the amount of address space that UML will allocate for
241        its own, measured in half Gigabyte units.  The default is 1.
242        Change this only if you need to boot UML with an unusually large amount
243        of physical memory.
244
245config HIGHMEM
246	bool "Highmem support"
247
248config KERNEL_STACK_ORDER
249	int "Kernel stack size order"
250	default 2
251	help
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.
255
256config UML_REAL_TIME_CLOCK
257	bool "Real-time Clock"
258	default y
259	help
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.
266
267endmenu
268
269source "init/Kconfig"
270
271source "drivers/base/Kconfig"
272
273source "arch/um/Kconfig_char"
274
275source "drivers/block/Kconfig"
276
277config NETDEVICES
278	bool
279	default NET
280
281source "arch/um/Kconfig_net"
282
283source "net/Kconfig"
284
285source "fs/Kconfig"
286
287source "security/Kconfig"
288
289source "crypto/Kconfig"
290
291source "lib/Kconfig"
292
293menu "SCSI support"
294depends on BROKEN
295
296config SCSI
297	tristate "SCSI support"
298
299# This gives us free_dma, which scsi.c wants.
300config GENERIC_ISA_DMA
301	bool
302	depends on SCSI
303	default y
304
305source "arch/um/Kconfig_scsi"
306
307endmenu
308
309source "drivers/md/Kconfig"
310
311if BROKEN
312	source "drivers/mtd/Kconfig"
313endif
314
315#This is just to shut up some Kconfig warnings, so no prompt.
316config INPUT
317	bool
318	default n
319
320source "arch/um/Kconfig.debug"
321