xref: /openbmc/linux/arch/um/Kconfig (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1config DEFCONFIG_LIST
2	string
3	option defconfig_list
4	default "arch/$ARCH/defconfig"
5
6# UML uses the generic IRQ sugsystem
7config GENERIC_HARDIRQS
8	bool
9	default y
10
11config UML
12	bool
13	default y
14
15config MMU
16	bool
17	default y
18
19config NO_IOMEM
20	def_bool y
21
22mainmenu "Linux/Usermode Kernel Configuration"
23
24config ISA
25	bool
26
27config SBUS
28	bool
29
30config PCI
31	bool
32
33config PCMCIA
34	bool
35
36# Yet to do!
37config TRACE_IRQFLAGS_SUPPORT
38	bool
39	default n
40
41config LOCKDEP_SUPPORT
42	bool
43	default y
44
45config STACKTRACE_SUPPORT
46	bool
47	default n
48
49config GENERIC_CALIBRATE_DELAY
50	bool
51	default y
52
53config GENERIC_BUG
54	bool
55	default y
56	depends on BUG
57
58# Used in kernel/irq/manage.c and include/linux/irq.h
59config IRQ_RELEASE_METHOD
60	bool
61	default y
62
63menu "UML-specific options"
64
65config MODE_TT
66	bool "Tracing thread support (DEPRECATED)"
67	default n
68	depends on BROKEN
69	help
70	This option controls whether tracing thread support is compiled
71	into UML. This option is largely obsolete, given that skas0 provides
72	skas security and performance without needing to patch the host.
73	It is safe to say 'N' here; saying 'Y' may cause additional problems
74	with the resulting binary even if you run UML in SKAS mode, and running
75	in TT mode is strongly *NOT RECOMMENDED*.
76
77config STATIC_LINK
78	bool "Force a static link"
79	default n
80	depends on !MODE_TT
81	help
82	If CONFIG_MODE_TT is disabled, then this option gives you the ability
83	to force a static link of UML.  Normally, if only skas mode is built
84	in to UML, it will be linked as a shared binary.  This is inconvenient
85	for use in a chroot jail.  So, if you intend to run UML inside a
86	chroot, and you disable CONFIG_MODE_TT, you probably want to say Y
87	here.
88	Additionally, this option enables using higher memory spaces (up to
89	2.75G) for UML - disabling CONFIG_MODE_TT and enabling this option leads
90	to best results for this.
91
92config KERNEL_HALF_GIGS
93	int "Kernel address space size (in .5G units)"
94	default "1"
95	depends on MODE_TT
96	help
97        This determines the amount of address space that UML will allocate for
98        its own, measured in half Gigabyte units.  The default is 1.
99        Change this only if you need to boot UML with an unusually large amount
100        of physical memory.
101
102config MODE_SKAS
103	bool "Separate Kernel Address Space support" if MODE_TT
104	default y
105	help
106	This option controls whether skas (separate kernel address space)
107	support is compiled in.
108	Unless you have specific needs to use TT mode (which applies almost only
109	to developers), you should say Y here.
110	SKAS mode will make use of the SKAS3 patch if it is applied on the host
111	(and your UML will run in SKAS3 mode), but if no SKAS patch is applied
112	on the host it will run in SKAS0 mode, which is anyway faster than TT
113	mode.
114
115source "arch/um/Kconfig.arch"
116source "mm/Kconfig"
117
118config LD_SCRIPT_STATIC
119	bool
120	default y
121	depends on MODE_TT || STATIC_LINK
122
123config LD_SCRIPT_DYN
124	bool
125	default y
126	depends on !LD_SCRIPT_STATIC
127
128config NET
129	bool "Networking support"
130	help
131	Unless you really know what you are doing, you should say Y here.
132	The reason is that some programs need kernel networking support even
133	when running on a stand-alone machine that isn't connected to any
134	other computer. If you are upgrading from an older kernel, you
135	should consider updating your networking tools too because changes
136	in the kernel and the tools often go hand in hand. The tools are
137	contained in the package net-tools, the location and version number
138	of which are given in <file:Documentation/Changes>.
139
140	For a general introduction to Linux networking, it is highly
141	recommended to read the NET-HOWTO, available from
142	<http://www.tldp.org/docs.html#howto>.
143
144
145source "fs/Kconfig.binfmt"
146
147config HOSTFS
148	tristate "Host filesystem"
149	help
150        While the User-Mode Linux port uses its own root file system for
151        booting and normal file access, this module lets the UML user
152        access files stored on the host.  It does not require any
153        network connection between the Host and UML.  An example use of
154        this might be:
155
156        mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
157
158        where /tmp/fromhost is an empty directory inside UML and
159        /tmp/umlshare is a directory on the host with files the UML user
160        wishes to access.
161
162        For more information, see
163        <http://user-mode-linux.sourceforge.net/hostfs.html>.
164
165        If you'd like to be able to work with files stored on the host,
166        say Y or M here; otherwise say N.
167
168config HPPFS
169	tristate "HoneyPot ProcFS (EXPERIMENTAL)"
170	depends on EXPERIMENTAL
171	help
172	hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
173	entries to be overridden, removed, or fabricated from the host.
174	Its purpose is to allow a UML to appear to be a physical machine
175	by removing or changing anything in /proc which gives away the
176	identity of a UML.
177
178	See <http://user-mode-linux.sf.net/hppfs.html> for more information.
179
180	You only need this if you are setting up a UML honeypot.  Otherwise,
181	it is safe to say 'N' here.
182
183config MCONSOLE
184	bool "Management console"
185	default y
186	help
187        The user mode linux management console is a low-level interface to
188        the kernel, somewhat like the i386 SysRq interface.  Since there is
189        a full-blown operating system running under every user mode linux
190        instance, there is much greater flexibility possible than with the
191        SysRq mechanism.
192
193        If you answer 'Y' to this option, to use this feature, you need the
194        mconsole client (called uml_mconsole) which is present in CVS in
195        2.4.5-9um and later (path /tools/mconsole), and is also in the
196        distribution RPM package in 2.4.6 and later.
197
198        It is safe to say 'Y' here.
199
200config MAGIC_SYSRQ
201	bool "Magic SysRq key"
202	depends on MCONSOLE
203	---help---
204	If you say Y here, you will have some control over the system even
205	if the system crashes for example during kernel debugging (e.g., you
206	will be able to flush the buffer cache to disk, reboot the system
207	immediately or dump some status information). A key for each of the
208	possible requests is provided.
209
210	This is the feature normally accomplished by pressing a key
211	while holding SysRq (Alt+PrintScreen).
212
213	On UML, this is accomplished by sending a "sysrq" command with
214	mconsole, followed by the letter for the requested command.
215
216	The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
217	unless you really know what this hack does.
218
219config SMP
220	bool "Symmetric multi-processing support (EXPERIMENTAL)"
221	default n
222	#SMP_BROKEN is for x86_64.
223	depends on MODE_TT && EXPERIMENTAL && (!SMP_BROKEN || (BROKEN && SMP_BROKEN))
224	help
225	This option enables UML SMP support.
226	It is NOT related to having a real SMP box. Not directly, at least.
227
228	UML implements virtual SMP by allowing as many processes to run
229	simultaneously on the host as there are virtual processors configured.
230
231	Obviously, if the host is a uniprocessor, those processes will
232	timeshare, but, inside UML, will appear to be running simultaneously.
233	If the host is a multiprocessor, then UML processes may run
234	simultaneously, depending on the host scheduler.
235
236	This, however, is supported only in TT mode. So, if you use the SKAS
237	patch on your host, switching to TT mode and enabling SMP usually gives
238	you worse performances.
239	Also, since the support for SMP has been under-developed, there could
240	be some bugs being exposed by enabling SMP.
241
242	If you don't know what to do, say N.
243
244config NR_CPUS
245	int "Maximum number of CPUs (2-32)"
246	range 2 32
247	depends on SMP
248	default "32"
249
250config NEST_LEVEL
251	int "Nesting level"
252	default "0"
253	help
254        This is set to the number of layers of UMLs that this UML will be run
255        in.  Normally, this is zero, meaning that it will run directly on the
256        host.  Setting it to one will build a UML that can run inside a UML
257        that is running on the host.  Generally, if you intend this UML to run
258        inside another UML, set CONFIG_NEST_LEVEL to one more than the host
259        UML.
260
261        Note that if the hosting UML has its CONFIG_KERNEL_HALF_GIGS set to
262        greater than one, then the guest UML should have its CONFIG_NEST_LEVEL
263        set to the host's CONFIG_NEST_LEVEL + CONFIG_KERNEL_HALF_GIGS.
264        Only change this if you are running nested UMLs.
265
266config HIGHMEM
267	bool "Highmem support (EXPERIMENTAL)"
268	depends on !64BIT && EXPERIMENTAL
269	default n
270	help
271	This was used to allow UML to run with big amounts of memory.
272	Currently it is unstable, so if unsure say N.
273
274	To use big amounts of memory, it is recommended to disable TT mode (i.e.
275	CONFIG_MODE_TT) and enable static linking (i.e. CONFIG_STATIC_LINK) -
276	this should allow the guest to use up to 2.75G of memory.
277
278config KERNEL_STACK_ORDER
279	int "Kernel stack size order"
280	default 1 if 64BIT
281	default 0 if !64BIT
282	help
283	This option determines the size of UML kernel stacks.  They will
284	be 1 << order pages.  The default is OK unless you're running Valgrind
285	on UML, in which case, set this to 3.
286
287config UML_REAL_TIME_CLOCK
288	bool "Real-time Clock"
289	default y
290	help
291	This option makes UML time deltas match wall clock deltas.  This should
292	normally be enabled.  The exception would be if you are debugging with
293	UML and spend long times with UML stopped at a breakpoint.  In this
294	case, when UML is restarted, it will call the timer enough times to make
295	up for the time spent at the breakpoint.  This could result in a
296	noticeable lag.  If this is a problem, then disable this option.
297
298endmenu
299
300source "init/Kconfig"
301
302source "drivers/block/Kconfig"
303
304source "arch/um/Kconfig.char"
305
306source "drivers/base/Kconfig"
307
308source "net/Kconfig"
309
310source "arch/um/Kconfig.net"
311
312source "drivers/net/Kconfig"
313
314source "drivers/connector/Kconfig"
315
316source "fs/Kconfig"
317
318source "security/Kconfig"
319
320source "crypto/Kconfig"
321
322source "lib/Kconfig"
323
324source "drivers/scsi/Kconfig"
325
326source "drivers/md/Kconfig"
327
328if BROKEN
329	source "drivers/mtd/Kconfig"
330endif
331
332#This is just to shut up some Kconfig warnings, so no prompt.
333config INPUT
334	bool
335	default n
336
337source "arch/um/Kconfig.debug"
338