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1# SPDX-License-Identifier: GPL-2.0
2
3menu "UML-specific options"
4
5config UML
6	bool
7	default y
8	select ARCH_EPHEMERAL_INODES
9	select ARCH_HAS_CPU_FINALIZE_INIT
10	select ARCH_HAS_KCOV
11	select ARCH_HAS_STRNCPY_FROM_USER
12	select ARCH_HAS_STRNLEN_USER
13	select ARCH_NO_PREEMPT
14	select HAVE_ARCH_AUDITSYSCALL
15	select HAVE_ARCH_SECCOMP_FILTER
16	select HAVE_ASM_MODVERSIONS
17	select HAVE_UID16
18	select HAVE_FUTEX_CMPXCHG if FUTEX
19	select HAVE_DEBUG_KMEMLEAK
20	select HAVE_DEBUG_BUGVERBOSE
21	select NO_DMA if !UML_DMA_EMULATION
22	select GENERIC_IRQ_SHOW
23	select GENERIC_CPU_DEVICES
24	select HAVE_GCC_PLUGINS
25	select SET_FS
26	select TRACE_IRQFLAGS_SUPPORT
27	select TTY # Needed for line.c
28	select HAVE_ARCH_VMAP_STACK
29
30config MMU
31	bool
32	default y
33
34config UML_DMA_EMULATION
35	bool
36
37config NO_IOMEM
38	bool "disable IOMEM" if EXPERT
39	depends on !INDIRECT_IOMEM
40	default y
41
42config UML_IOMEM_EMULATION
43	bool
44	select INDIRECT_IOMEM
45	select GENERIC_PCI_IOMAP
46	select GENERIC_IOMAP
47	select NO_GENERIC_PCI_IOPORT_MAP
48
49config NO_IOPORT_MAP
50	def_bool y
51
52config ISA
53	bool
54
55config SBUS
56	bool
57
58config LOCKDEP_SUPPORT
59	bool
60	default y
61
62config STACKTRACE_SUPPORT
63	bool
64	default y
65	select STACKTRACE
66
67config GENERIC_CALIBRATE_DELAY
68	bool
69	default y
70
71config HZ
72	int
73	default 100
74
75config NR_CPUS
76	int
77	range 1 1
78	default 1
79
80config ARCH_HAS_CACHE_LINE_SIZE
81	def_bool y
82
83source "arch/$(HEADER_ARCH)/um/Kconfig"
84
85config MAY_HAVE_RUNTIME_DEPS
86        bool
87
88config STATIC_LINK
89	bool "Force a static link"
90	depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS
91	help
92	  This option gives you the ability to force a static link of UML.
93	  Normally, UML is linked as a shared binary.  This is inconvenient for
94	  use in a chroot jail.  So, if you intend to run UML inside a chroot,
95	  you probably want to say Y here.
96	  Additionally, this option enables using higher memory spaces (up to
97	  2.75G) for UML.
98
99	  NOTE: This option is incompatible with some networking features which
100	  depend on features that require being dynamically loaded (like NSS).
101
102config LD_SCRIPT_STATIC
103	bool
104	default y
105	depends on STATIC_LINK
106
107config LD_SCRIPT_DYN
108	bool
109	default y
110	depends on !LD_SCRIPT_STATIC
111	select MODULE_REL_CRCS if MODVERSIONS
112
113config LD_SCRIPT_DYN_RPATH
114	bool "set rpath in the binary" if EXPERT
115	default y
116	depends on LD_SCRIPT_DYN
117	help
118	  Add /lib (and /lib64 for 64-bit) to the linux binary's rpath
119	  explicitly.
120
121	  You may need to turn this off if compiling for nix systems
122	  that have their libraries in random /nix directories and
123	  might otherwise unexpected use libraries from /lib or /lib64
124	  instead of the desired ones.
125
126config HOSTFS
127	tristate "Host filesystem"
128	help
129	  While the User-Mode Linux port uses its own root file system for
130	  booting and normal file access, this module lets the UML user
131	  access files stored on the host.  It does not require any
132	  network connection between the Host and UML.  An example use of
133	  this might be:
134
135	  mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
136
137	  where /tmp/fromhost is an empty directory inside UML and
138	  /tmp/umlshare is a directory on the host with files the UML user
139	  wishes to access.
140
141	  For more information, see
142	  <http://user-mode-linux.sourceforge.net/hostfs.html>.
143
144	  If you'd like to be able to work with files stored on the host,
145	  say Y or M here; otherwise say N.
146
147config MCONSOLE
148	bool "Management console"
149	depends on PROC_FS
150	default y
151	help
152	  The user mode linux management console is a low-level interface to
153	  the kernel, somewhat like the i386 SysRq interface.  Since there is
154	  a full-blown operating system running under every user mode linux
155	  instance, there is much greater flexibility possible than with the
156	  SysRq mechanism.
157
158	  If you answer 'Y' to this option, to use this feature, you need the
159	  mconsole client (called uml_mconsole) which is present in CVS in
160	  2.4.5-9um and later (path /tools/mconsole), and is also in the
161	  distribution RPM package in 2.4.6 and later.
162
163	  It is safe to say 'Y' here.
164
165config MAGIC_SYSRQ
166	bool "Magic SysRq key"
167	depends on MCONSOLE
168	help
169	  If you say Y here, you will have some control over the system even
170	  if the system crashes for example during kernel debugging (e.g., you
171	  will be able to flush the buffer cache to disk, reboot the system
172	  immediately or dump some status information). A key for each of the
173	  possible requests is provided.
174
175	  This is the feature normally accomplished by pressing a key
176	  while holding SysRq (Alt+PrintScreen).
177
178	  On UML, this is accomplished by sending a "sysrq" command with
179	  mconsole, followed by the letter for the requested command.
180
181	  The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y
182	  unless you really know what this hack does.
183
184config KERNEL_STACK_ORDER
185	int "Kernel stack size order"
186	default 2 if 64BIT
187	range 2 10 if 64BIT
188	default 1 if !64BIT
189	help
190	  This option determines the size of UML kernel stacks.  They will
191	  be 1 << order pages.  The default is OK unless you're running Valgrind
192	  on UML, in which case, set this to 3.
193	  It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on
194	  older (pre-2017) CPUs. It is not recommended on newer CPUs due to the
195	  increase in the size of the state which needs to be saved when handling
196	  signals.
197
198config MMAPPER
199	tristate "iomem emulation driver"
200	help
201	  This driver allows a host file to be used as emulated IO memory inside
202	  UML.
203
204config PGTABLE_LEVELS
205	int
206	default 3 if 3_LEVEL_PGTABLES
207	default 2
208
209config UML_TIME_TRAVEL_SUPPORT
210	bool
211	prompt "Support time-travel mode (e.g. for test execution)"
212	# inf-cpu mode is incompatible with the benchmarking
213	depends on !RAID6_PQ_BENCHMARK
214	depends on !SMP
215	help
216	  Enable this option to support time travel inside the UML instance.
217
218	  After enabling this option, two modes are accessible at runtime
219	  (selected by the kernel command line), see the kernel's command-
220	  line help for more details.
221
222	  It is safe to say Y, but you probably don't need this.
223
224endmenu
225
226source "arch/um/drivers/Kconfig"
227
228config ARCH_SUSPEND_POSSIBLE
229	def_bool y
230
231source "kernel/power/Kconfig"
232