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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_HAS_KCOV
9 select ARCH_NO_PREEMPT
10 select HAVE_ARCH_AUDITSYSCALL
11 select HAVE_ARCH_SECCOMP_FILTER
12 select HAVE_ASM_MODVERSIONS
13 select HAVE_UID16
14 select HAVE_FUTEX_CMPXCHG if FUTEX
15 select HAVE_DEBUG_KMEMLEAK
16 select HAVE_DEBUG_BUGVERBOSE
17 select NO_DMA
18 select GENERIC_IRQ_SHOW
19 select GENERIC_CPU_DEVICES
20 select GENERIC_CLOCKEVENTS
21 select HAVE_GCC_PLUGINS
22 select TTY # Needed for line.c
23
24config MMU
25 bool
26 default y
27
28config NO_IOMEM
29 def_bool y
30
31config ISA
32 bool
33
34config SBUS
35 bool
36
37config TRACE_IRQFLAGS_SUPPORT
38 bool
39 default y
40
41config LOCKDEP_SUPPORT
42 bool
43 default y
44
45config STACKTRACE_SUPPORT
46 bool
47 default y
48 select STACKTRACE
49
50config GENERIC_CALIBRATE_DELAY
51 bool
52 default y
53
54config HZ
55 int
56 default 100
57
58config NR_CPUS
59 int
60 range 1 1
61 default 1
62
63source "arch/$(HEADER_ARCH)/um/Kconfig"
64
65config FORBID_STATIC_LINK
66 bool
67
68config STATIC_LINK
69 bool "Force a static link"
70 depends on !FORBID_STATIC_LINK
71 help
72 This option gives you the ability to force a static link of UML.
73 Normally, UML is linked as a shared binary. This is inconvenient for
74 use in a chroot jail. So, if you intend to run UML inside a chroot,
75 you probably want to say Y here.
76 Additionally, this option enables using higher memory spaces (up to
77 2.75G) for UML.
78
79 NOTE: This option is incompatible with some networking features which
80 depend on features that require being dynamically loaded (like NSS).
81
82config LD_SCRIPT_STATIC
83 bool
84 default y
85 depends on STATIC_LINK
86
87config LD_SCRIPT_DYN
88 bool
89 default y
90 depends on !LD_SCRIPT_STATIC
91 select MODULE_REL_CRCS if MODVERSIONS
92
93config HOSTFS
94 tristate "Host filesystem"
95 help
96 While the User-Mode Linux port uses its own root file system for
97 booting and normal file access, this module lets the UML user
98 access files stored on the host. It does not require any
99 network connection between the Host and UML. An example use of
100 this might be:
101
102 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
103
104 where /tmp/fromhost is an empty directory inside UML and
105 /tmp/umlshare is a directory on the host with files the UML user
106 wishes to access.
107
108 For more information, see
109 <http://user-mode-linux.sourceforge.net/hostfs.html>.
110
111 If you'd like to be able to work with files stored on the host,
112 say Y or M here; otherwise say N.
113
114config MCONSOLE
115 bool "Management console"
116 depends on PROC_FS
117 default y
118 help
119 The user mode linux management console is a low-level interface to
120 the kernel, somewhat like the i386 SysRq interface. Since there is
121 a full-blown operating system running under every user mode linux
122 instance, there is much greater flexibility possible than with the
123 SysRq mechanism.
124
125 If you answer 'Y' to this option, to use this feature, you need the
126 mconsole client (called uml_mconsole) which is present in CVS in
127 2.4.5-9um and later (path /tools/mconsole), and is also in the
128 distribution RPM package in 2.4.6 and later.
129
130 It is safe to say 'Y' here.
131
132config MAGIC_SYSRQ
133 bool "Magic SysRq key"
134 depends on MCONSOLE
135 help
136 If you say Y here, you will have some control over the system even
137 if the system crashes for example during kernel debugging (e.g., you
138 will be able to flush the buffer cache to disk, reboot the system
139 immediately or dump some status information). A key for each of the
140 possible requests is provided.
141
142 This is the feature normally accomplished by pressing a key
143 while holding SysRq (Alt+PrintScreen).
144
145 On UML, this is accomplished by sending a "sysrq" command with
146 mconsole, followed by the letter for the requested command.
147
148 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y
149 unless you really know what this hack does.
150
151config KERNEL_STACK_ORDER
152 int "Kernel stack size order"
153 default 2 if 64BIT
154 range 2 10 if 64BIT
155 default 1 if !64BIT
156 help
157 This option determines the size of UML kernel stacks. They will
158 be 1 << order pages. The default is OK unless you're running Valgrind
159 on UML, in which case, set this to 3.
160 It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on
161 older (pre-2017) CPUs. It is not recommended on newer CPUs due to the
162 increase in the size of the state which needs to be saved when handling
163 signals.
164
165config MMAPPER
166 tristate "iomem emulation driver"
167 help
168 This driver allows a host file to be used as emulated IO memory inside
169 UML.
170
171config PGTABLE_LEVELS
172 int
173 default 3 if 3_LEVEL_PGTABLES
174 default 2
175
176config SECCOMP
177 def_bool y
178 prompt "Enable seccomp to safely compute untrusted bytecode"
179 help
180 This kernel feature is useful for number crunching applications
181 that may need to compute untrusted bytecode during their
182 execution. By using pipes or other transports made available to
183 the process as file descriptors supporting the read/write
184 syscalls, it's possible to isolate those applications in
185 their own address space using seccomp. Once seccomp is
186 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
187 and the task is only allowed to execute a few safe syscalls
188 defined by each seccomp mode.
189
190 If unsure, say Y.
191
192config UML_TIME_TRAVEL_SUPPORT
193 bool
194 prompt "Support time-travel mode (e.g. for test execution)"
195 # inf-cpu mode is incompatible with the benchmarking
196 depends on !RAID6_PQ_BENCHMARK
197 depends on !SMP
198 help
199 Enable this option to support time travel inside the UML instance.
200
201 After enabling this option, two modes are accessible at runtime
202 (selected by the kernel command line), see the kernel's command-
203 line help for more details.
204
205 It is safe to say Y, but you probably don't need this.
206
207endmenu
208
209source "arch/um/drivers/Kconfig"
1# SPDX-License-Identifier: GPL-2.0
2
3menu "UML-specific options"
4
5config UML
6 bool
7 default y
8 select ARCH_HAS_CPU_FINALIZE_INIT
9 select ARCH_HAS_FORTIFY_SOURCE
10 select ARCH_HAS_GCOV_PROFILE_ALL
11 select ARCH_HAS_KCOV
12 select ARCH_HAS_STRNCPY_FROM_USER
13 select ARCH_HAS_STRNLEN_USER
14 select ARCH_NO_PREEMPT
15 select HAVE_ARCH_AUDITSYSCALL
16 select HAVE_ARCH_KASAN if X86_64
17 select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
18 select HAVE_ARCH_SECCOMP_FILTER
19 select HAVE_ASM_MODVERSIONS
20 select HAVE_UID16
21 select HAVE_DEBUG_KMEMLEAK
22 select HAVE_DEBUG_BUGVERBOSE
23 select NO_DMA if !UML_DMA_EMULATION
24 select OF_EARLY_FLATTREE if OF
25 select GENERIC_IRQ_SHOW
26 select GENERIC_CPU_DEVICES
27 select HAVE_GCC_PLUGINS
28 select ARCH_SUPPORTS_LTO_CLANG
29 select ARCH_SUPPORTS_LTO_CLANG_THIN
30 select TRACE_IRQFLAGS_SUPPORT
31 select TTY # Needed for line.c
32 select HAVE_ARCH_VMAP_STACK
33 select HAVE_RUST if X86_64
34
35config MMU
36 bool
37 default y
38
39config UML_DMA_EMULATION
40 bool
41
42config NO_IOMEM
43 bool "disable IOMEM" if EXPERT
44 depends on !INDIRECT_IOMEM
45 default y
46
47config UML_IOMEM_EMULATION
48 bool
49 select INDIRECT_IOMEM
50 select GENERIC_PCI_IOMAP
51 select GENERIC_IOMAP
52 select NO_GENERIC_PCI_IOPORT_MAP
53
54config NO_IOPORT_MAP
55 def_bool y
56
57config ISA
58 bool
59
60config SBUS
61 bool
62
63config LOCKDEP_SUPPORT
64 bool
65 default y
66
67config STACKTRACE_SUPPORT
68 bool
69 default y
70 select STACKTRACE
71
72config GENERIC_CALIBRATE_DELAY
73 bool
74 default y
75
76config HZ
77 int
78 default 100
79
80config NR_CPUS
81 int
82 range 1 1
83 default 1
84
85config ARCH_HAS_CACHE_LINE_SIZE
86 def_bool y
87
88source "arch/$(HEADER_ARCH)/um/Kconfig"
89
90config MAY_HAVE_RUNTIME_DEPS
91 bool
92
93config STATIC_LINK
94 bool "Force a static link"
95 depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS
96 help
97 This option gives you the ability to force a static link of UML.
98 Normally, UML is linked as a shared binary. This is inconvenient for
99 use in a chroot jail. So, if you intend to run UML inside a chroot,
100 you probably want to say Y here.
101 Additionally, this option enables using higher memory spaces (up to
102 2.75G) for UML.
103
104 NOTE: This option is incompatible with some networking features which
105 depend on features that require being dynamically loaded (like NSS).
106
107config LD_SCRIPT_STATIC
108 bool
109 default y
110 depends on STATIC_LINK
111
112config LD_SCRIPT_DYN
113 bool
114 default y
115 depends on !LD_SCRIPT_STATIC
116
117config LD_SCRIPT_DYN_RPATH
118 bool "set rpath in the binary" if EXPERT
119 default y
120 depends on LD_SCRIPT_DYN
121 help
122 Add /lib (and /lib64 for 64-bit) to the linux binary's rpath
123 explicitly.
124
125 You may need to turn this off if compiling for nix systems
126 that have their libraries in random /nix directories and
127 might otherwise unexpected use libraries from /lib or /lib64
128 instead of the desired ones.
129
130config HOSTFS
131 tristate "Host filesystem"
132 help
133 While the User-Mode Linux port uses its own root file system for
134 booting and normal file access, this module lets the UML user
135 access files stored on the host. It does not require any
136 network connection between the Host and UML. An example use of
137 this might be:
138
139 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
140
141 where /tmp/fromhost is an empty directory inside UML and
142 /tmp/umlshare is a directory on the host with files the UML user
143 wishes to access.
144
145 For more information, see
146 <http://user-mode-linux.sourceforge.net/hostfs.html>.
147
148 If you'd like to be able to work with files stored on the host,
149 say Y or M here; otherwise say N.
150
151config MCONSOLE
152 bool "Management console"
153 depends on PROC_FS
154 default y
155 help
156 The user mode linux management console is a low-level interface to
157 the kernel, somewhat like the i386 SysRq interface. Since there is
158 a full-blown operating system running under every user mode linux
159 instance, there is much greater flexibility possible than with the
160 SysRq mechanism.
161
162 If you answer 'Y' to this option, to use this feature, you need the
163 mconsole client (called uml_mconsole) which is present in CVS in
164 2.4.5-9um and later (path /tools/mconsole), and is also in the
165 distribution RPM package in 2.4.6 and later.
166
167 It is safe to say 'Y' here.
168
169config MAGIC_SYSRQ
170 bool "Magic SysRq key"
171 depends on MCONSOLE
172 help
173 If you say Y here, you will have some control over the system even
174 if the system crashes for example during kernel debugging (e.g., you
175 will be able to flush the buffer cache to disk, reboot the system
176 immediately or dump some status information). A key for each of the
177 possible requests is provided.
178
179 This is the feature normally accomplished by pressing a key
180 while holding SysRq (Alt+PrintScreen).
181
182 On UML, this is accomplished by sending a "sysrq" command with
183 mconsole, followed by the letter for the requested command.
184
185 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y
186 unless you really know what this hack does.
187
188config KERNEL_STACK_ORDER
189 int "Kernel stack size order"
190 default 2 if 64BIT
191 range 2 10 if 64BIT
192 default 1 if !64BIT
193 help
194 This option determines the size of UML kernel stacks. They will
195 be 1 << order pages. The default is OK unless you're running Valgrind
196 on UML, in which case, set this to 3.
197 It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on
198 older (pre-2017) CPUs. It is not recommended on newer CPUs due to the
199 increase in the size of the state which needs to be saved when handling
200 signals.
201
202config MMAPPER
203 tristate "iomem emulation driver"
204 help
205 This driver allows a host file to be used as emulated IO memory inside
206 UML.
207
208config PGTABLE_LEVELS
209 int
210 default 3 if 3_LEVEL_PGTABLES
211 default 2
212
213config UML_TIME_TRAVEL_SUPPORT
214 bool
215 prompt "Support time-travel mode (e.g. for test execution)"
216 # inf-cpu mode is incompatible with the benchmarking
217 depends on !RAID6_PQ_BENCHMARK
218 depends on !SMP
219 help
220 Enable this option to support time travel inside the UML instance.
221
222 After enabling this option, two modes are accessible at runtime
223 (selected by the kernel command line), see the kernel's command-
224 line help for more details.
225
226 It is safe to say Y, but you probably don't need this.
227
228config KASAN_SHADOW_OFFSET
229 hex
230 depends on KASAN
231 default 0x100000000000
232 help
233 This is the offset at which the ~16TB of shadow memory is
234 mapped and used by KASAN for memory debugging. This can be any
235 address that has at least KASAN_SHADOW_SIZE (total address space divided
236 by 8) amount of space so that the KASAN shadow memory does not conflict
237 with anything. The default is 0x100000000000, which works even if mem is
238 set to a large value. On low-memory systems, try 0x7fff8000, as it fits
239 into the immediate of most instructions, improving performance.
240
241endmenu
242
243source "arch/um/drivers/Kconfig"
244
245config ARCH_SUSPEND_POSSIBLE
246 def_bool y
247
248menu "Power management options"
249
250source "kernel/power/Kconfig"
251
252endmenu