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