Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1# SPDX-License-Identifier: GPL-2.0
2
3menu "UML-specific options"
4
5config UML
6 bool
7 default y
8 select ARCH_DISABLE_KASAN_INLINE if STATIC_LINK
9 select ARCH_NEEDS_DEFER_KASAN if STATIC_LINK
10 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
11 select ARCH_HAS_CACHE_LINE_SIZE
12 select ARCH_HAS_CPU_FINALIZE_INIT
13 select ARCH_HAS_FORTIFY_SOURCE
14 select ARCH_HAS_GCOV_PROFILE_ALL
15 select ARCH_HAS_KCOV
16 select ARCH_HAS_STRNCPY_FROM_USER
17 select ARCH_HAS_STRNLEN_USER
18 select ARCH_HAS_STRICT_KERNEL_RWX
19 select HAVE_ARCH_AUDITSYSCALL
20 select HAVE_ARCH_KASAN if X86_64
21 select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
22 select HAVE_ARCH_SECCOMP_FILTER
23 select HAVE_ASM_MODVERSIONS
24 select HAVE_UID16
25 select HAVE_DEBUG_KMEMLEAK
26 select HAVE_DEBUG_BUGVERBOSE
27 select HAVE_PAGE_SIZE_4KB
28 select NO_DMA if !UML_DMA_EMULATION
29 select OF_EARLY_FLATTREE if OF
30 select GENERIC_IRQ_SHOW
31 select GENERIC_CPU_DEVICES
32 select GENERIC_SMP_IDLE_THREAD
33 select HAVE_GCC_PLUGINS
34 select ARCH_SUPPORTS_LTO_CLANG
35 select ARCH_SUPPORTS_LTO_CLANG_THIN
36 select TRACE_IRQFLAGS_SUPPORT
37 select TTY # Needed for line.c
38 select HAVE_ARCH_VMAP_STACK
39 select HAVE_RUST
40 select ARCH_HAS_UBSAN
41 select HAVE_ARCH_TRACEHOOK
42 select HAVE_SYSCALL_TRACEPOINTS
43 select THREAD_INFO_IN_TASK
44 select SPARSE_IRQ
45 select MMU_GATHER_RCU_TABLE_FREE
46
47config MMU
48 bool
49 default y
50
51config UML_DMA_EMULATION
52 bool
53
54config NO_IOMEM
55 bool "disable IOMEM" if EXPERT
56 depends on !INDIRECT_IOMEM
57 default y
58
59config UML_IOMEM_EMULATION
60 bool
61 select INDIRECT_IOMEM
62 select GENERIC_PCI_IOMAP
63
64config ISA
65 bool
66
67config SBUS
68 bool
69
70config LOCKDEP_SUPPORT
71 bool
72 default y
73
74config STACKTRACE_SUPPORT
75 bool
76 default y
77 select STACKTRACE
78
79config GENERIC_CALIBRATE_DELAY
80 bool
81 default y
82
83config HZ
84 int
85 default 100
86
87config UML_SUBARCH_SUPPORTS_SMP
88 bool
89
90config SMP
91 bool "Symmetric multi-processing support"
92 default n
93 depends on UML_SUBARCH_SUPPORTS_SMP
94 help
95 This option enables UML SMP support.
96
97 With this enabled, users can tell UML to start multiple virtual
98 processors. Each virtual processor is represented as a separate
99 host thread.
100
101 In UML, kthreads and normal threads (when running in kernel mode)
102 can be scheduled and executed simultaneously on different virtual
103 processors. However, the userspace code of normal threads still
104 runs within their respective single-threaded stubs.
105
106 That is, SMP support is available both within the kernel and
107 across different processes, but remains limited within threads
108 of the same process in userspace.
109
110config NR_CPUS_RANGE_BEGIN
111 int
112 default 1 if !SMP
113 default 2
114
115config NR_CPUS_RANGE_END
116 int
117 default 1 if !SMP
118 default 64
119
120config NR_CPUS_DEFAULT
121 int
122 default 1 if !SMP
123 default 2
124
125config NR_CPUS
126 int "Maximum number of CPUs" if SMP
127 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
128 default NR_CPUS_DEFAULT
129
130source "arch/$(HEADER_ARCH)/um/Kconfig"
131
132config MAY_HAVE_RUNTIME_DEPS
133 bool
134
135config STATIC_LINK
136 bool "Force a static link"
137 depends on !MAY_HAVE_RUNTIME_DEPS
138 help
139 This option gives you the ability to force a static link of UML.
140 Normally, UML is linked as a shared binary. This is inconvenient for
141 use in a chroot jail. So, if you intend to run UML inside a chroot,
142 you probably want to say Y here.
143 Additionally, this option enables using higher memory spaces (up to
144 2.75G) for UML.
145
146 NOTE: This option is incompatible with some networking features which
147 depend on features that require being dynamically loaded (like NSS).
148
149config LD_SCRIPT_STATIC
150 bool
151 default y
152 depends on STATIC_LINK
153
154config LD_SCRIPT_DYN
155 bool
156 default y
157 depends on !LD_SCRIPT_STATIC
158
159config LD_SCRIPT_DYN_RPATH
160 bool "set rpath in the binary" if EXPERT
161 default y
162 depends on LD_SCRIPT_DYN
163 help
164 Add /lib (and /lib64 for 64-bit) to the linux binary's rpath
165 explicitly.
166
167 You may need to turn this off if compiling for nix systems
168 that have their libraries in random /nix directories and
169 might otherwise unexpected use libraries from /lib or /lib64
170 instead of the desired ones.
171
172config HOSTFS
173 tristate "Host filesystem"
174 help
175 While the User-Mode Linux port uses its own root file system for
176 booting and normal file access, this module lets the UML user
177 access files stored on the host. It does not require any
178 network connection between the Host and UML. An example use of
179 this might be:
180
181 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
182
183 where /tmp/fromhost is an empty directory inside UML and
184 /tmp/umlshare is a directory on the host with files the UML user
185 wishes to access.
186
187 For more information, see
188 <http://user-mode-linux.sourceforge.net/hostfs.html>.
189
190 If you'd like to be able to work with files stored on the host,
191 say Y or M here; otherwise say N.
192
193config MCONSOLE
194 bool "Management console"
195 depends on PROC_FS
196 default y
197 help
198 The user mode linux management console is a low-level interface to
199 the kernel, somewhat like the i386 SysRq interface. Since there is
200 a full-blown operating system running under every user mode linux
201 instance, there is much greater flexibility possible than with the
202 SysRq mechanism.
203
204 If you answer 'Y' to this option, to use this feature, you need the
205 mconsole client (called uml_mconsole) which is present in CVS in
206 2.4.5-9um and later (path /tools/mconsole), and is also in the
207 distribution RPM package in 2.4.6 and later.
208
209 It is safe to say 'Y' here.
210
211config MAGIC_SYSRQ
212 bool "Magic SysRq key"
213 depends on MCONSOLE
214 help
215 If you say Y here, you will have some control over the system even
216 if the system crashes for example during kernel debugging (e.g., you
217 will be able to flush the buffer cache to disk, reboot the system
218 immediately or dump some status information). A key for each of the
219 possible requests is provided.
220
221 This is the feature normally accomplished by pressing a key
222 while holding SysRq (Alt+PrintScreen).
223
224 On UML, this is accomplished by sending a "sysrq" command with
225 mconsole, followed by the letter for the requested command.
226
227 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y
228 unless you really know what this hack does.
229
230config KERNEL_STACK_ORDER
231 int "Kernel stack size order"
232 default 2 if 64BIT
233 range 2 10 if 64BIT
234 default 1 if !64BIT
235 help
236 This option determines the size of UML kernel stacks. They will
237 be 1 << order pages. The default is OK unless you're running Valgrind
238 on UML, in which case, set this to 3.
239 It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on
240 older (pre-2017) CPUs. It is not recommended on newer CPUs due to the
241 increase in the size of the state which needs to be saved when handling
242 signals.
243
244config PGTABLE_LEVELS
245 int
246 default 4 if 64BIT
247 default 2 if !64BIT
248
249config UML_TIME_TRAVEL_SUPPORT
250 bool
251 prompt "Support time-travel mode (e.g. for test execution)"
252 # inf-cpu mode is incompatible with the benchmarking
253 depends on !RAID6_PQ_BENCHMARK
254 depends on !SMP
255 help
256 Enable this option to support time travel inside the UML instance.
257
258 After enabling this option, two modes are accessible at runtime
259 (selected by the kernel command line), see the kernel's command-
260 line help for more details.
261
262 It is safe to say Y, but you probably don't need this.
263
264config UML_MAX_USERSPACE_ITERATIONS
265 int
266 prompt "Maximum number of unscheduled userspace iterations"
267 default 10000
268 depends on UML_TIME_TRAVEL_SUPPORT
269 help
270 In UML inf-cpu and ext time-travel mode userspace can run without being
271 interrupted. This will eventually overwhelm the kernel and create OOM
272 situations (mainly RCU not running). This setting specifies the number
273 of kernel/userspace switches (minor/major page fault, signal or syscall)
274 for the same userspace thread before the sched_clock is advanced by a
275 jiffie to trigger scheduling.
276
277 Setting it to zero disables the feature.
278
279config KASAN_SHADOW_OFFSET
280 hex
281 depends on KASAN
282 default 0x100000000000
283 help
284 This is the offset at which the ~16TB of shadow memory is
285 mapped and used by KASAN for memory debugging. This can be any
286 address that has at least KASAN_SHADOW_SIZE (total address space divided
287 by 8) amount of space so that the KASAN shadow memory does not conflict
288 with anything. The default is 0x100000000000, which works even if mem is
289 set to a large value. On low-memory systems, try 0x7fff8000, as it fits
290 into the immediate of most instructions, improving performance.
291
292endmenu
293
294source "arch/um/drivers/Kconfig"
295
296config ARCH_SUSPEND_POSSIBLE
297 def_bool y
298 depends on !SMP
299
300menu "Power management options"
301
302source "kernel/power/Kconfig"
303
304endmenu