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