1 # SPDX-License-Identifier: GPL-2.0
3 menu "UML-specific options"
8 select ARCH_EPHEMERAL_INODES
10 select ARCH_HAS_STRNCPY_FROM_USER
11 select ARCH_HAS_STRNLEN_USER
12 select ARCH_NO_PREEMPT
13 select HAVE_ARCH_AUDITSYSCALL
14 select HAVE_ARCH_SECCOMP_FILTER
15 select HAVE_ASM_MODVERSIONS
17 select HAVE_FUTEX_CMPXCHG if FUTEX
18 select HAVE_DEBUG_KMEMLEAK
19 select HAVE_DEBUG_BUGVERBOSE
20 select NO_DMA if !UML_DMA_EMULATION
21 select GENERIC_IRQ_SHOW
22 select GENERIC_CPU_DEVICES
23 select HAVE_GCC_PLUGINS
25 select TTY # Needed for line.c
31 config UML_DMA_EMULATION
35 bool "disable IOMEM" if EXPERT
36 depends on !INDIRECT_IOMEM
39 config UML_IOMEM_EMULATION
42 select GENERIC_PCI_IOMAP
44 select NO_GENERIC_PCI_IOPORT_MAP
55 config TRACE_IRQFLAGS_SUPPORT
59 config LOCKDEP_SUPPORT
63 config STACKTRACE_SUPPORT
68 config GENERIC_CALIBRATE_DELAY
81 config ARCH_HAS_CACHE_LINE_SIZE
84 source "arch/$(HEADER_ARCH)/um/Kconfig"
86 config MAY_HAVE_RUNTIME_DEPS
90 bool "Force a static link"
91 depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS
93 This option gives you the ability to force a static link of UML.
94 Normally, UML is linked as a shared binary. This is inconvenient for
95 use in a chroot jail. So, if you intend to run UML inside a chroot,
96 you probably want to say Y here.
97 Additionally, this option enables using higher memory spaces (up to
100 NOTE: This option is incompatible with some networking features which
101 depend on features that require being dynamically loaded (like NSS).
103 config LD_SCRIPT_STATIC
106 depends on STATIC_LINK
111 depends on !LD_SCRIPT_STATIC
112 select MODULE_REL_CRCS if MODVERSIONS
114 config LD_SCRIPT_DYN_RPATH
115 bool "set rpath in the binary" if EXPERT
117 depends on LD_SCRIPT_DYN
119 Add /lib (and /lib64 for 64-bit) to the linux binary's rpath
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.
128 tristate "Host filesystem"
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
136 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
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
142 For more information, see
143 <http://user-mode-linux.sourceforge.net/hostfs.html>.
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.
149 bool "Management console"
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
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.
164 It is safe to say 'Y' here.
167 bool "Magic SysRq key"
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.
176 This is the feature normally accomplished by pressing a key
177 while holding SysRq (Alt+PrintScreen).
179 On UML, this is accomplished by sending a "sysrq" command with
180 mconsole, followed by the letter for the requested command.
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.
185 config KERNEL_STACK_ORDER
186 int "Kernel stack size order"
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
200 tristate "iomem emulation driver"
202 This driver allows a host file to be used as emulated IO memory inside
205 config PGTABLE_LEVELS
207 default 3 if 3_LEVEL_PGTABLES
210 config UML_TIME_TRAVEL_SUPPORT
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
217 Enable this option to support time travel inside the UML instance.
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.
223 It is safe to say Y, but you probably don't need this.
227 source "arch/um/drivers/Kconfig"
229 config ARCH_SUSPEND_POSSIBLE
232 source "kernel/power/Kconfig"