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 TRACE_IRQFLAGS_SUPPORT
26 select TTY # Needed for line.c
27 select HAVE_ARCH_VMAP_STACK
33 config UML_DMA_EMULATION
37 bool "disable IOMEM" if EXPERT
38 depends on !INDIRECT_IOMEM
41 config UML_IOMEM_EMULATION
44 select GENERIC_PCI_IOMAP
46 select NO_GENERIC_PCI_IOPORT_MAP
57 config LOCKDEP_SUPPORT
61 config STACKTRACE_SUPPORT
66 config GENERIC_CALIBRATE_DELAY
79 config ARCH_HAS_CACHE_LINE_SIZE
82 source "arch/$(HEADER_ARCH)/um/Kconfig"
84 config MAY_HAVE_RUNTIME_DEPS
88 bool "Force a static link"
89 depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS
91 This option gives you the ability to force a static link of UML.
92 Normally, UML is linked as a shared binary. This is inconvenient for
93 use in a chroot jail. So, if you intend to run UML inside a chroot,
94 you probably want to say Y here.
95 Additionally, this option enables using higher memory spaces (up to
98 NOTE: This option is incompatible with some networking features which
99 depend on features that require being dynamically loaded (like NSS).
101 config LD_SCRIPT_STATIC
104 depends on STATIC_LINK
109 depends on !LD_SCRIPT_STATIC
110 select MODULE_REL_CRCS if MODVERSIONS
112 config LD_SCRIPT_DYN_RPATH
113 bool "set rpath in the binary" if EXPERT
115 depends on LD_SCRIPT_DYN
117 Add /lib (and /lib64 for 64-bit) to the linux binary's rpath
120 You may need to turn this off if compiling for nix systems
121 that have their libraries in random /nix directories and
122 might otherwise unexpected use libraries from /lib or /lib64
123 instead of the desired ones.
126 tristate "Host filesystem"
128 While the User-Mode Linux port uses its own root file system for
129 booting and normal file access, this module lets the UML user
130 access files stored on the host. It does not require any
131 network connection between the Host and UML. An example use of
134 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
136 where /tmp/fromhost is an empty directory inside UML and
137 /tmp/umlshare is a directory on the host with files the UML user
140 For more information, see
141 <http://user-mode-linux.sourceforge.net/hostfs.html>.
143 If you'd like to be able to work with files stored on the host,
144 say Y or M here; otherwise say N.
147 bool "Management console"
151 The user mode linux management console is a low-level interface to
152 the kernel, somewhat like the i386 SysRq interface. Since there is
153 a full-blown operating system running under every user mode linux
154 instance, there is much greater flexibility possible than with the
157 If you answer 'Y' to this option, to use this feature, you need the
158 mconsole client (called uml_mconsole) which is present in CVS in
159 2.4.5-9um and later (path /tools/mconsole), and is also in the
160 distribution RPM package in 2.4.6 and later.
162 It is safe to say 'Y' here.
165 bool "Magic SysRq key"
168 If you say Y here, you will have some control over the system even
169 if the system crashes for example during kernel debugging (e.g., you
170 will be able to flush the buffer cache to disk, reboot the system
171 immediately or dump some status information). A key for each of the
172 possible requests is provided.
174 This is the feature normally accomplished by pressing a key
175 while holding SysRq (Alt+PrintScreen).
177 On UML, this is accomplished by sending a "sysrq" command with
178 mconsole, followed by the letter for the requested command.
180 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y
181 unless you really know what this hack does.
183 config KERNEL_STACK_ORDER
184 int "Kernel stack size order"
189 This option determines the size of UML kernel stacks. They will
190 be 1 << order pages. The default is OK unless you're running Valgrind
191 on UML, in which case, set this to 3.
192 It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on
193 older (pre-2017) CPUs. It is not recommended on newer CPUs due to the
194 increase in the size of the state which needs to be saved when handling
198 tristate "iomem emulation driver"
200 This driver allows a host file to be used as emulated IO memory inside
203 config PGTABLE_LEVELS
205 default 3 if 3_LEVEL_PGTABLES
208 config UML_TIME_TRAVEL_SUPPORT
210 prompt "Support time-travel mode (e.g. for test execution)"
211 # inf-cpu mode is incompatible with the benchmarking
212 depends on !RAID6_PQ_BENCHMARK
215 Enable this option to support time travel inside the UML instance.
217 After enabling this option, two modes are accessible at runtime
218 (selected by the kernel command line), see the kernel's command-
219 line help for more details.
221 It is safe to say Y, but you probably don't need this.
225 source "arch/um/drivers/Kconfig"
227 config ARCH_SUSPEND_POSSIBLE
230 source "kernel/power/Kconfig"