1 # SPDX-License-Identifier: GPL-2.0
3 menu "UML-specific options"
8 select ARCH_EPHEMERAL_INODES
10 select ARCH_NO_PREEMPT
11 select HAVE_ARCH_AUDITSYSCALL
12 select HAVE_ARCH_SECCOMP_FILTER
13 select HAVE_ASM_MODVERSIONS
15 select HAVE_FUTEX_CMPXCHG if FUTEX
16 select HAVE_DEBUG_KMEMLEAK
17 select HAVE_DEBUG_BUGVERBOSE
18 select NO_DMA if !UML_DMA_EMULATION
19 select GENERIC_IRQ_SHOW
20 select GENERIC_CPU_DEVICES
21 select HAVE_GCC_PLUGINS
23 select TTY # Needed for line.c
24 select HAVE_ARCH_VMAP_STACK
30 config UML_DMA_EMULATION
34 bool "disable IOMEM" if EXPERT
35 depends on !INDIRECT_IOMEM
38 config UML_IOMEM_EMULATION
41 select GENERIC_PCI_IOMAP
43 select NO_GENERIC_PCI_IOPORT_MAP
54 config TRACE_IRQFLAGS_SUPPORT
58 config LOCKDEP_SUPPORT
62 config STACKTRACE_SUPPORT
67 config GENERIC_CALIBRATE_DELAY
80 config ARCH_HAS_CACHE_LINE_SIZE
83 source "arch/$(HEADER_ARCH)/um/Kconfig"
85 config MAY_HAVE_RUNTIME_DEPS
89 bool "Force a static link"
90 depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS
92 This option gives you the ability to force a static link of UML.
93 Normally, UML is linked as a shared binary. This is inconvenient for
94 use in a chroot jail. So, if you intend to run UML inside a chroot,
95 you probably want to say Y here.
96 Additionally, this option enables using higher memory spaces (up to
99 NOTE: This option is incompatible with some networking features which
100 depend on features that require being dynamically loaded (like NSS).
102 config LD_SCRIPT_STATIC
105 depends on STATIC_LINK
110 depends on !LD_SCRIPT_STATIC
111 select MODULE_REL_CRCS if MODVERSIONS
113 config LD_SCRIPT_DYN_RPATH
114 bool "set rpath in the binary" if EXPERT
116 depends on LD_SCRIPT_DYN
118 Add /lib (and /lib64 for 64-bit) to the linux binary's rpath
121 You may need to turn this off if compiling for nix systems
122 that have their libraries in random /nix directories and
123 might otherwise unexpected use libraries from /lib or /lib64
124 instead of the desired ones.
127 tristate "Host filesystem"
129 While the User-Mode Linux port uses its own root file system for
130 booting and normal file access, this module lets the UML user
131 access files stored on the host. It does not require any
132 network connection between the Host and UML. An example use of
135 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
137 where /tmp/fromhost is an empty directory inside UML and
138 /tmp/umlshare is a directory on the host with files the UML user
141 For more information, see
142 <http://user-mode-linux.sourceforge.net/hostfs.html>.
144 If you'd like to be able to work with files stored on the host,
145 say Y or M here; otherwise say N.
148 bool "Management console"
152 The user mode linux management console is a low-level interface to
153 the kernel, somewhat like the i386 SysRq interface. Since there is
154 a full-blown operating system running under every user mode linux
155 instance, there is much greater flexibility possible than with the
158 If you answer 'Y' to this option, to use this feature, you need the
159 mconsole client (called uml_mconsole) which is present in CVS in
160 2.4.5-9um and later (path /tools/mconsole), and is also in the
161 distribution RPM package in 2.4.6 and later.
163 It is safe to say 'Y' here.
166 bool "Magic SysRq key"
169 If you say Y here, you will have some control over the system even
170 if the system crashes for example during kernel debugging (e.g., you
171 will be able to flush the buffer cache to disk, reboot the system
172 immediately or dump some status information). A key for each of the
173 possible requests is provided.
175 This is the feature normally accomplished by pressing a key
176 while holding SysRq (Alt+PrintScreen).
178 On UML, this is accomplished by sending a "sysrq" command with
179 mconsole, followed by the letter for the requested command.
181 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y
182 unless you really know what this hack does.
184 config KERNEL_STACK_ORDER
185 int "Kernel stack size order"
190 This option determines the size of UML kernel stacks. They will
191 be 1 << order pages. The default is OK unless you're running Valgrind
192 on UML, in which case, set this to 3.
193 It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on
194 older (pre-2017) CPUs. It is not recommended on newer CPUs due to the
195 increase in the size of the state which needs to be saved when handling
199 tristate "iomem emulation driver"
201 This driver allows a host file to be used as emulated IO memory inside
204 config PGTABLE_LEVELS
206 default 3 if 3_LEVEL_PGTABLES
209 config UML_TIME_TRAVEL_SUPPORT
211 prompt "Support time-travel mode (e.g. for test execution)"
212 # inf-cpu mode is incompatible with the benchmarking
213 depends on !RAID6_PQ_BENCHMARK
216 Enable this option to support time travel inside the UML instance.
218 After enabling this option, two modes are accessible at runtime
219 (selected by the kernel command line), see the kernel's command-
220 line help for more details.
222 It is safe to say Y, but you probably don't need this.
226 source "arch/um/drivers/Kconfig"
228 config ARCH_SUSPEND_POSSIBLE
231 source "kernel/power/Kconfig"