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
29 config UML_DMA_EMULATION
33 bool "disable IOMEM" if EXPERT
34 depends on !INDIRECT_IOMEM
37 config UML_IOMEM_EMULATION
40 select GENERIC_PCI_IOMAP
42 select NO_GENERIC_PCI_IOPORT_MAP
53 config TRACE_IRQFLAGS_SUPPORT
57 config LOCKDEP_SUPPORT
61 config STACKTRACE_SUPPORT
66 config GENERIC_CALIBRATE_DELAY
79 source "arch/$(HEADER_ARCH)/um/Kconfig"
81 config MAY_HAVE_RUNTIME_DEPS
85 bool "Force a static link"
86 depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS
88 This option gives you the ability to force a static link of UML.
89 Normally, UML is linked as a shared binary. This is inconvenient for
90 use in a chroot jail. So, if you intend to run UML inside a chroot,
91 you probably want to say Y here.
92 Additionally, this option enables using higher memory spaces (up to
95 NOTE: This option is incompatible with some networking features which
96 depend on features that require being dynamically loaded (like NSS).
98 config LD_SCRIPT_STATIC
101 depends on STATIC_LINK
106 depends on !LD_SCRIPT_STATIC
107 select MODULE_REL_CRCS if MODVERSIONS
110 tristate "Host filesystem"
112 While the User-Mode Linux port uses its own root file system for
113 booting and normal file access, this module lets the UML user
114 access files stored on the host. It does not require any
115 network connection between the Host and UML. An example use of
118 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
120 where /tmp/fromhost is an empty directory inside UML and
121 /tmp/umlshare is a directory on the host with files the UML user
124 For more information, see
125 <http://user-mode-linux.sourceforge.net/hostfs.html>.
127 If you'd like to be able to work with files stored on the host,
128 say Y or M here; otherwise say N.
131 bool "Management console"
135 The user mode linux management console is a low-level interface to
136 the kernel, somewhat like the i386 SysRq interface. Since there is
137 a full-blown operating system running under every user mode linux
138 instance, there is much greater flexibility possible than with the
141 If you answer 'Y' to this option, to use this feature, you need the
142 mconsole client (called uml_mconsole) which is present in CVS in
143 2.4.5-9um and later (path /tools/mconsole), and is also in the
144 distribution RPM package in 2.4.6 and later.
146 It is safe to say 'Y' here.
149 bool "Magic SysRq key"
152 If you say Y here, you will have some control over the system even
153 if the system crashes for example during kernel debugging (e.g., you
154 will be able to flush the buffer cache to disk, reboot the system
155 immediately or dump some status information). A key for each of the
156 possible requests is provided.
158 This is the feature normally accomplished by pressing a key
159 while holding SysRq (Alt+PrintScreen).
161 On UML, this is accomplished by sending a "sysrq" command with
162 mconsole, followed by the letter for the requested command.
164 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y
165 unless you really know what this hack does.
167 config KERNEL_STACK_ORDER
168 int "Kernel stack size order"
173 This option determines the size of UML kernel stacks. They will
174 be 1 << order pages. The default is OK unless you're running Valgrind
175 on UML, in which case, set this to 3.
176 It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on
177 older (pre-2017) CPUs. It is not recommended on newer CPUs due to the
178 increase in the size of the state which needs to be saved when handling
182 tristate "iomem emulation driver"
184 This driver allows a host file to be used as emulated IO memory inside
187 config PGTABLE_LEVELS
189 default 3 if 3_LEVEL_PGTABLES
192 config UML_TIME_TRAVEL_SUPPORT
194 prompt "Support time-travel mode (e.g. for test execution)"
195 # inf-cpu mode is incompatible with the benchmarking
196 depends on !RAID6_PQ_BENCHMARK
199 Enable this option to support time travel inside the UML instance.
201 After enabling this option, two modes are accessible at runtime
202 (selected by the kernel command line), see the kernel's command-
203 line help for more details.
205 It is safe to say Y, but you probably don't need this.
209 source "arch/um/drivers/Kconfig"
211 config ARCH_SUSPEND_POSSIBLE
214 source "kernel/power/Kconfig"