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_DEBUG_KMEMLEAK
18 select HAVE_DEBUG_BUGVERBOSE
19 select NO_DMA if !UML_DMA_EMULATION
20 select OF_EARLY_FLATTREE if OF
21 select GENERIC_IRQ_SHOW
22 select GENERIC_CPU_DEVICES
23 select HAVE_GCC_PLUGINS
24 select TRACE_IRQFLAGS_SUPPORT
25 select TTY # Needed for line.c
26 select HAVE_ARCH_VMAP_STACK
32 config UML_DMA_EMULATION
36 bool "disable IOMEM" if EXPERT
37 depends on !INDIRECT_IOMEM
40 config UML_IOMEM_EMULATION
43 select GENERIC_PCI_IOMAP
45 select NO_GENERIC_PCI_IOPORT_MAP
56 config LOCKDEP_SUPPORT
60 config STACKTRACE_SUPPORT
65 config GENERIC_CALIBRATE_DELAY
78 config ARCH_HAS_CACHE_LINE_SIZE
81 source "arch/$(HEADER_ARCH)/um/Kconfig"
83 config MAY_HAVE_RUNTIME_DEPS
87 bool "Force a static link"
88 depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS
90 This option gives you the ability to force a static link of UML.
91 Normally, UML is linked as a shared binary. This is inconvenient for
92 use in a chroot jail. So, if you intend to run UML inside a chroot,
93 you probably want to say Y here.
94 Additionally, this option enables using higher memory spaces (up to
97 NOTE: This option is incompatible with some networking features which
98 depend on features that require being dynamically loaded (like NSS).
100 config LD_SCRIPT_STATIC
103 depends on STATIC_LINK
108 depends on !LD_SCRIPT_STATIC
109 select MODULE_REL_CRCS if MODVERSIONS
111 config LD_SCRIPT_DYN_RPATH
112 bool "set rpath in the binary" if EXPERT
114 depends on LD_SCRIPT_DYN
116 Add /lib (and /lib64 for 64-bit) to the linux binary's rpath
119 You may need to turn this off if compiling for nix systems
120 that have their libraries in random /nix directories and
121 might otherwise unexpected use libraries from /lib or /lib64
122 instead of the desired ones.
125 tristate "Host filesystem"
127 While the User-Mode Linux port uses its own root file system for
128 booting and normal file access, this module lets the UML user
129 access files stored on the host. It does not require any
130 network connection between the Host and UML. An example use of
133 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
135 where /tmp/fromhost is an empty directory inside UML and
136 /tmp/umlshare is a directory on the host with files the UML user
139 For more information, see
140 <http://user-mode-linux.sourceforge.net/hostfs.html>.
142 If you'd like to be able to work with files stored on the host,
143 say Y or M here; otherwise say N.
146 bool "Management console"
150 The user mode linux management console is a low-level interface to
151 the kernel, somewhat like the i386 SysRq interface. Since there is
152 a full-blown operating system running under every user mode linux
153 instance, there is much greater flexibility possible than with the
156 If you answer 'Y' to this option, to use this feature, you need the
157 mconsole client (called uml_mconsole) which is present in CVS in
158 2.4.5-9um and later (path /tools/mconsole), and is also in the
159 distribution RPM package in 2.4.6 and later.
161 It is safe to say 'Y' here.
164 bool "Magic SysRq key"
167 If you say Y here, you will have some control over the system even
168 if the system crashes for example during kernel debugging (e.g., you
169 will be able to flush the buffer cache to disk, reboot the system
170 immediately or dump some status information). A key for each of the
171 possible requests is provided.
173 This is the feature normally accomplished by pressing a key
174 while holding SysRq (Alt+PrintScreen).
176 On UML, this is accomplished by sending a "sysrq" command with
177 mconsole, followed by the letter for the requested command.
179 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y
180 unless you really know what this hack does.
182 config KERNEL_STACK_ORDER
183 int "Kernel stack size order"
188 This option determines the size of UML kernel stacks. They will
189 be 1 << order pages. The default is OK unless you're running Valgrind
190 on UML, in which case, set this to 3.
191 It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on
192 older (pre-2017) CPUs. It is not recommended on newer CPUs due to the
193 increase in the size of the state which needs to be saved when handling
197 tristate "iomem emulation driver"
199 This driver allows a host file to be used as emulated IO memory inside
202 config PGTABLE_LEVELS
204 default 3 if 3_LEVEL_PGTABLES
207 config UML_TIME_TRAVEL_SUPPORT
209 prompt "Support time-travel mode (e.g. for test execution)"
210 # inf-cpu mode is incompatible with the benchmarking
211 depends on !RAID6_PQ_BENCHMARK
214 Enable this option to support time travel inside the UML instance.
216 After enabling this option, two modes are accessible at runtime
217 (selected by the kernel command line), see the kernel's command-
218 line help for more details.
220 It is safe to say Y, but you probably don't need this.
224 source "arch/um/drivers/Kconfig"
226 config ARCH_SUSPEND_POSSIBLE
229 source "kernel/power/Kconfig"