1 # SPDX-License-Identifier: GPL-2.0
3 menu "UML-specific options"
8 select ARCH_EPHEMERAL_INODES
9 select ARCH_HAS_CPU_FINALIZE_INIT
10 select ARCH_HAS_FORTIFY_SOURCE
11 select ARCH_HAS_GCOV_PROFILE_ALL
13 select ARCH_HAS_STRNCPY_FROM_USER
14 select ARCH_HAS_STRNLEN_USER
15 select ARCH_NO_PREEMPT
16 select HAVE_ARCH_AUDITSYSCALL
17 select HAVE_ARCH_KASAN if X86_64
18 select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
19 select HAVE_ARCH_SECCOMP_FILTER
20 select HAVE_ASM_MODVERSIONS
22 select HAVE_DEBUG_KMEMLEAK
23 select HAVE_DEBUG_BUGVERBOSE
24 select NO_DMA if !UML_DMA_EMULATION
25 select OF_EARLY_FLATTREE if OF
26 select GENERIC_IRQ_SHOW
27 select GENERIC_CPU_DEVICES
28 select HAVE_GCC_PLUGINS
29 select TRACE_IRQFLAGS_SUPPORT
30 select TTY # Needed for line.c
31 select HAVE_ARCH_VMAP_STACK
37 config UML_DMA_EMULATION
41 bool "disable IOMEM" if EXPERT
42 depends on !INDIRECT_IOMEM
45 config UML_IOMEM_EMULATION
48 select GENERIC_PCI_IOMAP
50 select NO_GENERIC_PCI_IOPORT_MAP
61 config LOCKDEP_SUPPORT
65 config STACKTRACE_SUPPORT
70 config GENERIC_CALIBRATE_DELAY
83 config ARCH_HAS_CACHE_LINE_SIZE
86 source "arch/$(HEADER_ARCH)/um/Kconfig"
88 config MAY_HAVE_RUNTIME_DEPS
92 bool "Force a static link"
93 depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS
95 This option gives you the ability to force a static link of UML.
96 Normally, UML is linked as a shared binary. This is inconvenient for
97 use in a chroot jail. So, if you intend to run UML inside a chroot,
98 you probably want to say Y here.
99 Additionally, this option enables using higher memory spaces (up to
102 NOTE: This option is incompatible with some networking features which
103 depend on features that require being dynamically loaded (like NSS).
105 config LD_SCRIPT_STATIC
108 depends on STATIC_LINK
113 depends on !LD_SCRIPT_STATIC
115 config LD_SCRIPT_DYN_RPATH
116 bool "set rpath in the binary" if EXPERT
118 depends on LD_SCRIPT_DYN
120 Add /lib (and /lib64 for 64-bit) to the linux binary's rpath
123 You may need to turn this off if compiling for nix systems
124 that have their libraries in random /nix directories and
125 might otherwise unexpected use libraries from /lib or /lib64
126 instead of the desired ones.
129 tristate "Host filesystem"
131 While the User-Mode Linux port uses its own root file system for
132 booting and normal file access, this module lets the UML user
133 access files stored on the host. It does not require any
134 network connection between the Host and UML. An example use of
137 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
139 where /tmp/fromhost is an empty directory inside UML and
140 /tmp/umlshare is a directory on the host with files the UML user
143 For more information, see
144 <http://user-mode-linux.sourceforge.net/hostfs.html>.
146 If you'd like to be able to work with files stored on the host,
147 say Y or M here; otherwise say N.
150 bool "Management console"
154 The user mode linux management console is a low-level interface to
155 the kernel, somewhat like the i386 SysRq interface. Since there is
156 a full-blown operating system running under every user mode linux
157 instance, there is much greater flexibility possible than with the
160 If you answer 'Y' to this option, to use this feature, you need the
161 mconsole client (called uml_mconsole) which is present in CVS in
162 2.4.5-9um and later (path /tools/mconsole), and is also in the
163 distribution RPM package in 2.4.6 and later.
165 It is safe to say 'Y' here.
168 bool "Magic SysRq key"
171 If you say Y here, you will have some control over the system even
172 if the system crashes for example during kernel debugging (e.g., you
173 will be able to flush the buffer cache to disk, reboot the system
174 immediately or dump some status information). A key for each of the
175 possible requests is provided.
177 This is the feature normally accomplished by pressing a key
178 while holding SysRq (Alt+PrintScreen).
180 On UML, this is accomplished by sending a "sysrq" command with
181 mconsole, followed by the letter for the requested command.
183 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y
184 unless you really know what this hack does.
186 config KERNEL_STACK_ORDER
187 int "Kernel stack size order"
192 This option determines the size of UML kernel stacks. They will
193 be 1 << order pages. The default is OK unless you're running Valgrind
194 on UML, in which case, set this to 3.
195 It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on
196 older (pre-2017) CPUs. It is not recommended on newer CPUs due to the
197 increase in the size of the state which needs to be saved when handling
201 tristate "iomem emulation driver"
203 This driver allows a host file to be used as emulated IO memory inside
206 config PGTABLE_LEVELS
208 default 3 if 3_LEVEL_PGTABLES
211 config UML_TIME_TRAVEL_SUPPORT
213 prompt "Support time-travel mode (e.g. for test execution)"
214 # inf-cpu mode is incompatible with the benchmarking
215 depends on !RAID6_PQ_BENCHMARK
218 Enable this option to support time travel inside the UML instance.
220 After enabling this option, two modes are accessible at runtime
221 (selected by the kernel command line), see the kernel's command-
222 line help for more details.
224 It is safe to say Y, but you probably don't need this.
226 config KASAN_SHADOW_OFFSET
229 default 0x100000000000
231 This is the offset at which the ~16TB of shadow memory is
232 mapped and used by KASAN for memory debugging. This can be any
233 address that has at least KASAN_SHADOW_SIZE (total address space divided
234 by 8) amount of space so that the KASAN shadow memory does not conflict
235 with anything. The default is 0x100000000000, which works even if mem is
236 set to a large value. On low-memory systems, try 0x7fff8000, as it fits
237 into the immediate of most instructions, improving performance.
241 source "arch/um/drivers/Kconfig"
243 config ARCH_SUSPEND_POSSIBLE
246 source "kernel/power/Kconfig"