arch/um/Kconfig

   1 # SPDX-License-Identifier: GPL-2.0
   2
   3 menu "UML-specific options"
   4
   5 config UML
   6         bool
   7         default y
   8         select ARCH_EPHEMERAL_INODES
   9         select ARCH_HAS_KCOV
  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
  16         select HAVE_UID16
  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
  24         select SET_FS
  25         select TRACE_IRQFLAGS_SUPPORT
  26         select TTY # Needed for line.c
  27
  28 config MMU
  29         bool
  30         default y
  31
  32 config UML_DMA_EMULATION
  33         bool
  34
  35 config NO_IOMEM
  36         bool "disable IOMEM" if EXPERT
  37         depends on !INDIRECT_IOMEM
  38         default y
  39
  40 config UML_IOMEM_EMULATION
  41         bool
  42         select INDIRECT_IOMEM
  43         select GENERIC_PCI_IOMAP
  44         select GENERIC_IOMAP
  45         select NO_GENERIC_PCI_IOPORT_MAP
  46
  47 config NO_IOPORT_MAP
  48         def_bool y
  49
  50 config ISA
  51         bool
  52
  53 config SBUS
  54         bool
  55
  56 config LOCKDEP_SUPPORT
  57         bool
  58         default y
  59
  60 config STACKTRACE_SUPPORT
  61         bool
  62         default y
  63         select STACKTRACE
  64
  65 config GENERIC_CALIBRATE_DELAY
  66         bool
  67         default y
  68
  69 config HZ
  70         int
  71         default 100
  72
  73 config NR_CPUS
  74         int
  75         range 1 1
  76         default 1
  77
  78 config ARCH_HAS_CACHE_LINE_SIZE
  79         def_bool y
  80
  81 source "arch/$(HEADER_ARCH)/um/Kconfig"
  82
  83 config MAY_HAVE_RUNTIME_DEPS
  84         bool
  85
  86 config STATIC_LINK
  87         bool "Force a static link"
  88         depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS
  89         help
  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
  95           2.75G) for UML.
  96
  97           NOTE: This option is incompatible with some networking features which
  98           depend on features that require being dynamically loaded (like NSS).
  99
 100 config LD_SCRIPT_STATIC
 101         bool
 102         default y
 103         depends on STATIC_LINK
 104
 105 config LD_SCRIPT_DYN
 106         bool
 107         default y
 108         depends on !LD_SCRIPT_STATIC
 109         select MODULE_REL_CRCS if MODVERSIONS
 110
 111 config LD_SCRIPT_DYN_RPATH
 112         bool "set rpath in the binary" if EXPERT
 113         default y
 114         depends on LD_SCRIPT_DYN
 115         help
 116           Add /lib (and /lib64 for 64-bit) to the linux binary's rpath
 117           explicitly.
 118
 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.
 123
 124 config HOSTFS
 125         tristate "Host filesystem"
 126         help
 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
 131           this might be:
 132
 133           mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
 134
 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
 137           wishes to access.
 138
 139           For more information, see
 140           <http://user-mode-linux.sourceforge.net/hostfs.html>.
 141
 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.
 144
 145 config MCONSOLE
 146         bool "Management console"
 147         depends on PROC_FS
 148         default y
 149         help
 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
 154           SysRq mechanism.
 155
 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.
 160
 161           It is safe to say 'Y' here.
 162
 163 config MAGIC_SYSRQ
 164         bool "Magic SysRq key"
 165         depends on MCONSOLE
 166         help
 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.
 172
 173           This is the feature normally accomplished by pressing a key
 174           while holding SysRq (Alt+PrintScreen).
 175
 176           On UML, this is accomplished by sending a "sysrq" command with
 177           mconsole, followed by the letter for the requested command.
 178
 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.
 181
 182 config KERNEL_STACK_ORDER
 183         int "Kernel stack size order"
 184         default 2 if 64BIT
 185         range 2 10 if 64BIT
 186         default 1 if !64BIT
 187         help
 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
 194           signals.
 195
 196 config MMAPPER
 197         tristate "iomem emulation driver"
 198         help
 199           This driver allows a host file to be used as emulated IO memory inside
 200           UML.
 201
 202 config PGTABLE_LEVELS
 203         int
 204         default 3 if 3_LEVEL_PGTABLES
 205         default 2
 206
 207 config UML_TIME_TRAVEL_SUPPORT
 208         bool
 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
 212         depends on !SMP
 213         help
 214           Enable this option to support time travel inside the UML instance.
 215
 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.
 219
 220           It is safe to say Y, but you probably don't need this.
 221
 222 endmenu
 223
 224 source "arch/um/drivers/Kconfig"
 225
 226 config ARCH_SUSPEND_POSSIBLE
 227         def_bool y
 228
 229 source "kernel/power/Kconfig"