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 TTY # Needed for line.c
  26
  27 config MMU
  28         bool
  29         default y
  30
  31 config UML_DMA_EMULATION
  32         bool
  33
  34 config NO_IOMEM
  35         bool "disable IOMEM" if EXPERT
  36         depends on !INDIRECT_IOMEM
  37         default y
  38
  39 config UML_IOMEM_EMULATION
  40         bool
  41         select INDIRECT_IOMEM
  42         select GENERIC_PCI_IOMAP
  43         select GENERIC_IOMAP
  44         select NO_GENERIC_PCI_IOPORT_MAP
  45
  46 config NO_IOPORT_MAP
  47         def_bool y
  48
  49 config ISA
  50         bool
  51
  52 config SBUS
  53         bool
  54
  55 config TRACE_IRQFLAGS_SUPPORT
  56         bool
  57         default y
  58
  59 config LOCKDEP_SUPPORT
  60         bool
  61         default y
  62
  63 config STACKTRACE_SUPPORT
  64         bool
  65         default y
  66         select STACKTRACE
  67
  68 config GENERIC_CALIBRATE_DELAY
  69         bool
  70         default y
  71
  72 config HZ
  73         int
  74         default 100
  75
  76 config NR_CPUS
  77         int
  78         range 1 1
  79         default 1
  80
  81 config ARCH_HAS_CACHE_LINE_SIZE
  82         def_bool y
  83
  84 source "arch/$(HEADER_ARCH)/um/Kconfig"
  85
  86 config MAY_HAVE_RUNTIME_DEPS
  87         bool
  88
  89 config STATIC_LINK
  90         bool "Force a static link"
  91         depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS
  92         help
  93           This option gives you the ability to force a static link of UML.
  94           Normally, UML is linked as a shared binary.  This is inconvenient for
  95           use in a chroot jail.  So, if you intend to run UML inside a chroot,
  96           you probably want to say Y here.
  97           Additionally, this option enables using higher memory spaces (up to
  98           2.75G) for UML.
  99
 100           NOTE: This option is incompatible with some networking features which
 101           depend on features that require being dynamically loaded (like NSS).
 102
 103 config LD_SCRIPT_STATIC
 104         bool
 105         default y
 106         depends on STATIC_LINK
 107
 108 config LD_SCRIPT_DYN
 109         bool
 110         default y
 111         depends on !LD_SCRIPT_STATIC
 112         select MODULE_REL_CRCS if MODVERSIONS
 113
 114 config LD_SCRIPT_DYN_RPATH
 115         bool "set rpath in the binary" if EXPERT
 116         default y
 117         depends on LD_SCRIPT_DYN
 118         help
 119           Add /lib (and /lib64 for 64-bit) to the linux binary's rpath
 120           explicitly.
 121
 122           You may need to turn this off if compiling for nix systems
 123           that have their libraries in random /nix directories and
 124           might otherwise unexpected use libraries from /lib or /lib64
 125           instead of the desired ones.
 126
 127 config HOSTFS
 128         tristate "Host filesystem"
 129         help
 130           While the User-Mode Linux port uses its own root file system for
 131           booting and normal file access, this module lets the UML user
 132           access files stored on the host.  It does not require any
 133           network connection between the Host and UML.  An example use of
 134           this might be:
 135
 136           mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
 137
 138           where /tmp/fromhost is an empty directory inside UML and
 139           /tmp/umlshare is a directory on the host with files the UML user
 140           wishes to access.
 141
 142           For more information, see
 143           <http://user-mode-linux.sourceforge.net/hostfs.html>.
 144
 145           If you'd like to be able to work with files stored on the host,
 146           say Y or M here; otherwise say N.
 147
 148 config MCONSOLE
 149         bool "Management console"
 150         depends on PROC_FS
 151         default y
 152         help
 153           The user mode linux management console is a low-level interface to
 154           the kernel, somewhat like the i386 SysRq interface.  Since there is
 155           a full-blown operating system running under every user mode linux
 156           instance, there is much greater flexibility possible than with the
 157           SysRq mechanism.
 158
 159           If you answer 'Y' to this option, to use this feature, you need the
 160           mconsole client (called uml_mconsole) which is present in CVS in
 161           2.4.5-9um and later (path /tools/mconsole), and is also in the
 162           distribution RPM package in 2.4.6 and later.
 163
 164           It is safe to say 'Y' here.
 165
 166 config MAGIC_SYSRQ
 167         bool "Magic SysRq key"
 168         depends on MCONSOLE
 169         help
 170           If you say Y here, you will have some control over the system even
 171           if the system crashes for example during kernel debugging (e.g., you
 172           will be able to flush the buffer cache to disk, reboot the system
 173           immediately or dump some status information). A key for each of the
 174           possible requests is provided.
 175
 176           This is the feature normally accomplished by pressing a key
 177           while holding SysRq (Alt+PrintScreen).
 178
 179           On UML, this is accomplished by sending a "sysrq" command with
 180           mconsole, followed by the letter for the requested command.
 181
 182           The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y
 183           unless you really know what this hack does.
 184
 185 config KERNEL_STACK_ORDER
 186         int "Kernel stack size order"
 187         default 2 if 64BIT
 188         range 2 10 if 64BIT
 189         default 1 if !64BIT
 190         help
 191           This option determines the size of UML kernel stacks.  They will
 192           be 1 << order pages.  The default is OK unless you're running Valgrind
 193           on UML, in which case, set this to 3.
 194           It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on
 195           older (pre-2017) CPUs. It is not recommended on newer CPUs due to the
 196           increase in the size of the state which needs to be saved when handling
 197           signals.
 198
 199 config MMAPPER
 200         tristate "iomem emulation driver"
 201         help
 202           This driver allows a host file to be used as emulated IO memory inside
 203           UML.
 204
 205 config PGTABLE_LEVELS
 206         int
 207         default 3 if 3_LEVEL_PGTABLES
 208         default 2
 209
 210 config UML_TIME_TRAVEL_SUPPORT
 211         bool
 212         prompt "Support time-travel mode (e.g. for test execution)"
 213         # inf-cpu mode is incompatible with the benchmarking
 214         depends on !RAID6_PQ_BENCHMARK
 215         depends on !SMP
 216         help
 217           Enable this option to support time travel inside the UML instance.
 218
 219           After enabling this option, two modes are accessible at runtime
 220           (selected by the kernel command line), see the kernel's command-
 221           line help for more details.
 222
 223           It is safe to say Y, but you probably don't need this.
 224
 225 endmenu
 226
 227 source "arch/um/drivers/Kconfig"
 228
 229 config ARCH_SUSPEND_POSSIBLE
 230         def_bool y
 231
 232 source "kernel/power/Kconfig"