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