1# SPDX-License-Identifier: GPL-2.0 2 3menu "UML-specific options" 4 5config 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_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 27 28config MMU 29 bool 30 default y 31 32config UML_DMA_EMULATION 33 bool 34 35config NO_IOMEM 36 bool "disable IOMEM" if EXPERT 37 depends on !INDIRECT_IOMEM 38 default y 39 40config 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 47config NO_IOPORT_MAP 48 def_bool y 49 50config ISA 51 bool 52 53config SBUS 54 bool 55 56config LOCKDEP_SUPPORT 57 bool 58 default y 59 60config STACKTRACE_SUPPORT 61 bool 62 default y 63 select STACKTRACE 64 65config GENERIC_CALIBRATE_DELAY 66 bool 67 default y 68 69config HZ 70 int 71 default 100 72 73config NR_CPUS 74 int 75 range 1 1 76 default 1 77 78config ARCH_HAS_CACHE_LINE_SIZE 79 def_bool y 80 81source "arch/$(HEADER_ARCH)/um/Kconfig" 82 83config MAY_HAVE_RUNTIME_DEPS 84 bool 85 86config 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 100config LD_SCRIPT_STATIC 101 bool 102 default y 103 depends on STATIC_LINK 104 105config LD_SCRIPT_DYN 106 bool 107 default y 108 depends on !LD_SCRIPT_STATIC 109 110config LD_SCRIPT_DYN_RPATH 111 bool "set rpath in the binary" if EXPERT 112 default y 113 depends on LD_SCRIPT_DYN 114 help 115 Add /lib (and /lib64 for 64-bit) to the linux binary's rpath 116 explicitly. 117 118 You may need to turn this off if compiling for nix systems 119 that have their libraries in random /nix directories and 120 might otherwise unexpected use libraries from /lib or /lib64 121 instead of the desired ones. 122 123config HOSTFS 124 tristate "Host filesystem" 125 help 126 While the User-Mode Linux port uses its own root file system for 127 booting and normal file access, this module lets the UML user 128 access files stored on the host. It does not require any 129 network connection between the Host and UML. An example use of 130 this might be: 131 132 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare 133 134 where /tmp/fromhost is an empty directory inside UML and 135 /tmp/umlshare is a directory on the host with files the UML user 136 wishes to access. 137 138 For more information, see 139 <http://user-mode-linux.sourceforge.net/hostfs.html>. 140 141 If you'd like to be able to work with files stored on the host, 142 say Y or M here; otherwise say N. 143 144config MCONSOLE 145 bool "Management console" 146 depends on PROC_FS 147 default y 148 help 149 The user mode linux management console is a low-level interface to 150 the kernel, somewhat like the i386 SysRq interface. Since there is 151 a full-blown operating system running under every user mode linux 152 instance, there is much greater flexibility possible than with the 153 SysRq mechanism. 154 155 If you answer 'Y' to this option, to use this feature, you need the 156 mconsole client (called uml_mconsole) which is present in CVS in 157 2.4.5-9um and later (path /tools/mconsole), and is also in the 158 distribution RPM package in 2.4.6 and later. 159 160 It is safe to say 'Y' here. 161 162config MAGIC_SYSRQ 163 bool "Magic SysRq key" 164 depends on MCONSOLE 165 help 166 If you say Y here, you will have some control over the system even 167 if the system crashes for example during kernel debugging (e.g., you 168 will be able to flush the buffer cache to disk, reboot the system 169 immediately or dump some status information). A key for each of the 170 possible requests is provided. 171 172 This is the feature normally accomplished by pressing a key 173 while holding SysRq (Alt+PrintScreen). 174 175 On UML, this is accomplished by sending a "sysrq" command with 176 mconsole, followed by the letter for the requested command. 177 178 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y 179 unless you really know what this hack does. 180 181config KERNEL_STACK_ORDER 182 int "Kernel stack size order" 183 default 2 if 64BIT 184 range 2 10 if 64BIT 185 default 1 if !64BIT 186 help 187 This option determines the size of UML kernel stacks. They will 188 be 1 << order pages. The default is OK unless you're running Valgrind 189 on UML, in which case, set this to 3. 190 It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on 191 older (pre-2017) CPUs. It is not recommended on newer CPUs due to the 192 increase in the size of the state which needs to be saved when handling 193 signals. 194 195config MMAPPER 196 tristate "iomem emulation driver" 197 help 198 This driver allows a host file to be used as emulated IO memory inside 199 UML. 200 201config PGTABLE_LEVELS 202 int 203 default 3 if 3_LEVEL_PGTABLES 204 default 2 205 206config UML_TIME_TRAVEL_SUPPORT 207 bool 208 prompt "Support time-travel mode (e.g. for test execution)" 209 # inf-cpu mode is incompatible with the benchmarking 210 depends on !RAID6_PQ_BENCHMARK 211 depends on !SMP 212 help 213 Enable this option to support time travel inside the UML instance. 214 215 After enabling this option, two modes are accessible at runtime 216 (selected by the kernel command line), see the kernel's command- 217 line help for more details. 218 219 It is safe to say Y, but you probably don't need this. 220 221endmenu 222 223source "arch/um/drivers/Kconfig" 224 225config ARCH_SUSPEND_POSSIBLE 226 def_bool y 227 228source "kernel/power/Kconfig" 229