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_CPU_FINALIZE_INIT 10 select ARCH_HAS_KCOV 11 select ARCH_HAS_STRNCPY_FROM_USER 12 select ARCH_HAS_STRNLEN_USER 13 select ARCH_NO_PREEMPT 14 select HAVE_ARCH_AUDITSYSCALL 15 select HAVE_ARCH_KASAN if X86_64 16 select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN 17 select HAVE_ARCH_SECCOMP_FILTER 18 select HAVE_ASM_MODVERSIONS 19 select HAVE_UID16 20 select HAVE_FUTEX_CMPXCHG if FUTEX 21 select HAVE_DEBUG_KMEMLEAK 22 select HAVE_DEBUG_BUGVERBOSE 23 select NO_DMA if !UML_DMA_EMULATION 24 select GENERIC_IRQ_SHOW 25 select GENERIC_CPU_DEVICES 26 select HAVE_GCC_PLUGINS 27 select SET_FS 28 select TRACE_IRQFLAGS_SUPPORT 29 select TTY # Needed for line.c 30 select HAVE_ARCH_VMAP_STACK 31 32config MMU 33 bool 34 default y 35 36config UML_DMA_EMULATION 37 bool 38 39config NO_IOMEM 40 bool "disable IOMEM" if EXPERT 41 depends on !INDIRECT_IOMEM 42 default y 43 44config UML_IOMEM_EMULATION 45 bool 46 select INDIRECT_IOMEM 47 select GENERIC_PCI_IOMAP 48 select GENERIC_IOMAP 49 select NO_GENERIC_PCI_IOPORT_MAP 50 51config NO_IOPORT_MAP 52 def_bool y 53 54config ISA 55 bool 56 57config SBUS 58 bool 59 60config LOCKDEP_SUPPORT 61 bool 62 default y 63 64config STACKTRACE_SUPPORT 65 bool 66 default y 67 select STACKTRACE 68 69config GENERIC_CALIBRATE_DELAY 70 bool 71 default y 72 73config HZ 74 int 75 default 100 76 77config NR_CPUS 78 int 79 range 1 1 80 default 1 81 82config ARCH_HAS_CACHE_LINE_SIZE 83 def_bool y 84 85source "arch/$(HEADER_ARCH)/um/Kconfig" 86 87config MAY_HAVE_RUNTIME_DEPS 88 bool 89 90config STATIC_LINK 91 bool "Force a static link" 92 depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS 93 help 94 This option gives you the ability to force a static link of UML. 95 Normally, UML is linked as a shared binary. This is inconvenient for 96 use in a chroot jail. So, if you intend to run UML inside a chroot, 97 you probably want to say Y here. 98 Additionally, this option enables using higher memory spaces (up to 99 2.75G) for UML. 100 101 NOTE: This option is incompatible with some networking features which 102 depend on features that require being dynamically loaded (like NSS). 103 104config LD_SCRIPT_STATIC 105 bool 106 default y 107 depends on STATIC_LINK 108 109config LD_SCRIPT_DYN 110 bool 111 default y 112 depends on !LD_SCRIPT_STATIC 113 select MODULE_REL_CRCS if MODVERSIONS 114 115config LD_SCRIPT_DYN_RPATH 116 bool "set rpath in the binary" if EXPERT 117 default y 118 depends on LD_SCRIPT_DYN 119 help 120 Add /lib (and /lib64 for 64-bit) to the linux binary's rpath 121 explicitly. 122 123 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. 127 128config HOSTFS 129 tristate "Host filesystem" 130 help 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 135 this might be: 136 137 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare 138 139 where /tmp/fromhost is an empty directory inside UML and 140 /tmp/umlshare is a directory on the host with files the UML user 141 wishes to access. 142 143 For more information, see 144 <http://user-mode-linux.sourceforge.net/hostfs.html>. 145 146 If you'd like to be able to work with files stored on the host, 147 say Y or M here; otherwise say N. 148 149config MCONSOLE 150 bool "Management console" 151 depends on PROC_FS 152 default y 153 help 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 158 SysRq mechanism. 159 160 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. 164 165 It is safe to say 'Y' here. 166 167config MAGIC_SYSRQ 168 bool "Magic SysRq key" 169 depends on MCONSOLE 170 help 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. 176 177 This is the feature normally accomplished by pressing a key 178 while holding SysRq (Alt+PrintScreen). 179 180 On UML, this is accomplished by sending a "sysrq" command with 181 mconsole, followed by the letter for the requested command. 182 183 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y 184 unless you really know what this hack does. 185 186config KERNEL_STACK_ORDER 187 int "Kernel stack size order" 188 default 2 if 64BIT 189 range 2 10 if 64BIT 190 default 1 if !64BIT 191 help 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 198 signals. 199 200config MMAPPER 201 tristate "iomem emulation driver" 202 help 203 This driver allows a host file to be used as emulated IO memory inside 204 UML. 205 206config PGTABLE_LEVELS 207 int 208 default 3 if 3_LEVEL_PGTABLES 209 default 2 210 211config UML_TIME_TRAVEL_SUPPORT 212 bool 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 216 depends on !SMP 217 help 218 Enable this option to support time travel inside the UML instance. 219 220 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. 223 224 It is safe to say Y, but you probably don't need this. 225 226config KASAN_SHADOW_OFFSET 227 hex 228 depends on KASAN 229 default 0x100000000000 230 help 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. 238 239endmenu 240 241source "arch/um/drivers/Kconfig" 242 243config ARCH_SUSPEND_POSSIBLE 244 def_bool y 245 246source "kernel/power/Kconfig" 247