1# SPDX-License-Identifier: GPL-2.0 2 3menu "UML-specific options" 4 5config UML 6 bool 7 default y 8 select ARCH_HAS_CPU_FINALIZE_INIT 9 select ARCH_HAS_FORTIFY_SOURCE 10 select ARCH_HAS_GCOV_PROFILE_ALL 11 select ARCH_HAS_KCOV 12 select ARCH_HAS_STRNCPY_FROM_USER 13 select ARCH_HAS_STRNLEN_USER 14 select ARCH_NO_PREEMPT_DYNAMIC 15 select HAVE_ARCH_AUDITSYSCALL 16 select HAVE_ARCH_KASAN if X86_64 17 select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN 18 select HAVE_ARCH_SECCOMP_FILTER 19 select HAVE_ASM_MODVERSIONS 20 select HAVE_UID16 21 select HAVE_DEBUG_KMEMLEAK 22 select HAVE_DEBUG_BUGVERBOSE 23 select HAVE_PAGE_SIZE_4KB 24 select NO_DMA if !UML_DMA_EMULATION 25 select OF_EARLY_FLATTREE if OF 26 select GENERIC_IRQ_SHOW 27 select GENERIC_CPU_DEVICES 28 select HAVE_GCC_PLUGINS 29 select ARCH_SUPPORTS_LTO_CLANG 30 select ARCH_SUPPORTS_LTO_CLANG_THIN 31 select TRACE_IRQFLAGS_SUPPORT 32 select TTY # Needed for line.c 33 select HAVE_ARCH_VMAP_STACK 34 select HAVE_RUST 35 select ARCH_HAS_UBSAN 36 37config MMU 38 bool 39 default y 40 41config UML_DMA_EMULATION 42 bool 43 44config NO_IOMEM 45 bool "disable IOMEM" if EXPERT 46 depends on !INDIRECT_IOMEM 47 default y 48 49config UML_IOMEM_EMULATION 50 bool 51 select INDIRECT_IOMEM 52 select HAS_IOPORT 53 select GENERIC_PCI_IOMAP 54 select GENERIC_IOMAP 55 select NO_GENERIC_PCI_IOPORT_MAP 56 57config NO_IOPORT_MAP 58 def_bool !UML_IOMEM_EMULATION 59 60config ISA 61 bool 62 63config SBUS 64 bool 65 66config LOCKDEP_SUPPORT 67 bool 68 default y 69 70config STACKTRACE_SUPPORT 71 bool 72 default y 73 select STACKTRACE 74 75config GENERIC_CALIBRATE_DELAY 76 bool 77 default y 78 79config HZ 80 int 81 default 100 82 83config NR_CPUS 84 int 85 range 1 1 86 default 1 87 88config ARCH_HAS_CACHE_LINE_SIZE 89 def_bool y 90 91source "arch/$(HEADER_ARCH)/um/Kconfig" 92 93config MAY_HAVE_RUNTIME_DEPS 94 bool 95 96config STATIC_LINK 97 bool "Force a static link" 98 depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS 99 help 100 This option gives you the ability to force a static link of UML. 101 Normally, UML is linked as a shared binary. This is inconvenient for 102 use in a chroot jail. So, if you intend to run UML inside a chroot, 103 you probably want to say Y here. 104 Additionally, this option enables using higher memory spaces (up to 105 2.75G) for UML. 106 107 NOTE: This option is incompatible with some networking features which 108 depend on features that require being dynamically loaded (like NSS). 109 110config LD_SCRIPT_STATIC 111 bool 112 default y 113 depends on STATIC_LINK 114 115config LD_SCRIPT_DYN 116 bool 117 default y 118 depends on !LD_SCRIPT_STATIC 119 120config LD_SCRIPT_DYN_RPATH 121 bool "set rpath in the binary" if EXPERT 122 default y 123 depends on LD_SCRIPT_DYN 124 help 125 Add /lib (and /lib64 for 64-bit) to the linux binary's rpath 126 explicitly. 127 128 You may need to turn this off if compiling for nix systems 129 that have their libraries in random /nix directories and 130 might otherwise unexpected use libraries from /lib or /lib64 131 instead of the desired ones. 132 133config HOSTFS 134 tristate "Host filesystem" 135 help 136 While the User-Mode Linux port uses its own root file system for 137 booting and normal file access, this module lets the UML user 138 access files stored on the host. It does not require any 139 network connection between the Host and UML. An example use of 140 this might be: 141 142 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare 143 144 where /tmp/fromhost is an empty directory inside UML and 145 /tmp/umlshare is a directory on the host with files the UML user 146 wishes to access. 147 148 For more information, see 149 <http://user-mode-linux.sourceforge.net/hostfs.html>. 150 151 If you'd like to be able to work with files stored on the host, 152 say Y or M here; otherwise say N. 153 154config MCONSOLE 155 bool "Management console" 156 depends on PROC_FS 157 default y 158 help 159 The user mode linux management console is a low-level interface to 160 the kernel, somewhat like the i386 SysRq interface. Since there is 161 a full-blown operating system running under every user mode linux 162 instance, there is much greater flexibility possible than with the 163 SysRq mechanism. 164 165 If you answer 'Y' to this option, to use this feature, you need the 166 mconsole client (called uml_mconsole) which is present in CVS in 167 2.4.5-9um and later (path /tools/mconsole), and is also in the 168 distribution RPM package in 2.4.6 and later. 169 170 It is safe to say 'Y' here. 171 172config MAGIC_SYSRQ 173 bool "Magic SysRq key" 174 depends on MCONSOLE 175 help 176 If you say Y here, you will have some control over the system even 177 if the system crashes for example during kernel debugging (e.g., you 178 will be able to flush the buffer cache to disk, reboot the system 179 immediately or dump some status information). A key for each of the 180 possible requests is provided. 181 182 This is the feature normally accomplished by pressing a key 183 while holding SysRq (Alt+PrintScreen). 184 185 On UML, this is accomplished by sending a "sysrq" command with 186 mconsole, followed by the letter for the requested command. 187 188 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y 189 unless you really know what this hack does. 190 191config KERNEL_STACK_ORDER 192 int "Kernel stack size order" 193 default 2 if 64BIT 194 range 2 10 if 64BIT 195 default 1 if !64BIT 196 help 197 This option determines the size of UML kernel stacks. They will 198 be 1 << order pages. The default is OK unless you're running Valgrind 199 on UML, in which case, set this to 3. 200 It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on 201 older (pre-2017) CPUs. It is not recommended on newer CPUs due to the 202 increase in the size of the state which needs to be saved when handling 203 signals. 204 205config MMAPPER 206 tristate "iomem emulation driver" 207 help 208 This driver allows a host file to be used as emulated IO memory inside 209 UML. 210 211config PGTABLE_LEVELS 212 int 213 default 3 if 3_LEVEL_PGTABLES 214 default 2 215 216config UML_TIME_TRAVEL_SUPPORT 217 bool 218 prompt "Support time-travel mode (e.g. for test execution)" 219 # inf-cpu mode is incompatible with the benchmarking 220 depends on !RAID6_PQ_BENCHMARK 221 depends on !SMP 222 help 223 Enable this option to support time travel inside the UML instance. 224 225 After enabling this option, two modes are accessible at runtime 226 (selected by the kernel command line), see the kernel's command- 227 line help for more details. 228 229 It is safe to say Y, but you probably don't need this. 230 231config KASAN_SHADOW_OFFSET 232 hex 233 depends on KASAN 234 default 0x100000000000 235 help 236 This is the offset at which the ~16TB of shadow memory is 237 mapped and used by KASAN for memory debugging. This can be any 238 address that has at least KASAN_SHADOW_SIZE (total address space divided 239 by 8) amount of space so that the KASAN shadow memory does not conflict 240 with anything. The default is 0x100000000000, which works even if mem is 241 set to a large value. On low-memory systems, try 0x7fff8000, as it fits 242 into the immediate of most instructions, improving performance. 243 244endmenu 245 246source "arch/um/drivers/Kconfig" 247 248config ARCH_SUSPEND_POSSIBLE 249 def_bool y 250 251menu "Power management options" 252 253source "kernel/power/Kconfig" 254 255endmenu 256