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