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_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 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 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 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 114config LD_SCRIPT_DYN_RPATH 115 bool "set rpath in the binary" if EXPERT 116 default y 117 depends on LD_SCRIPT_DYN 118 help 119 Add /lib (and /lib64 for 64-bit) to the linux binary's rpath 120 explicitly. 121 122 You may need to turn this off if compiling for nix systems 123 that have their libraries in random /nix directories and 124 might otherwise unexpected use libraries from /lib or /lib64 125 instead of the desired ones. 126 127config HOSTFS 128 tristate "Host filesystem" 129 help 130 While the User-Mode Linux port uses its own root file system for 131 booting and normal file access, this module lets the UML user 132 access files stored on the host. It does not require any 133 network connection between the Host and UML. An example use of 134 this might be: 135 136 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare 137 138 where /tmp/fromhost is an empty directory inside UML and 139 /tmp/umlshare is a directory on the host with files the UML user 140 wishes to access. 141 142 For more information, see 143 <http://user-mode-linux.sourceforge.net/hostfs.html>. 144 145 If you'd like to be able to work with files stored on the host, 146 say Y or M here; otherwise say N. 147 148config MCONSOLE 149 bool "Management console" 150 depends on PROC_FS 151 default y 152 help 153 The user mode linux management console is a low-level interface to 154 the kernel, somewhat like the i386 SysRq interface. Since there is 155 a full-blown operating system running under every user mode linux 156 instance, there is much greater flexibility possible than with the 157 SysRq mechanism. 158 159 If you answer 'Y' to this option, to use this feature, you need the 160 mconsole client (called uml_mconsole) which is present in CVS in 161 2.4.5-9um and later (path /tools/mconsole), and is also in the 162 distribution RPM package in 2.4.6 and later. 163 164 It is safe to say 'Y' here. 165 166config MAGIC_SYSRQ 167 bool "Magic SysRq key" 168 depends on MCONSOLE 169 help 170 If you say Y here, you will have some control over the system even 171 if the system crashes for example during kernel debugging (e.g., you 172 will be able to flush the buffer cache to disk, reboot the system 173 immediately or dump some status information). A key for each of the 174 possible requests is provided. 175 176 This is the feature normally accomplished by pressing a key 177 while holding SysRq (Alt+PrintScreen). 178 179 On UML, this is accomplished by sending a "sysrq" command with 180 mconsole, followed by the letter for the requested command. 181 182 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y 183 unless you really know what this hack does. 184 185config KERNEL_STACK_ORDER 186 int "Kernel stack size order" 187 default 2 if 64BIT 188 range 2 10 if 64BIT 189 default 1 if !64BIT 190 help 191 This option determines the size of UML kernel stacks. They will 192 be 1 << order pages. The default is OK unless you're running Valgrind 193 on UML, in which case, set this to 3. 194 It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on 195 older (pre-2017) CPUs. It is not recommended on newer CPUs due to the 196 increase in the size of the state which needs to be saved when handling 197 signals. 198 199config MMAPPER 200 tristate "iomem emulation driver" 201 help 202 This driver allows a host file to be used as emulated IO memory inside 203 UML. 204 205config PGTABLE_LEVELS 206 int 207 default 3 if 3_LEVEL_PGTABLES 208 default 2 209 210config UML_TIME_TRAVEL_SUPPORT 211 bool 212 prompt "Support time-travel mode (e.g. for test execution)" 213 # inf-cpu mode is incompatible with the benchmarking 214 depends on !RAID6_PQ_BENCHMARK 215 depends on !SMP 216 help 217 Enable this option to support time travel inside the UML instance. 218 219 After enabling this option, two modes are accessible at runtime 220 (selected by the kernel command line), see the kernel's command- 221 line help for more details. 222 223 It is safe to say Y, but you probably don't need this. 224 225config KASAN_SHADOW_OFFSET 226 hex 227 depends on KASAN 228 default 0x100000000000 229 help 230 This is the offset at which the ~16TB of shadow memory is 231 mapped and used by KASAN for memory debugging. This can be any 232 address that has at least KASAN_SHADOW_SIZE (total address space divided 233 by 8) amount of space so that the KASAN shadow memory does not conflict 234 with anything. The default is 0x100000000000, which works even if mem is 235 set to a large value. On low-memory systems, try 0x7fff8000, as it fits 236 into the immediate of most instructions, improving performance. 237 238endmenu 239 240source "arch/um/drivers/Kconfig" 241 242config ARCH_SUSPEND_POSSIBLE 243 def_bool y 244 245source "kernel/power/Kconfig" 246