1# SPDX-License-Identifier: GPL-2.0 2 3menu "UML-specific options" 4 5config UML 6 bool 7 default y 8 select ARCH_NEEDS_DEFER_KASAN if STATIC_LINK 9 select ARCH_WANTS_DYNAMIC_TASK_STRUCT 10 select ARCH_HAS_CACHE_LINE_SIZE 11 select ARCH_HAS_CPU_FINALIZE_INIT 12 select ARCH_HAS_FORTIFY_SOURCE 13 select ARCH_HAS_GCOV_PROFILE_ALL 14 select ARCH_HAS_KCOV 15 select ARCH_HAS_STRNCPY_FROM_USER 16 select ARCH_HAS_STRNLEN_USER 17 select ARCH_HAS_STRICT_KERNEL_RWX 18 select HAVE_ARCH_AUDITSYSCALL 19 select HAVE_ARCH_KASAN if X86_64 20 select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN 21 select HAVE_ARCH_SECCOMP_FILTER 22 select HAVE_ASM_MODVERSIONS 23 select HAVE_UID16 24 select HAVE_DEBUG_KMEMLEAK 25 select HAVE_DEBUG_BUGVERBOSE 26 select HAVE_PAGE_SIZE_4KB 27 select NO_DMA if !UML_DMA_EMULATION 28 select OF_EARLY_FLATTREE if OF 29 select GENERIC_IRQ_SHOW 30 select GENERIC_CPU_DEVICES 31 select HAVE_GCC_PLUGINS 32 select ARCH_SUPPORTS_LTO_CLANG 33 select ARCH_SUPPORTS_LTO_CLANG_THIN 34 select TRACE_IRQFLAGS_SUPPORT 35 select TTY # Needed for line.c 36 select HAVE_ARCH_VMAP_STACK 37 select HAVE_RUST 38 select ARCH_HAS_UBSAN 39 select HAVE_ARCH_TRACEHOOK 40 select HAVE_SYSCALL_TRACEPOINTS 41 select THREAD_INFO_IN_TASK 42 select SPARSE_IRQ 43 44config MMU 45 bool 46 default y 47 48config UML_DMA_EMULATION 49 bool 50 51config NO_IOMEM 52 bool "disable IOMEM" if EXPERT 53 depends on !INDIRECT_IOMEM 54 default y 55 56config UML_IOMEM_EMULATION 57 bool 58 select INDIRECT_IOMEM 59 select GENERIC_PCI_IOMAP 60 61config ISA 62 bool 63 64config SBUS 65 bool 66 67config LOCKDEP_SUPPORT 68 bool 69 default y 70 71config STACKTRACE_SUPPORT 72 bool 73 default y 74 select STACKTRACE 75 76config GENERIC_CALIBRATE_DELAY 77 bool 78 default y 79 80config HZ 81 int 82 default 100 83 84config NR_CPUS 85 int 86 range 1 1 87 default 1 88 89source "arch/$(HEADER_ARCH)/um/Kconfig" 90 91config MAY_HAVE_RUNTIME_DEPS 92 bool 93 94config STATIC_LINK 95 bool "Force a static link" 96 depends on !MAY_HAVE_RUNTIME_DEPS 97 help 98 This option gives you the ability to force a static link of UML. 99 Normally, UML is linked as a shared binary. This is inconvenient for 100 use in a chroot jail. So, if you intend to run UML inside a chroot, 101 you probably want to say Y here. 102 Additionally, this option enables using higher memory spaces (up to 103 2.75G) for UML. 104 105 NOTE: This option is incompatible with some networking features which 106 depend on features that require being dynamically loaded (like NSS). 107 108config LD_SCRIPT_STATIC 109 bool 110 default y 111 depends on STATIC_LINK 112 113config LD_SCRIPT_DYN 114 bool 115 default y 116 depends on !LD_SCRIPT_STATIC 117 118config LD_SCRIPT_DYN_RPATH 119 bool "set rpath in the binary" if EXPERT 120 default y 121 depends on LD_SCRIPT_DYN 122 help 123 Add /lib (and /lib64 for 64-bit) to the linux binary's rpath 124 explicitly. 125 126 You may need to turn this off if compiling for nix systems 127 that have their libraries in random /nix directories and 128 might otherwise unexpected use libraries from /lib or /lib64 129 instead of the desired ones. 130 131config HOSTFS 132 tristate "Host filesystem" 133 help 134 While the User-Mode Linux port uses its own root file system for 135 booting and normal file access, this module lets the UML user 136 access files stored on the host. It does not require any 137 network connection between the Host and UML. An example use of 138 this might be: 139 140 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare 141 142 where /tmp/fromhost is an empty directory inside UML and 143 /tmp/umlshare is a directory on the host with files the UML user 144 wishes to access. 145 146 For more information, see 147 <http://user-mode-linux.sourceforge.net/hostfs.html>. 148 149 If you'd like to be able to work with files stored on the host, 150 say Y or M here; otherwise say N. 151 152config MCONSOLE 153 bool "Management console" 154 depends on PROC_FS 155 default y 156 help 157 The user mode linux management console is a low-level interface to 158 the kernel, somewhat like the i386 SysRq interface. Since there is 159 a full-blown operating system running under every user mode linux 160 instance, there is much greater flexibility possible than with the 161 SysRq mechanism. 162 163 If you answer 'Y' to this option, to use this feature, you need the 164 mconsole client (called uml_mconsole) which is present in CVS in 165 2.4.5-9um and later (path /tools/mconsole), and is also in the 166 distribution RPM package in 2.4.6 and later. 167 168 It is safe to say 'Y' here. 169 170config MAGIC_SYSRQ 171 bool "Magic SysRq key" 172 depends on MCONSOLE 173 help 174 If you say Y here, you will have some control over the system even 175 if the system crashes for example during kernel debugging (e.g., you 176 will be able to flush the buffer cache to disk, reboot the system 177 immediately or dump some status information). A key for each of the 178 possible requests is provided. 179 180 This is the feature normally accomplished by pressing a key 181 while holding SysRq (Alt+PrintScreen). 182 183 On UML, this is accomplished by sending a "sysrq" command with 184 mconsole, followed by the letter for the requested command. 185 186 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y 187 unless you really know what this hack does. 188 189config KERNEL_STACK_ORDER 190 int "Kernel stack size order" 191 default 2 if 64BIT 192 range 2 10 if 64BIT 193 default 1 if !64BIT 194 help 195 This option determines the size of UML kernel stacks. They will 196 be 1 << order pages. The default is OK unless you're running Valgrind 197 on UML, in which case, set this to 3. 198 It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on 199 older (pre-2017) CPUs. It is not recommended on newer CPUs due to the 200 increase in the size of the state which needs to be saved when handling 201 signals. 202 203config MMAPPER 204 tristate "iomem emulation driver" 205 help 206 This driver allows a host file to be used as emulated IO memory inside 207 UML. 208 209config PGTABLE_LEVELS 210 int 211 default 4 if 64BIT 212 default 2 if !64BIT 213 214config UML_TIME_TRAVEL_SUPPORT 215 bool 216 prompt "Support time-travel mode (e.g. for test execution)" 217 # inf-cpu mode is incompatible with the benchmarking 218 depends on !RAID6_PQ_BENCHMARK 219 depends on !SMP 220 help 221 Enable this option to support time travel inside the UML instance. 222 223 After enabling this option, two modes are accessible at runtime 224 (selected by the kernel command line), see the kernel's command- 225 line help for more details. 226 227 It is safe to say Y, but you probably don't need this. 228 229config UML_MAX_USERSPACE_ITERATIONS 230 int 231 prompt "Maximum number of unscheduled userspace iterations" 232 default 10000 233 depends on UML_TIME_TRAVEL_SUPPORT 234 help 235 In UML inf-cpu and ext time-travel mode userspace can run without being 236 interrupted. This will eventually overwhelm the kernel and create OOM 237 situations (mainly RCU not running). This setting specifies the number 238 of kernel/userspace switches (minor/major page fault, signal or syscall) 239 for the same userspace thread before the sched_clock is advanced by a 240 jiffie to trigger scheduling. 241 242 Setting it to zero disables the feature. 243 244config KASAN_SHADOW_OFFSET 245 hex 246 depends on KASAN 247 default 0x100000000000 248 help 249 This is the offset at which the ~16TB of shadow memory is 250 mapped and used by KASAN for memory debugging. This can be any 251 address that has at least KASAN_SHADOW_SIZE (total address space divided 252 by 8) amount of space so that the KASAN shadow memory does not conflict 253 with anything. The default is 0x100000000000, which works even if mem is 254 set to a large value. On low-memory systems, try 0x7fff8000, as it fits 255 into the immediate of most instructions, improving performance. 256 257endmenu 258 259source "arch/um/drivers/Kconfig" 260 261config ARCH_SUSPEND_POSSIBLE 262 def_bool y 263 264menu "Power management options" 265 266source "kernel/power/Kconfig" 267 268endmenu 269