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