1# SPDX-License-Identifier: GPL-2.0 2 3menu "UML-specific options" 4 5config UML 6 bool 7 default y 8 select ARCH_HAS_KCOV 9 select ARCH_NO_PREEMPT 10 select HAVE_ARCH_AUDITSYSCALL 11 select HAVE_ARCH_SECCOMP_FILTER 12 select HAVE_ASM_MODVERSIONS 13 select HAVE_UID16 14 select HAVE_FUTEX_CMPXCHG if FUTEX 15 select HAVE_DEBUG_KMEMLEAK 16 select HAVE_DEBUG_BUGVERBOSE 17 select NO_DMA 18 select ARCH_HAS_SET_MEMORY 19 select GENERIC_IRQ_SHOW 20 select GENERIC_CPU_DEVICES 21 select HAVE_GCC_PLUGINS 22 select SET_FS 23 select TTY # Needed for line.c 24 25config MMU 26 bool 27 default y 28 29config NO_IOMEM 30 def_bool y 31 32config ISA 33 bool 34 35config SBUS 36 bool 37 38config TRACE_IRQFLAGS_SUPPORT 39 bool 40 default y 41 42config LOCKDEP_SUPPORT 43 bool 44 default y 45 46config STACKTRACE_SUPPORT 47 bool 48 default y 49 select STACKTRACE 50 51config GENERIC_CALIBRATE_DELAY 52 bool 53 default y 54 55config HZ 56 int 57 default 100 58 59config NR_CPUS 60 int 61 range 1 1 62 default 1 63 64source "arch/$(HEADER_ARCH)/um/Kconfig" 65 66config MAY_HAVE_RUNTIME_DEPS 67 bool 68 69config STATIC_LINK 70 bool "Force a static link" 71 depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS 72 help 73 This option gives you the ability to force a static link of UML. 74 Normally, UML is linked as a shared binary. This is inconvenient for 75 use in a chroot jail. So, if you intend to run UML inside a chroot, 76 you probably want to say Y here. 77 Additionally, this option enables using higher memory spaces (up to 78 2.75G) for UML. 79 80 NOTE: This option is incompatible with some networking features which 81 depend on features that require being dynamically loaded (like NSS). 82 83config LD_SCRIPT_STATIC 84 bool 85 default y 86 depends on STATIC_LINK 87 88config LD_SCRIPT_DYN 89 bool 90 default y 91 depends on !LD_SCRIPT_STATIC 92 select MODULE_REL_CRCS if MODVERSIONS 93 94config HOSTFS 95 tristate "Host filesystem" 96 help 97 While the User-Mode Linux port uses its own root file system for 98 booting and normal file access, this module lets the UML user 99 access files stored on the host. It does not require any 100 network connection between the Host and UML. An example use of 101 this might be: 102 103 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare 104 105 where /tmp/fromhost is an empty directory inside UML and 106 /tmp/umlshare is a directory on the host with files the UML user 107 wishes to access. 108 109 For more information, see 110 <http://user-mode-linux.sourceforge.net/hostfs.html>. 111 112 If you'd like to be able to work with files stored on the host, 113 say Y or M here; otherwise say N. 114 115config MCONSOLE 116 bool "Management console" 117 depends on PROC_FS 118 default y 119 help 120 The user mode linux management console is a low-level interface to 121 the kernel, somewhat like the i386 SysRq interface. Since there is 122 a full-blown operating system running under every user mode linux 123 instance, there is much greater flexibility possible than with the 124 SysRq mechanism. 125 126 If you answer 'Y' to this option, to use this feature, you need the 127 mconsole client (called uml_mconsole) which is present in CVS in 128 2.4.5-9um and later (path /tools/mconsole), and is also in the 129 distribution RPM package in 2.4.6 and later. 130 131 It is safe to say 'Y' here. 132 133config MAGIC_SYSRQ 134 bool "Magic SysRq key" 135 depends on MCONSOLE 136 help 137 If you say Y here, you will have some control over the system even 138 if the system crashes for example during kernel debugging (e.g., you 139 will be able to flush the buffer cache to disk, reboot the system 140 immediately or dump some status information). A key for each of the 141 possible requests is provided. 142 143 This is the feature normally accomplished by pressing a key 144 while holding SysRq (Alt+PrintScreen). 145 146 On UML, this is accomplished by sending a "sysrq" command with 147 mconsole, followed by the letter for the requested command. 148 149 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y 150 unless you really know what this hack does. 151 152config KERNEL_STACK_ORDER 153 int "Kernel stack size order" 154 default 2 if 64BIT 155 range 2 10 if 64BIT 156 default 1 if !64BIT 157 help 158 This option determines the size of UML kernel stacks. They will 159 be 1 << order pages. The default is OK unless you're running Valgrind 160 on UML, in which case, set this to 3. 161 It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on 162 older (pre-2017) CPUs. It is not recommended on newer CPUs due to the 163 increase in the size of the state which needs to be saved when handling 164 signals. 165 166config MMAPPER 167 tristate "iomem emulation driver" 168 help 169 This driver allows a host file to be used as emulated IO memory inside 170 UML. 171 172config PGTABLE_LEVELS 173 int 174 default 3 if 3_LEVEL_PGTABLES 175 default 2 176 177config UML_TIME_TRAVEL_SUPPORT 178 bool 179 prompt "Support time-travel mode (e.g. for test execution)" 180 # inf-cpu mode is incompatible with the benchmarking 181 depends on !RAID6_PQ_BENCHMARK 182 depends on !SMP 183 help 184 Enable this option to support time travel inside the UML instance. 185 186 After enabling this option, two modes are accessible at runtime 187 (selected by the kernel command line), see the kernel's command- 188 line help for more details. 189 190 It is safe to say Y, but you probably don't need this. 191 192endmenu 193 194source "arch/um/drivers/Kconfig" 195 196config ARCH_SUSPEND_POSSIBLE 197 def_bool y 198 199source "kernel/power/Kconfig" 200