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_KCOV 10 select ARCH_NO_PREEMPT 11 select HAVE_ARCH_AUDITSYSCALL 12 select HAVE_ARCH_SECCOMP_FILTER 13 select HAVE_ASM_MODVERSIONS 14 select HAVE_UID16 15 select HAVE_FUTEX_CMPXCHG if FUTEX 16 select HAVE_DEBUG_KMEMLEAK 17 select HAVE_DEBUG_BUGVERBOSE 18 select NO_DMA if !UML_DMA_EMULATION 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 UML_DMA_EMULATION 30 bool 31 32config NO_IOMEM 33 bool "disable IOMEM" if EXPERT 34 depends on !INDIRECT_IOMEM 35 default y 36 37config UML_IOMEM_EMULATION 38 bool 39 select INDIRECT_IOMEM 40 select GENERIC_PCI_IOMAP 41 select GENERIC_IOMAP 42 select NO_GENERIC_PCI_IOPORT_MAP 43 44config NO_IOPORT_MAP 45 def_bool y 46 47config ISA 48 bool 49 50config SBUS 51 bool 52 53config TRACE_IRQFLAGS_SUPPORT 54 bool 55 default y 56 57config LOCKDEP_SUPPORT 58 bool 59 default y 60 61config STACKTRACE_SUPPORT 62 bool 63 default y 64 select STACKTRACE 65 66config GENERIC_CALIBRATE_DELAY 67 bool 68 default y 69 70config HZ 71 int 72 default 100 73 74config NR_CPUS 75 int 76 range 1 1 77 default 1 78 79source "arch/$(HEADER_ARCH)/um/Kconfig" 80 81config MAY_HAVE_RUNTIME_DEPS 82 bool 83 84config STATIC_LINK 85 bool "Force a static link" 86 depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS 87 help 88 This option gives you the ability to force a static link of UML. 89 Normally, UML is linked as a shared binary. This is inconvenient for 90 use in a chroot jail. So, if you intend to run UML inside a chroot, 91 you probably want to say Y here. 92 Additionally, this option enables using higher memory spaces (up to 93 2.75G) for UML. 94 95 NOTE: This option is incompatible with some networking features which 96 depend on features that require being dynamically loaded (like NSS). 97 98config LD_SCRIPT_STATIC 99 bool 100 default y 101 depends on STATIC_LINK 102 103config LD_SCRIPT_DYN 104 bool 105 default y 106 depends on !LD_SCRIPT_STATIC 107 select MODULE_REL_CRCS if MODVERSIONS 108 109config HOSTFS 110 tristate "Host filesystem" 111 help 112 While the User-Mode Linux port uses its own root file system for 113 booting and normal file access, this module lets the UML user 114 access files stored on the host. It does not require any 115 network connection between the Host and UML. An example use of 116 this might be: 117 118 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare 119 120 where /tmp/fromhost is an empty directory inside UML and 121 /tmp/umlshare is a directory on the host with files the UML user 122 wishes to access. 123 124 For more information, see 125 <http://user-mode-linux.sourceforge.net/hostfs.html>. 126 127 If you'd like to be able to work with files stored on the host, 128 say Y or M here; otherwise say N. 129 130config MCONSOLE 131 bool "Management console" 132 depends on PROC_FS 133 default y 134 help 135 The user mode linux management console is a low-level interface to 136 the kernel, somewhat like the i386 SysRq interface. Since there is 137 a full-blown operating system running under every user mode linux 138 instance, there is much greater flexibility possible than with the 139 SysRq mechanism. 140 141 If you answer 'Y' to this option, to use this feature, you need the 142 mconsole client (called uml_mconsole) which is present in CVS in 143 2.4.5-9um and later (path /tools/mconsole), and is also in the 144 distribution RPM package in 2.4.6 and later. 145 146 It is safe to say 'Y' here. 147 148config MAGIC_SYSRQ 149 bool "Magic SysRq key" 150 depends on MCONSOLE 151 help 152 If you say Y here, you will have some control over the system even 153 if the system crashes for example during kernel debugging (e.g., you 154 will be able to flush the buffer cache to disk, reboot the system 155 immediately or dump some status information). A key for each of the 156 possible requests is provided. 157 158 This is the feature normally accomplished by pressing a key 159 while holding SysRq (Alt+PrintScreen). 160 161 On UML, this is accomplished by sending a "sysrq" command with 162 mconsole, followed by the letter for the requested command. 163 164 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y 165 unless you really know what this hack does. 166 167config KERNEL_STACK_ORDER 168 int "Kernel stack size order" 169 default 2 if 64BIT 170 range 2 10 if 64BIT 171 default 1 if !64BIT 172 help 173 This option determines the size of UML kernel stacks. They will 174 be 1 << order pages. The default is OK unless you're running Valgrind 175 on UML, in which case, set this to 3. 176 It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on 177 older (pre-2017) CPUs. It is not recommended on newer CPUs due to the 178 increase in the size of the state which needs to be saved when handling 179 signals. 180 181config MMAPPER 182 tristate "iomem emulation driver" 183 help 184 This driver allows a host file to be used as emulated IO memory inside 185 UML. 186 187config PGTABLE_LEVELS 188 int 189 default 3 if 3_LEVEL_PGTABLES 190 default 2 191 192config UML_TIME_TRAVEL_SUPPORT 193 bool 194 prompt "Support time-travel mode (e.g. for test execution)" 195 # inf-cpu mode is incompatible with the benchmarking 196 depends on !RAID6_PQ_BENCHMARK 197 depends on !SMP 198 help 199 Enable this option to support time travel inside the UML instance. 200 201 After enabling this option, two modes are accessible at runtime 202 (selected by the kernel command line), see the kernel's command- 203 line help for more details. 204 205 It is safe to say Y, but you probably don't need this. 206 207endmenu 208 209source "arch/um/drivers/Kconfig" 210 211config ARCH_SUSPEND_POSSIBLE 212 def_bool y 213 214source "kernel/power/Kconfig" 215