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_UID16 13 select HAVE_FUTEX_CMPXCHG if FUTEX 14 select HAVE_DEBUG_KMEMLEAK 15 select GENERIC_IRQ_SHOW 16 select GENERIC_CPU_DEVICES 17 select GENERIC_CLOCKEVENTS 18 select HAVE_GCC_PLUGINS 19 select TTY # Needed for line.c 20 21config MMU 22 bool 23 default y 24 25config NO_IOMEM 26 def_bool y 27 28config ISA 29 bool 30 31config SBUS 32 bool 33 34config PCI 35 bool 36 37config PCMCIA 38 bool 39 40config TRACE_IRQFLAGS_SUPPORT 41 bool 42 default y 43 44config LOCKDEP_SUPPORT 45 bool 46 default y 47 48config STACKTRACE_SUPPORT 49 bool 50 default y 51 select STACKTRACE 52 53config GENERIC_CALIBRATE_DELAY 54 bool 55 default y 56 57config HZ 58 int 59 default 100 60 61config NR_CPUS 62 int 63 range 1 1 64 default 1 65 66source "arch/$(HEADER_ARCH)/um/Kconfig" 67 68config STATIC_LINK 69 bool "Force a static link" 70 default n 71 help 72 This option gives you the ability to force a static link of UML. 73 Normally, UML is linked as a shared binary. This is inconvenient for 74 use in a chroot jail. So, if you intend to run UML inside a chroot, 75 you probably want to say Y here. 76 Additionally, this option enables using higher memory spaces (up to 77 2.75G) for UML. 78 79config LD_SCRIPT_STATIC 80 bool 81 default y 82 depends on STATIC_LINK 83 84config LD_SCRIPT_DYN 85 bool 86 default y 87 depends on !LD_SCRIPT_STATIC 88 select MODULE_REL_CRCS if MODVERSIONS 89 90config HOSTFS 91 tristate "Host filesystem" 92 help 93 While the User-Mode Linux port uses its own root file system for 94 booting and normal file access, this module lets the UML user 95 access files stored on the host. It does not require any 96 network connection between the Host and UML. An example use of 97 this might be: 98 99 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare 100 101 where /tmp/fromhost is an empty directory inside UML and 102 /tmp/umlshare is a directory on the host with files the UML user 103 wishes to access. 104 105 For more information, see 106 <http://user-mode-linux.sourceforge.net/hostfs.html>. 107 108 If you'd like to be able to work with files stored on the host, 109 say Y or M here; otherwise say N. 110 111config MCONSOLE 112 bool "Management console" 113 depends on PROC_FS 114 default y 115 help 116 The user mode linux management console is a low-level interface to 117 the kernel, somewhat like the i386 SysRq interface. Since there is 118 a full-blown operating system running under every user mode linux 119 instance, there is much greater flexibility possible than with the 120 SysRq mechanism. 121 122 If you answer 'Y' to this option, to use this feature, you need the 123 mconsole client (called uml_mconsole) which is present in CVS in 124 2.4.5-9um and later (path /tools/mconsole), and is also in the 125 distribution RPM package in 2.4.6 and later. 126 127 It is safe to say 'Y' here. 128 129config MAGIC_SYSRQ 130 bool "Magic SysRq key" 131 depends on MCONSOLE 132 help 133 If you say Y here, you will have some control over the system even 134 if the system crashes for example during kernel debugging (e.g., you 135 will be able to flush the buffer cache to disk, reboot the system 136 immediately or dump some status information). A key for each of the 137 possible requests is provided. 138 139 This is the feature normally accomplished by pressing a key 140 while holding SysRq (Alt+PrintScreen). 141 142 On UML, this is accomplished by sending a "sysrq" command with 143 mconsole, followed by the letter for the requested command. 144 145 The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y 146 unless you really know what this hack does. 147 148config KERNEL_STACK_ORDER 149 int "Kernel stack size order" 150 default 1 if 64BIT 151 range 1 10 if 64BIT 152 default 0 if !64BIT 153 help 154 This option determines the size of UML kernel stacks. They will 155 be 1 << order pages. The default is OK unless you're running Valgrind 156 on UML, in which case, set this to 3. 157 158config MMAPPER 159 tristate "iomem emulation driver" 160 help 161 This driver allows a host file to be used as emulated IO memory inside 162 UML. 163 164config NO_DMA 165 def_bool y 166 167config PGTABLE_LEVELS 168 int 169 default 3 if 3_LEVEL_PGTABLES 170 default 2 171 172config SECCOMP 173 def_bool y 174 prompt "Enable seccomp to safely compute untrusted bytecode" 175 ---help--- 176 This kernel feature is useful for number crunching applications 177 that may need to compute untrusted bytecode during their 178 execution. By using pipes or other transports made available to 179 the process as file descriptors supporting the read/write 180 syscalls, it's possible to isolate those applications in 181 their own address space using seccomp. Once seccomp is 182 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled 183 and the task is only allowed to execute a few safe syscalls 184 defined by each seccomp mode. 185 186 If unsure, say Y. 187 188endmenu 189 190source "arch/um/drivers/Kconfig" 191