config DEFCONFIG_LIST string option defconfig_list default "arch/$ARCH/defconfig" # UML uses the generic IRQ sugsystem config GENERIC_HARDIRQS bool default y config UML bool default y config MMU bool default y config NO_IOMEM def_bool y mainmenu "Linux/Usermode Kernel Configuration" config ISA bool config SBUS bool config PCI bool config PCMCIA bool # Yet to do! config TRACE_IRQFLAGS_SUPPORT bool default n config LOCKDEP_SUPPORT bool default y config STACKTRACE_SUPPORT bool default n config GENERIC_CALIBRATE_DELAY bool default y config GENERIC_BUG bool default y depends on BUG # Used in kernel/irq/manage.c and include/linux/irq.h config IRQ_RELEASE_METHOD bool default y menu "UML-specific options" config MODE_TT bool "Tracing thread support (DEPRECATED)" default n depends on BROKEN help This option controls whether tracing thread support is compiled into UML. This option is largely obsolete, given that skas0 provides skas security and performance without needing to patch the host. It is safe to say 'N' here; saying 'Y' may cause additional problems with the resulting binary even if you run UML in SKAS mode, and running in TT mode is strongly *NOT RECOMMENDED*. config STATIC_LINK bool "Force a static link" default n depends on !MODE_TT help If CONFIG_MODE_TT is disabled, then this option gives you the ability to force a static link of UML. Normally, if only skas mode is built in to UML, it will be linked as a shared binary. This is inconvenient for use in a chroot jail. So, if you intend to run UML inside a chroot, and you disable CONFIG_MODE_TT, you probably want to say Y here. Additionally, this option enables using higher memory spaces (up to 2.75G) for UML - disabling CONFIG_MODE_TT and enabling this option leads to best results for this. config KERNEL_HALF_GIGS int "Kernel address space size (in .5G units)" default "1" depends on MODE_TT help This determines the amount of address space that UML will allocate for its own, measured in half Gigabyte units. The default is 1. Change this only if you need to boot UML with an unusually large amount of physical memory. config MODE_SKAS bool "Separate Kernel Address Space support" if MODE_TT default y help This option controls whether skas (separate kernel address space) support is compiled in. Unless you have specific needs to use TT mode (which applies almost only to developers), you should say Y here. SKAS mode will make use of the SKAS3 patch if it is applied on the host (and your UML will run in SKAS3 mode), but if no SKAS patch is applied on the host it will run in SKAS0 mode, which is anyway faster than TT mode. source "arch/um/Kconfig.arch" source "mm/Kconfig" config LD_SCRIPT_STATIC bool default y depends on MODE_TT || STATIC_LINK config LD_SCRIPT_DYN bool default y depends on !LD_SCRIPT_STATIC config NET bool "Networking support" help Unless you really know what you are doing, you should say Y here. The reason is that some programs need kernel networking support even when running on a stand-alone machine that isn't connected to any other computer. If you are upgrading from an older kernel, you should consider updating your networking tools too because changes in the kernel and the tools often go hand in hand. The tools are contained in the package net-tools, the location and version number of which are given in . For a general introduction to Linux networking, it is highly recommended to read the NET-HOWTO, available from . source "fs/Kconfig.binfmt" config HOSTFS tristate "Host filesystem" help While the User-Mode Linux port uses its own root file system for booting and normal file access, this module lets the UML user access files stored on the host. It does not require any network connection between the Host and UML. An example use of this might be: mount none /tmp/fromhost -t hostfs -o /tmp/umlshare where /tmp/fromhost is an empty directory inside UML and /tmp/umlshare is a directory on the host with files the UML user wishes to access. For more information, see . If you'd like to be able to work with files stored on the host, say Y or M here; otherwise say N. config HPPFS tristate "HoneyPot ProcFS (EXPERIMENTAL)" depends on EXPERIMENTAL help hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc entries to be overridden, removed, or fabricated from the host. Its purpose is to allow a UML to appear to be a physical machine by removing or changing anything in /proc which gives away the identity of a UML. See for more information. You only need this if you are setting up a UML honeypot. Otherwise, it is safe to say 'N' here. config MCONSOLE bool "Management console" default y help The user mode linux management console is a low-level interface to the kernel, somewhat like the i386 SysRq interface. Since there is a full-blown operating system running under every user mode linux instance, there is much greater flexibility possible than with the SysRq mechanism. If you answer 'Y' to this option, to use this feature, you need the mconsole client (called uml_mconsole) which is present in CVS in 2.4.5-9um and later (path /tools/mconsole), and is also in the distribution RPM package in 2.4.6 and later. It is safe to say 'Y' here. config MAGIC_SYSRQ bool "Magic SysRq key" depends on MCONSOLE ---help--- If you say Y here, you will have some control over the system even if the system crashes for example during kernel debugging (e.g., you will be able to flush the buffer cache to disk, reboot the system immediately or dump some status information). A key for each of the possible requests is provided. This is the feature normally accomplished by pressing a key while holding SysRq (Alt+PrintScreen). On UML, this is accomplished by sending a "sysrq" command with mconsole, followed by the letter for the requested command. The keys are documented in . Don't say Y unless you really know what this hack does. config SMP bool "Symmetric multi-processing support (EXPERIMENTAL)" default n #SMP_BROKEN is for x86_64. depends on MODE_TT && EXPERIMENTAL && (!SMP_BROKEN || (BROKEN && SMP_BROKEN)) help This option enables UML SMP support. It is NOT related to having a real SMP box. Not directly, at least. UML implements virtual SMP by allowing as many processes to run simultaneously on the host as there are virtual processors configured. Obviously, if the host is a uniprocessor, those processes will timeshare, but, inside UML, will appear to be running simultaneously. If the host is a multiprocessor, then UML processes may run simultaneously, depending on the host scheduler. This, however, is supported only in TT mode. So, if you use the SKAS patch on your host, switching to TT mode and enabling SMP usually gives you worse performances. Also, since the support for SMP has been under-developed, there could be some bugs being exposed by enabling SMP. If you don't know what to do, say N. config NR_CPUS int "Maximum number of CPUs (2-32)" range 2 32 depends on SMP default "32" config NEST_LEVEL int "Nesting level" default "0" help This is set to the number of layers of UMLs that this UML will be run in. Normally, this is zero, meaning that it will run directly on the host. Setting it to one will build a UML that can run inside a UML that is running on the host. Generally, if you intend this UML to run inside another UML, set CONFIG_NEST_LEVEL to one more than the host UML. Note that if the hosting UML has its CONFIG_KERNEL_HALF_GIGS set to greater than one, then the guest UML should have its CONFIG_NEST_LEVEL set to the host's CONFIG_NEST_LEVEL + CONFIG_KERNEL_HALF_GIGS. Only change this if you are running nested UMLs. config HIGHMEM bool "Highmem support (EXPERIMENTAL)" depends on !64BIT && EXPERIMENTAL default n help This was used to allow UML to run with big amounts of memory. Currently it is unstable, so if unsure say N. To use big amounts of memory, it is recommended to disable TT mode (i.e. CONFIG_MODE_TT) and enable static linking (i.e. CONFIG_STATIC_LINK) - this should allow the guest to use up to 2.75G of memory. config KERNEL_STACK_ORDER int "Kernel stack size order" default 1 if 64BIT range 1 10 if 64BIT default 0 if !64BIT help This option determines the size of UML kernel stacks. They will be 1 << order pages. The default is OK unless you're running Valgrind on UML, in which case, set this to 3. config UML_REAL_TIME_CLOCK bool "Real-time Clock" default y help This option makes UML time deltas match wall clock deltas. This should normally be enabled. The exception would be if you are debugging with UML and spend long times with UML stopped at a breakpoint. In this case, when UML is restarted, it will call the timer enough times to make up for the time spent at the breakpoint. This could result in a noticeable lag. If this is a problem, then disable this option. endmenu source "init/Kconfig" source "drivers/block/Kconfig" source "arch/um/Kconfig.char" source "drivers/base/Kconfig" source "net/Kconfig" source "arch/um/Kconfig.net" source "drivers/net/Kconfig" source "drivers/connector/Kconfig" source "fs/Kconfig" source "security/Kconfig" source "crypto/Kconfig" source "lib/Kconfig" source "drivers/scsi/Kconfig" source "drivers/md/Kconfig" if BROKEN source "drivers/mtd/Kconfig" endif #This is just to shut up some Kconfig warnings, so no prompt. config INPUT bool default n source "arch/um/Kconfig.debug"