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linux/arch/um/Kconfig
Jeff Dike 536788fe2d uml: runtime host VMSPLIT detection 
Calculate TASK_SIZE at run-time by figuring out the host's VMSPLIT - this is
needed on i386 if UML is to run on hosts with varying VMSPLITs without
recompilation.

TASK_SIZE is now defined in terms of a variable, task_size.  This gets rid of
an include of pgtable.h from processor.h, which can cause include loops.

On i386, task_size is calculated early in boot by probing the address space in
a binary search to figure out where the boundary between usable and non-usable
memory is.  This tries to make sure that a page that is considered to be in
userspace is, or can be made, read-write.  I'm concerned about a system-global
VDSO page in kernel memory being hit and considered to be a userspace page.

On x86_64, task_size is just the old value of CONFIG_TOP_ADDR.

A bunch of config variable are gone now.  CONFIG_TOP_ADDR is directly replaced
by TASK_SIZE.  NEST_LEVEL is gone since the relocation of the stubs makes it
irrelevant.  All the HOST_VMSPLIT stuff is gone.  All references to these in
arch/um/Makefile are also gone.

I noticed and fixed a missing extern in os.h when adding os_get_task_size.

Note: This has been revised to fix the 32-bit UML on 64-bit host bug that
Miklos ran into.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 09:22:42 -08:00

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config DEFCONFIG_LIST
string
option defconfig_list
default "arch/$ARCH/defconfig"
# UML uses the generic IRQ subsystem
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
config GENERIC_TIME
bool
default y
config GENERIC_CLOCKEVENTS
bool
default y
# Used in kernel/irq/manage.c and include/linux/irq.h
config IRQ_RELEASE_METHOD
bool
default y
config HZ
int
default 100
menu "UML-specific options"
config STATIC_LINK
bool "Force a static link"
default n
help
This option gives you the ability to force a static link of UML.
Normally, UML is linked as a shared binary. This is inconvenient for
use in a chroot jail. So, if you intend to run UML inside a chroot,
you probably want to say Y here.
Additionally, this option enables using higher memory spaces (up to
2.75G) for UML.
source "arch/um/Kconfig.arch"
source "mm/Kconfig"
source "kernel/time/Kconfig"
config LD_SCRIPT_STATIC
bool
default y
depends on STATIC_LINK
config LD_SCRIPT_DYN
bool
default y
depends on !LD_SCRIPT_STATIC
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
<http://user-mode-linux.sourceforge.net/hostfs.html>.
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 <http://user-mode-linux.sf.net/old/hppfs.html> 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 <file:Documentation/sysrq.txt>. Don't say Y
unless you really know what this hack does.
config SMP
bool "Symmetric multi-processing support (EXPERIMENTAL)"
default n
depends on 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 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 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.
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"
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