[linux-2.6-block.git] / arch / um / Kconfig

# SPDX-License-Identifier: GPL-2.0

menu "UML-specific options"

config UML
	bool
	default y
	select ARCH_HAS_KCOV
	select HAVE_ARCH_AUDITSYSCALL
	select HAVE_ARCH_SECCOMP_FILTER
	select HAVE_UID16
	select HAVE_FUTEX_CMPXCHG if FUTEX
	select HAVE_DEBUG_KMEMLEAK
	select GENERIC_IRQ_SHOW
	select GENERIC_CPU_DEVICES
	select GENERIC_CLOCKEVENTS
	select HAVE_GCC_PLUGINS
	select TTY # Needed for line.c

config MMU
	bool
	default y

config NO_IOMEM
	def_bool y

config ISA
	bool

config SBUS
	bool

config PCI
	bool

config PCMCIA
	bool

config TRACE_IRQFLAGS_SUPPORT
	bool
	default y

config LOCKDEP_SUPPORT
	bool
	default y

config STACKTRACE_SUPPORT
	bool
	default y
	select STACKTRACE

config GENERIC_CALIBRATE_DELAY
	bool
	default y

config HZ
	int
	default 100

config NR_CPUS
	int
	range 1 1
	default 1

source "arch/$(HEADER_ARCH)/um/Kconfig"

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.

config LD_SCRIPT_STATIC
	bool
	default y
	depends on STATIC_LINK

config LD_SCRIPT_DYN
	bool
	default y
	depends on !LD_SCRIPT_STATIC
        select MODULE_REL_CRCS if MODVERSIONS

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 MCONSOLE
	bool "Management console"
	depends on PROC_FS
	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/admin-guide/sysrq.rst>. Don't say Y
	  unless you really know what this hack does.

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 MMAPPER
	tristate "iomem emulation driver"
	help
	  This driver allows a host file to be used as emulated IO memory inside
	  UML.

config NO_DMA
	def_bool y

config PGTABLE_LEVELS
	int
	default 3 if 3_LEVEL_PGTABLES
	default 2

config SECCOMP
	def_bool y
	prompt "Enable seccomp to safely compute untrusted bytecode"
	---help---
	  This kernel feature is useful for number crunching applications
	  that may need to compute untrusted bytecode during their
	  execution. By using pipes or other transports made available to
	  the process as file descriptors supporting the read/write
	  syscalls, it's possible to isolate those applications in
	  their own address space using seccomp. Once seccomp is
	  enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
	  and the task is only allowed to execute a few safe syscalls
	  defined by each seccomp mode.

	  If unsure, say Y.

endmenu

source "arch/um/drivers/Kconfig"
Commit	Line	Data
79b05c1f CH	1	# SPDX-License-Identifier: GPL-2.0
79b05c1f CH	2
f163977d CH	3	menu "UML-specific options"
	4
	5	config UML
	6	bool
	7	default y
	8	select ARCH_HAS_KCOV
	9	select HAVE_ARCH_AUDITSYSCALL
	10	select HAVE_ARCH_SECCOMP_FILTER
	11	select HAVE_UID16
	12	select HAVE_FUTEX_CMPXCHG if FUTEX
	13	select HAVE_DEBUG_KMEMLEAK
	14	select GENERIC_IRQ_SHOW
	15	select GENERIC_CPU_DEVICES
	16	select GENERIC_CLOCKEVENTS
	17	select HAVE_GCC_PLUGINS
	18	select TTY # Needed for line.c
	19
	20	config MMU
	21	bool
	22	default y
	23
	24	config NO_IOMEM
	25	def_bool y
	26
	27	config ISA
	28	bool
	29
	30	config SBUS
	31	bool
	32
	33	config PCI
	34	bool
	35
	36	config PCMCIA
	37	bool
	38
	39	config TRACE_IRQFLAGS_SUPPORT
	40	bool
	41	default y
	42
	43	config LOCKDEP_SUPPORT
	44	bool
	45	default y
	46
	47	config STACKTRACE_SUPPORT
	48	bool
	49	default y
	50	select STACKTRACE
	51
	52	config GENERIC_CALIBRATE_DELAY
	53	bool
	54	default y
	55
	56	config HZ
	57	int
	58	default 100
	59
	60	config NR_CPUS
	61	int
	62	range 1 1
	63	default 1
	64
79b05c1f	65	source "arch/$(HEADER_ARCH)/um/Kconfig"
f163977d CH	66
	67	config STATIC_LINK
	68	bool "Force a static link"
	69	default n
	70	help
	71	This option gives you the ability to force a static link of UML.
	72	Normally, UML is linked as a shared binary. This is inconvenient for
	73	use in a chroot jail. So, if you intend to run UML inside a chroot,
	74	you probably want to say Y here.
	75	Additionally, this option enables using higher memory spaces (up to
	76	2.75G) for UML.
	77
f163977d CH	78	config LD_SCRIPT_STATIC
	79	bool
	80	default y
	81	depends on STATIC_LINK
	82
	83	config LD_SCRIPT_DYN
	84	bool
	85	default y
	86	depends on !LD_SCRIPT_STATIC
	87	select MODULE_REL_CRCS if MODVERSIONS
	88
f163977d CH	89	config HOSTFS
	90	tristate "Host filesystem"
	91	help
	92	While the User-Mode Linux port uses its own root file system for
	93	booting and normal file access, this module lets the UML user
	94	access files stored on the host. It does not require any
	95	network connection between the Host and UML. An example use of
	96	this might be:
	97
	98	mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
	99
	100	where /tmp/fromhost is an empty directory inside UML and
	101	/tmp/umlshare is a directory on the host with files the UML user
	102	wishes to access.
	103
	104	For more information, see
	105	<http://user-mode-linux.sourceforge.net/hostfs.html>.
	106
	107	If you'd like to be able to work with files stored on the host,
	108	say Y or M here; otherwise say N.
	109
	110	config MCONSOLE
	111	bool "Management console"
	112	depends on PROC_FS
	113	default y
	114	help
	115	The user mode linux management console is a low-level interface to
	116	the kernel, somewhat like the i386 SysRq interface. Since there is
	117	a full-blown operating system running under every user mode linux
	118	instance, there is much greater flexibility possible than with the
	119	SysRq mechanism.
	120
	121	If you answer 'Y' to this option, to use this feature, you need the
	122	mconsole client (called uml_mconsole) which is present in CVS in
	123	2.4.5-9um and later (path /tools/mconsole), and is also in the
	124	distribution RPM package in 2.4.6 and later.
	125
	126	It is safe to say 'Y' here.
	127
	128	config MAGIC_SYSRQ
	129	bool "Magic SysRq key"
	130	depends on MCONSOLE
	131	help
	132	If you say Y here, you will have some control over the system even
	133	if the system crashes for example during kernel debugging (e.g., you
	134	will be able to flush the buffer cache to disk, reboot the system
	135	immediately or dump some status information). A key for each of the
	136	possible requests is provided.
	137
	138	This is the feature normally accomplished by pressing a key
	139	while holding SysRq (Alt+PrintScreen).
	140
	141	On UML, this is accomplished by sending a "sysrq" command with
	142	mconsole, followed by the letter for the requested command.
	143
	144	The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y
	145	unless you really know what this hack does.
	146
	147	config KERNEL_STACK_ORDER
	148	int "Kernel stack size order"
	149	default 1 if 64BIT
	150	range 1 10 if 64BIT
	151	default 0 if !64BIT
	152	help
153	This option determines the size of UML kernel stacks. They will
154	be 1 << order pages. The default is OK unless you're running Valgrind
155	on UML, in which case, set this to 3.
156
157	config MMAPPER
158	tristate "iomem emulation driver"
159	help
160	This driver allows a host file to be used as emulated IO memory inside
161	UML.
162
163	config NO_DMA
164	def_bool y
165
166	config PGTABLE_LEVELS
167	int
168	default 3 if 3_LEVEL_PGTABLES
169	default 2
170
171	config SECCOMP
172	def_bool y
173	prompt "Enable seccomp to safely compute untrusted bytecode"
174	---help---
175	This kernel feature is useful for number crunching applications
176	that may need to compute untrusted bytecode during their
177	execution. By using pipes or other transports made available to
178	the process as file descriptors supporting the read/write
179	syscalls, it's possible to isolate those applications in
180	their own address space using seccomp. Once seccomp is
181	enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
182	and the task is only allowed to execute a few safe syscalls
183	defined by each seccomp mode.
184
185	If unsure, say Y.
186
187	endmenu
188
9bea1801	189	source "arch/um/drivers/Kconfig"