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1config STATIC_LINK
2 bool "Force a static link"
3 default n
4 help
5 This option gives you the ability to force a static link of UML.
6 Normally, UML is linked as a shared binary. This is inconvenient for
7 use in a chroot jail. So, if you intend to run UML inside a chroot,
8 you probably want to say Y here.
9 Additionally, this option enables using higher memory spaces (up to
10 2.75G) for UML.
11
12source "mm/Kconfig"
13
14config LD_SCRIPT_STATIC
15 bool
16 default y
17 depends on STATIC_LINK
18
19config LD_SCRIPT_DYN
20 bool
21 default y
22 depends on !LD_SCRIPT_STATIC
23
24source "fs/Kconfig.binfmt"
25
26config HOSTFS
27 tristate "Host filesystem"
28 help
29 While the User-Mode Linux port uses its own root file system for
30 booting and normal file access, this module lets the UML user
31 access files stored on the host. It does not require any
32 network connection between the Host and UML. An example use of
33 this might be:
34
35 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
36
37 where /tmp/fromhost is an empty directory inside UML and
38 /tmp/umlshare is a directory on the host with files the UML user
39 wishes to access.
40
41 For more information, see
42 <http://user-mode-linux.sourceforge.net/hostfs.html>.
43
44 If you'd like to be able to work with files stored on the host,
45 say Y or M here; otherwise say N.
46
47config HPPFS
48 tristate "HoneyPot ProcFS (EXPERIMENTAL)"
49 depends on EXPERIMENTAL && PROC_FS
50 help
51 hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc
52 entries to be overridden, removed, or fabricated from the host.
53 Its purpose is to allow a UML to appear to be a physical machine
54 by removing or changing anything in /proc which gives away the
55 identity of a UML.
56
57 See <http://user-mode-linux.sf.net/old/hppfs.html> for more information.
58
59 You only need this if you are setting up a UML honeypot. Otherwise,
60 it is safe to say 'N' here.
61
62config MCONSOLE
63 bool "Management console"
64 default y
65 help
66 The user mode linux management console is a low-level interface to
67 the kernel, somewhat like the i386 SysRq interface. Since there is
68 a full-blown operating system running under every user mode linux
69 instance, there is much greater flexibility possible than with the
70 SysRq mechanism.
71
72 If you answer 'Y' to this option, to use this feature, you need the
73 mconsole client (called uml_mconsole) which is present in CVS in
74 2.4.5-9um and later (path /tools/mconsole), and is also in the
75 distribution RPM package in 2.4.6 and later.
76
77 It is safe to say 'Y' here.
78
79config MAGIC_SYSRQ
80 bool "Magic SysRq key"
81 depends on MCONSOLE
82 help
83 If you say Y here, you will have some control over the system even
84 if the system crashes for example during kernel debugging (e.g., you
85 will be able to flush the buffer cache to disk, reboot the system
86 immediately or dump some status information). A key for each of the
87 possible requests is provided.
88
89 This is the feature normally accomplished by pressing a key
90 while holding SysRq (Alt+PrintScreen).
91
92 On UML, this is accomplished by sending a "sysrq" command with
93 mconsole, followed by the letter for the requested command.
94
95 The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
96 unless you really know what this hack does.
97
98config SMP
99 bool "Symmetric multi-processing support (EXPERIMENTAL)"
100 default n
101 depends on BROKEN
102 help
103 This option enables UML SMP support.
104 It is NOT related to having a real SMP box. Not directly, at least.
105
106 UML implements virtual SMP by allowing as many processes to run
107 simultaneously on the host as there are virtual processors configured.
108
109 Obviously, if the host is a uniprocessor, those processes will
110 timeshare, but, inside UML, will appear to be running simultaneously.
111 If the host is a multiprocessor, then UML processes may run
112 simultaneously, depending on the host scheduler.
113
114 This, however, is supported only in TT mode. So, if you use the SKAS
115 patch on your host, switching to TT mode and enabling SMP usually
116 gives you worse performances.
117 Also, since the support for SMP has been under-developed, there could
118 be some bugs being exposed by enabling SMP.
119
120 If you don't know what to do, say N.
121
122config NR_CPUS
123 int "Maximum number of CPUs (2-32)"
124 range 2 32
125 depends on SMP
126 default "32"
127
128config HIGHMEM
129 bool "Highmem support (EXPERIMENTAL)"
130 depends on !64BIT && BROKEN
131 default n
132 help
133 This was used to allow UML to run with big amounts of memory.
134 Currently it is unstable, so if unsure say N.
135
136 To use big amounts of memory, it is recommended enable static
137 linking (i.e. CONFIG_STATIC_LINK) - this should allow the
138 guest to use up to 2.75G of memory.
139
140config KERNEL_STACK_ORDER
141 int "Kernel stack size order"
142 default 1 if 64BIT
143 range 1 10 if 64BIT
144 default 0 if !64BIT
145 help
146 This option determines the size of UML kernel stacks. They will
147 be 1 << order pages. The default is OK unless you're running Valgrind
148 on UML, in which case, set this to 3.
149
150config MMAPPER
151 tristate "iomem emulation driver"
152 help
153 This driver allows a host file to be used as emulated IO memory inside
154 UML.
155
156config NO_DMA
157 def_bool y
1# SPDX-License-Identifier: GPL-2.0
2config STATIC_LINK
3 bool "Force a static link"
4 default n
5 help
6 This option gives you the ability to force a static link of UML.
7 Normally, UML is linked as a shared binary. This is inconvenient for
8 use in a chroot jail. So, if you intend to run UML inside a chroot,
9 you probably want to say Y here.
10 Additionally, this option enables using higher memory spaces (up to
11 2.75G) for UML.
12
13source "mm/Kconfig"
14
15config LD_SCRIPT_STATIC
16 bool
17 default y
18 depends on STATIC_LINK
19
20config LD_SCRIPT_DYN
21 bool
22 default y
23 depends on !LD_SCRIPT_STATIC
24 select MODULE_REL_CRCS if MODVERSIONS
25
26source "fs/Kconfig.binfmt"
27
28config HOSTFS
29 tristate "Host filesystem"
30 help
31 While the User-Mode Linux port uses its own root file system for
32 booting and normal file access, this module lets the UML user
33 access files stored on the host. It does not require any
34 network connection between the Host and UML. An example use of
35 this might be:
36
37 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
38
39 where /tmp/fromhost is an empty directory inside UML and
40 /tmp/umlshare is a directory on the host with files the UML user
41 wishes to access.
42
43 For more information, see
44 <http://user-mode-linux.sourceforge.net/hostfs.html>.
45
46 If you'd like to be able to work with files stored on the host,
47 say Y or M here; otherwise say N.
48
49config MCONSOLE
50 bool "Management console"
51 depends on PROC_FS
52 default y
53 help
54 The user mode linux management console is a low-level interface to
55 the kernel, somewhat like the i386 SysRq interface. Since there is
56 a full-blown operating system running under every user mode linux
57 instance, there is much greater flexibility possible than with the
58 SysRq mechanism.
59
60 If you answer 'Y' to this option, to use this feature, you need the
61 mconsole client (called uml_mconsole) which is present in CVS in
62 2.4.5-9um and later (path /tools/mconsole), and is also in the
63 distribution RPM package in 2.4.6 and later.
64
65 It is safe to say 'Y' here.
66
67config MAGIC_SYSRQ
68 bool "Magic SysRq key"
69 depends on MCONSOLE
70 help
71 If you say Y here, you will have some control over the system even
72 if the system crashes for example during kernel debugging (e.g., you
73 will be able to flush the buffer cache to disk, reboot the system
74 immediately or dump some status information). A key for each of the
75 possible requests is provided.
76
77 This is the feature normally accomplished by pressing a key
78 while holding SysRq (Alt+PrintScreen).
79
80 On UML, this is accomplished by sending a "sysrq" command with
81 mconsole, followed by the letter for the requested command.
82
83 The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
84 unless you really know what this hack does.
85
86config KERNEL_STACK_ORDER
87 int "Kernel stack size order"
88 default 1 if 64BIT
89 range 1 10 if 64BIT
90 default 0 if !64BIT
91 help
92 This option determines the size of UML kernel stacks. They will
93 be 1 << order pages. The default is OK unless you're running Valgrind
94 on UML, in which case, set this to 3.
95
96config MMAPPER
97 tristate "iomem emulation driver"
98 help
99 This driver allows a host file to be used as emulated IO memory inside
100 UML.
101
102config NO_DMA
103 def_bool y
104
105config PGTABLE_LEVELS
106 int
107 default 3 if 3_LEVEL_PGTABLES
108 default 2
109
110config SECCOMP
111 def_bool y
112 prompt "Enable seccomp to safely compute untrusted bytecode"
113 ---help---
114 This kernel feature is useful for number crunching applications
115 that may need to compute untrusted bytecode during their
116 execution. By using pipes or other transports made available to
117 the process as file descriptors supporting the read/write
118 syscalls, it's possible to isolate those applications in
119 their own address space using seccomp. Once seccomp is
120 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
121 and the task is only allowed to execute a few safe syscalls
122 defined by each seccomp mode.
123
124 If unsure, say Y.