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1config STATIC_LINK
2 bool "Force a static link"
3 default n
1da177e4 4 help
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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.
1da177e4 11
3f22ab27 12source "mm/Kconfig"
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13
14config LD_SCRIPT_STATIC
15 bool
16 default y
42fda663 17 depends on STATIC_LINK
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18
19config LD_SCRIPT_DYN
20 bool
21 default y
22 depends on !LD_SCRIPT_STATIC
23
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24source "fs/Kconfig.binfmt"
25
26config HOSTFS
27 tristate "Host filesystem"
28 help
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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:
1da177e4 34
4c9e1385 35 mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
1da177e4 36
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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.
1da177e4 40
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41 For more information, see
42 <http://user-mode-linux.sourceforge.net/hostfs.html>.
1da177e4 43
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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.
1da177e4 46
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47config MCONSOLE
48 bool "Management console"
1eb7c6c7 49 depends on PROC_FS
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50 default y
51 help
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52 The user mode linux management console is a low-level interface to
53 the kernel, somewhat like the i386 SysRq interface. Since there is
54 a full-blown operating system running under every user mode linux
55 instance, there is much greater flexibility possible than with the
56 SysRq mechanism.
1da177e4 57
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58 If you answer 'Y' to this option, to use this feature, you need the
59 mconsole client (called uml_mconsole) which is present in CVS in
60 2.4.5-9um and later (path /tools/mconsole), and is also in the
61 distribution RPM package in 2.4.6 and later.
1da177e4 62
4c9e1385 63 It is safe to say 'Y' here.
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64
65config MAGIC_SYSRQ
66 bool "Magic SysRq key"
67 depends on MCONSOLE
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68 help
69 If you say Y here, you will have some control over the system even
70 if the system crashes for example during kernel debugging (e.g., you
71 will be able to flush the buffer cache to disk, reboot the system
72 immediately or dump some status information). A key for each of the
73 possible requests is provided.
1da177e4 74
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75 This is the feature normally accomplished by pressing a key
76 while holding SysRq (Alt+PrintScreen).
1da177e4 77
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78 On UML, this is accomplished by sending a "sysrq" command with
79 mconsole, followed by the letter for the requested command.
1da177e4 80
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81 The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
82 unless you really know what this hack does.
1da177e4 83
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84config KERNEL_STACK_ORDER
85 int "Kernel stack size order"
02239c29 86 default 1 if 64BIT
e80ad9b6 87 range 1 10 if 64BIT
02239c29 88 default 0 if !64BIT
1da177e4 89 help
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90 This option determines the size of UML kernel stacks. They will
91 be 1 << order pages. The default is OK unless you're running Valgrind
92 on UML, in which case, set this to 3.
d911202e 93
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94config MMAPPER
95 tristate "iomem emulation driver"
96 help
97 This driver allows a host file to be used as emulated IO memory inside
98 UML.
99
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100config NO_DMA
101 def_bool y
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102
103config PGTABLE_LEVELS
104 int
105 default 3 if 3_LEVEL_PGTABLES
106 default 2
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107
108config SECCOMP
109 def_bool y
110 prompt "Enable seccomp to safely compute untrusted bytecode"
111 ---help---
112 This kernel feature is useful for number crunching applications
113 that may need to compute untrusted bytecode during their
114 execution. By using pipes or other transports made available to
115 the process as file descriptors supporting the read/write
116 syscalls, it's possible to isolate those applications in
117 their own address space using seccomp. Once seccomp is
118 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
119 and the task is only allowed to execute a few safe syscalls
120 defined by each seccomp mode.
121
122 If unsure, say Y.