| rjw | 1f88458 | 2022-01-06 17:20:42 +0800 | [diff] [blame^] | 1 | # SPDX-License-Identifier: GPL-2.0 |
| 2 | config 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 | |
| 13 | source "mm/Kconfig" |
| 14 | |
| 15 | config LD_SCRIPT_STATIC |
| 16 | bool |
| 17 | default y |
| 18 | depends on STATIC_LINK |
| 19 | |
| 20 | config LD_SCRIPT_DYN |
| 21 | bool |
| 22 | default y |
| 23 | depends on !LD_SCRIPT_STATIC |
| 24 | select MODULE_REL_CRCS if MODVERSIONS |
| 25 | |
| 26 | source "fs/Kconfig.binfmt" |
| 27 | |
| 28 | config 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 | |
| 49 | config 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 | |
| 67 | config 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 | |
| 86 | config 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 | |
| 96 | config 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 | |
| 102 | config NO_DMA |
| 103 | def_bool y |
| 104 | |
| 105 | config PGTABLE_LEVELS |
| 106 | int |
| 107 | default 3 if 3_LEVEL_PGTABLES |
| 108 | default 2 |
| 109 | |
| 110 | config 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. |