xref: /linux/fs/Kconfig.binfmt (revision b7019ac550eb3916f34d79db583e9b7ea2524afa)
1# SPDX-License-Identifier: GPL-2.0-only
2
3menu "Executable file formats"
4
5config BINFMT_ELF
6	bool "Kernel support for ELF binaries"
7	depends on MMU
8	select ELFCORE
9	default y
10	---help---
11	  ELF (Executable and Linkable Format) is a format for libraries and
12	  executables used across different architectures and operating
13	  systems. Saying Y here will enable your kernel to run ELF binaries
14	  and enlarge it by about 13 KB. ELF support under Linux has now all
15	  but replaced the traditional Linux a.out formats (QMAGIC and ZMAGIC)
16	  because it is portable (this does *not* mean that you will be able
17	  to run executables from different architectures or operating systems
18	  however) and makes building run-time libraries very easy. Many new
19	  executables are distributed solely in ELF format. You definitely
20	  want to say Y here.
21
22	  Information about ELF is contained in the ELF HOWTO available from
23	  <http://www.tldp.org/docs.html#howto>.
24
25	  If you find that after upgrading from Linux kernel 1.2 and saying Y
26	  here, you still can't run any ELF binaries (they just crash), then
27	  you'll have to install the newest ELF runtime libraries, including
28	  ld.so (check the file <file:Documentation/Changes> for location and
29	  latest version).
30
31config COMPAT_BINFMT_ELF
32	bool
33	depends on COMPAT && BINFMT_ELF
34	select ELFCORE
35
36config ARCH_BINFMT_ELF_STATE
37	bool
38
39config BINFMT_ELF_FDPIC
40	bool "Kernel support for FDPIC ELF binaries"
41	default y if !BINFMT_ELF
42	depends on (ARM || (SUPERH32 && !MMU) || C6X)
43	select ELFCORE
44	help
45	  ELF FDPIC binaries are based on ELF, but allow the individual load
46	  segments of a binary to be located in memory independently of each
47	  other. This makes this format ideal for use in environments where no
48	  MMU is available as it still permits text segments to be shared,
49	  even if data segments are not.
50
51	  It is also possible to run FDPIC ELF binaries on MMU linux also.
52
53config ELFCORE
54	bool
55	help
56	  This option enables kernel/elfcore.o.
57
58config CORE_DUMP_DEFAULT_ELF_HEADERS
59	bool "Write ELF core dumps with partial segments"
60	default y
61	depends on BINFMT_ELF && ELF_CORE
62	help
63	  ELF core dump files describe each memory mapping of the crashed
64	  process, and can contain or omit the memory contents of each one.
65	  The contents of an unmodified text mapping are omitted by default.
66
67	  For an unmodified text mapping of an ELF object, including just
68	  the first page of the file in a core dump makes it possible to
69	  identify the build ID bits in the file, without paying the i/o
70	  cost and disk space to dump all the text.  However, versions of
71	  GDB before 6.7 are confused by ELF core dump files in this format.
72
73	  The core dump behavior can be controlled per process using
74	  the /proc/PID/coredump_filter pseudo-file; this setting is
75	  inherited.  See Documentation/filesystems/proc.txt for details.
76
77	  This config option changes the default setting of coredump_filter
78	  seen at boot time.  If unsure, say Y.
79
80config BINFMT_SCRIPT
81	tristate "Kernel support for scripts starting with #!"
82	default y
83	help
84	  Say Y here if you want to execute interpreted scripts starting with
85	  #! followed by the path to an interpreter.
86
87	  You can build this support as a module; however, until that module
88	  gets loaded, you cannot run scripts.  Thus, if you want to load this
89	  module from an initramfs, the portion of the initramfs before loading
90	  this module must consist of compiled binaries only.
91
92	  Most systems will not boot if you say M or N here.  If unsure, say Y.
93
94config BINFMT_FLAT
95	bool "Kernel support for flat binaries"
96	depends on !MMU || ARM || M68K
97	help
98	  Support uClinux FLAT format binaries.
99
100config BINFMT_ZFLAT
101	bool "Enable ZFLAT support"
102	depends on BINFMT_FLAT
103	select ZLIB_INFLATE
104	help
105	  Support FLAT format compressed binaries
106
107config BINFMT_SHARED_FLAT
108	bool "Enable shared FLAT support"
109	depends on BINFMT_FLAT
110	help
111	  Support FLAT shared libraries
112
113config HAVE_AOUT
114       def_bool n
115
116config BINFMT_AOUT
117	tristate "Kernel support for a.out and ECOFF binaries"
118	depends on HAVE_AOUT
119	---help---
120	  A.out (Assembler.OUTput) is a set of formats for libraries and
121	  executables used in the earliest versions of UNIX.  Linux used
122	  the a.out formats QMAGIC and ZMAGIC until they were replaced
123	  with the ELF format.
124
125	  The conversion to ELF started in 1995.  This option is primarily
126	  provided for historical interest and for the benefit of those
127	  who need to run binaries from that era.
128
129	  Most people should answer N here.  If you think you may have
130	  occasional use for this format, enable module support above
131	  and answer M here to compile this support as a module called
132	  binfmt_aout.
133
134	  If any crucial components of your system (such as /sbin/init
135	  or /lib/ld.so) are still in a.out format, you will have to
136	  say Y here.
137
138config OSF4_COMPAT
139	bool "OSF/1 v4 readv/writev compatibility"
140	depends on ALPHA && BINFMT_AOUT
141	help
142	  Say Y if you are using OSF/1 binaries (like Netscape and Acrobat)
143	  with v4 shared libraries freely available from Compaq. If you're
144	  going to use shared libraries from Tru64 version 5.0 or later, say N.
145
146config BINFMT_EM86
147	tristate "Kernel support for Linux/Intel ELF binaries"
148	depends on ALPHA
149	---help---
150	  Say Y here if you want to be able to execute Linux/Intel ELF
151	  binaries just like native Alpha binaries on your Alpha machine. For
152	  this to work, you need to have the emulator /usr/bin/em86 in place.
153
154	  You can get the same functionality by saying N here and saying Y to
155	  "Kernel support for MISC binaries".
156
157	  You may answer M to compile the emulation support as a module and
158	  later load the module when you want to use a Linux/Intel binary. The
159	  module will be called binfmt_em86. If unsure, say Y.
160
161config BINFMT_MISC
162	tristate "Kernel support for MISC binaries"
163	---help---
164	  If you say Y here, it will be possible to plug wrapper-driven binary
165	  formats into the kernel. You will like this especially when you use
166	  programs that need an interpreter to run like Java, Python, .NET or
167	  Emacs-Lisp. It's also useful if you often run DOS executables under
168	  the Linux DOS emulator DOSEMU (read the DOSEMU-HOWTO, available from
169	  <http://www.tldp.org/docs.html#howto>). Once you have
170	  registered such a binary class with the kernel, you can start one of
171	  those programs simply by typing in its name at a shell prompt; Linux
172	  will automatically feed it to the correct interpreter.
173
174	  You can do other nice things, too. Read the file
175	  <file:Documentation/admin-guide/binfmt-misc.rst> to learn how to use this
176	  feature, <file:Documentation/admin-guide/java.rst> for information about how
177	  to include Java support. and <file:Documentation/admin-guide/mono.rst> for
178          information about how to include Mono-based .NET support.
179
180          To use binfmt_misc, you will need to mount it:
181		mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc
182
183	  You may say M here for module support and later load the module when
184	  you have use for it; the module is called binfmt_misc. If you
185	  don't know what to answer at this point, say Y.
186
187config COREDUMP
188	bool "Enable core dump support" if EXPERT
189	default y
190	help
191	  This option enables support for performing core dumps. You almost
192	  certainly want to say Y here. Not necessary on systems that never
193	  need debugging or only ever run flawless code.
194
195endmenu
196