xref: /openbmc/linux/fs/Kconfig.binfmt (revision 2cf1c348)
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	def_bool y
33	depends on COMPAT && BINFMT_ELF
34	select ELFCORE
35
36config ARCH_BINFMT_ELF_STATE
37	bool
38
39config ARCH_HAVE_ELF_PROT
40	bool
41
42config ARCH_USE_GNU_PROPERTY
43	bool
44
45config BINFMT_ELF_FDPIC
46	bool "Kernel support for FDPIC ELF binaries"
47	default y if !BINFMT_ELF
48	depends on (ARM || (SUPERH && !MMU))
49	select ELFCORE
50	help
51	  ELF FDPIC binaries are based on ELF, but allow the individual load
52	  segments of a binary to be located in memory independently of each
53	  other. This makes this format ideal for use in environments where no
54	  MMU is available as it still permits text segments to be shared,
55	  even if data segments are not.
56
57	  It is also possible to run FDPIC ELF binaries on MMU linux also.
58
59config ELFCORE
60	bool
61	help
62	  This option enables kernel/elfcore.o.
63
64config CORE_DUMP_DEFAULT_ELF_HEADERS
65	bool "Write ELF core dumps with partial segments"
66	default y
67	depends on BINFMT_ELF && ELF_CORE
68	help
69	  ELF core dump files describe each memory mapping of the crashed
70	  process, and can contain or omit the memory contents of each one.
71	  The contents of an unmodified text mapping are omitted by default.
72
73	  For an unmodified text mapping of an ELF object, including just
74	  the first page of the file in a core dump makes it possible to
75	  identify the build ID bits in the file, without paying the i/o
76	  cost and disk space to dump all the text.  However, versions of
77	  GDB before 6.7 are confused by ELF core dump files in this format.
78
79	  The core dump behavior can be controlled per process using
80	  the /proc/PID/coredump_filter pseudo-file; this setting is
81	  inherited.  See Documentation/filesystems/proc.rst for details.
82
83	  This config option changes the default setting of coredump_filter
84	  seen at boot time.  If unsure, say Y.
85
86config BINFMT_SCRIPT
87	tristate "Kernel support for scripts starting with #!"
88	default y
89	help
90	  Say Y here if you want to execute interpreted scripts starting with
91	  #! followed by the path to an interpreter.
92
93	  You can build this support as a module; however, until that module
94	  gets loaded, you cannot run scripts.  Thus, if you want to load this
95	  module from an initramfs, the portion of the initramfs before loading
96	  this module must consist of compiled binaries only.
97
98	  Most systems will not boot if you say M or N here.  If unsure, say Y.
99
100config ARCH_HAS_BINFMT_FLAT
101	bool
102
103config BINFMT_FLAT
104	bool "Kernel support for flat binaries"
105	depends on ARCH_HAS_BINFMT_FLAT
106	help
107	  Support uClinux FLAT format binaries.
108
109config BINFMT_FLAT_ARGVP_ENVP_ON_STACK
110	bool
111
112config BINFMT_FLAT_OLD_ALWAYS_RAM
113	bool
114
115config BINFMT_FLAT_NO_DATA_START_OFFSET
116	bool
117
118config BINFMT_FLAT_OLD
119	bool "Enable support for very old legacy flat binaries"
120	depends on BINFMT_FLAT
121	help
122	  Support decade old uClinux FLAT format binaries.  Unless you know
123	  you have some of those say N here.
124
125config BINFMT_ZFLAT
126	bool "Enable ZFLAT support"
127	depends on BINFMT_FLAT
128	select ZLIB_INFLATE
129	help
130	  Support FLAT format compressed binaries
131
132config BINFMT_SHARED_FLAT
133	bool "Enable shared FLAT support"
134	depends on BINFMT_FLAT
135	help
136	  Support FLAT shared libraries
137
138config HAVE_AOUT
139       def_bool n
140
141config BINFMT_AOUT
142	tristate "Kernel support for a.out and ECOFF binaries"
143	depends on HAVE_AOUT
144	help
145	  A.out (Assembler.OUTput) is a set of formats for libraries and
146	  executables used in the earliest versions of UNIX.  Linux used
147	  the a.out formats QMAGIC and ZMAGIC until they were replaced
148	  with the ELF format.
149
150	  The conversion to ELF started in 1995.  This option is primarily
151	  provided for historical interest and for the benefit of those
152	  who need to run binaries from that era.
153
154	  Most people should answer N here.  If you think you may have
155	  occasional use for this format, enable module support above
156	  and answer M here to compile this support as a module called
157	  binfmt_aout.
158
159	  If any crucial components of your system (such as /sbin/init
160	  or /lib/ld.so) are still in a.out format, you will have to
161	  say Y here.
162
163config OSF4_COMPAT
164	bool "OSF/1 v4 readv/writev compatibility"
165	depends on ALPHA && BINFMT_AOUT
166	help
167	  Say Y if you are using OSF/1 binaries (like Netscape and Acrobat)
168	  with v4 shared libraries freely available from Compaq. If you're
169	  going to use shared libraries from Tru64 version 5.0 or later, say N.
170
171config BINFMT_MISC
172	tristate "Kernel support for MISC binaries"
173	help
174	  If you say Y here, it will be possible to plug wrapper-driven binary
175	  formats into the kernel. You will like this especially when you use
176	  programs that need an interpreter to run like Java, Python, .NET or
177	  Emacs-Lisp. It's also useful if you often run DOS executables under
178	  the Linux DOS emulator DOSEMU (read the DOSEMU-HOWTO, available from
179	  <http://www.tldp.org/docs.html#howto>). Once you have
180	  registered such a binary class with the kernel, you can start one of
181	  those programs simply by typing in its name at a shell prompt; Linux
182	  will automatically feed it to the correct interpreter.
183
184	  You can do other nice things, too. Read the file
185	  <file:Documentation/admin-guide/binfmt-misc.rst> to learn how to use this
186	  feature, <file:Documentation/admin-guide/java.rst> for information about how
187	  to include Java support. and <file:Documentation/admin-guide/mono.rst> for
188          information about how to include Mono-based .NET support.
189
190          To use binfmt_misc, you will need to mount it:
191		mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc
192
193	  You may say M here for module support and later load the module when
194	  you have use for it; the module is called binfmt_misc. If you
195	  don't know what to answer at this point, say Y.
196
197config COREDUMP
198	bool "Enable core dump support" if EXPERT
199	default y
200	help
201	  This option enables support for performing core dumps. You almost
202	  certainly want to say Y here. Not necessary on systems that never
203	  need debugging or only ever run flawless code.
204
205endmenu
206