xref: /openbmc/linux/fs/Kconfig.binfmt (revision b830f94f)
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 ARCH_HAS_BINFMT_FLAT
95	bool
96
97config BINFMT_FLAT
98	bool "Kernel support for flat binaries"
99	depends on ARCH_HAS_BINFMT_FLAT
100	help
101	  Support uClinux FLAT format binaries.
102
103config BINFMT_FLAT_ARGVP_ENVP_ON_STACK
104	bool
105
106config BINFMT_FLAT_OLD_ALWAYS_RAM
107	bool
108
109config BINFMT_FLAT_OLD
110	bool "Enable support for very old legacy flat binaries"
111	depends on BINFMT_FLAT
112	help
113	  Support decade old uClinux FLAT format binaries.  Unless you know
114	  you have some of those say N here.
115
116config BINFMT_ZFLAT
117	bool "Enable ZFLAT support"
118	depends on BINFMT_FLAT
119	select ZLIB_INFLATE
120	help
121	  Support FLAT format compressed binaries
122
123config BINFMT_SHARED_FLAT
124	bool "Enable shared FLAT support"
125	depends on BINFMT_FLAT
126	help
127	  Support FLAT shared libraries
128
129config HAVE_AOUT
130       def_bool n
131
132config BINFMT_AOUT
133	tristate "Kernel support for a.out and ECOFF binaries"
134	depends on HAVE_AOUT
135	---help---
136	  A.out (Assembler.OUTput) is a set of formats for libraries and
137	  executables used in the earliest versions of UNIX.  Linux used
138	  the a.out formats QMAGIC and ZMAGIC until they were replaced
139	  with the ELF format.
140
141	  The conversion to ELF started in 1995.  This option is primarily
142	  provided for historical interest and for the benefit of those
143	  who need to run binaries from that era.
144
145	  Most people should answer N here.  If you think you may have
146	  occasional use for this format, enable module support above
147	  and answer M here to compile this support as a module called
148	  binfmt_aout.
149
150	  If any crucial components of your system (such as /sbin/init
151	  or /lib/ld.so) are still in a.out format, you will have to
152	  say Y here.
153
154config OSF4_COMPAT
155	bool "OSF/1 v4 readv/writev compatibility"
156	depends on ALPHA && BINFMT_AOUT
157	help
158	  Say Y if you are using OSF/1 binaries (like Netscape and Acrobat)
159	  with v4 shared libraries freely available from Compaq. If you're
160	  going to use shared libraries from Tru64 version 5.0 or later, say N.
161
162config BINFMT_EM86
163	tristate "Kernel support for Linux/Intel ELF binaries"
164	depends on ALPHA
165	---help---
166	  Say Y here if you want to be able to execute Linux/Intel ELF
167	  binaries just like native Alpha binaries on your Alpha machine. For
168	  this to work, you need to have the emulator /usr/bin/em86 in place.
169
170	  You can get the same functionality by saying N here and saying Y to
171	  "Kernel support for MISC binaries".
172
173	  You may answer M to compile the emulation support as a module and
174	  later load the module when you want to use a Linux/Intel binary. The
175	  module will be called binfmt_em86. If unsure, say Y.
176
177config BINFMT_MISC
178	tristate "Kernel support for MISC binaries"
179	---help---
180	  If you say Y here, it will be possible to plug wrapper-driven binary
181	  formats into the kernel. You will like this especially when you use
182	  programs that need an interpreter to run like Java, Python, .NET or
183	  Emacs-Lisp. It's also useful if you often run DOS executables under
184	  the Linux DOS emulator DOSEMU (read the DOSEMU-HOWTO, available from
185	  <http://www.tldp.org/docs.html#howto>). Once you have
186	  registered such a binary class with the kernel, you can start one of
187	  those programs simply by typing in its name at a shell prompt; Linux
188	  will automatically feed it to the correct interpreter.
189
190	  You can do other nice things, too. Read the file
191	  <file:Documentation/admin-guide/binfmt-misc.rst> to learn how to use this
192	  feature, <file:Documentation/admin-guide/java.rst> for information about how
193	  to include Java support. and <file:Documentation/admin-guide/mono.rst> for
194          information about how to include Mono-based .NET support.
195
196          To use binfmt_misc, you will need to mount it:
197		mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc
198
199	  You may say M here for module support and later load the module when
200	  you have use for it; the module is called binfmt_misc. If you
201	  don't know what to answer at this point, say Y.
202
203config COREDUMP
204	bool "Enable core dump support" if EXPERT
205	default y
206	help
207	  This option enables support for performing core dumps. You almost
208	  certainly want to say Y here. Not necessary on systems that never
209	  need debugging or only ever run flawless code.
210
211endmenu
212