xref: /openbmc/linux/fs/Kconfig.binfmt (revision 9549fb35)
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 BINFMT_ELF_KUNIT_TEST
32	bool "Build KUnit tests for ELF binary support" if !KUNIT_ALL_TESTS
33	depends on KUNIT=y && BINFMT_ELF=y
34	default KUNIT_ALL_TESTS
35	help
36	  This builds the ELF loader KUnit tests, which try to gather
37	  prior bug fixes into a regression test collection. This is really
38	  only needed for debugging. Note that with CONFIG_COMPAT=y, the
39	  compat_binfmt_elf KUnit test is also created.
40
41config COMPAT_BINFMT_ELF
42	def_bool y
43	depends on COMPAT && BINFMT_ELF
44	select ELFCORE
45
46config ARCH_BINFMT_ELF_STATE
47	bool
48
49config ARCH_BINFMT_ELF_EXTRA_PHDRS
50	bool
51
52config ARCH_HAVE_ELF_PROT
53	bool
54
55config ARCH_USE_GNU_PROPERTY
56	bool
57
58config BINFMT_ELF_FDPIC
59	bool "Kernel support for FDPIC ELF binaries"
60	default y if !BINFMT_ELF
61	depends on ARM || ((M68K || RISCV || SUPERH || XTENSA) && !MMU)
62	select ELFCORE
63	help
64	  ELF FDPIC binaries are based on ELF, but allow the individual load
65	  segments of a binary to be located in memory independently of each
66	  other. This makes this format ideal for use in environments where no
67	  MMU is available as it still permits text segments to be shared,
68	  even if data segments are not.
69
70	  It is also possible to run FDPIC ELF binaries on MMU linux also.
71
72config ELFCORE
73	bool
74	help
75	  This option enables kernel/elfcore.o.
76
77config CORE_DUMP_DEFAULT_ELF_HEADERS
78	bool "Write ELF core dumps with partial segments"
79	default y
80	depends on BINFMT_ELF && ELF_CORE
81	help
82	  ELF core dump files describe each memory mapping of the crashed
83	  process, and can contain or omit the memory contents of each one.
84	  The contents of an unmodified text mapping are omitted by default.
85
86	  For an unmodified text mapping of an ELF object, including just
87	  the first page of the file in a core dump makes it possible to
88	  identify the build ID bits in the file, without paying the i/o
89	  cost and disk space to dump all the text.  However, versions of
90	  GDB before 6.7 are confused by ELF core dump files in this format.
91
92	  The core dump behavior can be controlled per process using
93	  the /proc/PID/coredump_filter pseudo-file; this setting is
94	  inherited.  See Documentation/filesystems/proc.rst for details.
95
96	  This config option changes the default setting of coredump_filter
97	  seen at boot time.  If unsure, say Y.
98
99config BINFMT_SCRIPT
100	tristate "Kernel support for scripts starting with #!"
101	default y
102	help
103	  Say Y here if you want to execute interpreted scripts starting with
104	  #! followed by the path to an interpreter.
105
106	  You can build this support as a module; however, until that module
107	  gets loaded, you cannot run scripts.  Thus, if you want to load this
108	  module from an initramfs, the portion of the initramfs before loading
109	  this module must consist of compiled binaries only.
110
111	  Most systems will not boot if you say M or N here.  If unsure, say Y.
112
113config ARCH_HAS_BINFMT_FLAT
114	bool
115
116config BINFMT_FLAT
117	bool "Kernel support for flat binaries"
118	depends on ARCH_HAS_BINFMT_FLAT
119	help
120	  Support uClinux FLAT format binaries.
121
122config BINFMT_FLAT_ARGVP_ENVP_ON_STACK
123	bool
124
125config BINFMT_FLAT_OLD_ALWAYS_RAM
126	bool
127
128config BINFMT_FLAT_NO_DATA_START_OFFSET
129	bool
130
131config BINFMT_FLAT_OLD
132	bool "Enable support for very old legacy flat binaries"
133	depends on BINFMT_FLAT
134	help
135	  Support decade old uClinux FLAT format binaries.  Unless you know
136	  you have some of those say N here.
137
138config BINFMT_ZFLAT
139	bool "Enable ZFLAT support"
140	depends on BINFMT_FLAT
141	select ZLIB_INFLATE
142	help
143	  Support FLAT format compressed binaries
144
145config BINFMT_MISC
146	tristate "Kernel support for MISC binaries"
147	help
148	  If you say Y here, it will be possible to plug wrapper-driven binary
149	  formats into the kernel. You will like this especially when you use
150	  programs that need an interpreter to run like Java, Python, .NET or
151	  Emacs-Lisp. It's also useful if you often run DOS executables under
152	  the Linux DOS emulator DOSEMU (read the DOSEMU-HOWTO, available from
153	  <http://www.tldp.org/docs.html#howto>). Once you have
154	  registered such a binary class with the kernel, you can start one of
155	  those programs simply by typing in its name at a shell prompt; Linux
156	  will automatically feed it to the correct interpreter.
157
158	  You can do other nice things, too. Read the file
159	  <file:Documentation/admin-guide/binfmt-misc.rst> to learn how to use this
160	  feature, <file:Documentation/admin-guide/java.rst> for information about how
161	  to include Java support. and <file:Documentation/admin-guide/mono.rst> for
162          information about how to include Mono-based .NET support.
163
164          To use binfmt_misc, you will need to mount it:
165		mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc
166
167	  You may say M here for module support and later load the module when
168	  you have use for it; the module is called binfmt_misc. If you
169	  don't know what to answer at this point, say Y.
170
171config COREDUMP
172	bool "Enable core dump support" if EXPERT
173	default y
174	help
175	  This option enables support for performing core dumps. You almost
176	  certainly want to say Y here. Not necessary on systems that never
177	  need debugging or only ever run flawless code.
178
179endmenu
180