xref: /openbmc/linux/fs/Kconfig.binfmt (revision 9549fb35)

# SPDX-License-Identifier: GPL-2.0-only

menu "Executable file formats"

config BINFMT_ELF
	bool "Kernel support for ELF binaries"
	depends on MMU
	select ELFCORE
	default y
	help
	  ELF (Executable and Linkable Format) is a format for libraries and
	  executables used across different architectures and operating
	  systems. Saying Y here will enable your kernel to run ELF binaries
	  and enlarge it by about 13 KB. ELF support under Linux has now all
	  but replaced the traditional Linux a.out formats (QMAGIC and ZMAGIC)
	  because it is portable (this does *not* mean that you will be able
	  to run executables from different architectures or operating systems
	  however) and makes building run-time libraries very easy. Many new
	  executables are distributed solely in ELF format. You definitely
	  want to say Y here.

	  Information about ELF is contained in the ELF HOWTO available from
	  <http://www.tldp.org/docs.html#howto>.

	  If you find that after upgrading from Linux kernel 1.2 and saying Y
	  here, you still can't run any ELF binaries (they just crash), then
	  you'll have to install the newest ELF runtime libraries, including
	  ld.so (check the file <file:Documentation/Changes> for location and
	  latest version).

config BINFMT_ELF_KUNIT_TEST
	bool "Build KUnit tests for ELF binary support" if !KUNIT_ALL_TESTS
	depends on KUNIT=y && BINFMT_ELF=y
	default KUNIT_ALL_TESTS
	help
	  This builds the ELF loader KUnit tests, which try to gather
	  prior bug fixes into a regression test collection. This is really
	  only needed for debugging. Note that with CONFIG_COMPAT=y, the
	  compat_binfmt_elf KUnit test is also created.

config COMPAT_BINFMT_ELF
	def_bool y
	depends on COMPAT && BINFMT_ELF
	select ELFCORE

config ARCH_BINFMT_ELF_STATE
	bool

config ARCH_BINFMT_ELF_EXTRA_PHDRS
	bool

config ARCH_HAVE_ELF_PROT
	bool

config ARCH_USE_GNU_PROPERTY
	bool

config BINFMT_ELF_FDPIC
	bool "Kernel support for FDPIC ELF binaries"
	default y if !BINFMT_ELF
	depends on ARM || ((M68K || RISCV || SUPERH || XTENSA) && !MMU)
	select ELFCORE
	help
	  ELF FDPIC binaries are based on ELF, but allow the individual load
	  segments of a binary to be located in memory independently of each
	  other. This makes this format ideal for use in environments where no
	  MMU is available as it still permits text segments to be shared,
	  even if data segments are not.

	  It is also possible to run FDPIC ELF binaries on MMU linux also.

config ELFCORE
	bool
	help
	  This option enables kernel/elfcore.o.

config CORE_DUMP_DEFAULT_ELF_HEADERS
	bool "Write ELF core dumps with partial segments"
	default y
	depends on BINFMT_ELF && ELF_CORE
	help
	  ELF core dump files describe each memory mapping of the crashed
	  process, and can contain or omit the memory contents of each one.
	  The contents of an unmodified text mapping are omitted by default.

	  For an unmodified text mapping of an ELF object, including just
	  the first page of the file in a core dump makes it possible to
	  identify the build ID bits in the file, without paying the i/o
	  cost and disk space to dump all the text.  However, versions of
	  GDB before 6.7 are confused by ELF core dump files in this format.

	  The core dump behavior can be controlled per process using
	  the /proc/PID/coredump_filter pseudo-file; this setting is
	  inherited.  See Documentation/filesystems/proc.rst for details.

	  This config option changes the default setting of coredump_filter
	  seen at boot time.  If unsure, say Y.

config BINFMT_SCRIPT
	tristate "Kernel support for scripts starting with #!"
	default y
	help
	  Say Y here if you want to execute interpreted scripts starting with
	  #! followed by the path to an interpreter.

	  You can build this support as a module; however, until that module
	  gets loaded, you cannot run scripts.  Thus, if you want to load this
	  module from an initramfs, the portion of the initramfs before loading
	  this module must consist of compiled binaries only.

	  Most systems will not boot if you say M or N here.  If unsure, say Y.

config ARCH_HAS_BINFMT_FLAT
	bool

config BINFMT_FLAT
	bool "Kernel support for flat binaries"
	depends on ARCH_HAS_BINFMT_FLAT
	help
	  Support uClinux FLAT format binaries.

config BINFMT_FLAT_ARGVP_ENVP_ON_STACK
	bool

config BINFMT_FLAT_OLD_ALWAYS_RAM
	bool

config BINFMT_FLAT_NO_DATA_START_OFFSET
	bool

config BINFMT_FLAT_OLD
	bool "Enable support for very old legacy flat binaries"
	depends on BINFMT_FLAT
	help
	  Support decade old uClinux FLAT format binaries.  Unless you know
	  you have some of those say N here.

config BINFMT_ZFLAT
	bool "Enable ZFLAT support"
	depends on BINFMT_FLAT
	select ZLIB_INFLATE
	help
	  Support FLAT format compressed binaries

config BINFMT_MISC
	tristate "Kernel support for MISC binaries"
	help
	  If you say Y here, it will be possible to plug wrapper-driven binary
	  formats into the kernel. You will like this especially when you use
	  programs that need an interpreter to run like Java, Python, .NET or
	  Emacs-Lisp. It's also useful if you often run DOS executables under
	  the Linux DOS emulator DOSEMU (read the DOSEMU-HOWTO, available from
	  <http://www.tldp.org/docs.html#howto>). Once you have
	  registered such a binary class with the kernel, you can start one of
	  those programs simply by typing in its name at a shell prompt; Linux
	  will automatically feed it to the correct interpreter.

	  You can do other nice things, too. Read the file
	  <file:Documentation/admin-guide/binfmt-misc.rst> to learn how to use this
	  feature, <file:Documentation/admin-guide/java.rst> for information about how
	  to include Java support. and <file:Documentation/admin-guide/mono.rst> for
          information about how to include Mono-based .NET support.

          To use binfmt_misc, you will need to mount it:
		mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc

	  You may say M here for module support and later load the module when
	  you have use for it; the module is called binfmt_misc. If you
	  don't know what to answer at this point, say Y.

config COREDUMP
	bool "Enable core dump support" if EXPERT
	default y
	help
	  This option enables support for performing core dumps. You almost
	  certainly want to say Y here. Not necessary on systems that never
	  need debugging or only ever run flawless code.

endmenu