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![David Hildenbrand](/assets/img/avatar_default.png)
We have a fairly specific alpha binary loader in Linux: running x86 (i386, i486) binaries via the em86 [1] emulator. As noted in the Kconfig option, the same behavior can be achieved via binfmt_misc, for example, more nowadays used for running qemu-user. An example on how to get binfmt_misc running with em86 can be found in Documentation/admin-guide/binfmt-misc.rst The defconfig does not have CONFIG_BINFMT_EM86=y set. And doing a make defconfig && make olddefconfig results in # CONFIG_BINFMT_EM86 is not set ... as we don't seem to have any supported Linux distirbution for alpha anymore, there isn't really any "default" user of that feature anymore. Searching for "CONFIG_BINFMT_EM86=y" reveals mostly discussions from around 20 years ago, like [2] describing how to get netscape via em86 running via em86, or [3] discussing that running wine or installing Win 3.11 through em86 would be a nice feature. The latest binaries available for em86 are from 2000, version 2.2.1 [4] -- which translates to "unsupported"; further, em86 doesn't even work with glibc-2.x but only with glibc-2.0 [4, 5]. These are clear signs that there might not be too many em86 users out there, especially users relying on modern Linux kernels. Even though the code footprint is relatively small, let's just get rid of this blast from the past that's effectively unused. [1] http://ftp.dreamtime.org/pub/linux/Linux-Alpha/em86/v0.4/docs/em86.html [2] https://static.lwn.net/1998/1119/a/alpha-netscape.html [3] https://groups.google.com/g/linux.debian.alpha/c/AkGuQHeCe0Y [4] http://zeniv.linux.org.uk/pub/linux/alpha/em86/v2.2-1/relnotes.2.2.1.html [5] https://forum.teamspeak.com/archive/index.php/t-1477.html Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-fsdevel@vger.kernel.org Cc: linux-api@vger.kernel.org Cc: linux-alpha@vger.kernel.org Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Matt Turner <mattst88@gmail.com>
205 lines
7 KiB
Text
205 lines
7 KiB
Text
# SPDX-License-Identifier: GPL-2.0-only
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menu "Executable file formats"
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config BINFMT_ELF
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bool "Kernel support for ELF binaries"
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depends on MMU
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select ELFCORE
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default y
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help
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ELF (Executable and Linkable Format) is a format for libraries and
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executables used across different architectures and operating
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systems. Saying Y here will enable your kernel to run ELF binaries
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and enlarge it by about 13 KB. ELF support under Linux has now all
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but replaced the traditional Linux a.out formats (QMAGIC and ZMAGIC)
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because it is portable (this does *not* mean that you will be able
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to run executables from different architectures or operating systems
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however) and makes building run-time libraries very easy. Many new
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executables are distributed solely in ELF format. You definitely
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want to say Y here.
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Information about ELF is contained in the ELF HOWTO available from
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<http://www.tldp.org/docs.html#howto>.
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If you find that after upgrading from Linux kernel 1.2 and saying Y
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here, you still can't run any ELF binaries (they just crash), then
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you'll have to install the newest ELF runtime libraries, including
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ld.so (check the file <file:Documentation/Changes> for location and
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latest version).
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config COMPAT_BINFMT_ELF
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def_bool y
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depends on COMPAT && BINFMT_ELF
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select ELFCORE
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config ARCH_BINFMT_ELF_STATE
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bool
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config ARCH_HAVE_ELF_PROT
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bool
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config ARCH_USE_GNU_PROPERTY
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bool
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config BINFMT_ELF_FDPIC
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bool "Kernel support for FDPIC ELF binaries"
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default y if !BINFMT_ELF
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depends on (ARM || (SUPERH && !MMU))
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select ELFCORE
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help
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ELF FDPIC binaries are based on ELF, but allow the individual load
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segments of a binary to be located in memory independently of each
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other. This makes this format ideal for use in environments where no
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MMU is available as it still permits text segments to be shared,
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even if data segments are not.
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It is also possible to run FDPIC ELF binaries on MMU linux also.
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config ELFCORE
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bool
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help
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This option enables kernel/elfcore.o.
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config CORE_DUMP_DEFAULT_ELF_HEADERS
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bool "Write ELF core dumps with partial segments"
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default y
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depends on BINFMT_ELF && ELF_CORE
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help
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ELF core dump files describe each memory mapping of the crashed
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process, and can contain or omit the memory contents of each one.
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The contents of an unmodified text mapping are omitted by default.
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For an unmodified text mapping of an ELF object, including just
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the first page of the file in a core dump makes it possible to
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identify the build ID bits in the file, without paying the i/o
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cost and disk space to dump all the text. However, versions of
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GDB before 6.7 are confused by ELF core dump files in this format.
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The core dump behavior can be controlled per process using
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the /proc/PID/coredump_filter pseudo-file; this setting is
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inherited. See Documentation/filesystems/proc.rst for details.
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This config option changes the default setting of coredump_filter
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seen at boot time. If unsure, say Y.
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config BINFMT_SCRIPT
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tristate "Kernel support for scripts starting with #!"
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default y
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help
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Say Y here if you want to execute interpreted scripts starting with
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#! followed by the path to an interpreter.
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You can build this support as a module; however, until that module
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gets loaded, you cannot run scripts. Thus, if you want to load this
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module from an initramfs, the portion of the initramfs before loading
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this module must consist of compiled binaries only.
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Most systems will not boot if you say M or N here. If unsure, say Y.
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config ARCH_HAS_BINFMT_FLAT
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bool
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config BINFMT_FLAT
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bool "Kernel support for flat binaries"
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depends on ARCH_HAS_BINFMT_FLAT
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help
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Support uClinux FLAT format binaries.
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config BINFMT_FLAT_ARGVP_ENVP_ON_STACK
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bool
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config BINFMT_FLAT_OLD_ALWAYS_RAM
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bool
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config BINFMT_FLAT_NO_DATA_START_OFFSET
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bool
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config BINFMT_FLAT_OLD
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bool "Enable support for very old legacy flat binaries"
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depends on BINFMT_FLAT
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help
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Support decade old uClinux FLAT format binaries. Unless you know
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you have some of those say N here.
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config BINFMT_ZFLAT
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bool "Enable ZFLAT support"
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depends on BINFMT_FLAT
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select ZLIB_INFLATE
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help
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Support FLAT format compressed binaries
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config BINFMT_SHARED_FLAT
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bool "Enable shared FLAT support"
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depends on BINFMT_FLAT
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help
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Support FLAT shared libraries
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config HAVE_AOUT
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def_bool n
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config BINFMT_AOUT
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tristate "Kernel support for a.out and ECOFF binaries"
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depends on HAVE_AOUT
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help
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A.out (Assembler.OUTput) is a set of formats for libraries and
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executables used in the earliest versions of UNIX. Linux used
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the a.out formats QMAGIC and ZMAGIC until they were replaced
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with the ELF format.
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The conversion to ELF started in 1995. This option is primarily
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provided for historical interest and for the benefit of those
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who need to run binaries from that era.
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Most people should answer N here. If you think you may have
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occasional use for this format, enable module support above
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and answer M here to compile this support as a module called
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binfmt_aout.
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If any crucial components of your system (such as /sbin/init
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or /lib/ld.so) are still in a.out format, you will have to
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say Y here.
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config OSF4_COMPAT
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bool "OSF/1 v4 readv/writev compatibility"
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depends on ALPHA && BINFMT_AOUT
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help
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Say Y if you are using OSF/1 binaries (like Netscape and Acrobat)
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with v4 shared libraries freely available from Compaq. If you're
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going to use shared libraries from Tru64 version 5.0 or later, say N.
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config BINFMT_MISC
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tristate "Kernel support for MISC binaries"
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help
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If you say Y here, it will be possible to plug wrapper-driven binary
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formats into the kernel. You will like this especially when you use
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programs that need an interpreter to run like Java, Python, .NET or
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Emacs-Lisp. It's also useful if you often run DOS executables under
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the Linux DOS emulator DOSEMU (read the DOSEMU-HOWTO, available from
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<http://www.tldp.org/docs.html#howto>). Once you have
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registered such a binary class with the kernel, you can start one of
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those programs simply by typing in its name at a shell prompt; Linux
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will automatically feed it to the correct interpreter.
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You can do other nice things, too. Read the file
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<file:Documentation/admin-guide/binfmt-misc.rst> to learn how to use this
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feature, <file:Documentation/admin-guide/java.rst> for information about how
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to include Java support. and <file:Documentation/admin-guide/mono.rst> for
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information about how to include Mono-based .NET support.
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To use binfmt_misc, you will need to mount it:
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mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc
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You may say M here for module support and later load the module when
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you have use for it; the module is called binfmt_misc. If you
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don't know what to answer at this point, say Y.
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config COREDUMP
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bool "Enable core dump support" if EXPERT
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default y
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help
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This option enables support for performing core dumps. You almost
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certainly want to say Y here. Not necessary on systems that never
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need debugging or only ever run flawless code.
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endmenu
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