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COMPAT_NETBSD32(8) NetBSD System Manager's Manual COMPAT_NETBSD32(8)
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by Kimmo Suominen.
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compat_netbsd32 -- setup procedure for 32-bit compatibility on 64-bit
The compat_netbsd32 module allows NetBSD/sparc64 to run NetBSD/sparc exe-
cutables, NetBSD/aarch64 to run NetBSD/arm executables, NetBSD/mips64 to
run NetBSD/mips executables, and NetBSD/amd64 to run NetBSD/i386 executa-
bles. On NetBSD/mips64 the default userland is N32 which is a handled by
compat_netbsd32 framework, and 64-bit binaries are handled similarly to
the setup for 32-bit compatibility. It also provides compatibility
between OABI and EABI binaries on 32-bit NetBSD/arm ports.
To use compat_netbsd32, one must either have COMPAT_NETBSD32 and
EXEC_ELF32 in the kernel, or load the compat_netbsd32 and exec_elf32 ker-
Static executables typically need no additional setup. Dynamic binaries
require the dynamic linker plus shared libraries.
Since NetBSD 5.0 the base system has directly included support for 32-bit
compatibility by installing 32-bit libraries and dynamic linker into
/usr. This includes compiler support for compiling 32-bit applications
on platforms where this is supported.
For a.out compatibility, /usr/libexec/ld.so from a 32-bit distribution is
required to exist, and the a.out shared libraries must be found in
/emul/aout as normal for a.out compatibility. For 32-bit (64-bit on
NetBSD/mips64) ELF compatibility, the relevant /usr/libexec/ld.elf_so
needs to be found in
Port Target Path
amd64 i386 /usr/libexec/ld.elf_so-i386
sparc64 sparc /usr/libexec/ld.elf_so-sparc
mips64 O32 /usr/libexec/ld.elf_so-o32
mips64 N64 /usr/libexec/ld.elf_so-64
powerpc64 powerpc /usr/libexec/ld.elf_so-powerpc
arm64 eabi /usr/libexec/ld.elf_so-eabi
Note that the kernel handles rewriting the builting ELF interpreter to
the above path.
Before NetBSD 5.0 all of these files needed to be placed under
The shared libraries for a.out binaries do not live under the
/emul/netbsd32 directory, but under the /emul/aout directory, where the
a.out dynamic linker will find them.
A list of things which fail to work in compatibility mode should be here.
aio(3) is not supported.
Some ioctl(2) commands are not supported, including drm(4).
NetBSD 9.3 January 17, 2019 NetBSD 9.3