This change adds an implementation of a sysent for running CloudABI
armv6 and armv7 binaries on FreeBSD/arm64. It is a somewhat literal copy
of the armv6 version, except that it's been patched up to use the proper
registers.
Just like for cloudabi32.ko on FreeBSD/amd64, we make use of a vDSO that
automatically pads system call parameters to 64-bit value. These are
stored in a buffer on the stack, meaning we need to use copyin() and
copyout() unconditionally.
Now that all of the necessary bits for ARMv6 support for CloudABI have
been checked in, let's hook the kernel module up to the build and
document its existence.
It turns out that it is pretty easy to make CloudABI work on ARM64. We
essentially only need to copy over the sysvec from AMD64 and ensure that
we use ARM64 specific registers.
As there is an overlap between function argument and return registers,
we do need to extend cloudabi64_schedtail() to only set its values if
we're actually forking. Not when we're creating a new thread.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D3917
CloudABI has two separate kernel modules: cloudabi and cloudabi64. The
first module contains all the pointer size independent code, whereas
cloudabi64 contains the actual 64-bits specific system calls and the ELF
loader.
Reviewed by: wblock
Obtained from: https://github.com/NuxiNL/freebsd
Differential Revision: https://reviews.freebsd.org/D3258
