Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Renove faith(4) and faithd(8) from base. It looks like industry
have chosen different (and more traditional) stateless/statuful
NAT64 as translation mechanism. Last non-trivial commits to both
faith(4) and faithd(8) happened more than 12 years ago, so I assume
it is time to drop RFC3142 in FreeBSD.

No objections from: net@

Back out r253779 & r253786.

Decouple yarrow from random(4) device.

* Make Yarrow an optional kernel component -- enabled by "YARROW_RNG" option.
The files sha2.c, hash.c, randomdev_soft.c and yarrow.c comprise yarrow.

* random(4) device doesn't really depend on rijndael-*. Yarrow, however, does.

* Add random_adaptors.[ch] which is basically a store of random_adaptor's.
random_adaptor is basically an adapter that plugs in to random(4).
random_adaptor can only be plugged in to random(4) very early in bootup.
Unplugging random_adaptor from random(4) is not supported, and is probably a
bad idea anyway, due to potential loss of entropy pools.
We currently have 3 random_adaptors:
+ yarrow
+ rdrand (ivy.c)
+ nehemeiah

* Remove platform dependent logic from probe.c, and move it into
corresponding registration routines of each random_adaptor provider.
probe.c doesn't do anything other than picking a specific random_adaptor
from a list of registered ones.

* If the kernel doesn't have any random_adaptor adapters present then the
creation of /dev/random is postponed until next random_adaptor is kldload'ed.

* Fix randomdev_soft.c to refer to its own random_adaptor, instead of a
system wide one.

Submitted by: arthurmesh@gmail.com, obrien
Obtained from: Juniper Networks
Reviewed by: obrien

Add basic SMP support for GXemul. Ideally we would have some way to override
some of the IPI mechanisms used by the common MIPS SMP code so we could use
the multicast IPI facilities, on GXemul as well as on several real hardware
platforms, and the ability to have multiple hard IPI types.

Add a trivial driver for the GXemul Ethernet device. Probably quite buggy and
certainly non-optimal, but enough for basic networking use.

Requested by: rwatson

Add a driver for the GXemul test machine's disk controller and disk devices.
Prefer it to using an md device in the GXEMUL kernel configuration.

Requested by: rwatson, theraven

mips/mips64eb became mips/mips64 while I wasn't looking (whoops), so update
GXEMUL kernel config for the new world order.

Spotted by: bz
MFC after: 3 weeks

Merge a rudimentary gxemul "oldtestmips" port. This consists almost
entirely of one machdep file lifted from the MALTA port, as well as
a low-level console and tty driver for the gxemul debugging console
device (the emulators stdio). As with many low-level embedded and
hypervisor console devices, it is polled only, so we drive TTY I/O
from a callout; we are perhaps a bit too aware of the MIPS physical
maps in order to attach the console before newbus comes to life.

The sample kernel configuration depends on an MD-based root file
system, which is not provided. However, any 64-bit, big-endian
userspace image (such as one generated for MALTA) should work.

This will hopefully be supplemented by additional device drivers for
gxemul-specific hardware simulations from Juli Mallett. We have
found oldtestmips quite useful for testing and improving aspects of
the MIPS port, so it's worth supporting better in FreeBSD.

Requested by: theraven, jmallett
Sponsored by: DARPA, AFRL
MFC after: 3 weeks