MFC r258259, r258798, r259010

Unify handling of illegal instruction faults between AIM and Book-E.

Make uart_cpu_powerpc work on both FDT and OFW systems.

Fix debug printfs in FPU_EMU to compile on powerpc64 and enable it for
powerpc64.

MFC r258247, r258250, r258257

Remove a pointless #ifdef AIM. This is just PPC64 specific, including
64-bit Book-E.

Make single precision floating point arithmetic actually work

Split the function of the PCB_FPU flags into two: PCB_FPU now indicates that
the actual FPU is enabled, while PCB_FPREGS indicates that the FPU state
structure in the PCB is valid.

MFC r258779,r258780,r258787,r258822:

Fix undefined behavior: (1 << 31) is not defined as 1 is an int and this
shifts into the sign bit. Instead use (1U << 31) which gets the
expected result.

Similar to the (1 << 31) case it is not defined to do (2 << 30).

This fix is not ideal as it assumes a 32 bit int, but does fix the issue
for most cases.

A similar change was made in OpenBSD.

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Mark all SYSCTL_NODEs static that have no corresponding SYSCTL_DECLs.

The SYSCTL_NODE macro defines a list that stores all child-elements of
that node. If there's no SYSCTL_DECL macro anywhere else, there's no
reason why it shouldn't be static.

The NetBSD Foundation has granted permission to remove clause 3 and 4 from
their software.

Obtained from: NetBSD

Include <sys/types.h> before <sys/systm.h> to get typedefs required
by new atomic.h. Fixes tinderbox LINT build.

Don't define DEBUG. No debugging required.

Pointy hat: marcel

Resolve warnings exposed by LINT.
o Put prototypes in a single header only.
o Fix printf format specifiers.

Add a floating-point emulator so that a single userland or single ABI
can run on processors that don't have a FPU. This is typically the
case for Book E processors. While a tuned system will probably want
to use soft-float (or use a processor that has a FPU if the usage is
FP intensive enough), allowing hard-float on FPU-less systems gives
great portability and flexibility.

Obtained from: NetBSD