sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

arm: Add support for using VFP in kernel

Add missing logic to allow in-kernel VFP usage for ARMv7 NEON.
The implementation is strongly based on arm64 code.
It introduces a family of fpu_kern_* functions to enable the usage
of VFP instructions in kernel.
Apart from that the existing armv7 VFP logic was modified,
taking into account that the state of the VFP registers can now
be modified in the kernel.

Co-developed by: Wojciech Macek <wma@FreeBSD.org>
Sponsored by: Stormshield
Obtained from: Semihalf
Reviewed by: andrew
Differential Revision: https://reviews.freebsd.org/D37419

arm: clean up empty lines in .c and .h files

sys/arm: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Cleanup structures related to VFP and/or mcontext_t.
- in mcontext_t, rename newer used 'union __vfp' to equaly sized 'mc_spare'.
Space allocated by 'union __vfp' is too small and cannot hold full
VFP context.
- move structures defined in fp.h to more appropriate headers.
- remove all unused VFP structures.

MFC after: 2 weeks

Make PCB structure binary compatible for old and new PMAP on ARM

This structure must be binary compatible regardless of PMAP
version being used. Create reserved section for NEW_PMAP to
make other variables be placed exactly in the same memory
addresses. This fixes kgdb/gdb behavoiur, which uses pcb.h stuctures.
The NEW_PMAP is kernel flag, so it does not propagate to the buildworld,
what makes the tools using pcb.h unable to parse PCB data.

Reviewed by: mmel, kib
Submitted by: Wojciech Macek <wma@semihalf.com>
Obtained from: Semihalf
Sponsored by: Juniper Networks Inc.
Differential Revision: https://reviews.freebsd.org/D4011

ARM: Remove trailing whitespace from sys/arm/include
No functional changes.

Approved by: kib (mentor)

New pmap code for armv6. Disabled by default, option ARM_NEW_PMAP enables it.

This is pretty much a complete rewrite based on the existing i386 code. The
patches have been circulating for a couple years and have been looked at by
plenty of people, but I'm not putting anybody on the hook as having reviewed
this in any formal sense except myself.

After this has gotten wider testing from the user community, ARM_NEW_PMAP
will become the default and various dregs of the old pmap code will be
removed.

Submitted by: Svatopluk Kraus <onwahe@gmail.com>,
Michal Meloun <meloun@miracle.cz>

Cleanup up ARM *frame structures...

- Eliminate unused irqframe
- Eliminate unused saframe
- Instead of splitting r4-sp storage between the stack and switchframe,
just put all the registers in switchframe and eliminate the un_32 struct.

Submitted by: Svatopluk Kraus <onwahe@gmail.com>,
Michal Meloun <meloun@miracle.cz>

Remove all dregs of a per-thread undefined-exception-mode stack. This is
a leftover from the days when a low-level debugger had hooks in the
undefined exception vector and needed stack space to function. These days
it effectively isn't used because we switch immediately to the svc32 mode
stack on exception entry. For that, the single undef mode stack per core
that gets set up at init time works fine.

The stack wasn't necessary but it was harmful, because the space for it
was carved out of the normal per-thread svc32 stack, in effect cutting
that 8K stack in half. If svc32 mode used more than 4k of stack space it
wandered down into the undef mode stack, and then an undef exception would
overwrite a couple words on the stack while switching to svc32 mode,
corrupting the scv32 stack. Having another stack abut the bottom of the
svc32 stack also effectively mooted the guard page below the stack.

This work is based on analysis and patches submitted by Juergen Weiss.

Make sure the PCB is aligned on 8 bytes, we may use ldrd/strd to access it,
which may have strong alignment requirements.

Remove #include <machine/frame.h> from all the arm code that doesn't
really need it. That would be almost everywhere it was included. Add
it in a couple files that really do need it and were previously getting
it by accident via another header.

Remove fpe_sp_state as we don't support fpe.

Merging projects/armv6, part 1

Cummulative patch of changes that are not vendor-specific:
- ARMv6 and ARMv7 architecture support
- ARM SMP support
- VFP/Neon support
- ARM Generic Interrupt Controller driver
- Simplification of startup code for all platforms

Add a convenience macro for the returns_twice attribute, and apply it to
the prototypes of the appropriate functions (getcontext, savectx,
setjmp, sigsetjmp and vfork).

MFC after: 2 weeks

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

- Import the HEAD csup code which is the basis for the cvsmode work.

Start all license statements with /*-

Remove the pcb32_cstate field of struct pcb.

Do not declare curpcb.

Prototype makectx().

Import FreeBSD/arm kernel bits.
It only supports sa1110 (on simics) right now, but xscale support should come
soon.
Some of the initial work has been provided by :
Stephane Potvin <sepotvin at videotron.ca>
Most of this comes from NetBSD.