MFC r309531,r309553,r309604:

r309531:
Implement fake pmap_mapdev_attr() for ARMv6. This function is referenced,
but never called from DRM2 code. Also, real behavior of pmap_mapdev_attr()
in ARM world is unclear as we don't have any additional attribute for a
device memory type.
r309553:
Fix build breakage caused by r309531.
r309604:
Fix the armv6 build after r309553.

MFC r319896,r320054:

r319896:
Implement tunable CPU quirks. These quirks are intended for optimizing CPU
performance, not for applying errata workarounds. Nobody can expect that
CPU with unfixed errata is stable enough to execute the kernel until quirks
are applied.
r320054:
Manually load tunable CPU quirks. These are needed too early, far before
SYSINIT is processed.

MFC r318021,r318251:

r318021:
Introduce pmap_remap_vm_attr(), it allows to remap one VM memattr class to
another.
r318251:
Clarify usage rules for pmap_remap_vm_attr(). Not a functional change.

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

Remove not used definitions and fix some style nits.
No functional changes.

Move common definitions from both pmap-v4.h and pmap-v6.h into pmap.h.
(1) MI interface needed for vm subsystem.
(2) MD interface created for ARM architecture to be used in files
shared by armv4 and armv6 platforms.

Rename pmap.h to pmap-v4.h and remove pmap-v6.h include from it.
Create new pmap.h which includes specific header according to
__ARM_ARCH.

Note that <machine/pmap.h> is included from <vm/pmap.h> so one common
<machine/pmap.h> must exist.

Do not use PMAP_DOMAIN_KERNEL definition for __ARM_ARCH >= 6 as domains
are not utilized there. Only domain #0 is used and there is no reference
to it in the whole pmap-v6.c. Thus initialize domain access register in
locore-v6.c without reference too.

Remove unneeded vector_page_setprot() for __ARM_ARCH >= 6. A vector
page is always mapped in KVA space and so it's always writeable.

Include pte-v6.h only where needed.

Remove pd_prot and pd_cache members from struct arm_devmap_entry.
The struct is used for definition of static device mappings which
should always have same protection and attributes.

Make VM_MEMATTR_xxx definitions independent on pmap internals
for __ARM_ARCH >= 6.

It's TEX class number now, so it still has some meaning.

Partly revert r295168 and define PTE_DEVICE in pmap-v6.h header again.
It turned out that devmap.c is not only file in which PTE_DEVICE
is used and simultaneously, built for both armv4 and armv6 platforms.

When I tried to build all arm kernels before r295168 commit, it was
hid by some other local changes in my tree. I hope that this is just
temporary workaround before VM_MEMATTR_DEVICE could be used instead of
PTE_DEVICE outside of pmap code for __ARM_ARCH < 6.

Use pmap_preboot_map_attr() directly in arm_devmap_bootstrap()
instead of hiding behind pmap_map_chunk(). It's not longer needed
after old pmap-v6 code was removed.

For compatibility with __ARM_ARCH < 6, define PTE_DEVICE in devmap.c
file. Certainly, it would be nice if VM_MEMATTR_DEVICE could be used
even for __ARM_ARCH < 6.

Make pmap_preboot_map_attr() vm subsystem compliant, so its arguments
do not depend on pmap internals. This is a preparation for hiding
internal pmap definitions as much as possible from the rest of system.

Simultaneously, the protection argument evaluation is fixed. Happily,
it did not effect the mappings. And it's the reason why it was not fixed
earlier.

Remove all remaining references to old and not more used struct
pmap_devmap, pmap_devmap_bootstrap() and pmap_devmap[]. It was
replaced in r257660.

Retire pmap_pte_init_mmu_v6() which was used by old pmap-v6.

Use kernel_pmap directly instead of pmap_kernel(). The kernel_pmap is
already used for __ARM_ARCH >= 6 and so even for __ARM_ARCH < 6 on some
common places.

Create new pmap dump interface for minidump and use it for existing
pmap implementations on ARM. This way minidump code can be used without
any platform specific modification.

Also, this is the last piece missing for ARM_NEW_PMAP.

Differential Revision: https://reviews.freebsd.org/D5023

Local TLB flush is sufficient in pmap_remove_pages().

(1) The pmap argument passed to the function must be current pmap only.
(2) The process must be single threaded as the function is called either
when a process is exiting or from exec_new_vmspace().

Remove pmap_tlb_flush_ng() which is not used anywhere now.

Approved by: kib (mentor)

Make usermode variable the bool type. It's already used that way.

Suggested by: kib
Approved by: kib (mentor)

Retire pmap_dmap_iscurrent(). It is only a wrapper around pmap_is_current(), and is no longer called.

Retire pmap_lazyfix(). This function only existed in the new armv6 pmap
because the i386 pmap on which the new armv6 pmap is based had it, and in
r281707 pmap_lazyfix() was removed from the i386 pmap.

Discussed with: kib
Submitted by: Michal Meloun (via Svatopluk Kraus)

Add a pmap_kremove_device() to undo mappings made with pmap_kenter_device().

Previously we used pmap_kremove(), but with ARM_NEW_PMAP it does the remove
in a way that isn't SMP-coherent (which is appropriate in some circumstances
such as mapping/unmapping sf buffers). With matching enter/remove routines
for device mappings, each low-level implementation can do the right thing.

Reviewed by: Svatopluk Kraus <onwahe@gmail.com>

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>