Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

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

Move arm's devmap to some generic place, so it can be used
by other architectures.

Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D6091
Sponsored by: DARPA, AFRL
Sponsored by: HEIF5

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.

Move bs_unimplemented() to bus_space_generic.c so it can be shared.

Revise the arm bus_space implementation to avoid dereferencing the tag on
every operation to retrieve the bs_cookie value almost nothing actually uses.

The bus_space struct contains a private data pointer (poorly named bs_cookie,
now renamed to bs_privdata) which is used only by a few old armv4 xscale
implementations. The bus_space functions were all defined to take this
value as the first parameter instead of the bus_space_tag_t, requiring all
the inline macro and function expansions to dereference the tag to pass it
to another function, which never uses it. Now all the functions take the tag
as the first parameter and retrieve the privdata if they need it.

Also fix a couple bus_space_unmap() implementations that were calling
kva_free() instead of pmap_unmapdev().

Discussed with: cognet

Add cpu_l2cache_drain_writebuf(), use it to implement generic_bs_barrier().

On modern ARM SoCs the L2 cache controller sits between the CPU and the
AXI bus, and most on-chip memory-mapped devices are on the AXI bus. We
map the device registers using the 'Device' memory attribute, which means
the memory is not cached, but writes to it are buffered. Ensuring that a
write has made it all the way to a device may require that the L2
controller take some action.

There is currently only one implementation of the new function, for the
PL310 cache controller. It invokes a function that the controller
manual calls "cache sync" but it actually has nothing to do with cache at
all, it triggers a drain of all pending store buffer writes and it blocks
until they complete.

The sheeva and xscale L2 controllers (which predate the concept of Device
memory) don't seem to have a corresponding function. It appears that the
standard armv5 drain_writebuf function includes draining all the way
through the L2 controller.

Don't try to find a static mapping before calling pmap_mapdev(), that logic
is now part of pmap_mapdev() and doesn't need to be duplicated here.
Likewise for unmapping.

Begin reducing code duplication in arm pmap.c and pmap-v6.c by factoring
out common code related to mapping device memory into a new devmap.c file.

Remove the growing duplication of code that used pmap_devmap_find_pa() and
then did some math with the returned results to generate a virtual address,
and likewise in reverse to get a physical address. Now there are a pair
of functions, arm_devmap_vtop() and arm_devmap_ptov(), to do that. The
bus_space_map() implementations are rewritten in terms of these.

- The address lies in the bus space handle, not in the cookie
- Use the right address when calling kva_free()

Replace kernel virtual address space allocation with vmem. This provides
transparent layering and better fragmentation.

- Normalize functions that allocate memory to use kmem_*
- Those that allocate address space are named kva_*
- Those that operate on maps are named kmap_*
- Implement recursive allocation handling for kmem_arena in vmem.

Reviewed by: alc
Tested by: pho
Sponsored by: EMC / Isilon Storage Division

In generic_bs_map(), use kmem_alloc_nofault() instead of kmem_alloc(), as we
only need virtual addresses.

Submitted by: alc

Now really add the bus_space_generic.c file...

Reviewed by: sam
Approved by: cognet (mentor)