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

Better support memory mapped console devices, such as VGA and EFI
frame buffers and memory mapped UARTs.

1. Delay calling cninit() until after pmap_bootstrap(). This makes
sure we have PMAP initialized enough to add translations. Keep
kdb_init() after cninit() so that we have console when we need
to break into the debugger on boot.
2. Unfortunately, the ATPIC code had be moved as well so as to
avoid a spurious trap #30. The reason for which is not known
at this time.
3. In pmap_mapdev_attr(), when we need to map a device prior to the
VM system being initialized, use virtual_avail as the KVA to map
the device at. In particular, avoid using the direct map on amd64
because we can't demote by virtue of not being able to allocate
yet. Keep track of the translation.
Re-use the translation after the VM has been initialized to not
waste KVA and to satisfy the assumption in uart(4) that the handle
returned for the low-level console is the same as later returned
when the device is probed and attached.
4. In pmap_unmapdev() remove the mapping from the table when called
pre-init. Otherwise keep the mapping. During bus probe and attach
device resources are mapped and unmapped multiple times, which
would have us destroy the mapping used by the low-level console.
5. In pmap_init(), set pmap_initialized to signal that we're not
pre-init anymore. On amd64, bring the direct map in sync with the
translations created at that time.
6. Implement bus_space_map() and bus_space_unmap() for real: when
the tag corresponds to memory space, call the corresponding
pmap_mapdev() and pmap_unmapdev() functions to construct and
actual handle.
7. In efifb.c and vt_vga.c, remove the crutches and hacks and simply
call pmap_mapdev_attr() or bus_space_map() as desired.

Notes:
1. uart(4) already used bus_space_map() during low-level console
setup but since serial ports have traditionally been I/O port
based, the lack of a proper implementation for said function
was not a problem. It has always supported memory mapped UARTs
for low-level consoles by setting hw.uart.console accordingly.
2. The use of the direct map on amd64 without setting caching
attributes has been a bigger problem than previously thought.
This change has the fortunate (and unexpected) side-effect of
fixing various EFI frame buffer problems (though not all).

PR: 191564, 194952

Special thanks to:
1. XipLink, Inc -- generously donated an Intel Bay Trail E3800
based eval board (ADLE3800PC).
2. The FreeBSD Foundation, in particular emaste@ -- for UEFI
support in general and testing.
3. Everyone who tested the proposed for PR 191564.
4. jhb@ and kib@ for being a soundboard and applying a clue bat
if so needed.

Update NetBSD Foundation copyrights to 2-clause BSD

The NetBSD Foundation states "Third parties are encouraged to change the
license on any files which have a 4-clause license contributed to the
NetBSD Foundation to a 2-clause license."

This change removes clauses 3 and 4 from copyright / license blocks that
list The NetBSD Foundation as the only copyright holder.

Sponsored by: The FreeBSD Foundation

Add bus_space_read_8 and bus_space_write_8 for amd64.

Rather than trying to KASSERT for callers that invoke this on
IO tags, either do nothing (for write_8) or return ~0 (for read_8).
Using KASSERT here just makes bus.h too messy from both
polluting bus.h with systm.h (for any number of drivers that include
bus.h without first including systm.h) or ports that use bus.h
directly (i.e. libpciaccess) as reported by zeising@.

Also don't try to implement all of the other bus_space functions for
8 byte access since realistically only these two are needed for some
devices that expose 64-bit memory-mapped registers.

Put the amd64-specific functions here rather than sys/amd64/include/bus.h
so that we can keep this header unified for x86, as requested by mdf@
and tijl@.

Submitted by: Carl Delsey <carl.r.delsey@intel.com>
MFC after: 3 days

Revert r243960 based on feedback regarding keeping x86 headers unified
(mdf@, tijl@) and use of KASSERT/systm.h in bus.h (zeising@, bde@).

Alternate implementation will be made in a separate commit.

Add amd64 implementations for 8-byte bus_space routines.

Submitted by: Carl Delsey <carl.r.delsey@intel.com>
Discussed with: jhb, rwatson
Reviewed by: jimharris
MFC after: 1 week

Add an unified macro to deny ability from the compiler to reorder
instruction loads/stores at its will.
The macro __compiler_membar() is currently supported for both gcc and
clang, but kernel compilation will fail otherwise.

Reviewed by: bde, kib
Discussed with: dim, theraven
MFC after: 2 weeks

Merge amd64 and i386 bus.h and move the resulting header to x86. Replace
the original amd64 and i386 headers with stubs.

Rename (AMD64|I386)_BUS_SPACE_* to X86_BUS_SPACE_* everywhere.

Reviewed by: imp (previous version), jhb
Approved by: kib (mentor)

Revert r216134. This checkin broke platforms where bus_space are macros:
they need to be a single statement, and do { } while (0) doesn't work in this
situation so revert until a solution can be devised.

Disallow passing in a count of zero bytes to the bus_space(9) functions.

Passing a count of zero on i386 and amd64 for [I386|AMD64]_BUS_SPACE_MEM
causes a crash/hang since the 'loop' instruction decrements the counter
before checking if it's zero.

PR: kern/80980
Discussed with: jhb

Merge/sync with i386: various cosmetic tweaks

Remove bus_{mem,p}io.h and related code for a micro-optimization on i386
and amd64. The optimization is a trivial on recent machines.

Reviewed by: -arch (imp, marcel, dfr)

MFi386: remove comment

Break out the definition of bus_space_{tag,handle}_t and a few other types
into _bus.h to help with name space polution from including all of bus.h.
In a few days, I'll commit changes to the MI code to take advantage of thse
sepration (after I've made sure that these changes don't break anything in
the main tree, I've tested in my trees, but you never know...).

Suggested by: bde (in 2002 or 2003 I think)
Reviewed in principle by: jhb

MFi386: track bus.h changes (unsplit bus_${machine}.h)

AMD64 physical space is much larger than i386, de-i386 the bus_space and
bus_dma MD code for AMD64. (And a trivial ifdef update in dev/kbd because
of this). More updates are needed here to take advantage of the 64 bit
instructions.

Approved by: re (blanket amd64/*)

Commit MD parts of a loosely functional AMD64 port. This is based on
a heavily stripped down FreeBSD/i386 (brutally stripped down actually) to
attempt to get a stable base to start from. There is a lot missing still.
Worth noting:
- The kernel runs at 1GB in order to cheat with the pmap code. pmap uses
a variation of the PAE code in order to avoid having to worry about 4
levels of page tables yet.
- It boots in 64 bit "long mode" with a tiny trampoline embedded in the
i386 loader. This simplifies locore.s greatly.
- There are still quite a few fragments of i386-specific code that have
not been translated yet, and some that I cheated and wrote dumb C
versions of (bcopy etc).
- It has both int 0x80 for syscalls (but using registers for argument
passing, as is native on the amd64 ABI), and the 'syscall' instruction
for syscalls. int 0x80 preserves all registers, 'syscall' does not.
- I have tried to minimize looking at the NetBSD code, except in a couple
of places (eg: to find which register they use to replace the trashed
%rcx register in the syscall instruction). As a result, there is not a
lot of similarity. I did look at NetBSD a few times while debugging to
get some ideas about what I might have done wrong in my first attempt.

Add the following functions/macros to support byte order conversions and
device drivers for bus system with other endinesses than the CPU (using
interfaces compatible to NetBSD):

- bwap16() and bswap32(). These have optimized implementations on some
architectures; for those that don't, there exist generic implementations.
- macros to convert from a certain byte order to host byte order and vice
versa, using a naming scheme like le16toh(), htole16().
These are implemented using the bswap functions.
- stream bus space access functions, which do not perform a byte order
conversion (while the normal access functions would if the bus endianess
differs from the CPU endianess).

htons(), htonl(), ntohs() and ntohl() are implemented using the new
functions above for kernel usage. None of the above interfaces is currently
exported to user land.

Make use of the new functions in a few places where local implementations
of the same functionality existed.

Reviewed by: mike, bde
Tested on alpha by: mike

- Moved the bus_dma declarations from bus_{at386,pc98}.h into bus_dma.h.
(bus_dma.h is repo-copied from bus_at386.h)
- Added '#include <machine/bus_dma.h>' into bus.h for backward compatibility.

Added indirect pio into the bus space stuff for the NEC PC-98. bus.h
includes one of bus_at386.h and bus_pc98.h. Becuase only bus_pc98.h
supports indirect pio and bus_at386.h is identical to old bus.h, there
is no functional change in PC-AT's kernels. That is, it cannot cause
performance loss.

Submitted by: nyan
Reviewed by: imp
bde and luoqi provided useful comments for earlier version.

Fix clobbers so that GENERIC may compile with GCC 2.95.2.

Historically, the documentation of extended asm was lacking, namely you
should NOT specify the same register as an input, and a clobber.
If the register is clobbered, it should be specified as an output as well,
e.g., by linking input and output through the "number" notation.
(Beware of lvalues, some local variables needed...)

URL:http://egcs.cygnus.com/faq.html

In versions up to egcs-1.1.1, the compiler did not even warn about it,
but it was liable to output bad code. Newer egcs are pickier and simply
refuse to swallow such code.

Note, since *addr changes, it needs to be an output operand.
We might be excessive in saying that all memory has changed.

Obtained from: OpenBSD
w/extra thanks to Marc Espie <Marc.Espie@liafa.jussieu.fr>

$Id$ -> $FreeBSD$

Improve compatibility with other systems by changing the default
behavior slightly.

If machine/bus.h is included, but neither bus_memio.h nor bus_pio.h
are included, then behave as if both were included.

This won't change existing drivers, all of which include one or more
of bus_{p,mem}io.h, but will allow drivers from other systems to come
over with fewer changes. I freely admit that this might not be
optimal for some drivers, but those drivers can be optimized for
FreeBSD after the initial bringup happens.

Without the change, there is a bug that preclude drivers from
compiling with strange warning/errors.

I've been running this here for a while now w/o ill effects.

Reviewed by: gibbs
Not objected to by: bde, arch@ list.

Don't pretend to support ix86's with 16-bit ints by using longs just
to ensure 32-bit variables. Doing so broke ix86's with 64-bit longs.

Implement bus_dmamem_* functions and correct a few nits reported by Peter Wemm.

Support compiling with `gcc-pedantic' (don't use hard newlines in
(asm) string constants or trailing commas in enum declarations).

Implementation of Bus Space for FreeBSD-x86.

Obtained From: NetBSD