Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

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

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

Add reader/writer lock around mem_range_attr_get() and mem_range_attr_set().
Compile sys/dev/mem/memutil.c for all supported platforms and remove now
unnecessary dev_mem_md_init(). Consistently define mem_range_softc from
mem.c for all platforms. Add missing #include guards for machine/memdev.h
and sys/memrange.h. Clean up some nearby style(9) nits.

MFC after: 1 month

Initial suspend/resume support for amd64.

This code is heavily inspired by Takanori Watanabe's experimental SMP patch
for i386 and large portion was shamelessly cut and pasted from Peter Wemm's
AP boot code.

Fix module builds for i386 and amd64.

Some BIOSs are using MTRR values that are only documented under NDA
to control the mapping of things like the ACPI and APM into memory.

The problem is that starting X changes these values, so if something
was using the bits of BIOS mapped into memory (say ACPI or APM),
then next time they access this memory the machine would hang.

This patch refuse to change MTRR values it doesn't understand,
unless a new "force" option is given. This means X doesn't change
them by accident but someone can override that if they really want
to.

PR: 28418
Tested by: Christopher Masto <chris@netmonger.net>,
David Bushong <david@bushong.net>,
Santos <casd@myrealbox.com>
MFC after: 1 week

Make the MTRR code a bit more defensive - this should help people
trying to run X on some Athlon systems where the BIOS does odd things
(mines an ASUS A7A266, but it seems to also help on other systems).

Here's a description of the problem and my fix:

The problem with the old MTRR code is that it only expects
to find documented values in the bytes of MTRR registers.
To convert the MTRR byte into a FreeBSD "Memory Range Type"
(mrt) it uses the byte value and looks it up in an array.
If the value is not in range then the mrt value ends up
containing random junk.

This isn't an immediate problem. The mrt value is only used
later when rewriting the MTRR registers. When we finally
go to write a value back again, the function i686_mtrrtype()
searches for the junk value and returns -1 when it fails
to find it. This is converted to a byte (0xff) and written
back to the register, causing a GPF as 0xff is an illegal
value for a MTRR byte.

To work around this problem I've added a new mrt flag
MDF_UNKNOWN. We set this when we read a MTRR byte which
we do not understand. If we try to convert a MDF_UNKNOWN
back into a MTRR value, then the new function, i686_mrt2mtrr,
just returns the old value of the MTRR byte. This leaves
the memory range type unchanged.

I have seen one side effect of the fix, which is that ACPI calls
after X has been run seem to hang my machine. As running X would
previously panic the machine, this is still an improvement ;-)

I'd like to MFC this before the 4.6 code freeze - please let me
know if it causes any problems.

PR: 28418, 25958
Tested by: jkh, Christopher Masto <chris@netmonger.net>
MFC after: 2 weeks

Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is consistant with the other
BSD's who made this change quite some time ago. More commits to come.

Make the error return from mem_range_attr_get actually do something useful
(return an error to the caller)

Add a hook that can be called to initialise a slave processor's memory
range attributes after they have been extracted from the master.

Hook up the i686 MP code to do this for each AP.

Be more careful about printing the default memory type for the i686.

Suggestions from: luoqi

Generic memory range attribute interface.