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

The new binutils has correctly redefined MAXPAGESIZE on amd64 as 0x200000
instead of 0x100000. As a side effect, an amd64 kernel now loads at
physical address 0x200000 instead of 0x100000. This is probably for the
best because it avoids the use of a 2MB page mapping for the first 1MB of
the kernel that also spans the fixed MTRRs. However, getmemsize() still
thinks that the kernel loads at 0x100000, and so the physical memory between
0x100000 and 0x200000 is lost. Fix this problem by replacing the hard-wired
constant in getmemsize() by a symbol "kernphys" that is defined by the
linker script.

In collaboration with: kib

Merge binutils 2.17.50 to head. This brings a number of improvements to
x86 CPU support, better support for powerpc64, some new directives, and
many other things. Bump __FreeBSD_version, and add a note to UPDATING.

Thanks to the many people that have helped to test this.

Obtained from: projects/binutils-2.17

Provide the _start_ctors and _stop_ctors symbols. As on i386, the addresses
of these are the start and end of the .ctors section.

Sync up with the files in the hammer branch in the p4 tree to get basic
AMD64 support. There is still more to add.

Add two symbols start_ctors and stop_ctors to allow us to find the
.ctors section so we can call the constructors.

Use the new freebsd output format from Binutils 2.13.1.

Remove hard coded magic load address. Now to change the load address,
we just have to change the pmap.h constants and ld will automatically
adapt based on the "kernbase" symbol.

Add $FreeBSD$
Make the alpha linker script more like the i386 version - delete the
/usr/local and egcs directories

Remove a rather bogus search path reference..

Increased kernel virtual address space to 1GB. NOTE: You MUST have fixed
bootblocks in order to boot the kernel after this! Also note that this
change breaks BSDI BSD/OS compatibility.
Also increased default NKPT to 17 so that FreeBSD can boot on machines
with >=2GB of RAM. Booting on machines with exactly 4GB requires other
patches, not included.

Make the ELF kernel build produce a dynamic executable (!). This enables
the in-kernel linker to access the _DYNAMIC data for doing loadable elf
modules. The alpha kernel is already done this way, I've borrowed some of
the hacks from there.

This is primarily aimed at the 3-stage boot process which is intended to
be able to do pre-loading of kernel modules.

Note that the entry point isn't 0xf0100000 any more, it'll be a little
further on - but this value is stored in the headers. I don't think this
will be a problem, but I'm sure somebody will tell me if it is. :-)

I'm not sure if btxboot is going to like this, it doesn't do proper ELF
header checking and assumes that there are exactly two program header
entries and that they are both PT_LOAD entries - a bad assumption.