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

Use MK_SSP=no after including bsd.own.mk to disable SSP instead of user-knob
WITH[OUT]_SSP to avoid hitting an error if user has WITH_SSP in their
make.conf. Ports now use this knob.

make[7]: "/usr/src/share/mk/bsd.own.mk" line 466: WITH_SSP and
WITHOUT_SSP can't both be set.

This is similar to previous cleanup done in r188895

Approved by: bapt
Reviewed by: jlh (earlier version)
Approved by: re (marius)
MFC after: 1 week

Make sure to synchronize icache for the newly loaded loader. Not an issue
on most systems, when the relevant icache lines are not full.

MFC after: 2 weeks

Experimental support for booting CHRP-type PowerPC systems from hard disks.

Provide support in loader for booting 64-bit PowerPC kernels. Like amd64,
64-bit PowerPC kernels are loaded by a 32-bit loader, since nearly all
powerpc64 firmwares execute in 32-bit mode.

Add a simple HFS boot block implementation for booting PowerPC macs. It creates
a small HFS filesystem with a CHRP boot script and an early-stage bootloader
derived from the sparc64 boot block.

Obtained from: sparc64