Merge the fueword(9) and casueword(9). In particular,

MFC r273783:
Add fueword(9) and casueword(9) functions.
MFC note: ia64 is handled like arm, with NO_FUEWORD define.

MFC r273784:
Replace some calls to fuword() by fueword() with proper error checking.

MFC r273785:
Convert kern_umtx.c to use fueword() and casueword().
MFC note: the sys__umtx_lock and sys__umtx_unlock syscalls are not
converted, they are removed from HEAD, and not used. The do_sem2*()
family is not yet merged to stable/10, corresponding chunk will be
merged after do_sem2* are committed.

MFC r273788 (by jkim):
Actually install casuword(9) to fix build.

MFC r273911:
Add type qualifier volatile to the base (userspace) address argument
of fuword(9) and suword(9).

MFC r258800, r258802, r258805, r258806, r258807, r258851, r258857,
r259199, r259484, r259513, r259514, r259516

The kernel stack guard pages are only below the stack pointer, not above.

Remove unnecessary double-setting of the thread's onfault state in
copyinstr().

Open Firmware mandates that certain cross-references, in particular those
in /chosen, be ihandles. The ePAPR spec makes those cross-reference phandles,
since FDT has no concept of ihandles. Have the OF FDT CI module interpret
queries about ihandles as cross-reference phandles.

Real OF systems have an ihandle under /chosen/stdout, not a phandle. Use
the right type.

Rearchitect platform memory map parsing to make it less
Open Firmware-centric.

Remove fdtbus_bs_tag definition, which is now obsolete. The remainder of
this file is also slated for future demolition.

Return the correct IEEE 1275 code for "nextprop".

Use the common Open Firmware PCI interrupt routing code instead of the
duplicate version in dev/fdt.

Configure interrupt sense based on device tree information.

Simplify the ofw_bus_lookup_imap() API slightly: make it allocate maskbuf
internally instead of requiring the caller to allocate it.

MFC r258002, r258024, r258027, r258051, r258052, r258243, r258244, r258002,
r258024, r258027, r258051, r258052, r258243,

Follow up r223485, which made AIM use the ABI thread pointer instead of
PCPU fields for curthread, by doing the same to Book-E.

Use the same implementation of copyinout.c for both AIM and Book-E.

Actually add IOMMU domain to the list of known mappings.

Following the approach with ACPI DMAR on x86, split IOMMU handling into
a variant PCI bus instead of trying to shoehorn it into the PCI host bridge
adapter.

Make sure that TLB1 mappings are aligned correctly.

Merge the fueword(9) and casueword(9). In particular,

MFC r273783:
Add fueword(9) and casueword(9) functions.
MFC note: ia64 is handled like arm, with NO_FUEWORD define.

MFC r273784:
Replace some calls to fuword() by fueword() with proper error checking.

MFC r273785:
Convert kern_umtx.c to use fueword() and casueword().
MFC note: the sys__umtx_lock and sys__umtx_unlock syscalls are not
converted, they are removed from HEAD, and not used. The do_sem2*()
family is not yet merged to stable/10, corresponding chunk will be
merged after do_sem2* are committed.

MFC r273788 (by jkim):
Actually install casuword(9) to fix build.

MFC r273911:
Add type qualifier volatile to the base (userspace) address argument
of fuword(9) and suword(9).

MFC r258800, r258802, r258805, r258806, r258807, r258851, r258857,
r259199, r259484, r259513, r259514, r259516

The kernel stack guard pages are only below the stack pointer, not above.

Remove unnecessary double-setting of the thread's onfault state in
copyinstr().

Open Firmware mandates that certain cross-references, in particular those
in /chosen, be ihandles. The ePAPR spec makes those cross-reference phandles,
since FDT has no concept of ihandles. Have the OF FDT CI module interpret
queries about ihandles as cross-reference phandles.

Real OF systems have an ihandle under /chosen/stdout, not a phandle. Use
the right type.

Rearchitect platform memory map parsing to make it less
Open Firmware-centric.

Remove fdtbus_bs_tag definition, which is now obsolete. The remainder of
this file is also slated for future demolition.

Return the correct IEEE 1275 code for "nextprop".

Use the common Open Firmware PCI interrupt routing code instead of the
duplicate version in dev/fdt.

Configure interrupt sense based on device tree information.

Simplify the ofw_bus_lookup_imap() API slightly: make it allocate maskbuf
internally instead of requiring the caller to allocate it.

MFC r258002, r258024, r258027, r258051, r258052, r258243, r258244, r258002,
r258024, r258027, r258051, r258052, r258243,

Follow up r223485, which made AIM use the ABI thread pointer instead of
PCPU fields for curthread, by doing the same to Book-E.

Use the same implementation of copyinout.c for both AIM and Book-E.

Actually add IOMMU domain to the list of known mappings.

Following the approach with ACPI DMAR on x86, split IOMMU handling into
a variant PCI bus instead of trying to shoehorn it into the PCI host bridge
adapter.

Make sure that TLB1 mappings are aligned correctly.