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

In pci_cfgregread() and pci_cfgregwrite(), multiplex the domain and
bus number into the bus argument. The bus number occupies the least
significant 8 bits. The PCI domain occupies the most significant 24
bits.

On the Altix 350, the PCI domain is a required parameter, but
changing the prototype of the pci_cfgreg*() functions to include a
separate domain argument has wide-spread consequences across the
supported architectures. We'd be changing a known interface.

Multiplexing is an acceptable kluge to give us what we need with
manageable impact. Note that the PCI bus number fits in 8 bits,
so the multiplexing of the domain is a backward compatible change.

Disable interrupts when calling into SAL for PCI configuration
cycles. This serves 2 purposes:
1. It prevents preemption and CPU migration while running SAL code.
2. It reduces the chance of stack overflows: we're supposed to enter
SAL with at least 16KB of either memory- or register stack space,
which we can't do without switching to a different stack.

In pci_cfgregread() and pci_cfgregwrite(), validate the arguments and check
that the alignment matches the width of the read or write.

Delete legacy pcib code - we can't possibly work without acpi on ia64.

The encoding for the bus being passed to SAL was completely wrong.

Start hooking up devices.