* Add new heap manager.
* Convert OHCI driver to use new heap manager.
* Convert UHCI driver to use new heap manager.
* Convert EHCI driver to use new heap manager.
* Convert XHCI driver to use new heap manager.
* Convert SMP to use new heap manager.
* Add a "usbinit" boot option to handle various buggy USB devices.
This replaces the "keyboard=buggy-usb" option, and adds a second
workaround to handle the problem seen in issue #107.
We need to pass the physical address of the MADT to parse_madt(), not the
virtual address of the table signature, because parse_madt() needs to call
map_region() again to ensure the full table is mapped into virtual memory.
The old barrier implementation was very slow when running on a multi-socket
machine (pcmemtest issue 16).
The new implementation provides two options:
- when blocked, spin on a thread-local flag
- when blocked, execute a HLT instruction and wait for a NMI
The first option might be faster, but we need to measure it to find out. A
new boot command line option is provided to select between the two, with a
third setting that uses a mixture of the two.
We only map the first 4GB of physical address space, so if the ACPI tables
or local APIC are located above 4GB, or are overlaid when we remap something
else (e.g. the video frame buffer), we need to map them to somewhere we can
access. The ACPI tables are only used during startup, but the local APIC
will be needed when we are running tests if we are saving power by halting
idle CPU cores and using a NMI to wake them up.
