freebsd-nq/sys/dev/io
Marcel Moolenaar 409a390c33 Use io(4) for I/O port access on ia64, rather than through sysarch(2).
I/O port access is implemented on Itanium by reading and writing to a
special region in memory. To hide details and avoid misaligned memory
accesses, a process did I/O port reads and writes by making a MD system
call. There's one fatal problem with this approach: unprivileged access
was not being prevented. /dev/io serves that purpose on amd64/i386, so
employ it on ia64 as well. Use an ioctl for doing the actual I/O and
remove the sysarch(2) interface.

Backward compatibility is not being considered. The sysarch(2) approach
was added to support X11, but support for FreeBSD/ia64 was never fully
implemented in X11. Thus, nothing gets broken that didn't need more work
to begin with.

MFC after:	1 week
2010-01-11 18:10:13 +00:00
..
iodev.c Use io(4) for I/O port access on ia64, rather than through sysarch(2). 2010-01-11 18:10:13 +00:00