Commit Graph

6 Commits

Author SHA1 Message Date
Attilio Rao
d8b878873e - Extract the IODEV_PIO interface from ia64 and make it MI.
In the end, it does help fixing /dev/io usage from multithreaded
  processes.
- On i386 and amd64 the old behaviour is kept but multithreaded
  processes must use the new interface in order to work well.
- Support for the other architectures is greatly improved, where
  necessary, by the necessity to define very small things now.

Manpage update will happen shortly.

Sponsored by:	Sandvine Incorporated
PR:		threads/116181
Reviewed by:	emaste, marcel
MFC after:	3 weeks
2010-04-28 15:38:01 +00:00
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
Ed Schouten
cacdd70cc7 Remove D_NEEDGIANT from io(4).
There is no need to mark this device node to use Giant. The only
architectures that use io(4) (i386 and amd64) only change a flag in
td->td_frame, which is only accessed by curthread.

Apart from this change, I think some fishy things may happen when using
/dev/io in multithreaded applications. I haven't tested, but looking at
the code, the flag doesn't get cleared when close() is called from
another thread, but this may not be this important.

I'm not removing D_NEEDGIANT from mem(4), because this driver isn't
Giant safe at all (it calls GIANT_REQUIRED).
2008-08-08 13:43:56 +00:00
Ed Schouten
721351876c Remove the unused major/minor numbers from iodev and memdev.
Now that st_rdev is being automatically generated by the kernel, there
is no need to define static major/minor numbers for the iodev and
memdev. We still need the minor numbers for the memdev, however, to
distinguish between /dev/mem and /dev/kmem.

Approved by:	philip (mentor)
2008-06-25 07:45:31 +00:00
Mark Murray
ce46e2059e Add module versions. 2004-08-02 20:42:28 +00:00
Mark Murray
8ab2f5ecc5 Break out the MI part of the /dev/[k]mem and /dev/io drivers into
their own directory and module, leaving the MD parts in the MD
area (the MD parts _are_ part of the modules). /dev/mem and /dev/io
are now loadable modules, thus taking us one step further towards
a kernel created entirely out of modules. Of course, there is nothing
preventing the kernel from having these statically compiled.
2004-08-01 11:40:54 +00:00