Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Yet another unimplemented futex operation, print out about.

Submitted by: arundel
MFC after: 1 month.

Implement a futex BITSET op.

Submitted by: arundel
MFC after: 1 month.

- print out the PID and program name of the program trying to use an
unsupported futex operation
- for those futex operations which are known to be not supported,
print out which futex operation it is
- shortcut the error return of the unsupported FUTEX_CLOCK_REALTIME in
some cases:
FUTEX_CLOCK_REALTIME can be used to tell linux to use
CLOCK_REALTIME instead of CLOCK_MONOTONIC. FUTEX_CLOCK_REALTIME
however must only be set, if either FUTEX_WAIT_BITSET or
FUTEX_WAIT_REQUEUE_PI are set too. If that's not the case
we can die with ENOSYS right at the beginning.

Submitted by: arundel
Reviewed by: rdivacky (earlier iteration of the patch)
MFC after: 1 week

Move extern variable definitions to the header file.

Approved by: kib (mentor)
MFC after: 1 month

Ignore FUTEX_FD op, as it is done by linux.

Approved by: kib (mentor)
MFC after: 2 weeks

Make robust futexes work on linux32/amd64. Use PTRIN to read
user-mode pointers. Change types used in the structures definitions to
properly-sized architecture-specific types.

Submitted by: dchagin
MFC after: 1 week

Implement robust futexes. Most of the code is modelled after
what Linux does. This is because robust futexes are mostly
userspace thing which we cannot alter. Two syscalls maintain
pointer to userspace list and when process exits a routine
walks this list waking up processes sleeping on futexes
from that list.

Reviewed by: kib (mentor)
MFC after: 1 month

o Add stub support for some new futex operations,
so the annoying message is not printed.

o Don't warn about FUTEX_FD not being implemented
and return ENOSYS instead of 0 (eg. success).

o Clear FUTEX_PRIVATE_FLAG as we actually implement
only private futexes so there is no reason to
return ENOSYS when app asks for a private futex.
We don't reject shared futexes because they worked
just fine with our implementation so far.

Approved by: kib (mentor)
Tested by: bsam
MFC after: 1 week

MFp4 (110523, parts which apply cleanly):
semi-automatic style(9)

The futex stuff already differs a lot (only a small part does not differ)
from NetBSD, so we are already way off and can't apply changes from NetBSD
automatically. As we need to merge everything by hand already, we can even
make the files comply to our world order.

Add some new files needed for linux 2.6.x compatibility.

Please don't style(9) the NetBSD code, we want to stay in sync. Not imported
on a vendor branch since we need local changes.

Sponsored by: Google SoC 2006
Submitted by: rdivacky
With help from: manu@NetBSD.org
Obtained from: NetBSD (linux_{futex,time}.*)