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

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

MFC r235063 (by netchild@):
- >500 static DTrace probes for the linuxulator
- DTrace scripts to check for errors, performance, ...
they serve mostly as examples of what you can do with the static probes
with moderate load the scripts may be overwhelmed, excessive lock-tracing
may influence program behavior (see the last design decission)

Design decissions:
- use "linuxulator" as the provider for the native bitsize; add the
bitsize for the non-native emulation (e.g. "linuxuator32" on amd64)
- Add probes only for locks which are acquired in one function and released
in another function. Locks which are aquired and released in the same
function should be easy to pair in the code, inter-function
locking is more easy to verify in DTrace.
- Probes for locks should be fired after locking and before releasing to
prevent races (to provide data/function stability in DTrace, see the
man-page of "dtrace -v ..." and the corresponding DTrace docs).

Manual merge futex part of r227293 (by ed@):
Mark MALLOC_DEFINEs static that have no corresponding MALLOC_DECLAREs.

MFC r235078 (by uqs@):
Fix make depend.

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

Approved by: re (implicit)

Extend struct sysvec with new method sv_schedtail, which is used for an
explicit process at fork trampoline path instead of eventhadler(schedtail)
invocation for each child process.

Remove eventhandler(schedtail) code and change linux ABI to use newly added
sysvec method.

While here replace explicit comparing of module sysentvec structure with the
newly created process sysentvec to detect the linux ABI.

Discussed with: kib

MFC after: 2 Week

Rename used_requeue and use it as bitwise field to store more flags.
Reimplement used_requeue logic with LINUX_XDEPR_REQUEUEOP flag.

By using the 32-bit Linux version of Sun's Java Development Kit 1.6
on FreeBSD (amd64), invocations of "javac" (or "java") eventually
end with the output of "Killed" and exit code 137.

This is caused by:
1. After calling exec() in multithreaded linux program threads are not
destroyed and continue running. They get killed after program being
executed finishes.

2. linux_exit_group doesn't return correct exit code when called not
from group leader. Which happens regularly using sun jvm.

The submitters fix this in a similar way to how NetBSD handles this.

I took the PRs away from dchagin, who seems to be out of touch of
this since a while (no response from him).

The patches committed here are from [2], with some little modifications
from me to the style.

PR: 141439 [1], 144194 [2]
Submitted by: Stefan Schmidt <stefan.schmidt@stadtbuch.de>, gk
Reviewed by: rdivacky (in april 2010)
MFC after: 5 days

Remove support for FUTEX_REQUEUE operation.
Glibc does not use this operation since 2.3.3 version (Jun 2004),
as it is racy and replaced by FUTEX_CMP_REQUEUE operation.
Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when
FUTEX_REQUEUE returned EINVAL.

Any application directly using FUTEX_REQUEUE without return
value checking are definitely broken.

Limit quantity of messages per process about unsupported
operation.

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

Include linux_futex.h before linux_emul.h

Approved by: kib (mentor)
MFC after: 6 days

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

MFP4: Turn emul_lock into a mutex.

Submitted by: rdivacky

MFp4 (112498):
Rename the locking flags to EMUL_DOLOCK and EMUL_DONTLOCK to prevent confusion.

Submitted by: rdivacky

MFp4:
- semi-automatic style fixes

MFP4:
Implement prctl().

Submitted by: rdivacky
Tested with: LTP

Move some stuff into headers where they belong.

Sponsored by: Google SoC 2006
Submitted by: rdivacky
Noticed by: jhb, ssouhlal

Style fixes to comments.

Sponsored by: Google SoC 2006
Submitted by: rdivacky
Noticed by: jhb, ssouhlal

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}.*)