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)

Add some checks to ensure that Capsicum is behaving correctly, and add some
more explicit comments about what's going on and what future maintainers
need to do when e.g. adding a new operation to a sys_machdep.c.

Approved by: mentor(rwatson), re(bz)

Add a small API to manage the MD user trap structures. Specifically, we
now use a pool mutex to manage the reference counts. This fixes races
resulting in use-after-free.

Tested by: kris, David Cornejo dave at dogwood dot com
Reported by: bmilekic's MemGuard
MFC after: 1 week

Prefer new location of pci include files (which have only been in the
tree for two or more years now), except in a few places where there's
code to be compatible with older versions of FreeBSD.

- Push down Giant into the sysarch() calls that still need Giant.
- Standardize on EINVAL rather than EOPNOTSUPP if the sysarch op value is
invalid.

Back out M_* changes, per decision of the TRB.

Approved by: trb

Remove M_TRYWAIT/M_WAITOK/M_WAIT. Callers should use 0.
Merge M_NOWAIT/M_DONTWAIT into a single flag M_NOWAIT.

Add support for an alternate signal trampoline; add a sysarch call to register
an alternate trampoling with the kernel.

Implement user trap delivery as specified by the sparc abi. This provides
an efficient way for the kernel to bounce certain mundane traps back to
userland for handling there. A user trap handler returns directly to the
trapping user code, rather than going through the kernel again. Only a
handful of instructions are actually executed in kernel mode.
Implement sysarch(SPARC_UTRAP_INSTALL).
Add code to handle sharing of the user trap table across forks and unsharing
at exec.

This can be used to implement efficient tracking of floating point register
usage in userland, fe by a thread library, and to handle alignment fault
fixups and instruction emulation in userland, for which the code may need
to be different for 32bit and 64bit binaries.

Newer versions of gcc have a bug where switch statements with only
a default: label cause a segmentation fault. So just return EINVAL
from sysarch.

Implement sysarch().

KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after: ha ha ha ha

style(9) the structure definitions.

The author isn't a [UC] Regents. Correct the copyright language.

Flesh out the sparc64 port considerably. This contains:
- mostly complete kernel pmap support, and tested but currently turned
off userland pmap support
- low level assembly language trap, context switching and support code
- fully implemented atomic.h and supporting cpufunc.h
- some support for kernel debugging with ddb
- various header tweaks and filling out of machine dependent structures

Add skeleton machine dependent headers and c files for a port of freebsd
to a new architecture. This is the base of the sparc64 port, but contains
limited machine dependent code, and can be used a base for ports. Included
are:
- standard machine dependent headers, tweaked for a 64 bit, big endian
architecture, including empty versions of all the machine dependent
structures
- a machine independent atomic.h, which can be used until a port has
support for interrupts and the operations really need to be atomic
- stub versions of all the machine dependent functions, which panic
when called and print out the name of the function that needs to
be implemented. functions which are normally in assembly files are
not included, but this should reduce the number of different undefined
references on the first few compiles from hundreds to 5 or 6
Given minimal startup code and console support it should be trivial to
make this compile and run the first few sysinits on almost any architecture.

Requested by: alfred, imp, jhb