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 bits for userland profiling. For sun4u this is compile-tested only.
- Replace magic 14 with PIL_TICK.

/* -> /*- for license, minor formatting changes

Move the kernel-specific logic to adjust frompc from MI to MD. For
these two reasons:
1. On ia64 a function pointer does not hold the address of the first
instruction of a functions implementation. It holds the address
of a function descriptor. Hence the user(), btrap(), eintr() and
bintr() prototypes are wrong for getting the actual code address.
2. The logic forces interrupt, trap and exception entry points to
be layed-out contiguously. This can not be achieved on ia64 and is
generally just bad programming.

The MCOUNT_FROMPC_USER macro is used to set the frompc argument to
some kernel address which represents any frompc that falls outside
the kernel text range. The macro can expand to ~0U to bail out in
that case.
The MCOUNT_FROMPC_INTR macro is used to set the frompc argument to
some kernel address to represent a call to a trap or interrupt
handler. This to avoid that the trap or interrupt handler appear to
be called from everywhere in the call graph. The macro can expand
to ~0U to prevent adjusting frompc. Note that the argument is selfpc,
not frompc.

This commit defines the macros on all architectures equivalently to
the original code in sys/libkern/mcount.c. People can take it from
here...

Compile-tested on: alpha, amd64, i386, ia64 and sparc64
Boot-tested on: i386

Moved most of the "MI" definitions and declarations from <machine/profile.h>
to <sys/gmon.h>. Cleaned them up a little by not attempting to ifdef
for incomplete and out of date support for GUPROF in userland, as in
the sparc64 version.

Add definitions for statistical and high-resolution profiling. The calling
conventions for _mcount and __cyg_profile_func_enter are different, so
statistical profiling kernels build and link but don't actually work.
IWBNI one could tell gcc to only generate calls to the former.

Define uintfptr_t properly for userland, but not for the kernel (I hope).

Revert the previous delta; uintfptr_t needs to be available to
userland for libc/gmon to compile, so the typedef in <machine/types.h>
isn't good enough. This is really ugly since we end up with the
actual value which uintfptr_t is typedef'd from, in multiple places.
This is bug for bug compatible with the other FreeBSD architectures.

Noticed by: sparc64 tinderbox

uintfptr_t has moved to machine/types.h.

Remove a couple of __P() stragglers.

Add kernel headers needed to build libc. Some are bogus and/or just enough
to compile.

Mostly obtained from: netbsd