Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Revert bogus part of r241740.
Reported by: Michael Moll

MFC after: 3 days

- Remove an unused header.
- Don't waste a delay slot.

MFC after: 3 days

UltraSPARC-IV CPUs seem to be affected by a not publicly documented
erratum causing them to trigger stray vector interrupts accompanied by a
state in which they even fault on locked TLB entries. Just retrying the
instruction in that case gets the CPU back on track though. OpenSolaris
also just ignores a certain number of stray vector interrupts.
While at it, implement the stray vector interrupt handling for SPARC64-VI
which use these for indicating uncorrectable errors in interrupt packets.

Add a hack for SPARC64 V CPUs, which set some undocumented bits in the
first data word.

Don't use an out register to hold the vector number across the call
of the interrupt handler in intr_fast() as the handler might clobber
it (no in-tree handler currently does but an upcoming one will).
While at it, tidy the register usage in the interrupt counting code.

Convert the remainder of the low hanging fruits regarding including
headers in .S directly rather than getting to their macros through
genassym.c/assym.s so there are less headers genassym.c has to be
kept in sync with.
While at it fix some stytle(9) bugs (indentation, prototype format,
sort headers, etc) and remove trailing whitespace.

- Since critical sections no longer raise the processor interrupt level to
above what's used for fast interrupts, only interrupts with the level of
the interrupt which led to calling intr_fast() (which is used with both
fast and ithread interrupts) are blocked while in that function. Thus
intr_fast() can be preempted by a fast interrupt (which are of a higher
level than ithread interrupts) while servicing an ithread interrupt. This
can lead to a stale pointer to the head of the active interrupt requests
list when back in the ithread interrupt invocation of intr_fast(), in turn
resulting in corruption of the interrupt request lists and consequently
in a panic. Solve this be turning off interrupts in intr_fast() before
reading the pointer to the head of the active list rather than after. [1]
- Add a KASSERT in intr_fast() which asserts that ir_func is non-zero before
calling it. [1]
- Increment interrupt stats after calling the handlers rather than before.
This reduces the delay until direct and fast handlers are serviced, in my
testings by 30% on average for the direct tick interrupt handler, in turn
resulting in less clock drift.

PR: 94778 [1]
Submitted by: Andrew Belashov [1]
MFC after: 2 weeks

- MFi386: sys/i386/i386/intr_machdep.c rev. 1.11
Don't use atomic ops to increment interrupt stats.
On sparc64 this reduces delay until tick interrupts are service by 1/10th
on average. In turn this reduces the clock drift caused by these delays
so there's less drift which has to be compensated in tick_hardclock().
This includes switching from atomically incrementing the global cnt.v_intr
to the asm equivalent of PCPU_LAZY_INC(cnt.v_intr) in exception.S
- Correct some comments to match the registers actually used.
- Correct some format specifiers, interrupt levels passed in are u_int.
- Use FBSDID.

Ok'ed by: jhb

add support for interrupt counting on sparc64. This copies part of the
code from i386. The code has a slight bogon that interrupts are counted
twice. Once on the ithread dispatch and once on the dispatch for the vector

vmstat -i and systat -vm now contains interrupt counts.

Reviewed by: jake

- Fix placement of cvs ids in previous commit to match .S files in libc.
- gcc uses 32 byte alignment for functions regardless of profiling, so
follow suit.

I was wrong, the ENTRY bits in asm.h did have a purpose -- for userland.
Restore the bits and remove them from asmacros.h. *.S will now be asm.h
consumers.

Approved by: jake

Correct typos, mostly s/ a / an / where appropriate. Some whitespace cleanup,
especially in troff files.

Use the meaningful mnemonics for ancillary state registers now that gas
is invoked properly to understand them.

%asr19 -> %gsr
%asr20 -> %set_softint
%asr21 -> %clear_softint

Renamed intr_enqueue to intr_vector and intr_dequeue to intr_fast, to
better reflect how they are called.

Moved most interrupt related code to a new file, interrupt.S.