bring the section on automatic acquisition of kernel_lock up-to-date

branches: 1.41.12;
Expand on previous, and note that splnet() and spltty() are also synonyms
for splvm().

Document splbio() as a deprecated synonym for splvm().

branches: 1.39.2; 1.39.30; 1.39.34;
kpreempt(9): add a note when kernel preemption is disabled/deferred.
Sprinkle cross-links, bump dates.

Xref i386/splraise.9 and bump date for previous.

Move MD spllower(9) and splraise(9) doco from the MI spl(9) to an i386
manual page.

Remove trailing space. Remove unnecessary Pp before Sh.

Describe spllower(9) and splraise(9).

Fix xrefs. Drop trailing whitespace. Use Dq.

Fix typo(s/interupt/interrupt/)

branches: 1.32.12;
Fix some pastos.

Typo: muliprocessor -> multiprocessor

Typo: indepenent -> independent

Typo: higest -> highest

sys/param.h ???

Sync with reality.

branches: 1.26.4;
Fix Dd argument.

Note that device drivers should not (in general) use these interfaces.

Bump date for previous.

PR# 34288: No splaudio() in man 9 spl, from Stephane Witzmann.

a header actually used for spl functions is sys/param.h, not machine/intr.h.

Use
.In header.h
instead of
.Fd #include \*[Lt]header.h\*[Gt]
Much easier to read and write, and supported by groff for ages.
Okayed by ross.

New sentence, new line.

Use .Nm instead of Xref to ourselves.

Add a paragraph about splsoftnet()/splnet(), which often seems to confuse
people coming from FreeBSD.

Generate <>& symbolically. I'm avoiding .../dist/... directories for now.

Drop some .Pps.

Boring whitespace fixes.

Move splched() prototype under splserial() in SYNOPSYS, so that the
entries are sorted by priority correctly.

add splvm() to NAME section

Update to reflect reality.

Document spllock().

Fix two more typos.

i before e except after c ...

Inject more truth into this document.

IPL-lowering functions are now defined to return `void.' See also my
post to tech-kern about the issue. No ports updated yet; they should
be updated as time permits.

branches: 1.6.2;
semantics of splclock() were changed, and spllowersoftclock() was introduced
on the following commit (thanks Frank van der Linden, Steve Woodford
and Alistair G. Crooks for english correction of HISTORY section):

date: 1999/08/05 18:08:10; author: thorpej; state: Exp; lines: +3 -2

Change the semantics of splsoftclock() to be like other spl*() functions,
that is priority is rasied. Add a new spllowersoftclock() to provide the
atomic drop-to-softclock semantics that the old splsoftclock() provided,
and update calls accordingly.

This fixes a problem with using the "rnd" pseudo-device from within
interrupt context to extract random data (e.g. from within the softnet
interrupt) where doing so would incorrectly unblock interrupts (causing
all sorts of lossage).

More .Os cleanups. .Os is defined in the tmac.doc-common file,
so we shouldn't override it with versions in the manpages. Many more to
come.

spl*() functions block interrupts of lesser or equal priority, not
higher priority. do some copy editing while I'm here.

add missing .Nm sections

branches: 1.2.2;
remove advertising clause from license

add incomplete spl(9); realphabetize Makefile.