sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

watchdog: clean up empty lines in .c and .h files

Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (17 of many)

r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly marked).
Use it in preparation for a general review of all nodes.

This is non-functional change that adds annotations to SYSCTL_NODE and
SYSCTL_PROC nodes using one of the soon-to-be-required flags.

Mark all obvious cases as MPSAFE. All entries that haven't been marked
as MPSAFE before are by default marked as NEEDGIANT

Approved by: kib (mentor, blanket)
Commented by: kib, gallatin, melifaro
Differential Revision: https://reviews.freebsd.org/D23718

Extract eventfilter declarations to sys/_eventfilter.h

This allows replacing "sys/eventfilter.h" includes with "sys/_eventfilter.h"
in other header files (e.g., sys/{bus,conf,cpu}.h) and reduces header
pollution substantially.

EVENTHANDLER_DECLARE and EVENTHANDLER_LIST_DECLAREs were moved out of .c
files into appropriate headers (e.g., sys/proc.h, powernv/opal.h).

As a side effect of reduced header pollution, many .c files and headers no
longer contain needed definitions. The remainder of the patch addresses
adding appropriate includes to fix those files.

LOCK_DEBUG and LOCK_FILE_LINE_ARG are moved to sys/_lock.h, as required by
sys/mutex.h since r326106 (but silently protected by header pollution prior
to this change).

No functional change (intended). Of course, any out of tree modules that
relied on header pollution for sys/eventhandler.h, sys/lock.h, or
sys/mutex.h inclusion need to be fixed. __FreeBSD_version has been bumped.

make SW_WATCHDOG dynamic

Enable the hardclock-based watchdog previously conditional on the
SW_WATCHDOG option whenever hardware watchdogs are not found, and
watchdogd attempts to enable the watchdog. The SW_WATCHDOG option
still causes the sofware watchdog to be enabled even if there is a
hardware watchdog. This does not change the other software-based
watchdog enabled by the --softtimeout option to watchdogd.

Note that the code to reprime the watchdog during kernel core dumps is
no longer conditional on SW_WATCHDOG. I think this was previously a bug.

Reviewed by: imp alfred bjk
MFC after: 1 week
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D13713

sys/dev: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Some cosmetic polishing for pre-timeouts.

MFC after: 1 week

CALLOUT_MPSAFE has lost its meaning since r141428, i.e., for more than ten
years for head. However, it is continuously misused as the mpsafe argument
for callout_init(9). Deprecate the flag and clean up callout_init() calls
to make them more consistent.

Differential Revision: https://reviews.freebsd.org/D2613
Reviewed by: jhb
MFC after: 2 weeks

Add a missing include of an options header.

watchdog.c does an #ifdef DDB but does not #include "opt_ddb.h".
Fixing this turned up a missing include file.

MFC after: 1 week
X-MFC-With: r261495, r279410

Use right buffer to print to.

PR: kern/176597
Submitted by: Christoph Mallon <christoph mallon gmx de>
MFC after: 2 weeks

Fix watchdog pretimeout.

The original API calls for pow2ns, however the new APIs from
Linux call for seconds.

We need to be able to convert to/from 2^Nns to seconds in both
userland and kernel to fix this and properly compare units.

watchdogd(8) and watchdog(4) enhancements.

The following support was added to watchdog(4):
- Support to query the outstanding timeout.
- Support to set a software pre-timeout function watchdog with an 'action'
- Support to set a software only watchdog with a configurable 'action'

'action' can be a mask specifying a single operation or a combination of:
log(9), printf(9), panic(9) and/or kdb_enter(9).

Support the following in watchdogged:
- Support to utilize the new additions to watchdog(4).
- Support to warn if a watchdog script runs for too long.
- Support for "dry run" where we do not actually arm the watchdog,
but only report on our timing.

Sponsored by: iXsystems, Inc.
MFC after: 1 month

- Add the possibility to reuse the already last used timeout when patting
the watchdog, via the watchdog(9) interface.
For that, the WD_LASTVAL bitwise operation is used. It is mutually
exclusive with any explicit timout passing to the watchdogs.
The last timeout can be returned via the wdog_kern_last_timeout()
KPI.
- Add the possibility to pat the watchdogs installed via the watchdog(9)
interface from the kernel.
In order to do that the new KPI wdog_kern_pat() is offered and it does
accept normalized nanoseconds or WD_LASTVAL.
- Avoid to pass WD_ACTIVE down in the watchdog handlers. All the control
bit processing should over to the upper layer functions and not passed
down to the handlers at all.

These changes are intended to be used in order to fix up the watchdog
tripping in situation when the userland is busted, but protection is still
wanted (examples: shutdown syncing / disk dumping).

Sponsored by: Sandvine Incorporated
Reviewed by: emaste, des, cognet
MFC after: 2 weeks

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

- Import the HEAD csup code which is the basis for the cvsmode work.

Revisit the watchdogs: Resetting the error to EINVAL after failing to set the
watchdog might hide the succesful arming of an earlier one. Accept that on
failing to arm any watchdog (because of non-supported timeouts) EOPNOTSUPP is
returned instead of the more appropriate EINVAL.

MFC after: 3 days

Align the interfaces for the various watchdogs and make the interface
behave as expected.

Also:
- Return an error if WD_PASSIVE is passed in to the ioctl as only
WD_ACTIVE is implemented at the moment. See sys/watchdog.h for an
explanation of the difference between WD_ACTIVE and WD_PASSIVE.
- Remove the I_HAVE_TOTALLY_LOST_MY_SENSE_OF_HUMOR define. If you've
lost your sense of humor, than don't add a define.

Specific changes:

i80321_wdog.c
Don't roll your own passive watchdog tickle as this would defeat the
purpose of an active (userland) watchdog tickle.

ichwd.c / ipmi.c:
WD_ACTIVE means active patting of the watchdog by a userland process,
not whether the watchdog is active. See sys/watchdog.h.

kern_clock.c:
(software watchdog) Remove a check for WD_ACTIVE as this does not make
sense here. This reverts r1.181.

Return zero when disabling watchdog, unless any of the drivers complain.

Do the dreaded s/dev_t/struct cdev */
Bump __FreeBSD_version accordingly.

Add a generic watchdog facility which through a single device entry
in /dev controls all available watchdog implementations.