sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\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spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

cpufreq(4): Add support for Intel Speed Shift

Intel Speed Shift is Intel's technology to control frequency in hardware,
with hints from software.

Let's get a working version of this in the tree and we can refine it from
here.

Submitted by: bwidawsk, scottph
Reviewed by: bcr (manpages), myself
Discussed with: jhb, kib (earlier versions)
With feedback from: Greg V, gallatin, freebsdnewbie AT freenet.de
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D18028

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.

Introduce PMCR-based cpufreq(4) driver, for IBM POWER8 and POWER9 systems

Summary: POWER8 and POWER9 use a single CPU register, per core, to change clock
speed. Everything else is handled by the on-chip controller. This change
necessitates a change to the cpufreq global kernel driver to bump supported
levels, as the device tree for these systems can have theoretically 256
different options. On my POWER9 Talos, the list consists of 100 items. At
16.67MHz intervals, that allows for a change of roughly 1.67GHz between lowest
and highest.

This has only been tested on the POWER9. However, since they're similar, this
should work on POWER8 as well.

Reviewed By: nwhitehorn
Differential Revision: https://reviews.freebsd.org/D15932

sys/sys: 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.

Add support to get the cpu ID from its device driver in a generic way.
This will be needed by arm64 to find the value to pass to the psci (Power
State Coordination Interface) driver, among other things, used to enable
cores.

Differential Revision: https://reviews.freebsd.org/D1824
Reviewed by: imp
Sponsored by: The FreeBSD Foundation

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

Provide a new CPU device driver ivar to report the nominal speed of the
CPU, if available. This is meant to solve the issue of cpufreq misreporting
speeds on CPUs that boot in a reduced power mode and have only relative
speed control.

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

Add an interface for drivers to be notified of changes to CPU frequency.
cpufreq_pre_change is called before the change, giving each driver a chance
to revoke the change. cpufreq_post_change provides the results of the
change (success or failure). cpufreq_levels_changed gives the unit number
of the cpufreq device whose number of available levels has changed. Hook
in all the drivers I could find that needed it.

* TSC: update TSC frequency value. When the available levels change, take the
highest possible level and notify the timecounter set_cputicker() of that
freq. This gets rid of the "calcru: runtime went backwards" messages.
* identcpu: updates the sysctl hw.clockrate value
* Profiling: if profiling is active when the clock changes, let the user
know the results may be inaccurate.

Reviewed by: bde, phk
MFC after: 1 month

Add a new field to struct cf_setting for special values. These are driver-
specific values that other components may want to use. Add support to
acpi_perf(4) to export the control and status values via this field.

Add the new CPUFREQ_FLAG_INFO_ONLY flag for drivers which can attach to
read info about the possible settings for a CPU but cannot control them
directly.

Add a new include to handle generic CPU interfaces.