atrtc(4): Fix a typo in a sysctl description

- s/emtpy/empty/

MFC after: 5 days

atrtc: Add a required include

PR: 275867
MFC after: 1 week

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

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

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spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

atrtc: expose power loss as sysctl

Exposing the a power loss of the rtc as an sysctl makes it easier to
detect an empty cmos battery.

Reviewed by: manu
MFC after: 1 week
Sponsored by: Beckhoff Automation GmbH & Co. KG
Differential Revision: https://reviews.freebsd.org/D38325

x86: Remove unused devclass arguments to DRIVER_MODULE.

atrtc: Install address space handler for \_SB and its descendant.

SystemCMOS address space is accessible for system wide.
So install address handler in \_SB space.

Reviewed by: jhb

Differential Revision: https://reviews.freebsd.org/D33892

atrtc: reads Century field from FADT table

The ACPI spec describes the FADT->Century field as:

The RTC CMOS RAM index to the century of data value (hundred and
thousand year decimals). If this field contains a zero, then the
RTC centenary feature is not supported. If this field has a non-zero
value, then this field contains an index into RTC RAM space that
OSPM can use to program the centenary field.

Use this field to decide whether to program the CENTURY register
of the CMOS RTC device.

Reviewed by: akumar3@isilon.com, dab, vangyzen
MFC after: 1 week
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D33667

MFC after: 1 week
Sponsored by: Dell EMC Isilon

x86: clean up empty lines in .c and .h files

Fix amd64/i386 LINT build after r344982

Submitted by: jkim
Reported by: rpokala
MFC with: r344982

atrtc(4): install ACPI RTC/CMOS operation region handler

FreeBSD base system does not provide an ACPI handler for the PC/AT RTC/CMOS
device with PnP ID PNP0B00; on some HP laptops, the absence of this handler
causes suspend/resume and poweroff(8) to hang or fail [1], [2]. On these
laptops EC _REG method queries the RTC date/time registers via ACPI
before suspending/powering off. The handler should be registered before
acpi_ec driver is loaded.

This change adds handler to access CMOS RTC operation region described in
section 9.15 of ACPI-6.2 specification [3]. It is installed only for ACPI
version of atrtc(4) so it should not affect old ACPI-less i386 systems.

It is possible to disable the handler with loader tunable:
debug.acpi.disabled=atrtc

Informational debugging printf can be enabled by setting hw.acpi.verbose=1
in loader.conf

[1] https://wiki.freebsd.org/Laptops/HP_Envy_6Z-1100
[2] https://wiki.freebsd.org/Laptops/HP_Notebook_15-af104ur
[3] https://uefi.org/sites/default/files/resources/ACPI_6_2.pdf

PR: 207419, 213039
Submitted by: Anthony Jenkins <Scoobi_doo@yahoo.com>
Reviewed by: ian
Discussed on: acpi@, 2013-2015, several threads
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D19314

Provide a helper function acpi_get_fadt_bootflags() to fetch the FADT
x86 boot flags.

Reviewed by: royger
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D16004
MFC after: 1 week

at_rtc: check in ACPI FADT boot flags if the RTC is present

Or else disable the device. Note that the detection can be bypassed by
setting the hw.atrtc.enable option in the loader configuration file.
More information can be found on atrtc(4).

Sponsored by: Citrix Systems R&D
Reviewed by: ian
Differential revision: https://reviews.freebsd.org/D14399

Give the atrtc_time_lock a unique name.

Reported by: hps@

Revert r330780, it was improperly tested and results in taking a spin
mutex before acquiring sleep mutexes.

Reported by: kib@

Remove MTX_NOPROFILE from atrtc_lock, it was inappropriately copy/pasted
from the i8254 driver when I created separate mutexes for each. The i8254
driver could be the active timecounter, leading to recursion during mutex
profiling, but the atrtc driver cannot be a timecounter, so it isn't needed.

Eliminate atrtc_time_lock, and use atrtc_lock for efirtc locking.

Everywhere that multiple registers are accessed in sequence, lock/unlock
just once around the whole group of accesses.

Use separate mutexes for atrtc and i8254 locking. Change all the strange
un-function-like RTC_LOCK/UNLOCK macro usage into normal function calls.
Since there is no longer any need to handle register access from a debugger
context, those function calls can just be regular mutex lock/unlock calls.

Requested by: bde

Convert atrtc the new style rtc debugging output. Remove the db show
command handler which provided much the same information. Removing the
possibility of accessing the hardware regs from the debugger context
paves the way for simplifying the locking code in the driver.

Add ISA PNP tables to ISA drivers. Fix a few incidental comments.
ACPI ISA PBP tables not tagged, there's bigger issues with them.

Remove redundant critical_enter/exit() calls. The block of code delimited
by these calls is now protected by a spin mutex (obscured within the
RTC_LOCK/RTC_UNLOCK macros).

Reported by: bde@

Move some code around and rename a couple variables; no functional changes.

The static atrtc_set() function was called only from clock_settime(), so
just move its contents entirely into clock_settime() and delete atrtc_set().

Rename the struct bcd_clocktime variables from 'ct' to 'bct'. I had
originally wanted to emphasize how identical the clocktime and bcd_clocktime
structs were, but things evolved to the point where the structs are not at
all identical anymore, so now emphasizing the difference seems better.

Add static inline rtcin_locked() and rtcout_locked() functions for doing a
related series of operations without doing a lock/unlock for each byte.
Use them when reading and writing the entire set of time registers.

The original rtcin() and writertc() functions which do lock/unlock on each
byte still exist, because they are public and called by outside code.

Convert the x86 RTC driver to use new validated BCD<->timespec conversions.

New common routines were added to kern/subr_clock.c for converting between
calendrical time expressed in BCD and struct timespec. The new functions
return EINVAL on error, as expected when the clock hardware does not provide
valid time.

PR: 224813
Differential Revision: https://reviews.freebsd.org/D13731 (no reviewers)

sys/x86: 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.

Stop calling atrtc_set() from the xen timer clock_settime() method. That
removes the only reference to atrtc_set() from outside of atrtc.c, so make
it static.

The xen timer driver registers as a realtime clock with 1us resolution. In
the past that resulted in only the xen timer's clock_settime() getting
called, so it would call atrtc_set() to set the hardware clock as well. As
of r32090, the clock_settime() method of all registered realtime clocks gets
called, so the xen driver no longer needs to chain-call the lower-resolution
driver.

Thanks to royger@ for talking me through the xen stuff, and for testing.

Protect access to the AT realtime clock with its own mutex.

The mutex protecting access to the registered realtime clock should not be
overloaded to protect access to the atrtc hardware, which might not even be
the registered rtc. More importantly, the resettodr mutex needs to be
eliminated to remove locking/sleeping restrictions on clock drivers, and
that can't happen if MD code for amd64 depends on it. This change moves the
protection into what's really being protected: access to the atrtc date and
time registers.

This change also adds protection when the clock is accessed from
xentimer_settime(), which bypasses the resettodr locking.

Differential Revision: https://reviews.freebsd.org/D11483

Validate values read from the RTC before trying BCD decoding

Submitted by: cem
Reported by: Michael Gmelin <freebsd@grem.de>
Tested by: Oleksandr Tymoshenko <gonzo@bluezbox.com>
Sponsored by: Dell EMC

atrtc: export function to set RTC

This is going to be used by the Xen clock on Dom0 in order to set the RTC of
the host. The current logic in atrtc_settime is moved to atrtc_set and the
unused device_t parameter is removed from the atrtc_set function call so it
can be safely used by other callers.

Sponsored by: Citrix Systems R&D
Reviewed by: kib, jhb
Differential revision: https://reviews.freebsd.org/D6067

Convert rman to use rman_res_t instead of u_long

Summary:
Migrate to using the semi-opaque type rman_res_t to specify rman resources. For
now, this is still compatible with u_long.

This is step one in migrating rman to use uintmax_t for resources instead of
u_long.

Going forward, this could feasibly be used to specify architecture-specific
definitions of resource ranges, rather than baking a specific integer type into
the API.

This change has been broken out to facilitate MFC'ing drivers back to 10 without
breaking ABI.

Reviewed By: jhb
Sponsored by: Alex Perez/Inertial Computing
Differential Revision: https://reviews.freebsd.org/D5075

Set the initial system time to a sane (as in: not end of 21st century) value when
booting on a PC with CMOS clock set to a year before 2000.

This uses 1980 (instead of 1970 as in the initial patch) as pivot year as
suggested by imp in the PR followup.

PR: 195703
Submitted by: cs@soi.spb.ru
Reviewed by: imp
MFC after: 1 weeks

MFcalloutng:
Switch eventtimers(9) from using struct bintime to sbintime_t.
Even before this not a single driver really supported full dynamic range of
struct bintime even in theory, not speaking about practical inexpediency.
This change legitimates the status quo and cleans up the code.

Use critical_enter/critical_exit around the time sensitive part of
this code to depessimize the worst case we've lived with silently and
uneventfully for the past 12 years. Add a comment about a refinement
for those needing more assurance of accuracy.

Fix ddb's show rtc command deadlock potential when debugging rtc code
by not taking the lock if we're in the debugger. If you need a thumb
to count the number of people that have encountered this, I'd be
surprised.

Submitted by: bde

Fix broken usage of splhigh() by removing it.

Small style fixes:
- Avoid side-effect assignments in if statements when possible.
- Don't use ! to check for NULL pointers, explicitly check against NULL.
- Explicitly check error return values against 0.
- Don't use INTR_MPSAFE for interrupt handlers with only filters as it is
meaningless.
- Remove unneeded function casts.

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

atrtc: remove (pre-)historic check of RTC NVRAM at address 0x0e

Old scrolls tell that once upon a time IBM AT BIOS was known to put some
useful system diagnostic information into RTC NVRAM. It is not really
known if and for how long PC BIOSes followed that convention, but I
believe that many, if not all, modern BIOSes do not do that any more
(not mentioning other types of x86 firmware).
Some diagnostic bits don't even make any sense any longer.
The check results in confusing messages upon boot on some systems.
So I am removing it.

Discussed with: bde, jhb, mav
MFC after: 3 weeks

Fix several un-/signedness bugs of r210290 and r210293. Add one more check.

Extend timer driver API to report also minimal and maximal supported period
lengths. Make MI wrapper code to validate periods in request. Make kernel
clock management code to honor these hardware limitations while choosing hz,
stathz and profhz values.

Rise knowledge about curthread->td_intr_frame by one step. Make timer
callback argument really opaque. Not repeat interrupt handler's problem
in case somebody will ever need to have both argument and frame.

Instead of deleting existing IRQ resource, which is not really working for
ACPI bus, find wanted IRQ rid or spare one. This should fix panic during
boot on systems reporting fancy IRQ numbers for attimer and atrtc.

Allow attimer to be hinted at ISA if not reported by ISA PNP or ACPI.
Rephrase respective atrtc code same way to be more readable.

Rework r209456:
Instead of using fake rid (which ISA doesn't like), delete untrusted
IRQ resource and let it be recreated.

Do not trust IRQ reported by ACPI. There are cases when it is wrong.

Add "legacy route" support to HPET driver. When enabled, this mode makes
HPET to steal IRQ0 from i8254 and IRQ8 from RTC timers. It can be suitable
for HPETs without FSB interrupts support, as it gives them two unshared
IRQs. It allows them to provide one per-CPU event timer on dual-CPU system,
that should be suitable for further tickless kernels.

To enable it, such lines may be added to /boot/loader.conf:
hint.atrtc.0.clock=0
hint.attimer.0.clock=0
hint.hpet.0.legacy_route=1

Fix i386 LINT build broken by r209371.
There appeared such legacy thing as APM, that somehow breaking RTC.

Implement new event timers infrastructure. It provides unified APIs for
writing event timer drivers, for choosing best possible drivers by machine
independent code and for operating them to supply kernel with hardclock(),
statclock() and profclock() events in unified fashion on various hardware.

Infrastructure provides support for both per-CPU (independent for every CPU
core) and global timers in periodic and one-shot modes. MI management code
at this moment uses only periodic mode, but one-shot mode use planned for
later, as part of tickless kernel project.

For this moment infrastructure used on i386 and amd64 architectures. Other
archs are welcome to follow, while their current operation should not be
affected.

This patch updates existing drivers (i8254, RTC and LAPIC) for the new
order, and adds event timers support into the HPET driver. These drivers
have different capabilities:
LAPIC - per-CPU timer, supports periodic and one-shot operation, may
freeze in C3 state, calibrated on first use, so may be not exactly precise.
HPET - depending on hardware can work as per-CPU or global, supports
periodic and one-shot operation, usually provides several event timers.
i8254 - global, limited to periodic mode, because same hardware used also
as time counter.
RTC - global, supports only periodic mode, set of frequencies in Hz
limited by powers of 2.

Depending on hardware capabilities, drivers preferred in following orders,
either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC.
User may explicitly specify wanted timers via loader tunables or sysctls:
kern.eventtimer.timer1 and kern.eventtimer.timer2.
If requested driver is unavailable or unoperational, system will try to
replace it. If no more timers available or "NONE" specified for second,
system will operate using only one timer, multiplying it's frequency by few
times and uing respective dividers to honor hz, stathz and profhz values,
set during initial setup.

Introduce the new kernel sub-tree x86 which should contain all the code
shared and generalized between our current amd64, i386 and pc98.

This is just an initial step that should lead to a more complete effort.
For the moment, a very simple porting of cpufreq modules, BIOS calls and
the whole MD specific ISA bus part is added to the sub-tree but ideally
a lot of code might be added and more shared support should grow.

Sponsored by: Sandvine Incorporated
Reviewed by: emaste, kib, jhb, imp
Discussed on: arch
MFC: 3 weeks