Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

MFC r263815, r263872:

Move ia64 efi.h to sys in preparation for amd64 UEFI support

Prototypes specific to ia64 have been left in this file for now, under
__ia64__, rather than moving them to a new header under sys/ia64.
I anticipate that (some of) the corresponding functions will be shared
by the amd64, arm64, i386, and ia64 architectures, and we can adjust
this as EFI support on other than ia64 continues to develop.

Fix missed efi.h header change in r263815

Sponsored by: The FreeBSD Foundation

MFC r263248 & r263257: In intr_event_handle() we already save and set
td_intr_frame, so don't do it also in ia64_handle_intr().

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

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.

Don't send EOI to the CPU before we handled the interrupt. This could
potentially trigger multiple pending interrupts for level-sensitive
interrupts. However, the event timer interrupt does need EOI before
being handled to avoid missing clock events.

These conflicting requirements are handled by having the XIV handler
inform the dispatch code whether or not it send EOI to the CPU. If not,
the dispatch code will do it. This allows handlers to send EOI before
doing potentially long-running activities, while still have a sensible
default behaviour.

Oops. The sec field of struct bintime is *not* a 32-bit type.
It's time_t, which is 64 bits on ia64.

Define the minimum fractional period in terms of hz. We know hz is
a magnitude smaller than itc_freq. A minimum period of 10*hz is
sufficient precision. As a side-effect, the number of clocks per
second, when the machine is idle, dropped by more than 50%.
Be anal and define the maximum period to be at least 4G seconds.
With a 64-bit counter and an ITC frequency that's expected to be
always less than 4Ghz, it takes longer than that to wrap around.

Update copyright.

Switch to the event timers infrastructure. This includes:
o Setting td_intr_frame to the XIVs trap frame because it's referenced
by the ET event handler.
o Signal EOI to the CPU before calling the registered XIV handlers.
This prevents lost ITC interrupts, which cause starvation in one-shot
mode.
o Adding support for IPI_HARDCLOCK with corresponding per-CPU counters.
o Have the APs call cpu_initclocks() so as to limited the scattering of
clock related initialization. cpu_initclocks() calls the <self>_bsp()
or <self>_ap() version accordingly.
o Uncomment the ET clock handling in cpu_idle().
o Update the DDB 'show pcpu' output for the new MD fields.
o Entirely rewritten ia64_ih_clock(). Note that we don't create as many
clock XIVs as we have CPUs, as is done on PowerPC. It doesn't scale.
We can only have 240 XIVs and we can have more CPUs than that. There's
a single intrcnt index for the cumulative clock ticks and we keep per
CPU counts in the PCPU stats structure.
o Register the ITC by hooking SI_SUB_CONFIGURE (2nd order).

Open issues:
o Clock interrupts can still be lost. Some tweaking is still necessary.

Thanks to: mav@ for his support, feedback and explanations.

ET stats while committing:
eris% sysctl machdep.cpu | grep nclks

machdep.cpu.0.nclks: 24007
machdep.cpu.1.nclks: 22895
machdep.cpu.2.nclks: 13523
machdep.cpu.3.nclks: 9342
machdep.cpu.4.nclks: 9103
machdep.cpu.5.nclks: 9298
machdep.cpu.6.nclks: 10039
machdep.cpu.7.nclks: 9479
eris% vmstat -i | grep clock
clock 108599 50

Only use the interval timer for clock interrupts on the BSP and
have the BSP use IPIs to trigger clock interrupts on the APs.
This allows us to run on hardware configurations for which the
ITC has non-uniform frequencies across CPUs.

While here, change the clock XIV to type IPI so as to protect
the interrupt delivery against CPU re-balancing once that's
implemented.

Fix interrupt handling by extending the critical region so that
preemption doesn't happen until after all pending interrupt have
been services.
While here again, simplify the EOI handling by doing it after we
call the XIV-specific handlers, rather than in each of them. The
original thought was that we may want to do an EOI first and the
actual IPI handling next, but that's mostly a micro-optimization.

Revamp the interrupt code based on the previous commit:
o Introduce XIV, eXternal Interrupt Vector, to differentiate from
the interrupts vectors that are offsets in the IVT (Interrupt
Vector Table). There's a vector for external interrupts, which
are based on the XIVs.

o Keep track of allocated and reserved XIVs so that we can assign
XIVs without hardcoding anything. When XIVs are allocated, an
interrupt handler and a class is specified for the XIV. Classes
are:
1. architecture-defined: XIV 15 is returned when no external
interrupt are pending,
2. platform-defined: SAL reports which XIV is used to wakeup
an AP (typically 0xFF, but it's 0x12 for the Altix 350).
3. inter-processor interrupts: allocated for SMP support and
non-redirectable.
4. device interrupts (i.e. IRQs): allocated when devices are
discovered and are redirectable.

o Rewrite the central interrupt handler to call the per-XIV
interrupt handler and rename it to ia64_handle_intr(). Move
the per-XIV handler implementation to the file where we have
the XIV allocation/reservation. Clock interrupt handling is
moved to clock.c. IPI handling is moved to mp_machdep.c.

o Drop support for the Intel 8259A because it was broken. When
XIV 0 is received, the CPU should initiate an INTA cycle to
obtain the interrupt vector of the 8259-based interrupt. In
these cases the interrupt controller we should be talking to
WRT to masking on signalling EOI is the 8259 and not the I/O
SAPIC. This requires adriver for the Intel 8259A which isn't
available for ia64. Thus stop pretending to support ExtINTs
and instead panic() so that if we come across hardware that
has an Intel 8259A, so have something real to work with.

o With XIVs for IPIs dynamically allocatedi and also based on
priority, define the IPI_* symbols as variables rather than
constants. The variable holds the XIV allocated for the IPI.

o IPI_STOP_HARD delivers a NMI if possible. Otherwise the XIV
assigned to IPI_STOP is delivered.

Export the bus, cpu and itc frequencies under the hw.freq sysctl node.
The frequencies are in MHz (i.e. a value of 1000 represents 1GHz). The
frequencies are rounded to the nearest whole MHz.

While here, rename and re-type bus_frequency, processor_frequency and
itc_frequency to bus_freq, cpu_freq and itc_freq and make them static.
As unsigned integers, the hw.freq.cpu sysctl can more easily be made
generic (across all architectures) making porting easier.

MFC after: 3 days

Define struct pcpu_md as the only MD field of struct pcpu (pc_acpi_id
excluded, as it's used by MI code) and mode the sysctl variables from
pcpu_stats to pcpu_md.
Adjust all references accordingly.

While nearby, change the PCPU sysctl tree so that they match the CPU
device sysctl tree -- they are now children of a static node called
"machdep.cpu" and are named only with their cpu ID.

Now that all platforms use genclock, shuffle things around slightly
for better structure.

Much of this is related to <sys/clock.h>, which should really have
been called <sys/calendar.h>, but unless and until we need the name,
the repocopy can wait.

In general the kernel does not know about minutes, hours, days,
timezones, daylight savings time, leap-years and such. All that
is theoretically a matter for userland only.

Parts of kernel code does however care: badly designed filesystems
store timestamps in local time and RTC chips almost universally
track time in a YY-MM-DD HH:MM:SS format, and sometimes in local
timezone instead of UTC. For this we have <sys/clock.h>

<sys/time.h> on the other hand, deals with time_t, timeval, timespec
and so on. These know only seconds and fractions thereof.

Move inittodr() and resettodr() prototypes to <sys/time.h>.
Retain the names as it is one of the few surviving PDP/VAX references.

Move startrtclock() to <machine/clock.h> on relevant platforms, it
is a MD call between machdep.c/clock.c. Remove references to it
elsewhere.

Remove a lot of unnecessary <sys/clock.h> includes.

Move the machdep.disable_rtc_set sysctl to subr_rtc.c where it belongs.
XXX: should be kern.disable_rtc_set really, it's not MD.

Use genclock for RTC handling. This eliminates the MD versions for
inittodr() and resettodr(). Have nexus double as the clock device,
because it's the firmware that provides RTC services. We could
create a special (pseudo-) device for it, but that wasn't superior
enough to actually do it. Maybe later...

Requested by: phk

Add required data-serialization after writing to cr.itm and cr.itv.

Approved by: re (blanket)

If clock_ct_to_ts fails to convert time time from the real time clock,
print a one line error message. Add some comments on not being able to
trust the day of week field (I'll act on these comments in a follow up
commit).

Approved by: re
MFC after: 3 weeks

Fix previous revision:
o day and mday are the same. No need to subtract 1 from mday.
o Set dow to -1 as clock_ct_to_ts() checks this field and
returns EINVAL on any day of the week but Sunday.

Use calendrical calculations from subr_clock.c instead of home-rolled.

Second part of a little cleanup in the calendar/timezone/RTC handling.

Split subr_clock.c in two parts (by repo-copy):
subr_clock.c contains generic RTC and calendaric stuff. etc.
subr_rtc.c contains the newbus'ified RTC interface.

Centralize the machdep.{adjkerntz,disable_rtc_set,wall_cmos_clock}
sysctls and associated variables into subr_clock.c. They are
not machine dependent and we have generic code that relies on being
present so they are not even optional.

First part of a little cleanup in the calendar/timezone/RTC handling.

Move relevant variables to <sys/clock.h> and fix #includes as necessary.

Use libkern's much more time- & spamce-efficient BCD routines.

Remove more straggling CPU_ macro references

Sanity the RTC code:
o Remove the clock interface. Not only does it conflict with the MI
version when device genclock is added to the kernel, it was also
not possible to have more than 1 clock device. This of course would
have been a problem if we actually had more than 1 clock device.
In short: we don't need a clock interface and if we do eventually,
we should be using the MI one.
o Rewrite inittodr() and resettodr() to take into account that:
1) We use the EFI interface directly.
2) time_t is 64-bit and we do need to make sure we can determine
leap years from year 2100 and on. Add a nice explanation of
where leap years come from and why.
3) This rewrite happened in 2005 so any date prior to 1/1/2005
(either M/D/Y or D/M/Y) is bogus. Reprogram the EFI clock with
1/1/2005 in that case.
4) The EFI clock has a high probability of being correct, so
only (further) correct the EFI clock when the file system time
is larger. That should never happen in a time-synchronised world.
Complain when EFI lost 2 days or more.

Replace the copyright notice now that I (pretty much) rewrote all of
this file.

/* -> /*- for copyright notices, minor format tweaks as necessary

Remove advertising clause from University of California Regent's
license, per letter dated July 22, 1999 and email from Peter Wemm,
Alan Cox and Robert Watson.

Approved by: core, peter, alc, rwatson

Cleanup the clock code. This includes:
o Remove alpha specific timer code (mc146818A) and compiled-out
calibration of said timer.
o Remove i386 inherited timer code (i8253) and related acquire and
release functions.
o Move sysbeep() from clock.c to machdep.c and have it return
ENODEV. Console beeps should be implemented using ACPI or if no
such device is described, using the sound driver.
o Move the sysctls related to adjkerntz, disable_rtc_set and
wall_cmos_clock from machdep.c to clock.c, where the variables
are.
o Don't hardcode a hz value of 1024 in cpu_initclocks() and don't
bother faking a stathz that's 1/8 of that. Keep it simple: hz
defaults to HZ and stathz equals hz. This is also how it's done
for sparc64.
o Keep a per-CPU ITC counter (pc_clock) and adjustment (pc_clockadj)
to calculate ITC skew and corrections. On average, we adjust the
ITC match register once every ~1500 interrupts for a duration of
2 consequtive interruprs. This is to correct the non-deterministic
behaviour of the ITC interrupt (there's a delay between the match
and the raising of the interrupt).
o Add 4 debugging sysctls to monitor clock behaviour. Those are
debug.clock_adjust_edges, debug.clock_adjust_excess,
debug.clock_adjust_lost and debug.clock_adjust_ticks. The first
counts the individual adjustment cycles (when the skew first
crosses the threshold), the second counts the number of times the
adjustment was excessive (any non-zero value is to be considered
a bug), the third counts lost clock interrupts and the last counts
the number of interrupts for which we applied an adjustment
(debug.clock_adjust_ticks / debug.clock_adjust_edges gives the
avarage duration of an individual adjustment -- should be ~2).

While here, remove some nearby (trivial) left-overs from alpha and
other cleanups.

Rename the "IA64 ITC" counter to "ITC" counter. We don't call the
"TSC" counter on i386 "I386 TSC".

Approved by: re@ (blanket)

Split statclock into statclock and profclock, and made the method for driving
statclock based on profhz when profiling is enabled MD, since most platforms
don't use this anyway. This removes the need for statclock_process, whose
only purpose was to subdivide profhz, and gets the profiling clock running
outside of sched_lock on platforms that implement suswintr.
Also changed the interface for starting and stopping the profiling clock to
do just that, instead of changing the rate of statclock, since they can now
be separate.

Reviewed by: jhb, tmm
Tested on: i386, sparc64

Replace the hardcoding of 255 as the clock interrupt vector with
CLOCK_VECTOR and define it as 254, not 255. Vector 255 is already
in use as the AP wakeup vector on the HP rx2600.

This needs to be made more dynamic. The likelyhood of vector 254
being in use is pretty small, but we already have code to assign
vectors to IPIs (see sal.c) and it's preobably better to have a
centralized "vector manager" that hands out vectors based on
some imput (like priority).

Manually inline handleclock(). There's only a single caller and
handleclock itself is trivial.

While here, replace (itc_frequency+hz/2)/hz with itm_reload for
consistency. There's now a single place where we determine the
ITM reload value.

Do not assume that time_t is an int.

Approved by: re (jhb)

Do a bit of rude hackery to get clock interrupts on all CPUs. This
is partly based on the Alpha system which duplicates the clock to
each cpu, instead of doing a clock roundrobin like on i386. This means
we get hz * ncpu clocks per second and so we have to seperate clock
sampling from actual 'do the work' clock processing. The BSP runs the
complete processing, the rest just sample state etc.

Using the on-cpu interval timer is not ideal as it will drift. There
is more to be done here, we should use an external clock source.

More s/file system/filesystem/g

Don't export timecounter structures under debug. with sysctl, they
contain no truly interesting data anymore.

Turn off the ia64 ITC timecounter when SMP is present since it has the
same problem as the TSC on the x86 - ie: it is not synchronized.
#if 0 out some unused functions, ia64 doesn't calibrate clocks yet.

Make the clock vector 255 instead of 240. On Lion boxes, 240 is
the AP wake-up vector. We probably want a more dynamic approach
to assigning vectors in the future...

* Don't pretend the object passed to clockattach is a device - it isn't.
* Declare itc_frequency properly.

Various changes to use the firmware on a real machine.

* Enable dynamically linked kernel. This involves adding a self-relocator
to locore to process the @fptr relocations in the dynamic executable.
* Don't initialise the timer until *after* we install the timecounter to
avoid a race between timecounter initialisation and hardclock.
* Tidy up bootinfo somewhat including adding sanity checks for when the
kernel is loaded without a recognisable bootinfo.

Minor build fixes.

* Various fixes to breakage introduced by the atomic and mutex reorgs.
* Fixes to the signal delivery code. Not quite right yet.

I would have preferred to wait until I have signal delivery actually
working but the current kernel in CVS doesn't build.

Decrease the number of ticks between clock interrupts by a factor of ten
to place more pressure on the exception handling code.

Remember to re-initialise cr.itm on clock interrupts so that we get more
than just one tick.

Implement a rudimentary interrupt handling system which should be good
enough for clock interrupts in SKI.

Next round of fixes to the ia64 code. This includes simulated clock and
disk drivers along with a load of fixes to context switching, fork
handling and a load of other stuff I can't remember now. This takes us as
far as start_init() before it dies. I guess now I will have to finish off
the VM system and syscall handling :-).

Next round of ia64 work, including fixes to context switching,
implementing cpu_fork(), copy*str(), bcopy(), copy{in,out}(). With these
changes, my test kernel reaches the mountroot prompt.

This is the first snapshot of the FreeBSD/ia64 kernel. This kernel will
not work on any real hardware (or fully work on any simulator). Much more
needs to happen before this is actually functional but its nice to see
the FreeBSD copyright message appear in the ia64 simulator.