- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

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

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

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

- Remove the eintrcnt/eintrnames usage and introduce the concept of
sintrcnt/sintrnames which are symbols containing the size of the 2
tables.
- For amd64/i386 remove the storage of intr* stuff from assembly files.
This area can be widely improved by applying the same to other
architectures and likely finding an unified approach among them and
move the whole code to be MI. More work in this area is expected to
happen fairly soon.

No MFC is previewed for this patch.

Tested by: pluknet
Reviewed by: jhb
Approved by: re (kib)

- Merge changes to the base system to support OFED. These include
a wider arg2 for sysctl, updates to vlan code, IFT_INFINIBAND,
and other miscellaneous small features.

Remove 'softclock_ih' as it is no longer used.

- Fix several off-by-one errors when using MAXCOMLEN. The p_comm[] and
td_name[] arrays are actually MAXCOMLEN + 1 in size and a few places that
created shadow copies of these arrays were just using MAXCOMLEN.
- Prefer using sizeof() of an array type to explicit constants for the
array length in a few places.
- Ensure that all of p_comm[] and td_name[] is always zero'd during
execve() to guard against any possible information leaks. Previously
trailing garbage in p_comm[] could be leaked to userland in ktrace
record headers via td_name[].

Reviewed by: bde

Properly sort the intr_event_describe_handler() prototype.

Submitted by: bde

Add a facility for associating optional descriptions with active interrupt
handlers. This is primarily intended as a way to allow devices that use
multiple interrupts (e.g. MSI) to meaningfully distinguish the various
interrupt handlers.
- Add a new BUS_DESCRIBE_INTR() method to the bus interface to associate
a description with an active interrupt handler setup by BUS_SETUP_INTR.
It has a default method (bus_generic_describe_intr()) which simply passes
the request up to the parent device.
- Add a bus_describe_intr() wrapper around BUS_DESCRIBE_INTR() that supports
printf(9) style formatting using var args.
- Reserve MAXCOMLEN bytes in the intr_handler structure to hold the name of
an interrupt handler and copy the name passed to intr_event_add_handler()
into that buffer instead of just saving the pointer to the name.
- Add a new intr_event_describe_handler() which appends a description string
to an interrupt handler's name.
- Implement support for interrupt descriptions on amd64 and i386 by having
the nexus(4) driver supply a custom bus_describe_intr method that invokes
a new intr_describe() MD routine which in turn looks up the associated
interrupt event and invokes intr_event_describe_handler().

Requested by: many
Reviewed by: scottl
MFC after: 2 weeks

Tweak some comments.

Expose a new public routine intr_event_execute_handlers() which executes
all the non-filter handlers attached to an interrupt event. This can be
used by device drivers which multiplex their interrupt onto the interrupt
handlers for child devices.

revert changes accidentally included in last commit

import vendor fixes to cxgb

- Add the interrupt vector number to intr_event_create so MI code can
lookup hard interrupt events by number. Ignore the irq# for soft intrs.
- Add support to cpuset for binding hardware interrupts. This has the
side effect of binding any ithread associated with the hard interrupt.
As per restrictions imposed by MD code we can only bind interrupts to
a single cpu presently. Interrupts can be 'unbound' by binding them
to all cpus.

Reviewed by: jhb
Sponsored by: Nokia

Add a MI intr_event_handle() routine for the non-INTR_FILTER case. This
allows all the INTR_FILTER #ifdef's to be removed from the MD interrupt
code.
- Rename the intr_event 'eoi', 'disable', and 'enable' hooks to
'post_filter', 'pre_ithread', and 'post_ithread' to be less x86-centric.
Also, add a comment describe what the MI code expects them to do.
- On amd64, i386, and powerpc this is effectively a NOP.
- On arm, don't bother masking the interrupt unless the ithread is
scheduled in the non-INTR_FILTER case to match what INTR_FILTER did.
Also, don't bother unmasking the interrupt in the post_filter case if
we never masked it. The INTR_FILTER case had been doing this by having
arm_unmask_irq for the post_filter (formerly 'eoi') hook.
- On ia64, stray interrupts are now masked for the non-INTR_FILTER case.
They were already masked in the INTR_FILTER case.
- On sparc64, use the a NULL pre_ithread hook and use intr_enable_eoi() for
both the 'post_filter' and 'post_ithread' hooks to match what the
non-INTR_FILTER code did.
- On sun4v, retire the ithread wrapper hack by using an appropriate
'post_ithread' hook instead (it's what 'post_ithread'/'enable' was
designed to do even in 5.x).

Glanced at by: piso
Reviewed by: marius
Requested by: marius [1], [5]
Tested on: amd64, i386, arm, sparc64

Simplify the interrupt code a bit:
- Always include the ie_disable and ie_eoi methods in 'struct intr_event'
and collapse down to one intr_event_create() routine. The disable and
eoi hooks simply aren't used currently in the !INTR_FILTER case.
- Expand 'disab' to 'disable' in a few places.
- Use function casts for arm and i386:intr_eoi_src() instead of wrapper
routines since to trim one extra indirection.

Compiled on: {arm,amd64,i386,ia64,ppc,sparc64} x {FILTER, !FILTER}
Tested on: {amd64,i386} x {FILTER, !FILTER}

Add preliminary support for binding interrupts to CPUs:
- Add a new intr_event method ie_assign_cpu() that is invoked when the MI
code wishes to bind an interrupt source to an individual CPU. The MD
code may reject the binding with an error. If an assign_cpu function
is not provided, then the kernel assumes the platform does not support
binding interrupts to CPUs and fails all requests to do so.
- Bind ithreads to CPUs on their next execution loop once an interrupt
event is bound to a CPU. Only shared ithreads are bound. We currently
leave private ithreads for drivers using filters + ithreads in the
INTR_FILTER case unbound.
- A new intr_event_bind() routine is used to bind an interrupt event to
a CPU.
- Implement binding on amd64 and i386 by way of the existing pic_assign_cpu
PIC method.
- For x86, provide a 'intr_bind(IRQ, cpu)' wrapper routine that looks up
an interrupt source and binds its interrupt event to the specified CPU.
MI code can currently (ab)use this by doing:

intr_bind(rman_get_start(irq_res), cpu);

however, I plan to add a truly MI interface (probably a bus_bind_intr(9))
where the implementation in the x86 nexus(4) driver would end up calling
intr_bind() internally.

Requested by: kmacy, gallatin, jeff
Tested on: {amd64, i386} x {regular, INTR_FILTER}

Bring in the reminaing bits to make interrupt filtering work:

o push much of the i386 and amd64 MD interrupt handling code
(intr_machdep.c::intr_execute_handlers()) into MI code
(kern_intr.c::ithread_loop())
o move filter handling to kern_intr.c::intr_filter_loop()
o factor out the code necessary to mask and ack an interrupt event
(intr_machdep.c::intr_eoi_src() and intr_machdep.c::intr_disab_eoi_src()),
and make them part of 'struct intr_event', passing them as arguments to
kern_intr.c::intr_event_create().
o spawn a private ithread per handler (struct intr_handler::ih_thread)
with filter and ithread functions.

Approved by: re (implicit?)

Bump the interrupt storm detection counter to 1000. My slow fileserver
gets a bogus irq storm detected when periodic daily kicks off at 3 am
and disconnects the disk. Change the print logic to print once per second
when the storm is occurring instead of only once. Otherwise, it appeared
that something else was causing the errors each night at 3 am since the
print only occurred the first time.

Reviewed by: jhb
MFC after: 1 week

o break newbus api: add a new argument of type driver_filter_t to
bus_setup_intr()

o add an int return code to all fast handlers

o retire INTR_FAST/IH_FAST

For more info: http://docs.freebsd.org/cgi/getmsg.cgi?fetch=465712+0+current/freebsd-current

Reviewed by: many
Approved by: re@

Add a function to return the MD interrupt source cookie associated with
an interrupt event. Use this in the x86 code to fixup the intrcnt names
when an interrupt handler is removed.

Add a swi_remove() function to teardown software interrupt handlers. For
now it just calls intr_event_remove_handler(), but at some point it might
also be responsible for tearing down interrupt events created via swi_add.

Reorganize the interrupt handling code a bit to make a few things cleaner
and increase flexibility to allow various different approaches to be tried
in the future.
- Split struct ithd up into two pieces. struct intr_event holds the list
of interrupt handlers associated with interrupt sources.
struct intr_thread contains the data relative to an interrupt thread.
Currently we still provide a 1:1 relationship of events to threads
with the exception that events only have an associated thread if there
is at least one threaded interrupt handler attached to the event. This
means that on x86 we no longer have 4 bazillion interrupt threads with
no handlers. It also means that interrupt events with only INTR_FAST
handlers no longer have an associated thread either.
- Renamed struct intrhand to struct intr_handler to follow the struct
intr_foo naming convention. This did require renaming the powerpc
MD struct intr_handler to struct ppc_intr_handler.
- INTR_FAST no longer implies INTR_EXCL on all architectures except for
powerpc. This means that multiple INTR_FAST handlers can attach to the
same interrupt and that INTR_FAST and non-INTR_FAST handlers can attach
to the same interrupt. Sharing INTR_FAST handlers may not always be
desirable, but having sio(4) and uhci(4) fight over an IRQ isn't fun
either. Drivers can always still use INTR_EXCL to ask for an interrupt
exclusively. The way this sharing works is that when an interrupt
comes in, all the INTR_FAST handlers are executed first, and if any
threaded handlers exist, the interrupt thread is scheduled afterwards.
This type of layout also makes it possible to investigate using interrupt
filters ala OS X where the filter determines whether or not its companion
threaded handler should run.
- Aside from the INTR_FAST changes above, the impact on MD interrupt code
is mostly just 's/ithread/intr_event/'.
- A new MI ddb command 'show intrs' walks the list of interrupt events
dumping their state. It also has a '/v' verbose switch which dumps
info about all of the handlers attached to each event.
- We currently don't destroy an interrupt thread when the last threaded
handler is removed because it would suck for things like ppbus(8)'s
braindead behavior. The code is present, though, it is just under
#if 0 for now.
- Move the code to actually execute the threaded handlers for an interrrupt
event into a separate function so that ithread_loop() becomes more
readable. Previously this code was all in the middle of ithread_loop()
and indented halfway across the screen.
- Made struct intr_thread private to kern_intr.c and replaced td_ithd
with a thread private flag TDP_ITHREAD.
- In statclock, check curthread against idlethread directly rather than
curthread's proc against idlethread's proc. (Not really related to intr
changes)

Tested on: alpha, amd64, i386, sparc64
Tested on: arm, ia64 (older version of patch by cognet and marcel)

Remove public declarations of variables that were forgotten when they were
made static.

/* -> /*- for license, minor formatting changes

Remove SWI_CAMNET since it's no longer used. Re-sort SWI priorities in its
absence.

Implement preemption of kernel threads natively in the scheduler rather
than as one-off hacks in various other parts of the kernel:
- Add a function maybe_preempt() that is called from sched_add() to
determine if a thread about to be added to a run queue should be
preempted to directly. If it is not safe to preempt or if the new
thread does not have a high enough priority, then the function returns
false and sched_add() adds the thread to the run queue. If the thread
should be preempted to but the current thread is in a nested critical
section, then the flag TDF_OWEPREEMPT is set and the thread is added
to the run queue. Otherwise, mi_switch() is called immediately and the
thread is never added to the run queue since it is switch to directly.
When exiting an outermost critical section, if TDF_OWEPREEMPT is set,
then clear it and call mi_switch() to perform the deferred preemption.
- Remove explicit preemption from ithread_schedule() as calling
setrunqueue() now does all the correct work. This also removes the
do_switch argument from ithread_schedule().
- Do not use the manual preemption code in mtx_unlock if the architecture
supports native preemption.
- Don't call mi_switch() in a loop during shutdown to give ithreads a
chance to run if the architecture supports native preemption since
the ithreads will just preempt DELAY().
- Don't call mi_switch() from the page zeroing idle thread for
architectures that support native preemption as it is unnecessary.
- Native preemption is enabled on the same archs that supported ithread
preemption, namely alpha, i386, and amd64.

This change should largely be a NOP for the default case as committed
except that we will do fewer context switches in a few cases and will
avoid the run queues completely when preempting.

Approved by: scottl (with his re@ hat)

Adjust the priorities of software interrupts. Bump SWI_CLOCK up to 5
and bump all of the taskqueue swi's to 6. This gives callouts higher
priority than taskqueue tasks and gives all taskqueue tasks the same
priority.

Discussed with: bde

Expand the argument to the ithread enable/disable helper hooks from an
int to something big enough to hold a pointer. amd64 needs this.

- Add a DDB command 'show intrcnt' to show the non-zero interrupt counts.
- Add a DDB function to dump the contents of an ithread and optionally
details about each handler in that ithread. This function can be used
by MD code to implement DDB commands that display information about
interrupt sources and their registered handlers.

"fast swi" taskqueue support. This is a taskqueue that uses spinlocks
making it useful for dispatching swi tasks from fast interrupt handlers.

Sponsered by: FreeBSD Foundation

Introduce a new taskqueue that runs completely free of Giant, and in
turns runs its tasks free of Giant too. It is intended that as drivers
become locked down, they will move out of the old, Giant-bound taskqueue
and into this new one. The old taskqueue has been renamed to
taskqueue_swi_giant, and the new one keeps the name taskqueue_swi.

Remove __P

Change the preemption code for software interrupt thread schedules and
mutex releases to not require flags for the cases when preemption is
not allowed:

The purpose of the MTX_NOSWITCH and SWI_NOSWITCH flags is to prevent
switching to a higher priority thread on mutex releease and swi schedule,
respectively when that switch is not safe. Now that the critical section
API maintains a per-thread nesting count, the kernel can easily check
whether or not it should switch without relying on flags from the
programmer. This fixes a few bugs in that all current callers of
swi_sched() used SWI_NOSWITCH, when in fact, only the ones called from
fast interrupt handlers and the swi_sched of softclock needed this flag.
Note that to ensure that swi_sched()'s in clock and fast interrupt
handlers do not switch, these handlers have to be explicitly wrapped
in critical_enter/exit pairs. Presently, just wrapping the handlers is
sufficient, but in the future with the fully preemptive kernel, the
interrupt must be EOI'd before critical_exit() is called. (critical_exit()
can switch due to a deferred preemption in a fully preemptive kernel.)

I've tested the changes to the interrupt code on i386 and alpha. I have
not tested ia64, but the interrupt code is almost identical to the alpha
code, so I expect it will work fine. PowerPC and ARM do not yet have
interrupt code in the tree so they shouldn't be broken. Sparc64 is
broken, but that's been ok'd by jake and tmm who will be fixing the
interrupt code for sparc64 shortly.

Reviewed by: peter
Tested on: i386, alpha

KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after: ha ha ha ha

style(9) the structure definitions.

Clean up the code exporting interrupt statistics via sysctl a bit:
- move the sysctl code to kern_intr.c
- do not use INTRCNT_COUNT, but rather eintrcnt - intrcnt to determine
the length of the intrcnt array
- move the declarations of intrnames, eintrnames, intrcnt and eintrcnt
from machine-dependent include files to sys/interrupt.h
- remove the hw.nintr sysctl, it is not needed.
- fix various style bugs

Requested by: bde
Reviewed by: bde (some time ago)

- Remove the global ithread_list_lock spin lock in favor of per-ithread
sleep locks.
- Delay returning from ithread_remove_handler() until we are certain that
the interrupt handler being removed has in fact been removed from the
ithread.
- XXX: There is still a problem in that nothing protects the kernel from
adding a new handler while the ithread is running, though with our
current architectures this is not a problem.

Requested by: gibbs (2)

Initiate the deorbit burn sequence for sys/ipl.h by moving the software
interrupt priorities over to sys/interrupt.h next to the software interrupt
API.

Work around a race condition where an interrupt handler can be removed from
an interrupt thread while the interrupt thread is blocked on Giant waiting
to execute the interrupt handler being removed. The result was that the
intrhand structure would be free'd, and we would call 0xdeadc0de. The work
around is to check to see if the interrupt thread is idle when removing a
handler. If not, then we mark the interrupt handler as being dead using
the new IH_DEAD flag and don't remove it from the interrupt threads' list
of handlers. When the interrupt thread resumes, it will see a dead handler
while traversing the list of handlers and will remove the handler then.

- Add a new ithread_schedule() function to do the bulk of the work of
scheduling an interrupt thread to run when needed. This has the side
effect of enabling support for entropy gathering from interrupts on
all architectures.
- Change the software interrupt and x86 and alpha hardware interrupt code
to use ithread_schedule() for most of their processing when scheduling
an interrupt to run.
- Remove the pesky Warning message about interrupt threads having entropy
enabled. I'm not sure why I put that in there in the first place.
- Add more error checking for parameters and change some cases that
returned EINVAL to panic on failure instead via KASSERT().
- Instead of doing a documented evil hack of setting the P_NOLOAD flag
on every interrupt thread whose pri was SWI_CLOCK, set the flag
explicity for clk_ithd's proc during start_softintr().

- Move struct ithd to sys/interrupt.h.
- Add a set of MI helper functions for interrupt threads:
- ithread_create() creates a new interrupt thread
- ithread_destroy() destroys an interrupt thread
- ithread_add_handler() attaches a new handler to an interrupt thread
- ithread_remove_handler() detaches a handler from an interrupt thread
- Rename sinthand_add() and sched_swi() to swi_add() and swi_sched()
respectively so that they live in a consistent namespace.
- struct intrhand is no longer a public type. It would be private to
kern_intr.c but the current implementation of fast interrupts on the
alpha requires the type to be exported. However, all handlers should
be treated as void * cookies in the way that new-bus treats them. This
includes references to software interrupt handlers.

- Overhaul the software interrupt code to use interrupt threads for each
type of software interrupt. Roughly, what used to be a bit in spending
now maps to a swi thread. Each thread can have multiple handlers, just
like a hardware interrupt thread.
- Instead of using a bitmask of pending interrupts, we schedule the specific
software interrupt thread to run, so spending, NSWI, and the shandlers
array are no longer needed. We can now have an arbitrary number of
software interrupt threads. When you register a software interrupt
thread via sinthand_add(), you get back a struct intrhand that you pass
to sched_swi() when you wish to schedule your swi thread to run.
- Convert the name of 'struct intrec' to 'struct intrhand' as it is a bit
more intuitive. Also, prefix all the members of struct intrhand with
'ih_'.
- Make swi_net() a MI function since there is now no point in it being
MD.

Submitted by: cp

- Heavyweight interrupt threads on the alpha for device I/O interrupts.
- Make softinterrupts (SWI's) almost completely MI, and divorce them
completely from the x86 hardware interrupt code.
- The ihandlers array is now gone. Instead, there is a MI shandlers array
that just contains SWI handlers.
- Most of the former machine/ipl.h files have moved to a new sys/ipl.h.
- Stub out all the spl*() functions on all architectures.

Submitted by: dfr

- Remove the inthand2_t type and use the equivalent driver_intr_t type from
newbus for referencing device interrupt handlers.
- Move the 'struct intrec' type which describes interrupt sources into
sys/interrupt.h instead of making it just be a x86 structure.
- Don't create 'ithd' and 'intrec' typedefs, instead, just use 'struct ithd'
and 'struct intrec'
- Move the code to translate new-bus interrupt flags into an interrupt thread
priority out of the x86 nexus code and into a MI ithread_priority()
function in sys/kern/kern_intr.c.
- Remove now-uneeded x86-specific headers from sys/dev/ata/ata-all.c and
sys/pci/pci_compat.c.

$Id$ -> $FreeBSD$

Stage 1 of a cleanup of the i386 interrupt registration mechanism.
Interrupts under the new scheme are managed by the i386 nexus with the
awareness of the resource manager. There is further room for optimizing
the interfaces still. All the users of register_intr()/intr_create()
should be gone, with the exception of pcic and i386/isa/clock.c.

Implemented dynamic registration of software interrupt handlers. Not
used yet.

Use dummy SWI handlers to avoid some checks for null pointers.

Back out 'conflicts' with IRQs, remove intr_registered() decl

Add safety check in case "conflicts" keyword specified more times than
needed

The defines INTR_FAST and INTR_EXCL are part of the public interface. The
previous commit made them private which broke things.

Move "typedef struct intrec {} intrec" from sys/interrupt.h to kern_intr.c
since that's the only place that it's used.

Submitted by: se (apparently on suggestion from dfr)

s/intrmask/intrmask_t/g
remove warning about ICU_LEN > 32, it's not likely to happen like this,
and besides, ICU_LEN is not the ideal indicator of "number of interrupts".

Reviewed by: bde, se

Add support for shared interrupts to the kernel. This code is meant
be (eventually) architecture independent. It provides an emulation
of the ISA interrupt registration function register_intr(), but that
function does no longer manipulated the interrupt controller and
interrupt descriptor table, but calls the architecture dependent
function setup_icu() for that purpose.

After theISA/EISA bus code has been modified to directly call the new
interrupt registartion functions (intr_create() and intr_connect()),
the emulation of register_intr() should be dropped.

The C level interrupt handler function should take a (void*) argument,
and the function pointer type (inthand2_t) should defined in some other
place than isa_device.h.

This commit is a pre-requisite for the removal of the PCI specific shared
interrupt code.

Reviewed by: dfr,bde