2 * Copyright (c) 2003 Matthew Dillon <dillon@backplane.com> All rights reserved.
3 * Copyright (c) 1997, Stefan Esser <se@freebsd.org> All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 * $FreeBSD: src/sys/kern/kern_intr.c,v 1.24.2.1 2001/10/14 20:05:50 luigi Exp $
27 * $DragonFly: src/sys/kern/kern_intr.c,v 1.55 2008/09/01 12:49:00 sephe Exp $
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/malloc.h>
34 #include <sys/kernel.h>
35 #include <sys/sysctl.h>
36 #include <sys/thread.h>
38 #include <sys/random.h>
39 #include <sys/serialize.h>
40 #include <sys/interrupt.h>
42 #include <sys/machintr.h>
44 #include <machine/frame.h>
46 #include <sys/interrupt.h>
48 #include <sys/thread2.h>
49 #include <sys/mplock2.h>
53 typedef struct intrec
{
55 struct intr_info
*info
;
61 struct lwkt_serialize
*serializer
;
66 struct thread i_thread
;
67 struct random_softc i_random
;
69 long i_count
; /* interrupts dispatched */
70 int i_mplock_required
;
75 unsigned long i_straycount
;
76 } intr_info_ary
[MAX_INTS
];
78 int max_installed_hard_intr
;
79 int max_installed_soft_intr
;
81 #define EMERGENCY_INTR_POLLING_FREQ_MAX 20000
83 static int sysctl_emergency_freq(SYSCTL_HANDLER_ARGS
);
84 static int sysctl_emergency_enable(SYSCTL_HANDLER_ARGS
);
85 static void emergency_intr_timer_callback(systimer_t
, struct intrframe
*);
86 static void ithread_handler(void *arg
);
87 static void ithread_emergency(void *arg
);
88 static void report_stray_interrupt(int intr
, struct intr_info
*info
);
89 static void int_moveto_destcpu(int *, int *, int);
90 static void int_moveto_origcpu(int, int);
92 static void intr_get_mplock(void);
95 int intr_info_size
= sizeof(intr_info_ary
) / sizeof(intr_info_ary
[0]);
97 static struct systimer emergency_intr_timer
;
98 static struct thread emergency_intr_thread
;
100 #define ISTATE_NOTHREAD 0
101 #define ISTATE_NORMAL 1
102 #define ISTATE_LIVELOCKED 2
105 static int intr_mpsafe
= 1;
106 static int intr_migrate
= 0;
107 static int intr_migrate_count
;
108 TUNABLE_INT("kern.intr_mpsafe", &intr_mpsafe
);
109 SYSCTL_INT(_kern
, OID_AUTO
, intr_mpsafe
,
110 CTLFLAG_RW
, &intr_mpsafe
, 0, "Run INTR_MPSAFE handlers without the BGL");
111 SYSCTL_INT(_kern
, OID_AUTO
, intr_migrate
,
112 CTLFLAG_RW
, &intr_migrate
, 0, "Migrate to cpu holding BGL");
113 SYSCTL_INT(_kern
, OID_AUTO
, intr_migrate_count
,
114 CTLFLAG_RW
, &intr_migrate_count
, 0, "");
116 static int livelock_limit
= 40000;
117 static int livelock_lowater
= 20000;
118 static int livelock_debug
= -1;
119 SYSCTL_INT(_kern
, OID_AUTO
, livelock_limit
,
120 CTLFLAG_RW
, &livelock_limit
, 0, "Livelock interrupt rate limit");
121 SYSCTL_INT(_kern
, OID_AUTO
, livelock_lowater
,
122 CTLFLAG_RW
, &livelock_lowater
, 0, "Livelock low-water mark restore");
123 SYSCTL_INT(_kern
, OID_AUTO
, livelock_debug
,
124 CTLFLAG_RW
, &livelock_debug
, 0, "Livelock debug intr#");
126 static int emergency_intr_enable
= 0; /* emergency interrupt polling */
127 TUNABLE_INT("kern.emergency_intr_enable", &emergency_intr_enable
);
128 SYSCTL_PROC(_kern
, OID_AUTO
, emergency_intr_enable
, CTLTYPE_INT
| CTLFLAG_RW
,
129 0, 0, sysctl_emergency_enable
, "I", "Emergency Interrupt Poll Enable");
131 static int emergency_intr_freq
= 10; /* emergency polling frequency */
132 TUNABLE_INT("kern.emergency_intr_freq", &emergency_intr_freq
);
133 SYSCTL_PROC(_kern
, OID_AUTO
, emergency_intr_freq
, CTLTYPE_INT
| CTLFLAG_RW
,
134 0, 0, sysctl_emergency_freq
, "I", "Emergency Interrupt Poll Frequency");
137 * Sysctl support routines
140 sysctl_emergency_enable(SYSCTL_HANDLER_ARGS
)
144 enabled
= emergency_intr_enable
;
145 error
= sysctl_handle_int(oidp
, &enabled
, 0, req
);
146 if (error
|| req
->newptr
== NULL
)
148 emergency_intr_enable
= enabled
;
149 if (emergency_intr_enable
) {
150 systimer_adjust_periodic(&emergency_intr_timer
,
151 emergency_intr_freq
);
153 systimer_adjust_periodic(&emergency_intr_timer
, 1);
159 sysctl_emergency_freq(SYSCTL_HANDLER_ARGS
)
163 phz
= emergency_intr_freq
;
164 error
= sysctl_handle_int(oidp
, &phz
, 0, req
);
165 if (error
|| req
->newptr
== NULL
)
169 else if (phz
> EMERGENCY_INTR_POLLING_FREQ_MAX
)
170 phz
= EMERGENCY_INTR_POLLING_FREQ_MAX
;
172 emergency_intr_freq
= phz
;
173 if (emergency_intr_enable
) {
174 systimer_adjust_periodic(&emergency_intr_timer
,
175 emergency_intr_freq
);
177 systimer_adjust_periodic(&emergency_intr_timer
, 1);
183 * Register an SWI or INTerrupt handler.
186 register_swi(int intr
, inthand2_t
*handler
, void *arg
, const char *name
,
187 struct lwkt_serialize
*serializer
)
189 if (intr
< FIRST_SOFTINT
|| intr
>= MAX_INTS
)
190 panic("register_swi: bad intr %d", intr
);
191 return(register_int(intr
, handler
, arg
, name
, serializer
, 0));
195 register_swi_mp(int intr
, inthand2_t
*handler
, void *arg
, const char *name
,
196 struct lwkt_serialize
*serializer
)
198 if (intr
< FIRST_SOFTINT
|| intr
>= MAX_INTS
)
199 panic("register_swi: bad intr %d", intr
);
200 return(register_int(intr
, handler
, arg
, name
, serializer
, INTR_MPSAFE
));
204 register_int(int intr
, inthand2_t
*handler
, void *arg
, const char *name
,
205 struct lwkt_serialize
*serializer
, int intr_flags
)
207 struct intr_info
*info
;
208 struct intrec
**list
;
210 int orig_cpuid
, cpuid
;
212 if (intr
< 0 || intr
>= MAX_INTS
)
213 panic("register_int: bad intr %d", intr
);
216 info
= &intr_info_ary
[intr
];
219 * Construct an interrupt handler record
221 rec
= kmalloc(sizeof(struct intrec
), M_DEVBUF
, M_INTWAIT
);
222 rec
->name
= kmalloc(strlen(name
) + 1, M_DEVBUF
, M_INTWAIT
);
223 strcpy(rec
->name
, name
);
226 rec
->handler
= handler
;
229 rec
->intr_flags
= intr_flags
;
231 rec
->serializer
= serializer
;
234 * Create an emergency polling thread and set up a systimer to wake
237 if (emergency_intr_thread
.td_kstack
== NULL
) {
238 lwkt_create(ithread_emergency
, NULL
, NULL
,
239 &emergency_intr_thread
, TDF_STOPREQ
|TDF_INTTHREAD
, -1,
241 systimer_init_periodic_nq(&emergency_intr_timer
,
242 emergency_intr_timer_callback
, &emergency_intr_thread
,
243 (emergency_intr_enable
? emergency_intr_freq
: 1));
246 int_moveto_destcpu(&orig_cpuid
, &cpuid
, intr
);
249 * Create an interrupt thread if necessary, leave it in an unscheduled
252 if (info
->i_state
== ISTATE_NOTHREAD
) {
253 info
->i_state
= ISTATE_NORMAL
;
254 lwkt_create((void *)ithread_handler
, (void *)(intptr_t)intr
, NULL
,
255 &info
->i_thread
, TDF_STOPREQ
|TDF_INTTHREAD
|TDF_MPSAFE
, -1,
257 if (intr
>= FIRST_SOFTINT
)
258 lwkt_setpri(&info
->i_thread
, TDPRI_SOFT_NORM
);
260 lwkt_setpri(&info
->i_thread
, TDPRI_INT_MED
);
261 info
->i_thread
.td_preemptable
= lwkt_preempt
;
264 list
= &info
->i_reclist
;
267 * Keep track of how many fast and slow interrupts we have.
268 * Set i_mplock_required if any handler in the chain requires
269 * the MP lock to operate.
271 if ((intr_flags
& INTR_MPSAFE
) == 0)
272 info
->i_mplock_required
= 1;
273 if (intr_flags
& INTR_FAST
)
279 * Enable random number generation keying off of this interrupt.
281 if ((intr_flags
& INTR_NOENTROPY
) == 0 && info
->i_random
.sc_enabled
== 0) {
282 info
->i_random
.sc_enabled
= 1;
283 info
->i_random
.sc_intr
= intr
;
287 * Add the record to the interrupt list.
290 while (*list
!= NULL
)
291 list
= &(*list
)->next
;
296 * Update max_installed_hard_intr to make the emergency intr poll
297 * a bit more efficient.
299 if (intr
< FIRST_SOFTINT
) {
300 if (max_installed_hard_intr
<= intr
)
301 max_installed_hard_intr
= intr
+ 1;
303 if (max_installed_soft_intr
<= intr
)
304 max_installed_soft_intr
= intr
+ 1;
308 * Setup the machine level interrupt vector
310 * XXX temporary workaround for some ACPI brokedness. ACPI installs
311 * its interrupt too early, before the IOAPICs have been configured,
312 * which means the IOAPIC is not enabled by the registration of the
313 * ACPI interrupt. Anything else sharing that IRQ will wind up not
314 * being enabled. Temporarily work around the problem by always
315 * installing and enabling on every new interrupt handler, even
316 * if one has already been setup on that irq.
318 if (intr
< FIRST_SOFTINT
/* && info->i_slow + info->i_fast == 1*/) {
319 if (machintr_vector_setup(intr
, intr_flags
))
320 kprintf("machintr_vector_setup: failed on irq %d\n", intr
);
323 int_moveto_origcpu(orig_cpuid
, cpuid
);
329 unregister_swi(void *id
)
335 unregister_int(void *id
)
337 struct intr_info
*info
;
338 struct intrec
**list
;
340 int intr
, orig_cpuid
, cpuid
;
342 intr
= ((intrec_t
)id
)->intr
;
344 if (intr
< 0 || intr
>= MAX_INTS
)
345 panic("register_int: bad intr %d", intr
);
347 info
= &intr_info_ary
[intr
];
349 int_moveto_destcpu(&orig_cpuid
, &cpuid
, intr
);
352 * Remove the interrupt descriptor, adjust the descriptor count,
353 * and teardown the machine level vector if this was the last interrupt.
356 list
= &info
->i_reclist
;
357 while ((rec
= *list
) != NULL
) {
366 if (rec
->intr_flags
& INTR_FAST
)
370 if (intr
< FIRST_SOFTINT
&& info
->i_fast
+ info
->i_slow
== 0)
371 machintr_vector_teardown(intr
);
374 * Clear i_mplock_required if no handlers in the chain require the
377 for (rec0
= info
->i_reclist
; rec0
; rec0
= rec0
->next
) {
378 if ((rec0
->intr_flags
& INTR_MPSAFE
) == 0)
382 info
->i_mplock_required
= 0;
387 int_moveto_origcpu(orig_cpuid
, cpuid
);
393 kfree(rec
->name
, M_DEVBUF
);
394 kfree(rec
, M_DEVBUF
);
396 kprintf("warning: unregister_int: int %d handler for %s not found\n",
397 intr
, ((intrec_t
)id
)->name
);
402 get_registered_name(int intr
)
406 if (intr
< 0 || intr
>= MAX_INTS
)
407 panic("register_int: bad intr %d", intr
);
409 if ((rec
= intr_info_ary
[intr
].i_reclist
) == NULL
)
418 count_registered_ints(int intr
)
420 struct intr_info
*info
;
422 if (intr
< 0 || intr
>= MAX_INTS
)
423 panic("register_int: bad intr %d", intr
);
424 info
= &intr_info_ary
[intr
];
425 return(info
->i_fast
+ info
->i_slow
);
429 get_interrupt_counter(int intr
)
431 struct intr_info
*info
;
433 if (intr
< 0 || intr
>= MAX_INTS
)
434 panic("register_int: bad intr %d", intr
);
435 info
= &intr_info_ary
[intr
];
436 return(info
->i_count
);
441 swi_setpriority(int intr
, int pri
)
443 struct intr_info
*info
;
445 if (intr
< FIRST_SOFTINT
|| intr
>= MAX_INTS
)
446 panic("register_swi: bad intr %d", intr
);
447 info
= &intr_info_ary
[intr
];
448 if (info
->i_state
!= ISTATE_NOTHREAD
)
449 lwkt_setpri(&info
->i_thread
, pri
);
453 register_randintr(int intr
)
455 struct intr_info
*info
;
457 if (intr
< 0 || intr
>= MAX_INTS
)
458 panic("register_randintr: bad intr %d", intr
);
459 info
= &intr_info_ary
[intr
];
460 info
->i_random
.sc_intr
= intr
;
461 info
->i_random
.sc_enabled
= 1;
465 unregister_randintr(int intr
)
467 struct intr_info
*info
;
469 if (intr
< 0 || intr
>= MAX_INTS
)
470 panic("register_swi: bad intr %d", intr
);
471 info
= &intr_info_ary
[intr
];
472 info
->i_random
.sc_enabled
= -1;
476 next_registered_randintr(int intr
)
478 struct intr_info
*info
;
480 if (intr
< 0 || intr
>= MAX_INTS
)
481 panic("register_swi: bad intr %d", intr
);
482 while (intr
< MAX_INTS
) {
483 info
= &intr_info_ary
[intr
];
484 if (info
->i_random
.sc_enabled
> 0)
492 * Dispatch an interrupt. If there's nothing to do we have a stray
493 * interrupt and can just return, leaving the interrupt masked.
495 * We need to schedule the interrupt and set its i_running bit. If
496 * we are not on the interrupt thread's cpu we have to send a message
497 * to the correct cpu that will issue the desired action (interlocking
498 * with the interrupt thread's critical section). We do NOT attempt to
499 * reschedule interrupts whos i_running bit is already set because
500 * this would prematurely wakeup a livelock-limited interrupt thread.
502 * i_running is only tested/set on the same cpu as the interrupt thread.
504 * We are NOT in a critical section, which will allow the scheduled
505 * interrupt to preempt us. The MP lock might *NOT* be held here.
510 sched_ithd_remote(void *arg
)
512 sched_ithd((int)(intptr_t)arg
);
520 struct intr_info
*info
;
522 info
= &intr_info_ary
[intr
];
525 if (info
->i_state
!= ISTATE_NOTHREAD
) {
526 if (info
->i_reclist
== NULL
) {
527 report_stray_interrupt(intr
, info
);
530 if (info
->i_thread
.td_gd
== mycpu
) {
531 if (info
->i_running
== 0) {
533 if (info
->i_state
!= ISTATE_LIVELOCKED
)
534 lwkt_schedule(&info
->i_thread
); /* MIGHT PREEMPT */
537 lwkt_send_ipiq(info
->i_thread
.td_gd
,
538 sched_ithd_remote
, (void *)(intptr_t)intr
);
541 if (info
->i_running
== 0) {
543 if (info
->i_state
!= ISTATE_LIVELOCKED
)
544 lwkt_schedule(&info
->i_thread
); /* MIGHT PREEMPT */
549 report_stray_interrupt(intr
, info
);
554 report_stray_interrupt(int intr
, struct intr_info
*info
)
556 ++info
->i_straycount
;
557 if (info
->i_straycount
< 10) {
558 if (info
->i_errorticks
== ticks
)
560 info
->i_errorticks
= ticks
;
561 kprintf("sched_ithd: stray interrupt %d on cpu %d\n",
563 } else if (info
->i_straycount
== 10) {
564 kprintf("sched_ithd: %ld stray interrupts %d on cpu %d - "
565 "there will be no further reports\n",
566 info
->i_straycount
, intr
, mycpuid
);
571 * This is run from a periodic SYSTIMER (and thus must be MP safe, the BGL
572 * might not be held).
575 ithread_livelock_wakeup(systimer_t st
)
577 struct intr_info
*info
;
579 info
= &intr_info_ary
[(int)(intptr_t)st
->data
];
580 if (info
->i_state
!= ISTATE_NOTHREAD
)
581 lwkt_schedule(&info
->i_thread
);
585 * Schedule ithread within fast intr handler
587 * XXX Protect sched_ithd() call with gd_intr_nesting_level?
588 * Interrupts aren't enabled, but still...
591 ithread_fast_sched(int intr
, thread_t td
)
596 * We are already in critical section, exit it now to
601 crit_enter_quick(td
);
607 * This function is called directly from the ICU or APIC vector code assembly
608 * to process an interrupt. The critical section and interrupt deferral
609 * checks have already been done but the function is entered WITHOUT
610 * a critical section held. The BGL may or may not be held.
612 * Must return non-zero if we do not want the vector code to re-enable
613 * the interrupt (which we don't if we have to schedule the interrupt)
615 int ithread_fast_handler(struct intrframe
*frame
);
618 ithread_fast_handler(struct intrframe
*frame
)
621 struct intr_info
*info
;
622 struct intrec
**list
;
627 intrec_t rec
, next_rec
;
631 intr
= frame
->if_vec
;
635 /* We must be in critical section. */
636 KKASSERT(td
->td_pri
>= TDPRI_CRIT
);
638 info
= &intr_info_ary
[intr
];
641 * If we are not processing any FAST interrupts, just schedule the thing.
643 if (info
->i_fast
== 0) {
645 ithread_fast_sched(intr
, td
);
650 * This should not normally occur since interrupts ought to be
651 * masked if the ithread has been scheduled or is running.
657 * Bump the interrupt nesting level to process any FAST interrupts.
658 * Obtain the MP lock as necessary. If the MP lock cannot be obtained,
659 * schedule the interrupt thread to deal with the issue instead.
661 * To reduce overhead, just leave the MP lock held once it has been
664 ++gd
->gd_intr_nesting_level
;
666 must_schedule
= info
->i_slow
;
671 list
= &info
->i_reclist
;
672 for (rec
= *list
; rec
; rec
= next_rec
) {
673 next_rec
= rec
->next
; /* rec may be invalid after call */
675 if (rec
->intr_flags
& INTR_FAST
) {
677 if ((rec
->intr_flags
& INTR_MPSAFE
) == 0 && got_mplock
== 0) {
678 if (try_mplock() == 0) {
679 /* Couldn't get the MP lock; just schedule it. */
686 if (rec
->serializer
) {
687 must_schedule
+= lwkt_serialize_handler_try(
688 rec
->serializer
, rec
->handler
,
689 rec
->argument
, frame
);
691 rec
->handler(rec
->argument
, frame
);
699 --gd
->gd_intr_nesting_level
;
706 * If we had a problem, or mixed fast and slow interrupt handlers are
707 * registered, schedule the ithread to catch the missed records (it
708 * will just re-run all of them). A return value of 0 indicates that
709 * all handlers have been run and the interrupt can be re-enabled, and
710 * a non-zero return indicates that the interrupt thread controls
713 if (must_schedule
> 0)
714 ithread_fast_sched(intr
, td
);
715 else if (must_schedule
== 0)
717 return(must_schedule
);
721 * Interrupt threads run this as their main loop.
723 * The handler begins execution outside a critical section and with the BGL
726 * The i_running state starts at 0. When an interrupt occurs, the hardware
727 * interrupt is disabled and sched_ithd() The HW interrupt remains disabled
728 * until all routines have run. We then call ithread_done() to reenable
729 * the HW interrupt and deschedule us until the next interrupt.
731 * We are responsible for atomically checking i_running and ithread_done()
732 * is responsible for atomically checking for platform-specific delayed
733 * interrupts. i_running for our irq is only set in the context of our cpu,
734 * so a critical section is a sufficient interlock.
736 #define LIVELOCK_TIMEFRAME(freq) ((freq) >> 2) /* 1/4 second */
739 ithread_handler(void *arg
)
741 struct intr_info
*info
;
746 struct intrec
**list
;
749 struct systimer ill_timer
; /* enforced freq. timer */
750 u_int ill_count
; /* interrupt livelock counter */
753 intr
= (int)(intptr_t)arg
;
754 info
= &intr_info_ary
[intr
];
755 list
= &info
->i_reclist
;
758 * The loop must be entered with one critical section held. The thread
759 * is created with TDF_MPSAFE so the MP lock is not held on start.
762 lseconds
= gd
->gd_time_seconds
;
768 * The chain is only considered MPSAFE if all its interrupt handlers
769 * are MPSAFE. However, if intr_mpsafe has been turned off we
770 * always operate with the BGL.
773 if (intr_mpsafe
== 0) {
778 } else if (info
->i_mplock_required
!= mpheld
) {
779 if (info
->i_mplock_required
) {
780 KKASSERT(mpheld
== 0);
784 KKASSERT(mpheld
!= 0);
791 * scheduled cpu may have changed, see intr_get_mplock()
797 * If an interrupt is pending, clear i_running and execute the
798 * handlers. Note that certain types of interrupts can re-trigger
799 * and set i_running again.
801 * Each handler is run in a critical section. Note that we run both
802 * FAST and SLOW designated service routines.
804 if (info
->i_running
) {
809 report_stray_interrupt(intr
, info
);
811 for (rec
= *list
; rec
; rec
= nrec
) {
813 if (rec
->serializer
) {
814 lwkt_serialize_handler_call(rec
->serializer
, rec
->handler
,
815 rec
->argument
, NULL
);
817 rec
->handler(rec
->argument
, NULL
);
823 * This is our interrupt hook to add rate randomness to the random
826 if (info
->i_random
.sc_enabled
> 0)
827 add_interrupt_randomness(intr
);
830 * Unmask the interrupt to allow it to trigger again. This only
831 * applies to certain types of interrupts (typ level interrupts).
832 * This can result in the interrupt retriggering, but the retrigger
833 * will not be processed until we cycle our critical section.
835 * Only unmask interrupts while handlers are installed. It is
836 * possible to hit a situation where no handlers are installed
837 * due to a device driver livelocking and then tearing down its
838 * interrupt on close (the parallel bus being a good example).
841 machintr_intren(intr
);
844 * Do a quick exit/enter to catch any higher-priority interrupt
845 * sources, such as the statclock, so thread time accounting
846 * will still work. This may also cause an interrupt to re-trigger.
852 * LIVELOCK STATE MACHINE
854 switch(info
->i_state
) {
857 * Reset the count each second.
859 if (lseconds
!= gd
->gd_time_seconds
) {
860 lseconds
= gd
->gd_time_seconds
;
865 * If we did not exceed the frequency limit, we are done.
866 * If the interrupt has not retriggered we deschedule ourselves.
868 if (ill_count
<= livelock_limit
) {
869 if (info
->i_running
== 0) {
871 if (mpheld
&& intr_migrate
) {
876 lwkt_deschedule_self(gd
->gd_curthread
);
883 * Otherwise we are livelocked. Set up a periodic systimer
884 * to wake the thread up at the limit frequency.
886 kprintf("intr %d at %d/%d hz, livelocked limit engaged!\n",
887 intr
, ill_count
, livelock_limit
);
888 info
->i_state
= ISTATE_LIVELOCKED
;
889 if ((use_limit
= livelock_limit
) < 100)
891 else if (use_limit
> 500000)
893 systimer_init_periodic_nq(&ill_timer
, ithread_livelock_wakeup
,
894 (void *)(intptr_t)intr
, use_limit
);
896 case ISTATE_LIVELOCKED
:
898 * Wait for our periodic timer to go off. Since the interrupt
899 * has re-armed it can still set i_running, but it will not
900 * reschedule us while we are in a livelocked state.
902 lwkt_deschedule_self(gd
->gd_curthread
);
906 * Check once a second to see if the livelock condition no
909 if (lseconds
!= gd
->gd_time_seconds
) {
910 lseconds
= gd
->gd_time_seconds
;
911 if (ill_count
< livelock_lowater
) {
912 info
->i_state
= ISTATE_NORMAL
;
913 systimer_del(&ill_timer
);
914 kprintf("intr %d at %d/%d hz, livelock removed\n",
915 intr
, ill_count
, livelock_lowater
);
916 } else if (livelock_debug
== intr
||
917 (bootverbose
&& cold
)) {
918 kprintf("intr %d at %d/%d hz, in livelock\n",
919 intr
, ill_count
, livelock_lowater
);
932 * An interrupt thread is trying to get the MP lock. To avoid cpu-bound
933 * code in the kernel on cpu X from interfering we chase the MP lock.
936 intr_get_mplock(void)
940 if (intr_migrate
== 0) {
944 while (try_mplock() == 0) {
945 owner
= owner_mplock();
946 if (owner
>= 0 && owner
!= mycpu
->gd_cpuid
) {
947 lwkt_migratecpu(owner
);
948 ++intr_migrate_count
;
958 * Emergency interrupt polling thread. The thread begins execution
959 * outside a critical section with the BGL held.
961 * If emergency interrupt polling is enabled, this thread will
962 * execute all system interrupts not marked INTR_NOPOLL at the
963 * specified polling frequency.
965 * WARNING! This thread runs *ALL* interrupt service routines that
966 * are not marked INTR_NOPOLL, which basically means everything except
967 * the 8254 clock interrupt and the ATA interrupt. It has very high
968 * overhead and should only be used in situations where the machine
969 * cannot otherwise be made to work. Due to the severe performance
970 * degredation, it should not be enabled on production machines.
973 ithread_emergency(void *arg __unused
)
975 struct intr_info
*info
;
980 for (intr
= 0; intr
< max_installed_hard_intr
; ++intr
) {
981 info
= &intr_info_ary
[intr
];
982 for (rec
= info
->i_reclist
; rec
; rec
= nrec
) {
983 if ((rec
->intr_flags
& INTR_NOPOLL
) == 0) {
984 if (rec
->serializer
) {
985 lwkt_serialize_handler_call(rec
->serializer
,
986 rec
->handler
, rec
->argument
, NULL
);
988 rec
->handler(rec
->argument
, NULL
);
994 lwkt_deschedule_self(curthread
);
1000 * Systimer callback - schedule the emergency interrupt poll thread
1001 * if emergency polling is enabled.
1005 emergency_intr_timer_callback(systimer_t info
, struct intrframe
*frame __unused
)
1007 if (emergency_intr_enable
)
1008 lwkt_schedule(info
->data
);
1012 ithread_cpuid(int intr
)
1014 const struct intr_info
*info
;
1016 KKASSERT(intr
>= 0 && intr
< MAX_INTS
);
1017 info
= &intr_info_ary
[intr
];
1019 if (info
->i_state
== ISTATE_NOTHREAD
)
1021 return info
->i_thread
.td_gd
->gd_cpuid
;
1025 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt.
1026 * The data for this machine dependent, and the declarations are in machine
1027 * dependent code. The layout of intrnames and intrcnt however is machine
1030 * We do not know the length of intrcnt and intrnames at compile time, so
1031 * calculate things at run time.
1035 sysctl_intrnames(SYSCTL_HANDLER_ARGS
)
1037 struct intr_info
*info
;
1044 for (intr
= 0; error
== 0 && intr
< MAX_INTS
; ++intr
) {
1045 info
= &intr_info_ary
[intr
];
1049 for (rec
= info
->i_reclist
; rec
; rec
= rec
->next
) {
1050 ksnprintf(buf
+ len
, sizeof(buf
) - len
, "%s%s",
1051 (len
? "/" : ""), rec
->name
);
1052 len
+= strlen(buf
+ len
);
1055 ksnprintf(buf
, sizeof(buf
), "irq%d", intr
);
1058 error
= SYSCTL_OUT(req
, buf
, len
+ 1);
1064 SYSCTL_PROC(_hw
, OID_AUTO
, intrnames
, CTLTYPE_OPAQUE
| CTLFLAG_RD
,
1065 NULL
, 0, sysctl_intrnames
, "", "Interrupt Names");
1068 sysctl_intrcnt(SYSCTL_HANDLER_ARGS
)
1070 struct intr_info
*info
;
1074 for (intr
= 0; intr
< max_installed_hard_intr
; ++intr
) {
1075 info
= &intr_info_ary
[intr
];
1077 error
= SYSCTL_OUT(req
, &info
->i_count
, sizeof(info
->i_count
));
1081 for (intr
= FIRST_SOFTINT
; intr
< max_installed_soft_intr
; ++intr
) {
1082 info
= &intr_info_ary
[intr
];
1084 error
= SYSCTL_OUT(req
, &info
->i_count
, sizeof(info
->i_count
));
1092 SYSCTL_PROC(_hw
, OID_AUTO
, intrcnt
, CTLTYPE_OPAQUE
| CTLFLAG_RD
,
1093 NULL
, 0, sysctl_intrcnt
, "", "Interrupt Counts");
1096 int_moveto_destcpu(int *orig_cpuid0
, int *cpuid0
, int intr
)
1098 int orig_cpuid
= mycpuid
, cpuid
;
1102 ksnprintf(envpath
, sizeof(envpath
), "hw.irq.%d.dest", intr
);
1103 kgetenv_int(envpath
, &cpuid
);
1107 if (cpuid
!= orig_cpuid
)
1108 lwkt_migratecpu(cpuid
);
1110 *orig_cpuid0
= orig_cpuid
;
1115 int_moveto_origcpu(int orig_cpuid
, int cpuid
)
1117 if (cpuid
!= orig_cpuid
)
1118 lwkt_migratecpu(orig_cpuid
);