intr.c revision 1.41 
1/*	$NetBSD: intr.c,v 1.41 2013/11/11 23:06:40 pooka Exp $	*/
2
3/*
4 * Copyright (c) 2008-2010 Antti Kantee.  All Rights Reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
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.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__KERNEL_RCSID(0, "$NetBSD: intr.c,v 1.41 2013/11/11 23:06:40 pooka Exp $");
30
31#include <sys/param.h>
32#include <sys/atomic.h>
33#include <sys/cpu.h>
34#include <sys/kernel.h>
35#include <sys/kmem.h>
36#include <sys/kthread.h>
37#include <sys/malloc.h>
38#include <sys/intr.h>
39#include <sys/timetc.h>
40
41#include <rump/rumpuser.h>
42
43#include "rump_private.h"
44
45/*
46 * Interrupt simulator.  It executes hardclock() and softintrs.
47 */
48
49#define SI_MPSAFE 0x01
50#define SI_KILLME 0x02
51
52struct softint_percpu;
53struct softint {
54	void (*si_func)(void *);
55	void *si_arg;
56	int si_flags;
57	int si_level;
58
59	struct softint_percpu *si_entry; /* [0,ncpu-1] */
60};
61
62struct softint_percpu {
63	struct softint *sip_parent;
64	bool sip_onlist;
65
66	LIST_ENTRY(softint_percpu) sip_entries;
67};
68
69struct softint_lev {
70	struct rumpuser_cv *si_cv;
71	LIST_HEAD(, softint_percpu) si_pending;
72};
73
74kcondvar_t lbolt; /* Oh Kath Ra */
75
76static u_int ticks;
77static int ncpu_final;
78
79static u_int
80rumptc_get(struct timecounter *tc)
81{
82
83	KASSERT(rump_threads);
84	return ticks;
85}
86
87static struct timecounter rumptc = {
88	.tc_get_timecount	= rumptc_get,
89	.tc_poll_pps 		= NULL,
90	.tc_counter_mask	= ~0,
91	.tc_frequency		= 0,
92	.tc_name		= "rumpclk",
93	.tc_quality		= 0,
94};
95
96/*
97 * clock "interrupt"
98 */
99static void
100doclock(void *noarg)
101{
102	struct timespec thetick, curclock;
103	int64_t sec;
104	long nsec;
105	int error;
106	extern int hz;
107
108	error = rumpuser_clock_gettime(RUMPUSER_CLOCK_ABSMONO, &sec, &nsec);
109	if (error)
110		panic("clock: cannot get monotonic time");
111
112	curclock.tv_sec = sec;
113	curclock.tv_nsec = nsec;
114	thetick.tv_sec = 0;
115	thetick.tv_nsec = 1000000000/hz;
116
117	for (;;) {
118		callout_hardclock();
119
120		error = rumpuser_clock_sleep(RUMPUSER_CLOCK_ABSMONO,
121		    curclock.tv_sec, curclock.tv_nsec);
122		KASSERT(!error);
123		timespecadd(&curclock, &thetick, &curclock);
124
125#if 0
126		/* CPU_IS_PRIMARY is MD and hence unreliably correct here */
127		if (!CPU_IS_PRIMARY(curcpu()))
128			continue;
129#else
130		if (curcpu()->ci_index != 0)
131			continue;
132#endif
133
134		if ((++ticks % hz) == 0) {
135			cv_broadcast(&lbolt);
136		}
137		tc_ticktock();
138	}
139}
140
141/*
142 * Soft interrupt execution thread.  This thread is pinned to the
143 * same CPU that scheduled the interrupt, so we don't need to do
144 * lock against si_lvl.
145 */
146static void
147sithread(void *arg)
148{
149	struct softint_percpu *sip;
150	struct softint *si;
151	void (*func)(void *) = NULL;
152	void *funarg;
153	bool mpsafe;
154	int mylevel = (uintptr_t)arg;
155	struct softint_lev *si_lvlp, *si_lvl;
156	struct cpu_data *cd = &curcpu()->ci_data;
157
158	si_lvlp = cd->cpu_softcpu;
159	si_lvl = &si_lvlp[mylevel];
160
161	for (;;) {
162		if (!LIST_EMPTY(&si_lvl->si_pending)) {
163			sip = LIST_FIRST(&si_lvl->si_pending);
164			si = sip->sip_parent;
165
166			func = si->si_func;
167			funarg = si->si_arg;
168			mpsafe = si->si_flags & SI_MPSAFE;
169
170			sip->sip_onlist = false;
171			LIST_REMOVE(sip, sip_entries);
172			if (si->si_flags & SI_KILLME) {
173				softint_disestablish(si);
174				continue;
175			}
176		} else {
177			rump_schedlock_cv_wait(si_lvl->si_cv);
178			continue;
179		}
180
181		if (!mpsafe)
182			KERNEL_LOCK(1, curlwp);
183		func(funarg);
184		if (!mpsafe)
185			KERNEL_UNLOCK_ONE(curlwp);
186	}
187
188	panic("sithread unreachable");
189}
190
191static kmutex_t sithr_emtx;
192static unsigned int sithr_est;
193static int sithr_canest;
194
195/*
196 * Create softint handler threads when the softint for each respective
197 * level is established for the first time.  Most rump kernels don't
198 * need at least half of the softint levels, so on-demand saves bootstrap
199 * time and memory resources.  Note, though, that this routine may be
200 * called before it's possible to call kthread_create().  Creation of
201 * those softints (SOFTINT_CLOCK, as of writing this) will be deferred
202 * to until softint_init() is called for the main CPU.
203 */
204static void
205sithread_establish(int level)
206{
207	int docreate, rv;
208	int lvlbit = 1<<level;
209	int i;
210
211	KASSERT((level & ~SOFTINT_LVLMASK) == 0);
212	if (__predict_true(sithr_est & lvlbit))
213		return;
214
215	mutex_enter(&sithr_emtx);
216	docreate = (sithr_est & lvlbit) == 0 && sithr_canest;
217	sithr_est |= lvlbit;
218	mutex_exit(&sithr_emtx);
219
220	if (docreate) {
221		for (i = 0; i < ncpu_final; i++) {
222			if ((rv = kthread_create(PRI_NONE,
223			    KTHREAD_MPSAFE | KTHREAD_INTR,
224			    cpu_lookup(i), sithread, (void *)(uintptr_t)level,
225			    NULL, "rsi%d/%d", i, level)) != 0)
226				panic("softint thread create failed: %d", rv);
227		}
228	}
229}
230
231void
232rump_intr_init(int numcpu)
233{
234
235	cv_init(&lbolt, "oh kath ra");
236	mutex_init(&sithr_emtx, MUTEX_DEFAULT, IPL_NONE);
237	ncpu_final = numcpu;
238}
239
240void
241softint_init(struct cpu_info *ci)
242{
243	struct cpu_data *cd = &ci->ci_data;
244	struct softint_lev *slev;
245	int rv, i;
246
247	if (!rump_threads)
248		return;
249
250	/* overloaded global init ... */
251	if (ci->ci_index == 0) {
252		int sithr_swap;
253
254		rumptc.tc_frequency = hz;
255		tc_init(&rumptc);
256
257		/* create deferred softint threads */
258		mutex_enter(&sithr_emtx);
259		sithr_swap = sithr_est;
260		sithr_est = 0;
261		sithr_canest = 1;
262		mutex_exit(&sithr_emtx);
263		for (i = 0; i < SOFTINT_COUNT; i++) {
264			if (sithr_swap & (1<<i))
265				sithread_establish(i);
266		}
267	}
268
269	slev = kmem_alloc(sizeof(struct softint_lev) * SOFTINT_COUNT, KM_SLEEP);
270	for (i = 0; i < SOFTINT_COUNT; i++) {
271		rumpuser_cv_init(&slev[i].si_cv);
272		LIST_INIT(&slev[i].si_pending);
273	}
274	cd->cpu_softcpu = slev;
275
276	/* well, not really a "soft" interrupt ... */
277	if ((rv = kthread_create(PRI_NONE, KTHREAD_MPSAFE,
278	    ci, doclock, NULL, NULL, "rumpclk%d", ci->ci_index)) != 0)
279		panic("clock thread creation failed: %d", rv);
280}
281
282void *
283softint_establish(u_int flags, void (*func)(void *), void *arg)
284{
285	struct softint *si;
286	struct softint_percpu *sip;
287	int level = flags & SOFTINT_LVLMASK;
288	int i;
289
290	si = malloc(sizeof(*si), M_TEMP, M_WAITOK);
291	si->si_func = func;
292	si->si_arg = arg;
293	si->si_flags = flags & SOFTINT_MPSAFE ? SI_MPSAFE : 0;
294	si->si_level = level;
295	KASSERT(si->si_level < SOFTINT_COUNT);
296	si->si_entry = malloc(sizeof(*si->si_entry) * ncpu_final,
297	    M_TEMP, M_WAITOK | M_ZERO);
298	for (i = 0; i < ncpu_final; i++) {
299		sip = &si->si_entry[i];
300		sip->sip_parent = si;
301	}
302	sithread_establish(level);
303
304	return si;
305}
306
307/*
308 * Soft interrupts bring two choices.  If we are running with thread
309 * support enabled, defer execution, otherwise execute in place.
310 */
311
312void
313softint_schedule(void *arg)
314{
315	struct softint *si = arg;
316	struct softint_percpu *sip = &si->si_entry[curcpu()->ci_index];
317	struct cpu_data *cd = &curcpu()->ci_data;
318	struct softint_lev *si_lvl = cd->cpu_softcpu;
319
320	if (!rump_threads) {
321		si->si_func(si->si_arg);
322	} else {
323		if (!sip->sip_onlist) {
324			LIST_INSERT_HEAD(&si_lvl[si->si_level].si_pending,
325			    sip, sip_entries);
326			sip->sip_onlist = true;
327		}
328	}
329}
330
331/*
332 * flimsy disestablish: should wait for softints to finish.
333 */
334void
335softint_disestablish(void *cook)
336{
337	struct softint *si = cook;
338	int i;
339
340	for (i = 0; i < ncpu_final; i++) {
341		struct softint_percpu *sip;
342
343		sip = &si->si_entry[i];
344		if (sip->sip_onlist) {
345			si->si_flags |= SI_KILLME;
346			return;
347		}
348	}
349	free(si->si_entry, M_TEMP);
350	free(si, M_TEMP);
351}
352
353void
354rump_softint_run(struct cpu_info *ci)
355{
356	struct cpu_data *cd = &ci->ci_data;
357	struct softint_lev *si_lvl = cd->cpu_softcpu;
358	int i;
359
360	if (!rump_threads)
361		return;
362
363	for (i = 0; i < SOFTINT_COUNT; i++) {
364		if (!LIST_EMPTY(&si_lvl[i].si_pending))
365			rumpuser_cv_signal(si_lvl[i].si_cv);
366	}
367}
368
369bool
370cpu_intr_p(void)
371{
372
373	return false;
374}
375
376bool
377cpu_softintr_p(void)
378{
379
380	return curlwp->l_pflag & LP_INTR;
381}
382