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intr.c revision 1.2.18.4 
      1 /*	$NetBSD: intr.c,v 1.2.18.4 2010/08/11 22:55:06 yamt Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2008 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 1.2.18.4 2010/08/11 22:55:06 yamt 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_ONLIST 0x02
     51 #define SI_KILLME 0x04
     52 
     53 struct softint {
     54 	void (*si_func)(void *);
     55 	void *si_arg;
     56 	int si_flags;
     57 	int si_level;
     58 
     59 	LIST_ENTRY(softint) si_entries;
     60 };
     61 
     62 struct softint_lev {
     63 	struct rumpuser_cv *si_cv;
     64 	LIST_HEAD(, softint) si_pending;
     65 };
     66 
     67 kcondvar_t lbolt; /* Oh Kath Ra */
     68 
     69 static u_int ticks;
     70 
     71 static u_int
     72 rumptc_get(struct timecounter *tc)
     73 {
     74 
     75 	KASSERT(rump_threads);
     76 	return ticks;
     77 }
     78 
     79 static struct timecounter rumptc = {
     80 	.tc_get_timecount	= rumptc_get,
     81 	.tc_poll_pps 		= NULL,
     82 	.tc_counter_mask	= ~0,
     83 	.tc_frequency		= 0,
     84 	.tc_name		= "rumpclk",
     85 	.tc_quality		= 0,
     86 };
     87 
     88 /*
     89  * clock "interrupt"
     90  */
     91 static void
     92 doclock(void *noarg)
     93 {
     94 	struct timespec clockbase, clockup;
     95 	struct timespec thetick, curtime;
     96 	struct rumpuser_cv *clockcv;
     97 	struct rumpuser_mtx *clockmtx;
     98 	uint64_t sec, nsec;
     99 	int error;
    100 	extern int hz;
    101 
    102 	memset(&clockup, 0, sizeof(clockup));
    103 	rumpuser_gettime(&sec, &nsec, &error);
    104 	clockbase.tv_sec = sec;
    105 	clockbase.tv_nsec = nsec;
    106 	curtime = clockbase;
    107 	thetick.tv_sec = 0;
    108 	thetick.tv_nsec = 1000000000/hz;
    109 
    110 	/* XXX: dummies */
    111 	rumpuser_cv_init(&clockcv);
    112 	rumpuser_mutex_init(&clockmtx);
    113 
    114 	rumpuser_mutex_enter(clockmtx);
    115 	for (;;) {
    116 		callout_hardclock();
    117 
    118 		/* wait until the next tick. XXX: what if the clock changes? */
    119 		while (rumpuser_cv_timedwait(clockcv, clockmtx,
    120 		    curtime.tv_sec, curtime.tv_nsec) == 0)
    121 			continue;
    122 
    123 		/* XXX: sync with a) virtual clock b) host clock */
    124 		timespecadd(&clockup, &clockbase, &curtime);
    125 		timespecadd(&clockup, &thetick, &clockup);
    126 
    127 #if 0
    128 		/* CPU_IS_PRIMARY is MD and hence unreliably correct here */
    129 		if (!CPU_IS_PRIMARY(curcpu()))
    130 			continue;
    131 #else
    132 		if (curcpu()->ci_index != 0)
    133 			continue;
    134 #endif
    135 
    136 		if ((++ticks % hz) == 0) {
    137 			cv_broadcast(&lbolt);
    138 		}
    139 		tc_ticktock();
    140 	}
    141 }
    142 
    143 /*
    144  * Soft interrupt execution thread.  This thread is pinned to the
    145  * same CPU that scheduled the interrupt, so we don't need to do
    146  * lock against si_lvl.
    147  */
    148 static void
    149 sithread(void *arg)
    150 {
    151 	struct softint *si;
    152 	void (*func)(void *) = NULL;
    153 	void *funarg;
    154 	bool mpsafe;
    155 	int mylevel = (uintptr_t)arg;
    156 	struct softint_lev *si_lvlp, *si_lvl;
    157 	struct cpu_data *cd = &curcpu()->ci_data;
    158 
    159 	si_lvlp = cd->cpu_softcpu;
    160 	si_lvl = &si_lvlp[mylevel];
    161 
    162 	for (;;) {
    163 		if (!LIST_EMPTY(&si_lvl->si_pending)) {
    164 			si = LIST_FIRST(&si_lvl->si_pending);
    165 			func = si->si_func;
    166 			funarg = si->si_arg;
    167 			mpsafe = si->si_flags & SI_MPSAFE;
    168 
    169 			si->si_flags &= ~SI_ONLIST;
    170 			LIST_REMOVE(si, si_entries);
    171 			if (si->si_flags & SI_KILLME) {
    172 				softint_disestablish(si);
    173 				continue;
    174 			}
    175 		} else {
    176 			rump_schedlock_cv_wait(si_lvl->si_cv);
    177 			continue;
    178 		}
    179 
    180 		if (!mpsafe)
    181 			KERNEL_LOCK(1, curlwp);
    182 		func(funarg);
    183 		if (!mpsafe)
    184 			KERNEL_UNLOCK_ONE(curlwp);
    185 	}
    186 
    187 	panic("sithread unreachable");
    188 }
    189 
    190 void
    191 rump_intr_init()
    192 {
    193 
    194 	cv_init(&lbolt, "oh kath ra");
    195 }
    196 
    197 void
    198 softint_init(struct cpu_info *ci)
    199 {
    200 	struct cpu_data *cd = &ci->ci_data;
    201 	struct softint_lev *slev;
    202 	int rv, i;
    203 
    204 	if (!rump_threads)
    205 		return;
    206 
    207 	/* XXX */
    208 	if (ci->ci_index == 0) {
    209 		rumptc.tc_frequency = hz;
    210 		tc_init(&rumptc);
    211 	}
    212 
    213 	slev = kmem_alloc(sizeof(struct softint_lev) * SOFTINT_COUNT, KM_SLEEP);
    214 	for (i = 0; i < SOFTINT_COUNT; i++) {
    215 		rumpuser_cv_init(&slev[i].si_cv);
    216 		LIST_INIT(&slev[i].si_pending);
    217 	}
    218 	cd->cpu_softcpu = slev;
    219 
    220 	/* softint might run on different physical CPU */
    221 	membar_sync();
    222 
    223 	for (i = 0; i < SOFTINT_COUNT; i++) {
    224 		rv = kthread_create(PRI_NONE,
    225 		    KTHREAD_MPSAFE | KTHREAD_INTR, ci,
    226 		    sithread, (void *)(uintptr_t)i,
    227 		    NULL, "rsi%d/%d", ci->ci_index, i);
    228 	}
    229 
    230 	rv = kthread_create(PRI_NONE, KTHREAD_MPSAFE,
    231 	    ci, doclock, NULL, NULL, "rumpclk%d", ci->ci_index);
    232 	if (rv)
    233 		panic("clock thread creation failed: %d", rv);
    234 }
    235 
    236 /*
    237  * Soft interrupts bring two choices.  If we are running with thread
    238  * support enabled, defer execution, otherwise execute in place.
    239  * See softint_schedule().
    240  *
    241  * As there is currently no clear concept of when a thread finishes
    242  * work (although rump_clear_curlwp() is close), simply execute all
    243  * softints in the timer thread.  This is probably not the most
    244  * efficient method, but good enough for now.
    245  */
    246 void *
    247 softint_establish(u_int flags, void (*func)(void *), void *arg)
    248 {
    249 	struct softint *si;
    250 
    251 	si = malloc(sizeof(*si), M_TEMP, M_WAITOK);
    252 	si->si_func = func;
    253 	si->si_arg = arg;
    254 	si->si_flags = flags & SOFTINT_MPSAFE ? SI_MPSAFE : 0;
    255 	si->si_level = flags & SOFTINT_LVLMASK;
    256 	KASSERT(si->si_level < SOFTINT_COUNT);
    257 
    258 	return si;
    259 }
    260 
    261 void
    262 softint_schedule(void *arg)
    263 {
    264 	struct softint *si = arg;
    265 	struct cpu_data *cd = &curcpu()->ci_data;
    266 	struct softint_lev *si_lvl = cd->cpu_softcpu;
    267 
    268 	if (!rump_threads) {
    269 		si->si_func(si->si_arg);
    270 	} else {
    271 		if (!(si->si_flags & SI_ONLIST)) {
    272 			LIST_INSERT_HEAD(&si_lvl[si->si_level].si_pending,
    273 			    si, si_entries);
    274 			si->si_flags |= SI_ONLIST;
    275 		}
    276 	}
    277 }
    278 
    279 /* flimsy disestablish: should wait for softints to finish */
    280 void
    281 softint_disestablish(void *cook)
    282 {
    283 	struct softint *si = cook;
    284 
    285 	if (si->si_flags & SI_ONLIST) {
    286 		si->si_flags |= SI_KILLME;
    287 		return;
    288 	}
    289 	free(si, M_TEMP);
    290 }
    291 
    292 void
    293 rump_softint_run(struct cpu_info *ci)
    294 {
    295 	struct cpu_data *cd = &ci->ci_data;
    296 	struct softint_lev *si_lvl = cd->cpu_softcpu;
    297 	int i;
    298 
    299 	if (!rump_threads)
    300 		return;
    301 
    302 	for (i = 0; i < SOFTINT_COUNT; i++) {
    303 		if (!LIST_EMPTY(&si_lvl[i].si_pending))
    304 			rumpuser_cv_signal(si_lvl[i].si_cv);
    305 	}
    306 }
    307 
    308 bool
    309 cpu_intr_p(void)
    310 {
    311 
    312 	return false;
    313 }
    314 
    315 bool
    316 cpu_softintr_p(void)
    317 {
    318 
    319 	return curlwp->l_pflag & LP_INTR;
    320 }
    321