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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 
     52 struct softint_percpu;
     53 struct 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 
     62 struct softint_percpu {
     63 	struct softint *sip_parent;
     64 	bool sip_onlist;
     65 
     66 	LIST_ENTRY(softint_percpu) sip_entries;
     67 };
     68 
     69 struct softint_lev {
     70 	struct rumpuser_cv *si_cv;
     71 	LIST_HEAD(, softint_percpu) si_pending;
     72 };
     73 
     74 kcondvar_t lbolt; /* Oh Kath Ra */
     75 
     76 static u_int ticks;
     77 static int ncpu_final;
     78 
     79 static u_int
     80 rumptc_get(struct timecounter *tc)
     81 {
     82 
     83 	KASSERT(rump_threads);
     84 	return ticks;
     85 }
     86 
     87 static 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  */
     99 static void
    100 doclock(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  */
    146 static void
    147 sithread(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 
    191 static kmutex_t sithr_emtx;
    192 static unsigned int sithr_est;
    193 static 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  */
    204 static void
    205 sithread_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 
    231 void
    232 rump_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 
    240 void
    241 softint_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 
    282 void *
    283 softint_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 
    312 void
    313 softint_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  */
    334 void
    335 softint_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 
    353 void
    354 rump_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 
    369 bool
    370 cpu_intr_p(void)
    371 {
    372 
    373 	return false;
    374 }
    375 
    376 bool
    377 cpu_softintr_p(void)
    378 {
    379 
    380 	return curlwp->l_pflag & LP_INTR;
    381 }
    382