1/* $NetBSD: intr.c,v 1.56 2020/11/01 20:58:38 christos Exp $ */ 2 3/* 4 * Copyright (c) 2008-2010, 2015 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 1.56 2020/11/01 20:58:38 christos 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-sys/kern.h> 42 43#include <rump/rumpuser.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 bool sip_onlist_cpu; 66 67 TAILQ_ENTRY(softint_percpu) sip_entries; /* scheduled */ 68 TAILQ_ENTRY(softint_percpu) sip_entries_cpu; /* to be scheduled */ 69}; 70 71struct softint_lev { 72 struct rumpuser_cv *si_cv; 73 TAILQ_HEAD(, softint_percpu) si_pending; 74}; 75 76static TAILQ_HEAD(, softint_percpu) sicpupending \ 77 = TAILQ_HEAD_INITIALIZER(sicpupending); 78static struct rumpuser_mtx *sicpumtx; 79static struct rumpuser_cv *sicpucv; 80 81kcondvar_t lbolt; /* Oh Kath Ra */ 82 83static int ncpu_final; 84 85void noclock(void); void noclock(void) {return;} 86__strong_alias(sched_schedclock,noclock); 87__strong_alias(cpu_initclocks,noclock); 88__strong_alias(addupc_intr,noclock); 89__strong_alias(sched_tick,noclock); 90__strong_alias(setstatclockrate,noclock); 91 92/* 93 * clock "interrupt" 94 */ 95static void 96doclock(void *noarg) 97{ 98 struct timespec thetick, curclock; 99 struct clockframe *clkframe; 100 int64_t sec; 101 long nsec; 102 int error; 103 struct cpu_info *ci = curcpu(); 104 105 error = rumpuser_clock_gettime(RUMPUSER_CLOCK_ABSMONO, &sec, &nsec); 106 if (error) 107 panic("clock: cannot get monotonic time"); 108 109 curclock.tv_sec = sec; 110 curclock.tv_nsec = nsec; 111 thetick.tv_sec = 0; 112 thetick.tv_nsec = 1000000000/hz; 113 114 /* generate dummy clockframe for hardclock to consume */ 115 clkframe = rump_cpu_makeclockframe(); 116 117 for (;;) { 118 int lbolt_ticks = 0; 119 120 hardclock(clkframe); 121 if (CPU_IS_PRIMARY(ci)) { 122 if (++lbolt_ticks >= hz) { 123 lbolt_ticks = 0; 124 cv_broadcast(&lbolt); 125 } 126 } 127 128 error = rumpuser_clock_sleep(RUMPUSER_CLOCK_ABSMONO, 129 curclock.tv_sec, curclock.tv_nsec); 130 if (error) { 131 panic("rumpuser_clock_sleep failed with error %d", 132 error); 133 } 134 timespecadd(&curclock, &thetick, &curclock); 135 } 136} 137 138/* 139 * Soft interrupt execution thread. This thread is pinned to the 140 * same CPU that scheduled the interrupt, so we don't need to do 141 * lock against si_lvl. 142 */ 143static void 144sithread(void *arg) 145{ 146 struct softint_percpu *sip; 147 struct softint *si; 148 void (*func)(void *) = NULL; 149 void *funarg; 150 bool mpsafe; 151 int mylevel = (uintptr_t)arg; 152 struct softint_lev *si_lvlp, *si_lvl; 153 struct cpu_data *cd = &curcpu()->ci_data; 154 155 si_lvlp = cd->cpu_softcpu; 156 si_lvl = &si_lvlp[mylevel]; 157 158 for (;;) { 159 if (!TAILQ_EMPTY(&si_lvl->si_pending)) { 160 sip = TAILQ_FIRST(&si_lvl->si_pending); 161 si = sip->sip_parent; 162 163 func = si->si_func; 164 funarg = si->si_arg; 165 mpsafe = si->si_flags & SI_MPSAFE; 166 167 sip->sip_onlist = false; 168 TAILQ_REMOVE(&si_lvl->si_pending, sip, sip_entries); 169 if (si->si_flags & SI_KILLME) { 170 softint_disestablish(si); 171 continue; 172 } 173 } else { 174 rump_schedlock_cv_wait(si_lvl->si_cv); 175 continue; 176 } 177 178 if (!mpsafe) 179 KERNEL_LOCK(1, curlwp); 180 func(funarg); 181 if (!mpsafe) 182 KERNEL_UNLOCK_ONE(curlwp); 183 } 184 185 panic("sithread unreachable"); 186} 187 188/* 189 * Helper for softint_schedule_cpu() 190 */ 191static void 192sithread_cpu_bouncer(void *arg) 193{ 194 struct lwp *me; 195 196 me = curlwp; 197 me->l_pflag |= LP_BOUND; 198 199 rump_unschedule(); 200 for (;;) { 201 struct softint_percpu *sip; 202 struct softint *si; 203 struct cpu_info *ci; 204 unsigned int cidx; 205 206 rumpuser_mutex_enter_nowrap(sicpumtx); 207 while (TAILQ_EMPTY(&sicpupending)) { 208 rumpuser_cv_wait_nowrap(sicpucv, sicpumtx); 209 } 210 sip = TAILQ_FIRST(&sicpupending); 211 TAILQ_REMOVE(&sicpupending, sip, sip_entries_cpu); 212 sip->sip_onlist_cpu = false; 213 rumpuser_mutex_exit(sicpumtx); 214 215 /* 216 * ok, now figure out which cpu we need the softint to 217 * be handled on 218 */ 219 si = sip->sip_parent; 220 cidx = sip - si->si_entry; 221 ci = cpu_lookup(cidx); 222 me->l_target_cpu = ci; 223 224 /* schedule ourselves there, and then schedule the softint */ 225 rump_schedule(); 226 KASSERT(curcpu() == ci); 227 softint_schedule(si); 228 rump_unschedule(); 229 } 230 panic("sithread_cpu_bouncer unreasonable"); 231} 232 233static kmutex_t sithr_emtx; 234static unsigned int sithr_est; 235static int sithr_canest; 236 237/* 238 * Create softint handler threads when the softint for each respective 239 * level is established for the first time. Most rump kernels don't 240 * need at least half of the softint levels, so on-demand saves bootstrap 241 * time and memory resources. Note, though, that this routine may be 242 * called before it's possible to call kthread_create(). Creation of 243 * those softints (SOFTINT_CLOCK, as of writing this) will be deferred 244 * to until softint_init() is called for the main CPU. 245 */ 246static void 247sithread_establish(int level) 248{ 249 int docreate, rv; 250 int lvlbit = 1<<level; 251 int i; 252 253 KASSERT((level & ~SOFTINT_LVLMASK) == 0); 254 if (__predict_true(sithr_est & lvlbit)) 255 return; 256 257 mutex_enter(&sithr_emtx); 258 docreate = (sithr_est & lvlbit) == 0 && sithr_canest; 259 sithr_est |= lvlbit; 260 mutex_exit(&sithr_emtx); 261 262 if (docreate) { 263 for (i = 0; i < ncpu_final; i++) { 264 if ((rv = kthread_create(PRI_NONE, 265 KTHREAD_MPSAFE | KTHREAD_INTR, 266 cpu_lookup(i), sithread, (void *)(uintptr_t)level, 267 NULL, "rsi%d/%d", i, level)) != 0) 268 panic("softint thread create failed: %d", rv); 269 } 270 } 271} 272 273void 274rump_intr_init(int numcpu) 275{ 276 277 cv_init(&lbolt, "oh kath ra"); 278 mutex_init(&sithr_emtx, MUTEX_DEFAULT, IPL_NONE); 279 ncpu_final = numcpu; 280} 281 282void 283softint_init(struct cpu_info *ci) 284{ 285 struct cpu_data *cd = &ci->ci_data; 286 struct softint_lev *slev; 287 int rv, i; 288 289 if (!rump_threads) 290 return; 291 292 slev = kmem_alloc(sizeof(struct softint_lev) * SOFTINT_COUNT, KM_SLEEP); 293 for (i = 0; i < SOFTINT_COUNT; i++) { 294 rumpuser_cv_init(&slev[i].si_cv); 295 TAILQ_INIT(&slev[i].si_pending); 296 } 297 cd->cpu_softcpu = slev; 298 299 /* overloaded global init ... */ 300 /* XXX: should be done the last time we are called */ 301 if (ci->ci_index == 0) { 302 int sithr_swap; 303 304 /* pretend that we have our own for these */ 305 stathz = 1; 306 schedhz = 1; 307 profhz = 1; 308 309 initclocks(); 310 311 /* create deferred softint threads */ 312 mutex_enter(&sithr_emtx); 313 sithr_swap = sithr_est; 314 sithr_est = 0; 315 sithr_canest = 1; 316 mutex_exit(&sithr_emtx); 317 for (i = 0; i < SOFTINT_COUNT; i++) { 318 if (sithr_swap & (1<<i)) 319 sithread_establish(i); 320 } 321 } 322 323 /* well, not really a "soft" interrupt ... */ 324 if ((rv = kthread_create(PRI_NONE, KTHREAD_MPSAFE, 325 ci, doclock, NULL, NULL, "rumpclk%d", ci->ci_index)) != 0) 326 panic("clock thread creation failed: %d", rv); 327 328 /* not one either, but at least a softint helper */ 329 rumpuser_mutex_init(&sicpumtx, RUMPUSER_MTX_SPIN); 330 rumpuser_cv_init(&sicpucv); 331 if ((rv = kthread_create(PRI_NONE, KTHREAD_MPSAFE, 332 NULL, sithread_cpu_bouncer, NULL, NULL, "sipbnc")) != 0) 333 panic("softint cpu bouncer creation failed: %d", rv); 334} 335 336void * 337softint_establish(u_int flags, void (*func)(void *), void *arg) 338{ 339 struct softint *si; 340 struct softint_percpu *sip; 341 int level = flags & SOFTINT_LVLMASK; 342 int i; 343 344 si = malloc(sizeof(*si), M_TEMP, M_WAITOK); 345 si->si_func = func; 346 si->si_arg = arg; 347 si->si_flags = flags & SOFTINT_MPSAFE ? SI_MPSAFE : 0; 348 si->si_level = level; 349 KASSERT(si->si_level < SOFTINT_COUNT); 350 si->si_entry = malloc(sizeof(*si->si_entry) * ncpu_final, 351 M_TEMP, M_WAITOK | M_ZERO); 352 for (i = 0; i < ncpu_final; i++) { 353 sip = &si->si_entry[i]; 354 sip->sip_parent = si; 355 } 356 sithread_establish(level); 357 358 return si; 359} 360 361static struct softint_percpu * 362sitosip(struct softint *si, struct cpu_info *ci) 363{ 364 365 return &si->si_entry[ci->ci_index]; 366} 367 368/* 369 * Soft interrupts bring two choices. If we are running with thread 370 * support enabled, defer execution, otherwise execute in place. 371 */ 372 373void 374softint_schedule(void *arg) 375{ 376 struct softint *si = arg; 377 struct cpu_info *ci = curcpu(); 378 struct softint_percpu *sip = sitosip(si, ci); 379 struct cpu_data *cd = &ci->ci_data; 380 struct softint_lev *si_lvl = cd->cpu_softcpu; 381 382 if (!rump_threads) { 383 si->si_func(si->si_arg); 384 } else { 385 if (!sip->sip_onlist) { 386 TAILQ_INSERT_TAIL(&si_lvl[si->si_level].si_pending, 387 sip, sip_entries); 388 sip->sip_onlist = true; 389 } 390 } 391} 392 393/* 394 * Like softint_schedule(), except schedule softint to be handled on 395 * the core designated by ci_tgt instead of the core the call is made on. 396 * 397 * Unlike softint_schedule(), the performance is not important 398 * (unless ci_tgt == curcpu): high-performance rump kernel I/O stacks 399 * should arrange data to already be on the right core at the driver 400 * layer. 401 */ 402void 403softint_schedule_cpu(void *arg, struct cpu_info *ci_tgt) 404{ 405 struct softint *si = arg; 406 struct cpu_info *ci_cur = curcpu(); 407 struct softint_percpu *sip; 408 409 KASSERT(rump_threads); 410 411 /* preferred case (which can be optimized some day) */ 412 if (ci_cur == ci_tgt) { 413 softint_schedule(si); 414 return; 415 } 416 417 /* 418 * no? then it's softint turtles all the way down 419 */ 420 421 sip = sitosip(si, ci_tgt); 422 rumpuser_mutex_enter_nowrap(sicpumtx); 423 if (sip->sip_onlist_cpu) { 424 rumpuser_mutex_exit(sicpumtx); 425 return; 426 } 427 TAILQ_INSERT_TAIL(&sicpupending, sip, sip_entries_cpu); 428 sip->sip_onlist_cpu = true; 429 rumpuser_cv_signal(sicpucv); 430 rumpuser_mutex_exit(sicpumtx); 431} 432 433/* 434 * flimsy disestablish: should wait for softints to finish. 435 */ 436void 437softint_disestablish(void *cook) 438{ 439 struct softint *si = cook; 440 int i; 441 442 for (i = 0; i < ncpu_final; i++) { 443 struct softint_percpu *sip; 444 445 sip = &si->si_entry[i]; 446 if (sip->sip_onlist) { 447 si->si_flags |= SI_KILLME; 448 return; 449 } 450 } 451 free(si->si_entry, M_TEMP); 452 free(si, M_TEMP); 453} 454 455void 456rump_softint_run(struct cpu_info *ci) 457{ 458 struct cpu_data *cd = &ci->ci_data; 459 struct softint_lev *si_lvl = cd->cpu_softcpu; 460 int i; 461 462 if (!rump_threads) 463 return; 464 465 for (i = 0; i < SOFTINT_COUNT; i++) { 466 if (!TAILQ_EMPTY(&si_lvl[i].si_pending)) 467 rump_schedlock_cv_signal(ci, si_lvl[i].si_cv); 468 } 469} 470 471bool 472cpu_intr_p(void) 473{ 474 475 return false; 476} 477