1 /* 2 * Copyright (c) 2003 Matthew Dillon <dillon@backplane.com> All rights reserved. 3 * Copyright (c) 1997, Stefan Esser <se@freebsd.org> All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * 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 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. 25 * 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 1.18 2004/06/28 05:02:56 dillon Exp $ 28 * 29 */ 30 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> 37 #include <sys/proc.h> 38 #include <sys/thread2.h> 39 #include <sys/random.h> 40 41 #include <machine/ipl.h> 42 43 #include <sys/interrupt.h> 44 45 typedef struct intrec { 46 struct intrec *next; 47 inthand2_t *handler; 48 void *argument; 49 const char *name; 50 int intr; 51 } intrec_t; 52 53 static intrec_t *intlists[NHWI+NSWI]; 54 static thread_t ithreads[NHWI+NSWI]; 55 static struct thread ithread_ary[NHWI+NSWI]; 56 static struct random_softc irandom_ary[NHWI+NSWI]; 57 static int irunning[NHWI+NSWI]; 58 static u_int ill_count[NHWI+NSWI]; /* interrupt livelock counter */ 59 static u_int ill_ticks[NHWI+NSWI]; /* track elapsed to calculate freq */ 60 static u_int ill_delta[NHWI+NSWI]; /* track elapsed to calculate freq */ 61 static int ill_state[NHWI+NSWI]; /* current state */ 62 static struct systimer ill_timer[NHWI+NSWI]; /* enforced freq. timer */ 63 static struct systimer ill_rtimer[NHWI+NSWI]; /* recovery timer */ 64 65 #define LIVELOCK_NONE 0 66 #define LIVELOCK_LIMITED 1 67 68 static int livelock_limit = 50000; 69 static int livelock_fallback = 20000; 70 SYSCTL_INT(_kern, OID_AUTO, livelock_limit, 71 CTLFLAG_RW, &livelock_limit, 0, "Livelock interrupt rate limit"); 72 SYSCTL_INT(_kern, OID_AUTO, livelock_fallback, 73 CTLFLAG_RW, &livelock_fallback, 0, "Livelock interrupt fallback rate"); 74 75 static void ithread_handler(void *arg); 76 77 thread_t 78 register_swi(int intr, inthand2_t *handler, void *arg, const char *name) 79 { 80 if (intr < NHWI || intr >= NHWI + NSWI) 81 panic("register_swi: bad intr %d", intr); 82 return(register_int(intr, handler, arg, name)); 83 } 84 85 thread_t 86 register_int(int intr, inthand2_t *handler, void *arg, const char *name) 87 { 88 intrec_t **list; 89 intrec_t *rec; 90 thread_t td; 91 92 if (intr < 0 || intr >= NHWI + NSWI) 93 panic("register_int: bad intr %d", intr); 94 95 rec = malloc(sizeof(intrec_t), M_DEVBUF, M_NOWAIT); 96 if (rec == NULL) 97 panic("register_swi: malloc failed"); 98 rec->handler = handler; 99 rec->argument = arg; 100 rec->name = name; 101 rec->intr = intr; 102 rec->next = NULL; 103 104 list = &intlists[intr]; 105 106 /* 107 * Create an interrupt thread if necessary, leave it in an unscheduled 108 * state. The kthread restore function exits a critical section before 109 * starting the function so we need *TWO* critical sections in order 110 * for the handler to begin running in one. 111 */ 112 if ((td = ithreads[intr]) == NULL) { 113 lwkt_create((void *)ithread_handler, (void *)intr, &ithreads[intr], 114 &ithread_ary[intr], TDF_STOPREQ|TDF_INTTHREAD, -1, 115 "ithread %d", intr); 116 td = ithreads[intr]; 117 if (intr >= NHWI && intr < NHWI + NSWI) 118 lwkt_setpri(td, TDPRI_SOFT_NORM + TDPRI_CRIT * 2); 119 else 120 lwkt_setpri(td, TDPRI_INT_MED + TDPRI_CRIT * 2); 121 } 122 123 /* 124 * Add the record to the interrupt list 125 */ 126 crit_enter(); /* token */ 127 while (*list != NULL) 128 list = &(*list)->next; 129 *list = rec; 130 crit_exit(); 131 return(td); 132 } 133 134 void 135 unregister_swi(int intr, inthand2_t *handler) 136 { 137 if (intr < NHWI || intr >= NHWI + NSWI) 138 panic("register_swi: bad intr %d", intr); 139 unregister_int(intr, handler); 140 } 141 142 void 143 unregister_int(int intr, inthand2_t handler) 144 { 145 intrec_t **list; 146 intrec_t *rec; 147 148 if (intr < 0 || intr > NHWI + NSWI) 149 panic("register_int: bad intr %d", intr); 150 list = &intlists[intr]; 151 crit_enter(); 152 while ((rec = *list) != NULL) { 153 if (rec->handler == (void *)handler) { 154 *list = rec->next; 155 break; 156 } 157 list = &rec->next; 158 } 159 crit_exit(); 160 if (rec != NULL) { 161 free(rec, M_DEVBUF); 162 } else { 163 printf("warning: unregister_int: int %d handler %p not found\n", 164 intr, handler); 165 } 166 } 167 168 void 169 swi_setpriority(int intr, int pri) 170 { 171 struct thread *td; 172 173 if (intr < NHWI || intr >= NHWI + NSWI) 174 panic("register_swi: bad intr %d", intr); 175 if ((td = ithreads[intr]) != NULL) 176 lwkt_setpri(td, pri); 177 } 178 179 void 180 register_randintr(int intr) 181 { 182 struct random_softc *sc = &irandom_ary[intr]; 183 sc->sc_intr = intr; 184 sc->sc_enabled = 1; 185 } 186 187 void 188 unregister_randintr(int intr) 189 { 190 struct random_softc *sc = &irandom_ary[intr]; 191 sc->sc_enabled = 0; 192 } 193 194 /* 195 * Dispatch an interrupt. If there's nothing to do we have a stray 196 * interrupt and can just return, leaving the interrupt masked. 197 * 198 * We need to schedule the interrupt and set its irunning[] bit. If 199 * we are not on the interrupt thread's cpu we have to send a message 200 * to the correct cpu that will issue the desired action (interlocking 201 * with the interrupt thread's critical section). 202 * 203 * We are NOT in a critical section, which will allow the scheduled 204 * interrupt to preempt us. The MP lock might *NOT* be held here. 205 */ 206 static void 207 sched_ithd_remote(void *arg) 208 { 209 sched_ithd((int)arg); 210 } 211 212 void 213 sched_ithd(int intr) 214 { 215 thread_t td; 216 217 if ((td = ithreads[intr]) != NULL) { 218 if (intlists[intr] == NULL) { 219 printf("sched_ithd: stray interrupt %d\n", intr); 220 } else { 221 if (td->td_gd == mycpu) { 222 irunning[intr] = 1; 223 lwkt_schedule(td); /* preemption handled internally */ 224 } else { 225 lwkt_send_ipiq(td->td_gd, sched_ithd_remote, (void *)intr); 226 } 227 } 228 } else { 229 printf("sched_ithd: stray interrupt %d\n", intr); 230 } 231 } 232 233 /* 234 * This is run from a periodic SYSTIMER (and thus must be MP safe, the BGL 235 * might not be held). 236 */ 237 static void 238 ithread_livelock_wakeup(systimer_t info) 239 { 240 int intr = (int)info->data; 241 thread_t td; 242 243 if ((td = ithreads[intr]) != NULL) 244 lwkt_schedule(td); 245 } 246 247 248 /* 249 * Interrupt threads run this as their main loop. The handler should be 250 * in a critical section on entry and the BGL is usually left held (for now). 251 * 252 * The irunning state starts at 0. When an interrupt occurs, the hardware 253 * interrupt is disabled and sched_ithd() The HW interrupt remains disabled 254 * until all routines have run. We then call ithread_done() to reenable 255 * the HW interrupt and deschedule us until the next interrupt. 256 */ 257 258 #define LIVELOCK_TIMEFRAME(freq) ((freq) >> 2) /* 1/4 second */ 259 260 static void 261 ithread_handler(void *arg) 262 { 263 int intr = (int)arg; 264 int freq; 265 u_int bticks; 266 u_int cputicks; 267 intrec_t **list = &intlists[intr]; 268 intrec_t *rec; 269 intrec_t *nrec; 270 struct random_softc *sc = &irandom_ary[intr]; 271 272 KKASSERT(curthread->td_pri >= TDPRI_CRIT); 273 for (;;) { 274 /* 275 * We can get woken up by the livelock periodic code too, run the 276 * handlers only if there is a real interrupt pending. Clear 277 * irunning[] prior to running the handlers to interlock new 278 * events. 279 */ 280 irunning[intr] = 0; 281 for (rec = *list; rec; rec = nrec) { 282 nrec = rec->next; 283 rec->handler(rec->argument); 284 } 285 286 /* 287 * This is our interrupt hook to add rate randomness to the random 288 * number generator. 289 */ 290 if (sc->sc_enabled) 291 add_interrupt_randomness(intr); 292 293 /* 294 * This is our livelock test. If we hit the rate limit we 295 * limit ourselves to 10000 interrupts/sec until the rate 296 * falls below 50% of that value, then we unlimit again. 297 */ 298 cputicks = cputimer_count(); 299 ++ill_count[intr]; 300 bticks = cputicks - ill_ticks[intr]; 301 ill_ticks[intr] = cputicks; 302 if (bticks > cputimer_freq) 303 bticks = cputimer_freq; 304 305 switch(ill_state[intr]) { 306 case LIVELOCK_NONE: 307 ill_delta[intr] += bticks; 308 if (ill_delta[intr] < LIVELOCK_TIMEFRAME(cputimer_freq)) 309 break; 310 freq = (int64_t)ill_count[intr] * cputimer_freq / ill_delta[intr]; 311 ill_delta[intr] = 0; 312 ill_count[intr] = 0; 313 if (freq < livelock_limit) 314 break; 315 printf("intr %d at %d hz, livelocked! limiting at %d hz\n", 316 intr, freq, livelock_fallback); 317 ill_state[intr] = LIVELOCK_LIMITED; 318 bticks = 0; 319 /* force periodic check to avoid stale removal (if ints stop) */ 320 systimer_init_periodic(&ill_rtimer[intr], ithread_livelock_wakeup, 321 (void *)intr, 1); 322 /* fall through */ 323 case LIVELOCK_LIMITED: 324 /* 325 * Delay (us) before rearming the interrupt 326 */ 327 systimer_init_oneshot(&ill_timer[intr], ithread_livelock_wakeup, 328 (void *)intr, 1 + 1000000 / livelock_fallback); 329 lwkt_deschedule_self(curthread); 330 lwkt_switch(); 331 332 /* in case we were woken up by something else */ 333 systimer_del(&ill_timer[intr]); 334 335 /* 336 * Calculate interrupt rate (note that due to our delay it 337 * will not exceed livelock_fallback). 338 */ 339 ill_delta[intr] += bticks; 340 if (ill_delta[intr] < LIVELOCK_TIMEFRAME(cputimer_freq)) 341 break; 342 freq = (int64_t)ill_count[intr] * cputimer_freq / ill_delta[intr]; 343 ill_delta[intr] = 0; 344 ill_count[intr] = 0; 345 if (freq < (livelock_fallback >> 1)) { 346 printf("intr %d at %d hz, removing livelock limit\n", 347 intr, freq); 348 ill_state[intr] = LIVELOCK_NONE; 349 systimer_del(&ill_rtimer[intr]); 350 } 351 break; 352 } 353 354 /* 355 * If another interrupt has not been queued we can reenable the 356 * hardware interrupt and go to sleep. 357 */ 358 if (irunning[intr] == 0) 359 ithread_done(intr); 360 } 361 } 362 363 /* 364 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt. 365 * The data for this machine dependent, and the declarations are in machine 366 * dependent code. The layout of intrnames and intrcnt however is machine 367 * independent. 368 * 369 * We do not know the length of intrcnt and intrnames at compile time, so 370 * calculate things at run time. 371 */ 372 static int 373 sysctl_intrnames(SYSCTL_HANDLER_ARGS) 374 { 375 return (sysctl_handle_opaque(oidp, intrnames, eintrnames - intrnames, 376 req)); 377 } 378 379 SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD, 380 NULL, 0, sysctl_intrnames, "", "Interrupt Names"); 381 382 static int 383 sysctl_intrcnt(SYSCTL_HANDLER_ARGS) 384 { 385 return (sysctl_handle_opaque(oidp, intrcnt, 386 (char *)eintrcnt - (char *)intrcnt, req)); 387 } 388 389 SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD, 390 NULL, 0, sysctl_intrcnt, "", "Interrupt Counts"); 391