1 /* 2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * $DragonFly: src/sys/kern/kern_systimer.c,v 1.12 2007/10/16 11:12:59 sephe Exp $ 35 */ 36 37 /* 38 * WARNING! THE SYSTIMER MODULE DOES NOT OPERATE OR DISPATCH WITH THE 39 * MP LOCK HELD. ALL CODE USING THIS MODULE MUST BE MP-SAFE. 40 * 41 * This code implements a fine-grained per-cpu system timer which is 42 * ultimately based on a hardware timer. The hardware timer abstraction 43 * is sufficiently disconnected from this code to support both per-cpu 44 * hardware timers or a single system-wide hardware timer. 45 * 46 * WARNING! During early boot if a new system timer is selected, existing 47 * timeouts will not be effected and will thus occur slower or faster. 48 * periodic timers will be adjusted at the next periodic load. 49 * 50 * Notes on machine-dependant code (in arch/arch/systimer.c) 51 * 52 * cputimer_intr_reload() Reload the one-shot (per-cpu basis) 53 */ 54 55 #include <sys/param.h> 56 #include <sys/kernel.h> 57 #include <sys/systm.h> 58 #include <sys/thread.h> 59 #include <sys/globaldata.h> 60 #include <sys/systimer.h> 61 #include <sys/thread2.h> 62 63 /* 64 * Execute ready systimers. Called directly from the platform-specific 65 * one-shot timer clock interrupt (e.g. clkintr()) or via an IPI. May 66 * be called simultaniously on multiple cpus and always operations on 67 * the current cpu's queue. Systimer functions are responsible for calling 68 * hardclock, statclock, and other finely-timed routines. 69 */ 70 void 71 systimer_intr(sysclock_t *timep, int dummy, struct intrframe *frame) 72 { 73 globaldata_t gd = mycpu; 74 sysclock_t time = *timep; 75 systimer_t info; 76 77 if (gd->gd_syst_nest) 78 return; 79 80 crit_enter(); 81 ++gd->gd_syst_nest; 82 while ((info = TAILQ_FIRST(&gd->gd_systimerq)) != NULL) { 83 /* 84 * If we haven't reached the requested time, tell the cputimer 85 * how much is left and break out. 86 */ 87 if ((int)(info->time - time) > 0) { 88 cputimer_intr_reload(info->time - time); 89 break; 90 } 91 92 /* 93 * Dequeue and execute, detect a loss of the systimer. Note 94 * that the in-progress systimer pointer can only be used to 95 * detect a loss of the systimer, it is only useful within 96 * this code sequence and becomes stale otherwise. 97 */ 98 info->flags &= ~SYSTF_ONQUEUE; 99 TAILQ_REMOVE(info->queue, info, node); 100 gd->gd_systimer_inprog = info; 101 crit_exit(); 102 info->func(info, frame); 103 crit_enter(); 104 105 /* 106 * The caller may deleted or even re-queue the systimer itself 107 * with a delete/add sequence. If the caller does not mess with 108 * the systimer we will requeue the periodic interval automatically. 109 * 110 * If this is a non-queued periodic interrupt, do not allow multiple 111 * events to build up (used for things like the callout timer to 112 * prevent premature timeouts due to long interrupt disablements, 113 * BIOS 8254 glitching, and so forth). However, we still want to 114 * keep things synchronized between cpus for efficient handling of 115 * the timer interrupt so jump in multiples of the periodic rate. 116 */ 117 if (gd->gd_systimer_inprog == info && info->periodic) { 118 if (info->which != sys_cputimer) { 119 info->periodic = sys_cputimer->fromhz(info->freq); 120 info->which = sys_cputimer; 121 } 122 info->time += info->periodic; 123 if ((info->flags & SYSTF_NONQUEUED) && 124 (int)(info->time - time) <= 0 125 ) { 126 info->time += ((time - info->time + info->periodic - 1) / 127 info->periodic) * info->periodic; 128 } 129 systimer_add(info); 130 } 131 gd->gd_systimer_inprog = NULL; 132 } 133 --gd->gd_syst_nest; 134 crit_exit(); 135 } 136 137 void 138 systimer_intr_enable(void) 139 { 140 cputimer_intr_enable(); 141 } 142 143 void 144 systimer_add(systimer_t info) 145 { 146 struct globaldata *gd = mycpu; 147 148 KKASSERT((info->flags & SYSTF_ONQUEUE) == 0); 149 crit_enter(); 150 if (info->gd == gd) { 151 systimer_t scan1; 152 systimer_t scan2; 153 scan1 = TAILQ_FIRST(&gd->gd_systimerq); 154 if (scan1 == NULL || (int)(scan1->time - info->time) > 0) { 155 cputimer_intr_reload(info->time - sys_cputimer->count()); 156 TAILQ_INSERT_HEAD(&gd->gd_systimerq, info, node); 157 } else { 158 scan2 = TAILQ_LAST(&gd->gd_systimerq, systimerq); 159 for (;;) { 160 if (scan1 == NULL) { 161 TAILQ_INSERT_TAIL(&gd->gd_systimerq, info, node); 162 break; 163 } 164 if ((int)(scan1->time - info->time) > 0) { 165 TAILQ_INSERT_BEFORE(scan1, info, node); 166 break; 167 } 168 if ((int)(scan2->time - info->time) <= 0) { 169 TAILQ_INSERT_AFTER(&gd->gd_systimerq, scan2, info, node); 170 break; 171 } 172 scan1 = TAILQ_NEXT(scan1, node); 173 scan2 = TAILQ_PREV(scan2, systimerq, node); 174 } 175 } 176 info->flags = (info->flags | SYSTF_ONQUEUE) & ~SYSTF_IPIRUNNING; 177 info->queue = &gd->gd_systimerq; 178 } else { 179 #ifdef SMP 180 KKASSERT((info->flags & SYSTF_IPIRUNNING) == 0); 181 info->flags |= SYSTF_IPIRUNNING; 182 lwkt_send_ipiq(info->gd, (ipifunc1_t)systimer_add, info); 183 #else 184 panic("systimer_add: bad gd in info %p", info); 185 #endif 186 } 187 crit_exit(); 188 } 189 190 /* 191 * systimer_del() 192 * 193 * Delete a system timer. Only the owning cpu can delete a timer. 194 */ 195 void 196 systimer_del(systimer_t info) 197 { 198 struct globaldata *gd = info->gd; 199 200 KKASSERT(gd == mycpu && (info->flags & SYSTF_IPIRUNNING) == 0); 201 202 crit_enter(); 203 204 if (info->flags & SYSTF_ONQUEUE) { 205 TAILQ_REMOVE(info->queue, info, node); 206 info->flags &= ~SYSTF_ONQUEUE; 207 } 208 209 /* 210 * Deal with dispatch races by clearing the in-progress systimer 211 * pointer. Only a direct pointer comparison can be used, the 212 * actual contents of the structure gd_systimer_inprog points to, 213 * if not equal to info, may be stale. 214 */ 215 if (gd->gd_systimer_inprog == info) 216 gd->gd_systimer_inprog = NULL; 217 218 crit_exit(); 219 } 220 221 /* 222 * systimer_init_periodic() 223 * 224 * Initialize a periodic timer at the specified frequency and add 225 * it to the system. The frequency is uncompensated and approximate. 226 * 227 * Try to synchronize multi registrations of the same or similar 228 * frequencies so the hardware interrupt is able to dispatch several 229 * at together by adjusting the phase of the initial interrupt. This 230 * helps SMP. Note that we are not attempting to synchronize to 231 * the realtime clock. 232 */ 233 void 234 systimer_init_periodic(systimer_t info, void *func, void *data, int hz) 235 { 236 sysclock_t base_count; 237 238 bzero(info, sizeof(struct systimer)); 239 info->periodic = sys_cputimer->fromhz(hz); 240 base_count = sys_cputimer->count(); 241 base_count = base_count - (base_count % info->periodic); 242 info->time = base_count + info->periodic; 243 info->func = func; 244 info->data = data; 245 info->freq = hz; 246 info->which = sys_cputimer; 247 info->gd = mycpu; 248 systimer_add(info); 249 } 250 251 void 252 systimer_init_periodic_nq(systimer_t info, void *func, void *data, int hz) 253 { 254 sysclock_t base_count; 255 256 bzero(info, sizeof(struct systimer)); 257 info->periodic = sys_cputimer->fromhz(hz); 258 base_count = sys_cputimer->count(); 259 base_count = base_count - (base_count % info->periodic); 260 info->time = base_count + info->periodic; 261 info->func = func; 262 info->data = data; 263 info->freq = hz; 264 info->which = sys_cputimer; 265 info->gd = mycpu; 266 info->flags |= SYSTF_NONQUEUED; 267 systimer_add(info); 268 } 269 270 /* 271 * Adjust the periodic interval for a periodic timer which is already 272 * running. The current timeout is not effected. 273 */ 274 void 275 systimer_adjust_periodic(systimer_t info, int hz) 276 { 277 crit_enter(); 278 info->periodic = sys_cputimer->fromhz(hz); 279 info->freq = hz; 280 info->which = sys_cputimer; 281 crit_exit(); 282 } 283 284 /* 285 * systimer_init_oneshot() 286 * 287 * Initialize a periodic timer at the specified frequency and add 288 * it to the system. The frequency is uncompensated and approximate. 289 */ 290 void 291 systimer_init_oneshot(systimer_t info, void *func, void *data, int us) 292 { 293 bzero(info, sizeof(struct systimer)); 294 info->time = sys_cputimer->count() + sys_cputimer->fromus(us); 295 info->func = func; 296 info->data = data; 297 info->which = sys_cputimer; 298 info->gd = mycpu; 299 systimer_add(info); 300 } 301 302