1 /* 2 * Copyright 1998 Massachusetts Institute of Technology 3 * 4 * Permission to use, copy, modify, and distribute this software and 5 * its documentation for any purpose and without fee is hereby 6 * granted, provided that both the above copyright notice and this 7 * permission notice appear in all copies, that both the above 8 * copyright notice and this permission notice appear in all 9 * supporting documentation, and that the name of M.I.T. not be used 10 * in advertising or publicity pertaining to distribution of the 11 * software without specific, written prior permission. M.I.T. makes 12 * no representations about the suitability of this software for any 13 * purpose. It is provided "as is" without express or implied 14 * warranty. 15 * 16 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS 17 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE, 18 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT 20 * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 23 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 26 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $FreeBSD: src/sys/kern/subr_rman.c,v 1.10.2.1 2001/06/05 08:06:08 imp Exp $ 30 * $DragonFly: src/sys/kern/subr_rman.c,v 1.6 2004/03/01 06:33:17 dillon Exp $ 31 */ 32 33 /* 34 * The kernel resource manager. This code is responsible for keeping track 35 * of hardware resources which are apportioned out to various drivers. 36 * It does not actually assign those resources, and it is not expected 37 * that end-device drivers will call into this code directly. Rather, 38 * the code which implements the buses that those devices are attached to, 39 * and the code which manages CPU resources, will call this code, and the 40 * end-device drivers will make upcalls to that code to actually perform 41 * the allocation. 42 * 43 * There are two sorts of resources managed by this code. The first is 44 * the more familiar array (RMAN_ARRAY) type; resources in this class 45 * consist of a sequence of individually-allocatable objects which have 46 * been numbered in some well-defined order. Most of the resources 47 * are of this type, as it is the most familiar. The second type is 48 * called a gauge (RMAN_GAUGE), and models fungible resources (i.e., 49 * resources in which each instance is indistinguishable from every 50 * other instance). The principal anticipated application of gauges 51 * is in the context of power consumption, where a bus may have a specific 52 * power budget which all attached devices share. RMAN_GAUGE is not 53 * implemented yet. 54 * 55 * For array resources, we make one simplifying assumption: two clients 56 * sharing the same resource must use the same range of indices. That 57 * is to say, sharing of overlapping-but-not-identical regions is not 58 * permitted. 59 */ 60 61 #include <sys/param.h> 62 #include <sys/systm.h> 63 #include <sys/kernel.h> 64 #include <sys/lock.h> 65 #include <sys/malloc.h> 66 #include <sys/bus.h> /* XXX debugging */ 67 #include <machine/bus.h> 68 #include <sys/rman.h> 69 70 static MALLOC_DEFINE(M_RMAN, "rman", "Resource manager"); 71 72 struct rman_head rman_head; 73 static struct lwkt_token rman_tok; /* mutex to protect rman_head */ 74 static int int_rman_activate_resource(struct rman *rm, struct resource *r, 75 struct resource **whohas); 76 static int int_rman_deactivate_resource(struct resource *r); 77 static int int_rman_release_resource(struct rman *rm, struct resource *r); 78 79 #define CIRCLEQ_TERMCOND(var, head) (var == (void *)&(head)) 80 81 int 82 rman_init(struct rman *rm) 83 { 84 static int once; 85 lwkt_tokref ilock; 86 87 if (once == 0) { 88 once = 1; 89 TAILQ_INIT(&rman_head); 90 lwkt_token_init(&rman_tok); 91 } 92 93 if (rm->rm_type == RMAN_UNINIT) 94 panic("rman_init"); 95 if (rm->rm_type == RMAN_GAUGE) 96 panic("implement RMAN_GAUGE"); 97 98 CIRCLEQ_INIT(&rm->rm_list); 99 rm->rm_slock = malloc(sizeof *rm->rm_slock, M_RMAN, M_NOWAIT); 100 if (rm->rm_slock == NULL) 101 return ENOMEM; 102 lwkt_token_init(rm->rm_slock); 103 104 lwkt_gettoken(&ilock, &rman_tok); 105 TAILQ_INSERT_TAIL(&rman_head, rm, rm_link); 106 lwkt_reltoken(&ilock); 107 return 0; 108 } 109 110 /* 111 * NB: this interface is not robust against programming errors which 112 * add multiple copies of the same region. 113 */ 114 int 115 rman_manage_region(struct rman *rm, u_long start, u_long end) 116 { 117 struct resource *r, *s; 118 lwkt_tokref ilock; 119 120 r = malloc(sizeof *r, M_RMAN, M_NOWAIT); 121 if (r == 0) 122 return ENOMEM; 123 bzero(r, sizeof *r); 124 r->r_sharehead = 0; 125 r->r_start = start; 126 r->r_end = end; 127 r->r_flags = 0; 128 r->r_dev = 0; 129 r->r_rm = rm; 130 131 lwkt_gettoken(&ilock, rm->rm_slock); 132 for (s = CIRCLEQ_FIRST(&rm->rm_list); 133 !CIRCLEQ_TERMCOND(s, rm->rm_list) && s->r_end < r->r_start; 134 s = CIRCLEQ_NEXT(s, r_link)) 135 ; 136 137 if (CIRCLEQ_TERMCOND(s, rm->rm_list)) { 138 CIRCLEQ_INSERT_TAIL(&rm->rm_list, r, r_link); 139 } else { 140 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, s, r, r_link); 141 } 142 143 lwkt_reltoken(&ilock); 144 return 0; 145 } 146 147 int 148 rman_fini(struct rman *rm) 149 { 150 struct resource *r; 151 lwkt_tokref ilock; 152 153 lwkt_gettoken(&ilock, rm->rm_slock); 154 CIRCLEQ_FOREACH(r, &rm->rm_list, r_link) { 155 if (r->r_flags & RF_ALLOCATED) { 156 lwkt_reltoken(&ilock); 157 return EBUSY; 158 } 159 } 160 161 /* 162 * There really should only be one of these if we are in this 163 * state and the code is working properly, but it can't hurt. 164 */ 165 while (!CIRCLEQ_EMPTY(&rm->rm_list)) { 166 r = CIRCLEQ_FIRST(&rm->rm_list); 167 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 168 free(r, M_RMAN); 169 } 170 lwkt_reltoken(&ilock); 171 /* XXX what's the point of this if we are going to free the struct? */ 172 lwkt_gettoken(&ilock, &rman_tok); 173 TAILQ_REMOVE(&rman_head, rm, rm_link); 174 lwkt_reltoken(&ilock); 175 free(rm->rm_slock, M_RMAN); 176 177 return 0; 178 } 179 180 struct resource * 181 rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count, 182 u_int flags, struct device *dev) 183 { 184 u_int want_activate; 185 struct resource *r, *s, *rv; 186 u_long rstart, rend; 187 lwkt_tokref ilock; 188 189 rv = 0; 190 191 #ifdef RMAN_DEBUG 192 printf("rman_reserve_resource: <%s> request: [%#lx, %#lx], length " 193 "%#lx, flags %u, device %s%d\n", rm->rm_descr, start, end, 194 count, flags, device_get_name(dev), device_get_unit(dev)); 195 #endif /* RMAN_DEBUG */ 196 want_activate = (flags & RF_ACTIVE); 197 flags &= ~RF_ACTIVE; 198 199 lwkt_gettoken(&ilock, rm->rm_slock); 200 201 for (r = CIRCLEQ_FIRST(&rm->rm_list); 202 !CIRCLEQ_TERMCOND(r, rm->rm_list) && r->r_end < start; 203 r = CIRCLEQ_NEXT(r, r_link)) 204 ; 205 206 if (CIRCLEQ_TERMCOND(r, rm->rm_list)) { 207 #ifdef RMAN_DEBUG 208 printf("could not find a region\n"); 209 #endif 210 goto out; 211 } 212 213 /* 214 * First try to find an acceptable totally-unshared region. 215 */ 216 for (s = r; !CIRCLEQ_TERMCOND(s, rm->rm_list); 217 s = CIRCLEQ_NEXT(s, r_link)) { 218 #ifdef RMAN_DEBUG 219 printf("considering [%#lx, %#lx]\n", s->r_start, s->r_end); 220 #endif /* RMAN_DEBUG */ 221 if (s->r_start > end) { 222 #ifdef RMAN_DEBUG 223 printf("s->r_start (%#lx) > end (%#lx)\n", s->r_start, end); 224 #endif /* RMAN_DEBUG */ 225 break; 226 } 227 if (s->r_flags & RF_ALLOCATED) { 228 #ifdef RMAN_DEBUG 229 printf("region is allocated\n"); 230 #endif /* RMAN_DEBUG */ 231 continue; 232 } 233 rstart = max(s->r_start, start); 234 rstart = (rstart + ((1ul << RF_ALIGNMENT(flags))) - 1) & 235 ~((1ul << RF_ALIGNMENT(flags)) - 1); 236 rend = min(s->r_end, max(start + count, end)); 237 #ifdef RMAN_DEBUG 238 printf("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n", 239 rstart, rend, (rend - rstart + 1), count); 240 #endif /* RMAN_DEBUG */ 241 242 if ((rend - rstart + 1) >= count) { 243 #ifdef RMAN_DEBUG 244 printf("candidate region: [%#lx, %#lx], size %#lx\n", 245 rend, rstart, (rend - rstart + 1)); 246 #endif /* RMAN_DEBUG */ 247 if ((s->r_end - s->r_start + 1) == count) { 248 #ifdef RMAN_DEBUG 249 printf("candidate region is entire chunk\n"); 250 #endif /* RMAN_DEBUG */ 251 rv = s; 252 rv->r_flags |= RF_ALLOCATED | flags; 253 rv->r_dev = dev; 254 goto out; 255 } 256 257 /* 258 * If s->r_start < rstart and 259 * s->r_end > rstart + count - 1, then 260 * we need to split the region into three pieces 261 * (the middle one will get returned to the user). 262 * Otherwise, we are allocating at either the 263 * beginning or the end of s, so we only need to 264 * split it in two. The first case requires 265 * two new allocations; the second requires but one. 266 */ 267 rv = malloc(sizeof *rv, M_RMAN, M_NOWAIT); 268 if (rv == 0) 269 goto out; 270 bzero(rv, sizeof *rv); 271 rv->r_start = rstart; 272 rv->r_end = rstart + count - 1; 273 rv->r_flags = flags | RF_ALLOCATED; 274 rv->r_dev = dev; 275 rv->r_sharehead = 0; 276 rv->r_rm = rm; 277 278 if (s->r_start < rv->r_start && s->r_end > rv->r_end) { 279 #ifdef RMAN_DEBUG 280 printf("splitting region in three parts: " 281 "[%#lx, %#lx]; [%#lx, %#lx]; [%#lx, %#lx]\n", 282 s->r_start, rv->r_start - 1, 283 rv->r_start, rv->r_end, 284 rv->r_end + 1, s->r_end); 285 #endif /* RMAN_DEBUG */ 286 /* 287 * We are allocating in the middle. 288 */ 289 r = malloc(sizeof *r, M_RMAN, M_NOWAIT); 290 if (r == 0) { 291 free(rv, M_RMAN); 292 rv = 0; 293 goto out; 294 } 295 bzero(r, sizeof *r); 296 r->r_start = rv->r_end + 1; 297 r->r_end = s->r_end; 298 r->r_flags = s->r_flags; 299 r->r_dev = 0; 300 r->r_sharehead = 0; 301 r->r_rm = rm; 302 s->r_end = rv->r_start - 1; 303 CIRCLEQ_INSERT_AFTER(&rm->rm_list, s, rv, 304 r_link); 305 CIRCLEQ_INSERT_AFTER(&rm->rm_list, rv, r, 306 r_link); 307 } else if (s->r_start == rv->r_start) { 308 #ifdef RMAN_DEBUG 309 printf("allocating from the beginning\n"); 310 #endif /* RMAN_DEBUG */ 311 /* 312 * We are allocating at the beginning. 313 */ 314 s->r_start = rv->r_end + 1; 315 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, s, rv, 316 r_link); 317 } else { 318 #ifdef RMAN_DEBUG 319 printf("allocating at the end\n"); 320 #endif /* RMAN_DEBUG */ 321 /* 322 * We are allocating at the end. 323 */ 324 s->r_end = rv->r_start - 1; 325 CIRCLEQ_INSERT_AFTER(&rm->rm_list, s, rv, 326 r_link); 327 } 328 goto out; 329 } 330 } 331 332 /* 333 * Now find an acceptable shared region, if the client's requirements 334 * allow sharing. By our implementation restriction, a candidate 335 * region must match exactly by both size and sharing type in order 336 * to be considered compatible with the client's request. (The 337 * former restriction could probably be lifted without too much 338 * additional work, but this does not seem warranted.) 339 */ 340 #ifdef RMAN_DEBUG 341 printf("no unshared regions found\n"); 342 #endif /* RMAN_DEBUG */ 343 if ((flags & (RF_SHAREABLE | RF_TIMESHARE)) == 0) 344 goto out; 345 346 for (s = r; !CIRCLEQ_TERMCOND(s, rm->rm_list); 347 s = CIRCLEQ_NEXT(s, r_link)) { 348 if (s->r_start > end) 349 break; 350 if ((s->r_flags & flags) != flags) 351 continue; 352 rstart = max(s->r_start, start); 353 rend = min(s->r_end, max(start + count, end)); 354 if (s->r_start >= start && s->r_end <= end 355 && (s->r_end - s->r_start + 1) == count) { 356 rv = malloc(sizeof *rv, M_RMAN, M_NOWAIT); 357 if (rv == 0) 358 goto out; 359 bzero(rv, sizeof *rv); 360 rv->r_start = s->r_start; 361 rv->r_end = s->r_end; 362 rv->r_flags = s->r_flags & 363 (RF_ALLOCATED | RF_SHAREABLE | RF_TIMESHARE); 364 rv->r_dev = dev; 365 rv->r_rm = rm; 366 if (s->r_sharehead == 0) { 367 s->r_sharehead = malloc(sizeof *s->r_sharehead, 368 M_RMAN, M_NOWAIT); 369 if (s->r_sharehead == 0) { 370 free(rv, M_RMAN); 371 rv = 0; 372 goto out; 373 } 374 bzero(s->r_sharehead, sizeof *s->r_sharehead); 375 LIST_INIT(s->r_sharehead); 376 LIST_INSERT_HEAD(s->r_sharehead, s, 377 r_sharelink); 378 s->r_flags |= RF_FIRSTSHARE; 379 } 380 rv->r_sharehead = s->r_sharehead; 381 LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink); 382 goto out; 383 } 384 } 385 386 /* 387 * We couldn't find anything. 388 */ 389 out: 390 /* 391 * If the user specified RF_ACTIVE in the initial flags, 392 * which is reflected in `want_activate', we attempt to atomically 393 * activate the resource. If this fails, we release the resource 394 * and indicate overall failure. (This behavior probably doesn't 395 * make sense for RF_TIMESHARE-type resources.) 396 */ 397 if (rv && want_activate) { 398 struct resource *whohas; 399 if (int_rman_activate_resource(rm, rv, &whohas)) { 400 int_rman_release_resource(rm, rv); 401 rv = 0; 402 } 403 } 404 lwkt_reltoken(&ilock); 405 return (rv); 406 } 407 408 static int 409 int_rman_activate_resource(struct rman *rm, struct resource *r, 410 struct resource **whohas) 411 { 412 struct resource *s; 413 int ok; 414 415 /* 416 * If we are not timesharing, then there is nothing much to do. 417 * If we already have the resource, then there is nothing at all to do. 418 * If we are not on a sharing list with anybody else, then there is 419 * little to do. 420 */ 421 if ((r->r_flags & RF_TIMESHARE) == 0 422 || (r->r_flags & RF_ACTIVE) != 0 423 || r->r_sharehead == 0) { 424 r->r_flags |= RF_ACTIVE; 425 return 0; 426 } 427 428 ok = 1; 429 for (s = LIST_FIRST(r->r_sharehead); s && ok; 430 s = LIST_NEXT(s, r_sharelink)) { 431 if ((s->r_flags & RF_ACTIVE) != 0) { 432 ok = 0; 433 *whohas = s; 434 } 435 } 436 if (ok) { 437 r->r_flags |= RF_ACTIVE; 438 return 0; 439 } 440 return EBUSY; 441 } 442 443 int 444 rman_activate_resource(struct resource *r) 445 { 446 int rv; 447 struct resource *whohas; 448 lwkt_tokref ilock; 449 struct rman *rm; 450 451 rm = r->r_rm; 452 lwkt_gettoken(&ilock, rm->rm_slock); 453 rv = int_rman_activate_resource(rm, r, &whohas); 454 lwkt_reltoken(&ilock); 455 return rv; 456 } 457 458 #if 0 459 460 /* XXX */ 461 int 462 rman_await_resource(struct resource *r, lwkt_tokref_t ilock, int slpflags, int timo) 463 { 464 int rv, s; 465 struct resource *whohas; 466 struct rman *rm; 467 468 rm = r->r_rm; 469 for (;;) { 470 lwkt_gettoken(ilock, rm->rm_slock); 471 rv = int_rman_activate_resource(rm, r, &whohas); 472 if (rv != EBUSY) 473 return (rv); /* returns with ilock held */ 474 475 if (r->r_sharehead == 0) 476 panic("rman_await_resource"); 477 /* 478 * splhigh hopefully will prevent a race between 479 * lwkt_reltoken and tsleep where a process 480 * could conceivably get in and release the resource 481 * before we have a chance to sleep on it. YYY 482 */ 483 s = splhigh(); 484 whohas->r_flags |= RF_WANTED; 485 rv = tsleep(r->r_sharehead, slpflags, "rmwait", timo); 486 if (rv) { 487 lwkt_reltoken(ilock); 488 splx(s); 489 return rv; 490 } 491 splx(s); 492 } 493 } 494 495 #endif 496 497 static int 498 int_rman_deactivate_resource(struct resource *r) 499 { 500 struct rman *rm; 501 502 rm = r->r_rm; 503 r->r_flags &= ~RF_ACTIVE; 504 if (r->r_flags & RF_WANTED) { 505 r->r_flags &= ~RF_WANTED; 506 wakeup(r->r_sharehead); 507 } 508 return 0; 509 } 510 511 int 512 rman_deactivate_resource(struct resource *r) 513 { 514 lwkt_tokref ilock; 515 struct rman *rm; 516 517 rm = r->r_rm; 518 lwkt_gettoken(&ilock, rm->rm_slock); 519 int_rman_deactivate_resource(r); 520 lwkt_reltoken(&ilock); 521 return 0; 522 } 523 524 static int 525 int_rman_release_resource(struct rman *rm, struct resource *r) 526 { 527 struct resource *s, *t; 528 529 if (r->r_flags & RF_ACTIVE) 530 int_rman_deactivate_resource(r); 531 532 /* 533 * Check for a sharing list first. If there is one, then we don't 534 * have to think as hard. 535 */ 536 if (r->r_sharehead) { 537 /* 538 * If a sharing list exists, then we know there are at 539 * least two sharers. 540 * 541 * If we are in the main circleq, appoint someone else. 542 */ 543 LIST_REMOVE(r, r_sharelink); 544 s = LIST_FIRST(r->r_sharehead); 545 if (r->r_flags & RF_FIRSTSHARE) { 546 s->r_flags |= RF_FIRSTSHARE; 547 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, r, s, r_link); 548 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 549 } 550 551 /* 552 * Make sure that the sharing list goes away completely 553 * if the resource is no longer being shared at all. 554 */ 555 if (LIST_NEXT(s, r_sharelink) == 0) { 556 free(s->r_sharehead, M_RMAN); 557 s->r_sharehead = 0; 558 s->r_flags &= ~RF_FIRSTSHARE; 559 } 560 goto out; 561 } 562 563 /* 564 * Look at the adjacent resources in the list and see if our 565 * segment can be merged with any of them. 566 */ 567 s = CIRCLEQ_PREV(r, r_link); 568 t = CIRCLEQ_NEXT(r, r_link); 569 570 if (s != (void *)&rm->rm_list && (s->r_flags & RF_ALLOCATED) == 0 571 && t != (void *)&rm->rm_list && (t->r_flags & RF_ALLOCATED) == 0) { 572 /* 573 * Merge all three segments. 574 */ 575 s->r_end = t->r_end; 576 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 577 CIRCLEQ_REMOVE(&rm->rm_list, t, r_link); 578 free(t, M_RMAN); 579 } else if (s != (void *)&rm->rm_list 580 && (s->r_flags & RF_ALLOCATED) == 0) { 581 /* 582 * Merge previous segment with ours. 583 */ 584 s->r_end = r->r_end; 585 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 586 } else if (t != (void *)&rm->rm_list 587 && (t->r_flags & RF_ALLOCATED) == 0) { 588 /* 589 * Merge next segment with ours. 590 */ 591 t->r_start = r->r_start; 592 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 593 } else { 594 /* 595 * At this point, we know there is nothing we 596 * can potentially merge with, because on each 597 * side, there is either nothing there or what is 598 * there is still allocated. In that case, we don't 599 * want to remove r from the list; we simply want to 600 * change it to an unallocated region and return 601 * without freeing anything. 602 */ 603 r->r_flags &= ~RF_ALLOCATED; 604 return 0; 605 } 606 607 out: 608 free(r, M_RMAN); 609 return 0; 610 } 611 612 int 613 rman_release_resource(struct resource *r) 614 { 615 struct rman *rm = r->r_rm; 616 lwkt_tokref ilock; 617 int rv; 618 619 lwkt_gettoken(&ilock, rm->rm_slock); 620 rv = int_rman_release_resource(rm, r); 621 lwkt_reltoken(&ilock); 622 return (rv); 623 } 624 625 uint32_t 626 rman_make_alignment_flags(uint32_t size) 627 { 628 int i; 629 630 /* 631 * Find the hightest bit set, and add one if more than one bit 632 * set. We're effectively computing the ceil(log2(size)) here. 633 */ 634 for (i = 32; i > 0; i--) 635 if ((1 << i) & size) 636 break; 637 if (~(1 << i) & size) 638 i++; 639 640 return(RF_ALIGNMENT_LOG2(i)); 641 } 642